Study On The Fuzzy-PID Theory Using In The Construction Vehicle Hydraulic Driving

Construction vehicle driving dynamics step into a new stage—hydraulic driving dynamics. The research is going to improve vehicles' adaptability under dynamic condition, optimize vehicle's performance and achieve good maneuverability. The key content is variable pump-variable motor system's structure and control theory.The paper analyses show that hydraulic driving system of construction vehicle is a nonlinear and time-varying plants which model structure is known and parameters are variety. It's linear model can't meet people's demand. Aims at complex nonlinear and variable structure factors, the paper combines constant-power control method and ideal hydraulic driving control structure, presents a modern integrate control strategy using in vehicle driving system.The paper gives a hydraulic driving system's dynamic model which engine rev is variable and motor's displacement is variable, analyses the system and brings forward a integrate control structure includes constant-power control inputting part and system main part, then introduces motor's HA control method to the system. Bases on discussing the-flow coupling system section, paper introduces Fuzzy-PID theory to system, and presents a new control structure which uses Fuzzy-PID as control. A Simulink model was built in paper and was run to prove the system's well perfonnance. Then the paper analyses the feasibility of control strategy in motor's variable displacement section. Lastly, paper analyses coupling parameters in system, and gives the rules of selecting parameters. The research method applying in paper is suit for other vehicle driving AC systems or modern control systems.