Vision-based sensing and control for space robotics applications

The following problems arise in the precise positioning of payloads by space manipulators: 1) the precise measurement of the relative position and motion of objects in the workspace of the robot; 2) the design of a control system, which is robust and performs well in spite of the effects of structural flexibility and oscillations typically associated with space robots. This paper discusses the solution to the measurement problem by a vision system using photogrammatic image processing to determine the motion of objects in real time. Performance characteristics are presented. The control problem is addressed by a new technique dealing effectively with the challenge posed by the noncollocated sensor/actuator configuration on the flexible robot structure. The laboratory implementation of the measurement and control concepts is discussed. Preliminary results validate the concepts.