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Gyre 2: Evaluation of Control Techniques for Autonomous Free-Floating Robots. January 20, 2007 Seattle Robotics Society D. Bliss, A. Lacenski, M. Dockrey. Goals. Followup to GYRE 1, which established the best image processing algorithm, but did not demonstrate closed-loop control
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Gyre 2: Evaluation of Control Techniques for Autonomous Free-Floating Robots January 20, 2007 Seattle Robotics Society D. Bliss, A. Lacenski, M. Dockrey
Goals • Followup to GYRE 1, which established the best image processing algorithm, but did not demonstrate closed-loop control • Evaluated four control algorithms: naïve hysteresis, proportional, PI, and PID • Tested aboard NASA’s new C-9 microgravity aircraft in August 2006.
History • Formed in 2001 • Accepted in 2002, postponed flight due to hardware and documentation issues • GYRE 1 accepted and flew in 2003 • Not accepted in 2004 • Accepted in 2005, but program postponed due to aircraft issues • Flew in 2006 • DONE!
About the GYRE platform • 50lbs, 14” cube (NASA requirements) • Free floats within aircraft • 3 onboard computers • National Instruments FieldPoint interface • 12 cold gas thrusters using air • 3 orthogonal cameras • Lithium-polymer batteries
Onboard Computers • Comell Taiwan LV-671M single-board computers, mini-ITX • Intel Pentium-M 1.6, ~2 GIPS, 128MB RAM, 1GB CompactFlash • Cardbus Firewire interface for high-speed video • Mini-PCI 802.11b with external antennas • Onboard 100mbps Ethernet • Serial interface to NI FieldPoint
National Instruments FieldPoint • A general-purpose industrial interface system • One network module, up to 64 I/O modules • Using FP-PG-522 pulse generator modules • Allows all hard realtime to be done in FieldPoint, no need for realtime OS on SBCs
Cold Gas Thruster System • Two 1.8L tanks at 4500 psi • Regulators on each tank reduce to 200 psi (100 psi for 2006 flights) • Low-side air manifolded and distributed to twelve high-speed control valves with attached custom CNC-machined thrusters • Minimum thrust bit 30 msec, about 0.06 N-S • Continuous thrust about 2N
Onboard Cameras • Firewire • TI chipset • 640x480x30fps • Custom CNC-machined enclosures • Image recognition, feature extraction, motion vector extraction, and compensation done by onboard SBCs, one per camera
Lithium-Polymer Batteries • The first rule of LiPo batteries: • DON’T USE LIPO BATTERIES • 28V, ~3AH, ~45m runtime • Horror stories • But, great power density!
Onboard operation • Control laptop • Canon GL2 video camera for data collection • Two operators
Questions? • David Bliss • dbliss@u.washington.edu • http://depts.washington.edu/gyre