Evaluation of ROS and Arduino CubeSat Rama kanth Ande

Evaluation of ROS and Arduino CubeSat Rama kanth Ande
Master Thesis
Electrical Engineering
August 2012
Evaluation of ROS and Arduino
Controllers for the OBDH Subsystem of a
CubeSat
Rama kanth Ande
Sharath Chandra Amarawadi
School of Computing
Blekinge Institute of Technology
371 79 Karlskrona
Sweden
This thesis is submitted to the School of Computing at Blekinge Institute of Technology in
partial fulfillment of the requirements for the degree of Master of Science in Electrical
Engineering. The thesis is equivalent to 30 weeks of full time studies.
Contact Information:
Authors:
Rama Kanth Ande
Addres: Karlskrona, Sweden.
E-mail: [email protected]
Sharath Chandra Amarawadi
Address: Karlskrona, Sweden.
E-mail: [email protected]
University advisor:
Prof. Craig Lindley
School of Computing
Blekinge Institute of Technology
University Examiner:
Dr. Patrik Arlos
School of Computing
Blekinge Institute of Technology
School of Computing
Blekinge Institute of Technology
371 79 Karlskrona
Sweden
Internet
Phone
Fax
: www.bth.se/com
: +46 455 38 50 00
: +46 455 38 50 57
ii
ABSTRACT
CubeSat projects in various universities around the world have become predominant in the
study and research for developing CubeSats. Such projects have broadened the scope for
understanding this new area of space research. Different CubeSats have been developed by
other universities and institutions for different applications. The process of design,
development and deployment of CubeSats involves several stages of theoretical and practical
work ranging from understanding the concepts associated with communication subsystems,
data handling subsystems to innovations in the field like implementing compatible operating
systems in the CubeSat processors and new designs of transceivers and other components.
One of the future trend setting research areas in CubeSat projects is the implementation of
ROS in CubeSat. Robot Operating System (ROS) is aiming to capture the future of many
embedded systems including Robotics. In this thesis, an attempt is made to understand the
challenges faced during implementing ROS in CubeSat to provide a foundation for the
OBDH subsystem and provide important guidelines for future developers relying on ROS
run CubeSats. Since using traditional transceivers and power supply would be expensive, we
have tried simulating Arduino to act as transceiver and power supply subsystems. Arduino is
an open-source physical computing platform based on a simple microcontroller board, and a
development environment for writing software for the board designed to make the process of
using electronics in major embedded projects more accessible and inexpensive. Another
important focus in this thesis has been to establish communication between CubeSat kit and
Arduino. The major motivating factor for this thesis was to experiment with and come up
with alternate ways which could prove as important measures in future to develop an
effective and useful CubeSat by cutting down on development costs. An extensive literature
review is carried out on the concepts of Arduino boards and ROS and its uses in Robotics
which served as a base to understand its use in CubeSat. Experiment is conducted to
communicate the CubeSat kit with Arduino. The results from the study of ROS and
experiments with Arduino have been highly useful in drafting major problems and
complications that developers would encounter while implementing ROS in CubeSat.
Comprehensive analysis to the results obtained serve as important suggestions and guidelines
for future researchers working in this field.
Keywords: Arduino Diecimila, Arduino UNO, CubeSat kit, Robot Operating System
i
ACKNOWLEDGEMENT
We would like to express our sincere gratitude to our supervisor Prof. Craig Lindley
for his constant support and motivation from the initial to the final stage that enabled
us to develop an understanding of the subject. We also thank him for sharing his
ideas in completing this work.
We would like to extend our gratitude to the examiner Dr. Patrik Arlos for
supporting us.
We also thank all the members of the Blekinge Institute of Technology for providing
us an opportunity to have quality education and research exposure in the field of
CubeSat.
We offer our regards and gratitude to the forum members of Arduino, Pumpkin Inc.
for their response and feedback, especially Mr. Andrew (President of Pumpkin Inc.)
who helped us in knowing many things.
Last but not least, we would like to thank our Parents, families and friends who
helped us with their valuable suggestions and encouraging us at every moment. Their
motivation helped us to overcome all the problems we encountered throughout the
study.
Regards,
Rama Kanth Ande
Sharath Chandra Amarawadi
ii
TABLE OF CONTENTS
ABSTRACT ...........................................................................................................................................I
ACKNOWLEDGEMENT .................................................................................................................. II
TABLE OF CONTENTS .................................................................................................................. III
1
INTRODUCTION ....................................................................................................................... 1
1.1
1.2
1.3
2
RESEARCH METHODOLOGY ............................................................................................... 3
2.1
2.2
3
CONSTRUCTIVE RESEARCH .................................................................................................... 3
QUALITATIVE RESEARCH ....................................................................................................... 3
BACKGROUND .......................................................................................................................... 5
3.1
3.2
3.3
3.4
3.5
3.6
4
PROBLEM STATEMENT ........................................................................................................... 1
RESEARCH QUESTIONS .......................................................................................................... 2
ORGANIZATION OF THESIS ..................................................................................................... 2
THE BEGINNING OF ARTIFICIAL SATELLITES ......................................................................... 5
SATELLITE CLASSIFICATION .................................................................................................. 5
THE CUBESAT STANDARD ..................................................................................................... 6
ONBOARD DATA HANDLING .................................................................................................. 7
ARDUINO ............................................................................................................................... 8
ROBOT OPERATING SYSTEM .................................................................................................. 8
THEORETICAL WORK ............................................................................................................ 9
4.1
LITERATURE REVIEW ............................................................................................................. 9
4.1.1 Real Time Operating System ........................................................................................... 9
4.1.2 Salvo RTOS .................................................................................................................... 10
4.1.3 Robot Operating System ................................................................................................ 11
5
REQUIREMENTS AND CONSTRAINTS ............................................................................. 15
5.1
HARDWARE COMPONENTS ................................................................................................... 15
5.1.1 CubeSat Kit .................................................................................................................... 15
5.1.2 Arduino UNO ................................................................................................................. 16
5.1.3 Arduino Diecimila.......................................................................................................... 18
5.1.4 Computer Specifications ................................................................................................ 20
5.2
SOFTWARE COMPONENTS .................................................................................................... 20
5.2.1 MPLAB ICD 3 ............................................................................................................... 20
5.2.2 Arduino .......................................................................................................................... 22
6
EXPERIMENTATION ............................................................................................................. 25
7
RESULTS AND ANALYSIS..................................................................................................... 28
8
CONCLUSION .......................................................................................................................... 35
9
FUTURE WORK ....................................................................................................................... 36
10
REFERENCES........................................................................................................................... 37
iii
LIST OF TABLES
Table 2.1 Classification of Satellites based on Mass ............................................................... 5
Table 2.2 Different ISIS CubeSat structures with maximum supported mass ........................ 6
Table 4.1 Arduino UNO Specifications ................................................................................. 17
Table 4.2 Arduino Diecimila Specifications .......................................................................... 18
iv
LIST OF FIGURES
Figure 3.1 CubeSat .................................................................................................................. 6
Figure 4.1 General Architecture of RTOS ............................................................................. 10
Figure 5.1 CubeSat Kit .......................................................................................................... 16
Figure 5.2 Arduino UNO ....................................................................................................... 17
Figure 5.3 Arduino Diecimila ................................................................................................ 19
Figure 5.4 MPLAB ICD 3 ...................................................................................................... 20
Figure 5.5 Selecting MPLAB ICD 3 as the Programmer tool ................................................ 22
Figure 5.6 Arduino and USB cable ........................................................................................ 23
Figure 5.7 Selecting the Arduino Board (Diecimila) .............................................................. 24
Figure 6.1 Experimental Setup ............................................................................................... 25
Figure 6.2 Communication between Arduino UNO and Diecimila ....................................... 26
Figure 6.3 Communication between CubeSat kit and Arduino .............................................. 26
v
LIST OF ABBREVATIONS
ANSIC
American National Standards Institute C Programming
AVR
Advanced Virtual RISC
DB
Development Board
DSC
Digital Signal Controller
GPOS
General Purpose Operating System
GS
Ground Station
HDLC
High-Level Data Link Control
IDE
Integrated Development Environment
I2C
Inter-Integrated Circuit
IPC
Inter-Process Communication
ISIS
Innovative Solutions In Space
LISP
List Processing Language
MB
Motherboard
MCU
Microcontroller
OBDH
Onboard Data Handling
OROCOS
Open Robot Control Software
OS
Operating System
PC
Personal Computer
PCB
Printed Circuit Board
RGMP
Real Time General Multi-Processor
ROS
Robot Operating System
RPC
Remote Procedure Call
RTOS
Real-Time Operating System
RX
Receive
SCL
Serial Clock
SDA
Serial data
SPI
Serial Peripheral Interface
TRMM
Tropical Rainfall Measuring Mission
TWI
Two Wire Interface
TX
Transmit
vi
1
INTRODUCTION
This thesis is a part of the CubeSat program at BTH. CubeSats are small artificial satellites
which are developed for improving accessibility to space research. These satellites are
standardized to a size of 10 cm cube and weight less than 1.33 kg. CubeSats weighing a few
kilo grams have increased low cost access to space experimentation in low earth orbit and
the main idea to design CubeSats as described in [1] is to use them as test beds for aerospace
engineering education and for research in space technology with reduced costs, development
time and minimized risks. CubeSats operating in the low earth orbit have allowed several
universities for developing and placing in orbit student-led, student-designed, student-built
and student-operated satellites by investigating all manner of scientifically exciting
phenomena, while giving a competitive edge to the graduates working on these projects [21].
[2] Describes the Onboard Data Handling (OBDH) system as the main subsystem of a
CubeSat that provides all the functionality and interfaces necessary to support CubeSat
operations. The primary goal of the communication subsystem is to send commands to and
from the CubeSat.
Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use
hardware and software [28]. There are many microcontroller platforms available for physical
computing but Arduino simplifies the process of working with microcontrollers over other
systems by offering some advantage for students, teachers and also is intended for artists,
designers, hobbyists, and anyone interested in creating interactive objects or
environments [28]. The microcontroller on the board is programmed using the Arduino programming language based on Wiring and the Arduino development environment based
on Processing [28] and the projects using Arduino can be stand-alone or they can
communicate with software running on a computer. The design of simulated subsystems like
power system and transceiver for CubeSat using low cost Arduino controllers is a
challenging task.
