Fractional Order Modeling for Hydraulic Cylinder System Controlled by Electro-Hydraulic Proportional Valve

The position control of hydraulic cylinder is the key to hydro forming. However, modeling is the prerequisite for system control. In this paper, the modeling for hydraulic system controlled by electro-hydraulic proportional valve is studied. First, by analyzing the mechanism of the system, an integer-order model is derived. Then, based on the measured data obtained from the test platform, a fractional order model of the hydraulic cylinder system controlled by electro-hydraulic proportional valve is identified by using the hybrid functions based collocation method. Experimental results and associated comparisons demonstrate that the fractional order model constructed by using the hybrid functions based identification method is more accurate for describing the hydraulic cylinder system controlled by electro-hydraulic proportional valve.