Design And Analysis Of Electromagnetic,Regenerative And Friction Composite Brake For In-wheel Motor

At present,most of the brake systems of passenger cars use disc friction brake systems to realize the function of slowing down and stopping the car.However,disc brake systems have problems such as slow braking response,brake disc wear and thermal degradation.In order to improve the shortcomings of disc brakes,non-contact electromagnetic braking technology and motor regenerative braking technology have attracted people’s attention.The integration of that electromagnetic braking system,regenerative braking system and friction braking system can play its own advantages,which can improve the response speed of the composite brake system and improve the safety of vehicle braking.Firstly,this paper designs a structure of electromagnetic,regenerative and friction composite braking system,then calculate the power of the hub motor required for the motor of the electromagnetic,regenerative and friction composite braking system according to the vehicle dynamic requirements.According to the electromagnetic braking torque and other requirements,the iron core diameter,the number of coil turns and other parameters in the electromagnetic brake are calculated.Through carrying on the simulation in Maxwell,the result shows: the designed electromagnetic brake satisfies the design demand.Secondly,through the establishment of vehicle model and composite braking system models in MATLAB,based on this model,pure electromagnetic braking,pure regenerative braking,pure friction braking,electromagnetic and friction composite braking,regenerative and friction composite braking,electromagnetic and regenerative compound braking and electromagnetic,regenerative and friction compound braking conditions are simulated and analyzed to obtain the braking performance of each braking mode of the compound braking system.Then,the designed composite brake system was processed into a prototype,and various brake modes were tested on the in-wheel motor electric vehicle electromagnetic,regenerative and friction composite brake test bench.The test results show that the various braking modes of the composite braking system of in-wheel motor electric vehicles can be used to brake the vehicle as required,and when the composite braking mode is adopted,it can effectively improve the braking torque response time,which can effectively improve braking safety.Finally,based on the hybrid control theory,a switching control strategy for the compound brake system is proposed.A corresponding control algorithm is given to distribute the braking torque for each braking mode.At the same time,in order to obtain better braking comfort,a torque feedback controller is designed to reduce braking torque fluctuations.The simulation results show that the compound brake system can work in different modes to brake according to the coordinated switching control strategy,which verifies the feasibility of the control strategy.