obstacle avoidance subsystem for an autonomous robot

Download Obstacle Avoidance Subsystem for an Autonomous Robot

Post on 31-Jan-2016

226 views

Category:

Documents

0 download

Embed Size (px)

DESCRIPTION

C

TRANSCRIPT

  • Olivet Nazarene UniversityDigital Commons @ Olivet

    Honors Program Projects Honors Program

    5-1-2011

    Obstacle Avoidance Subsystem for anAutonomous RobotKirstie KingOlivet Nazarene University, kking4@live.olivet.edu

    This Article is brought to you for free and open access by the Honors Program at Digital Commons @ Olivet. It has been accepted for inclusion inHonors Program Projects by an authorized administrator of Digital Commons @ Olivet. For more information, please contact kboyens@olivet.edu.

    Recommended CitationKing, Kirstie, "Obstacle Avoidance Subsystem for an Autonomous Robot" (2011). Honors Program Projects. Paper 7.http://digitalcommons.olivet.edu/honr_proj/7

  • OBSTACLE AVOIDANCESUBSYSTEM FOR AN AUTONOMOUS ROBOT

    By

    Kirstie King

    Honors CapstoneProject

    Submitted to the Faculty of

    Olivet Nazarene University

    for partial fulfillment of the requirements for

    GRADUATION WITH UNIVERSITY HONORS

    May, 2011

    BACHELOR OF SCIENCE

    in

    Computer Engineering

    D . Lc>crr1 I

    3\.,-_"' E. ~ ~ ~ \ \ - ; < l - ~ ~ ~ ~ ~ ~ ~ J Honors Council Chair (printed) Signature

    Honors Counci!Meffi ertprinted) Signature

    f/

  • i

    ACKNOWLEDGEMENTS

    I would like to acknowledge all of the help and mentoring I have received from

    Professor Joseph Makarewicz in understanding how to start designing the software

    architecture for an autonomous system. I would also like to mention Dr. Larry Vail, for

    agreeing to be my official Honors mentor, even though this project wasnt part of his

    department. I would also like to thank all of the seven other teammates I have had

    during the course of this project. Being part of this team was an integral part of

    completing this project.

    FOREWORD

    This is a subproject from within a larger engineering team working together to

    design and implement an autonomous ground vehicle. The report is a compilation of

    the work completed for the teams Design Proposal and Design Report that is applicable

    to the development of the obstacle avoidance subsystem.

  • ii

    TABLE OF CONTENTS

    ACKNOWLEDGEMENTS ........................................................................................................ i

    FOREWORD .......................................................................................................................... i

    LIST OF TABLES .................................................................................................................... iv

    LIST OF FIGURES ................................................................................................................... v

    INTRODUCTION ................................................................................................................... 1

    Problem Definition .................................................................................................. 1

    Background ............................................................................................................. 2

    Sponsoring Organizations ........................................................................... 2

    IGVC Events ................................................................................................. 3

    Problem History .......................................................................................... 4

    REVIEW OF LITERATURE ...................................................................................................... 5

    METHODS ............................................................................................................................ 7

    System Requirements and Constraints ................................................................... 7

    Minimum Design Goals ............................................................................... 7

    Functional Requirements ............................................................................ 7

    Design Alternatives ................................................................................................. 8

    Selection of Design Alternatives ........................................................................... 10

    RESULTS............................................................................................................................. 12

  • iii

    Hardware Connection ........................................................................................... 12

    Overall Software Architecture .............................................................................. 20

    Collision Avoidance Subsystem Software Interface ............................................. 23

    DISCUSSION ....................................................................................................................... 25

    Design Verification ................................................................................................ 25

    Conclusion ............................................................................................................. 26

    REFERENCES ...................................................................................................................... 27

    APPENDICES ...................................................................................................................... 30

    Appendix A: Acronyms .......................................................................................... 30

    Appendix B: Technology/Software Review ........................................................... 30

    Laser Range Finder and Vision Technology .............................................. 30

    Python ....................................................................................................... 31

    Appendix C: Installing SICK Laser Rangefinder Configuration Software ............... 31

    Appendix D: Code Listing: Sensor Interface for Laser Rangefinder ...................... 32

    Appendix E: Code Listing: Obstacle Class.............................................................. 34

    Appendix F: Test run output of LMS Sensor Interface Code ................................ 34

  • iv

    LIST OF TABLES

    Table 1: Changes to Serial Connection ............................................................................. 16

    Table 3: System State from Status Lights ......................................................................... 17

    Table 4: Telegram Structure [15] ...................................................................................... 18

    Table 5: Example of a Complete Telegram (standard devices) [15] ................................. 18

    Table 6: Laser Rangefinder Configuration Order [15] ...................................................... 20

  • v

    LIST OF FIGURES

    Figure 1: Power and Serial Communication Cables [10]................................................... 12

    Figure 2: Power Supply Plug [10] ...................................................................................... 13

    Figure 3: Layout of the Serial Connection Plug [10] ......................................................... 13

    Figure 4: Wire Crossing Between TxD and RxD [10] ......................................................... 14

    Figure 5: RS-232 Pin Out ................................................................................................... 16

    Figure 6: Laser Rangefinder Status Lights [10] ................................................................. 17

    Figure 7: General Telegram Data Format ......................................................................... 18

    Figure 8: Software Architecture ........................................................................................ 21

    Figure 9: Laser Rangefinder Screenshot ........................................................................... 25

  • vi

    ABSTRACT

    This research project details the design and implementation of the Obstacle

    Avoidance Subsystem for the Tigertron autonomous robot. This subsystem is designed

    to function as a smaller part of the whole Software Architecture and has the purpose of

    detecting, through use of a Laser Rangefinder, obstacles in the vehicles environment.

    Once the hardware is set up and configured, the Tigertrons central software control

    architecture requests data from the Laser Rangefinder through a serial communication

    channel. This data is converted into objects that represent obstacles in the form of

    polar coordinates. These objects are stored in a container so the central control

    architecture can determine the best route to avoid these obstacles while still navigating

    to route waypoints.

    Keywords

    Autonomous, Behavior Layer, Coordination and Planning, Intelligent Ground Vehicle

    Competition, Laser Management System, Laser Rangefinder, Obstacle Avoidance

    System, Python Programming Language, Real-time System, RS-232, Serial

    Communication, SICK LMS, World Modeling

  • 1

    INTRODUCTION

    It is a misconception with some that autonomous is synonymous with artificially

    intelligent. Autonomous is derived from the ancient Greek word

    (autonomos), which is made up of the words (auto), meaning "self," and

    (nomos), meaning "law." Putting these two words together provides the semantic

    meaning: "one who gives oneself his own law." In robotics autonomy merely means

    independence of controlthat a robot can perform s

Recommended

View more >