Compliance Control of Tele-Robot

Abstract

Compliance control is essential for tasks involving interaction of the robot with the environment with contact forces e.g. sliding on an inclined plane, drawing on a rigid surface, opening the lid of a box etc. Pure position control is not sufficient for such tasks since a small variation in relative position at the contact surface may generate large contact forces which may damage the environment or manipulator itself. Compliant motion may be produced either by passive mechanical compliance built in to the manipulator, or by an active compliance implemented in the control servo loop. The second method, involving position and force control of the manipulator end-effector in mutually orthogonal directions, has been the focus of this work. In this work "Compliance Control Algorithm" module has been developed which takes the task as the input and generate Position Path and Force Profile. These aforementioned paths and profiles are further given to a Hybrid Controller to achieve compliant motion. The algorithm has been tested by developing a code for the Compliance algorithm and using a PUMA560® dynamic model in MATLAB®. Selected tasks have been performed in simulation to evaluate the performance of the algorithm. Subsequently, the algorithm has also been implemented on Tele--Robot, developed by DRHR, BARC. The results obtained from the Tele-robot system indicate the successful completion of some planned tasks which required simultaneous position and force-control. The results show that the method achieves stable and accurate control of force and position trajectories for a variety of test conditions.