Robotic Compliant Motion Control for Aircraft Refueling Applications

摘要

A promising Air Force application of robotics technology is the refueling of aircraft or spacecraft with a robotic manipulator. The refueling task is fundamentally a component assembly task, and like many other assembly tasks, successful completion requires compliance between the manipulator and the environment for success. Compliant motion control techniques, such as impedance control, use force feedback to generate active compliance in the robot manipulator. In this thesis a compliant motion control environment was established, and a simplified, preliminary version of an impedance control law was implemented. The compliant motion environment employs three digital processors in a hierarchial control structure to command a PUMA 560 robot arm. Applied force and moment information are provided by a wrist mounted, three axis force sensor. An original method was developed to transform forces and moments acting on the tool, measured in the sensor frame, to the cartesian world coordinate frame. This method eliminates the forces and moments caused by the tool weight from the measured values. The concept of impedance control law is presented. The simplified impedance is explained, and motivated as the basis for compliant motion control. The theoretical development leading to the simplified impedance control law was used to provide active compliance for links 2 and 3 of the PUMA arm. The remaining four links of the PUMA were not actively used in the impedance control experiment. Theses. (FR)