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Applications of Knowing “Where am I” Two Examples:. Prospect Eleven: Princeton University’s Autonomous Vehicle Entry 2005 DARPA Grand Challenge. CoPilot|MinETA Real-Time Dynamic Minimum ETA Sat/Nav. Thursday, February 6, 2006 National Physical Laboratory Teddignton, Middlesex, UK.
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Applications of Knowing “Where am I” Two Examples: Prospect Eleven:Princeton University’s Autonomous Vehicle Entry 2005 DARPA Grand Challenge CoPilot|MinETAReal-Time Dynamic Minimum ETA Sat/Nav Thursday, February 6, 2006 National Physical Laboratory Teddignton, Middlesex, UK Alain L. Kornhauser Team Leader, Prospect Eleven Professor, Operations Research & Financial Engineering Princeton University Co-founder & Board Chair, ALK Technologies, Inc.
Prospect Eleven: The Making, Testing and Running ofPrinceton’s Entry in the 2005 DARPA Grand Challenge Alain L. Kornhauser Team Leader, Prospect Eleven Professor, Operations Research & Financial Engineering
The DARPA Grand ChallengeDefense Advanced Research Projects Administration • DARPA Grand ChallengeCreated in response to a US Congressional and DoD mandate, it was a field test intended to accelerate research and development in autonomous ground vehicles that will help save lives on the battlefield. The Grand Challenge brought together individuals and organizations from industry, the R&D community, government, the armed services, academia, students, backyard inventors, and automotive enthusiasts in the pursuit of a technological challenge. • The First Grand Challenge: Across the Mojave, March 2004From Barstow, California to Primm, Nevada offered a $1 million prize. From the qualifying round at the California Speedway, 15 finalists emerged to attempt the Grand Challenge. However, the prize went unclaimed as no vehicles were able to complete the difficult desert route. • The 2005 Grand ChallengeOctober 8, 2005 in the desert near Primm. Prize increased to $2 million.
Constraints Objective • Very little budget • Enrich the academic experience of the students Guiding Principles • Simplicity
Homemade “Unlike the fancy “drive by wire” system employed by Stanford and VW, Princeton’s students built a homemade set of gears to drive their pickup. I could see from the electronics textbook they were using that they were learning as they went.” http://www.pcmag.com/slideshow_viewer/0,1205,l=&s=1489&a=161569&po=2,00.asp
Teamwork Team Leader Alain Kornhauser*71P03 Organizational Systems Rachel Blair’06 Real-time Decision System Andrew Saxe’08 Computing Systems Anand Atreya’07 Mechanical Systems Gordon Franken’08 Electronic Systems Bryan Cattle’07 Object Detection System Brendan Collins’08 Control Systems Scott Schiffres’06 Planning Systems Josh Herbach’08
Mechanics Design and Fabrication of: • Vehicle Actuators • Steering • Brakes • Transmission • Sensor Housings • Stereo Camera • GPS Antennae • System Protection • Shock-absorbing computers • Secure installation of components
Vehicle Actuators Rotary Encoder • Steering • Motor from Bosch cordless drill. • Modified gears mounted directly to steering wheel. • Rotary encoder used for position feedback. • Brakes • Bicycle brake cable used to depress pedal. • Motor-driven linear actuator. • Load-cell used for tension feedback. • Also: pneumatic e-brake, for fail-safe operation. • Transmission • Ability to shift from forward to reverse. • Not used due to several issues: • Slow actuation • Difficulty interfacing with vehicle transmission • Not open up an Achilles heel. Load cell Steel Gears bike cable brake pedal motor Drill motor
GPS Antennae • 4 GPS receivers • Need good location on top of vehicle for best data. • Wooden boom also supported rotating beacon Sensor Housings • Stereo Camera • Camera rated for “indoor office use only” !!! • Water & air tight enclosure • Mounts for photographic filters
System Protection • Shock Absorption for computers. • Old way: Computers were wrapped in foam. • New way: Computers are rack-mounted on shock-isolating feet. • Secure installation of other components. • Batteries, wires, power supplies, air compressor… • The “shake test” Shock-absorbing feet
Stereo Vision System • Principle of Operation: Difference between two cameras gives depth information • Steps: • Compute disparity image • Find obstacles in each column • Approximate with rectangles • Filter in time domain
Challenges • Quantization • Noise • Lighting condition • Field of view • Occlusion • Range
The left camera sees: Point Grey Bumblebee Focal Length: 4mm Resolution: 640x480 Black & White
The right camera sees: Point Grey Bumblebee Focal Length: 4mm Resolution: 640x480 Black & White
Yielding a disparity map: Intensity indicates distance: the lighter, the closer White indicates an invalidated location.
