Willow Garage PR2 Maintenance Manual
Willow Garage PR2 is a versatile mobile manipulator that combines perception, navigation, and manipulation in a single platform. It features a variety of sensors, including a laser rangefinder, stereo cameras, and an IMU, which allow it to perceive its surroundings and navigate autonomously. The PR2's two arms, each with 7 degrees of freedom, provide it with the ability to manipulate objects and interact with the environment.
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PR2 Maintenance
ROS + PR2 Training Workshop
PR2 Maintenance Overview
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PR2 overview
Review electrical and ESD safety
Review PR2 power system
PR2 accessory kit
PR2 tool kit
Hands on demos
See support.willowgarage.com
to order replacement parts
ROS + PR2 Training Workshop 2
PR2 Overview
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PR2 “anatomy”
Hands-on demos
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Filter maintenance
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Gripper tip replacement
Counter balance adjustment
Points of interest
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Power switch
A/C breaker
Run-Stop button
Plug for the ESD strap
ROS + PR2 Training Workshop 3
PR2 Front View
Top
Front
Shoulde rCovers
Laser
Sled
Head Tilt Stage Panels
Head Pan
Stage Panels
Center
Trim
Gripper
Fore Arm
Upper
Arm
Base Skirt
Front
Front
Bellows
Front
Bottom
Panel
ROS + PR2 Training Workshop 4
PR2 Side View
Grippe r
Laser
Sled
Top
Front
Panel
Fore Arm
Upper
Hokuyo
Front
Bottom
Panel
Base Skirt
Front
Head Tilt Stage
Panels
Head Pan
Stage Panels
Rear Top
Panel
Shoulde r Covers
Rear
Bellows
Rear
Bottom
Panel
Left
Body
Trim
Front
Bellow s
Base
Skirt
Rear
ROS + PR2 Training Workshop 5
PR2 Rear View
Head Tilt Stage
Panel
Rear
Top
Panel
Rear
Bellows
Rear
Bottom
Panel
Base
Skirt
Rear
Fan
Filter
Head Pan Stage
Panel
Run – Stop
Button
DC
Breaker
ROS + PR2 Training Workshop 6
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Electrical and ESD safety
When performing maintenance:
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Turn off power even when removing covers
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The only exceptions are when performing counter balance adjustments and replacing the fan filter
Disconnect AC power to the PR2
Always use an ESD strap
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ESD straps are provided in the accessory kit:
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Place strap around bare wrist
Plug jack into accessory panel
ROS + PR2 Training Workshop 7
PR2 Power System
PR2 internal power precautions and safety features:
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Battery power is “live” within the robot, even when the power is off
The power board controls all the power to the
PR2 systems and is accessible/controllable via the ROS pr2_power_node
There are as many as 7 levels of protection but you cannot assume they will prevent damage or injury
Always turn off the PR2 power when performing maintenance except when specifically required to complete a procedure such as the counter balance adjustment
ROS + PR2 Training Workshop 8
PR2 Power Requirements
Wall power:
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The PR2 can only be plugged into a dedicated
15A minimum circuit
Only use the supplied power cord
Only use the supplied self plug-in cord
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See support.willowgarage.com for ordering replacement cords
Battery runtime
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Approximately 2 hours stationary, less when moving
ROS + PR2 Training Workshop 9
PR2 Accessory Kit
15 FT power cord 68-06167 Gripper tips box:
Self plug-in cord 68-06153
Joystick 68-02985
Hard drive bay keys 68-03337
Wireless run-stop 68-01059
Sensor fingertips 68-03840
(x5) (use only with boots!)
