Self-tuning-parameter fuzzy PID temperature control in a large hydraulic system

Oil temperature control in a large hydraulic system is dealt with using the fuzzy logic control algorithm. Mathematic model of the control system characterized by large time delay is created based on law of thermodynamics. A self-tuning-parameter fuzzy PID controller is designed to regulate the cooling water flow rate through the triple proportional valve in order to control the oil temperature. The simulations and experiments are carried out, making a comparison with conventional PID control. The results suggest that fuzzy PID strategy can efficiently improve the performance of the hydraulic temperature control system, irrespective of time delay problem and parameter variations. It achieves higher control accuracy of temperature, faster response and stronger robustness than conventional PID control system.