SimpleBGC 32bit 3-Axis Software User Manual

SimpleBGC 32bit 3-Axis Software User Manual
SimpleBGC 32bit 3-Axis
Software User Manual
Board v. 3.x
Firmware v. 2.5x
GUI v. 2.5x
© Basecamelectronics® 2013-2015
CONTENTS
1. Overview................................................................................. 3
2. Step-by-step setup sequence................................................9
3. The Basecam GUI overview.................................................13
4. Basic Settings.......................................................................15
5. PID auto-tuning....................................................................23
6. RC Settings............................................................................25
7. Follow Mode Settings..........................................................30
8. Advanced Settings................................................................33
9. Service Settings....................................................................35
10. System Monitoring............................................................38
11. Digital Filters.....................................................................39
12. Adjustable Variables..........................................................42
13. Firmware update................................................................46
14. System Analysis Tool.........................................................50
15. User-written scripts...........................................................54
16. Encoders.............................................................................55
17. Magnetometer sensor........................................................57
18. Bluetooth module configuration......................................60
19. Possible problems and solutions......................................62
20. Credits.................................................................................63
© Basecam Electronics® 2013-2015
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1. Overview
1. Overview
This manual provides directions on how to connect, adjust and calibrate the SimpleBGC 32bit 3-Axis
controller board by Basecam Electronics. To begin using the board the following are the components that
are necessary to assemble. The controller board and additionally either one or two IMU units. A USB
connection to the board or an optional Bluetooth converter (a standard TTL interface Bluetooth module
readily available in the market). A computer to make and write settings to the controller via Basecam's
software. And the Basecam software which runs on Windows, MacOS and Linux. The software is
downloaded from the Basecam website. Note that the GUI software version should match (or be greater
than) the firmware version deployed on the board.
Also necessary is a suitable physical apparatus to mount and orient the sensors for use during calibrationnot a gimbal itself but rather a small cube of any material, cardboard foam, wood etc. that has true square
sides which can be turned from side to side during calibration (further described later). Also needed
ultimately is a gimbal with 2 or 3 brushless motors, that is well balanced in each dimension about its
center point. The objective for gimbal design is that the center of effort be a fixed unmoving pointirrespective of the position of the gimbals arms and that the camera (the stabilized device) be centered- its
mass centered- at that point. Additional optional components such as switches, joystick operation and
interfaces to remote control devices (PWM or S.Bus from a standard RC receiver) are described in detail
farther on.
SimpleBGC actively compensates for undesirable movement in the stabilized portion of the gimbal (which
mounts a camera or other device) that requires precise positioning irrespective of movement in the
surrounding frame of reference. The controllers high performance motion sensors (MEMS gyros) and ARM
Cortex(TM) 32 bit core and additional capabilities to integrate PWM control (and other) signals directly to the
stabilized devise makes the controller an ideal platform for applications from stabilized hand carried
camera mounts to more complex objectives such as track and boom carried or aerial mounted applications.
Stabilizing is accomplished by directing energy to the gimbal motors in response to reception of
repositioning data from the gyroscopic sensor(s). The primary gyroscopic sensor is mounted on the camera
to register precisely any repositioning (to be compensated). Either one or two sensors can be used - a
Primary IMU (sensor) which is attached to the camera and optionally a Frame IMU (sensor) which is
attached to the frame in one of two positions). When two sensors are attached data from both is used by
the controller board simultaneously for more precise system stabilization. To improve system performance,
optional rotary position sensor (encoder) may be installed on each motor. More info about advantages and
requirements of using encoders, you can find on the page http://www.basecamelectronics.com/encoders/
The controller itself is compact (17 grams) but directs 1.6 Amps at 20V to each axis, which gives it the
power to drive large gimbal motors (80mm to 110mm is quite reasonable) when amperage and voltage
levels are observed. This translates to a maximum payload of about 25lbs (the weight of a Red(TM) Cinema
camera and prime lens) if properly mounted and balanced and depending upon the rate of correction
expected and other operational factors. Correction rates (that result) are increased by novel and demanding
applications such as mounting to moving or flying vehicles. Many factors must be taken into consideration
when determining fitness for a proposed use, but in particular the payload weight, balance, gimbal quality,
g-forces that will likely be encountered and the magnitude of wind speed and turbulence all contribute.
© Basecamelectronics® 2013-2015
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1. Overview
Introduction
The system controller board and software are designed and licensed by Basecam Electronics. You can
purchase our controller directly from us at our web store (http://www.basecamelectronics.ru/store/) or you may
purchase one manufactured under contract by one of our partners. The list of our official partners is
available on our web site http://www.basecamelectronics.ru/wheretobuy/. Different manufacturers may alter the
controller slightly (for example, by adding an integrated Bluetooth component or by changing its size etc.).
In either case note the board version and relevant data published on the corresponding manufacturer's web
site.
Some of our partners make just the boards available and others make finished gimbal products with preinstalled controllers (http://www.basecamelectronics.com/readytouse/). Gimbals are also available (both with and
without motors) but without electronic stabilization system. In these case you will need to purchase a
controller (from us as noted above or from one of our partners providing just the boards) and install it
yourself. If you decide to assemble a stabilization system yourself, please visit our forum where you can
find the necessary information (http://forum.basecamelectronics.com).
We describe in this manual both the controller board itself as well as the multi-platform (software)
application for its adjustment. We call the software application (the) Basecam GUI. As noted it may be
downloaded from our website and also as noted above it is necessary to get the version of it that is
associated with the firmware version that is installed on the board (the versions should match).
The Basecam GUI software uses the Java runtime environment and a virtual COM port to aid in portability
to other systems. Depending on the platform you may need to issue some commands to enable the port,
and (on some platforms) it may be necessary to install a serial driver. Once running and connected the GUI
looks and runs the same on all platforms. Note that when Bluetooth is employed as the serial bridge
(rather than plugging the board into a computer with a USB cable) that it may be necessary to configure the
bluetooth device separately from running our software. See below for more details.
© Basecamelectronics® 2013-2015
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1. Overview
Basic connections
The connection scheme for the basic controller board is shown in figure 1:
Battery 8-25V
YAW motor
USB to PC
ROLL motor
I2C to IMU
PITCH motor
Menu
button
RC
receiver
Fig.1 Basic connections
1. The USB port is used to connect the SimpleBGC 32bit stabilization board to PC.
2. Gyroscopic sensor(s) (IMU's) are connected to I2C slot. When there is a second IMU their outputs are
combined with an Y-cable and in either case a single connection is made to the port as shown.
3. Each axis motor is connected to the corresponding motor connection. These outputs are connected
directly to the brushless gimbal motors. If any output is not used, disable it in the GUI.
NOTE: It is advisable to pull each motor cable through (and make at least one loop around) a ferrite ring to avoid
high frequency interference from affecting the IMU sensors and other electronic devices (both on and connected to
the board).
4. The controller board is equipped with a power cable for connection to a battery. To avoid
connection interruptions it is recommended that you solder the wires to these pins from the
corresponding connector to your battery and include some form of physical strain relief. Note
Polarity at all times, do not make an incorrect connection. Even a brief (instantaneous) incorrect
connection may damage (or destroy) the board (and perhaps the battery).
When handling batteries, never cross terminals, even momentarily. Particularly when handling lithium batteries,
accidentally locking terminals may very definitely cause a fire or explosion! Use great care particularly when cutting and
soldering battery leads to prevent any contact of opposite poles in a closed circuit.
© Basecamelectronics® 2013-2015
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1. Overview
NOTE: Battery voltage of 8 to 25V is acceptable. If you use a lithium-polymer battery (LiPo), 3S to 5S inclusive are
acceptable, where S stands for the quantity of (standard 3.6v nominal) cells in a given battery. Note the voltage
maximum for (most) such cells is 4.2V when fully charged. Consequently, a fully charged 3S LiPo is equal to 12.6V and
5S LiPo is equal to 21V. Heed all warning indications regarding safe handling of lithium polymer batteries. Remember
that LiPoly batteries use only chargers specifically designed for this chemistry. Never connect a LiPoly battery to a
charger not intended for this battery chemistry.
A detailed description of a controller connection within a complete stabilization system can be found in the
detailed connection scheme.
GUI installation
First you need to download the latest version of the GUI application from our web site
(http://www.basecamelectronics.com/downloads/32bit/). Unpack it in any folder. To start the application you need
to have the Java Runtime Environment (managed by Oracle Inc) installed in your system. To obtain the
product for your system see http://www.java.com. For each of the systems, in the unpack directory:
To run the Basecam GUI for Windows:
•
run SimpleBGC_GUI.exe
To run the Basecam GUI for MAC OS:
• run SimpleBGC_GUI.jar
ATTENTION: The Basecam GUI uses a virtual COM port. To get that to work (on MacOS) a lock file will need to be
created (it uses the lock file to control flow back and forth through the virtual COM port). Due to security constraints,
you need to create the lock file yourself. Start terminal (Terminal is an application in the Utilities directory).
Into terminal- type- with great care if you are less experienced:
Make folder "/var/lock" by command:
1. sudo mkdir /var/lock
Change permissions by command:
2. sudo chmod 777 /var/lock
Either allow your system to run non-signed applications by setting this in:
System Preferences > Security & Privacy > General > Allow Applications downloaded from: Anywhere
Or you can allow just this one app to run by answering Open when prompted by the system dialog. In this
case, as in the other navigate to the unpack directory and
3. double click (to run) SimpleBGC_GUI.jar
To run the Basecam GUI for LINUX:
• run run.sh
© Basecamelectronics® 2013-2015
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1. Overview
Connection to computer
The controller has either a Mini- or Micro-USB (depending on the version). To connect the board to the
computer you will need to install a driver to first establish a connection. If the driver is not installed
automatically, you can download it — for all operating systems - follow the link:
http://www.silabs.com/products/mcu/pages/usbtouartbridgevcpdrivers.aspx
NOTE: For the "Tiny” version the driver for Windows can be downloaded here
http://www.st.com/web/en/catalog/tools/PF257938. This is latest official driver from ST company. But it was reported,
that it does not work under Windows 8. In this case, try previous version, that should work:
http://www.basecamelectronics.com/files/drivers/VCP_Setup.zip
After you have installed the driver and connected the controller with USB you will see a new virtual COM
port in the GUI in the Connection dropbox. Its name should appear upon connection.
You can connect the controller to a computer and supply power from a battery simultaneously. Again be
careful and observe polarity of battery terminals because when a USB connection is established, the in-built
reverse polarity protection is off (some versions are not equipped with such protection).
Wireless connection
To connect you can also use a wireless connection through a Bluetooth-to-Serial converter on the board
side and USB-Bluetooth adapter from the PC side (your PC may of course have built in Bluetooth). On the
board side working converters are, for example: HC-05, HC-06, Sparkfun BlueSMiRF and other Bluetooth
2.1-compatible modules. The converter should have at least 4 outputs: Gnd, +5V, Rx, Tx and it attaches to
the controller at the corresponding slot (located near the USB port) marked with UART (or Serial).
Regardless of the boards labeling the board's pins are TTL logic- not RS232.
Bluetooth module connection is shown in the Appendix B.
NOTE: Bluetooth module should be set for baud=115200 and parity=None or Even. Under None the board can be
connected to the GUI with parity set to either. However to update the board firmware through the Bluetooth
connection parity on the device must be set to Even. Working with different baud rates is possible (just change
parameter Advanced->Serial Port Speed to match module's baud rate) but some operations like realtime data
monitoring, will be slowed down, so better to configure bluetooth module. To change Bluetooth module settings, see
its manual. Starting from firmware version 2.55, there is a tool under “Board” →“Configure bluetooth...” that can
configure most popular bluetooth adapters (see Bluetooth module configuration).
Serial-over-Network (UDP) connection
This type of connection allows to configure SimpleBGC controller remotely, when it is physically connected
by UART to another device, that can communicate with the GUI over network (Wi-Fi, Ethernet, Internet).
Before connecting, you have to configure local port where GUI listens for incoming UDP messages, and
remote host and port to send outgoing messages (optional). You can do it in the “File → Settings..” menu.
The list of supported devices and detailed instructions will be published on the our web site.
Running the application
1. Attach USB cable (or, if connection over Bluetooth, pair the devices. Default password is 1234 or
0000, generally).
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1. Overview
2. Run GUI, select COM port from the list in the left corner dropbox of the main window and press
Connect.
3. When the connection to the board is established all profiles will be read and downloaded and the
GUI will display the current profile settings. You can read the board settings again any time by
pressing the READ button.
4. Make sure to have installed the latest version of firmware. To check: open "Upgrade" tab and press
"Check update". Update if a new version is available. Note that after updating the firmware you will
need to re-download the corresponding version of the GUI and revisit this connection scenario. See
section "Firmware Update" for more detailed information.
5. After you have finished editing parameters, press WRITE to save them to the persistent memory of
the controller (EEPROM). Only the current selected profile will be saved. To restore the factory
settings go to "Board" — "Reset to defaults". All the parameters of the current profile will be set to
defaults except for general settings and calibration data. In order to erase the settings of ALL
profiles, general settings and calibration data, go to menu "Board" — "Erase EEPROM".
6. To switch over to the settings of another profile, choose the desired profile from the list in the
upper right corner (dropbox labeled Profile). It is not required to read the parameters by pressing
READ. You can save different settings in 5 different profiles. Profiles can be switched over through
the GUI, by RC command, or by operating the menu button on the board. Please note that some
settings are shared by all profiles. These settings concern hardware component configuration in
particular, as well as sensor orientation and configuration, and some others. You can assign random
names to profiles. They will be saved on the board and will remain unchanged when you connect to
the GUI from a different computer.
© Basecamelectronics® 2013-2015
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2. Step-by-step setup sequence
2. Step-by-step setup sequence
1. Adjusting the mechanics
Mount the camera on the gimbal's tray and balance the gimbal in all three axes. Stabilization quality
strongly depends on balance quality. To check your balance, take the (turned off) gimbal in your hands.
Make fast motions along all axes's - try to catch any resonance point by swinging the gimbal back and forth.
If it is hard to do - gimbal is balanced correctly.
NOTE: Good balance and low friction allows reduced power levels and still keeps good quality of stabilization.
If you rewound motors by yourself, it's recommended to check electrical resistance and connectivity of your
work! With motors removed from gimbal, connect them to controller and set parameters P=0, I=0.1, D=0 for
each axis and set enough POWER. Connect main power supply. Motors should spin smoothly, while rolling
the sensor. A little jitter is normal due to magnetic force between rotor and stator (“cogging” effect).
Pay great attention to sensor installation. Its axes must be parallel with motor axes. Pay attention to
mechanical links. They must be a VERY RIGID and backlash-free. The sensor provides feedback data for
stabilization, and even any little freedom or flexibility will cause delays and low-frequency resonances. This
can complicate setting of PID and cause unstable work in real conditions (frame vibrations, wind, etc).
2. Calibrating the sensor
Calibrating Gyroscope
The Gyro is calibrated every time you turn the controller on, and it takes about 4 seconds to complete. Try to
immobilize the camera sensor as hard as you can in first seconds after powering on while signal LED is
blinking. After powering on you have 1 seconds to freeze the gimbal before calibration starts.
If you activated option “Skip gyro calibration at startup” then the gyro is not calibrated each time and the
controller begins operating immediately after powering up. Be careful and recalibrate the gyro manually if
you notice anything wrong with IMU angles.
Calibrating Accelerometer
You must perform ACC calibration only once, but it's recommended to recalibrate it from time to time or
when the temperature significantly changes. Alternatively you can make a temperature calibration through
a full range of possible working temperatures (see Temperature Sensor Calibrating).
IMPORTANT: Before processing any kind of calibration, you need to reset old values by pressing "RESET" button in
the "IMU Calibration helper" window!

