Driving Force Distribution Control Methods Of Four Independent Electric Cars And Vehicle Ride Comfort Analysis

Vehicle emissions and pollution become worsen, because haze and other issues are around us. Automotive energy power system is turning complicated and electrical,and electric cars replace the traditional vehicles, in the condition that the technology of new energy vehicles has been focused on development and research, which has become a new target for the automotive vehicle industry.Compared with the traditional cars, electric car system has many advantages, for example improving vehicle dynamics control for energy and safety performance significantly. Traditional vehicle engine control is based on its dynamic mechanical characteristics of engine and aerodynamic. Its reaction time is about a lot of milliseconds. But to electric vehicle not only the torque response speed up, but also electrification execution unit control accurately, what is more the control period and dynamic response are fast, as fast as several milliseconds. So that the performance of the vehicle dynamics control, for example, longitudinal torque control has been greatly improved. Now the motor productive technology has a great progress, for example power density and reliability are improved, we can directly control torque with the method of vector. Traditional four-wheel drive car needs a complex mechanical system, whose transmission efficiency is not satisfied and each torque for single wheel can’t be controlled separately. Wheel motor can be driven independently for every wheel. The use of the decentralized controller, precise controller technology and torque distribution strategies for each wheel torque greatly enhance vehicle total control performance and coordination ability. So we can control the yawing moment,tire anti-lock braking ability and acceleration slip regulation.In order to research four-wheel independent drive electric cars, a reasonable allocation of each wheel longitudinal force is founded to improve vehicle ride performance. The driven strategy is based on the equal torque output as target. Using the optimal control theory to design the feedback system of controller, we can control the currents of four motors. With the help of ADAMS and Simulink, we accomplishthe joint simulation and the dynamic response of the drive system model is established. In the case of standard test, there are three schemes to be tested. At last,we use MATLAB to calculate the vehicle ride performance and it is proved that the method can improve its ride comfort.