Study On Motor Fault Tolerance Control Method Of Wheels Drive Vehicle

Modern automobile technology develops rapidly,but the problem of resource shortage and environmental pollution becomes more and more serious.Four-wheel independent drive wheel hub motor drive vehicle,has become a global automotive industry research and development focus.However,if a device fails in the control process,it will cause the corresponding hub motor to lose power,which will not provide the expected torque and endanger the safety of the vehicle.,therefore,need to motor malfunction,the car status is restricted,fault fault tolerant control of driving motor,so as to meet the demand of drivers' driving,braking and steering,the maximum to the protection of the security and stability of the car.This article first considers the car and the lateral,longitudinal and horizontal pendulum movement and the rotation of the four wheels,respectively,the kinetic analysis was carried out on the vehicle and the wheel,the vehicle dynamics model is established,the wheel dynamics model and the tire model,and based on high precision dynamic software ve DYNA simulation verification,to prove the reliability of the model accuracy.Secondly,based on the previously established seven-degree-of-freedom model,the fault tolerance control system of the automobile motor driven by wheel hub based on torque distribution is designed.In the case of single motor failure,the fault tolerance control method and the structure of the controller are given.Considering the complexity of the car body dynamics model and the simplicity of the tire model,the layered control structure is adopted.The upper controller USES the nonlinear model predictive control algorithm to control the body dynamics,and outputs the longitudinal slippage of four wheels to the lower controller.The lower controller USES PID algorithm to control the roll rate of four wheels.Considering the influence of different speeds and failure wheels on the vehicle driving condition,different situations were simulated and verified respectively based on MATLAB/Simulink software.The simulation results show that the proposed fault-tolerant control algorithm can effectively improve the vehicle tracking effect for the desired speed and roll rate.Finally,for vehicle models with active steering system,a fault tolerance controller based on wheel hub drive based on torque distribution and active steering is designed.A new fault-tolerant control model and control method are also presented for single motor failure.The steering Angle is constrained in the upper controller,and the steering Angle is output to the vehicle model while output the roll rate of four wheels to the lower controller.Based on the MATLAB/Simulink software simulation results show that the improved algorithm of fault-tolerant control can not only ensure the vehicle tracking to the desired state,also can carry on the control of steering Angle,front wheel active steering.