Abstract: Aiming at the problem of double motor synchronization error in the hoisting process of hydraulic lifting system of heavy crane, the double motor synchronization control strategy was investigated to ensure operation safety. The dynamic characteristics of the main components of the lifting system were analyzed to determine the control parameters. And the update strategy of particle swarm optimization algorithm was improved by introducing the method of storage vector to solve the problem of "too premature". After that, the improved particle swarm optimization algorithm was used to optimize the parameters of fuzzy PID controller. It was helpful to solve the problem that PID parameters could not be adjusted online. Based on the cross-coupling control, the proposed control strategy was applied to the lifting process of crane double motors for improving the accuracy of synchronous control. In following, the simulation and experiments were carried out with the hook inclination and motor outlet pressure as the control indexes. The results show that the improved particle swarm fuzzy PID control strategy can effectively control the synchronization accuracy of dual motors and have strong anti-interference ability. Comparing with other algorithms, the control accuracy was improved by about 60%.This study can not only put forward a new method to improve the accuracy of dual motor synchronous control, but also provide a theoretical reference for the design of crane control system.

Key words: heavy crane;hydraulic lifting system;improved particle swarm optimization(PSO) algorithm; fuzzy PID; control strategy; dual motor synchronization control