Research On Shift Integrated Control Technology For Automated Manual Transmission In Pure Electric Bus

With energy depletion and environmental pollution problems increasingly serious,countries around the world are actively seeking to develop new energy vehicles of lowemission and high efficiency. Pure electric bus is considered as one of the most importantmethods to solve the problems above mentioned and extensively concerned by public.Pure electric bus adopted the form of powertrain using driving motor+multi-speedautomated manual transmission (AMT). By the variety of gears, not only the dynamicperformance and fuel economy of the vehicles are effectively improved, but also therequirement for the driving motor and the power battery can be lower, which play thesuperiority of pure electric bus better.Combined with the key scientific and technological project of Jilin Province―Thedevelopment of the pure electric bus AMT system‖, this paper take the pure electric bus asthe platform and take the self-developed four speed AMT without clutch and synchronizeras the studying object. This paper focuses on several key problems of the shiftingintegrated control technology such as shifting process control strategy based on motoractive synchronization and integrated shifting schedule. Several aspects are researched asfollows:1) Theoretical analysis and simulation studies of pure electric bus powertrain system.Driving dynamic of pure electric bus is analyzed and simulation platform of pure electricbus powertrain is established. At the same time, its driving performance is simulated.2) Research on shifting control strategy based on motor active synchronization. Thispaper analyzes work status and control theory of the drive motor and AMT in shiftingprocess and proposes the evaluation index of the shifting quality. The meshing process ofdog clutch shifting mechanism is studied, and the factors of the shifting quality aredescribed. The optimal shifting speed range of each gear is obtained through simulation,and shifting process control strategy based on motor active synchronization is developed.3) Research on driving motor control strategy. Stator flux observer is designed andinduction motor direct torque control strategy based on sliding mode variable structure is developed. This paper studies the switching algorithm of driving motor operating modeand develops the control strategy of motor torque idling and torque recovery in theshifting process.4) Research on shift actuator control algorithm. According to PID control algorithmand fuzzy control theory, shift actuator control algorithm is developed based on the fuzzyself-adaptive and double-loop PID control. On this basis, AMT gear position self-learningsystem is designed to solve the clamping stagnation problem which is caused by gearposition changes due to processing，assembly and abrasion. So the shifting quality ofAMT system is improved.5) Research on integrated shift schedule of pure electric bus. Identification method ofthe driver’s intention based on double hidden Markov model and the estimation method ofVehicle mass and slope based on two-stage nonlinear observer is designed. According tothe identification results, shift schedule of pure electric bus is modified and integratedshifting schedule of pure electric bus based on driving intention and self-adaptive drivingenvironment is developed.6) Pure electric bus powertrain test bench is set up to verify the control performanceof driving motor speed and closed-loop torque, control performance of AMT shift actuatorand shifting process control logic. Through road test, the shifting control strategy based onmotor active synchronization and the integrated shifting schedule of pure electric busbased on driving intention and self-adaptive driving environment are verified. As well asthe improvement effect of shift quality, power and economy are analyzed.