Dynamic Modeling And Analyse For Shifting Process Of Automatic Transmission

With the continuous development of China's economy,cars are gradually entering into homes.Because of its stable starting,convenient operation,good ride comfort,energy saving,environmental protection,safety and reliability,the automatic transmission vehicle has many advantages.It is the direction of future vehicle development.Automatic transmission is the most important core part of vehicle automatic transmission.The separation clutch and combination clutch have great influence on the shift quality of the vehicle.For vehicles equipped with hydraulic mechanical automatic transmission,there are a large number of unknown and nonlinear factors in the transmission of power from the engine to the whole vehicle.In addition,the dynamic characteristics of the fluid involved in the power transmission have brought difficulties to the system control of the automatic transmission,especially the adaptive control of the combined clutch in the shift process.This paper combines the Institute of electro-hydraulic servo simulation and test system of Harbin Institute of Technology and the Guizhou kai Xing hydraulic mechanical transmission Company on the cooperation project of "the development of high power hydraulic automatic transmission".Study the shift mechanism of high power hydraulic mechanical automatic transmission.First,modeling the power transmission route of the vehicle equipped with the Guizhou Kai Xing 3000 series hydraulic mechanical automatic transmission.Engine inertia model,torque converter model,planetary gear transmission mechanism model and vehicle load model are established respectively.Taking the optimal power shift of the whole vehicle as the goal,solve the shifting schedule of the Guizhou Kaixing 3000 series hydraulic mechanical automatic transmission,and discuss the influence of the driving environment on the shifting schedule.Set up the simulation platform of vehicle power transmission system.The speed curve of the torque converter is simulated when the first gear is up to two gears.The model is verified by real car experiment.Establish the shift clutch hydraulic control system model of Guizhou Kai Xing 3000 series hydraulic automatic transmission,and simulating the model by using Matlab/Simulink software.When the duty ratio of the shift solenoid valve is decreased from the maximum to a certain value,analyze the oil pressure fluctuation of the inlet port of the clutch cylinder.Determine the optimal duty cycle reduction method.Analyzed the kinematics and dynamics of internal planet gear transmission mechanism of Guizhou Kai Xing 3000 series hydrodynamic automatic transmission.The clutch to clutch shift process is divided into four stages.Establish the relationship between the angular acceleration of the turbine axis,the acceleration of the output axis of the transmission and the torque of the input shaft of the transmission,the torque transmitted by the brake and the output shaft torque of the transmission under the "torque phase" and "inertial phase".Taking vehicle's dynamic performance and comfort performance as the evaluation index,building shift control unit model,Improving and optimizing the control parameters of gear shifting process,the shifting performance is improved while the shifting comfort is ensured.