Implementation of generalized impedance control for robot manipulators

To perform assembly tasks requiring compliant manipulation, the robot must follow a motion trajectory and exert an appropriate force profile while making compliant contact with a dynamic environment. For this purpose, a generalized impedance in the task space consisting of a second-order function relating motion errors and interaction force errors is introduced such that force tracking can be achieved. In the absence of modelling uncertainties, a model-based control laws can be designed to achieve the target impedance. However, in the presence of both parametric uncertainties and external disturbances, a robust control law is needed to realize the generalized impedance. The two control laws are implemented on a multi-degree-of-freedom SCARA robot for inserting a PCB into an edge connector socket. The effectiveness of the two control laws is compared through a computer simulation study. It is found that the robust control law achieve better position and force tracking performance.