Design Of Distributed Drive Control System For Wheel-side Rear Drive Electric Bus

Compared with passenger cars,electric bus have the characteristics of large mass and large volume,so they are more prone to instability and traffic accidents.Therefore,more and more attention has been paid to the research of bus stability control system.The distributed electric bus have natural advantages because of its rapid motor response and flexible control for the stability control of the vehicle.In this paper,in order to improve the lateral stability control of distributed drive electric bus,we present a new idea and scheme.After analyzing the driving stability of the vehicle,it is found that the instability of the vehicle mainly occurs in the steering process.When the vehicle is turning,the force generated by the interaction between the tire and the ground makes the cornering characteristics of the tire in the nonlinear range,the vehicle may lose stability.For the lateral stability of vehicles,yaw rate and sideslip angle are two very important parameters.To accurately obtain the desired yaw rate and sideslip angle when designing the control strategy,a two-degree-of-freedom vehicle model is introduced.In order to analyze the motion state of the distributed rear-drive electric bus,the longitudinal motion of the vehicle and the rolling of the two driving wheels are added,and the vehicle model with five degrees of freedom is designed.Based on direct yaw moment control principle,the yaw rate and the sideslip angle are taken as the control parameters,a driving force control allocation strategy with adaptive yaw moment is designed.Fuzzy control algorithm and adaptive fuzzy control algorithm are used respectively,and the deviation between the ideal value and the actual value of yaw rate and sideslip angle of the center of mass is taken as the input of fuzzy controller,and the output is the expected yaw moment.Combined with the total driving torque made by acceleration pedal signal,the driving force is distributed according to the different steering state to ensure the stability of the vehicle.In order to verify the designed distributed driving control algorithm,a control strategy model based on Matlab/Simlink and a whole electric bus model based on Truck Sim were built,and a joint simulation platform was established.According to the actual running condition of electric bus,five typical operating conditions are designed to simulate and analyze the designed control strategy.The simulation results show that the vehicle has fast steering response at low speed.The control strategy can reduce the lateral acceleration of the vehicle effectively and follow the expected value of yaw rate and sideslip angle of the center of mass better when driving at medium and high speed and when the steering angle changes greatly.On the basis of software simulation,the hardware-in-loop(HIL)test environment is built with the industrial control cabinet equipped with NIPXIe-8880 real-time processor and NIPXI-8512 CAN communication board and the vehicle controller,and the real-time,feasibility and control effect of the designed distributed drive control algorithm are further verified.Hardware-in-loop test results show that the designed distributed drive control algorithm runs well in the processor,has obvious control effect on stable driving,and the test results are highly consistent with the simulation results.