LRC Presentation


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Presentation on Selene, the University of Surrey Lunar Rover, to ESA at ESTEC, NL.

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LRC Presentation

  1. 1. Selene: The Surrey Lunar Rover Chris Brunskill Team Captain Email: Academic Advisor Dr. Vaios Lappas email: July 8, 2008
  2. 2. Small Satellite Centre of Excellence <ul><li>University of Surrey, Faculty of Engineering & Physical Sciences </li></ul><ul><ul><li>Highest (5*) national research rating </li></ul></ul><ul><ul><li>Ranked #1 or #2 in Electronic Engineering in UK </li></ul></ul><ul><li>Surrey Space Centre </li></ul><ul><ul><li>International reputation as innovator and pioneer </li></ul></ul><ul><ul><li>10 academics, 44 researchers </li></ul></ul><ul><ul><li>Undergraduate and postgraduate teaching </li></ul></ul><ul><ul><li>Approx 50 Master degrees per year </li></ul></ul><ul><ul><li>Approx 10 Doctoral degrees per year (total this year: 50) </li></ul></ul><ul><li>Academic Research Groups </li></ul><ul><ul><li>Remote Sensing Applications, Sensors and Instrumentation </li></ul></ul><ul><ul><li>Space Robotics , Autonomy and Interplanetary Exploration </li></ul></ul><ul><ul><li>Data handling, Networking and Systems-on-a-Chip for Space Systems </li></ul></ul><ul><ul><li>Astrodynamics, Space Vehicle Control , Propulsion </li></ul></ul><ul><ul><li>Space Environment and Effects </li></ul></ul><ul><ul><li>RF Technology and Autonomy </li></ul></ul>
  3. 3. The Surrey Philosophy <ul><li>Practical: Experiment and Testing </li></ul><ul><li>‘ Can do’ attitude </li></ul><ul><li>Interdisciplinary approach </li></ul><ul><li>Low cost, COTS and be smart (small satellite paradigm) </li></ul>
  4. 4. Selene: The University of Surrey Team <ul><li>Students </li></ul><ul><ul><li>Chris Brunskill (Me) - PhD – Team leader, systems tech lead/mobility </li></ul></ul><ul><ul><li>Beatrice Smith - MSc – Systems architect, mobility </li></ul></ul><ul><ul><li>Sam Humphrey - MEng – RF and Comms </li></ul></ul><ul><ul><li>Michel Makhlouta - MSc – Vision-based navigation </li></ul></ul><ul><ul><li>Akhmer Ahmad - MSc – Robotic arm </li></ul></ul><ul><ul><li>Gareth Meirion-Griffith - MSc – Mechatronics </li></ul></ul><ul><ul><li>Shakeel Baig - MSc – Power systems </li></ul></ul><ul><li>Academics Advisor </li></ul><ul><ul><li>Dr Vaios Lappas, Senior Lecturer in Space Vehicle Control </li></ul></ul><ul><li>Academic Co-advisors </li></ul><ul><ul><li>Dr. E. Moxey </li></ul></ul><ul><ul><li>Dr. M. Saaj </li></ul></ul><ul><ul><li>Dr. Y. Gao </li></ul></ul><ul><ul><li>Dr. P. Newman (Oxford) </li></ul></ul>
  5. 5. Lunar Robotics Challenge <ul><li>Descend into a crater (Traversing slopes of up to 40°) </li></ul><ul><li>Locate and collect samples </li></ul><ul><li>Ascend out of the crater (Traversing slopes of up to 40°) </li></ul><ul><li>Return to the lander </li></ul><ul><li>Deposit Samples (oops!) </li></ul>
  6. 6. The Surrey Proposal <ul><li>Convert a Mobile Robots Pioneer 3-AT to a tracked design suited to use on lunar-type regolith </li></ul><ul><li>Deploy an on-board nanorover to provide a communications relay between the lander and the rover, also provides a video link to aid with localisation </li></ul>
  7. 7. MOBILITY Kåre Halvorsen - Hexapod NASA – Sojourner, MER, MSL wheel comparison Lynxmotion -Tri-Track Chassis
  8. 8. Traction <ul><li>Maintaining contact with the ground while providing forward thrust </li></ul><ul><li>Numerous factors determine the percentage of torque from the motors transferred to forward motion </li></ul><ul><ul><li>Slip </li></ul></ul><ul><ul><li>Sinkage </li></ul></ul><ul><ul><li>Mass </li></ul></ul><ul><ul><li>Wheel/track contact area </li></ul></ul><ul><ul><li>Terrain properties: Soft? Hard? Loose? </li></ul></ul>
  9. 9. Traction <ul><li>Primary focus of design is to maximise traction </li></ul><ul><li>Therefore a tracked design requires the largest ground contact area possible within the design limitations </li></ul>
  10. 10. Traction <ul><li>Grousers also help </li></ul>
  11. 11. Qualisys Motion Capture Tool <ul><li>Motion capture </li></ul><ul><li>Measure position of wheels or tracks in relation to the vehicles motion with sample rates in the 100’s of Hz </li></ul><ul><li>IR cameras detect the IR reflectors placed on the vehicle </li></ul><ul><li>PC tracks the motion of the reflectors and maps these on screen </li></ul>
  12. 12. Qualisys Equipment
  13. 13. Qualisys Equipment
  14. 14. Pioneer 3-AT
