Research On Distributed Driving Control System Of The Electric Bus

With the features of larger mass change,high center of gravity,significant pitch and roll moment,it has been a hot research topic on how to improve the handling stability and safety of the electric bus in both industry and academia.The distributed driving electric bus has simple chassis structure and high transmission efficiency.By independent control on driving or braking force,the variation of the load,as well as the pitch moment and roll moment can be reduced,thus improving the handling stability of the vehicle.As a result,this paper provides a method and solution for handling stability control of the distributed driving electric bus.First of all,an electric bus which is refitted by a mass production fuel vehicle is introduced.The proposed electric bus utilizes a rear-drive distributed system by employing two in-wheel motors.The longitudinal,lateral,yaw and roll moments of the vehicle are analyzed,and the sprung mass and unsprung mass of the vehicle are also defined.In this connection,an eight degrees of freedom(DOFs)vehicle mathematical model is constructed.Then,aiming at improving the handling stability,a practical control strategy which considers the adhesion utilization factor between the wheel tire and the road,is proposed for the distributed rear-drive electric bus.The fuzzy logic control theory is used in the design of the control strategy of the distributed rear-drive system.Secondly,the vehicle dynamic model,distributed rear-drive control strategy,and the co-simulation platform are realized via TruckSim and MATLAB/Simulink.By this way,numerical simulations and analysis are conducted based on the proposed distributed rear-drive control strategy,and the performances of different control strategies under various simulation environments are verified.Furthermore,this work proposes a control system for the distributed rear-drive electric bus by considering the characteristics of the real vehicle,and the overall design of the framework,and the software and hardware implementation are also achieved.As for the hardware,selection of the main parts and design of the signal processing circuit is completed.When it comes to the software,the generation for the computation layer of the control strategy is finished by using RTW module of MATLAB,and the driving layer in the lower layer of the function module is also completed under Code Warrior environment.Finally,real vehicle tests are conducted on the proposed distributed rear-drive control system of the electric bus under numbers of working conditions,and CANape are utilized for collecting and monitoring of the driving data.The test results show that the performance of the proposed distributed rear-drive control system can satisfy the requirement of the electric bus,and at the meantime,the handling stability of the vehicle can be improved during cornering process.In addition,the accuracy of the control model and effectiveness of the co-simulation are also verified.