Automated polishing of an unknown three-dimensional surface

An automatic system for polishing an unknown three-dimensional surface using a passively compliant end-effector mounted on the wrist of an industrial robot is described. As polishing proceeds, the end-effector uses position sensors to measure the misalignment of the robot's wrist from the local surface normal. A personal computer is used to acquire sensory data, to compute the desired configuration of the robot wrist, and to control the robot in a point-to-point mode. Low bandwidth point-to-point control is possible because of the passive compliant movement of the end-effector. Contact with the work surface can be maintained within an angular range of ±8° and a ±10 mm range of normal translational movement. Experimental performance tests show that the polishing system can function well under a variety of working conditions.