Implementation and Simulation of an Automated PLC Hydraulic System for a Double-acting Actuator Using a Proportional Valve

The use of electro-hydraulic valves, particularly the proportional valve, has been important progress in the development of modern automated manufacturing equipment such as cutting or forming machine tools. Using these valves, electrical control signals can be converted into fluid energy in hydraulic systems. The main purpose of this study was to implement a control system for a 4-3 proportional hydraulic valve to control the position and speed of a double-acting cylinder. In this paper firstly the equipment is introduced and then the results of the implementation of the closed-loop control of this hydraulic valve controlled by PLC have been presented. The purpose of the control system is to equalize the extending and retraction times of the double-acting hydraulic cylinder. The practical results showed the electro-hydraulic system has performed well and the system has achieved the control goal to an acceptable level. In the simulation section, the performance of an open-loop control electro-hydraulic system for tracking a harmonic voltage input signal has been investigated. The electro-hydraulic circuit was designed in such a way that the stroke time of the hydraulic cylinder is independent of the external load. The results showed that applying input harmonic voltage between -10 and 10 volts causes the cylinder rod to move back and forth under external load.