Development of a rule-based controller for robot precision insertion

In the manufacturing industry, precision inserting operations still largely depend on human operations. This is due to the fact that inserting operations entail many difficulties beyond the ability of conventional industrial robots. The purpose of this study is to develop a precision insertion strategy for an articulated robot under vague positional information between the peg and the mating part. In the proposed algorithm, the mating part is mounted on a force/torque sensor which is fixed on a table, and a two-stage insertion strategy based on measured force/torque data is used to guide the peg motion. A calibration algorithm has also been developed to calibrate the coordinate of the force/torque sensor in terms of the robot coordinate. Experimental results have shown that the proposed insertion strategy is indeed useful under various clearances, initial peg positions and chamfer types.