In the past few years, the Robot Operating System (ROS) has emerged as a standard and
open-source operating system for real-time robot control as described in [3]. ROS is an open
source platform that aims to capture the future of robotics and other systems. We would like
to introduce ROS in CubeSat as an established foundation for onboard software and test its
performance on an embedded system like CubeSat as compared to robots that are more
complicated in having multiprocessors and microcontrollers. The aim of the proposed project
is to assess the suitability of ROS on CubeSat.
1.1
Problem Statement
A CubeSat is defined as a ten centimeter by ten centimeter satellite, having a total weight no
more than 1 kilogram. The CubeSat standard will be a critical component in the research
field of CubeSat. The OBDH subsystem is the heart of the CubeSat which contains the
microcontroller installed with RTOS. There are many systems that use real time operating
systems designed uniquely for that particular system. The software designed for different
hardware‟s or missions is different and reusing the software for other missions may be
complicated and time consuming. Salvo RTOS manufactured by pumpkin is costly and is to
be purchased during the purchase of CubeSat kit that increases the overall cost. So, there is a
need to decrease the overall cost. In the past few years, the ROS has emerged as a standard
and open-source operating system for embedded robot control that has made a tremendous
change in the field of Robotics. ROS currently runs only on Unix-based platforms. A study is
made to check whether the ROS can give a foundation for the complex embedded system
like CubeSat. ROS is an alternative replacement for RTOS. There are many subsystems
present in CubeSat that makes CubeSat work like a satellite and these subsystems are sold
and available commercially which are expensive. This increases the overall cost of the
1
CubeSat project making it difficult for the small, medium organizations and Institutions to
work on it. So, reducing the overall cost is an important challenge that can be achieved by
simulating the subsystems using Arduino boards.
1.2
Research Questions
The main task of this thesis is to establish communication between the CubeSat kit, Arduino
and to study the requirements for installing an ROS on the OBDH subsystem of the CubeSat.
The research questions for this thesis are framed as follows.
1) Can the ROS provide a foundation for the Onboard Data Handling (OBDH)
subsystem of a CubeSat?
2) What are the advantages and disadvantages of ROS in robotics with respect to
CubeSat?
3) What are the problems encountered during the communication of the CubeSat kit
with Arduino?
1.3
Organization of Thesis
The outline of this thesis is provided before the specific requirements are discussed. A
thorough background search was conducted in finding the issues involved in installing the
ROS on OBDH and communication between the CubeSat and Arduino. In this chapter a
description of the CubSat concept and the problems involved in CubeSat project are
discussed. In chapter2 and chapter3, the brief history of CubeSat, OBDH, Arduino, Salvo
RTOS and ROS are discussed. Chapter4 includes the hardware and software requirements
for performing the experiment. Chapter5 describes the problems encountered during the
experimentation of the thesis work. The Chapter6 and 7 explains the detailed analysis of the
results and conclusion. Finally, in chapter8 the future work that can be done in the field of
CubeSat based on the contributions of this thesis is discussed. The references used in the
thesis are cited at the end of the document.
2
2
RESEARCH METHODOLOGY
In this chapter, the different methods used in this research work are outlined. The
methodology defines the process of research, working procedure followed by an explanation
of the experiment. In this chapter, the constructive and qualitative methods that are used in
our thesis work are presented. Most of the emphasis is on the qualitative research
methodology where the literature review is conducted in the first part and an experiment is
conducted for the later part. The references present in the references are used for finding
more and more references. A review of the previous works is done to acknowledge the
current knowledge to answer the research questions one and two in our research work where
an extensive literature is carried out on the concepts of ROS and OBDH.
2.1
Constructive Research
There are many real world problems, the solutions of which can be found using this
approach. In this method of research, the research need not be validated empirically as in
other research types like exploratory research. “Constructive research method implies
building of an artifact (practical, theoretical or both) that solves a domain specific problem in
order to create knowledge about how the problem can be solved (or understood, explained or
modeled) in principle that gives results which can have both practical and theoretical
relevance” [18].
The new contribution being developed like a new theory, algorithm, model, software or a
framework is often referred to as “construct”. It is important to observe that “constructive
research can also be viewed as a form of conducting case which is research parallel to the
theory illustration, theory testing and action research” [19]. In this approach, different
information sources such as training materials, literature reviews, processes, working
experience etc. are used for collecting the information which provides a theoretical body of
knowledge. When applied to a problem, it produces innovative constructs which may be
theory, algorithms, models or software making contributions to the theory of the discipline in
which it is applied.
In this approach, first the information related to Arduino and CubeSat are collected from
different sources. The construct in the thesis is a form of conducting a case to study the
simulation of power subsystem and transceiver subsystem using Arduino boards. This
construct or solution generates new knowledge for further extending the theoretical, practical
knowledge in the use of CubeSat kit and Arduino boards. The experimentation requires some
hardware and software components like CubeSat kit and Arduino boards for communication
purpose. The requirements about the usage of CubeSat kit and Arduino boards are extracted
from the manuals, data sheets and these provide a theoretical body of knowledge. The related
information is specified in chapter 5. The remaining work for answering the research
questions 2 and 3 is carried out using the qualitative approach described in the next section.
2.2
Qualitative Research
Qualitative research methods are commonly used within the field of information science.
Observation, case studies, surveys and documentary analysis are the main methods employed
in qualitative research. These methods are primarily not concerned on the explanation
produced but depend on increasing understanding of considerable area. Documents, which
are the useful source of data in qualitative research, are to be treated with care. In qualitative
research, data collection and analysis frequently takes place at the same time. The most
3
widely used are journals, official documents, personal documents, questionnaires, files and
statistics, textbooks.
The purpose of this literature review is to study about the OBDH subsystem of CubeSat and
also to find the overall requirements for installing the Robot Operating System on the OBDH
subsystem of a CubeSat. The basic requirements for installing an operating system and real
time operating system on any embedded platform are analyzed. The Salvo RTOS installed in
the CubeSat kit and its features are studied. A study on how to implement ROS on different
hardware platforms is performed. The different features of CubeSat and Robot are studied
and compared according to the work done in the experimentation, for answering the research
question 2. The different ways in which the microcontrollers can be communicated is studied
and the I2C is chosen for efficient communication. Later, an Experiment is conducted to
communicate the CubeSat kit with Arduino to answer the third question where the open
source Arduino boards are used for communicating with the CubeSat using an I2C. First, the
two Arduino boards are communicated using I2C and then the CubeSat kit is used for
communication with Arduino.
4
3
BACKGROUND
This chapter describes the necessary background required for the thesis which include the
classification of Satellites, the CubeSat standard, OBDH, Arduino and ROS.
3.1
The Beginning of Artificial Satellites
The man made satellite (artificial satellite) which is placed in the orbit is designed for a
specific purpose. The beginning of the satellites was started in the year October 1957, with a
mass of 184 pounds it was named “Sputnik 1” launched by the Soviet Union. It was using a
primary battery so it has re-entered the atmosphere in January, 1958 [5]. After that day,
many satellites have been sent which are used for communication, weather forecasting, etc.
The current trend in satellite development is again a preference for smaller satellites. With
cheaper costs, a wider array of small organizations, academic institutions and industries will
be able to utilize satellites to a large extent and more advantageous potential.
3.2
Satellite Classification
The satellite can be classified in many types i.e., they can be classified by their mission,
purpose, physical property etc. In our master thesis, we are mainly focused on the physical
properties such as mass, size, diameter etc. of the satellite. The table 3.1 taken from [15]
shows the classification of the satellite with respect to the mass. In [6], it is illustrated that
each satellite includes many subsystems and each subsystem has a role to play aboard the
satellite. In practice, in the field of the satellites design, each satellite subsystem, which
has dedicated hardware and software, is assigned to one team of experts because each
satellite subsystem belongs to one branch of science [15].
Table 3.1 Classification of Satellites based on Mass
Satellite Class
Large Satellite
Examples
Mass
>1000 kg
Minisatellite
Microsatellite
Nanosatellite
Picosatellite
TRMM, Hubble
Space
Telescope
IRIDIUM Satellites, GIOVE-A
Sputnik-1, Cerise
Vanguard-1, SNAP-1
CubeSat
Femtosatellite
Satellite-on-a-chip
1 – 100 g
100 – 1000 kg
10 – 100 kg
1 – 10 kg
0.1 – 1 kg
There are different ISIS CubeSat structures available which are developed as a generic,
modular satellite structure based upon the CubeSat standard. In [50], it is explained that the
building up of flight modules and stack of PCBs is first done in the secondary structure and
then is integrated with the load carrying frames at the end of the process, ensuring
accessibility of the flight avionics. The features taken from [50] are:





Highly modular design
Detachable side panels for maximum accessibility
Multiple PCB sizes supported
Dual Kill-switch mechanism
Scalable design to larger CubeSat form factors
5
Table 3.2 Different ISIS CubeSat structures with maximum supported mass
CubeSat
Structure
Part
production
tolerances
(mm)
Maximum
supported
mass (total in
gram)
Primary
Structure
Mass
(gram)
1-Unit
0.1
2000
100
Primary +
Secondary
Structure
Mass
(gram)
200
1.5-Unit
0.1
3000
150
300
2-Unit
0.1
4000
200
390
3-Unit
0.1
6000
300
580
4-Unit
0.1
8000
-
770
5-Unit
0.1
10000
-
960
6-Unit
0.1
12000
-
1160
3.3
The CubeSat Standard
The CubeSat standard started as a joint project between Cal Poly State University and
Stanford University in 1999 [16]. The CubeSat standard allows for many cost effective
satellite applications which are standardized to a size of 10 cm cube and weight less than
1.33 kg. The current trend in satellites to do more for less cost described in [22] has led to
the “Smaller, Cheaper, Faster, Better” space missions. Having small size and weight, as well
as a standard launching apparatus that can be attached to virtually any spacecraft, CubeSats
can be put into orbit frequently and cheaply. The figure 3.1 taken from [31] shows the
CubeSat.
