Hardware Testbed for Relative Navigation of Unmanned Vehicles Using Visual Servoing

Mark J. Monda Future generations of unmanned spacecraft, aircraft, ground, and submersible vehicles will require precise relative navigation capabilities to accomplish missions such as formation operations and autonomous rendezvous and docking. The development of relative navigation sensing and control techniques is quite challenging, in part because of the difficulty of accurately simulating the physical relative navigation problems in which the control systems are designed to operate. A hardware testbed that can simulate the complex relative motion of many different relative navigation problems is being developed. This testbed simulates near-planar relative motion by using software to prescribe the motion of an unmanned ground vehicle and provides the attached sensor packages with realistic relative motion. This test-bed is designed to operate over a wide variety of conditions in both indoor and outdoor environments, at short and long ranges, and its modular design allows it to easily test many different sensing and control technologies. The first relative navigation sensing technique evaluated on the testbed is a visual sensor. The visual sensor uses a digital camera and a color statistical pressure snake algorithm running in real-time on an onboard computer to track a target image and determine the relative position and orientation of the target. Non-linear proportional and proportional-integral feedback control laws are developed for the visual servoing problem. The effectiveness of the sensing and control techniques are evaluated on the hardware testbed, and results are shown for both collaborative and non-collaborative targets in real-world test conditions. 307618. We would also like to thank ORION International Technologies for providing a license to the UMBRA software framework.