Theoretical and Experimental Analysis of a Coupled System Proportional Control Valve and Hydraulic Cylinder

The aim of this paper is to analyze the driving system actuated by a proportional directional control valve on a hydraulic cylinder. In order to evaluate the dynamic interaction between the proportional valve and the cylinder theoretical analysis, numerical simulations as well as experimental test are performed. Coupling cylinder and proportional valve, it is very important to know the ratio of their natural frequencies. In particular, if the valve is characterized by a lower natural frequency, its behavior prevails so that no resonance peak can be observed on the coupled system. On the contrary, resonance phenomena can be observed in all the other cases. It is important that these phenomena are preventively taken into account to realize a precise and accurate control system of a hydraulic axle. At last, three different control methods are tested on the coupled system: Proportional Integral Derivative technique (PID), the adaptive “One-Step-Ahead” control technique, and an expert control technique and the obtained precisions are very interesting.