Simple calibration mode: set the sensor horizontally, and press CALIBRATE.ACC button in the GUI
(or the menu button, if it's assigned to “Calibrate ACC” action). The LED will blink for 2 seconds. Be
sure not to allow the sensor to move during calibration.

Advanced mode (recommended): to begin perform calibration in simple mode as above. Then turn
sensor in order such that each side of the sensor looks up (6 positions at all, including base one). To
do this fix the sensor in each position, then press CALIB.ACC button in the GUI, and wait about 2-3
seconds (until the LED is stops flashing). You do not have to press the WRITE button at each step,
calibration data is written automatically (the data is written when the LED stops flashing for each
orientation performed).
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2. Step-by-step setup sequence
To calibrate second sensor placed on the frame (if present), select it by the toggle buttons "Camera
IMU/Frame IMU". All raw sensor data, IMU angles and all calibration commands now relates to selected
sensor.
To simplify the 6-point calibration, use the "IMU Calibration helper" tool. It will show a currently
selected position and positions that are already calibrated.
NOTE: Precise accelerometer and gyro calibration is a very important for horizon holding during dynamic flying or
YAW rotation. Its advised to use a temperature compensation to keep precise operation in a wide range of
environmental temperatures (see Temperature Sensor Calibrating).
X
Z
X
Z
X
Z
Z
Z
X
Z
X
X
3. Tuning basic settings

Connect the main power supply.

For 2-axis system, disable unused output in the “Advanced” tab, “Motor outputs” group.

Set POWER according to the motor configuration (see recommendations below)

Auto-detect number of poles and motors direction. Do not proceed to next step until proper
direction is detected!

Run auto-tuning for PID-controller, using default settings the first time.

Adjust PID controller settings if required. To check stabilization quality use the peak indicator in the
control panel (shown by the blue traces and blue numbers). Incline the frame by small angles and
try to minimize peak values by increasing P, I and D to its maximum. You may use gyro data from
the Monitoring tab to estimate stabilization quality too.
It is better to tune PID with the “Follow Mode” turned OFF for all axes.
Suggested algorithm for manual PID tuning:
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2. Step-by-step setup sequence
1. Set I=0.01, P=10, D=10 for all axes. Gimbal should be stable at this moment. If not, decrease P
and D a bit. Than start to tune each axis sequentially:
2. Gradually increase P until motor starts to oscillate (you may knock the camera and see on the
gyro graph, how fast oscillation decays). Increase D a little – it should dampen oscillations, and
decay time decreases. The lower is decay time, the better.
3. Repeat step 2 until D reaches its maximum which is when high-frequency vibration begins to
appear (you may hear it or feel it in your hands and see noisy lines on the gyro graph). When
this begins current P and D values are at maximums for your setup. At this point decrease them
a little and go to step 4.
4. Increase I until low-frequency oscillation starts. Decrease I a little to keep gimbal stable. Now
you have found a maximum for all PID values for selected axis. Repeat from step 1 for other
axes.
5. When all axes are tuned in static, try to move gimbal's frame, emulating a real working
environment. You may notice that cross-influence of axes may make gimbal unstable. In this
case, decrease a little PID values from their maximum for axes that are animating.
Good tuning results in stabilization error of less than 1 degree when you slightly rock the gimbal's frame.
Further steps to improve the precision of stabilization:
• Connect and calibrate external flight controller (see Advanced Settings, External FC Gain).
• Connect, setup and calibrate second (frame) IMU (see Second IMU sensor).
4. Connecting and configuring RC
•
Connect one of the free receiver's channels to the input labeled as “RC_PITCH “, observing the
correct polarity
In the RC Settings tab:
•
Assign “RC_PITCH - PWM” input to PITCH axis.
•
Leave all other axes's and CMD's as “no input”.
•
For PITCH axis, set MIN.ANGLE=-90, MAX.ANGLE=90, ANGLE MODE=checked, LPF=5, SPEED=50.
•
Connect the battery to the main controller and receiver, and check that RC_PITCH input receives
data in the “Monitoring” tab (slider should be blue filled and reflects stick movement).
Now you can control the camera from your RC transmitter, from -90 to 90 degrees. If you are not satisfied
with the speed of movement, adjust the SPEED setting. If stick need to be inverted, select the INVERSE
checkbox.
If your RC stick have neutral position, better to select the SPEED mode to have better control compared
with the ANGLE mode.
Connect and tune remaining axes the same way, as required. You have 5 PWM inputs to assign to all axes
and to the “command” channel.
5. Testing gimbal in real conditions
For flight on multi-rotors, connect controller to the GUI and turn ON the vehicle's motors, holding it above
your head (and away from your face and hands). Check the vibrations on the camera by using the
Monitoring tab / ACC raw data. Try to decrease the level of vibrations using soft dampers on gimbal's mount,
balancing propellers, and so on.
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2. Step-by-step setup sequence
NOTE: Brushless motors versus traditional servos provide faster reaction, but less torque. That's why it's hard for
them to fight against wind and air flows from props. If you are developing multi-rotor frame try to avoid these
influences (for example, lengthen arms a bit, or tilt motors away from the center or place the camera above props in
case of H-frame). Also bear in mind, when copter moves with high speed, an air flow is deflected and this affects the
gimbal as well.
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3. The Basecam GUI overview
3. The Basecam GUI overview
GUI Structure
The GUI contains different functional blocks:
1. A configuration block in the central part of the window, organized by ‘tab’:

Basic – Basic gimbal stabilization settings. Adjusting these settings is usually adequate to
achieve good camera stabilization.

Advanced — More precise tuning options.

RC – settings to control the gimbal roll/pitch/yaw orientation with RC inputs.

Service – Specify the behavior of the MENU button (located on the controller board or mounted
externally) and tune the battery monitoring service.

Follow – settings related to special mode of the camera control when it follows the frame.

Monitoring — real-time sensor data monitoring. This screen is extremely helpful in tuning your
gimbal performance. Firmware Update — Firmware and GUI software versions and update
options.

Upgrade – lets you to check the version of firmware and upgrade if necessary.
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3. The Basecam GUI overview

Filters – settings to setup digital filters for PID controller.

Adj.vars – you can change many system parameters on-the-fly by remote controller or joystick

Analyze – system analysis tool

Scripting – you can write user scenarios, load to EEPROM and execute by remote command.
2. Connection — COM-port selection and connection status.
3. Profile — Profile selection, loading, re-naming, and saving.
4. Control Panel — graphic visualization of gimbal orientation angles in three axes.

Black arrows are displaying the angles, blue arrows are a 10x time magnification to provide higher
precision. Red marks show target angles that gimbal should keep.

Thin blue lines shows the maximum (peak) deflection from the central, neutral point.

Blue digits show peak deflection amplitude. Using these numbers, stabilization quality can be
estimated.

Vertical red bars to the right of the scales show actual power level from 0 to 100%.

Gray arrows shows the angle of a stator of each motor, if known.
5. READ, WRITE buttons are used to transfer setting from/to board.
6. MOTORS ON/OFF button is used to toggle motors state.
7.
At the bottom of the screen, tips, status or error messages (in red color) are displayed . Overall
cycle time and I2C error count is also displayed.
8. Battery voltage indicator with warning sector.
Board menu
This menu encapsulates options to Read/Write settings (duplicating READ, WRITE buttons) to calibrate
sensors, to reset parameters to their default values, or to completely reset board by erasing EEPROM.
Language menu
The GUI starts in the English version of the user interface. To change the interface language, choose the
one desired in the 'language' menu and restart the program.
View menu
You can change a visual theme from the “View” menu. For example, when using GUI outdoor, better to
switch to one of the high-contrast themes.
Further in this manual each tab is described in details. At the end of this manual, you can find additional
step-by-step tuning recommendations.
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4. Basic Settings
4. Basic Settings
PID and Motor settings

P,I,D – PID regulation parameters for all axes.
◦ P – describes the power of disturbance response. Higher values means a stronger response
reaction to external disturbance. Raise this value until the stabilization quality of fast
disturbances will be adequate. If the “P” value is too high, oscillations of the axis will start to be
present. These oscillations will get worse if there are vibrations that reach the IMU sensor
board. If oscillations occur, raise the “D” parameter by 1 or 2 units, and then try to raise the “P" value
again.
◦ D – The “D” value reduces the reaction speed. This value helps to remove low-frequency
oscillations. A “D” value that is too high can cause high-frequency oscillations, particularly
when the IMU sensor is exposed to vibrations. In special cases, it may be filtered out by digital
filters (see below).
◦ I – The “I” value changes the speed at which the gimbal moves to incoming RC commands and
to move the gimbal back to neutral. Low values result in a slow and smooth reaction to RC
commands and to getting back to neutral. Increase this value to speed up the movement.

POWER – maximum voltage supplied to the motors (0 - 255, where 255 means full battery voltage).
Choose this parameter according to your motor characteristics. Basic tuning:
◦ Motors should not get too hot! Motor temperatures of over 80С will cause permanent damage to
motor magnets.
◦ A Power value that is too low will not provide enough force for the motor to move the gimbal
and stabilize the camera adequately. A low power value will be most noticeable in windy
conditions, when the gimbal is not well balanced, or if the gimbal suffers from mechanical
friction. Slowly lower the Power parameter to find its optimal value. Find the lowest value that
still provides good stabilization and adequate holding torque.
◦ Raising the power equals raising the “P” and “D” value of PID settings. If you raise the POWER
value, you should re-tune your PID values as well.

“+” - Additional power that will be add to the main power in case of big error (caused by missed
steps). It helps to return camera to the normal position. If main power + additional power is greater
than 255, the result is limited to 255.

INVERT – reverse motor rotation direction. It's extremely important to choose the correct motor
rotation direction before tuning other parameters! To determine the correct direction, set the POWER
value big enough to rotate the camera. Level the camera tray horizontally and click the AUTO
button in the "Motor configuration" settings. The gimbal will make small movement to determine
correct motor rotation direction. Wait for the calibration procedure to complete. Then, re-set your
PID values and tune your POWER values.

