Because of the difficulty of dynamic equations for the inserting operation and the advantage of fuzzy control for easy execution without knowledge of the mathematical models. We used the force feedback signal measured by a force sensor and a fuzzy controller to regulate the position of the peg. The control strategies include two control loops; in one a PID position controller move the peg vague position near to the hole, and in the other the fuzzy controller regulates the final position according to contact force. Between the two control loops we use an index to activate a switch. To verify the proposed control strategy, we performed experiments with a Cartesian manipulator system driven by AC servo-motors. The experimental results reveal that we can insert a peg into a hole with a fitting clearance less than 0.01 mm.
