The Studies On Static & Dynamic Theory Modeling, Simulation Of Full Hydraulic Power Steering System

Full Hydraulic Power Steering System (FHPSS) carries out steering control through hydraulic system, which has been extensively applied in low-middle speeded, heavy loaded and large engineering vehicles due to its special superiority. FHPSS consists of hydraulic pump, initiative valve, steering control unit, steering cylinder and so on. In this thesis, the system includes the valve, the unit and the cylinder is studied.The theory model of FHPSS is studied in this thesis because of the shortages and problems of present static & dynamic model, which is the key part in analyzing the character of FHPSS.Firstly, the working principle of FHPSS and the relationship among those components are analyzed. The static model for each component respectively is set up and then the static model of system is set up according to the principle and the relationship, the model of steering control unit is the core part of the system. Flow characteristic curve, flow-pressure characteristic curve of steering control unit and load-speed characteristic curve, null region of system are given through analyzing the static model.Power bond graph is used to set up dynamic mathematic model at the view of energy flow because the limitation of traditional method. It can be known that FHPSS is nonlinear system from analyzing the working principle and the model of steering control unit. The dynamic mathematic models for each component are set up and the dynamic mathematic model of FHPSS is composed accord to the energy exchanging relationship of each part. The software SIMULINK of MATLAB is used to simulate the system on the base of dynamic model. The flow and pressure changing circumstances of system are analyzed on the condition of same load, different pressure & different load, same pressure and the working state of FHPSS are analyzed on the condition of different load, same steering angle & same load, different steering angle...