| With the development and popularization of automatic transmission technology,people’s requirements for shifting process control of automatic transmission are no longer limited to meet the gear switch function.The demand for the quality of the shift is getting higher and higher.The shift process control t algorithm is one of the key technologies of AT control.Its quality directly affects the vehicle’s power,economy,riding comfort and the service life of components.Therefore,the research of shift process control is of practical significance.On the basis of a pre-research project "X X X X electronic controlled hydraulic automatic transmission integrated application technology",analysis of AT power up based dynamic characteristics and principle of clutch-to-clutch shift gear process in detaile,build a system simulation platform of electro-hydraulic shift control,coordinated control strategy is introduced into the engine,the control stage optimal control of shifting process principle based on the solving method and the optimal tracking control law,reduce shift shock and reduce the friction work of clutch and gear shift time.The research object of the system analysis of hydraulic control system and working principle,based on the transmission dynamics model based on Lagrang equation,gives the gear up the dynamic differential equations of different stage,according to the Flare condition and Tie-up condition of the two typical conditions,the shift process control parameters were analyzed.The clutch component is analyzed by force,and the clutch friction characteristic model is established through experiment.The dynamic friction coefficient and the static friction coefficient of the friction disc during the shifting process are given,and the relation curve between the friction coefficient and the speed difference between the clutch main and driven disk is obtained.MATLAB/simulink and LMS.AMEsim are used to build the simulation platform of the electro-hydraulic shift control system.Match engine and torque converter.A dynamic response model based on centrifugal pressure compensation is built for clutch components,which makes the model closer to the actual working effect.The state space equation of the shift process is established,and the control strategy of the torq--ue phase and the inertia phase is used to control the shift process: torque phase clutch friction torque constant slope control;inertial phase optimal tracking control,comprehensive consider of performance index functional of the jerk and the friction work,the optimal control law is solved by the principle of minimum value,and optimize the shift time,and the calculation process of shift time is given.In the shift process,the coordinated control of the engine is introduced to reduce the jerk and the friction work.The AT power-on shift control strategy is simulated on the simulation platform of power transmission system.Compared with the traditional open loop control method of clutch hydraulic pressure,the results show that the optimal control strategy can significantly reduce the jerk of the shift and the friction work of the clutch,and a real vehicle test is carried out. |
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