Research On Torque Control Strategy Of Front And Rear Wheel Independent Drive Type Electric Vehicles

In the face of contradictions between automotive development needs and environmental issues,in order to promote the sustainable development of the automotive industry,the energy-efficient and pollution-free pure electric vehicle has become an effective way.Compared with other forms of electric vehicles,the front-and-rear-wheel-independent-drive-type electric vehicle(FRID EV)takes into account the advantages of traditional centralized driving EV and hub-motor-in-wheels driving EV.It has been a research hotspot in recent years and the key research direction of future vehicle technology.This paper takes FRID EV as the research object,and focuses on the single-motor drive and dual-motor drive mode selection problem,and the sudden change of the vehicle torque when switching between different drive modes,resulting in vehicle power output stability problem.The research work has certain engineering and academic significance for improving the economic performance of FRID EV and improving the torque control strategy of EV.Based on AMESim software,the vehicle dynamics model,driver model,wheel and tire model,motor model and power battery model are established.The vehicle control strategy model is established by Matlab/Simulink.The joint simulation model of the FRID EV is established through the joint simulation interface.And using the experimental data to test and verify the established simulation model.Combined with the working characteristics of the FRID EV,the total loss power of the front and rear motors is minimized as the optimization target,an optimal torque distribution strategy with energy saving as the goal is proposed.By controlling the torque distribution coefficient,the selection and switching between the single and dual motor drive modes are made.And the torque distribution of the front and rear motors is dynamically adjusted in consideration of the situation of the drive wheel slip.Based on the optimization of the torque optimization distribution strategy to determine the single and dual motor drive modes,a torque dynamic coordination algorithm based on comfort is proposed.Taking the minimum longitudinal jerk in the mode switching as the target functional,the optimal control function of the jerk in the mode switching process is obtained according to the optimal control theory.And use this as a basis to control the front and rear motor torque during mode switching.Using the NI-PXI real-time simulation system and the RapidECU controller,a hardware-in-the-loop(HIL)test platform for the FRID EV controller is established.Through the HIL test,the proposed torque control strategy is used to improve the economy and the effectiveness of acceleration slip regulation.