In this paper, controller performance of three kinds of robust control systems which are Disturbance Observer, Sliding Mode Control (SMC) and H_∞ control are evaluated, when they are applied to positioning control of electrical hydraulic servo system.
We propose several evaluation methods and standard of design considering characteristic of electrical hydraulic system, and decide system parameters for each robust control systems according to the several standard of design. Next, we apply them to actual electrical hydraulic servo system, and evaluate the difference of control performance from the point of view of robustness for parameter variations, characteristic of disturbance cancellation and control input. As a result, all of them has shown good robustness, but H_∞ control shows worse performance in characteristic of disturbance cancellation and control input than other control systems.