A nonlinear friction compensation method using adaptive control and its practical application to an in-parallel actuated 6-DOF manipulator

Abstract

This paper presents a simple and effective nonlinear friction compensation method which is derived from an adaptive control strategy and its practical application to a linear actuator. The proposed adaptive friction compensation method is shown to be equivalent to the reversed integral controller that is easily applied to the conventional PID controller. The reversed integral controller reverses the sign of the integrator output as the sign of the velocity changes. It analyzes how the reversed control action can compensate for friction. The effectiveness of this approach is demonstrated by experiments on a 3-PRPS (Prismatic-Revolute-Prismatic-Spherical joints) in-parallel 6-DOF manipulator. (C) 2001 Published by Elsevier Science Ltd. All rights reserved.