Analysis And Study Of The Key Parts That Influence On-center Performances

As the development of the freeway industry and the raise of the vehicle’s speed, people are paying more attention on the safety when driving the vehicle at high speed, which is more and more general. The on-center performances are key to the safety of the vehicle in high speed area. Therefore, studying the on-center performances and the key parts that influence those most are one of the important urgencies when designing the chassis at present. This paper imbeds the steering system based on Simulink into the complete vehicle model based on Carsim, which helps to confirm the influences of the tire incentive on the on-center performances. Then the key parameters of steering system and the tire incentive are conducted by the method of sensitivity analysis and the ways to improve the on-center performances are proposed. Next, the relationship between the steering test of on-center and the returnability test of high speed is studied. The details are as follows:(1) Building up the steering system model. First, converting a complicated real steering system to a relatively simple physics model. By doing force research on the key parts of the physics model, every key part’s kinematics equation is obtained, and then the steering system model is built up by Matlab-Simulink. Besides, by the foundation of traditional steering system model, this model fully considers the steering clearance、the moment of inertia of every component and valve inlet friction、 valve inlet damping、 damper ring of the steering valve. Moreover, this model studies the influences of the tire incentive on the steering gear’s dry friction.(2) Asociated simulation by Simulink and Carsim. Building up the complete vehicle model by Car Sim software, and then the Simulink steering system model is imbedded into the Car Sim vehicle model to implement the associated simulation. This paper selects some typical tests that include the on-center steering test. Then the validity of the model is validated and it proves that the influences of the tire incentive on the on-center performances do really exist.(3) Analysis of the on-center performances. This paper introduces the objective indexes of the on-center performances, and then the method of on-center experimentsis is used to do the sensitivity analysis. The tire incentive and key parameters of steering system are changed to observe the variations of those indexes to study their influences on the on-center performances. Finally, the ways to improve the on-center performances are proposed.(4) The analysis of relationship between the on-center steering test and the returnability test of high speed. This paper uses Carsim to conduct the on-enter steering test and the returnability test of high speed with six simulation vehicles. Then, the objective indexes and the related coefficients are obtained. By studying the meanings of those coefficients, this paper analyses the feasibility that using the oncenter objective indexes to describe and replace the returnability test of high speed.