Study On Torque Coordinated Control Of Small Four Wheel Drive Electric Vehicle

Because of its simple structure and four-wheel independent control,the chassis integrated control has more obvious advantages and development prospects.It is considered as the ultimate form of automobile development,and has been concerned by scholars at home and abroad.But because the four wheels are independent and controllable,the torque distribution of the four wheels can be coordinated and controlled to adapt to different conditions and complex roads,so as to improve the maneuverability and stability of the vehicle.In order to improve the stability of the four wheel motor-driven electric vehicle,this paper studies the four-wheel torque coordinated control of the four wheel motor-driven electric vehicle.Based on the vehicle kinematics,aiming at the torque coordinated control of the four wheel motor-driven electric vehicle when the wheel slip occurs,the torque of the four wheel motor-driven electric vehicle when driving in a straight line is proposed Coordinate control strategy.First of all,according to the judgment of wheel slip when the vehicle drives anti-skid,the Federal Kalman filter algorithm is designed based on the multi-sensor information fusion method,and the vehicle speed is estimated according to the wheel speed signal and body acceleration signal.Then,the slip PID controller is designed according to the wheel speed and the estimated speed.According to the output torque of the slip PID controller,the slip wheel torque is adjusted and the non slip wheel torque is coordinated.When the wheel torque is coordinated,the driver’s longitudinal demand torque is considered,and the influence of the yaw moment of the four-wheel longitudinal driving force around the center of mass on the vehicle stability is also considered.According to the different situations of wheel slip,this paper analyzes the different situations of single wheel slip,multiple wheel slip and front and rear wheel slip respectively,develop the corresponding torque coordination control method,improve the stability of the vehicle,and try to maintain the dynamic performance.Then use MATLAB / Simulink and Car Sim to build a joint simulation platform,according to the various situations of wheel slip,design the corresponding road model to simulate the speed estimation algorithm and torque coordination control strategy.The simulation results show that the speed estimation algorithm has high accuracy under different wheel slip.The designed torque coordinated control strategy can meet the requirements of torque coordinated control under various wheel slip conditions,reduce wheel slip,improve vehicle stability and maintain vehicle dynamics.