NUM.POLES – Number of motor poles. This value needs to be equal to the number of magnets in
your motor’s bell. During the “auto” calibration process described above, this value is automatically
detected. However, this value is sometimes not correctly determined during the “auto” calibration
process and will need to be verified and possibly corrected manually. Count your motor magnets
and enter this value if the value is not correct in the GUI.
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4. Basic Settings
Main IMU sensor
Note: Before tuning your controller, install the camera into the gimbal firmly and ensure your gimbal is balanced,
i.e. each motor's axis passes through the center of gravity of its load.
Specify your IMU sensor board’s orientation and position on the gimbal . For a standard IMU sensor
installation, look at the gimbal from behind just like the camera will view out from the gimbal. Viewing the
gimbal in this way, the UP and Right direction will match the Z and X axis. You can place the IMU sensor in
any direction, keeping its sides always parallel to the motor axis (be very accurate here, it is very important
to precisely align the sensor and mount it firmly). Configure your IMU orientation in the GUI, by specifying
axes direction in the “Top” and “Right” dropboxes, or using AUTO button to find proper direction
automatically in 3 simple steps. The correct configuration should result in the following:
▪ Camera pitches forward – the PITCH arrow spins clockwise in the GUI.
▪ Camera rolls right - ROLL arrow spins clockwise in the GUI.
PITCH
▪ Camera yaws clockwise - YAW arrow spins clockwise.
✔
ROLL
◦ Skip Gyro calibration at startup - With this option, the board starts working immediately after
powering it on, using the saved calibration data from last gyroscope calibration call. However,
stored calibration data may become inaccurate over time or during temperature changes. We
recommend that you re-calibrate your gyro from time to time to ensure the best performance.
As an alternative, you can perform a temperature calibration (see Temperature Sensor Calibrating).
Second IMU sensor
There is an option to install the second IMU sensor on the gimbal's frame. The advantage is more precise
stabilization (you may use lower PID's to get the same quality) and knowing frame
tilting greatly helps 3-axis systems to extend the range of working angles.
The second IMU should be connected to the same I2C bus as main (in parallel).
Sensors should have different I2C-address (Main IMU – 0x68, Frame IMU – 0x69).
On the original Basecam IMU sensor, address 0x69 may be set by cutting the ADDR
bridge, located on the back side of the sensor.
◦ Swap frame and main sensors – swap the roles of IMU sensors.
Mounting the Frame IMU
There are two options where to place the second IMU: below YAW motor and above it. In case of 2-axis
stabilization, there is only one option – above ROLL motor.
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4. Basic Settings
Frame IMU:
above YAW
YAW
MOTOR
below YAW
(above ROLL)
ROLL
MOTOR
PITCH
MOTOR
Camera IMU
If the sensor is placed above YAW motor, it helps to stabilize ROLL, PITCH and YAW motors. But the system
becomes less stable during long work (because the frame heading, estimated from the second IMU, may
drift with time and auto-correction may not work in all cases).
If the sensor is placed below YAW motor, it does not help YAW axis stabilization, but its operation is more
reliable. There is a particular option you can choose for this position from: "Below YAW + PID source". It
means that if Frame IMU is mounted below YAW motor it can be used as a data source for the PID
controller. In some cases this can give better result than the main IMU, because mechanical system's “IMUMotor” becomes more stiff when its length is shorter and its closed-loop operation becomes more stable.
Like the main (camera) IMU, the frame IMU may be mounted in any orientation, keeping its axis parallel
with the motor's axis.
Configuring the frame IMU
To configure the frame IMU, first of all set its location in the “Advanced” tab, “Sensor” area. Write settings to
the board and go to the “Basic” tab. Press the button “Frame IMU”:
If the second IMU is connected properly, this button becomes active. After pressing on it, all IMU settings
now affect the frame IMU. You may notice the right panels with arrows are displaying now angles not for
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4. Basic Settings
the main, but rather for the frame IMU. Also, in the “Monitoring” tab, accelerometer's and gyroscope's data
are for the frame IMU.
Change sensor orientation (axis TOP, RIGHT) and write setting to the board if necessary (board will be
restarted). After restart, calibrate the accelerometer and gyroscope like you did for the main IMU. For the
accelerometer you can do simple calibration or extended 6-point calibration. But for the second IMU,
precise calibration is not so crucial, as for the main IMU.
Precision of angle measurement
A MEMS gyroscope-based IMU gives very good precision, especially compared to single accelerometer. But
it still can be affected by environment, that can reduce the precision and give negative effects like lost
horizon, slowly drifting angles, cross-axis interference (rotation by one axis lead to declination by other
axis). Below are the most common reasons and our recommendations how to solve them:
• Vibrations: try to isolate gimbal from vibrating platform by dampeners.
• Lateral or centrifugal accelerations (fast accelerated slides or movement by a curved trajectory):
consider “Gyro trust” setting.
• Wrong calibration of accelerometer or gyroscope: carefully follow our instructions and check the
validity of calibration from time-to-time.
• Misalignment of sensor's axes and gimalbal motor's axes: pay attention to sensor orientation when
mounting sensor on the gimbal.
• Changes in temperature than affect calibrations: do the temperature calibration
• Drift of heading angle without good reference: install and configure a magnetometer sensor.
• Over-saturation of gyro sensor: prevent rotations faster than 2000 degree/second.
The problem of mutual azimuth drifts of two IMU sensors
Gradual drift of angles taken from Gyro is a normal situation, and you need to take into account it in any
AHRS (attitude and heading reference systems). Additional sensors can be used to correct gyro drift: an
accelerometer and magnetometer.
An accelerometer corrects 2 axes of a gyro by gravitation vector.
A magnetometer corrects 3rd axis by Earth's magnetic field vector.
Complete IMU generally includes 3 sensors (called 9-axis system). Using a magnetometer in gimbals is not
very common since the precision of a magnetometer highly depends on the environment and it is difficult
to calibrate it properly. Fortunately, in the most cases of gimbals usage, the absolute precision of the
azimuth detection is not required. But using two IMUs (first installed on the camera tray, and second
installed on the frame of a gimbal), the azimuth of one sensor has to match the azimuth of another sensor.
In the SimpleBGC32 controller, special algorithms are used to correct mutual azimuth drift. It allows the
system to work stably in almost any conditions.
The following are methods which are automatically applied by the controller to correct absolute drift and
mutual azimuth drift of both sensors:
The limits caused by a gimbal’s design. For example, if the second sensor is installed below YAW, its
azimuth in normal position always match the azimuth of the first sensor. But when the frame
inclined forward at 90 degrees, this condition is wrong and other methods should be used.
• Detecting rotation of motors by the electric field. If the second sensor is installed above YAW, its
azimuth may not match the azimuth of the first sensor. But if the rotation angle of YAW motor is
known, it is possible to match their azimuths. In the different orders of hardware axes, for example,
Cam-YAW-ROLL-PITCH, this situation appears in any position of the second sensor. Note that this
correction works if motors are switched on, and system was started in “normal position” when
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•
4. Basic Settings
•
•
•
•
azimuths of both sensors were matched (though additional algorithms are used to synchronize
azimuths, its better to always take care about proper start position).
Detecting rotation of motors by encoders. Using encoders (at least one installed on YAW axis)
significantly improves the precision of correction.
Using magnetometer. If a magnetometer is connected to the IMU sensor (frame or camera) then its
azimuth will match True North. The second sensor will be automatically corrected by the
magnetometer by one of the above methods.
Using precise orientation data from an external AHRS system. Using Serial API, you can provide the
precise orientation of the camera tray or a frame measured by an external system with high-grade
IMU. In this case, an appropriate sensor will be corrected using this data, and the second sensor will
be corrected by one of the above methods.
Using AHRS data from flight controller - you can connect UAV autopilot (for example, Ardupilot or
Naza) to the SimpleBGC32 controller by MavLink protocol, to synchronize their attitudes.
Temperature Sensor Calibrating
If the gimbal will be used in a wide temperature range, it is necessary to perform what is called a
temperature calibration of the accelerometer and gyroscope. We suggest you do this procedure once
properly for at least the temperature range you will be using the gimbal at. This will eliminate the need to
repeat calibration due to each change of ambient temperature and results in increased stabilization
accuracy for operation within the calibrated temperature range.
Temperature calibration is done through a computer connection with the use of the calibration assistant or
offline by setting the corresponding commands for the board's menu button.
Calibration with the use of GUI is described below. Offline calibration is carried out similarly.
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4. Basic Settings
Regular calibrating
was accomplished
How many measurements
were collected for each of
6 positions
Current position
Start button of
regular
calibrating
Choose sensor for
calibration
Start button of
temperature
calibrating
Current sensor
temperature
Range of temperatures in which
temperature calibrating was
preformed
Temperature Calibrating Assistant
During temperature calibration it is important to ensure the slowest possible variation of sensor
temperature so that all its parts have the same temperature. In order to ensure this condition the sensor
can be protected by a heat insulating shell cut out of a piece of plastic foam. EPP foam or something similar
is best- its common in high quality packaging (you will likely recognize it from the picture).
It is better to realize it in the form of a parallelepiped and align the sensor in accordance to its sides — this
will make accelerometer calibration considerably easier.
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4. Basic Settings
Thermal insulation of the sensor
Temperature accelerometer calibrating
Calibration assignments are made for three values of temperature, starting with the lowest. The 6-position
calibration is performed for each (of 3) temperature(s). The process is the same as for 6-point calibration,
but you need to press the temperature calibration button instead of the usual calibration button. The steps
should not be less than 10 degrees Celsius. For example, if the first six calibrations were carried out at
-10°С, the next calibration series should be realized at a temperature not lower than 0°С.
Temperature accelerometer calibration procedure:
1. Connect to GUI, run "IMU calibration helper" tool.
2. Select a sensor (on the camera or on the frame).
3. Reset the previous calibration by pressing RESET and let it restart.
4. Cool the sensor to necessary temperature (for example, by placing it in a freezer), connect to GUI
again, run calibration wizard and select the sensor. Check the current temperature indication of the
sensor.
5. Calibrate in each of the six positions in a random order. Insignificant temperature variation is
allowed during position switching, but it is desirable to realize the series as quickly as possible.
Thermal insulation will help to slow down the sensor heating.
6. Make sure that each calibration (series) done is indicated by a new thermometer icon in a
corresponding slot. If the difference to the previous calibration temperature value is less than 10
degrees, the new value will not be accepted and error will be indicated by the system with a
flashing LED indicator.
7.
Repeat steps 4, 5, and 6 for each of the higher temperature values so that the whole sensor
working temperature range is covered.
8. Calibration results check: Accelerometer maximum values in each of the 6 directions are equal to
1G throughout the whole temperature range.
When the calibration assistant shows 18 thermometer icons, the checkbox for "Accelerometer temperature
compensation" will switch on.
NOTE: Starting from firmware version 2.56, regular calibration by 6 points does not disable the temperature
calibration, but updates it to match the actual values at the current temperature. So, while the temperature
compensation is being always active, you can from time to time make a regular calibration to improve its precision.
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4. Basic Settings
Temperature gyroscope calibration
The gyroscope is calibrated under continuous temperature increase; the sensors of the frame and the
camera are calibrated simultaneously. Choose the calibration temperature range so that the intended
working temperature range for the gimbal is covered.
Temperature gyroscope calibration procedure:
1. Cool the sensors down to the required temperature below zero (for example, by placing them into a
freezer), then put them in a place with high temperature above zero and secure. Provide total
immobility (hold them perfectly still) and good thermal insulation. It is necessary to ensure slow
uniform sensor heating to accomplish a sufficient amount of measurement.
2. Connect the controller to the GUI and run the calibration helper. Check current temperature
indication of the sensor.
3. Press the “TEMP. CALIB” button in the Gyroscope group. You can also start temperature calibration
by pressing a hard button in menu or through the menu item: Board -> Sensor -> Calibrate
Gyroscope (temp. compensation).
4. During calibration the green LED indicator is flashing slowly. Calibration continues as long as
temperature increases. Ensure total immobility of the sensors during whole calibration process!
5. As soon as the temperature stops rising, calibration is automatically finished and the board is
restarted so that new parameters can be applied. The checkbox "Gyroscope temperature
compensation" switches on.
6. Calibration results check: gyroscope raw data in the "Monitoring" tab when totally immobile equals
to zero within the whole temperature range applied during calibration; drifting of axis arrows is
absent or very low.
NOTE: Starting from firmware version 2.56, the regular gyro calibration does not disable the temperature
calibration, but updates it to match the actual values at the current temperature. So, while the temperature
compensation is being always active, you can sometimes make a regular calibration to improve its precision.
If gyroscope calibration at system start is enabled, it will refine the temperature compensation, but not save it to the
EEPROM memory.
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5. PID auto-tuning
5. PID auto-tuning
This feature will be helpful for beginners who often experience difficulties with PID tuning.
Before you start automatic tuning, its very important to properly configure the hardware of your system:
motor outputs, “Power”, “Inverse” and “Number of poles” (latest 2 settings may be detected automatically, as
described in the user manual). Also, main IMU position should be configured and accelerometer and
gyroscope should be calibrated.
Plug-in a battery, connect board to the GUI and press the “Auto” button in the PID parameters section. You
will see a dialog window, where you can setup the auto-tuning process:
The slider at the top defines the target of tuning. If its close to “Better precision”, it will try to achieve
maximum gain and keep it. If close to “better stability”, it will find maximum gain and then decrease it by
30-50% to make the system more stable.
You may chose which axis to tune. Best results may be reached only if you tune each axis separately. But for
the first run, you can tune all axis at the same time.
If you want to use your current settings as start point, select “Start from current values”. Otherwise values
will be set to zero in the beginning.
Select “Send progress to GUI” checkbox to see how PID values change in real-time during tuning process.
Select “Log to file” to write PID values together with some debug variables to the file “auto_pid_log.csv”. It
may be analyzed later to better understand system behavior. There are a number of tools to plot data from
log files, for example http://kst-plot.kde.org
How does it work?
The tuning process does a simple job: it gradually increases P,I,D values until system enters in selfexcitation state. Self-excitation means maximum possible gains are reached. Then it rolls back values a bit
and repeats the same iteration 2 times. Averaged “good” values are stored as PID settings.
During the process, you should firmly hold the gimbal in your hands. You can place it on a support but
check that it provides strong hold, not less than your hands.
After about a minute of work, you can see that PID values have grown big enough and camera is stabilized.
Now you can slightly tilt handles in all directions to emulate real-usage conditions. At this point try to find
a point where self-excitation occurs (at some particular orientation of the gimbal motions tend to cause
self-excitation), and continue tuning system in this point (starting with the “worse case” position).
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5. PID auto-tuning
It is normal that the gimbal starts to vibrate when PID values come close to their maximum. If any motor
looses sync due to strong oscillations, you can help to restore it by hand without interrupting the process.
In some cases, you can get a better result (i.e. higher PID gains) if you remove high-frequency resonances
before starting automatic tuning. See section “Digital filters” for more details.
The boards LED is flashing during the tuning process. When the process finishes its job the LED will light
ON and new PID settings will be transferred to the GUI.
There is also a corresponding menu command that can start PID auto-tuning without connection to the PC.
Adaptive control of PID gains
This settings group lets to adaptively decrease PID gains when the system becomes unstable due to high
PID gains. For example the system may be tuned very well for certain positions, but it may become
completely unstable in different position. Self-excitation may cause strong vibration that may negatively
affect gimbal construction and may even become hazardous for the camera. For gimbals that have this
problem a possible workaround is to use adaptive PID control (another possibility is to change the physical
characteristics of the gimbal or its load, improve its balance or employ counter-balances etc) explained as
follows.
•
RMS error threshold, 0..255 - RMS (root mean square) error state variable effectively shows the
level of vibrations. When it exceeds this threshold, adaptive PID algorithm comes into action.
Recommended value is 10..15.
•
Attenuation rate, 0..255 - the more this value, the more PID gains are decreased. Choose this value
big enough to quiet system quickly. Effect of different rates is shown on the picture:
•
Recovery factor, 0..10 - defines, how fast PID gains are recovered back when the system becomes
stable. Too low of a value may increase a chance that vibration comes back in a short time. Too high
of a value may cause worsen of operation (because lowered PID values are kept longer).
Recommended value is 5..6
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6. RC Settings
6. RC Settings
The SimpleBGC board provides very flexible configuration of a remote controller. It supports up to 5 digital
inputs, including one that supports most popular serial protocols, and 3 analog inputs. It can also output an
RC signal in pass-through mode or by Serial API commands. The full RC routing diagram can be found in
the Appendix C of this manual.

RC Input Mapping – here you can assign hardware RC inputs to target control channels. There are 5
hardware digital inputs provided on the board for RC Radio control connections and 3 analog
inputs for connecting a joystick. Each input can be assigned to control any of three channels, one
for each axes, and one command channel. If control for an axis is not needed, leave the option at
"no input".

RC_ROLL pin mode – Assigns format for the incoming signal on RC_ROLL pin:
◦ Normal – incoming signal is in the PWM format which most RC-receivers generally output.
◦ Sum-PPM - some receivers have this signal output format option. It is a PWM format
modification, in which every channel transmits sequentially through one cable. In this case you
do not need to connect other channels (read your receiver's user manual to check if it has
SumPPM out- how to configure it to do this and which output (channel) it uses).
◦ Futaba s-bus – receivers made by Futaba may transmit data in a special digital format, up to 16
channels by one wire. Connect it to RC_ROLL pin.
◦ Spektrum – another digital multi-channel protocol, that is used to communicate Spektrum's
satellite modules with the main module, and in its clones. There is a dedicated socket on the
board (marked Spektrum) that matches the standard connector.
Starting from firmware ver. 2.43b7, you can bind a satellite (remote) receiver connected to the
“spektrum” port, directly from the SimpleBGC board. It will be bound as the stand-alone
(master) unit. To start binding assign action “Bind RC receiver” to the hardware menu button
and execute this action, or execute the same action from the “Board – Execute command” menu
in the GUI. You can select any of 4 different modes prior to start binding, in the “RC” – “Other
settings” tab:
▪ DSM2/11ms
▪ DSM2/22ms
▪ DSMX/11ms
▪ DSMX/22ms
Choose a mode that a combination of your transmitter and receiver supports (10- or 11-bit
modification does not matter at this moment). Switch to Auto-detection mode after binding is
done. If channels are read incorrectly, select 10bit or 11bit modification manually.
◦ SBGC Serial API 2nd UART – in this mode, RC_ROLL input can handle Serial API commands. It
lets us expand the board functionality by connecting external devices, implementing SBGC
Serial API protocol. If RC_YAW pin is not occupied, it acts as TX pin of this UART, allowing to use
bi-directional communication. If RC_YAW pin is occupied, only RX functionality is possible (in
other words, external device can send commands to the board, but can't read answers).
Port settings: 115200 baud, 8N1 or 8E1 - 1 stop bit, 8 data bits, parity 'none' or 'even' (auto-detected after
several incoming commands).

