Research On Fault-tolerant Control Of Distributed Drive Electric Vehicles

Since the beginning of the 21 st century,the environmental pollution caused by the burning of fossil fuels has become increasingly serious.The resulting air pollution,such as smog,has seriously affected human health.At the same time,with the huge consumption of fossil fuels,petroleum-based fossil energy has been depleted.Therefore,electric vehicles are more and more in people's vision in line with the development of the times,and distributed drive electric vehicles are at the forefront of electric vehicles with their unique advantages.It does not require traditional transmissions such as gearboxes and drive shafts.The structure saves more vehicle space,and thanks to the ability to independently control the four wheels,it provides richer and more direct ways for vehicle stability control.But distributed drive electric vehicles have four drive units,which increases the risk of failure and poses challenges to vehicle fault tolerance control.This article is funded by the Nanjing University of Science and Technology's international exchange and cooperation project "Research on Optimal Torque Distribution Method of Electric Vehicles Based on Nonlinear Model of Tires",and researches on distributed electric vehicle yaw stability and fault-tolerant torque distribution algorithm.The ability of the control algorithm in real-time is further studied.The main research contents of this article are as follows:First of all,for the distributed drive electric vehicles to be studied in this paper,the vehicle body dynamics modeling,suspension dynamics modeling,tire and wheel dynamics modeling are performed.The experimental results are compared with Car Sim vehicle model.Then the vehicle stability index is analyzed,and a yaw stability controller based on sliding mode is designed for the yaw stability of the vehicle,in order to adapt to the situation that some parameters of the vehicle body will continue to change under certain complicated driving conditions.Because the centroid side slip angle required by the yaw stability controller cannot be obtained by the sensor,a centroid side slip angle observer based on unscented Kalman filtering is designed.After obtaining the target yaw moment from the yaw stability controller,a torque distribution controller based on particle swarm algorithm was designed.Particle swarm optimization takes minimum tire utilization as a fitness function,takes into account the effect of tire vertical load transfer,and is restrained by longitudinal force requirements and yaw moment requirements,first ensuring that tire forces work within a reliable range,and secondly meeting Driver's need for speed response and steering.Based on the vehicle control framework,a method for active fault detection of motors based on fuzzy control is proposed,and different failure modes are analyzed.A targeted control method is proposed.Experiments show that the control response is fast and the effect is good.Finally,this study conducted a hardware-in-the-loop test based on NI PXI.The embedded C code was generated from the yaw stability controller in the Simulink model,and the particle swarm algorithm code of the torque distribution controller was handwritten.The parameters of the particle swarm algorithm were determined based on the real-time performance requirements of vehicle control.The shortcomings of conventional quadratic programming are large calculation and poor real-time performance,which finally verifies the effectiveness of the control algorithm in this paper.