Study On Performance Matching Of The Whole Vehicle Power System And Steering Control Strategy

Pure electric vehicle(EV)is a zero emission vehicle without pollution.How to choose and match the power system of EV directly affects its economy,power performance and driving mileage.Energy management and control system,one of the key technologies of EV,is also a key factor affecting the power and economic performance of EV.In addition,multi-axle articulated buses are increasingly appearing in the bus ranks because of their excellent passenger capacity.However,due to their special structure,the vehicle body has high requirements for steering trafficability and is liable to lead to urban traffic congestion.At present,the application of pure electric technology in articulated urban buses is relatively rare,and the related research is not in-depth,which makes the combination of pure electric vehicles.The research of pure electric articulated bus based on vehicle energy control strategy and optimization technology of articulated vehicle steering performance is particularly urgent.In this paper,a pure electric articulated bus is taken as the research object,aiming at the power matching process of pure electric articulated bus which is not yet popular at present,firstly,considering the actual operation conditions of the bus to complete the layout of the whole vehicle power system;secondly,according to the design parameters of the whole vehicle and the design index of power economy,based on the relevant theoretical knowledge of vehicle longitudinal dynamics,the pure electric vehicle is designed.The driving motors,power batteries and transmission speed ratio of articulated buses are calculated and selected,and the matching results of pure electric articulated buses are obtained.Finally,on the platform of AVL Cruise simulation software,the whole vehicle simulation model is established,includingbattery,motor,tire and transmission system models.According to the relevant regulations and the actual operating conditions of the vehicle,simulation tasks are set up to calculate and analyze the dynamic economy of the whole vehicle model,such as 0-40km/h acceleration time.The simulation results show that the parameters meet the requirements of the dynamic economy of the whole vehicle.The feasibility and rationality of the model are verified.Based on the theoretical analysis of braking stability of articulated buses,considering the conditions of ground adhesion and the position of mass center,this paper establishes the braking transient mathematical model of articulated buses,and analyses the causes of inconsistent braking of articulated buses,the hazards caused by inconsistent braking,and the theoretical solutions.On this basis,a set of braking transient mathematical models for articulated buses is designed,which is suitable for pure electric hinges.Fuzzy control based braking energy recovery strategy for receiving vehicles.The developed fuzzy controller takes SOC value of battery charging state,vehicle speed V and brake pedal opening and closing degree s as input variables,and obtains the proportion K of regenerative braking force as output variable after fuzzification,fuzzy reasoning and deblurring.Finally,the control strategy model is built in MATLAB/Simulink environment and embedded in Cruise.The simulation results show that the proposed strategy can effectively improve the braking energy recovery rate of pure electric articulated bus on the premise of guaranteeing the dynamic performance of the whole vehicle.Aiming at the poor trafficability of target articulated bus,the steering characteristics are analyzed by graphic method,and an optimization scheme of steering control strategy based on tire trajectory following is proposed.The control strategy model is built by using MATLAB/Simulink software again.The model embedded in the ADAMS software is simulated jointly,and the results are obvious.It shows that the trajectory of pure electric articulated bus tyres can be effectively followed.The trajectory error of the front and rear axles of the optimized articulated bus steering can be reduced by 72%,and the effective turning radius of the targetvehicle can be obviously reduced.