Adaptive control techniques for friction compensation

In this paper, we design two adaptive controllers for a second-order mechan ical system which incorporates frictional effects such as Coulomb, static, Stribeck, and Viscous friction. First, we design a modular position trackin g controller that can accommodate a variety of adaptive update laws. The pr oposed controller is shown to compensate for uncertainty associated with th e friction parameters which appear linearly in the model. In the second con trol scheme, we show how a Lyapunov-based adaptive position setpoint contro ller can be designed to compensate for parametric uncertainty throughout th e mechanical system including the Stribeck effect related constant which do es not appear linearly in the model. Experimental results are provided to i llustrate the performance of the proposed controllers. (C) 1998 Elsevier Sc ience Ltd. All rights reserved.