For each control target you can choose appropriate hardware input from the drop-down list.
◦ RC_ROLL, RC_PITCH, RC_YAW, FC_ROLL, FC_PITCH – are the hardware inputs on the board that
accept a signal in the PWM (Pulse Width Modulation) format (excepting RC_ROLL, see above).
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6. RC Settings
Most RC receivers output this signal type.
◦ ADC1, ADC2, ADC3 — dedicated analog inputs, marked on the board as A1, A2, A3 and accepts
analog signals in the range from 0 to +3.3 volts. For example, joystick variable resistor provides
such a signal. Connect A1..A3 to the center contact of variable resistor, +3.3V and GND to side
contacts. See Connection Diagram for more info.
◦ VIRT_CH_XX – In case of RC_ROLL pin mode is set to multi-channel signal format, you can
chose one of the virtual channels.
◦ API_VIRT_CH_XX – Additional channels that may be set by Serial API command.

Control targets:
◦ ROLL, PITCH, YAW - controls the position of the camera
◦ CMD allows you to execute some actions. You can configure a 2- or 3-position switch on your
RC transmitter for a specified channel, and assign it to the CMD channel. Its range is split into 3
sections : LOW, MID, HIGH. When changing the position of your RC-switch, signal jumps from
one section to another and the assigned command is executed. The full list of available
commands is described in the section “MENU BUTTON” of this manual.
◦ FC_ROLL, FC_PITCH – is used to mark any of PWM inputs to be a signal from the external flight
controller. See “External FC gain” section for details.

Mix channels - you can mix 2 inputs together before applying to any of ROLL, PITCH or YAW axis. It
provides control of the camera from the 2 sources (joystick and RC for example). You can adjust the
proportion of the mix from 0 to 100%.

ANGLE MODE — RC stick will control the camera angle directly. The full RC range will cause a
camera to go from min to max angles, as specified above. If RC stick doesn't move camera stands
still. The speed of rotation depends on the “SPEED” setting and the acceleration limiter setting.

SPEED MODE — RC stick will control the rotation speed. If stick is centered- camera stands still, if
stick is deflected, camera starts to rotate, but does not exceed min-max range. Speed of rotation is
proportional to stick angle and the SPEED setting. RC control inversion is allowed in both of control
modes.

INVERSE – Set this checkbox to reverse direction of rotation relative to stick movement.

MIN.ANGLE, MAX.ANGLE – range of the angles controlled from RC or in the Follow mode. For
example, if you want to configure a camera to go only from a leveled position to down position, set
min=0, max=90. To disable constraints, set min=max=0. For ROLL and PITCH axis angles are
absolute (i.e. relative to ground) for both “Lock” and “Follow” modes. For YAW axis limits are not
applied in the “Lock” mode, and are applied relative to frame in the “Follow” mode. For example, if
you set min=-30, max=+30 for YAW in the “Follow” mode, you will be limited by the range +-30
degrees relative to frame when controlling camera from RC sticks or joystick, and not limited when
controlling camera by the rotation of frame.

LPF – Signal low-pass filtering. The higher the value is, the smoother the reaction is to stick
commands. This filter cuts fast stick movements but adds some delay as a consequence.

INIT.ANGLE – if RC control is not configured for any axis (or there is no signal on the source) the
system will keep initial angle specified in this field. System will start with these angles in SPEED
mode.
◦ Do not update initial angle – set this option to not update the initial angles in the EEPROM
after executing "Set tilt angles by hands" menu command or "Swap RC PITCH - ROLL", "Swap RC
YAW-ROLL" commands. If not set, system will start with the new initial angles next time.
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6. RC Settings

RC Sub-Trim – correction for transmitter inaccuracy.
◦ ROLL, PITCH, YAW trim – central point trimming. Central point here is PWM 1500. It's better to
trim it in the transmitter. But in case of it is not possible (when using joystick, for example), you
can use AUTO function in the GUI. Just place stick in neutral position, and press AUTO button.
Actual data becomes new center point. Press WRITE button to apply settings.
◦ Dead band — adjusts dead band around the neutral point. There's no control while RC signal is
inside this range. It helps to achieve better control by eliminating jitters from unintended
movement of the stick around neutral point. This feature works differently in SPEED and ANGLE
modes: in the SPEED mode, dead band is created around neutral point, in the ANGLE mode,
dead band tracks stick position, and small jitter in this position is eliminated.
◦ Expo curve – adjusts the curvature of an exponential function. Applying more expo means that
movements around the center are slower (more precise) but movements of larger values are
much greater- with the two extremes transitioning from one to another 'exponentially'. This
gives precise control from RC in the range of the small values but rough and strong control
near endpoints. Works only in SPEED mode.

Limit Accelerations - this option limits angular accelerations in case of hard RC or “Follow” control
(useful to prevents jerks or skipped steps, smoother camera control, less impact on the multirotor's
frame). The lesser the value is the smoother the camera rotation under control is.

PWM Output – a mapping that allows you to pass any virtual channel, decoded from serial input
signal, to special pins that can output PWM signal. This signal can be used to drive a hobby servo
or IR remote camera trigger, for example. On the SimpleBGC 3.0 boards, these pins share PWM
output function with other functions:
Servo1 – FC_ROLL
Servo2 – FC_PITCH
Servo3 – RC_PITCH
Servo4 – AUX1
To enable servo output on any of these pins, make sure that its not specified as RC input in the GUI.
This feature may be useful if you connect RC receiver by single wire and want to decode signal to
the separate PWM channels to connect other RC-controlled devices.
When connecting regular hobby servo to these ports, there are two options to get +5V to supply
them:
◦ Connect external power (for example from +5V BEC) to the central pin of any of RC inputs. and
cut (de-solder) jumper J1 that passes 5V from internal voltage regulator to them.
WARNING: two power sources joined together, will likely burn each other out because a switching DC converter
is used to provide 5V supply for the board and it may conflict with the external power source.
◦ Close (solder) jumper J1 and get +5V from internal voltage regulator.
WARNING: before connecting servos, check their total maximum current rating, and compare it with the current
rating that the board can provide on the 5V line (you can find it in the hardware specifications of the board, for
regular “Basecam SimpleBGC 32bit” the version is 1A).
Order of Euler angles
The control of the gimbal from RC transmitter or joystick is made by 3 separate angles (called “Euler
angles”): ROLL (to control horizon), PITCH (to tilt up-down), and YAW (to turn left-right). To rotate camera
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6. RC Settings
from one direction to another, we can make three separate rotations by three axes. But the order of
rotations plays a role. You can change the order of rotations in the parameter “Order of Euler angles”. The
difference is displayed in the picture below:
YAW 360°
YAW 360°
PITCH
360°
PITCH
±90°
ROLL
360°
ROLL
±90°
CAMERA-ROLL-PITCH-YAW
CAMERA-PITCH-ROLL-YAW
Order of Euler angles
The default order is “Camera → PITCH → ROLL → YAW → Frame”. As you can see, it does not allow to roll
camera to angle greater that ±90 degrees, because in this case PITCH axis becomes equal to YAW axis and
the PITCH angle can not be distinguished from the YAW angle. Its recommended to set Min.angle=-85,
Max.angle=85 for ROLL axis in the “RC” tab, to not allow this case.
In opposite, if you select order “Camera → ROLL → PITCH → YAW → Frame”, you can roll camera to any angle
(including infinite 360 degree rotation), but can not pitch it more than ±90 degrees. The same, setting
Min.angle=-85 and Max.angle=85 for PITCH will help to prevent entering forbidden area.
NOTE: This setting is profile-based. It means that you can assign different Euler order to different profiles and switch
between them on-the-fly by menu button. Stabilization will be not interrupted.
"Cam – YAW – ROLL – PITCH" - This order of the axes is
needed for special cases when you need to point the camera
to a certain point on a ground and hold it at all pan and tilt
angles of a frame. In a typical case, the stabilization axes
PITCH and ROLL are rotated together with the rotation of the
camera (or a frame) by YAW axis. This means that if the
camera is looking down at a certain ROLL and PITCH angle,
and you pan the camera (or a frame in 2-axis system) - its
optical axis draws an arc, ie not locked to a point. If you
choose the order of the Euler angles "YAW-ROLL-PITCH", the
optical axis of the camera is always locked to a point on the
© Basecamelectronics® 2013-2015
YAW
ROLL
PITCH
PITCH
MOTOR
ROLL
MOTOR
28
6. RC Settings
ground regardless of the evolutions of a frame and YAW rotations of a camera. This mode is suitable for 2axes gimbals mounted on a gliders with the camera pointed down.
NOTE: the RC control in space of Euler angles by ROLL and PITCH axes is no longer tied to the orientation of the
frame, but is linked to the Earth. It means that when you turn the camera by 90 degrees left or right, ROLL becomes
PITCH and visa versa. Also, you must use a magnetometer to prevent a drift of the internal coordinate system relative
to the Earth, caused by the drift of the gyroscope.
"Cam – PITCH(L) – ROLL – YAW(L)",
"Cam – ROLL – PITCH(L) – YAW(L)"
In this mode ROLL axis is always linked to horizon (locked), but
PITCH and YAW axis matches the corresponding motor's axes.
Camera orientation is not linked to the ground anymore (and not
described by the Euler angles), but still can be controlled from RC
or in the "Follow" mode. This mode can be used to build 2-axis
gimbal where ROLL motor is linked to camera and stabilized
relative to ground, and PITCH motor is linked to boom and can
work in any position on 360-degrees circle in "Follow" mode to
stabilize random short rotations of a boom, but follow long
rotations.
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CAMERA
ROLL
MOTOR
PITCH
MOTOR
29
7. Follow Mode Settings
7. Follow Mode Settings
Follow Mode is a special control mode that makes the camera “follow” a movements of the outer frame, but
at the same time eliminates small frame jerking. Several modes of this operation are possible:
•
Disabled – camera is locked to ground and may be rotated only by RC or joystick.
◦ Estimate frame angles from motors - this uses the motor's magnetic field for rough estimation
of frame tilting, and helps to increase the range of the frame angles where the gimbal's
operation is stable. For proper operation in this mode, it is strictly required to calibrate Offset
setting (see below). Like with the Follow mode, its not recommended to use this option in
flight, it is dedicated for hand-held systems only.
NOTE: This option is ignored if you connect second IMU, mounted on the frame, or use encoders, because the
data from these sources is more precise than from motors.
•
Follow Flight Controller – camera is controlled from RC together with the mixed signal from an
external flight controller (FC). Almost every FC has servo outputs to drive a gimbal. It feeds the
information about the aircraft's angles to these outputs in the PWM format (that servos use).
SimpleBGC can get this information and use it to control a camera such way that it tracks the
tilting of aircraft. It is necessary to connect and calibrate the external flight controller (see EXT.FC
GAIN settings). After calibration you can setup the percentage values for ROLL and PITCH in which
the camera will follow frame inclinations.
•
Follow PITCH, ROLL – this mode is dedicated to hand-held systems. FC connection is not required.
In this mode, the position of the outer frame by PITCH and ROLL is estimated from the motor's
magnetic field. This means that if motor skips steps, position will be estimated incorrectly and
operator should correct camera by hands, returning it to proper position.
WARNING: you should use this mode carefully for FPV flying, because if the camera misses its initial direction, there is
no chance to return it back automatically. But if encoders are used, this is not a problem.
◦ Follow ROLL start, deg. - Set the angle (in
degrees) of the camera PITCH-ing up or down,
where the ROLL axis enters follow mode. Below
this angle, ROLL is in lock mode.
◦ Follow ROLL mix, deg. - Set the range (in
degrees) of the camera PITCH-ing, where the
ROLL axis is gradually switched from the 'lock'
mode to 'Follow' mode (see picture)
ROLL axis mode
locked to the
ground
soft transition
angle of the camera
inclination by PITCH
follow frame
HINT: To completely disable follow for ROLL, set these values to (90, 0). To permanently enable follow for ROLL
(regardless of the camera PITCH-ing), set values to (0, 0).
•
Follow YAW – the same as above, except it can be enabled only for YAW axis. For example, you can
lock camera by ROLL and PITCH axis by selecting “Disabled” option, but still control camera by YAW
by enabling “Follow YAW” option.
There are additional settings to tune follow mode:
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7. Follow Mode Settings
•
Dead band, degrees: you can set a range where the rotation of an outer frame does not affect the
camera. It helps to skip small jerks when you operate gimbal by hands.
•
Expo curve: when the expo curvature parameter is greater than zero, a small or medium
declination of an outer frame from neutral allows makes only very fine control. But the strength of
control exponentially grows when angles of declination become greater (up to ±45 degrees). This
feature gives considerable freedom in camera operation, from fine and smooth control to very fast
movements.
•
Follow rate inside dead-band – very soft control to always keep camera in the center of the dead
band. Set it to 0 to disable this feature.
•
OFFSET: this is a setting that allows you to properly configure the exact initial position of the
gimbal. For YAW axis it allows fine adjustment of the camera heading relative to a frame heading.
For PITCH and ROLL axis there is an option to calibrate offset automatically. To do this power on
the system, hold frame leveled and press AUTO button. Don't forget to write setting when finished.
If the camera after power on is not leveled, you need to adjust the offset setting.
✔
•
SPEED - adjust the speed of the camera rotation. Don't set big values that motors can not handle (if
motor does not produce enough torque to move the camera, it will skip steps and synchronization
will be broken). In this case an acceleration limiter may help to have high speed but not to miss
steps.
IMPORTANT NOTE: For high SPEED values (above 50-100) its strongly recommended to set “LPF” parameter greater
than 2-3, “Expo curve” parameter greater than 50, and “Dead-band” parameter greater than 3-5 degrees. Otherwise,
wrong system operation is possible, like vibrations and jerks under follow control, and overshoot of target.
•
LPF – adjust the low-pass filter applied to the speed control in the “Follow” mode. If this value is
set high, fast movements of the handle will be smoothed. But it requires careful operation and a
little training to prevent unwanted oscillations of the camera. Its recommended to not set it below
2.
•
Use Frame IMU, if possible – if 2nd IMU is connected, system can use it to detect the motor angles
instead of method based on electrical field estimation. IMU-based method is more reliable, because
it will not loose synchronization like in case of electrical field.
•
Apply offset correction when axis is not following – when any axis is not following, corresponding
motor should not produce control signal for it and for other axes. But when the axis enters follow
mode (for example, ROLL may be switched from "Lock" to "Follow" mode depending on PITCH
angle), or when frame is rotated such way that motor starts to stabilize another axis – motor should
produce zero control signal, even if its not in the "normal" position. Its recommended to have this
option enabled.
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7. Follow Mode Settings
Operation in the Follow Mode
At system startup in the follow mode, keep the frame horizontal and manually adjust the camera to the
horizontal position, and adjust it's heading. Camera easily "jumps" between the magnetic poles. Rotate the
camera by hands to desired horizontal position- it will stick to the nearest magnetic pole.
Gently rotate and tilt the frame. Turns within ±45º will control the speed of the camera from 0 to 100%.
Camera rotates in accordance with the SPEED settings until it's angles are not equal the frame's angles, or
until its given restrictions will be achieved.
If the camera moves unpredictably, perhaps its the wrong direction of rotation of the motors and you need
to change the Reverse flag in the 'Basic' tab .
To achieve smooth motion, increase the LPF parameter, increase the Expo curve, and decrease SPEED and
Acceleration limits. For more dynamic control, change these settings in the opposite direction.
In case of failure of stabilization due to external disturbances the camera can completely lose
synchronization with the frame. In this case it is necessary to return it to the proper position by hands.
You can switch between modes on-the-fly by activating different profiles, during this the camera will keep
its position between modes.
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8. Advanced Settings
8. Advanced Settings

