Sliding mode control for electro-hydraulic servo system

Abstract EN

This paper deals with the problem of designing a robust controller for the electro-hydraulic position servo system (EHPSS).

The sliding mode control design methodology is utilized here to design a robust controller with respect to system parameters uncertainty.

Because the relative degree of the mechanical sub-system with respect to hydraulic force ?? is two, the switching function is constructed in two stages in order to reduce the relative degree to one.

As a result of the proposed controller, the switching function reaches the zero level in a finite time, after that the state tracks the reference value asymptotically.

The simulations result using MATLAB/ Simulink tools reveal the effectiveness and the robustness of the proposed control in forcing the position to track the reference value in spite of the uncertainty in system parameters.

The uncertainty in hydraulic system model depends mainly on the variation on load mass (20 ?? to 250 ??).

Namely, the robustness is tested for two load masses 75 ?? and 200 ??.