A Workmanlike Orthogonal-Type Robot with a Force Input Device

Abstract

In this paper, a workmanlike orthogonal-type robot with a force input device is presented. The control system is composed of a force feedback loop, a position feedback loop and a position feedforward loop. The force feedback loop controls the resultant force consisting of tool contact force and kinetic friction forces. The stability criterion of the force control system is briefly discussed. Also, the position feedback loop controls the position in only pick feed direction. The position feedforward loop leads the tool tip along a desired trajectory called Cutter Location data (CL data), in which the feed rate is suitably generated by a fuzzy reasoning according to each model’s curvature. Further, a fine stick-slip motion control strategy is added to the control system to improve the lapping efficiency. The fine stick-slip motion is orthogonally generated to the direction of tool movement. Finally, a force input device is presented for an operator to manually regulate the desired feed rate or the desired polishing force. The force input device allows the robot to realize cooperative motion between the automatic control and the manual control reflecting the operator’s skill. The effectiveness of the robot is examined through experiments.