Figure 3.1 CubeSat
6
The field of CubeSats is a very fast changing subject with improvements being made on a
regular basis as observed in the annual CubeSat conference organized by California
Polytechnic State University and Stanford University in US [54]. [15] Describes the main
idea of designing the CubeSats as using them as test beds for research in space technology
with reduced costs, development time and minimized risks.
The CubeSat program offers launch opportunities to universities that, otherwise, would be
unable to have access to space. The power system is used for the functioning of
microcontroller and communication by providing necessary power which also reduces the
weight and volume of the CubeSat. The simulation of the transceiver subsystem restricts
some requirements and specifications, but encourages the future designers in acquiring some
knowledge. The individual components of particular CubeSats, for the most part, have not
been interchangeable despite dozens of independent development efforts. The idea of
extending space plug-and-play avionics into CubeSats taken from [46] seems to be an
attractive proposition, since the interchangeability of components between disparate CubeSat
developments would likely result in significant economies in effort and reductions in the
time necessary to create CubeSats. In [46], it is illustrated that the CubeSats are constructed
painstakingly like their large counterparts (i.e., traditional spacecraft) and are among the
simplest class of space vehicles.
For the technology validation, [24] describes the CubeSats as scalable units which allow
smaller or larger vehicles to be developed using the specific resource requirements of the
technology, ensuring that the platform is simple and cost effective. The formulation of the
CubeSat concept has considerably lowered the entry barrier for countries or organizations
that wish to become space capable. However, despite the small size, building of a CubeSat is
a complex task that requires a set of very diverse skills and resources as explained in [20].
There are around 60 universities and institutions taking part in the CubeSat program helping
the students in developing their aptitudes and experience in the field of aerospace
engineering. In practice, in the field of the satellites design, each satellite subsystem, which
has dedicated hardware and software, is assigned to one team of experts because each
satellite subsystem belongs to one particular branch of science as illustrated in [1].
3.4
Onboard Data Handling
Each satellite includes many subsystems; each subsystem has a role to play aboard the
satellite [1]. The Onboard Data Handling (OBDH) system is the main subsystem of a
CubeSat which provides all the functionality and interfaces necessary to support the
operations of a CubeSat. The Onboard Data Handling Subsystem is the „brain‟ of the whole
CubeSat. For any OBDH, microcontrollers are considered to be the heart. For providing
various operation sequences, the OBDH subsystem of the CubeSat needs to be efficient,
small, lightweight and easy to integrate with other systems. The communication subsystem
of a CubeSat is of equal importance as that of the ground station which has to send various
information and data down to the ground station and vice versa. There are several constraints
to be considered in designing the CubeSat communication subsystem additional to that of the
ground station. The OBDH subsystem of the CubeSat performs several tasks like controlling
the different subsystems, communicating with the ground station, storing data and software
in particular allocated memories, managing and detecting the faults, checking data uplink
and downlink features by providing efficient programming as explained in [13]. All
spacecraft functionality including communication between the satellite and ground station,
navigation and telemetry, housekeeping, etc. is controlled by the OBDH using the flight
software.
7
3.5
Arduino
Arduino is an open-source physical computing platform based on a simple microcontroller
board, and a development environment for writing software for the board [28]. The widely
popular platform used in the applications in the microcontroller market is an Arduino having
an overall board size of 10cm x 10cm x 30mm. The Arduino programming language is an
implementation of wiring based on the processing multimedia programming environment.
There are different types of Arduino boards available and they can be chosen based on our
requirement. The Arduino‟s open-source IDE can be downloaded for free and can be used
for writing and uploading programs to Arduino I/O boards [28]. The Arduino projects are
stand-alone and the software incorporates various code examples from diverse open sources.
The advantages of Arduino over the other microcontroller systems taken from [28] are:
 Arduino boards are inexpensive.
 The Arduino integrated development environment (IDE) is available for Windows,
OS X, and Linux systems.
 The Arduino programming environment is clear, simple and easy-to-use for all the
users.
 The Arduino software is available as open source tools which can be extended by
other experienced programmers.
 The Arduino is based on Atmel's ATMEGA8 and ATMEGA16 microcontrollers.
The use of Arduino‟s in many engineering projects and research is considerably increased
due to its low cost and ease of accessibility.
3.6
Robot Operating System
Robot Operating System (ROS) is designed to promote code sharing and reusability by
creating and releasing a set of mature and stable software stacks for a faster progress in
robotics community. In 2007 the ROS concept is developed by Stanford Artificial
Intelligence as switchyard and was continued by Willow Garage to enable code reuse in
robotics research and development. ROS is not an operating system in the traditional sense
of process management and scheduling; rather, it provides a structured communication layer
above the host operating systems of a heterogeneous compute cluster [9]. [42] Describes the
main goal of the Robot Operating System (ROS) as enabling the researchers and developers
around the world to share the code and contribute to the growth of ROS. The Robot
Operating System (ROS) has risen as a standard and open-source operating system for realtime embedded and research projects in the past few years. The lack of architecture in ROS
libraries makes them much easier to integrate into other platforms and also makes it easy to
integrate code from other platforms (e.g., OpenRAVE, Player, OROCOS) into ROS [12].
From [4], ROS provides hardware abstraction, low-level device control, inter-process
communication API and package management.
I2C is a multi-master communication protocol that is used for data communication between
any two I2C devices, over two wires. The concept of master and slave devices is defined by
theI2C protocol and the I2C supports slave acknowledgment, providing that it is being
communicated with some device. Serial Peripheral Interface is a single-master
communication protocol where there is no acknowledgment about any data being
transferred.
8
4
THEORETICAL WORK
In this chapter, a detailed literature review is performed on RTOS, Salvo RTOS and ROS.
4.1
Literature Review
The literature review plays an important role in finding the existing research, what the
current state of art is and what other researchers says about any specific topic. Our main
focus was in finding research papers, articles, books and websites related to our research
area. To know the answers of our research questions, a deep literature review has been done
with the existing materials. For finding the information related to our research, different
search engines like Google, Engineering Village, IEEE Explore, BTH Library, Scopus,
Sciencedirect and Springerlink are used. Many websites related to the manufacturers of the
boards that are used in our thesis are visited often to get more and more information on the
specifications. A literature review process helps in understand the functionalities of the
system in detail. The datasheets of the microcontrollers used in the CubeSat kit and Arduino
boards are specifically studied to know the power supply requirements required for particular
boards, since they are very sensitive to the voltage supply.
4.1.1
Real Time Operating System
Operating System (OS) is a system program that provides an interface between hardware and
application programs. The main features of an operating system include multitasking,
synchronization, interrupt and event handling, input/output, inter-task communication, timers
and clocks and memory management. These features play an important role in managing the
hardware resources that meet the demands of application programs. “Real-Time Operating
System (RTOS) is a multitasking operating system intended for real-time applications.”
RTOS comprises of two components, namely, “Real-Time” and “Operating System” where
Real-Time indicates the response or reaction for an event on its existence as explained in
[27].
The advent of microprocessors has opened up several product opportunities that have
embedded themselves into all fields of our lives. As the complexities of the real-time
embedded applications increases, benefits of employing a real-time operating system
(RTOS) becomes ever more oblivious by making it the key to many embedded systems
today [27]. There are many RTOS‟s available today for the developers of embedded systems
like RTOS for robotics and RTOS for home appliances. RTOS is therefore an operating
system that supports real-time embedded systems by providing correct result, defining its
deterministic timing behavior and limited resource utilization nature. RTOS is effectively
designed and expanded easily meeting the performances required by the system.
RTOS are generally designed for hard real time RTOS, firm real time RTOS and soft real
time RTOS. They are also further classified according to the types of hardware devices (e.g.
8-bit, 16-bit, 32-bit MPU) supported. The main features of RTOS are multitasking, task
priority, reliable and control of memory management.
RTOS Architecture:
The RTOS architecture is based on the complexity of its deployment and good RTOS used
for different applications are scalable to meet different sets of requirements. The selection
criteria of RTOS can be broadly classified into two main areas; technical features of RTOS
like scalability, portability, run-time facilities, run-time performance and development tool
and commercial aspect of the implementation are costs, license and supplier stability [27].
Simple RTOS applications usually comprise only a kernel. For complex embedded systems,
9
an RTOS can be a combination of various modules, including the kernel, networking
protocol stacks, and other components as illustrated in figure 4.1 [27].
Figure 4.1 General Architecture of RTOS
4.1.2
Salvo RTOS
Salvo RTOS is designed to work in compact place where there are several limitations in
memory. It was specially aimed at less space environment like microcontrollers and
microprocessors. Salvo 2.0 was developed in ANSI C and assembly language for a task
specific extension for Pumpkin Cooperation with priority-based multitasking [33]. Salvo
provides basic multi-tasking kernel that supports sixteen separate task priority levels, the task
that are with same priority level are executed in round-robin format. There are many
functionalities that a salvo RTOS can provide in a real time operation that are described in
[25]. They are:
 Intertask communication
 Interrupt control
 Task scheduling
 Handles real-time delays
 Access to shared resources
C language is used to develop application and these applications are developed with specific
rules that are:
 Every task must contain at least one context switch
 Context switch may only occur in tasks [26]
Salvo does not use stack but still provides high performance real time operating platform
with efficient footprint, power consumption and memory utilization.
10
4.1.3
Robot Operating System
In the past few years, the Robot Operating System (ROS) has emerged as a standard and
open-source operating system for robot control as described in [3]. ROS is not an operating
system in the traditional sense of process management and scheduling; rather, it provides a
structured communication layer above the host operating systems of a heterogeneous
compute cluster [9]. The software mentioned in [15] does not use an operating system to
interact with each of the subsystems; instead C and assembly language are used for direct
system control. Most flight software is developed to work on a RTOS. Flight software
designed to use an RTOS is specific to the RTOS and specific hardware of a specific
spacecraft, so reusing the software for other missions may be complicated and time
consuming [8][10]. The complexity faced by reusing software with just one additional
module is described in [11]. The system described uses a Linux based software framework as
an operating system (OS) for flight software, providing the advantages of using an OS which
supports developing additional modules that can be easily implemented and integrated.
