Research On The Calibration Method For Gear Shifting Of High-Power Automatic Transmission

As the core of shift operation, shift quality control is one of the most critical technologiesof the High-Power Automatic Transmission control. Calibration is the process of adjustingand optimizing the electronic control system software to determine the calibration parameters,based on different performance requirements, in order to improve the adaptability of a varietyof conditions, and therefore, calibration is the key step to implement control strategy andoptimize control quality.The electro-hydraulic shift control system of a certain tracked vehicle automatictransmission was taken as research object. Theoretical and test research of the principlecharacteristic of this digital electro-hydraulic shift control system are conducted fully,in-depth theoretical study on its control characteristics. The shifting process control strategy isdetermined, and the influencing factors of shift quality are confirmed through theoreticalanalysis, especially the open loop control phase. A new calibration method and calibrationprocess is put forward, and the calibration software is designed to realize the automaticcalibration process base on the unique mechanical properties and control features.A mathematical model of proportional electromagnetic valve coil current is establishedbases on the analysis of its working principle, and making a scrutiny into control features ofthe proportional solenoid valve by the reasonable experiment method design. According tothe analysis of the test data determine the compensation method. Through comparisonbetween test results before and after compensation based on the embedded control system,which could conclude that the compensation control method has a certain rationality andreliability.With the supports of dynamic analysis of the shift process apply equivalent lever method,the shift qulity control process can be divided into four phases: open-loop control phase,torque phase, inertia phase and high-grade phase. The ideal clutches engaging/releasingstrategies in the open-loop control phase were proposed and the reasonable calibration methodwas proposed to eliminate the influences of the changing oil temperature and the enginerotation speed. A hardware-in-the-loop simulation platform for joint simulation test validationstudies is built based on TruckSim and MATLAB/Simulink software, to verify the correctnessof the proposed calibration method and calibration software reliability.Real vehicle calibration experimental studies, which for a wheeled vehicles equipped with the integrated transmission, are carried on under different conditions and in different oiltemperature, and the bench shift quality verification test is proceed with the correction of thecalibration data for the control system, which further proved that the designed calibrationmethod effectively reduces the open loop control phase shift shock while the transmissioncontrol unit has very strong robustness and adaptive ability towards system characteristicvariation and environment disturb.