Modular Design And Study On In-wheel Driven Electric Vehicle

The development of the automobile industry is facing with tremendous pressure because of the persecution of the natural environment that produced by the consumption of the earth's renewable energy as well as the rapid development of human society.In this background,many automotive companies all over the world have begun the study of environmentally friendly energy vehicles,among them,the in-wheel driven electric vehicle has great potential for development for its clean power source,environmental protection,efficient transmission power,compact and smart structure as well as better electronic control performance.But the application of in-wheel driven system still has many difficulties,such as the in-wheel drive system will be increased on the quality of the sprung mass which represents reducing the vehicle ride comfort and handling stability,and the in-wheel motor will receive pavement vibration interference from the pavement profile.In this paper,we design the structure of the active wheel of in-wheel driving system basing on the Michelin active wheel.The modular active wheel is integrated with a shock absorbing small spring to reduce the deterioration of the riding quality and comfort caused by the increased unsprung mass of the in-wheel driven electric vehicle,and the parameters of the spring in the wheel are optimized.At the same time,simulations have been made to analysis the differences between the traditional in-wheel driving system and the modular active wheel system in riding comfort and handling stability,the simulation results show that the electric vehicles with a modular active wheel can effectively improve the vehicle ride comfort and the handling stability compared to the traditional in-wheel driven electric vehicle.This article utilize the 1/4 dynamic model of in-wheel driven electric vehicle and the tire-ground contact dynamic load,dynamic deflection of vehicle suspension,and the vertical acceleration of the vehicle body are defined as the performance indexes to evaluate the vertical vibration performance of the vehicle.The amplitude and frequency response and the root mean square of the response are used to analyze the influence of the in-wheel driving vehicle on each index.The simulation results show that the in-wheel driven electric vehicle will deteriorate the ride comfort and safety of the vehicle.Based on the amplitude frequency curve of each performance index,the parameters of the spring that in the modular active wheel are optimized by using the A-Opt and P-Opt optimization strategies.The simulation results show that all the performance indexes of the vehicle have been improved significantly.Finally,this thesis analyses the ride and handling performance differences between traditional in-wheel driven electric vehicle and the modular active wheel assembly driven electric vehicle in the dynamic model of the full vehicle.