Hybrid adaptive compensation control scheme for high-precision servo system

Abstract

In this paper, a hybrid adaptive compensation control scheme is proposed to compensate the friction occurrence and other nonlinear disturbance factors that exist in the high-precision servo system. An adaptive compensation controller with a dual-observer structure is designed, while the LuGre dynamic friction model with non-uniform parametric uncertainties characterizes the friction torque. Considering the influence of the periodic disturbance torque and parametric uncertainties, fuzzy systems and a robust term are employed. In this way, the whole system can be treated as a simple linear model after being compensated, then the proportional-derivative (PD) control law is applied to enhancing the control performance. On the basis of Lyapunov stability theory, the global stability and the asymptotic convergence of the tracking error are proved. Numerical simulations demonstrate that the proposed scheme has potentials to restrain the impact of disturbance and improving the tracking performance.