Control And Simulation About Driving System Of Hydrostatic Transmission Vehicle Based On AMESim

Hydrostatic transmission system can be in a wide range of vehicle speed to realize stepless speed control, and with a small volume and weight to transfer large power, low operating cost, therefore it has been widely used in the vehicle driving systems. But this hydrostatic transmission system is a typical nonlinear, time varying high order system. Vehicles complex working conditions, and big load changes, made the dynamic performance of system change with load changes, and the changes of the dynamic performance also made the power transmission system efficiency reducing, had a gas-guzzling. So it desperately needs to adopt the advanced control technology to improve system performance.This thesis summarized the development of research on the driving system of hydrostatic transmission vehicles in recent years. Detailed analysis had been done for the hydrostatic driving system structure and principle, the speed control system of the variable pump and quantitative motor, pump discharge control agencies, engine performance evaluation indexes, and power match between engine and the variable pump and other related problems.Focuses on closed loop speed adjust system of the pump controlling motor, the hydraulic dynamic simulation model was set up based on the AMESim simulation software. And then simulation analysis had been done for the influence factors of the system dynamic performance. Analysis showed that it should design a appropriate control strategy, so as to improve the dynamic performance of the speed system.Firstly, this thesis used conventional PID controller to have speed control in AMESim. The results showed that PID only used fixed parameters to control, and had certain limitations. Using this control separately cannot fundamentally resolve the conflict between dynamic quality and stable precision. Therefore, the control system was introduced the fuzzy control method to solve the problems existing in the PID control. Using the wheels motor speed error and error rate as the input of fuzzy controller, the current controlling variation of the variable pump swashplate angle as output, the controller was designed in MATLAB/simulink. With the model in the AMESim they had a joint simulation. Results showed that the fuzzy control had stronger robustness than PID control, and also illustrated that the fuzzy control system designed in this thesis had good control effect, also had a certain theoretical significance and practical application value.This research contents provide a basis for adopting new simulation software AMESim in hydrostatic transmission system, and provide a reference of designing of the control strategy for the speed control system of pump controlling motor.