ROTAIONAL SPEED CONTROL OF A HYDRAULIC SERVOMOTOR WITH A LARGE INERTIA LOAD USING SLIDING MODE CONTROL

Abstract

Rotational speed control of a hydraulic motor with a large inertia load has issues on stability and sometimes falls into unstable. In this paper, the discrete-time sliding mode control (SMC) is applied to rotational speed control of a hydraulic motor for improving its robustness. Modeling of the control components and design of the sliding surface (switching line) in the state space are discussed. Furthermore, one of the means attenuating chattering due to the SMC is presented. The control characteristics is evaluated by a testing apparatus which consists of the hydraulic motor of 28cm³/rev coupled to the large inertia load of 0.88kg·m². The results of a theoretical and experimental study of the SMC show several benefits such as shorter settling time, lower sensitivity to disturbances and system parameter variations.