ROS provides operating system like service for robots. It is a meta-operating system which
loads on top of an operating system to provide a standardized set of software framework and
APIs. ROS is an open source platform that aims to capture the future of robotics. These
facilities cannot only help robots but also other embedded systems. So, supporting many
processors is a requirement. Robotics is a challenging systems integration problem and
requires a rich set of tools to successfully manage the complexity [35]. The robot operating
system software is licensed under BSD license and some of its included components are
licensed under various GNU license. ROS does basic things that allow more advanced
robotics quicker. So the main idea is not to spend lot of time in producing base platform
anymore because someone had spent years to design motor platform as finely as possible so
it‟s not necessary to do that anymore.
The main idea is to create sharing platform between universities, hobbyists and industries
that collaborate together to produce better robotics, higher end robotics and high end
thinking. Years passed but the collaboration doesn‟t exit and we keep repeating the cycle.
So, to stop that cycle, ROS was designed to move forward in robotics by having base
platforms. Robotics contains several processes running on more than one physical
component so for data exchange ROS provides an Inter-process communication (IPC). ROS
provides tools and libraries for building, writing, and running code across multiple
computers [38].
Design Goals of ROS:
There are many robotic frameworks such as player, yarp, Orocos, carmen, orca and
Microsoft Robotics studio has some sort of similarities in representing goal with ROS
framework but ROS mainly focus on code reusability. The primary design goal of ROS is to
meet a specific set of challenges encountered when developing large-scale service robots
[37]. ROS goals taken from [48] can be summarized as:
1. Distributed
2. Tools-based
3. Language Independent
4. Thin
5. Free and Open-Source
Distributed:
The distribution that occurs between processes is peer-to-peer communication. In general a
system built using ROS has many processes possibly on a number of different hosts,
connected at runtime in a peer-to peer topology that requires a lookup mechanism to allow
processes to locate each other at runtime [37].
11
Tools-based:
For reducing complexity of ROS, the developers have designed a microkernel with a large
number of small tools to build and run the various ROS components. These tools have its
own specific tasks like Visualizing the peer-to-peer connection, Navigating the source code
tree, Graphically plot message data, Set configuration parameters, Measure bandwidth
utilization and so on.
Language Independent:
Every coding individual has his own programing language preference and so for distributing
language preference the ROS is designed to be language-neutral. ROS currently supports
four very different languages: C++, Python, Octave, and LISP, with other language ports in
various states of completion [37]. The ROS specification is at the messaging layer making
Peer-to-peer connection negotiation and configuration occurs in XML-RPC, for which
reasonable implementations exist in major languages [37].
Thin:
The design objective of ROS is to make it as thin as possible so the code developed in ROS
can be compatible with other robot software frameworks. The compatibility and integration
of ROS has already achieved in OpenRAVe, Orocos and Player [38].
Free and Open-Source:
ROS is free and completely open-source. The full source code of ROS is publicly available.
Its prime goal is to develop an operating system for robotics that should freely available in
designing application for robots, which allows the development in commercial and noncommercial projects. The freely available ROS software is licensed under BSD license and
some of its included components are licensed under various GNU license.
The users of ROS are:
Industry
- Willow Garage, Bosch R&D, Vanadium Lab
Universities
- MIT, TUM, Stanford, Brown, Berkeley, USC, Rice, CMU, UPenn
Crazy hobbyists
ROS Platform:
Supported: currently ROS runs only in Unix-based platforms that to Ubuntu
- Ubuntu 11.10 to Ubuntu 9.04
Experimental:
- OS X (Homebrew), Fedora, Gentoo, OpenSUSE, Debian, Windows
Partial Functionality:
- FreeBSD, Android (roscore) [39]
The ROS concepts that are taken from [40] have three levels. They are:
1) The Computation Graph level
2) The Filesystem level
3) The Community level
ROS Computation Graph Level:
i.
Nodes: Nodes are a piece of hardware or processes that perform computation. In
general a robot system contain many nodes in it each node has its own specific task.
These nodes are developed from the client library.
12
ii.
iii.
iv.
v.
vi.
vii.
Messages: The communication between nodes is achieved by passing messages.
These messages are simple standard primitive types.
Topics: Topic is the name that is given for the message and then routed via transport
system. A node that is interested in a certain kind of data will subscribe to the appropriate topic. There may be multiple concurrent publishers and subscribers for a
single topic and a single node may publish and/or subscribe to multiple topics [40].
Master: Master is the central coordinator it provides node labeling and searches for
node participation in building a computation graph. Master plays a prime role in
processes communication.
Parameter Server: It‟s a part of Master which stores data in central location.
Services: services talks in two way transport for a faster communication. This is
described as a pair of message structure one for request and other for response from
the node. This is how services talk, for e.g., let us consider a sonic sensor talking to
motor in node communication, so the motor request the sensor where is the obstacle
and the sensor replies as response for it.
Actions: A complete set of communication between action client and action server
to do a task. This whole messaging technique is explained with an example.
Consider that a robot has to move five feet distance, so the goal is set with the
mobility processes these gives the status information of how much distance is
covered and how much is left out. If the task is down or not is shown in the result the
whole processes can be canceled any time. Feedback loop is to adjust the task if
some obstacle is occurred.
13
ROS Filesystem Level:
The development of ROS is governed by a package system, where one package is not more
privileged than another and the code is added by creating a new package [44]. The filesystem
allows developers to organize the code into packages and better handling dependencies [36].
i.
Packages: Packages can contain any-thing: libraries, nodes, message definitions,
tools, datasets or configuration. Each package should have enough functionality to
be useful but not so much as to make it heavyweight [35].
ii.
Stacks: A group of packages form a stack. Stacks provide the overall functionality
and explain the releases and versions of ROS software.
iii.
Manifests: The data related to license, package dependency, language specificity
and objectives are provided by manifests.
iv.
Stack Manifests: Stack manifests give information about collaborative stacks that
can utilize resources and information sharing to complete a task.
v.
Service types: Service types define the various types of services provided by ROS
like request, response, feedback and status. It defines the request and response data
structures for services in ROS.
ROS Community Level:
The ROS Community Level concepts are ROS resources that enable separate communities to
exchange software and knowledge. These resources mainly include the ROS wiki, ROS
answers, repositories, distributions, blog and mailing lists.
The main focus of ROS is on mobility, perception and manipulation of robots. For example,
ROS has resulted in the development of several high level algorithms which concentrate on
aspects like navigation, localization, planning and powerful data visualization.
14
5
REQUIREMENTS AND CONSTRAINTS
This chapter describes the hardware and software requirements for the CubeSat project.
5.1
Hardware Components
The hardware components used in the experiment are CubeSat kit and Arduino boards.
5.1.1
CubeSat Kit
The CubeSat kit's electronic hardware is designed around Pumpkin's space-proven satellite
architecture which supports different processors and the Motherboard (MB) implements
Pumpkin's CubeSat Kit architecture [31]. Pumpkin Inc. provides the highest-quality tools for
embedded system designers who are active in both software and hardware design. Salvo
provides RTOS for the CubeSat kit.
The Development Board (DB) has all the features of the motherboard including a variety of
features that make it suited for laboratory work. The following features taken from [31] are
included in our DB.






Two 104-pin CubeSat Kit Bus connectors
Inline jumpers for circuit isolation and current measurements
The power supply of +5V and +3V
A configurable RS-232 serial port with DB-9 connector
LED indicators for knowing the power status
A reset switch
Many existing CubeSat Kit users wish to implement SPI and I2C communications together
via the USART0 Peripheral Interface. We use the Pluggable Processor Module (PPM) D1
Hardware Revision: A board in our thesis. The main features of the PPM are:





CubeSat Kit Motherboard (MB)
16-bit Microchip PIC24FJ256GA110
Program memory of 256KB program memory
SRAM of 16KB
Up to 16MIPS - 32MHz
Integrated peripherals:
 UARTs - 4, SPIs - 3, I2Cs - 3
 16-channel 500ksps Analog to Digital Converter
 16-bit timers - 5
 9 compare / PWM outputs
 RTCC, WDT, ICD, JTAG
 Majority of peripheral pin selects are mapped to PPM connector
 8 MHz and 32.768 kHz clock crystals
 PCB - 4-layer gold-plated blue-soldermask
15
Figure 5.1 CubeSat Kit [31]
USB 2.0:
The CubeSat kit includes a USB 2.0-compliant USB port that can be used to communicate
between the CubeSat Kit and any PC running Windows, Mac OS X or Linux.
Multiple Serial Interfaces:
All CubeSat Kit PPMs provide at least two UARTs, one SPI channel and one I2C channel.
They are typically utilized as:
 UART0 is free for using in communication with a payload via RS-232.
 UART1 is for the transceiver interface.
 I2C0 is typically used to communicate with I2C devices.
 PPM D1 has four UARTs, three SPIs and three I2Cs, which leaves at least two
UARTs, two SPIs and two I2Cs that are completely open for user assignment [31].
RS-232 Port:
The Development Board provides an RS-232 driver for UART0.
Applications:
• CubeSat Nano satellite control, Command and Data Handling
• General-purpose low-power computing for CubeSat Kit architecture
• Remote sensing for harsh environments
5.1.2
Arduino UNO
The Arduino UNO is a microcontroller which consists of 14 digital I/O pins of which 6 pins
are PWM outputs, 6 analog inputs, a 16 MHz crystal oscillator, a USB connection, a power
jack, an ICSP header, and a reset button [29]. The Uno doesn‟t use the FTDI USB-to-serial
driver chip. Instead it features the Atmega16U2 programmed as a USB-to-serial converter.
"UNO" means one which is an Italian word and is named to mark the release of Arduino 1.0.
The Uno and version 1.0 will be the reference versions of Arduino, moving forward. The
Uno is the latest in a series of USB Arduino boards, and the reference model for the Arduino
platform [29]. The specifications of Arduino UNO are:
16
Table 5.1 Arduino UNO Specifications
Microcontroller
ATmega328
Operating Voltage
5V
Input Voltage (recommended)
7-12V
Input Voltage (limits)
6-20V
Digital I/O Pins
14
Analog Input Pins
6
Flash Memory
32 KB (ATmega328)
SRAM
2 KB (ATmega328)
EEPROM
1 KB (ATmega328)
Clock Speed
16 MHz
Figure 5.2 Arduino UNO [29]
P ow er :
The board consists of everything that is needed to support the microcontroller, which simply
connects to a computer with a flash or enable a power source with an AC to DC adapter to
get started [29]. The board is operated on an external supply of 6 to 20 volts, but the
recommended range is 7 to 12 volts.
