Research On Stability Control And Drive-fault Tolerance Of Multi-axle Special Vehicle With In-wheel Motors

In today’s battlefield,military multi axle special vehicles must have more and more high mobility and active safety to meet the requirements of high-performance battlefield operations.Therefore,multi axle military special vehicles with electric wheel drive technology have attracted more and more attention from all over the world,and gradually become a hot spot and important development direction in the research field.Compared with the traditional power transmission system,the electric wheel drive technology has obvious advantages in chassis layout and torque distribution.The research object of this paper is an 8 × 8 electric wheel drive special vehicle.Combined with fuzzy control and sliding mode control and other related algorithm knowledge,the yaw stability and drive fault-tolerant control technology of the research object are studied.Firstly,based on the software platform of TruckSim,the model of key parts of the whole vehicle is constructed,including the vehicle body model,suspension system model,steering system model and tire model.At the same time,the driving motor model is established by using Matlab/Simulink.Then,the dynamic model of 8 × 8 electric wheel driven special vehicle is constructed by combining the two parts of the model.Secondly,the vehicle stability is analyzed and studied.The reasons of vehicle instability are analyzed from the aspect of tire dynamic characteristics.The control parameters and control methods of vehicle yaw stability are analyzed and studied.The yaw rate and sideslip angle are selected as the control parameters in this paper.Combined with the direct yaw moment control technology,the vehicle yaw stability is ensured.In the state reference layer,the ideal vehicle steering state is derived based on the linear two degree of freedom dynamic model.In the desired torque generation layer,based on the deviation between the ideal state and the actual state,the sliding mode variable structure control algorithm is used and the adaptive variable exponential reaching rate is introduced to improve the desired torque tracking control effect.In the torque distribution layer,the optimal control idea based on quadratic programming algorithm is adopted,and the weighted least square method is used to calculate the output torque of each actuator,so as to improve the vehicle stability and mobility to the greatest extent.Then a typical vehicle driving condition is set to test the lateral stability control architecture,which verifies the effectiveness of the designed control strategy.Then,the fault-tolerant control of vehicle driving is studied.The failure modes of 8 × 8 electric wheel drive vehicle are analyzed.According to the number and location of the failure motors,the whole vehicle drive system is divided into255 failure categories.In order to facilitate the fault-tolerant management of each failure category,all the failure categories are divided into unilateral drive failure and bilateral drive failure,and then the rule-based drive fault-tolerant control strategy is formulated for these two types of failure.At the same time,the concept of motor failure factor is introduced to re describe the residual torque output capacity of the failed motor.According to the residual torque output capacity of each driving motor in the vehicle drive system,the torque distribution control based on optimization is carried out.Then the failure state of the drive motor is set on the basis of the typical steering driving conditions of the vehicle,and the designed control strategy is simulated and tested based on the failure test conditions,which verifies the effectiveness of the drive faulttolerant control strategy.