Research On Dynamic Characteristics Of Electro-Hydraulic Proportional Valve-Controlled Cylinder System Based On Fuzzy PID Control

With the development of hydraulic technology and computer control theory,electrohydraulic proportional control technology is widely used in many marine devices such as marine cargo lifting platforms.When the electro-hydraulic proportional valve controlled cylinder system operates under frequent load changes,it is affected by hydraulic cylinder leakage and the dead zone of the proportional valve in the system,resulting in crawling phenomenon during low-speed movement,greatly affecting the control accuracy of the system and limiting the promotion and application of the electro-hydraulic proportional valve controlled cylinder system in the shipbuilding industry.Therefore,how to reasonably compensate the neutral dead zone of the proportional valve and the leakage of the oil cylinder of the electro-hydraulic proportional valve control cylinder system to ensure that the synchronization error of the two cylinders is within a controllable range is the key to the normal operation of the marine cargo hydraulic lifting platform.This paper takes a ship cargo hydraulic lifting platform as the research object,and uses the method of combining simulation analysis and test verification to deeply study the influence of the electro-hydraulic proportional valve control cylinder system on the dynamic performance of the system due to the dead zone of the proportional valve and the leakage of the oil cylinder.First,based on the mathematical model of each part of the electro-hydraulic proportional valve-controlled cylinder system,the overall transfer function of the system considering the leakage of the hydraulic cylinder is derived,and the system stability is analyzed.Secondly,aiming at the dead zone of the proportional valve and the leakage of the cylinder in the electro-hydraulic proportional valve control cylinder system,based on the traditional PID control theory,a fuzzy PID controller suitable for the system was revised and optimized.Thirdly,the simulation model of the synchronous valve is optimized through the simulation software,and the joint simulation model of the electro-hydraulic proportional valve control cylinder system is established to ensure that the simulation analysis is closer to the actual working state of the system.Under different flow rates,different pressures,and different control strategies,the influence of leakage on the dynamic characteristics of the system was simulated and analyzed.Based on the analysis results of the system’s single hydraulic cylinder leakage compensation,the dual hydraulic cylinder synchronous control compensation strategy was studied.Finally,based on theoretical analysis,simulation research and test verification,the response curve of the electro-hydraulic proportional valve control cylinder system based on the optimized fuzzy PID control is obtained,which verifies the feasibility of the system compensation algorithm.The results show that the optimized synchronous valve combined with the optimized fuzzy PID controller can significantly improve the response speed of the electro-hydraulic proportional valve control cylinder system,and the dynamic characteristics of the system are also more ideal,which solves the problem of large synchronous errors in the dualcylinder synchronous system.Simulation analysis was conducted under different flow rates and pressures,and an optimized fuzzy PID controller was used to reduce the dual cylinder error of the synchronous control system by 11% to 15%.