Design And Simulation Analysis Of Handling Stability Control Strategy For Electric Vehicles

Because of the advantages in the aspect of energy conservation and emissions reduction,electric vehicles is considered to be the best way to solve the current social energy and environmental crisis problem.Now more and more electric vehicles are put on the market,compared with the traditional fuel vehicle,the simpler driving system,provides the stability controlling of electric vehicles more diverse ways,which becomes a research hotspot in recent years.In this paper,a pure electric vehicle with rear wheel drive is taken as the research object.The research contents are mainly divided into four aspects:the establishment of the vehicle model,the design of the road adhesion coefficient recognition model,the design of the differential braking control strategy,and the effectiveness simulation verification of the control strategy.The content is as follows.CarSim and MATLAB/Simulink software were used to build the vehicle model according to the actual parameters of the research vehicle,and the simulation results were compared with the vehicle test results through the joint simulation under the serpentine test conditions to verify the effectiveness of the vehicle model.The road adhesion coefficient has a great influence on the effectiveness of vehicle handling stability control.This paper,based on the Adaptive Network-based Fuzzy Inference System(ANFIS),builds a road adhesion coefficient recognition model according to the characteristics of the curve of vehicle model's adhesion coefficient-tire slip rate on six typical roads,and compares the recognition results with data samples through joint simulation to verify the effectiveness of the recognition model.This paper analyzes the reasons of instability of vehicles,and through which choosing the stability of the vehicle state parameter.On this basis,the upper control strategy(yaw moment calculation)is designed,based on the controlling theory of PID and Fuzzy,with two degrees vehicle model to achieve the expected value of yaw velocity and side slip angle,then design PID coordinated control strategy and Fuzzy PID joint coordination with considering the tire-road friction coefficient control strategy.The control strategies make the parameters of vehicle motion change with the expected values,through which calculating additional yaw moment to maintain vehicle stability.The relationship between yaw velocity and vehicle steering characteristics is analyzed,and the differential braking control logic is determined.On this basis,the lower controlling strategy(braking moment distribution)is designed.With the analyzes of the relationship between differential braking moment and additional yaw moment,the differential braking moment distribution was realized,through which improving the control stability of the vehicle.Under the Serpentine and DLC simulation conditions,the effectiveness of differential braking control strategy is verified.The results show that this differential braking control strategy can improve the handling stability of vehicles,and the control strategy of fuzzy PID joint coordination with considering the tire-road friction coefficient,has a better adaptive capacity and control effect for low road adhesion coefficient.