Research On Fault Tolerant Control Of Vehicle Stability System Actuator

Vehicle driving safety has always been a key research issue in the automotive field.With the development of science and technology,automotive active safety technology has continuously achieved new research results,from fully manual driving,to the addition of various assisted driving systems,and to the realization of autonomous driving,which shows that the application of automotive active safety technology to the development of automotive more and more important.Vehicle stability control is an important achievement in the development of automotive active safety technology and provides a very important guarantee for the safe operation of vehicles.The electronic stability control system(ESC),as an active safety system for vehicle assembly,has significantly improved the stability of the vehicle's operation,effectively guaranteed the driving safety of the vehicle,and can prevent the vehicle from oversteer,understeer,rollover,and slip Waiting for a driving accident has largely avoided casualties.An actuator fault of the vehicle stability control system can cause sudden changes in wheel and tire forces,thereby limiting the vehicle's executable drive space.Vehicle speed and front wheel angle are also limited to a certain range due to actuator fault,so the vehicle loses driving stability and driving safety.This paper proposes a fault-tolerant control method for actuator fault that can reduce the impact of fault.Fault-tolerant control enables the vehicle to safely maintain its original trajectory with reduced performance.This article is the study of active fault-tolerant control,and the fault information of the vehicle stability system is known information.This paper establishes a sevendegree-of-freedom model of the vehicle and introduces actuator failure.The faulttolerant control in this paper is mainly divided into two parts: fault-tolerant control I is a quadratic programming optimization algorithm with constraints;fault-tolerant control ? is to reconstruct the upper-level controller and weaken the control target.This paper establishes a seven-degree-of-freedom vehicle model that includes the effects of actuator faults in vehicle stability systems,and this paper adopts the hierarchical design concept to design the fault-tolerant control method.First,in the upper-layer control,the vehicle's longitudinal speed deviation,lateral speed deviation,and yaw speed deviation are used as input quantities.The optimal control of multiple inputs and multiple outputs is used to design the upper-level stability controller,so that the actual state of the vehicle can be tracked.The reference value of the state quantity,and obtain the longitudinal resultant force,lateral resultant force and yaw moment to ensure the stable operation of the vehicle.Secondly,in the lower layer control,firstly,based on the principle of the friction circle of the tire,the effective range of the tire force is obtained,and the influence of the actuator failure is introduced to obtain the feasible region of the fault tolerance control of the tire force.Based on the feasible region of fault-tolerant control of tire force,the feasible region of fault-tolerant control of vehicle 's resultant forces and resultant moments are derived through derivation.Aiming at the situation that the tire force,the resultant forces and resultant moments caused by the actuator fault exceed its fault tolerance feasible region,the optimal tire force distribution results through a quadratic programming algorithm with fault constraints,so that the allocation result meets the feasible region of fault-tolerant control.Then,when there is no feasible solution for the above quadratic programming algorithm,the method of weakening the input of the control system is adopted first,that is,the weakening coefficient is introduced to reduce the vehicle speed and the front wheel turning angle;At the same time,the method of reconstructing the upper controller is adopted,that is,the reconstruction coefficient is introduced to adjust the output of the upper controller;and then the resultant force and the resultant torque of the upper-layer controller are reasonably distributed to the faulty wheels and normal wheels through the above-mentioned secondary planning algorithm to achieve fault-tolerant control.Finally,the simulation experiment of fault-tolerant control of vehicle stability system actuator fault was carried out by building a system model in Matlab/Simulink.The experimental results verified the effectiveness of the proposed fault-tolerant control method to solve the vehicle stability system actuator fault problems.