Integral sliding mode compensator for load pressure control of die-cushion cylinder drive

This paper discusses problems of the load pressure control of electro-hydraulic drives in a presence of unknown disturbances and parametrical uncertainties. In many applications, the standard, linear control methods do not assure a satisfactory dynamical behavior and are likely to fail if a working point or the system properties change drastically. In order to guarantee a desired robustness and precision of the closed-loop system, a combination of the input-output linearization technique with the integral sliding mode is proposed. The structure of the presented controller is very simple, and can be easily implemented in standard industrial PLC's. The commissioning and tuning of the controller are uncomplicated and the adjustment procedure is partially automated. Conducted tests confirm a very good and robust performance of the closed loop control. The results are compared with those obtained with conventional linear controllers (P and PI). (C) 2011 Elsevier Ltd. All rights reserved.