Coordinated Control Based On Pump And Valve System Of Hydraulic Generators On Running Vehicle

Vehicle hydraulic generator has the advantages of small size and large power and low noise, widely used in the field of military, industrial and agriculture. Traditional vehicle transmission scheme of hydraulic power system consists of valve control motor system and pump control motor system. The valve control motor system is fast in response but low in transmission efficiency, while the pump control motor system has high transmission efficiency but slow response. According to the advantages of two kinds of control mode, the pump-valve-motor coordinated control system was set as transmission system of vehicle hydraulic generator. This control mode can realize the goal of rapid adjustment and efficient transmission when the input speed and load fluctuate. The working principle, mathematical model and control strategy were researched. The conclusion was verified under the simulation and experiment of speed control system.The structure and working principle of pump-valve-motor coordinated control system were analyzed and the system structure of variable displacement pump, proportional valve and motor were selected. The hydraulic transimission system was design. The mathematical model of parallel connection pump-valve-controlled system was established based on transfer function analytical method. The vehicle hydraulic generator system model was built under NEDC driving conditions, based on AMESim. The basic performance was simulated and the feasible of this scheme was verified.The control strategy of the pump-valve-controlled system was proposed, in this paper, which consists of feedforward PID control and segment-PID control. The variable pump was controlled by feedforward step and the valve was control by PID step in the strategy of feedforward plus PID control, in order to contol output motor speed. The system working processes were set as different work mode in the strategy of segment-PID control. The valve was controlled through multiple sets of PID parameters. The two kinds of control method were simulated respectively and the control effect was compared. The method of segment-PID was selected as the experiment method after comprehensive analysis.According to existing experimental conditions the similarity experiment plan of the coordinated control system was determined. The hydraulic drive system test bench was set up. The experiment of vehicle hydraulic generator drive system was researched. The results show that the output speed of hydraulic generators can meet the demand of Military Ⅱ standard under the segment-PID control.