The Research And Optimization On Ride Performance And Handling Stability Of Electric Vehicle

With the PM 2.5 into the public eyes, environmental and energy issues once again have aroused people's reflection upon the development of industry. The development of the thermal power industry has to be reassessed. It is believed that the car is one of the leading causes of air pollution and it is urgent to find a clean power for cars. Electric vehicle is a representative of clean energy and get people's favor. Especially in recent years, the development of electric vehicle and related industries has shown unprecedented prosperity under the joint efforts of the state and enterprises. In this paper, the following issues are studied in detail and in-depth based on a certain type of electric vehicle:Firstly, the dynamics model of the front and rear double wishbone independent suspension are established according to the hard point coordinates of the suspension. At the same time, the dynamic model of steering system, front and rear tires, body and driving system are established,and then the whole vehicle dynamics model is obtained through assemblage.Secondly, the parallel wheel suspension simulation based on the front suspension model is carried out to test the suspension performance. The results are obtained as follows: In static equilibrium position, toe angle is 0.13° , camber angle is 0.23° , caster angle is 5.38°,the kingpin inclination angle is 10.02 ° and the suspension stifness is 21.58 N/mm. The performance of the suspension is reasonable and basically meets the design requirements.Then, the ride performance simulation test of random input and pulse input are carried out,In the simulation process, the maximum RMS of seat is 0.1314m/s2, the maximum vertical acceleration of the body centroid is about 9.493ni/s2, Therefore, the ride comfort of the model meets the requirements. In this paper, the influence ofunsprung mass increased on vehicle ride performance is discussed. The results show that the increase of unsprung mass has no significant effect on the results of random input test. But for the pulse input test, the vertical acceleration is increased with the raises of the vehicle speed and the unsprung mass, and the amount increases with the raise of vehicle speed .In the aspect of handling stability analysis,fish hook test, step steer test, impulse steer test and cornering with steer release test and so on are conducted. The stability is basically reasonable, but with the increase of vehicle speed stability is significantly worse.Finally, this paper accomplishes the optimization of suspension and vehicle performance.First of all, the sensitivity analysis of the front suspension is carried out, and the main factors affecting the performance of the suspension are determined. Then, the full factorial design of 7 factors and 3 levels is used to optimize the wheel alignment parameters, and the variation range is significantly reduced. The orthogonal test is used to optimize the performance of the vehicle.The optimization results show that the response time of the yaw rate and lateral acceleration are shortened, and the maximum value of vertical acceleration is reduced from 4.398n/s2 to 3.611m/s2, the ride performance and handling stability of the vehicle are improved, which has certain practical value.