The Application Of Low Order Model Reference Adaptive Controller In Hydraulic Force Control System

In the hydraulic-servo system we studied in this paper, we make the force output of hydraulic cylinder as the feedback signal. As we know the hydraulic-servo system have it own intrinsic property, such as the varying of parameters, external load disturbance and has no accuracy model. Because adaptive control can effectively erase the effect of model error, barrage jamming and inhibit varying of parameters. So in order to obtain perfect controlled result, we use model reference adaptive control theory to control the hydraulic-servo system in this paper.Structure of adaptive controller in this paper is output error model reference adaptive control theory. First constitute a low-order adaptive controller (assuming that the object as a third-order systems) to control the actual higher-order systems. Although the existence of the system model error, but the adaptive control system itself is a model of eliminating errors in nature and So the low-controller to control the Third Order of the actual hydraulic systems, simplifying the control algorithm, enhanced adaptive control performance.The simulation study find MRAC in hydraulic-servo system with the traditional control methods : in parameters time-invariant systems, MRAC system has no obvious advantages; in parameters time-varying systems and outside perturbing, MRAC system has better track and control precision; when there are drastic changes in the parameters, or a strong outside perturbing, MRAC system itself is unstable. Experimental results show that when parameters are time-varying, This output error model reference adaptive control methods can effectively control the hydraulic force control systems.