A new hydraulic drawing system of coal mining machine is proposed in this paper. The variable plunger pump adopted in the hydraulic drawing system of coal mining machine is replaced by load-sensing variable displacement pump. The working principle and energy-saving of the new system are introduced. The performance of the new system is obtained by the simulation study using AMESim.

This paper analyzed the reasons of motor speed loss under variable load in variable-speed pump-control-motor governing system, and pointed out that oil compressibility caused by load change is one of the reasons. Speed drop compensation coefficients ware derived, and the compensation method under variable load in variable-speed pump-control-motor governing system was built. The simulation results show that the compensation method can well compensate motor speed loss in variable load.

This paper analyses the reasons of motor speed loss on variable-speed pump-control-motor governing system, and points out that the reasons are system leakage, electromotor characteristics and oil compressibility caused by system pressure change. Speed loss compensation method of variable-speed pump-control-motor governing system is put forward. Simulation analysis is carried out under constant load, variable load and variable-speed, and simulation results show that the compensation method can well compensate motor speed loss.

An integrated hydraulic speed control platform including fuzzy self-tuning PID controller is developed using LabVIEW. The pump-control-motor variable speed throttle combined speed governing experimental system is tested under the different speed governing control model. Experimental results show that, the complex speed control can be regulated to maintain a desired response and the fuzzy control technology enables better control characteristics.

The variable speed hydraulic systems have many advantages, and research about this field in recent years has developed rapidly. In this paper, a variable speed hydraulic system is studied using BP Neural Network PID controller. The research results show that using BP Neural Network PID controller can achieve good control effect.