Composite Braking Dynamics Analysis And Control Of Electric Vehicle With In-wheel Motors

Nowadays, due to the increasing exhaustion of oil resources and environmentalprotection consciousness which have been in the limelight, the electric vehicle back intopeople’s life by its clean energy. However, the current technology of electric vehicle is stillnot mature and exist many disadvantage aspects, which particularly reflected in thelimitation on driving range. While the regenerative braking system is one of the keytechnologies to improve the signal charge range. The paper will offer a specific analysisabout the research of composite braking system of electric vehicle with in-wheel motors,put forward a corresponding control strategy, and verify whether can improve regenerativeefficiency through joint simulation models.This paper describes background of research and offers the definitely tendency ofelectric vehicles, analyzing the advantage of electric vehicle with in-wheel motors in theindustry of electric vehicles, showing the electric vehicle apply to regenerative brakingsystem is indispensable, introducing the condition research of domestic and overseas. Inaddition, this paper is subjected to the related theories of regenerative braking system,which points at the fundamental theory of regenerative braking system and applies theprocedure of vehicle brake to dynamic analysis, studying the braking force distributionsprocedure of front and rear wheels brakes in theory. Researching constraint constrains ofthe system, which presents the design principal and the function of the system. This articledescribes three typical control policies, which is the parallel, the fixed proportion and theideal braking force distribution control strategy. These control strategy should be putforward to discuss the reality methods and steps. Presents a new composite braking controlstrategy in view of the electric vehicle with in-wheel motors, owing to the reality targetvehicle and motor parameters determine the braking force distributionrelationship, including the front and rear wheel braking force distribution and allocation ofelectronic brake force, then put forward the implementation method and the concrete steps respectively. Furthermore, introducing the joint simulation software, and explain theprocess of joint simulation, using CarSim establish an electric vehicle with in-wheel motorsdynamics model, then using Simulink to establish the control strategy model and pointingout the exports and imports in model. The fundamental calculating arithmetic in this paperis PID controlling arithmetic is chosen for its simplicity, reliability and stability. Finally,start the joint simulation based on the proposed control strategy.This article treats the braking performance evaluation index as the evaluationreference of regenerative braking system. By using the joint simulation model to analyzetwo kinds of braking conditions: one is the typical braking condition, let the target vehiclebraking with a certain initial velocity at different braking intensity, such as initial velocityis30km/h,60km/h,100km/h in the braking intensity was0.05,0.1,0.3,0.5, the second isto choose UDDS,1015two typical urban driving cycles on joint simulation. The simulationresults show that the proposed control strategy can meet the requirements of vehiclebraking on the braking distance, braking time and braking stability, and can reasonable usemotor braking force according to the initial velocity and brake strength. Finally, make thetarget vehicle simulation controlled by other three typical strategies in the same cyclemodel. Compared with energy recovery effect, the results show better control strategy isproposed in this paper, we can conclude that the proposed control strategy can beeffectively used for regenerative braking.