The Use of a Model-Based Controller for Dynamics Improvement of the Hydraulic Drive with Proportional Valve and Synchronous Motor

Abstract

Electrohydraulic drives consist of several nonlinear elements, and the use and design of their control system is difficult. One of the most important parameters of the industrial drive is its settling time, which characterizes their dynamics. An interesting control method, which can be used for the improvement of electrohydraulic drive properties, is the model-following control (MFC). This technique enables to ensure the good control parameters of nonlinear systems in quite an easy way. In this paper, a modification consisting of changing the oil flow factor in the reference model is proposed. This improves both the dynamics of the electrohydraulic servo drive and the adaptation to the load forces, and thus energy consumption. The article describes the application of the MFC method to control an electrohydraulic servo drive in which a special proportional valve, with an permanent magnet synchronous motor (PMSM), is used. To verify the effectiveness of this method, a theoretical description of the drive is proposed. The applied MFC control system is then modeled and investigated in simulations. Lastly, laboratory investigations are made and chosen results are presented and described in the paper. The results obtained in simulation are compared with results obtained in laboratory tests. The investigations show that the usage of MFC shortens the drive settling time and, in this way, improves its dynamics.