Sensor Fault-tolerant Control For Gearshift Engaging Process Of Electric-Drive Mechanical Transmission

With the rapid development of electrical vehicles,clutchless electrical-drive mechanical transmission(EMT)without synchronizers is becoming a popular research focus of automotive industry.EMT has high efficiency,low cost and compact structure.Compared with traditional automated manual transmission(AMT),EMT also has potential of shortening power interruption time and reducing shift impact simultanouly.Currently,related research work has focused on the principles of the engagement process between gear and sleeve during gearshifting as well as the control method of active synchronization.However,the research of gearshift actuator itself especially the abnormal movement of gear-shift actuator due to sensor faults,which probably results in serious consequences,is not common.In order to improve the reliability of gearshift actuator,this thesis focues on the sensor fault-tolerant control method for gesrshift engaging process of EMT.To simulate the operating characteristics of EMT system,a detailed simulation model of EMT system is built based on professional simulation software.The dynamic model of drive motor and non-synchronizer mechanical transmission are built with LMS AMESim,while the gearshift motor,gearshift actuator controller and transmission control unit model are simulated in Matlab/Simulink.The co-simulation between AMESim and Matlab/Simulink is achieved to verify the proposed sensor fault-tolerant control method for gearshift engaging process.The hardware of gearshift actuator controller for a 4-speed EMT is designed,which can be ustilized to drive two brushless direct current motor(BLDC)independently.The hardware csn support both sensored and sensorless control method of BLDC.Therefore,the proposed sensor fault-tolerant control method can be verified in this controller.What’s more,a compact driver-in-the-loop EMT gearshift test bench is developed,which is convenient for gearshift test of EMT.Disadvantage of typical sensorless control method of BLDC with open loop start is analyzed,which makes it unapplicable for sensorless control of gearshift actuator.A novel rotor posisiton estimation method is proposed based on gearshift load force identification.A sensor fault-tolerant control algorithm against different sensor fault type is designed based on proposed rotor posisiton estimation method and typical sensorless control method.This algorithm realized closed-loop control of gearshift motor in the whole speed range,which improve s the reliability of gearshift engaging process significantly.An algorithm for active synchronization using model predictive control(MPC)is also realized in this thesis.Both mentioned algorithms are verified using the co-simulation model of LMS AMESim and Matlab/Simulink.The simulation results have shown that the active synchronization algorithm using MPC can achieve fast speed and angular position synchronization and the sensor fault-tolerant control algorithm can guarantee normal gearshift engagement of EMT even the sensor fault occurs.The reliability of non-sychronizer EMT is improved effectively.