Adaptive Trajectory Control of Robot Arm Based on Smooth Projection Adaptive Law and Nonlinear friction Compensation (original) (raw)

This paper proposes an adaptive trajectory control method for a 2DOF planar rigid link robot arm with arbitrary link length. The transient response can be improved by a dynamic certainty equivalent controller with nonlinear friction compensator and a dead zone adaptation law to be robust to bounded friction compensation error. Also, the adaptation law accompanies with a smooth projection algorithm which not only confines adjustable parameters of adaptive controller into a certain convex set to guarantee a positive definiteness of estimated inertia matrix but also ensures the differentiability of those. The convex set is designed by taking into account the existence region of the parameters of the robot arm with expected loads.