Robust Backstepping Control with Active Damping Strategy for Separating-Metering Electro-Hydraulic System

Abstract

Electro-hydraulic servo systems are widely used in industrial applications. The load greatly affects the dynamic response of the separating-metering electro-hydraulic system. The current researches mainly aim at the system tracking performance for the hydraulic servo system, but the researches on the damping characteristics are relatively less. For energy-saving reasons, the metering-out chamber is often maintained near a lower pressure. The system will oscillate when the load drastically changes. The active damping strategy is proposed in this work in order to increase the damping and suppress the oscillation in separating-metering electro-hydraulic system. The effectiveness of the active damping strategy is proven by mathematical derivation. Furthermore, the nonlinear mathematical model of the separating-metering electro-hydraulic system is built, and a robust backstepping controller that combines the tracking differentiator and nonlinear disturbance observer is designed. The experimental results indicate that the system oscillation is suppressed and the proposed controller has good tracking accuracy.