Research On Longitudinal Dynamic Control Of In-wheel Motor Electric Vehicle

With the increasingly prominent energy and environmental issues,new energy vehicles have attracted more and more attention,and China has also listed new energy vehicles as one of the seven strategic emerging industries.As an important member of new energy vehicles,the in-wheel motor electric vehicle is directly driven by the in-wheel motor installed in the hub,which has many advantages,such as low mechanical loss,fast power response,independent drive by wire and so on.In this paper,four-wheel independently driven in-wheel motor electric vehicles as the research object,and mainly studies to achieve the goal of improving the economy and stability of the whole vehicle through the reasonable distribution of driving torque under the premise of ensuring the vehicle dynamics.The details are as follows:(1)A joint simulation platform is built based on Matlab / Simulink and CarSim software.The whole vehicle dynamic model of the in-wheel motor electric vehicle is established by using CarSim software,and the in-wheel motor model,the vector control strategy of the in-wheel motor and the driver intention recognition model are established by using Matlab / Simulink software,which are used for the simulation verification of the subsequent control strategy.(2)Pavement condition recognition based on convolutional neural network.Based on the convolution neural network,pavement condition recognition is designed.Through the effective recognition of the road image,the corresponding road adhesion coefficient is obtained,which is used for the optimal control of driving torque.On this basis,Burckhardt tire model is used to identify the optimal slip ratio under different road conditions,which can be used for the anti-skid control of the driving wheel of the in-wheel motor electric vehicle.(3)Design of driving torque control strategy for in-wheel motor electric vehicles.The energy consumption of in-wheel motor is analyzed,and different control strategies are designed according to the driving state of the vehicle.Under normal working conditions,considering energy saving and load transfer,multi-objective coordinated control of driving torque is adopted to improve the power and economy of the vehicle.Under the emergency condition,the anti-skid control of the driving wheel is carried out to solve the problem of excessive sliding of the driving wheel and improve the driving stability of the whole vehicle.(4)Simulation test and verification of the drive torque control of the in-wheel motor electric vehicle.Based on the Matlab / Simulink and CarSim joint simulation platform,the drive torque optimization control strategy is tested and verified through the NEDC cycle conditions,and the effectiveness of the control strategy is verified using the wheel hub motor efficiency operating point and the vehicle energy consumption index.Accelerating driving conditions on two typical roads with high adhesion dry asphalt pavement and low adhesion ice pavement were designed,and the drive wheel anti-skid control strategy was tested and verified.The results show that the designed control strategy can effectively restrain the wheel slip.