| Automotive industry is moving towards the direction of intelligence.As one of the core components of the car,the intelligent degree of automatic transmission directly affects the driving experience and driving performance of the car.Combined with a project called ‘Research and development on two-gear AMT system for electric vehicle’,relevant research on shift control strategy has been done in this paper.First of all,the difference of shifting process between electric vehicles and conventional vehicles equipped with AMT was analyzed;then the dynamic analysis of the shifting process and the movement of the actuator were carried out.Based on SimDriveline,Stateflow and MATLAB/Simulink,the whole vehicle simulation model was established.Then in order to verify the correctness and feasibility of the model,simulation analysis was made on the acceleration shift process under the fixed accelerator pedal.This model laid the foundation of further research.Secondly,the basic shift schedule based on the opening degree of the accelerator pedal and the speed of the vehicle was established.But it has the problem of poor adaptability of different working conditions,especially in the braking condition.In order to solve this problem,the design of fuzzy recognizer were made by setting the accelerator pedal opening degree,its change rate and vehicle acceleration as input and the driver’s intent as output.According to the identification of the driving intentions,basic shift strategy was amended and the design of shift schedule with real time driver’s intentions recognition was made.Simulation results show that the shift schedule can make the corresponding shift based on the driving intentions.The condition adaptability was greatly strengthened.Again,relevant analysis and research was made to solve the shift cycle problem occurred during the simulation process when the road slope been inputted in is very large.Then based on the fading memory recursive least-squares method,the ramp online identification device was designed.According to the recognition results,the adaptive shifting law of the slope correction was designed.Simulation results show that the shift schedule can be a good solution to the problem of shift cycle.Finally,engineering modification of the simulation model and C code generation were carried out.Test bench was built and the performance of software system and hardware system of the transmission control system was tested,which laid the foundation for the on-board test.Then,the real vehicle road test was carried out,which verified the feasibility of the integrated control of the electric drive AMT power assembly. |
