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Development of Autonomous Cargo Transport for an Unmanned Aerial Vehicle Using Visual Servoing. Noah Kuntz and Paul Oh Drexel Autonomous Systems Laboratory Drexel University, Philadelphia, PA. Motivation.
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Development of Autonomous Cargo Transport for an Unmanned Aerial Vehicle Using Visual Servoing Noah Kuntz and Paul Oh Drexel Autonomous Systems Laboratory Drexel University, Philadelphia, PA
Motivation Helicopter cargo transport using sling-load systems allow delivery of payload to otherwise unreachable areas • Helicopter cargo transport requires dangerous sling-load attachment maneuvers • Cargo must often be delivered to high risk areas, endangering the crew UAVs CAN FIX THIS! HOWEVER Pictures source: http://www.mccoy.army.mil/ReadingRoom/Triad/06112004/Sling-load%20Sinai.htm
Proposed Solution • Autonomous air cargo transport via unmanned helicopter • No risk to a ground crew at the time of cargo attachment and detachment • No risk to a flight crew while flying through high risk environments • Flexible, targeted delivery of small quantities of cargo, using current unmanned helicopters with approximately 15-20 lbs of payload • Potential for adaptation to full scale helicopters
Research Path • Establish load carrying ability of unmanned helicopter platform • Set up hardware-in-the-loop test environment for cargo pickup system • Develop and test the cargo pickup system in test environment • Refine system and retest • Flight test the system once sufficiently developed
GPS Waypoint Navigation Takeoff Track Cargo Hook Cargo 2 4 1 3 Concept of Operations SR-100 is capable of Autonomous takeoff. When criteria are met for proximity to the target, the hook is servoed through the target loop. Autonomous hovering and GPS waypoint navigation is integral to the SR-100’s control package. Tracking is performed with visual servoing using onboard camera and computer.
Concept of Operations 5 6 7 Increase Altitude GPS Waypoint Navigation Unhook Cargo The cargo will then be lifted off the ground. GPS navigation will occur again. The cargo will be set on the ground and the hook retracted.
Challenges • Overall “Mobile Manipulation” problem • Tracking target under variant lighting • Tracking while helicopter wanders • Servoing the hook fast enough • Overall weight constraints
Potential Cargo • Medicine • Specialized parts or tools for in-field repair • UGVs for bomb disposal or surveillance • Such as the Bombot, a low cost compact bomb disposal robot manufactured by the West Virginia High Technology Consortium (WVHTC) Foundation Pictures source: http://robotgossip.blogspot.com/2006/01/bombot-to-be-built-in-west-virginia.html
Helicopter Cargo Carrying Tests • Test cargo was a small remote control UGV, for potential UGV/UAV teaming missions • Computer controlled takeoff, flight, and landing • Demonstrated suitability of the SR-100 unmanned helicopter for light cargo transport SR-100 platform proves capable
Systems Integrated Sensor Test Rig (SISTR) • 6DOF capable with velocity control • Environmental simulation including lighting control • Allows approximate recreation of flight conditions
SISTR Flight Data Playback • Recreate helicopter motion under controlled condition • Encoder data validates the gantry velocity controller SISTR replicates flight movements
Mechanism • 2DOF stepper motor camera PTU for high speed and precision • 2DOF hook PTU for high torque, low cost, and light weight
Vision • Structured lighting approach used for initial testing • Target uses krypton bulbs as fiducials, with high IR emission • IR band-pass filter removes non-infrared light • Threshholding operation isolates fiducials which are tracked using image-based pose regulation Simple tracking for low computation / high speed
Testing Procedure Gantry replays recorded helicopter velocities Target is placed in each of nine positions within 20 cm (GPS accuracy) from ideal
Results • Near-miss conditions could be eliminated with a faster hook pan-tilt unit • Success rate of ~83% should be possible with minor improvements
Contributions + Future Work • Autonomous cargo pickup shows promise • Faster servos will be tested to reduce near-miss events • Results will be confirmed with flight tests
Acknowledgements • National Science Foundation • US Army Telemedicine Advanced Technology Research Center (TATRC) • Piasecki Aircraft Inc • For more info please see: • http://www.pages.drexel.edu/~nk752/