Processing in each column: Intensity indicates confidence that an obstacle exists at that location. A darker line indicates a higher confidence.
Bounding with rectangles: Darker rectangles indicate higher confidence.
Data Representation vs. Reference: http://www.darpa.mil/grandchallenge/TechPapers/Stanford.pdf
Blind-Man’s Cane Approach: Find best instantaneous velocity vector (heading and speed) within visible cone ahead. ? Desired V Navigation
Distance Shoot the Gap V Angle Gap Identification
Not without Problems May Get Squeezed Yippes! ‘Gotta’ Reverse Examples of “Shoot the Gap”
Interfacing to Existing Vehicle Data Existing electronic information available on ’05 GMC Canyon: • Engine status – temp, RPM, diagnostic codes,... • Transmission – what gear are we in? 4WD on/off • Car traction control – are wheels slipping, are we really moving? • Wheel speed/odometry – how far have we moved? how fast? • Throttle is electronic All monitored & used by Prospect Eleven
Feedback Control Systems Speed Control Module: • Receives desired speed from Navigation • Decides how to modulate throttle and brake • Requirements • Gracefully reach and maintain desired speed • Smooth acceleration and braking • To minimize skidding on loose sand wet grass • Strict adherence to speed limit • Minimize overshoot Steering Control Module • Receives desired heading angle and speed from Navigation • Converts to desired steering wheel angle • Constrains wheel angle as function of speed to avoid roll-over. • Control Coefficients tuned to trade off response and overshoot
Speed Control -- Implementation Speed Control Percent Throttle Desired Speed • Proportional Integral Control • Output = KPev + ∫KIevdt + KD (dev∕dt) • Where evelocity = Vdesired – Vcurrent • KP term deals with the bulk of error • KI integrates up error to eliminate steady state error • KD reduces overshoot and ringing by slowing response Percent Brake Tension Current Speed Latest Speeds
Why P11 stopped after 9.4 miles • We store a list all obstacles we are currently concerned about • Each time a new obstacle is received, we add it to this list • Each obstacle needs to have its relative position updated each time we get new vehicle position information • It gets these updates by subscribing to the RelativeFrameUpdated event • When we have passed an obstacle by more than twenty feet, we remove it from the list • However, we were not unsubscribing the obstacle from the RelativeFrameUpdated event Thus, nine miles down the road, our computer was still processing a bush it saw near the beginning of the course! C# is a powerful language, but it has to be used carefully
The Day Before 2005 Grand Challenge Event DAPRPA Grand Challenge Event, October 07, 2005
The DARPA Grand Challenge Event Team 2005 Grand Challenge Event DAPRPA Grand Challenge Event, October 08, 2005 L2R: Rachel Blair’06, Dan Chiou’05, Prof. Alain Kornhauser*71 P03, Ben Essenburg’05, Bryan Cattle’07, Josh Herbach’08. Jeff Jones*05, Kamil Chihoudy’06, Scott Schiffres’06, Anand Atreya’07; Launch Team: Andrew Saxe’08, Brendan Collins’08, Gordon Franken’08
The Launch of Prospect Eleven 2005 Grand Challenge Event DAPRPA Grand Challenge Event, October 08, 2005
Return of Prospect Eleven @ 8 Mile Mark 2005 Grand Challenge Event DAPRPA Grand Challenge Event, October 08, 2005
Approaching Beer Bottle Pass 19:02 2005 Grand Challenge Course DAPRPA Grand Challenge, Unfinished Business, October 31, 2005