The power pins of Arduino UNO taken from [29] are as follows:




VIN: The input voltage to the Arduino board when it's using an external power
source. The voltage is supplied through this pin, or, if supplying voltage via the
power jack, access it through this pin.
5V: This pin outputs a regulated 5V from the regulator on the board. The board can
be supplied with power from the USB connector (5V), or the VIN pin of the board
(7-12V).
3.3V: A 3.3V supply is generated by the on-board regulator and the maximum
current drawn is 50 mA.
GND: Ground pins.
M e m o r y:
The ATmega328 has 32 KB and has 2 KB of SRAM and 1 KB of EEPROM.
17
I n p u t a n d O u t p ut pi n s t a k e n f r om [ 2 9 ] ar e :
Each of the 14 digital pins on the Arduino Uno can be used as an input or output operating at
5V. In addition, some pins have specialized functions:
 Serial: 0 (RX) and 1 (TX) are used to receive (RX) and transmit (TX) TTL serial
data.
 External Interrupts: The pins 2 and 3 can be configured to trigger an interrupt on a
low value, a rising or falling edge, or a change in value.
 PWM: The pins 3, 5, 6, 9, 10, and 11 on the board provide 8-bit PWM output.
 SPI: The pins 10, 11, 12 and 13 support SPI communication using the SPI library.
 LED: A built-in LED is connected to digital pin 13. The LED is on when the pin is
HIGH in value and it‟s off when the pin is LOW.
The Arduino Uno has 6 analog inputs labeled A0 through A5. Some pins in addition
have specialized functionality:
 TWI: A4 or SDA pin and A5 or SCL pin which support TWI communication.
There are a couple of other pins on the board:
 AREF: This is the reference voltage for the analog inputs.
 Reset: To reset the microcontroller, we should bring this line LOW.
C o m m u ni c at i o n:
The Arduino Uno has a number of facilities for communicating with a computer, another
Arduino or other microcontrollers. The ATmega328 supports I2C (TWI) and SPI communic
ation providing UART TTL (5V) serial communication allowed by using SoftwareSerial
library, which is available on digital pins 0 (RX) and 1 (TX) [29].
5.1.3
Arduino Diecimila
The Arduino Diecimila is a microcontroller board based on the ATmega168 having 14
digital input/output pins, 6 analog inputs, a 16 MHz crystal oscillator, a USB connection, a
power jack, an ICSP header and a reset button. It contains everything that is needed to
support the microcontroller. It can be simply connected to a computer with a USB cable or
power it with a AC-to-DC adapter to get started.
"Diecimila" is an Italian word which means 10,000. It was named so as to mark the fact that
over 10,000 Arduino boards had been made. The Diecimila is the latest USB Arduino board
having the specifications as:
Table 5.2 Arduino Diecimila Specifications
Microcontroller
ATmega168
Operating Voltage
5V
Input Voltage (recommended)
7-12 V
Input Voltage (limits)
6-20 V
Digital I/O Pins
14
Analog Input Pins
6
Flash Memory
16 KB
18
SRAM
1 KB
EEPROM
512 bytes
Clock Speed
16 MHz
Figure 5.3 Arduino Diecimila [30]
P ow er :
The Arduino Diecimila can be powered via a USB connection or with an external power
supply. External power other than from USB can come either from an AC-to-DC adapter.
The board operates on an external supply voltage of 6 to 20V, but the recommended range is
between 7 and 12 volts.
The power pins of Arduino Diecimila taken from [30] are as follows:




VIN: It is the input voltage to the Arduino board when it's using an external power
source. The voltage to the Arduino can be supplied through this pin.
5V: This is regulated power supply used to power the microcontroller and other
components on the board which can come either from VIN via an on-board
regulator, or be supplied by USB or another regulated 5V supply.
3.3V: A 3.3V supply is generated by the on-board FTDI chip and the maximum
current drawn is 50 mA.
GND: Ground pins.
M e m o r y:
The ATmega168 has 16KB of flash memory for storing code and has 1 KB of SRAM and
512 bytes of EEPROM.
I n p u t a n d O u t p ut pi n s a r e :
Each of the 14 digital pins on the Diecimila can be used as an input or output which operates
at 5 volts.
19
Co mmu n i cati on :
The Arduino Diecimila has a number of facilities for communicating with a computer,
another Arduino, or other microcontrollers. The ATmega168 provides UART TTL (5V)
serial communication, which is available on digital pins 0 (RX) and 1 (TX).
The ATmega168 also supports I2C (TWI) and SPI communication and a Wire library is
present which simplifies the use of the I2C bus. I2C is a low-bandwidth, short distance
protocol for on board communications where all the devices are connected through two
wires: serial data (SDA) and serial clock (SCL) [30].
5.1.4
Computer Specifications
The minimum requirements for conducting the experiment are:






5.2
A computer is needed for the purpose of communication between CubeSat kit and
Arduino boards having the following.
1 GHz processor or faster processor
512 Mb RAM
40 GB Hard Disk Drive
Keyboard, Mouse
Connecting wires for communication
Software Components
The software components used in the experiment are MPLAB ICD 3, Arduino IDE,
Windows 7 operating system and Ubuntu 10.04 operating system.
5.2.1
MPLAB ICD 3
MPLAB ICD 3 In-Circuit Debugger System is Microchip's most cost effective high-speed
hardware debugger/programmer for Microchip Flash Digital Signal Controller (DSC) and
microcontroller (MCU) devices [32]. The debugger system will execute code like an actual
device because it uses a device with built-in emulation circuitry, instead of a special
debugger chip, for emulation [36].It debugs and programs PIC Flash microcontrollers and
dsPIC DSCs with the powerful, yet easy-to-use graphical user interface of MPLAB
Integrated Development Environment (IDE) and the Debugger probe is connected to the PC
using a high-speed USB 2.0 interface and is connected to the target [32]. MPLAB ICD 3 has
improved speed and supports all Emulation headers as compared with MPLAB ICD 2.
Figure 5.4 MPLAB ICD 3
20
Features:









Real-time Debugging: MPLAB ICD 3 In-Circuit debugger is designed for
supporting high-speed processors running at maximum speeds to debug applications
in real time.
Ruggedized Probe Interface: The probe drivers are added with some protection
circuitries in order to protect the kit from the target power waves.
Microchip Standard Connectivity: It employs a standard microchip debugging
connector (RJ-11).
Portable, USB-powered and RoHS-Compliant: Housed in a small (3.7" x.8") and
attractive enclosure, the MPLAB ICD 3 In-Circuit debugger is powered by the USB
port, so an external power adapter is not required [32].
High Speed Programming: Fast programming allows both quick firmware reload
for fast debugging and for in-circuit re-programming. Programming times are
improved up to 15x over MPLAB ICD 2 [32].
Low Voltage Emulation: It supports target supply voltages from 2.0 to 5.5 volts.
Test Interface Module: It is used to test I/O lines and confirm the unit is working
properly.
Ease of Maintenance and Feature Upgrade: Adding new device support and
advanced features is simple and can be field upgraded through a firmware.
Low Cost: It breaks the price barrier to interact with and debug applications at a
fraction of the cost of traditional emulator systems.
Installation procedures of MPLAB ICD 3 in-circuit debugger from [36] are:

Installing the Software: To install the software, we need to acquire the MPLAB
IDE installation executable (MPxxxxx.exe) from either the microchip web site or the
MPLAB IDE CD-ROM given during the purchase. We have used MPLAB IDE
v8.76.
 Installing the USB Device Drivers: The USB device drivers for the MPLAB ICD 3
in-circuit debugger are preinstalled by MPLAB IDE.
Connecting the Target:
This is done by pluging in the USB/power cable and the communication cable is
needed to be attached between debugger and target.
 Setting up the Target Board: The target must be set up for the type of target device
to be used.
 Setting up MPLAB IDE: Once the hardware is connected and powered, MPLAB
IDE may be set up for use with the MPLAB ICD 3 in-circuit debugger [36].
 Starting the MPLAB IDE Software: After installing the MPLAB IDE software,
invoke it by using any of these methods:
Select Start>Programs>Microchip>MPLAB IDE vx.xx>MPLAB IDE, where vx.xx
is the version number [36].
• Double click the MPLAB IDE desktop icon.
• Execute the file mplab.exe in the \core subdirectory of the MPLAB IDE
installation directory.
 Creating a Project: The easiest way to create a new project is to select Project>
Project Wizard, a new project and the language tools for building that project can be
created [36]. The wizard will guide the process of adding source files, libraries,
linker scripts, etc., to the various “nodes” on the project window. The basic steps in
[36] are provided here:
• Select the device (PIC24FJ256GA110)
• Select a language tool suite
• Name the project
• Add application files (e.g., program.c, support.s, counter.asm)
21




Viewing the Project: After creating a project, the project and its associated files are
visible in the Project window where we can add or remove extra files. Right click on
any line in the project window tree to pop up a menu with additional options for
adding and removing files.
Building the Project: Once the project is created, the application needs to be built,
which will create object (hex) code for the application that can be programmed into
the target by the MPLAB ICD 3 in-circuit debugger [36]. To set build options, select
Project>Build Options>Project.
Setting Configuration Bits: The device Configuration bits may be set in the
MPLAB IDE Configuration window choosing Select Configure>Configuration Bits.
Setting the Debugger as the Debugger or Programmer [36]: Select
Debugger>Select Tool>MPLAB ICD 3 to choose the MPLAB ICD 3 in-circuit
debugger as the debug tool, the Debugger menu and MPLAB IDE toolbar will
change to display debug options once the tool is selected. The Output window will
open and messages concerning MPLAB ICD 3 status and communications will be
displayed on the MPLAB ICD 3 tab. Select Programmer>Select
Programmer>MPLAB ICD 3 to choose the MPLAB ICD 3 in-circuit debugger as
the programmer tool, the Programmer menu and MPLAB IDE toolbar will change to
display programmer options once the tool is selected. The Output window will open
and messages concerning ICE status and communications will be displayed on the
MPLAB ICD 3 tab [36].
