Study On The Key Problems For The Electric Driving Automatic Mechanical Transmission System

Power driveline technology is the key technology of electric driving vehicles, typesand properties of power driveline system directly determines the power performance andthe energy consumption efficiency of electric driving vehicle. In order to improve thevehicle driving wheel torque, and to meet the requirements of electric driving vehicle’sdynamic performance, the traction motor need to use together with the variabletransmission device. Electric driving automatic mechanical transmission(AMT) system inthis research, is a new type of electric driving power driveline system, which has aconsiderable apply potential. The key problems in electric driving AMT system in thisrelated research are: wear and self calibration problem, shift control strategy and the shiftride comfort of coordinated control logic. The main works of this paper include:Taking MATLAB/Simulink software for modeling and simulation platform, a forwardsimulation model and an electric driving AMT vehicle model were established forsimulation foundation and platform of the following researches of the electric driving AMTcomprehensive shift schedule and the shift ride comfort of coordinated control logic.Through the analysis of the causes of wear, introduced the elasto-plastic fractal theoryas the main research method of electric driving AMT’s wear problems. According to thedegree of influence on shifting performance, divided the AMT wear into two major types.Based on the improved Majumdar-Bhushan (M-B) fractal contact model, established thetwo kinds of wear fractal prediction mathematical model for electric driving AMT system,and simulated on them. Based on the fractal model, presented a control strategy ofautomatic calibration system for electric driving AMT. The experiments for system lifeprediction and shift parameters automatic calibration were carried out.According to different control objectives, dynamic, economic and reliable mode ofshift schedule for electric driving AMT vehicles are presented and a comprehensive shiftschedule model is established with precise traction motor torque and speed experimentaldata. The state function and objective functional are established by using dynamicprogramming and variety of optimal shift schedules are solved for different control weights.The simulation results indicate that the vehicle performance with comprehensive shiftschedule which limited on reliable constraint is better than the traditional method. Thevehicle experiment verifies the applied feasibility of this method. According to shift ride comfort for the electric driving AMT vehicles, an evaluatingalgorithm is presented based on pearson product-moment correlation coefficient&decision-making trial and evaluation laboratory. A new evaluation system is rebuilt bycalculating the importance and contribution for the original parameters. The results indicatethat the new evaluate parameters are different from the traditional AMT shift qualityparameters in evidence, and more suitable for AMT shift ride comfort evaluation of electricdriving vehicles. Through the analysis of electric driving integrated gear shifting process ofAMT, found the effect of control parameters of shift ride comfort, and decoupled the shiftprocess for power interruption, pick neutral, gear synchronous and power recovery phases.For each stage respectively established the optimal objective function, and taken optimalcontrol of shifting process. Finally a kind of step by step optimal coordinated controlstrategy for electric driving AMT system was presented.A semi physical simulation platform for AMT control system was built based ondSPACE MicroAutoBox, and shift control logic of semi physical electric driving AMTsystem was verified by the platform. Based on the developed AMT controller and electricdriving system prototype, an experimental bench was built. Taken the shift experimentalresearch on the integration of power driveline for electric driving AMT system and the shiftperformance and reliability for the AMT system were tested. In order to verify the formertheoretical researches in this paper, electric driving AMT prototype vehicle experimentswere taken for the comprehensive shift schedule and the step by step optimal coordinatedcontrol strategy.