Abstract:Aimed at the requirements of high performance and high efficiency of the hydraulic ship lift, the multi degree of freedom test platform and hydraulic cylinder control systems with longstroke, combined with the high performance of the valve control circuit and the high efficiency of the pump control circuit, the valve control open circuit and pump control closed circuit were used to parallel driven the new circuit. The new circuit can acquire high performance and high efficiency, but focuses on maintaining performance. In order to improve the performance of the new circuit system in operation, such as the stability and the control precision with load, a speed and position composite control strategy with load compensation was proposed, and the load compensation calculation model and speed feedforward control calculation model were determined. The simulation results show that by using this control strategy, both speed and position can be controlled simultaneously, and better control performance can be obtained under different loads.