AHRS - options influencing camera angle determination accuracy.
◦ Gyro trust – A higher value, gives more trust to the gyro data compared with the accelerometer
data when estimating angles. It can reduce errors caused by accelerations during movement,
but also decreases gyro drift compensation resulting in horizon drift over time. For smooth
flying it is recommended to set lower values (40-80) which will give a more stable horizon
longer. For aggressive flying it's better to set higher values (100-150).
◦ ACC low-pass filter, Hz - defines the cut-off frequency of 2nd order low-pass filter, applied to the
accelerometer data before it used as an attitude reference. It removes the disturbances caused
by the short movements with the lateral accelerations. Without such filter, these accelerations
affects the attitude vector, causing unwanted errors in the IMU angles, especially with the low
"Gyro trust" values. Setting the cut-off frequency a bit lower than the possible rate of
accelerations during normal use of a gimbal, can help to minimize their negative affection. The
trade-off is a delay, introduced to the accelerometer data, that increases the time of transient
processes in the sensor fusion algorithm.
Recommended value is 0.1 – 0.5 Hz. To disable the filter completely, set this parameter to 0.
◦ Accelerations compensation – enable use of a physical model of a multi-rotor to compensate
for accelerations during flight. This option works only when external flight controller (FC) is
connected and calibrated, so the controller knows the aircraft's tilting angles.

Serial port speed — changes baud rate used for serial communication. Decrease it when using
over-the-air serial adapters that can't use the maximum speed. The GUI can auto-detect the baud
rate configured in the board.

PWM Frequency — sets the PWM frequency used to drive the gimbal motors. Two basic modes are
available : Low Frequency (in audible range) and High Frequency (~22kHz outside audible range).
Recommended mode is High. There is also third option present: Ultra-high (~30kHz).

Motor outputs — you can randomly assign hardware motor outs for any stabilization axis, or disable
output that is not used, for 2-axis stabilizers. Options are:
◦ ROLL out, PITCH out, YAW out – motor ports on the main controller
◦ SBGC32_I2C_Drv#1..4 – external motor drivers, integrated directly into motors and controlled
by the I2C bus. More info: http://www.basecamelectronics.com/sbgc32_i2c_drv/

Sensor
◦ Gyro dead band - helps to cut off gyro noise around zero (that may be audible as 'white noise'
in heavy setups), and to make system more immune to self-excitation.
◦ Gyro high sensitivity - Increases gyro sensitivity twice. Use this option for big-sized DSLR
cameras, in case your PID settings are close to their upper limits, but stabilization is still not
good. Increasing gyro sensitivity equals to multiplying P and D values by 2.
◦ I2C high speed – use 2x faster communication over I2C bus. It may give positive effect by
reducing delay between gyro reading and correction, or in case if there are many devices are
connected to I2C bus. But it will increase a chance to get the I2C errors, so use this option with
care.
◦ Frame IMU – set the location of the frame IMU. See Second IMU sensor section of this manual.
◦ Frame upside-down auto detection – if enabled, the controller detects startup in the upsidedown mode: if you switch gimbal ON when frame is turned over by ROLL axes, but camera is
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8. Advanced Settings
not, - system enters upside-down mode automatically. If option is disabled, you have to enter
this mode manually by the menu command.
◦ Brief-case mode auto-detection – its useful in the “Follow” mode, when you turn frame by 90
degree over any axes, and do not want for camera to follow the frame. Converting to briefcase
position is very simple – just hold camera and rotate frame by 90 degree. Also it will be
automatically detected at startup, if you have the “Follow” mode enabled by default.
◦ Upside-down PITCH auto-rotate – when the frame is turned upside-down over PITCH motor,
camera will be rotated by 180 degrees to track new position of the frame. Be sure that PITCH
angle is not limited in the RC tab, to allow camera to make this movement.

External FC Gain – Gain value for matching the gimbal data from your flight controller (optional).
For better stabilization and utilization of some additional features, knowledge about the frame
inclination angles is required. In the single IMU configuration, there is no such information. But
most of FC's have servo outs for connecting gimbals, that may be used to obtain such information.
These outputs should be connected to SimpleBGC controller through EXT_ROLL and EXT_PITCH
inputs and the following steps to be performed:
◦ Activate gimbal outs in FC and set range limits for angles you generally fly (for example +-30
degrees of frame inclination should equal a full servo range of about 1000-2000).
◦ Deactivate all filters and smoothing for gimbal stabilization in the FC (if present).
◦ In the RC tab make sure that inputs EXT_ROLL and EXT_PITCH aren't used to control gimbal.
(i.e. are not chosen as a source for any other RC control task).
◦ In the Monitoring tab check availability of EXT_FC_ROLL, EXT_FC_PITCH signals and make sure
they are assigned to axes correctly. (Frame roll angle tilting should cause EXT_FC_ROLL change
in approximately the 900..2100 range. The same for pitch.
◦ Turn gimbal ON. It should be properly tuned and stabilization should work to this step.
◦ Push AUTO button in External FC Gain group and smoothly incline aircraft's frame to different
directions by all axes for 10-30 seconds. Controller will match signal from the aircraft and from
the IMU sensor and find a relation between them.
◦ Push AUTO button again to complete calibration. (Calibration will stop automatically after some
time too). New gains will be written into EEPROM and shown in the GUI.

Outer PI controller – this group of settings affects outer PI-controller, that control camera angle.
The bigger values, the faster camera returns to normal position after big declination. Normally,
there is no reason to change these values. Default value is 100 for all fields. These values are
linked to “I” value of the main PID controller, so if you increase I, Outer P, I will be increased too.
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9. Service Settings
9. Service Settings
Menu Button
If you've connected the menu button to BTN connector on the controller you can assign different actions to
it. Action is activated by pressing 'button' several times sequentially (1 to 5 clicks) and by pressing and
holding (long press).
Available actions:

Use profile 1..5 — loads selected profile.

Calibrate ACC, Calibrate ACC (temp. compensation) – the accelerometer calibration, works the same
way as the button selection in the GUI. Runs regular calibration or temperature calibration.

Calibrate Gyro, Calibrate Gyro (temp. compensation) – gyroscope calibration. Runs regular
calibration or temperature calibration.

Swap RC PITCH – ROLL — temporarily swap RC inputs from PITCH to ROLL. In most cases only one
PITCH channel is enough to control a camera in 2-axis systems. Before a flight you can assign
control from pitch channel to roll, and make a camera precisely leveled. Activating this function
again swaps channels back, and saves roll position in static memory.

Swap RC YAW – ROLL — like the previous point.

Set tilt angles by hand – motors will be turned off, after that you can take the camera in hands and
fix it in the new position for a few seconds. Controller will save and hold the new position. This
function may be useful to correct camera position before flight if there is no RC control connected.

Motors toggle, Motors ON, Motors OFF - commands to change the state of the motors.

Reset controller

Frame upside-down – configures system to work in upside-down position. New configuration is
stored to EEPROM and applied after restart. To switch back to the normal position, execute this
command again.

Look down - points camera 90 degree down (or maximum allowed limit under 90 as configured by
the MAX.ANGLE parameter in the RC tab).

Home position – returns camera to the initial position that is configured by the INIT.ANGLE
parameter in the RC tab. YAW axis returns to position where gimbal was started.

Level ROLL, PITCH to horizon – resets initial angle to zero and moves camera to “leveled” position.

Center YAW axis – if encoder on YAW is installed, controller moves camera to “normal” position by
YAW axis (where encoder shows zero angle).

Bind RC receiver – start bind procedure. This is applicable only for Spektrum satellite receiver, as
described in the “RC” section.

Menu button press – this is emulation of menu button single press. Example of use case: assign
toggle switch without fixation on your RC receiver to CMD channel; assign this action to High or
Low state of CMD channel, depending on toggle switch's active state. Now you can execute up to 5
actions by pressing switch remotely, as you do it be pressing the menu button.

Run script from slot 1..4 – execute your scenario from any slot. See User-written scripts section.

Untwist cables - if any motor made a revolution greater than 180 degrees, the system will rotate
the camera along this axis by 360 degrees in the opposite direction to minimize cable twisting.
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9. Service Settings
Camera after the maneuver will remain in the same position where it was. The following conditions
are required for proper operation:
◦ It must be known angle of the motor (via the encoder on the axis or second IMU-sensor)
◦ Twisting can be tracked only in the process. If the system has already started with a twisted
cable, it is impossible to figure out.
◦ The axis of the motor should be not inclined too much (no more than 60 degrees from its
normal position)
Additionally, there are special actions if you press 'menu' button more than 5 times:
•
•
•
10 times (starting from firmware ver. 2.55, 9 short clicks than 10th long press to protect from
accidental execution) – full erase of all settings. WARNING: Use this option for recovery only, if
board is not accessible from the GUI or no other ways to make it working.
8 times – all COM-ports function will be reset to their defaults: parsing of the SimpleBGC serial
protocol only.
12 times – Serial speed will be reset to default value 115200 and all COM-ports function will be
reset to their defaults. Use it if you changed the speed, but your wireless module, used for
connection to the board, does not support this speed and board becomes not accessible. (starting
from firmware version 2.50x)
Battery Monitoring
On all 32-bit boards there is a voltage sensor installed to monitor the main battery voltage. It is used to
apply voltage drop compensation (to ensure PID's remain stable during the full battery life-cycle), and to
provide power for low-voltage alarms and perform motor cut-off when the battery becomes discharged.
•
Calibrate - adjusts the rate of the internal multiplier to make measured voltage more precise. You
need a multimeter to measure the real voltage, then enter this value in the calibration dialog.
•
Low voltage - alarm - set the threshold at which to issue alarms.
•
Low voltage - stop motors - set the threshold at which to stop motors.
•
Compensate voltage drop - set this option to automatically increase the POWER parameter (which
controls the output power to the motors) which is applied when the battery looses voltage due to
the normal discharge process. This becomes unnecessary if the gimbal is fed from a voltage
regulated power source.
•
Set defaults for - select the battery type to fill the fields above with the default settings for
selected type.
Buzzer
On some boards there is an output to the buzzer (or a buzzer is installed on-board) that is triggered on
some events, like notification on errors or confirmation for user actions. Events are configured (turned ON
or OFF) in the GUI.
You can connect an active buzzer only (which has an internal sound generator), working from 5V and
current below 20mA (check this Digikey product search, for example)
If you have no buzzer connected there is an option to beep by motors. Note that motors can emit sound
only if they are powered and turned on.
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9. Service Settings
Status LED
There are 2 LEDs on the board. The Red LED lights when the power for MCU is present. The other LED
(which is either green or blue depending on the boards manufacture) gives more specific information about
the state of the system:

LED is off — pause before calibration, allows time to take hands off of or to level gimbal.

LED blinks slowly – calibration is in action. Keep the gimbal absolutely still throughout this
process.

LED blinks fast — system error, stabilization cannot be performed. To check error description,
connect to the GUI.

LED blinks fast for short time – confirmation for user action.

LED is on — normal operation mode.

LED is on, but blinks irregularly – there are I2C errors. Check in the GUI I2C errors counter.
Also, additional LEDs may be present to signal serial communication on RX and TX lines.
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10. System Monitoring
10. System Monitoring
In this tab you can see the raw sensor data stream, logical RC input levels and some debug information.

ACC_X,Y,Z – accelerometer data.

GYRO_X,Y,Z – gyroscope data. Helps to determine the quality of P and D settings- for example by
disturbing the gimbal by hand and observing the trace. If it looks like a sine wave the D setting is
too low and the gimbal tends toward low-frequency oscillations. If some noise is always present
even without any disturbance the D setting is too high and the gimbal tends toward high-frequency
self-excitation.

