Motion synchronization control of four multi-stage cylinders electro-hydraulic elevating system

In order to achieve synchronization lifting of heavy load and long stroke, four-cylinder synchronous lifting system was used through a proportional flow control valve controlled multi-stage cylinder. A mathematical model of a proportional flow control valve controlled multi-stage cylinder was established and dynamic analysis of the mathematical model was carried out. Based on dynamic analysis, control strategy has been adopted as that open-loop control mode is used in the proportional flow control valve controlled multi-cylinder and expert PID compensation strategy is used between four multi-stage cylinders. Experiment research of four-cylinder synchronous lifting system was performed. Experiment results show that synchronization error is less than 30mm in the whole lifting process when lifting load is 30t and cylinder stroke is 2.55m. Synchronization precision can meet the application requirements. Experiment results prove the feasibility and validity of the open-loop control mode and expert PID compensation strategy.