Active compliance control of a PUMA 560 robot

Constrained motion tasks involve interaction forces between the tool and the work-piece and demand certain amounts of compliance at either the tool or at the work-piece. We present a scheme to actively control the necessary compliance of the tool attached to the robot. This scheme allows the operator to specify the center of compliance and the three lateral and three angular compliances. The scheme uses a wrist-mounted, 6 axis force-torque sensor to measure the interaction forces. The necessary compliance is achieved by modifying the motion of the manipulator. This is achieved by programming a force-deflection relationship at the tool tip. This paper discusses the details of the algorithm, development of the control architecture for implementing the proposed scheme on an industrial robot, and real-time experimental results.