A Comparison of Classical and Learning Controllers

Abstract This paper focuses on evaluating Locally Weighted Projection Regression (LWPR) as an alternative control method to traditional model-based control schemes. LWPR is used to estimate the inverse dynamics function of a 6 degree of freedom (DOF) manipulator. The performance of the resulting controller is compared to that of the resolved acceleration and the adaptive computed torque (ACT) controller. Simulations are carried out in order to evaluate the position and orientation tracking performance of each controller while varying trajectory velocities, end effector loading and errors in the known parameters. Both the adaptive controller and LWPR controller have comparable performance in the presence of parametric uncertainty including friction. The ACT controller outperforms LWPR when the dynamic structure is accurately known and the trajectory is persistently exciting.