Figure 5.5 Selecting MPLAB ICD 3 as the Programmer tool
5.2.2
Arduino
The Arduino software includes a Wire library to simplify use of the I2C bus and for SPI
communication we use the SPI library. The Arduino software includes a serial monitor
which allows simple textual data to be sent to and from the Arduino board [34]. The RX and
TX LEDs on the board will flash when data is being transmitted via the USB-to-serial chip
and USB connection to the computer, via the FTDI chip and USB connection to the
computer [28]. We need to get an Arduino board and USB cable, download the Arduino
environment and use accordingly.
22
Figure 5.6 Arduino and USB cable [28]
Connect the board:
 The Arduino UNO automatically draws power from either the USB connection to
the computer or an external power supply [34].
 If you're using an Arduino Diecimila, ensure that the board is configured to draw
power from the USB connection.
 Connect the Arduino board to your computer using the USB cable. The green power
LED should go on.
Installing the Arduino drivers taken from [34]:
Installing drivers for the Arduino© UNO with Windows7 [34]:
 Plug in the board and wait for Windows to begin it's driver installation process
 Click on the Start Menu, and open up the Control Panel.
 In the control panel, we need to navigate to system and security. Next, click on
system. Once the system window is up, open the device manager.
 Look under Ports (COM & LPT). We should see an open port named "Arduino
UNO (COMxx)"
 Right click on the "Arduino UNO (COmxx)" port and choose the "Update Driver
Software" option.
 Next, choose the "Browse my computer for driver software" option.
 Finally, we navigate to and select the Uno's driver file, named "ArduinoUNO.inf",
located in the "Drivers" folder of the Arduino Software download.
 Windows will finish up the driver installation.
Launch the Arduino application:
 Double-click the Arduino application.
Open the example:
 After opening the application, open the required file.
Select your board:
In this step, the type of Arduino Board we are using is selected.
 Go to Tools>Board> Arduino Uno (for Arduino Uno).
 Go to Tools> Board: Arduino Diecimila (for Arduino Diecimila).
23
Figure 5.7 Selecting the Arduino Board (Diecimila)
Select your serial port:
 The serial device of the Arduino board is selected from the Tools, Serial Port menu.
 This will be COM3 or higher.
 The serial device is found by disconnecting Arduino board and by reopening the
menu; the entry that disappears should be the Arduino board.
 Reconnect the board and select that serial port.
Upload the program:
 Now, click the "Upload" button in the environment and wait a few seconds, we
notice that the RX and TX leds on the board flashing.
 If the upload is successful, the message "Done uploading" will appear in the status
bar and a few seconds after the upload finishes, we see the pin 13, LED on the board
starts blinking (in orange).
 When the light starts blinking, that means the Arduino is started.
24
6
EXPERIMENTATION
Our goal is to simulate transceiver and power supply subsystem‟s using Arduino UNO and
Arduino Diecimila for communication with CubeSat kit. In developing this, firstly we had
tried to get the communication between two Arduino‟s. Finally, an attempt has been made to
communicate between the CubeSat kit and Arduino for getting the simulated subsystems.
The components used in our experimental setup are CubeSat kit, Arduino UNO, Arduino
Diecimila, computer with Windows 7 operating system, connecting wires and Resistors (1.5
and 2.2 KΩ). The Arduino UNO is simulated as the transceiver and the Arduino Diecimila is
simulated as the power supply for the CubeSat. I2C (Inter-Integrated Circuit) is used for
communication between the two Arduino‟s and between CubeSat kit and Arduino‟s. I2C is
supported by many devices and is used for moving data simply and quickly from one device
to another.
Figure 6.1 Experimental Setup
I2C is a popular synchronous protocol that allows a master device to initiate communication
with a slave device simply and quickly. The connection details are shown below:
1. To run the CubeSat, a power supply of 5V is needed; this is given from the Arduino
UNO acting as the power supply subsystem for the CubeSat.
2. The Arduino Diecimila acts as a transceiver subsystem of the CubeSat that will
communicate with the Personal Computer (PC) in transmitting and receiving the
data.
3. The Arduino is connected to the PC (Personal Computer) using the USB cable and it
is also able to communicate with the PC using the Arduino IDE.
4. First, the two Arduino‟s are communicated. The first Arduino acts as the master and
the second acts as the slave device. In this communication, only one Arduino is
given the power supply and the second Arduino gets the power from the first
Arduino when connected.
5. The following communication between the Arduino‟s is successful:
 Arduino UNO as master and Arduino Diecimila as slave
25
 Arduino UNO as slave and Arduino Diecimila as master
6. A baud rate of 9600 is kept constant for communication between Arduino and
CubeSat, Arduino and Arduino.
Figure 6.2 Communication between Arduino UNO and Diecimila
7. The CubeSat kit is able to communicate with the PC using the MPLAB ICD 3.
8. The CubeSat kit is able to receive the power supply from the Arduino UNO but it is
not able to transmit and receive the data from Arduino Diecimila.
9. The different ways in which the communication between CubeSat kit and Arduino
are done is:
 Firstly, the CubeSat kit PIC is made as a master and the Arduino as a slave.
 Next we tried to communicate using Arduino as a slave and PIC as master.
 This process was carried out for different resistor values.
 We have verified these with the different codes provided by the Pumpkin,
Microchip, Arduino and had taken guidance from forum.
 A special care is taken for providing address for the devices as the PIC
generally takes the hexadecimal format and Arduino takes deciamal format.
 Also, the two clock frequencies 100 KHz and 400 KHz were used in the
attempt to establish communication between CubeSat kit and Arduino.
Figure 6.3 Communication between CubeSat kit and Arduino
26
This is a unique project in which the communication between CubeSat kit and Arduinos is
performed with the installation of ROS in OBDH. In all the cases, we have tried to
communicate using baud rate of 9600. The master and slave code for both the
communications are different. The master and slave device addresses plays an important role
in communication with each other. If the communication was successful, it would have been
very useful to many institutions, small and large organizations in field of CubeSat research,
as the cost decreases by a very huge amount.
27
7
RESULTS AND ANALYSIS
1) Can the ROS provide a foundation for the Onboard Data Handling (OBDH)
subsystem of a CubeSat?
Result:
From the extensive literature review that was performed to understand ROS and its
application in robotics, it can be clearly stated that, under the current circumstances where
ROS is still in the process of complete development and is evolving itself to adapt to
different technical needs and requirements, it cannot provide a total foundation for OBDH
subsystem in a CubeSat. The following points provide a comprehensive justification to our
answer.
1. Lack of real time framework:
i.
ROS is a meta-operating system which loads on top of an operating system to
provide a standardized set of software framework. This causes a huge hindrance in
choosing ROS for real time purposes because; first the system has to run Linux and
then ROS on it. Thus, ROS cannot handle real time issues.
ii.
Although ROS is not a real time framework, it is possible to integrate ROS with real
time but not under the present constrained scenario where CubeSat is provided with
a default hard real time running embedded system. The ROS software stack is built
on general purpose operating systems like Linux and Mac OS which makes it
difficult to run ROS with real-time support.
2. Insufficient memory size:
i.
CubeSat contains PIC24FJ256GB110 which is a 16 bit microcontroller with a
program memory of 256 kb and a RAM of 16 Kb. Under such minute memory
constraints, ROS cannot be run on a CubeSat.
ii.
The lowest hardware which supports ROS is gumstix which has a memory of 512
Mb.
3. Platform dependent:
i.
ROS is mainly supported on Linux platform and all its modules are developed in
Ubuntu.
ii.
The CubeSat developed by pumpkin is compatible with linux systems like Ubuntu
but the MPLAB IDE 3 debugger for PIC24 is not compatible with linux which
restricts the use of ROS in CubeSat.
Analysis:
ROS has been successfully implemented in Robotics. The inability of ROS to provide a real
time framework has been rectified with pr2_etherCAT which is a system used in Willow
Garage PR2 robot. This system transports ROS messages in and out of a real-time process.
ROS also has seamless integration with the Orocos Real-time Toolkit [38]. Real time tool
kits like Orocos when developed for CubeSats would eliminate the real time problems faced
by ROS. This would result in successfully using ROS for CubeSats to provide a foundation
for OBDH subsystems. The use of RGMP is also helpful for implementing ROS to achieve
real-time goals [43].
Platform dependency of ROS and memory restrictions can be overcome by using
uclinux based Linux 2.0 kernal for microcontrollers without memory management. ROS
provides AVR_bridge for supporting AVR microcontrollers. This results in implementing
ROS packages in Arduino by using rosserial_arduino package, without having to worry
about the memory constraints. If an API like an AVR_bridge for CubeSat PIC is developed,
then it would be possible to run and operate ROS packages in CubeSat.
28
2) What are the advantages and disadvantages of ROS in robotics with respect to
CubeSat?
Result:
ROS is primarily used in robotics and the option of using ROS in CubeSats should first be
carefully analyzed. For such an analysis, the use of ROS in robotics is studied and after a
broad review of ROS and its use in robotics has prompted the authors to list several of its
advantages and disadvantages. Features of ROS, their advantages and disadvantages in
robotics are taken as a base to understand the use of ROS in CubeSats. ROS so far has not
been implemented in CubeSats, and this study brings forward some of its benefits and
problems if implemented in CubeSats.
Advantages of ROS in Robots:
ROS
Advantages
Free & open source
Full source code of ROS is publicly available and there are many
API‟s and tools which are present in more than 2000 libraries. Anyone
can use these APIs by writing simple packages to their processes.
Robot independent
ROS is designed to be independent to the type of robot. It provides
libraries and tools to create robot applications regardless of the robot
being used. There are different categories of robots like Mobile
Manipulators, Mobile Robots, Autonomous cars, Humanoid, UAV‟s
etc. all of which can run on ROS.
Greater flexibility
ROS is a distributed framework of processes. Its main purpose is to
make a framework that is easy to integrate with other robot software
frameworks. This was achieved in OpenRAVE, Orocos and Player
[38].
Multi-lingual
ROS modules are designed in C++, Python and Lisp. Experimental
languages like Java and Lua are in development stage. Use of multiple
languages is an advantage in interacting with different modules of a
robot.
Easy testing
ROS has a built in test framework called „rostest‟ which makes it easy
to test and fix the problems [38].
