Adaptive Control for a Piezoelectric-Actuating Table Based on Lugre Friction Model with Functional Approximation Compensation
A long range friction actuating mechanism was designed by using piezoelectric material to generate high frequency oscillation for actuating a finger tip which contacted with a slide to induce the back and forth motion. The LuGre friction model is chosen to simulate the dynamics of this friction actuating mechanism. However, this piezoelectric actuating system has obvious nonlinear and time-varying dead-zone offset control voltage due to the static friction and preload. It is difficulty to establish an accurate dynamic model for model-based precision control design. Hence, the functional approximation (FA) scheme is employed to compensate the system modeling error. The Laypunov-like design strategy is adopted to derive the adaptive laws and the system stability criterion. The dynamic experimental results of the proposed controller are compared with that of a model-based PID controller. Keywords - Piezoelectric actuator, LuGre friction model, FA based adaptive control.