Research On Speed Synchronous Control Of Drive System Of Distributed Electric Vehicle

Distributed electric vehicle has received extensive attention due to the high transmission efficiency and independent controllability of the driving force and braking force of each driving wheel.The drive system of a distributed drive electric vehicle consists of two or more motors.If the multiple motors are not properly coordinated control during driving,the driving wheels will drag or slip each other,which will cause the electric vehicle to deviate from the target trajectory,and even cause traffic security incident in severe cases.Therefore,this paper takes distributed drive electrics as the research object,and proposes a four-wheel distributed drive system(FWDDS)speed synchronous control strategy,from the two levels of synchronous control structure and control algorithm to realize the coordinated of each wheel’s speed.The main research includes:Firstly,a new approaching law(NRL)that can take into account both high approaching speed and low buffeting level is designed based on the exponential reaching law,and its stability is analyzed.At the same time,an extended state disturbance observer based on the hyperbolic tangent function is designed to estimate the internal and external disturbances of the controlled object.The estimated disturbance value is fed forward to the sliding mode controller based on the new reaching law for disturbance compensation,thereby forming an anti-disturbance compound control(ADCC)algorithm,which can enhance the anti-disturbance ability and the robustness of the drive motor control system.The ADCC algorithm and NRL provide theoretical basis for the design of speed tracking controller and synchronization error compensator respectively.Secondly,the generalized mean deviation coupling structure(GMDCS)is proposed to realize the speed synchronous control of FWDDS under straight and curved driving conditions.The GMDCS introduces the proportional synchronization coefficient and system generalized mean speed on the basis of the traditional deviation coupling structure.This structure has a simple compensation mechanism and can realize proportional synchronous control.The FWDDS speed synchronous control system is designed based on the GMDCS,in which the speed tracking controller and synchronization error compensator are designed based on ADCC and NRL respectively.And the stability of the FWDDS speed synchronous control system is verified by the Lyapunov function.Finally,a permanent magnet synchronous motor(PMSM)speed control experiment platform based on Speedgoat real-time target machine and a FWDDS speed synchronous control co-simulation platform based on Simulink and Carsim were built.The experimental results show that the NRL has the characteristics of simultaneously taking into account high approaching speed and low buffeting level,and the PMSM control system under the ADCC algorithm has stronger anti-disturbance ability and better speed tracking performance.Based on the co-simulation platform,the control performance of the three control strategies is compared and analyzed under straight driving conditions and curved driving conditions.According to the simulation results,the GMDCS combined with the speed tracking controller based on the ADCC algorithm and the synchronization error compensator based on the NRL can greatly improve the tracking performance and synchronization performance of the FWDDS,so that the vehicle can track better the target trajectory.