Scaling
ROS is suitable for large development processes and runtime systems
[38].
29
Disadvantages of ROS in Robots:
ROS
Disadvantages
Platform specific
Presently ROS only runs in Unix-based platform. It was mainly
developed and tested on Ubuntu. There are many experimental
platforms like Windows, Fedora, OS X, Gentoo, Android etc., that
support some libraries of ROS.
Real-time support
ROS does not focus on real-time implementation but it had acquired
some real time features from Orocos real time tool kit.
Service oriented
ROS is a service oriented control system, it depends on peer to peer
topology and broad casting signals [45].
Time to learn
In learning ROS one should have sufficient knowledge in Linux, C++
or Python and robot framework. It takes time for effective
implementation of ROS.
Installation process
Installation process of ROS is a lengthy, complex and a time
consuming process.
Implementation of ROS in robots gives an idea on whether the different features would
prove advantageous or otherwise with respect to CubeSats.
CubeSat
ROS
Feature
Advantage
Device
independen
t
Easy
testing
---
Disadvantage
---
Easy testing mechanism
s are very effective in --detecting the problems.
Not Applicable
Device independence
of ROS doesn‟t have
an effect on CubeSats
since there are not
many types of CubeSat
s available as in the
case of Robots.
---
30
Flexibility
Free &
Open
Source
Installation
process
Multilingual
Platform
dependent
Real-time
support
Scalability
---
---
Free and open source
softwares are always a
huge advantage to work --with and use for testing
in
complicated
embedded systems like
CubeSat.
---
Future ROS versions
may prove to be
advantageous for use in
CubeSat
but
the
flexible
nature
of
present ROS may not
have much of an effect
on its use in CubeSat.
---
This is one of the biggest
disadvantages of ROS in
CubeSat since ROS is a --meta operating system
which must be installed on
top of Linux.
Since the primary focus
of using ROS in
CubeSat is on resource --management
and
scheduling, this feature
of ROS is an advantage.
---
---
The debugger used to write
the code for PIC24 in
CubeSat is used on
Windows
platform --whereas the current form
of ROS is designed to
work on Linux.
---
CubeSat requires complete
hard real- time support.
Current ROS version does
not provide real time --support and the ROS
integration with Orocos is
still in development stages.
CubeSats are miniaturezed satellites having spe
cific dimensions for
specific structures
making them scalable.
---
---
31
Service
Oriented
Time to
learn
---
Inter processor communica
tion is necessary in
CubeSat. All its communic
ations are from a centralize
d microcontroller.
---
Linux
and
other
programing languages are
important for CubeSat
developers but learning --new domains like robot
framework is a time
consuming process.
---
Analysis:
ROS so far has not been implemented in CubeSats and this study brings some of its merits
and demerits for implementation in CubeSats. The analysis is done by taking the advantages
and disadvantages of ROS in Robots that are considered for comparative study in CubeSats.
From the study, the CubeSat has advantages with ROS features like free and open source,
multi-lingual and scalability. The disadvantages of ROS in CubeSat such as platform
independent, real time support and some of the features are still in developing stages in ROS,
that might be overcome in future versions. The features like device independent and
flexibility are not appropriate for one particular CubeSat but these features may be a benefit
for large systems like NanoSats.
3) What are the problems encountered during the communication of the CubeSat kit with
Arduino?
Result:
The experimental setup involved designing simulated transceiver and power supply
subsystems with Arduino board. Several problems (mentioned below) were encountered
during the development and these problems coupled with the non-availability of protocol
analyzer resulted in suggesting that transceiver and power subsystems cannot be developed.
The problems faced during the development are classified as:
 Common problems
 Obscure problems
Common Problems:
These problems are basic technical/electrical problems which can be overcome by thorough
inspection and repeated testing. The following common problems were a challenge in the
process of development.
Problem
Voltage
Description
Correct supply of voltage is to be given for external devices. All the
external devices were powered correctly with their respective voltages.
32
Selecting resistor
To achieve I2C communication, pull up resistors for sending and
receiving the signal between devices are required. Two types of pull up
resistors - 1.5 KΩ and 2.2 KΩ were used.
I2C capabilities
Arduino and the PIC in Cubsat kit are supported by I2C. They have
their individual pins for connecting I2C. Arduino pins are 4 and 5,
CubeSat kit pc104 bus has I2C interface at pins 41 and 43.
Addressing
Some devices contain predefined address values that match with other
devices resulting in a conflict in I2C connection. In the Arduino IDE,
addressing is given in numerical formas Ex 42 or as the corresponding
decimal value. In PIC, the addressing has to be given in hexa decimal
format, so the slave address 42 is given as 0x2a and 10 is given as
0x3c.
Frequency
This is an important problem where special care is to be taken in
selecting the correct frequency between devices. This issue is resolved
by considering the two clock frequencies that are supported by these
devices FSCL = 100 kHz and FSCL = 400 kHz.
Baud rate
A baud rate is to be selected that is compatible with both the devices.
A baud of 9600 is selected.
I2C master support
PIC 24 of the CubeSat kit and Arduino are master supporting devices.
These are confirmed from the datasheet.
Connections
There is a possibility that the connection of SCL may be interchanged
with that of SDL. This interchange will not result in any output in
serial monitor of the Arduino IDE. These connections are properly
checked during the experiment.
Device testing
The Arduino boards are tested by using the sample code given in the
Arduino IDE. CubeSat kit is tested by the test code provided by Salvo.
Obscure problems:
These problems occur in I2C that stop the communication between devices.
Problem
Description
Negative
acknowledgment
Negative acknowledgment is a small error condition sent by the slave
may not be detected by the Master [41].
Voltage threshold
Devices using I2C may find it difficult in recognizing the high and low
values of SCL and SDL. These cannot be detected by an Oscilloscope
and more sophiscated equipment is needed in detecting such behaviors.
PIC24 has a voltage threshold at 5.2 volts and Arudino has a voltage
threshold at 5.3 volts.
33
Sensitive for cross The absence of Schmitt trigger and (or) spike filters in some devices
results in unnecessary disturbances in the signals caused by crosstalk
talk and noise
and noise. There is more noise when resistors are not present and the
signals are too small to respond [41].
Halt period
Sometimes, the signals are discontinued or become idle after some
time of interaction on the I2C bus. This is caused by an inappropriate
signaling of SDA or SCL by a sudden restart of the device [41].
Analysis:
These types of problems are hard to find using an oscilloscope. In [53] it is described that an
oscilloscope can help, but it is rather limited and does not help to analyze the protocol and it
is easy to miss the short transmissions altogether. In finding the obscure problems,
appropriate equipment like I2C protocol analyzer is needed. The protocol analyzer plays an
important role in knowing the detailed information about the signals in the communication
between the CubeSat kit and Arduino. Since I2C is a high-speed serial protocol, it is difficult
to debug with a simple multimeter. Pumpkin Inc, which is the developer of CubeSat kit we
are using, advises the use of I2C protocol analyzer as it is hard and very difficult to examine
the signals in communication between CubeSat kit and Arduino. The logic analyzers are
capable of examining I2C, SPI, UART, CAN and other protocols by capturing and
displaying signals from parallel busses. The advantages of using a protocol analyzer are:


The I2C protocol analyzer is mainly used for finding why the communication
between the devices is not working as expected by the user.
Protocol Analyzers understand the in-depth details of a given protocol, and can thus
report both correct and incorrect behaviors with supporting explanations about what
went wrong (or right) as explained in [52].
34
8
CONCLUSION
Literature review of several concepts associated with ROS and its applications in Robotics
have has been extensively performed. The experimentation involved attempts to establish
communication between Arduino and PIC24 of CubeSat. The following conclusions were
drawn based on the literature survey and experiments conducted.
1. Can the ROS provide a foundation for the Onboard Data Handling (OBDH)
subsystem of a CubeSat?
Under the current working conditions, where ROS is not fully developed, there are no
supportive features that can provide a foundation for its use in small and complicated
embedded systems like CubeSat. The present focus of ROS is completely inclined towards
Robot framework support. It can be concluded that, future versions of ROS can provide the
necessary functionalities like compatible APIs and proper real-time supporting features
which help further research to be carried out in ROS‟s use in CubeSat.
2. What are the advantages and disadvantages of ROS in robotics with respect to
CubeSat?
As mentioned in the previous answer, the present focus of ROS is on Robotics and since it
was not possible to install ROS in CubeSat, its features used in robotics are taken as a
standard to compare with CubeSat. This led to the conclusion that, ROS has no radical
impact on CubeSat as the advantages mentioned in results are not exclusive to ROS. Those
features along with several other important features are also available in many other RTOS
for use in CubeSat.
3. What are the problems encountered during the communication of the CubeSat kit
with Arduino?
The experimental analysis to answer this question has led to the conclusion that there are
several problems which can be encountered during the process of establishing
communication and these problems are categorized into common and obscure problems.
Importance must be given to overcome obscure problems as they are more difficult to
eliminate without a testing tool. The use of a testing tool, which in this case is the I2C
protocol analyzer, can clearly detect the correct and incorrect behavior for communication. It
also gives supporting reasons as to why communication could not be established.
35
9
FUTURE WORK
The use of ROS in CubeSats is one of the trend setting research areas in future. Few of the
future works related to this thesis are presented below:

The recent development of ROS which is integrated with real time tool kit - Orocos
provides a scope to research on the implementation of ROS in CubeSat by
developing appropriate and necessary APIs and libraries in ROS.

Implementing a radio protocol like AX.25 for a simulated transceiver can be a really
good area of future research in this field.

Arduino has useful ROS libraries and tools, which would be helpful in using it to
design other simulated subsystems for CubeSat.
36
10
REFERENCES
[1] A. Addaim, A. Kherras, E.B. Zantou, “Design of Low-cost Telecommunications
CubeSat-class Spacecraft,” Aerospace Technologies Advancements, Thawar T. Arif (Ed.),
ISBN: 978-953-7619-96-1.
[2] J. P. Diestro, F. C. Martínez, B. G. Gómez and A. G. García, “Spain´s minisat01 Onboard data handling subsystem and On-board Software” Available from
http://www2.dem.inpe.br/ijar/dasia96.pdf [Accessed: 17-May-2012].