ERR_ROLL,ERR_PITCH,ERR_YAW – the stabilization error graph. This is the same as the peak value
indicators on the control panel and shows maximum deflection angle.
NOTE: Each graph can be turned on or off and scale can be adjusted for the Y axis. You can pause the data
transmission at any time.
You can receive extended debug information from the board by selecting the check-box “Receive extended
debug info”. Useful information you can get from the board:
•
RMS_ERR_R, RMS_ERR_P, RMS_ERR_Y – RMS amplitude of gyro sensor data. In case of oscillations,
it helps to clarify which axis is unstable. It may be not so clear from raw gyro data, because
oscillations may have high frequency, far above a frame rate that GUI can receive and display.
•
FREQ_R, FREQ_P, FREQ_Y – the main frequency of oscillation. If RMS_ERR is too small, this
parameter's usefulness is limited.
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11. Digital Filters
11. Digital Filters
This tab contains settings to configure digital filters that can help to improve the quality of PID controller
operation.
Notch filters
These filters can reject narrow bandwidth (resonance). They can help in cases when the system has a
pronounced mechanical resonance. Raising the extant feedback gain, oscillations will appear first on the
mechanical resonance frequencies and does not depend on variations of P,I,D settings. In this case using
one or more notch filters can help to increase feedback gain and get more accurate and stable work of the
PID regulator. But this filter will be useless if oscillations appear in the broad frequency range. In this case
it is better to use a low-pass filter. With the parameter Gain you can control the effect of the notch filter. Set
it equal to 100 to get maximum effect, set it <50 to compensate only light resonances. The image below
shows different values of the “gain” parameter in the Bode plot build for the PID controller with a single
notch filter at 60Hz:
Different values of Gain parameter for single notch filter
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11. Digital Filters
Example: gimbal behavior is stable, but when camera tilts downward 60 degrees a strong vibration occurs and
this effectively prevents an increase gain of PID (which might otherwise be desired to improve traction).
1. First detect which axis is causing vibration (most). To do this, in the GUI go to the tab
“Monitoring” and switch on the following graphics: RMS_ERR_R, RMS_ERR_P, RMS_ERR_Y.
Slowly tilt the camera downward until vibrations occur. The axis which shows the greatest
growth will show the primary axis responsible. In the example it is RMS_ERR_P, the Pitch
axis. A more precise way is to make a test of amplitude vs. frequency response in the
Analyze tab.
2. When in steady state vibration mode, look at frequency indication: check another variable
in the same tab: FREQ_P. It shows the main frequency of vibration (in our case it has the
value 100). Another way is to use a spectroscope (for example, an application for a
smartphone that takes an audio signal from mic), but this works only if the vibration is
well-audible.
3. On the tab “Filters” fill out the parameters for the first notch filter for Pitch axis:
Frequency: 100, Width: 10, Gain: 80 and check-box “Enabled” is switched on.
4. Write the parameters to board. Now try to re-establish the oscillation. For our example the
vibration has been significantly reduced and its frequency shifted to 105Hz. Change the
frequency of the filter to 105 Hz. Now the frequency is shifted to 95 Hz. Set back value of
the frequency to 100 and increase the bandwidth to 20. Now vibration on this resonance
frequency is completely gone. Note, you need to set the bandwidth as narrow as possible.
Too broad bandwidth can result in decreased PID efficiency.
5. Having closed one resonance, continue to increase gain of PID (responsible for gain are
the parameters P, D). Second resonance occurs on frequency 140 Hz, when we tilt the
camera upward. Fill in values for the second notch filter for PITCH axis to cancel this band
too, the same way as above.
In this example we have not needed to set filters for the other axes. But it can happen that resonance
occurs on more than one axis. Then you will need to set filters on both axes (possibly at the same
frequency).
Low-pass filter
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11. Digital Filters
It may be necessary to apply this filter (low pass filter) for large gimbals (heavy cameras with high moment
of inertia) or for gimbals with reduction gear. The working frequency range for them are lower than of the
lightweight gimbals. But factor D of PID also increases feedback at higher frequency. At high frequencies
the response of the mechanical system is typically not sufficiently precise because of many reasons: highfrequency resonances, propagation delay of mechanical impact, nonlinearity due to the backlash and
friction, and so on. Due to this the system tends to self-excitation when gain increases. A low-pass filter
reduces the gain at high frequency and increases stability of the system. But as drawback a low-pass filter
results in phase delay which grows negative near the crossover frequency and can adversely affect the PID
stability. This is the reason for the complexity of configuring this filter, and its usage is not always justified.
NOTE: Up to version 2.42 the parameter Gyro LPF was responsible for LPF and provided a first order filter. Now it is
not used and changed to a second order filter with more precise tuning of frequency and independent configuration
for each axis.
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12. Adjustable Variables
12. Adjustable Variables
SimpleBGC firmware supports not only the remote control of camera angles but also that of a large number
of system parameters, allowing their change in real time. Also it has expanded functions of various
commands executed remotely - similar to channel CMD but with a much more flexible configuration.
The tab with these settings is displayed after connecting to a 32-bit board with a firmware that supports
this feature.
There are two types of control: Trigger and Analog.
•
Trigger control is designed for connecting the buttons and switches in such a way that each state of
the button triggers a certain command pre-assigned to this particular state. The entire range of the
RC signal is divided into 5 sectors whereby the transition from one sector to another triggers the
action assigned. Up to 10 slots are available for matching the control channel set designed for 5
different functions.
•
Analog Control is designed for fine adjustment of selected parameters by rotating the
potentiometer on the remote control panel. It is also possible to switch between fixed values using
a multi-position toggle switch that almost all RC transmitters have. Up to 15 slots are available for
assigning the control channel to one parameter.
The source of a signal
For both types of Control, the signal source can be:
•
PWM inputs on the board designated as RC_ROLL, RC_PITCH, RC_YAW, FC_PITCH, FC_ROLL. They
take input from standard RC-receivers.
•
Analog inputs ADC1 - ADC3. They can be connected to analog potentiometers with resistance value
of 1-10 kOm (the end terminals are connected to GND and 3.3V and the central terminal is
connected to the ADC input in question).
•
Virtual channels from multi-channel RC. In the event of connection of RC-receivers with a large
number of channels over a single wire virtual channels of RC_VIRT_CH1 - RC_VIRT_CH32 receiver
can also be used. You can read more on this in the section "RC Inputs".
•
Virtual channels operated through the Serial API from another device. API_VIRT_CH1 -
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12. Adjustable Variables
API_VIRT_CH32.
TIP: This type of input allows independent developers to create an external control panel with any set of buttons,
switches and potentiometers, serviced by a simple microprocessor (for example based on the Arduino software),
which reads and transmits the state of control devices data over the wired or wireless serial-interface. Since the
tuning of control functions is performed through SimpleBGC_GUI, software for such control panel can be extremely
simple. Documentation of protocol «SimpleBGC Serial API specification» is available for download on our website –
http://www.basecamelectronics.com
Setting control of the Trigger type
•
Select a slot for tuning. Slots, where the signal source is already defined, are marked with '#'
symbol.
•
Select the signal source. One and the same source can be used for several slots simultaneously
(but please make sure that the commands executed for individual slots do not interfere with each
other).
•
Assign actions to each sector. Possible actions are described in the section "Menu Button". You can
leave any sector unused by specifying “no action”.
After activating parameters by pressing button "Write", you will see the current RC signal level on the
selected slot (for convenience, the whole range is divided into sectors), as well as the last activated action.
You can check in real time whether actions are performed correctly in the case when the level of the signal
has changed.
Setting control of the Analog type
•
Select a slot for tuning. Slots, where the signal source is already defined, are marked with '#'
symbol.
•
Select the signal source. One source can be selected to control the number of variables at the same
time, which can be convenient to change the value of a group of parameters by single control
function.
•
Select the variable that must be changed. Decoding of names of variables is presented in Table 1.
•
Specify the range of variation by means of the sliders Min. and Max. For example if the full
variation range is 0-255, and you need to change it to the range 100-150, you will need to set the
slider «Min.» at the mark close to 40%, and the slider «Max.» - at 60%, as shown in the picture:
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12. Adjustable Variables
In this case, the maximum control deviation corresponds to the parameter limit value of 153. Observing the
parameter current value in real time it is easy to estimate the required range by moving sliders.
There is a possibility to invert a control, so that when a signal goes up, a variable goes down. To achieve
this set Min. slider greater than Max slider.
You may notice that Min. and Max. sliders extend the range of a variable to ±10%. Its done for cases when
the RC signal is limited in range and does not cover the full RC range (correction of up to ±500 – and on the
screen the blue bar does not reach its limits).
After activating parameters by pressing button "Write", you will see the current RC signal level on the
selected slot, as well as the current value of controlled variable.
Table 1. Decoding of names of controlled variables
Parameter's name
Description
P_ROLL, P_PITCH, P_YAW
Parameter of 'P' PID-controller
I_ROLL, I_PITCH, I_YAW
Parameter of 'I' PID-controller multiplied by 100
D_ROLL, D_PITCH, D_YAW
Parameter of 'D' PID-controller
POWER_ROLL, POWER_PITCH,
POWER_YAW
Parameter 'POWER'
ACC_LIMITER
Acceleration limiter- unit of measurement: 4°/s (squared)
FOLLOW_SPEED_ROLL,
FOLLOW_SPEED_PITCH,
FOLLOW_SPEED_YAW
The speed of movement in the mode "Follow"
FOLLOW_LPF_ROLL,
FOLLOW_LPF_PITCH,
FOLLOW_LPF_YAW
Smoothing of operation in the mode "Follow"
RC_SPEED_ROLL,
RC_SPEED_PITCH,
RC_SPEED_YAW
Speed of movement when operating from the RC transmitter
RC_LPF_ROLL, RC_LPF_PITCH,
RC_LPF_YAW
Smoothing of operation from the RC transmitter
RC_TRIM_ROLL, RC_TRIM_PITCH,
RC_TRIM_YAW
Neutral point trimming for channels controlling the camera by ROLL,
PITCH, YAW in the speed mode
RC_DEADBAND
The dead-band of the RC signal for the camera control channels in
the speed mode
RC_EXPO_RATE
Degree of exponential curve depth for the RC signal
FOLLOW_MODE
Follow mode by the PITCH, ROLL angles: 0 - off, 1 - follow the flight
controller, 2 - follow the gimbal's frame
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12. Adjustable Variables
RC_FOLLOW_YAW
Follow mode by the YAW angles: 0 - off, 1, 2 - follow the gimbal's
frame
FOLLOW_DEADBAND
The dead-band for the deflection angle of the frame in the Follow
mode- unit of measurement: 0.1 degree
FOLLOW_EXPO_RATE
Degree of the exponential curve depth for the Follow mode
FOLLOW_ROLL_MIX_START
The starting point of the zone transition to the Follow mode,
degrees
FOLLOW_ROLL_MIX_RANGE
The length of the zone transition to the Follow mode, degrees
GYRO_TRUST
Trust to gyroscope compared to accelerometer
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13. Firmware update
13. Firmware update
To check if a firmware upgrade is available connect the board and press “CHECK” button. You will receive
information about all available versions of firmware and can choose version for upgrade. When selecting a
version in the drop-down list its full description is displayed in the text area below. To upload the selected
version to the board press the “UPGRADE” button. The uploading process will be started. Generally, it takes
about 10..30 seconds to finish. WARNING! Do not disconnect USB cable (or break wireless connection) while firmware
is uploading!
PLEASE NOTE:
•
For non-windows operating system, additional steps may be required. See notes at the end of this section.
•
For “Tiny” version of the board, you need to install the custom DFU device driver using Zadig utility. Driver
installed by default by Windows, does not suit! Detailed instructions on driver installation are provided at
the end of this section.
There is an option to configure the system to check for updates automatically. When a new version is
issued, you will be prompted to upgrade to it.
If automatic upgrade fails just after downloading firmware from our server (for example, there could be
problems upgrading when using a Bluetooth connection under Mac OS), you can try to upload firmware in
the manual mode. You can find the downloaded firmware in the 'SimpleBGC_GUI/firmware' folder and
upload this file to the board in manual mode.
Uploading firmware in the manual mode.
This option is intended for special cases when the board becomes bricked (GUI cannot connect to it) and
you need to upload special a “recovery” version of firmware, or when you experienced problems with
automatic upgrade. Use this mode carefully and only if you understand what you are doing!
1. Disconnect any power source and USB cable.
2. Close (set) FLASH jumper on board (attach jumper to the 2 pins marked as 'FLASH', thus shorting
them)
3. Connect board to PC by USB cable
4. Run GUI, select COM port (but don't connect!) and go to "Upgrade firmware", "Manual" tab but
DO NOT PRESS "CONNECT" IN THE GUI, IF JUMPER IS CLOSED! If pressed, you need to repeat all
steps from the beginning.
5. Choose firmware file (*.hex or *.bin format).
6. Select board version:
•
•
7.
v.3.x (32bit) through Virtual COM Port – for a regular 32-bit board
v.3.x (32bit) through USB in DFU mode – for a “Tiny” type 32-bit version. You need to update DFU
device driver before proceeding to the next step (see instructions below)
Press "FLASH" button and wait for process to finish.
8. Open (remove) FLASH jumper.
If board is alive (you can connect to the GUI), you can upload firmware in manual mode without setting
FLASH jumper:
1. Connect to board in the normal way.
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13. Firmware update
2. Choose firmware file.
3. Press "FLASH" button and wait for process to finish.
Upgrading under Mac OS and Linux
Starting from 2.42b7 its possible to upgrade firmware from the GUI under Mac OS and Linux (and virtually,
any other OS). The open-source tool stm32ld (https://github.com/jsnyder/stm32ld) is used to upload firmware
to the board.
NOTE: If the tool failed to run under your OS, you can compile it from source (located in the
'SimpleBGC_GUI/bin/stm32ld-src' folder). Place the result in the 'SimpleBGC_GUI/bin' folder, renaming it to
'stm32ld_mac' for Mac OS, 'stm32ld_linux' for Linux family, and 'stm32ld' for any other OS.
Installing DFU device driver
This driver is required only for “Tiny” version of the board when connected by USB. The open-source utility
dfu-util (http://dfu-util.gnumonks.org/) is used to write firmware to this board. This driver should be used
instead of default driver, installed by Windows.
Windows:
1.
2.
3.
4.
Download Zadig from the page http://zadig.akeo.ie/ (example)
Run Zadig. In the “Device" menu select "Load preset device.." (example)
Select file "SimpleBGC_GUI/conf/SimpleBGC 32bit board.cfg"
Install driver WinUSB (example)
To check that driver is installed properly:
1. Close (set) “FLASH” jumper on the board and connect it by USB
to PC (preserving this order exactly!)
2. Windows will find a new device "SimpleBGC 32bit board"
3. Open (remove) jumper, re-connect USB and run GUI to
