Study On Control Method Of Automated Manual Transmission Oriented Shifting Process In Pure Electric Bus

Owing to its features of high transmission efficiency and operability, the AutomatedManual Transmission (AMT) is widely used in the domestic city electric bus. However, theAMT for city electric bus, which often works under low speed and frequent shifting drivingconditions, has not only the problem of big shifting impact caused by the big change rate ofdrive torque in the shifting process, but also the problem of low electric efficiency. Therefore,this paper takes a three-gear AMT of a certain type of electric bus in Guangzhou city as theresearch object and studies the control method of the electric bus AMT oriented shiftingprocess for the purpose of shifting comfort.The paper first introduces the research status at home and abroad of the electric bus AMT.Then it studies the AMT control principle of the electric bus, and according to the automobiletheory and working principle of the synchronizer, this paper establishes the mathematicalmodel of five-stage shifting process: before shifting, disengage synchronizer, choice gear,engage synchronizer and finish shifting. On this basis, this paper analyzes the reason of bigshifting impact in the shifting process of AMT in the electric bus from the perspective of thecontrol method, and verifies the analysis result through the real vehicle experiment.Afterwards, for the purpose of comfortable shifting process, the electric bus AMT controlmethod, aiming to reduce the impact during shifting, is proposed in the paper. Then, in orderto minimize the drive motor power consumption, this paper proposes the design method ofAMT transmission ratio optimization based on dynamic shift point. As a guide, the electricbus AMT control system is designed, and the electric bus AMT shift control simulation modelis established by using Matlab/Simulink simulation software to verify the feasibility of theAMT shift control process. Comparison and analyses are presented between the AMT shiftcontrol simulation results and the real vehicle experiment results so as to verify thecorrectness of the AMT shift control simulation results. At the same time, the electric busAMT control method oriented shifting process and the original car control methods are alsocompared and analyzed. At last, based on the electric bus AMT control system, the AMTexperimental platform is established, and the shift control experiment of the electric bus AMT oriented shift process is carried out.