Design and Implementation of PLC-Based Closed-Loop Control Strategy for Hydraulic Systems

Abstract

This paper addresses the issues of insufficient control accuracy and decreased stability in hydraulic systems, where fluctuating loads and nonlinear characteristics often compromise positioning precision in high-speed industrial applications. As modern intelligent manufacturing increasingly depends on electromagnetic sensing and reliable industrial signal transmission, robust closed-loop control architectures are essential for ensuring stable real-time operation. A PLC-based closed-loop control strategy is therefore designed and implemented. First, a hardware control platform is constructed by integrating a programmable logic controller (PLC) with sensors for real-time monitoring of oil pressure, flow rate, and displacement signals. A digital PID control algorithm is then developed, with parameter tuning and optimization performed using a hydraulic system model, followed by implementation of the closed-loop logic through PLC programming and system debugging. Experimental results show that the proposed system achieves a steady-state error of 0.15 mm, an overshoot of 4.55%, and a settling time of 0.518 s under step response testing. Under a 500 N step load disturbance, the maximum dynamic deviation remains below 0.72 mm and the recovery time does not exceed 0.45 s. These results demonstrate that the PLC-based strategy significantly improves control precision, dynamic response, and disturbance rejection capability, providing an effective solution for high-reliability hydraulic actuation while offering valuable references for electromagnetic sensing-assisted industrial automation and intelligent motion control.