upgrade firmware
Linux:
Most Linux distributions ship dfu-util in binary packages for those who do not want to compile dfu-util
from source. On Debian, Ubuntu, Fedora and Gentoo you can install it through the normal software package
tools. For other distributions (namely OpenSuSe, Mandriva, and CentOS) Holger Freyther was kind enough
to provide binary packages through the Open Build Service.
• Copy dfu-util to “SimpleBGC_GUI/bin/dfu-util-linux” to enable the GUI to find and execute it
MAC OS:
Mac OS X users can also get dfu-util from Homebrew with "brew install dfu-util" or from MacPorts.
• Install MacPorts from http://www.macports.org/install.php
• Find and install dfu-util from there
• Copy dfu-util to “SimpleBGC_GUI/bin/dfu-util-mac” to enable the GUI to find and execute it
FAQ and Troubleshooting
Q: Firmware uploading process was interrupted and board is not working now, not responding to GUI. Is it fatal?
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13. Firmware update
A: No, its not (permanently) fatal for your board (its impossible to damage the board in such way). You just
need to upload special "recovery" firmware. You can find it in the "firmware" folder, named
'simplebgc_recovery_32bit', or download it from our site. Refer to instructions on how to upload firmware in
the manual mode (above). Then, you can connect to the board and upgrade to any version, as usual.
Q: I know from somebody that there is new firmware version, but I don't see it when checking for updates. Why?
A: There may be beta versions that are available for beta-testers only, or maybe different versions for
different boards. You will receive only stable versions issued for your board by observing the specified
version for automatic update.
Q: Can I upgrade firmware from Mac or Linux?
A: Yes, starting from GUI 2.42b7. But check the note above.
Q: My board has no USB connector, but has bluetooth. Can I upgrade firmware?
A: Yes, you can upgrade via Bluetooth the same way as USB. If your board has an integrated Bluetooth
module it is already configured properly to work for upgrade. External Bluetooth modules need to be
configured to 115200 baud, even parity. If you have problems with re-connection to bluetooth under Mac
OS, you can try to upgrade in the manual mode using “FLASH” jumper, as described above.
Q: I am using an external bluetooth module and it works fine with the GUI. Can I upgrade firmware through it?
A: Yes, if you configure module to "Even" parity. To work with GUI, it may be either "Even" or "No" parity, but
to upgrade firmware it needs to be configured with "Even" parity only. Look for instruction for your module
how to configure it.
Q: Is it required to disconnect battery when upgrading firmware?
A: No, it does not matter if the board is powered from battery, or from USB only.
Q: After upgrade, my GUI can't connect to the board. What to do?
A: Its important that firmware and GUI both have matched versions. Changes in the firmware usually require
changes in the GUI, so old GUI will not work with the new firmware. You can download the matched GUI
from our website. A (hyper) link to a version matched GUI is generally provided in the description of the
firmware.
Q: I got an error during uploading: "CreateProcess error=14001"
A: Some required libraries are missing on your system. You need to install Microsoft Visual C++ 2008 x86
redistributable: http://www.microsoft.com/en-us/download/details.aspx?id=5582
Q: I got an error “Flash tool execution failed” and string “Cannot open the com port, the port may be used by
another application” in the details.
A: It may be because COM port number is greater than 99. Go to the Windows device configuration utility,
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13. Firmware update
open “Serial ports” settings, and rename port, giving it number below 100.
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14. System Analysis Tool
14. System Analysis Tool
This tool lets you grab information about system response and displays it in a form of “Bode plot” amplitude and phase response versus frequency. “System” for analysis purposes may be considered any
system that has input and output and unknown transfer function between them.
From Bode plot we can make an assumption about system stability, find problematic areas in frequency
domain, and with the help of advanced tools like Matlab find a way to increase the performance of the
controller.
This tool is quite complicated to use and is intended for use only by qualified personnel with an
engineering degree in systems analysis (control theory).
Collecting data
The main concept is to provide a “stimulus” signal to the input of the system, and then observe a signal on
the output. Input and output data is measured with a fixed sampling rate and stored in the CSV file. Then
signals are converted to the frequency domain, and a transfer function in the form of the cross-power
spectral density (CPSD) is computed. For all frequencies that are present in the input signal, we can build
amplitude and phase response plots. When displayed in logarithmic scales, its called a “Bode plot”.
Choosing stimulus signal
The most important things to say about a stimulus signal:
•
It should contain a wide spectrum of frequencies. White noise and sine sweep for example, meets
this condition.
•
System should operate inside its most “linear” range. If stimulus is too low – non-linear effects like
static friction and noise in the sensor used for measurement output will significantly impact test
result. If stimulus is too high, there is a chance to over-saturate the signal inside the system:
actuators may reach their limits, integrators may be clipped by wind-up thresholds, and so on.
Proper selection of the stimulus amplitude is very important to get test result close to reality.
Maybe several trials will be required to find clear-looking (and therefore useful) Bode plots.
•
Generally, the gain of a system decreases at the higher end of the frequency range due to
mechanical inertia. We can raise stimulus amplitude at high frequencies to compensate for this
drop in gain.
Open-loop vs closed-loop test
In most cases, we are interested in the “open-loop” system response. But if we have an integrator inside the
controller, we find that it has big gain for low frequencies that can lead to over-saturation of an output and
makes the system non-linear. For example, after integrating gyroscope data, we can get non-zero DC offset
of rotation speed. As a result, without negative feedback, camera will go to infinite rotation. Its not a
problem for analysis, because DC gain in the output data can be effectively removed. But in real word,
camera can't make infinite rotation because of physical limits.
The solution is to run system in the closed-loop mode and to mix the closed-loop feedback signal with the
stimulus signal. But near low frequencies, closed-loop system generally operates very well, that means
that the output of the system closely matches its input, and the stimulus signal is effectively removed. That
is the reason why the closed-loop mode is not perfect for analysis near low-frequency.
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14. System Analysis Tool
Starting test
In the “Analyze” tab press “Run test..” button and configure the test:
1. Select the axis to test
2. Select stimulus to feed to the input of a system
◦ White noise: this signal contains the full set of frequencies distributed uniformly.
◦ Sine sweep: signal with constant amplitude and frequency that goes from 1Hz to 500Hz.
◦ Sine sweep (exponential gain): the same as above but gain exponentially grows from value
set in “Gain” field at the lowest frequency to the maximum at the highest frequency. This
type of signal may help to increase the quality of analysis in the high-frequency area,
because system gain significantly drops there.
3. Select the gain of the test signal. Chose this value experimentally, to keep the system inside its
linear range during the whole test, and at the same time have non-zero output.
4. If “white noise” is selected as stimulus, select cut-off frequency. Frequencies above this will be
removed before passing to the test system. Note that the bode plot for the high-frequency area in
this case will be useless.
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14. System Analysis Tool
5. Select system to test:
◦ Controller + plant: input is passed to the PID controller, output is read from the gyro
sensor.
In
Out
Controller
~
Filters
Plant
PID
Motor
Mechanics
Sensor
◦ Controller only: input and output obtained from PID controller. In this test, motors are
disabled and test is not visible. Don't set a big gain (to prevent clipping inside controller).
In
Out
Controller
~
Filters
PID
◦ Plant only: input is passed to motor, output is read from gyroscope sensor. Again, be careful
with the gain parameter.
In
Out
Plant
~
Motor
Mechanics
Sensor
◦ Overall system response: input is passed as RC input and system tracks it as in normal
operation mode. Output should track input signal (gain is close to 0 dB, phase is close to 0
in well-tuned system).
In
~
Out
Controller
+
err
-
Filters
PID
Plant
Motor
Mechanics
Sensor
6. Place gimbal on a steady support, power motors ON and begin test. Its important to not disturb the
gimbal during the test, especially for open-loop modes. Full test will take about 40 seconds. This
time is enough to collect data for good averaging. But you can finish test at any time by pressing
“CANCEL”.
If something goes wrong during a test (for example, stimulus is too low and you see that the system's
response is too weak, or on the contrary stimulus is too big and the system goes outside limits (looses sync)
you can stop the test, correct start conditions and repeat the test again.
When the test is finished go to processing of the data collected. In the time-domain graphs, check that the
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14. System Analysis Tool
output of the system is not too low, otherwise test result will be overly noisy and unreliable.
Processing test results
When test is finished it is displayed in the GUI in a form of Bode plot:
But you can analyze grabbed data by more powerful tools like Matlab or similar programs. Therein are wide
sets of utilities from system identification to system tuning but high engineering skills are required to
make clear use of them.
Reading and understanding the test results
You need to understand the basics of system analysis before reading a Bode plot. There are many tutorials
and papers related to this area, for example:
http://support.motioneng.com/utilities/bode/bode_16.html
In few words, on the “Plant only” response graph you can see the response of motors and mechanics, and
check for potential mechanical resonances.
On the “Controller+Plant” response graph you can find the gain margin (0 minus amplitude at frequency,
where phase crosses -180 degree) and the phase margin (180 minus phase at frequency, where amplitude
crosses 0dB). The basic principle of stability: phase margin should be greater than 30 degrees. Gain margin
should be kept in the range -3..-6 dB. The bigger negative values means a more stable system but less
accurate tracking of errors. If the gain or phase margin is close to zero, the system is unstable and tends
toward self-excitation at those frequencies where zero margins are detected.
On the “Overall system” response graph you can find how effectively a system tracks its input signal on
different frequencies. You can estimate working frequencies where gain is close to 0dB and phase is close
to zero. Bumps on the gain plot can show potential resonances.
On the “Controller only” response graph you can see how the PID controller affects amplitude and phase of
the input signal and see the contribution of digital filters.
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15. User-written scripts
15. User-written scripts
With a special scripting language user can create a program to control a gimbal. The program is loaded into
the controller and is executed by a command from the RC or menu button. Language reference can be
downloaded by the link: http://www.basecamelectronics.com/files/v3/SimpleBGC_Scripting_Language_eng.pdf
There is a simple text editor in the Scripting tab with syntax checking. Its main functions are:
Saving and loading of files
Scripts are stored in text files. You can use any text editor to edit them.
Syntax checking
After loading a file, application checks the syntax. Errors found are highlighted in red and a short message
explaining the reason, is provided. Also, the syntax will be checked by clicking VALIDATE button and when
uploading the script to the controller.
Uploading scripts to the controller
There are 5 slots allocated that can hold up to 5 scenarios, the overall size (after compilation) of 27
kilobytes. Script size is displayed near the slot number. Empty slots are marked as <empty>. To delete a
script, delete all the text in text editor and write it into the slot you want to clear.
Restore script from the board
You can download the script from the board for editing. But at the same time, as a result of decompilation,
you will lose all comments and original formatting. Therefore it is recommended to store scripts in text
files.
Running scripts
RUN button will start the script located in the selected slot. If the text in the script editor window
corresponds to the contents of the slot, the current line of the program is highlighted in the process of
execution. This is useful for monitoring and debugging. You can stop the script at any time by pressing
STOP button
Other ways to run the script:
1. Assign command Run script from slot 1..5 to menu button in the tab Service;
2. Assign command Run script from slot 1..5 to the CMD channel of receiver in the tab RC;
3. Assign command Run script from slot 1..5 to any control channel in the group Trigger-type controls in
the tab Adjustable Variables;
4. Send the command CMD_RUN_SCRIPT through the Serial API.
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16. Encoders
16. Encoders
The encoder is a rotary position sensors, that provide very precise information about motor's shaft rotation.
This kind of sensor gives some advantages for stabilizer system
There are 2 versions of firmware exist: regular and extended. The difference is how they support encoders.
In the regular version, only one analog encoder is supported, installed on the motor that drives YAW axis.
Its recommended to use a special type of potentiometer, with infinite 360 degrees of rotation and low
friction. Also, magnetic type of encoder may be used, that has analog output.
Advantages of using encoder with the regular version of firmware:
• Precise work in the “Follow mode” even in the case of lost synchronization, that is important if
using a gimbal on the multirotors.
• Allow to install frame IMU in the “above YAW” position and correct cross-IMU gyro drift.
The extended version of the firmware requires to install precise absolute encoders on each motor and
calibrate them. It supports analog, I2C, SPI, PWM interfaces and various models of encoders. Advantages of
extended version:
• No need to install second IMU.
• Improved algorithm of motor control: no lost of synchronization, power consumption is lower,
torque is higher.
• Gives a reference for main IMU, if frame angle is known (may be important for application were
camera should be positioned in space by given coordinates).
Because of a high complexity of installing and tuning encoders, we do not consider them in this manual.
All information you can find on this page: www.basecamelectronics.com/encoders/
Below only regular version of firmware is described.
Connecting encoder
For potentiometer type of an encoder, the connection is simple: just connect 3.3V and GND terminals to its
side outputs, and connect the central output to any of A1..A3 inputs. For any other type, connect power
according to manufacturer's specifications, and its analog output to A1..A3. Note that supported voltage
range is 0..3.3V. Do not use the encoder that exceed this range on its output!
Calibrating encoder
•
Input – chose a port where encoder is connected
•
Gearing ratio – defines mapping between the voltage on the analog input and the angle. Value 1.0
corresponds to 0..3.3v → 0..360 degree of rotation. To estimate proper gearing ratio for your
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16. Encoders
encoder, use GUI as follows:
White arrow – shows the angle of motor relative to frame
Compass arrow – shows the (relative) angle of camera in space
1. If second (frame) IMU is connected – disable it temporarily (Advanced – Sensor – Frame
IMU – Disabled). Turn motors OFF.
2. Enter initial values: gearing ratio = 1.0, offset = 1 (or any non-zero value). Write parameters
to the board. If encoder is connected properly, the white arrow will start to display
