AUTONOMOUS SPACECRAFT DOCKING USING MULTI-COLOR TARGETS

摘要

Spacecraft docking requires precision alignment. Traditionally this has been done by astronauts using alignment sights, or offset retro-reflective targets. More recently, teleoperated systems using the same sort of targets have been used. Most experiments with completely autonomous docking systems also rely on similar targets. These systems require high-acuity vision systems, and are computationally expensive. They are also subject to errors and misalignments from the tracking system getting confused by reflective debris, or other spacecraft markings. This paper describes a new docking system currently undergoing testing. This system uses three offset color markers. The markers use bright colors which are ordinarily not seen in an orbital setting. The system tracks the colors at frame rates, and can maintain its lock during changes in lighting conditions. The geometrical and tracking calculations are sufficiently simple that they can all be run on a low-cost commercial microcontroller. Experiments docking a mobile robot, and full 6-DoF experiments planned for a neutral buoyancy tank, are described.