  15. 15. Spec <ul><li>4 wheel drive, skid steering mobility system </li></ul><ul><li>Highly suited to off-road use </li></ul><ul><li>Out of the box relatively suited to wet or dirty environments </li></ul><ul><li>Completely enclosed chassis (other than exhaust fan grating) </li></ul><ul><li>3 batteries providing 3-6 hours run time </li></ul><ul><li>27kg base weight </li></ul><ul><li>0.7m/s top speed </li></ul><ul><li>Capable of climbing 35° slopes, climbing 90mm sills </li></ul><ul><li>On board computer (allows for in-situ telemetry processing) </li></ul>
  16. 16. Development Equipment <ul><li>Robotic Arm </li></ul><ul><ul><li>5 DoF, gripper tool, 200-step stepper motors on each joint </li></ul></ul><ul><li>Stereo Camera </li></ul><ul><ul><li>752x480 pixel resolution, range of up to approx. 8m, on-board processing processor </li></ul></ul><ul><li>LIDAR </li></ul><ul><ul><li>Up to 3D mapping of environment </li></ul></ul>
  17. 17. Relay Nanorover <ul><li>Deployable, repositionable base to provide mission aid and assistance </li></ul><ul><li>Relays RF comms when primary rover is inside the crater – will act as a 802.11 wifi accesspoint/meshing </li></ul><ul><li>Provides an additional monitoring point using an on-board camera </li></ul><ul><li>Video stream helps with localisation and navigation </li></ul>
  18. 18. Relay Nanorover
  19. 19. Relay Nanorover
  20. 20. Camera View
  21. 21. Prototype 1 <ul><li>Need a 0.06m 2 contact area for a approx. 40° incline </li></ul><ul><li>Wheelbase approx. 40cm </li></ul><ul><li>Track width of 75mm (COTS track elements) </li></ul><ul><li>Total contact area of: 0.06m 2 ! </li></ul>
  22. 22. First design
  23. 23. First Design
  24. 24. Problems! <ul><li>Obstacle clearance height significantly reduced </li></ul><ul><li>The infamous “flipping” technique! </li></ul>
  25. 25. The Real Deal - Selene
  26. 26. Deployment Mechanism <ul><li>Two options </li></ul><ul><ul><li>Internal gearing </li></ul></ul><ul><ul><li>External gearing/belt </li></ul></ul><ul><li>External is simpler </li></ul><ul><li>Internal provides better dust protection </li></ul><ul><li>Requires </li></ul><ul><ul><li>New hub and bearing housings </li></ul></ul><ul><ul><li>Pitch control servo </li></ul></ul>
  27. 27. Deployment Mechanism – Pitch Control
  28. 28. Deployment Mechanism – Pitch Control
  29. 29. Deployment Mechanism – Replacement Hub
  30. 30. Deployment Mechanism – Complete Hub Control System
  31. 31. Deployment Mechanism – Complete System (1 st iteration)
  32. 32. Track Deployment
  33. 33. Power <ul><li>3x 12V Batteries </li></ul><ul><li>252WHrs </li></ul><ul><li>Under full load Pioneer uses approx. 57W </li></ul><ul><li>Using the arm takes approx. 50W </li></ul><ul><li>Power shouldn’t be an issue </li></ul><ul><ul><li>(unless we get lost…) </li></ul></ul>
  34. 34. Navigation and OBC <ul><li>OBC is a normal x86 computer </li></ul><ul><li>Debian Linux OS </li></ul><ul><li>Allows for quick development of software </li></ul><ul><li>Mobile Robots provide the ARIA C++ API </li></ul>
  35. 35. Navigation and OBC <ul><li>Stereoscopic greyscale VIS/NIR camera </li></ul><ul><li>Weatherproof (dustproof version also available) </li></ul><ul><li>752x480 resolution </li></ul><ul><li>nDepth PC104+ expansion board </li></ul><ul><li>Attaches directly onto OBC </li></ul><ul><li>The built in processor takes most of the image processing stress off the PC CPU </li></ul>
  36. 36. Navigation and OBC <ul><li>nDepth card provides disparity maps and depth info directly to the OBC </li></ul><ul><li>Accurate to within approximately 10% for ranges of 0.7-7.6m </li></ul><ul><li>Provides live video with depth info on-screen </li></ul>
  37. 37. Navigation and OBC
  38. 38. Navigation and OBC
  39. 39. Navigation and OBC <ul><li>Dead Reckoning and localisation systems: </li></ul><ul><ul><li>IMUs </li></ul></ul><ul><ul><li>Inclinometers </li></ul></ul><ul><li>Additional Monoscopic colour cameras for sample searching </li></ul><ul><ul><li>One on nanorover </li></ul></ul><ul><ul><li>One (or more) on rover </li></ul></ul>
  40. 40. Robotic Arm <ul><li>6 degree of freedom arm </li></ul><ul><li>Gripper end effector </li></ul><ul><li>Converted to scoop tool </li></ul><ul><li>Control software developed using ARIA C++ API </li></ul>
  41. 41. Robotic Arm
  42. 42. Development Lab
  43. 43. Conclusions <ul><li>Conversion of a Pioneer 3-AT 4wd robot to a tracked rover </li></ul><ul><li>Tracks developed to provide as much traction as possible </li></ul><ul><li>Deployment of a relay nanorover, doubles as a monitoring post from outside the crater </li></ul><ul><li>Dextrous robotic arm used for sample collection </li></ul><ul><li>Stereo Vision primary navigation system </li></ul>
  44. 44. Questions