Fingertip boots 68-03347
(x20)
USB joystick cable 68-03533
Small Checkerboard 68-03823
Fan filters 68-02802 (x5)
ESD strap 68-03024
Base station recovery DVD
User manual
PR2 Tool Kit (1)
Counter balance adjustment rod -
10mm hex 68-07034
1/4 sq. male to 1/4 hex male 68-07075
1/4 sq. drive to 1/4 hex female 68-07077
Counter balance adjustment tube
68-07147
3/8 sq. drive to 1/4 hex female 68-07078
10mm 3/8 drive socket 68-07079
Ratchet head bits:
1.5mm 68-07040
2.5mm 68-07042
13mm 1/4 drive socket 68-07085
13mm 3/8 drive socket 68-07086
Driver bits:
1.5mm 68-07062
2.0mm 68-07063
2.5mm 68-07064
2.5mm ball end 68-07059
3.0mm 68-07065
4.0mm 68-07066
5.0mm 68-07067
16mm 3/8 drive socket 68-07142
Needle nose pliers 68-07112
Diagonal Cutter 68-07146
Zip-ties 68-07150
PR2 Tool Kit (2)
7/32 1/4 drive socket 68-07090 1/4 drive flex joint, 68-07141
3/8 drive short extension, 68-07116 1/4 drive ratchet wrench, 68-07138
3/8 drive wobble extension, 68-07118 3/8 drive ratchet wrench, 68-07139
1/4 drive quick release extension,
68-07140
Needle Nose pliers, 68-07112
Mountz wrench and driver tools:
Fixed 0.34Nm wrench, with 1.5mm right angle Allen, 68-07025
Fixed 0.68Nm wrench, 68-07028
Fixed 2.0Nm wrench, 68-07029
1/4 hex ratchet head, 68-07033 (for use with 0.68 ans 2.0 Nm wrenches)
0.20 – 1.20 Nm torque tool, 68-07014
(small)
1 – 6 Nm Torque tool, 68-07015 (large)
Titan250I 5.6 – 28 Nm Torque wrench,
Using Torque Tools
Small and large driver
Special stack-ups
See support.willowgarage.com:
PR2 Toolkit: Setting Torque Driver
Blue Adjustment
Nob – Small
Torque Driver
Red Adjustment
Nob – Large
Torque Driver
Adjustment
Rotate
0.34 Nm 1.36 Nm (1.4)
Rotate to adjust torque
11.0 Nm
Using Loctite
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Use Loctite to retain fasteners and keep them from vibrating loose
There is no need to clean the old Loctite
The fresh Loctite will integrate with the old
Old Loctite.
Only a small
“patch” of Loctite is needed.
Today's Demos
Video of gripper tip replacement
Live demo of fan filter repair/replacement
Hands-on demo of counterbalance adjustment
See support.willowgarage.com
for all maintenance procedures
Gripper Tip R/R Video
Turn off power
Wear ESD strap
Always cover sensors with boots
Replace boots as soon as they show signs of damage
Willow Garage will not replace damaged sensor tips
Fig 6
See support.willowgarage.com for replacements
Fig 10
Fig 7
Fan Filter Demo
Clean regularly every 1-4 weeks
Clogged filter will cause fan speed to increase
(noisy robot)
Vacuuming filter is not recommended since this may tear the filter
Maintenance:
Remove the filter cover plate
Wash and dry filter
Having the fan on helps when placing the filter
Re-install the cover plate
Counter Balance Review
Overview: PR2 counter balance (CB) holds up the weight of the arms using a spring and pulley system
Goal: The CB should balance the arm so that almost no torque is required to maintain position of the arm
Performance: A well adjusted counter balance will maximize the performance of the PR2 arm controllers
CB Adjustment Overview
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With time, the springs of the CB system can start to sag or give. To maintain performance, you will have to adjust the mechanism.
Fig 1
Right
Secondary spring can be stiffened or loosened
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Clockwise (CW) turns increases force on arm
“Arm gimbal shaft” controls level arm length of CB spring force
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Counterclockwise (CCW) increases force on arm
Secondary Spring
Arm Gimbal Shaft
CB Adjustment Demo
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Demonstrate checking and adjusting the counterbalance on the PR2
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We will demonstrate up front
You will adjust your own counterbalance with help from Willow Garage engineers and technicians
Notes:
Safety first
You need two people to adjust the mechanism
Observe ESD protocol (wrist strap)
Watch for pinch points
CB Check Program
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We use a counterbalance adjustment/check program to adjust the counterbalance.
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The program moves the arm of the robot and measures the torque on each joint
It uses training data to recommend adjustments to for a minimum torque setting
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The program is an iterative solver, in some cases more than one iteration is required
You will run the check program and determine your required adjustment.
CB Check Program Install
Counterbalance adjustment program is unreleased .
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You will have to install it from wg-ros-pkg trunk and build it
Tutorial:
● ros.org/wiki/qualification/Tutorials
Follow tutorial instructions to install and build
Important: Do not start the CB adjustment program until instructed to do so
CB Adjustment Demo
Observe safety and ESD protocols.
Remove top covers, Doc6
Fig 1
Fig 1
Fig 2 Fig 3
Fig 4
CB Adjustment Demo
Observe safety and
ESD protocols.
Remove shoulder covers, Doc16
Fig 6
Fig 7
Fig 5
Fig 11
CB Adjustment Demo
Adjust counter balance, Doc5
Re-run the Check program and adjust the CB if needed,
Doc5
Fig 6
Re-install the covers, Doc6
Fig 5
Guide tube
CB Adjustment Procedure
Check CB with adjustment program
Clear out 2m space around your robot
Turn robot off ( sudo pr2-shutdown )
Remove covers
Ask your Willow Garage helper for questions
Adjust CB
Make adjustments check tool recommends
Turn robot on
Check CB with adjustment program
Turn robot off
Reinstall covers
Remember!
Safety First support.willowgarage.com
Always wear an ESD wrist strap
Don't be afraid to ask questions
Questions?????

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