Fault-tolerant Control Of The Distribution Of Driving Force In Four-wheel Independent Drive Electric Vehicles

At present,as people pay more and more attention to the environment and the demand for clean energy,the characteristics of new energy electric vehicles such as zero pollution emission and low energy consumption are in line with the general trend of green and clean energy utilization,and the demand for electric vehicles as vehicles is also increasing in the world.For four wheel drive(4WD)distributed electric vehicle(EV),its anti-slip fault-tolerant control is characterized by multiple actuators,strong coupling,nonlinearity and uncertainty,which makes each subsystem interact and restrict each other.Therefore,in order to improve the fault tolerance and robustness of the system and reduce the computational complexity of the system,an adaptive sliding mode fault tolerance control method based on multi-agent system(MAS)is proposed in this paper.In this paper,four wheel drive hub electric vehicle as the research object,combined with the knowledge of multiple agents,the electric steam drive anti-skid system(ASR)and actuator fault-tolerant control technology is studied.Firstly,this paper analyzes the anti-skid working principle of distributed driven electric vehicles.Based on the multi-agent theory,the four-wheel independent drive ASR system is decomposed into four-wheel intelligent agent system,which reduces the model dimension compared with the traditional complex model.Therefore,the design of ASR system controller is transformed into the design of single-wheel intelligent agent controller.According to the connection structure and internal working communication principle of electric vehicle,the topology structure composed of four wheel agents and the virtual leader introduced to obtain the optimal slip rate is obtained.According to the system disturbance with known upper bound,a single wheel intelligent terminal sliding mode controller is designed,which makes use of the advantage of precise torque control and torque distribution control strategy to make the actual slip rate track the ideal slip rate in finite time,and proves the system's Lyapunov stability.Secondly,in order to enable the vehicle to still run well on different roads under the action of ASR system,the proposed driving force distribution control strategy is more universally applicable.In order to solve the chattering caused by the overestimation of the gain,the gain of the sliding mode controller is selected by the adaptive estimation mechanism of the single wheel intelligent agent.Therefore,for ASR system,adaptive estimation mechanism is used to select the gain of sliding mode controller to solve the problem of gain overestimation.The control rate is redesigned and the liapunov stability of the system is proved.The control strategy guarantees the smoothness of the actual control signal,reduces chattering and improves the robustness of the system.Compared with the previous control method,the convergence time of the control system is shortened,the dynamic performance of the slip rate tracking control is improved,and the reliability of the control strategy is improved.Then,on the basis of the study of driving anti-slip control with unknown disturbance upper limit,the single-wheel intelligent agent controller based on multi-agent theory was designed according to the fault severity of partial failure(PLOE)and deviation fault severity of the needle actuator fault,so as to improve the fault tolerance of ASR system.Finally,carsim-matlab /Simulink was used to build a joint simulation platform for the control of driving slip rate of electric vehicles,and a simulation experiment was carried out on the working condition of wet cobblestone and dry cement docking pavement.Simulation results show that the control strategies proposed in this paper can achieve good tracking control effect of slip rate in a limited time,and achieve the purpose of driving anti-slip(ASR)system.The adaptive sliding mode control method is adopted to estimate the switching gain,which effectively reduces chattering and energy loss,and makes the driving force distribution strategy more universal.The adaptive sliding-mode fault-tolerant control method based on multi-agent system(MAS)can effectively reduce the actuator fault impact and realize the tracking control of slip rate,which improves the safety and passability of vehicles.