Impedance control strategy for robotic assembly tasks

An impedance control scheme is developed for robot manipulators performing assembly tasks which require interactions with the environment. The specification of the target impedance is given in terms of a desired motion trajectory, a desired interaction force trajectory, and a second-order impedance function relating the motion errors and the interaction force errors. The proposed scheme is applied to a SCARA robot for performing the task of inserting a PCB into an edge connector. By considering the constraints encountered during the assembly, a sequence of carefully planned target impedances are suggested to cater for the various environmental characteristics. With this assembly strategy, superior motion tracking performance can be achieved together with acceptable interaction force response. Experimental results have demonstrated the effectiveness of the proposed scheme. In comparison, results show that purely position control methods are not suitable for assembly tasks.