Study On Characteristics Of Vehicle Hydraulic Power Steering Gear And Its Test System Development

The Steering system of automobile is an important part for the driving system. The rack and pinion power steering gear of rotary valve has been widely used in the car. Based on this kind of steering gear, its structure, performance analysis, modeling method and how to build an accurate, high efficient, stable test-bed applied the modern testing technology and method were studied in this dissertation. The main contents of this dissertation are as follows:The development of the power steering system, its testing technology and its dynamics simulation methods was introduced in Chapter 1 at first. Then the importance of the combination of the testing technology with simulation methods based on theory modeling in order to analyze the performance of the power steering gear better was aroused.The structure, assist principle and some parameters of the steering gear were analyzed in Chapter 2. The mathematic model of the hydraulic steering system was established. The dynamic performance of the system was given by simulation with MATLAB.The influence of the system parameters such as pressure, flow, piston area A and the load parameters such as load mass, load stiffness to the system dynamic performance was researched.The performance evaluations such as steering sensitivity and steering feel and their analysis of the hydraulic power steering system were put forward in Chapter 3. Investigated the effects of several factors such as gear ratio and steering sensitivity on the assist characteristic by MATLAB/SIMULINK.The design and realization of the power steering system test-bed was set up in Chapter 4. Contrasting the experimental method with aboard method, the experimental method of this test-bed was confirmed. The structure, principle, three key technologies and software of the test-bed was analyzed and realized to satisfy the experiment requirement. Then test data of the test-bed and the simulation result were analyzed. The data can prove the reliability of the test-bed and the accuracy of the theoretical analysis.In the end, the dissertation was summarized in the last chapter, and the possible research in future is presented.