A robust adaptive control strategy for electro-hydraulic servo based on friction compensation

Abstract

The electro-hydraulic servo system has the advantages of high stiffness, fast response speed, high precision and power-to-weight ratio. In this patent, an adaptive robust control strategy based on friction compensation is proposed for insufficient control accuracy due to a large number of nonlinearities and uncertainties in the system. In this patent, the mathematical relationship between the physical quantities of the valve-controlled cylinder is analyzed. Then the mathematical model of valve controlled cylinder considering the main nonlinearity and uncertainty of the system is established. The fuzzy proportion-integral-derivative, deterministic robust, and adaptive robust single-cylinder trajectory tracking controllers are designed and the tracking performance of different reference trajectories is analyzed by MATLAB/Simulink software. In this patent, all the three controllers can track the reference trajectories smoothly. Adaptive robust control strategy can make the uncertain parameters of system converge and approach truth value. In this patent, the adaptive robust control strategy has the function of online parameter adjustment. When tracking accuracy is taken as the index, its tracking effect is better than fuzzy proportion-integral-derivative and deterministic robust.