ROBUST ADAPTIVE STICK-SLIP FRICTION COMPENSATION

In this paper, a robust adaptive tracking control scheme is proposed for compensation of the stick-slip friction in a mechanical servo system. The control scheme has a sliding control input to compensate friction forces. The gain of the sliding control input is adjusted adaptively to estimate the linear bound of the stick-slip friction. By introducing the sliding control input, the global stability and the tracking error asymptotic convergence to the predetermined boundary are established via Lyapunov's stability theorem. The proposed scheme is shown to be robust to variations of the system and/or friction characteristics, and a bounded external disturbance. Computer simulations and experiments on an X-Y table verify the effectiveness of the proposed scheme.