Research On Composite Braking Control Strategy Of In-wheel Driven Electric Vehicle

With the increasingly serious problems of environmental pollution and resources shortage,the electric vehicle with advantages of energy saving and environmental protection ushers in new opportunities.The electric vehicle can convert the kinetic energy of a vehicle into electrical energy,realizing the regenerative use of braking energy,which is of great significance to the development of electric vehicles.According to the characteristics of in-wheel driven electric vehicles,the ABS control algorithm and composite braking control strategy of in-wheel driven electric vehicles are studied.Through the rational allocation of the composite braking force,the full recovery of braking energy can be achieved in the premise of ensuring braking efficiency and braking stability.Firstly,aiming at the characteristics of composite braking system,the overall control scheme of the composite braking system is constructed,and according to the needs of the composite braking system,the vehicle longitudinal dynamics model,tire model,brake pedal model,motor model,battery model and EMB system model are established.The validity of EMB system is verified by simulation.Secondly,in order to achieve the best braking performance,the automobile ABS control algorithm based on variable universe fuzzy is studied.The algorithm takes the optimum slip rate as the control target.To solve this problem,the optimal slip rate estimation scheme is proposed and its chattering elimination control is carried out.The ABS control system of automobile is designed by using double fuzzy controllers.The main controller is used to realize the tracking control of the optimal slip ratio and the auxiliary controller is used to adjust the front and rear contraction-expansion factors of the main controller in real time.The simulation results show that the automobile ABS control algorithm based on variable universe fuzzy can improve the vehicle braking performance and meet the design requirements of anti-lock brake system.Finally,in order to ensure that the vehicle can recycle the braking energy as much as possible under the braking stability,the composite braking control strategy is designed.The control strategy consists of two aspects: one is the distribution control of composite braking force,the other is the integrated control of composite braking and ABS.Different braking conditions are selected for simulation verification.The simulation results show that the control strategy has good braking energy recovery performance under the premise of ensuring vehicle braking stability.