Research On Traction Control For Electric Bus

Traction Control System (TCS) is of significance in motorized vehicle. It caneffectively stop wheel spinning when vehicle starts or speeds up on the road which havedifferent friction coefficient. TCS can improve dynamic performance and driving stability.Electric bus as large commercial vehicle more tend to slip on a slippery road and causetraffic accidents. Research on traction control for electric bus has important practicalsignificance. The paper proposes reasonable and effective traction control strategy andvalidates its feasibility through offline simulation and HILS. The main topic is as follows.The paper studies electric bus dynamics structure firstly and established15DOFelectric bus dynamics model which has high universality and can fully consider theperformance of vehicle. The vehicle dynamic model is divided into7sub-models in termsof the function, which includes suspension model, vehicle body model, tire dynamic model,wheel model and in-wheel motors model, steering model, velocity control model.The paper fully studied the research status on traction control of traditional vehicle,traction control of EV and road-tire friction coefficient identification and proposed tractioncontrol strategy with optimal slip ratio recognition based on fuzzy logical, whose inputvariables are slip ratio and utility friction coefficient, whose output variable is the similarityof four μ-λ standard curve. The paper could get the optimum slip rate by using fuzzycontroller. The optimal slip ratio is a weighted arithmetic mean of the output variables offuzzy controller and the optimal slip ratio of four standard road surface. Based on real-timeidentification of optimal slip ratio, the traction control strategy for electric bus is proposedin the paper, in which the control variables are wheel slip ratio and the control method isPID.In order to validate the feasibility of TCS control strategy, the paper establishes TCScontrol strategy model by use of MATLAB/Simulink software. The control strategy hasbeen simulated on the off-line simulation platform in two conditions that the vehicle startsor speed up on the middle friction coefficient road and the low friction coefficient road. The simulation results show that the proposed control strategy can prevent the wheel fromspinning effectively and improve vehicle dynamic performance and driving stability.In order to validate the practicability of TCS control strategy, the paper design thehardware in the loop simulation plan of TCS and established the platform. TCS controller isbased on MicroAutoBox hardware and electric bus dynamics system is based on Simulatorhardware. TCS controller and electric bus communicate each other via the CAN bus. Thepaper conducts the HILS test of three conditions. The consistency of HILS results andoffline simulation results indicate the accuracy of vehicle model and rationality of TCScontrol strategy.