Robust adaptive tracking control of hydraulic actuators with unmodeled dynamics

Abstract

Traditional control methods for precise motion control of electro-hydraulic servo systems are primarily based on rigid-body dynamics of the system. Considering that structural flexibility of the mechanical components have a certain impact on all drive systems, the neglected high-frequency dynamics caused by structural flexibility have become one of the major obstacles when developing better control performance. In this paper, a high-accuracy tracking control is concerned for hydraulic actuators with unmodeled flexible dynamics. Firstly, a damping term is utilized to counterweigh the unmodeled nonlinear flexible function and a dynamic signal is designed to control the dynamic flexible disturbance. Then, in order to process parametric uncertainties along with unmodeled flexible dynamics, an adaptive backstepping controller is proposed. The controller theoretically guarantees global bounded tracking performance via Lyapunov analysis. The experimental and simulation results illustrate the high-performance nature of the proposed controller.