Adaptive control of a constrained robot - ensuring zero tracking and zero force errors

A constrained robot is a mathematical model that describes the interaction between a robot and the environment as the robot moves along a prescribed trajectory. The main difficulty in the control of constrained robots is to ensure zero error for the constraint force in addition to accurate trajectory tracking. This study extends the result of Slotine and Li (1991) to design a simple adaptive controller for constrained robots. The proposed controller achieves both control objectives in the presence of dynamic parameter uncertainty. The overall system is proven to be globally stable in the Lyapunov sense. Simulation results are provided to demonstrate the performance of the proposed method.