rotations of the YAW motor.
3. Turn the frame that way that the white arrow matches the compass arrow. Fix the frame in
this position. Then rotate camera by YAW axis only, and check if the white arrow moves
together with the compass arrow. If it moves in opposite direction, mark “Inverse” checkbox. If the white arrow moves faster that the compass arrow, decrease gearing ration. In
opposite case, increase it.
•
Offset – set the zero angle. Move the frame in “normal” position* and press the “CALIBRATE” button.
A new value for this parameter will be set and displayed in the GUI.
* Normal position – position, where the frame points the same direction as the camera. If second IMU is installed, it's axes
exactly matches the main IMU's axes.
When the “Offset” parameter is set to non-zero value, encoder's data is used by firmware in calculations.
With the couple of second IMU (placed in the “Above YAW” position to get better results), it gives all
information of the frame position in space, that allows to increase the precision and reliability of
stabilization.
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17. Magnetometer sensor
17. Magnetometer sensor
A magnetometer helps avoid horizontal drift of the gyroscope, the same way as an accelerometer does with
vertical drift. But the use of a magnetometer is not always justified, since the process of measuring Earth's
magnetic field is much less accurate and reliable than measuring gravitational acceleration when using the
accelerometer. Furthermore, with installation of a magnetic sensor on the gimbal comes the need to
exclude the impact of the distortions caused by structural metal elements, permanent magnets and motor
windings, which may further complicate the process and reduce the sensor's effectiveness in application.
The use of the magnetometer is justified when shooting lengthy scenes in the Lock mode to avoid the
direction drift or in order to determine the exact orientation of the camera in the 3D space based on all
three coordinates, so as to allow for external GPS-aimed control.
Supported sensors and connectivity
The HMC5883L sensor is a currently supported affordable and popular model. A wide variety of modules
using this sensor are available for purchase. When selecting a sensor, bear in mind the following
requirements:
–
It must support +5V
–
It must be compatible with 3.3V logic (no LLC 5V for Arduino).
–
There should be no pull-up on the SDA and SCL lines; they should be connected to the embedded
+3.3V voltage regulator, not to the +5V!
The GY-273 module meets these requirements. As an example, the module's connection to the main IMU is
shown:
VCC
GND
SCL
SDA
SCL
+5V
SDA
GND
Magnetometer connection
Installation on the gimbal
The sensor is mounted on the same platform as the camera. The axes may be oriented randomly, but it is
important to ensure that the axes of the magnetometer are positioned parallel to the axes of the main IMU
sensor. If the gimbal or the camera contain metal parts with ferromagnetic properties (iron, steel, etc.), the
sensor must be mounted as far from them as possible. The sensor must also be mounted as far as possible
from the motors. For instance, the sensor can be offset on a 10-20 cm boom.
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17. Magnetometer sensor
BAD
GOOD
MOTOR
CAMERA
Magnetometer placement on the gimbal
Its possible to mount a magnetometer on the frame, where the 2nd (frame) IMU is mounted. In this case it
will correct the heading of the frame IMU, than the correction will be translated to the main IMU, as
described in the section The problem of mutual azimuth drifts of two IMU sensors.
Setting up the magnetometer in the GUI
Once the magnetometer is properly connected to the I2C bus, and 2.50b4 or greater firmware is loaded, a
new "Mag.Sensor" tab will appear in the GUI, enabling the magnetometer's calibration and setup.
First, specify its mount position (frame or camera).
Position of the axes
To ensure its proper operation, the position in which the sensor is mounted on the gimbal must be
specified. First, if the sensor's axes are not indicated on the module, determine their direction by using the
key spot on the sensor chip:
Z
CAMERA
VIEW
Y
X
In the Axis TOP parameter, specify which axis is aiming up. In the Axis RIGHT parameter, specify which axis
is aiming right, as viewed in the direction of the shooting (as shown in the example, Axis TOP = Z, RIGHT =
Y). Enter the settings in the controller and wait for it to reboot.
Magnetometer calibration
NOTE: For proper calibration, the sensor must be mounted on the gimbal. Make sure that the “Magnetometer Trust”
parameter is set to a value different from 0 (because the 0 setting disables the magnetometer).
Calibration may be initiated from the GUI, or by the menu command (you can assign it to the menu button
in the "Service" tab). It may be used to calibrate magnetometer in-the-field, without PC connection.
Press the Calibrate... button to launch Calibration Assistant. In the window that opens, press the RESET
button to reset the existing calibration. Then press the CALIBRATE button. During the calibration process,
controller gathers the measurements of the Earth's magnetic field in various directions. The progress
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17. Magnetometer sensor
indicator shows the percentage of collected data. Each new data point is marked by the single LED blink
and short sound (if motors are powered or buzzer is connected).
Then data points are fitted by an ellipsoid. To achieve a high quality of calibrations, it is important to
collect points that are well distributed over a sphere. The following algorithm is proposed:
• Point the sensor in the direction of the North or South (roughly)
• Make a full 360-degrees rotation over any of horizontal axes (PITCH, for example). You will collect
30-40% of points.
• Return the sensor to a normal position and turn it by 90 degrees (i.e. to the East or West)
• Make a full 360-degrees rotation over another axis (ROLL in our example). You will collect another
40% of points.
• Collect remaining data points by making random rotations.
When all data points are collected, a calculation will start automatically. It takes several seconds to finish.
Once the calibration is complete, its result is automatically recorded in the EEPROM and applied. If the
procedure is executed correctly, the sensor will display values in the range of ±1 on the diagram on random
movements.
NOTE: it's required to rotate the whole gimbal, not only the camera. The reason is that the position of the camera
relative to the motors (or ferromagnetic parts of a construction) may be changed and greatly distort the Earth's
magnetic field. See the "Installation on the gimbal" section to avoid such problems.
Monitoring the magnetometer's effectiveness
The calibration window displays the absolute difference between the North direction measured by the
magnetometer and the same angle measured by the gyroscope. As you know, in the short term, the
gyroscope (along with a properly calibrated accelerometer) provides a very accurate reading. If the error
remains in the green sector during all the camera pans and tilts, this means that
the magnetometer is working correctly and can be used to correct the drift of the gyroscope. If the error
increases significantly, the magnetometer should not be used. This may be due to a number of reasons:
1. The orientation of a magnetometer is set incorrectly. Check axis TOP, RIGHT settings;
2. Inaccurate calibration;
3. Improper installation, resulting in an impact of moving metal structures of the gimbal or motor
magnets;
Other settings
• Magnetometer trust: the greater the parameter, the stronger the correction of the current heading
direction (YAW angle) by the magnetometer. If the result of the effectiveness test is good, you can
use higher settings (50-100). Setting it at 0 disables the magnetometer. This value does not
interference with the gyroscope trust (that is applied only to the accelerometer).
• Magnetic declination – Magnetic declination refers to the angle between the geographic and
magnetic meridians on the Earth's surface where you are. The exact number can be found in
reference sources or on this map https://upload.wikimedia.org/wikipedia/commons/2/28/Mv-world.jpg This
parameter is only required for systems that rely on the precise location of the geographical North
(for example, for coordinating camera movements with a GPS when). In most cases, it can be set at
0.
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18. Bluetooth module configuration
18. Bluetooth module configuration
As it was mentioned in the "Computer Connection" section, for setting up a wireless connection via
Bluetooth module it is necessary to configure it properly. To help with this configuration there is a
configuration dialog box at GUI which can be run from the ”Board → Configure Bluetooth...” menu:
Specify a port of module's connection, module's type and its current settings in the "Connection" section.
Possible types of connection are:
UART1 is the main serial-port, present in every SimpleBGC controller, and it is marked as [5V, Gnd, Rx, Tx].
The module's connection is described in the Appendix B.
UART_RC is an additional serial-port combined with RC_ROLL (Rx) and RC_YAW (Tx) RC-inputs (see Appendix
B). To activate it choose a "RC_ROLL pin mode = SBGC Serial 2nd UART" mode in the RC tab and leave
RC_ROLL and RC_YAW physical inputs free. See Appendix B for reference.
UART2 is an additional port present only on some versions of the controller. It is absent on SimpleBGC32
“Regular” and SimpleBGC “Tiny”.
Supported modules and their special characteristics
To be able to configure the module you should put it into AT-commands mode and set correct port speed
and parity to which it is currently configured. Module's default settings are usually given at time of
purchase, but also you can find them in the User Manual for every module.
HM-10, HM-11, HM-12
Is in the AT-commands mode unless connected to a wireless device.
Default settings: Baud: 9600, Parity: none, Data bits: 8, Stop bits: 1, PIN:
000000, Role: Slave
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18. Bluetooth module configuration
HC-06, HC-04 and its clones
If module looks like in the picture, its obviously HC-06 type.
Is in the AT-commands mode unless connected to a wireless device.
Default settings: Baud: 9600, Parity: none, Data bits: 8, Stop bits: 1,
PIN: 1234, Role: Slave
HC-05, HC-03
Looks similar to HC-06, but allows more customization.
To change for the AT-commands mode it is necessary to short its Vcc and Key inputs while the power is off,
and then turn the power on. By doing so you turn it into AT-command mode and temporarily change the
port's speed to 38400 regardless of the speed value you've set before.
Default settings: Baud: 38400, Parity: none, Data bits: 8, Stop bits: 1, PIN: 1234, Role: Slave
RN-41, RN-42 (BlueSMiRF)
Automatically being switched into AT-commands mode within 60
seconds after the power is turned on unless connected to a wireless
device.
Default settings: Baud: 11520 Parity: none, Data bits: 8, Stop bits: 1,
PIN: 1234, Role: Slave
Module configuring
1. Connect module with one of UART-ports and choose its type and current settings. You can send a
test instruction to check the connection (as a rule it is “AT” command, and “D” for RN-42).
2. Reset the module to default settings by pressing the RESET TO DEFAULTS button
3. Set the appropriate port speed. For work via UART1 it should correspond the speed set for
controller in GUI ("Advanced" tab → "Serial Speed"). For other ports the speed should be 115200.
4. Set up the Parity setting. If you are not going to update the firmware via Bluetooth-module, choose
"None".
5. Set the name for the device that is visible for other devices during wireless connection setup.
6. Set the PIN which has to be entered for devices pairing.
7.
Press the WRITE button. You will see the configuration results in the log.
You can manually send AT-commands for module configuration by clicking the SEND button. Command
reference guide can be found in the datasheet for every module. Be careful as some commands can brick
the module
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19. Possible problems and solutions
19. Possible problems and solutions
Problem
Possible causes
Solutions
Motors don’t spin
-Power supply is not connected
-Supply polarity inverted
-POWER set to 0
-Check all connections
-Set POWER between 50..200
Camera is trying to align, but
falls back
-Camera is not balanced
-It's an error in motor windings,
or one phase is broken
- POWER is not high enough
-Balance camera
-Check motor winding
- Increase POWER parameter
During fast YAW rotating, camera
deflects by ROLL, and then
slowly gets to horizon.
-Bad accelerometer calibration
-Sensor is not in parallel with
motor axes
-Make advanced ACC calibration
by 6 positions
-Align sensor with motor axes
During fast motion with
acceleration, camera deflects,
and then slowly gets to horizon
-This is normal effect of
accelerations
-Try to increase Gyro Trust in
Advanced tab
YAW arrow slowly spins in the
GUI
-Slow drift is normal (less than 1
degree/minute). It’s because of
gyro drift over time.
-Note sensor Immobility during
gyro calibration
-Re-calibrate gyro
Camera slowly drifts by any or all
axes just after power on
- Bad gyro calibration
-Re-calibrate gyro
Clicks and
crunch are heard during work.
LED is synchronously blinking.
-I2C errors present. Errors are
possible if sensor wires are too
long, or motors outputs affect
sensor by capacitive linkage
(signal and power wires are run
close to one another and there is
capacitive linking).
-Shorten sensor wires;
-Lower pullup resistors values on
the sensor board;
-Install a spike LC-filter on motor
outs (make 2-3 turns of motor
cable through ferrite coil);
- Install spike LC-filter on sensor
wires (same as motor filter);
High-frequency oscillations.
-Feedback self-excitation as a
result of high D parameter
-Check the graphs to understand
on what axis the problem is and
lower D value.
Low-frequency oscillations.
-Feedback self-excitation as a
result of high D parameter or
low P parameter.
Lower P, increase D
GUI cannot connect to the board.
-Wrong COM-port selected
-GUI and firmware versions dont
match.
-Try different COM-ports
-Upload the latest firmware, and
download matching GUI version.
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20. Credits
20. Credits
Special thanks to William for contribution in writing this manual.
GUI translation: E-Copter / Fabien Deregel (French translation), Norbert Machinek (Deutsch translation),
Fpvmodel / Max (Chinese translation), Tomasz Ciemnoczułowski (Polish translation), Iacopo Boccalari
(Italian translation), Lubos Chatval (Czech translation), Henrick Almqvist (Swedish translation), Brandon
Kalinowski (English), Togawa Manabu/Pawana LLC. (Japanese).
© Basecamelectronics® 2013-2015
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SimpleBGC
SimpleBGC3.0
3.0(32bit)
(32bit)connection
connectiondiagram
diagram
IMU SENSOR
BATTERY
GND
CUT
+
5V
SDA
SCL
ADDR
BUZZER
(5..12V)
2nd FRAME IMU (optional)
IMU SENSOR
GND
BAT
USB
CAM STAB ROLL
I2C
+5V
GND
CAM STAB PITCH
GND
UART
SCL
SDA
VCC
GND
TXD
SPEKTRUM
+5V
+
ROLL
MOTOR
YAW
MOTOR
GND
SCL
+5V
Y
5V
SDA
RXI
X
BUZZER
RC_PITCH
FLIGHT
CONTROLLER
(OPTIONAL)
RC_ROLL
RC_YAW
FC_ROLL
FC_PITCH
GND
+3.3V
A1
A2
A3
BTN
AUX1..3
RECEIVER
ROLL
PITCH
+5V
YAW
GND
PITCH
MOTOR
MENU
BUTTON
CAM CONTROL ROLL / SumPPM / SBUS
CAM CONTROL PITCH
CAM CONTROL YAW
+3.3V
SIGNAL
GND
FERRITE RINGS (optional, if I2C errors)
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JOYSTICK 1..3
SimpleBGC
SimpleBGC3.0
3.0(32bit)
(32bit)bluetooth
bluetoothconnection
connection
Regular connection:
BAT
USB
RX
TXD
UART
SCL
SDA
VCC
GND
GND
TX
RXI
+5V
* To upgrade firmware via Bluetooth, only 'Even' parity will work.
** Starting from firmware ver 2.41, 'None' parity is supported, too.
Note, that by default, most modules configured with 'None' parity.
GND
+5V
(RC_ROLL pin mode = SBGC Serial 2nd UART)
Settings
Baud rate: 115200
Parity: Even* or None**
Data bits: 8
Stop bits: 1
BLUETOOTH
+
Optional connection:
Solder jumper to
provide +5V!
I2C
+5V
Gnd
Tx
Rx
GND
YAW
© 2013-2015 Basecamelectronics®
PITCH
ROLL
65
Bluetooth
SimpleBGC
SimpleBGC 32bit
32bit RC
RC signal
signal routing
routing diagram
diagram
Digital inputs
firmware
firmware ver.
ver. 2.43
2.43
Mapping
Serial decoders
MODE
RC_ROLL
SumPPM
VIRT_CH1
RC_PITCH
S-bus
...
RC_YAW
Spektrum
VIRT_CHx
Servo1
Servo2
Servo3
FC_ROLL
FC_PITCH
PWM out
Servo4
Mix
PWM decoders
Angle control
ROLL
Mix
Serial API
PITCH
YAW
Mapping
Command
API_VIRT_CH1
...
HIGH
CMD
API_VIRT_CH32
MID
LOW
Ext. FC signal
Analog inputs
FC_ROLL
ADC1
ADC2
FC_PITCH
ADC3
ADJ.VARS
© 2013-2015 Basecamelectronics®
66
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