Beer Bottle Pass 19:10 PST 2005 Grand Challenge Course DAPRPA Grand Challenge, Unfinished Business, October 31, 2005
The Assent: 17:00 Rerun to Beer Bottle Pass DAPRPA Grand Challenge, Unfinished Business, November 1, 2005
The Assent: 17:01 Rerun to Beer Bottle Pass DAPRPA Grand Challenge, Unfinished Business, November 1, 2005
12:25 2004 Grand Challenge Course DAPRPA Grand Challenge, Unfinished Business, November 2, 2005
14:26 2004 Grand Challenge Course DAPRPA Grand Challenge, Unfinished Business, November 2, 2005
The Finish 18:44 2004 Grand Challenge Course DAPRPA Grand Challenge, Unfinished Business, November 2, 2005 L2R: Prof. Alain Kornhauser*71 P03, Andrew Saxe’08, Bryan Cattle’07, Scott Schiffres’06
Prospect Eleven’sUnfinished BusinessOctober 31-November 2, 2005DARPA Grand Challenge ’04 & ’05 Courses Finish, ’05 Course GPS Tracks and Timing Maps DAPRPA Grand Challenge, Unfinished Business, October 31, 2005
14:16:03 2:23 remove rubble blocking I-15 underpass GPS Tracks & Timing of Prospect Eleven’s Autonomous run of the 05 GC Course 10/31/05 12:42:35 4:40 Pause 12:33:51 1:19 Pause 13:16:05 1:32 Rejoin course 13:18:53 1:10 Pause 15:13:31 1:30 Wait for traffic to clear on NV 161 11:29:52 42:00 Pull chase car out of mud 11:15:15 5:14 Pause at ranch, go thru gate 10:48:04 3:45 Open & pass thru gate 16:03:07 1:53 Pause 18:02:50 2:08 Pause 10:53:33 2:15 Pause 16:07:48 4:32 to take pictures 16:12:50 11:44 negotiate bulldozed area 10:37:37 5:54 Open & pass thru gate 18:20:53 38:50 prepare inside video 16:31:17 2:12 Survey another bulldozed area 19:00:21 – 0:56 Adjust Camera 19:02:53 – 1:52 Wait for chase car 8:20:55 5:20 Pictures at Primm return 9:52:53 8:14 Open gate & pass through Start 7:53:30 PST Finish 19:35:49 Elapsed Time 11:43:49 Pause Time ~2:55:49 Autonomous Time 8:48:59 8:44:48 1:10 Pause 8:31:42 8:53 Take down fence & pass through
Blue: 8:00 Outbound 11/2 Lake dried sufficiently, no deviation required. Red: 8:00 Outbound 10/31 Deviation to avoid “lake” Yellow: 16:30 Return 10/31 Deviation to avoid “lake” GPS Tracks & Timing of Prospect Eleven Diverting Around Not-so-dry Lake 05 GC Course 10/31/05
Return to Beer Bottle Pass GPS Tracks of return to Beer Bottle Pass 11/01/05 DAPRPA Grand Challenge, Unfinished Business, November 1, 2005
Return to Beer Bottle Pass 2005 Grand Challenge Course, 1.9 miles GPS Tracks & Timing of Prospect Eleven’s Autonomous run up then back down Beer Bottle Pass 11/02/05 Start Down: 17:10:17 End Up: 17:04:48 Duration: 0:10:21 End Down: 17:18:04 Duration: 0:7:47 DAPRPA Grand Challenge, Unfinished Business, November 1, 2005 Start Up: 16:54:27
GPS Tracks & Timing of Prospect Eleven’s Autonomous run of the 04 GC Course 11/02/05 7:28:33 4:35 negotiate bulldozed area 8:39:13 11:50 take pictures 8:34:01 4:30 take pictures 9:42:26 1:50 take pictures 10:04:59 2:07 take pictures 7:08:36 Start ’04 GC Course 10:28:11 3:20 take pictures 7:55:26 33:08 Divert to get gas for P11 10:13:43 2:10 cross road DAPRPA Grand Challenge, Unfinished Business, November 2, 2005
GPS Tracks & Timing of Prospect Eleven’s Autonomous run of the 04 GC Course 11/02/05 12:05:25 0:30 Xing CA 127 12:08:00 2:00 take pictures 10:57:13 6:30 take pictures 12:38:03 2:17 take pictures 15:10:10 2:04 Inspect burial monument 14:44:13 2:47 take pictures 12:19:37 1:50 take pictures 12:53:36 0:54 Pause 13:08:54 1:05:56 Fix steering encoder 14:33:15 2:45 take pictures 14:50:xx 4:00 Avoid Washout in 4 spots DAPRPA Grand Challenge, Unfinished Business, November 2, 2005