[3] S. Cousins, "Exponential Growth of ROS," IEEE Robotics & Automation
Magazine, vol.18, no.1, pp.19-20, March 2011.
[4] K. Conley, ROS.org. (2012, May) ROS.org. [Online].
http://www.ros.org/wiki/ROS/Introduction. [Accessed: 21-May-2012]
[5] J. A. Larsen and J. D. Nielsen, “Development of CubeSats in an educational context,” in
Recent Advances in Space Technologies (RAST), 2011, 5th International Conference, 2011,
pp. 777-782.
[6] H. L. Denise “Communications Infrastructure for the MOST Microsatellite Project,”
Master's thesis, National Library of Canada., 2000.
[7] D. Speer, G. Jackson and D. Raphael, "Flight computer design for the Space Technology
5 (ST-5) mission," Aerospace Conference Proceedings, 2002. IEEE, vol. 1, pp. 1-269.
[8] D. Mathur, B. W. Edwards, J. Goldstein, H. Nguyen, J. Pine, B. A. Plante, J. C. Thacker,
C. Hoover, "An Approach for Designing Reusable, Embedded Software Components for
Spacecraft Flight Instruments," Real-Time and Embedded Technology and Applications
Symposium, IEEE, 2005, pp. 106-115.
[9] M. Quigley, B. Gerkey, K. Conley, J. Faust, T. Foote, J. Leibs, E. Berger, R. Wheeler,
and A. Y. Ng, "ROS: an open-source Robot Operating System," in Proc. Open-Source
Software workshop of the International Conference on Robotics and Automation (ICRA),
2009. Available from: http://ai.Stanford.edu/~mquigley/papers/icra2009-ros.pdf.
[10] “Innovative high performance nanosatellite science and technology demonstration
mission,” Jayaram. S, 2009 Acta Astronautica 65 (11-12), pp. 1804-1812
[11] M. Schmidt, K. Schilling, “An extensible on-board data handling software platform for
pico satellites,” Acta Astronautica, Volume 63, Issues 11-12, December 2008, Pages 12991304, ISSN 0094-5765, DOI: 10.1016/j.actaastro.2008.05.017.
[12] Cousins. S, Gerkey. B, Conley. K, Garage. W, "Sharing Software with ROS [ROS
Topics]," Robotics & Automation Magazine, IEEE, vol. 17, no. 2, June 2010, pp. 12-14.
[13] A. Addaim, A. Kherras, E.B. Zantou, “DSP implementation of integrated store-andforward APRS payload and OBDH subsystems for low-cost small satellite,” Aerospace
Science and Technology, Volume 12, Issue 4, June 2008, Pages 308-317, ISSN 1270-9638,
DOI: 10.1016/j.ast.2007.08.002.
[14] A. Addaim, A. Kherras, E.B. Zantou, "Design of Store and Forward Data Collection
Low-cost Nanosatellite," Aerospace Conference, 2007 IEEE, pp.1-10, 3-10 March 2007,
DIO: 10.1109/AERO.2007.353099.
37
[15] J. M. Nelson, “Persistent Military Satellite Communications Coverage Using A CubeSat
Constellation In Low Earth Orbit,” University of Central Florida Orlando, Florida, 2010.
[16] B. K. Kfzeo and J. A. Kigiv, “A Survey of CubeSat Communication Systems,” Micro,
April 2008, pp. 1–36.
[17] R. B. Johnson and A. J. Onwuegbuzie, “Mixed methods research: A research paradigm
whose time has come,” Educational researcher, vol. 33, no. 7, pp. 14–26, 2004.
[18] G. D. Crnkovic, “Constructive Research and Info computational Knowledge Generation
,” in Model-Based Reasoning in Science and Technology, vol. 314, L. Magnani, W.
Carnielli, and C. Pizzi, Eds. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010, pp. 359380.
[19] K. Lukka, “The constructive research approach,” Case study research in logistics.
Publications of the Turku School of Economics and Business Administration, Series B, vol.
1, no. 2003, pp. 83-101, 2003.
[20] L. Alminde and K. K. Laursen, “A strategic approach to developing space capabilities
using CubeSat technology,” Recent Advances in Space Technologies, 2009, RAST ’09. 4th
International Conference on, 2009, pp. 43–47.
[21] “NASA - Interplanetary CubeSats: Opening the Solar System to a Broad Community at
Lower Cost.” [Online]. Available: http://www.nasa.gov/offices/oct/early_stage_innovation/n
iac/staehle_interplanetary_cubesats.html#backtoTop. [Accessed: 21-May-2012]
[22] H. Heidt, J. Puig-Suari, A. S. Moore, S. Nakasuka, and R. J. Twiggs, “CubeSat: A new
generation of picosatellite for education and industry low-cost space experimentation,” in
Proceedings of the 14th Annual AIAA/USU Conference on Small Satellites, 2000, pp. 1–19.
[23] J. Sarik, I. Kymissis, “Lab kits using the Arduino prototyping platform,” in Frontiers in
Education Conference (FIE), IEEE, 27-30, Oct. 2010, pp. 1-5.
[24] S. Greenland and C. Clark, “CubeSat platforms as an on-orbit technology validation
and verification vehicle,” in Pestana Conference Centre, 2010.
[25] http://www.pumpkininc.com/ [Accessed: 18-May-2012].
[26] http://ww1.microchip.com/downloads/en/AppNotes/00777b.pdf
[27] http://documentation.renesas.com/doc/products/tool/apn/res05b0008_r8cap.pdf
[28] David A. Mellis, Arduino. [Online]. http://arduino.cc/ [Accessed: 21-May-2012].
[29] David A. Mellis, Arduino. [Online]. http://arduino.cc/en/Main/ArduinoBoardUno
[Accessed: 18-May-2012].
[30] David A. Mellis, Arduino. [Online]. http://arduino.cc/en/Main/ArduinoBoardDiecimila
[Accessed: 18-May-2012].
[31] http://CubeSatkit.com/ [Accessed: 19-May-2012].
[32] http://www.microchip.com/ [Accessed: 17-May-2012].
38
[33] http://www.pumpkininc.com/content/doc/manual/SalvoUserManual-v3.2.3.pdf
[34] http://arduino.cc/en/Guide/Windows#toc1 [Accessed: 18-May-2012].
[35] S. Cousins, “Welcome to ROS Topics”, Robotics & Automation Magazine, IEEE, 2010,
pp. 13-14.
[36] http://ww1.microchip.com/downloads/en/DeviceDoc/MPLAB_ICD3_UG_51766a.pdf
[37] M. Quigley, K. Conley, B. P. Gerkey, F. Josh, F. Tully, L. Jeremy, W. Rob, N. Y.
Andrew, “ROS: an open-source Robot Operating System,” ICRA Workshop on Open Source
Software, Computer Science Department, Stanford University, Stanford, CA, Willow
Garage, Menlo Park, University of Southern California, 2009.
[38] http://www.ros.org/wiki/ROS/Introduction [Accessed: 21-May-2012].
[39] http://www.ros.org/wiki/ROS/Installation [Accessed: 18-May-2012].
[40] http://www.ros.org/wiki/ROS/Concepts [Accessed: 18-May-2012].
[41] http://www.i2c-bus.org/obscure-problems/ [Accessed: 20-May-2012].
[42] T. Straszheim, B. Gerkey, S. Cousins, “The ROS Build System”, Robotics & Automatio
n Magazine, IEEE, 2011, pp. 18-122.
[43] Q. Yu, H. Wei, M. Liu, and T. Wang, “A novel multi-OS architecture for robot
application,” in Robotics and Biomimetics (ROBIO), IEEE International Conference on,
2011, pp. 2301 –2306.
[44] S. Cousins, B. Gerkey, K. Conley, W. Garage, “Sharing Software with ROS”, Robotics
& Automation Magazine, IEEE, 2010, pp. 12-14.
[45] D. Kononchuk, V. Kandoba, S. Zhigalov, P. Abduramanov, and Y. Okulovsky,
“RoboCoP: A Protocol for Service-Oriented Robot Control Systems,” in Research and
Education in Robotics - EUROBOT 2011, vol. 161, D. Obdržálek and A. Gottscheber, Eds.
Springer Berlin Heidelberg, 2011, pp. 158–171.
[46] C. J. McNutt, R. Vick, H. Whiting, and J. Lyke, “Modular Nanosatellites–
(Plug and Play) PnP CubeSat,” in 7th Responsive Space Conference, Los Angeles, CA,
2009.
[47] Saqib Mehmood, Muhammad Imran Shahzad, "Control of Articulated Robot Arm by
Eye Tracking," Blekinge Institute of Technology, Karlsakrona, Sweden., Master Thesis
MCS-2010-33, September, 2010.
[48] M. Quigley, B. Gerkey, K. Conley, J. Faust, T. Foote, J. Leibs, E. Berger, R. Wheeler,
and A. Ng. ROS: an open-source Robot Operating System. In Open-Source Software
workshop of the International Conference on Robotics and Automation, 2009.
[49] T. Booysen, M. Rieger, and A. Ferrein, “Towards Inexpensive Robots for Science and
Technology Teaching and Education in Africa,” in AFRICON, 2011, 2011, pp. 1–6.
[50] http://www.cubesatshop.com [Accessed: 19-May-2012].
39
[51] K. Buys, S. Bellens, W. Decre, R. Smits, E. Scioni, T. D. Laet, J. D. Schutter, H.
Bruyninckx, “Haptic coupling with augmented feedback between two KUKA Light-Weight
Robots and the PR2 robot arms” Department of Mechanical Engineering, Katholieke
Universiteit, Intelligent Robots and Systems (IROS), IEEE/RSJ International Conference,
25-30 Sept. 2011, Leuven, Belgium, pp. 3031-3038.
[52] http://www.i2cprotocolanalyzer.com/ [Accessed: 19-May-2012].
[53] Jason Axelson, "Design of a CubeSat Payload Interface," University of Hawai, Mānoa
Honolulu, Phd Thesis, 2009.
[54] Alexandru Catalin Munteanu, "Nanosat/ Cubesat Contellation Concepts," Luleå
University of Technology, Luleå, Sweden, Master‟s Thesis 2009:092-ISSN: 1653-0187,
2008-09.
40
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement