Research On Adaptive Sliding Mode Control Of Wet DCT Clutch Hydraulic System

In recent years,with the rapid development of economy and improvement of automobile automatic transmission technology,dual clutch transmission(DCT)becomes a hot research issue in the field of automotive transmission with the advantages of excellent power output performance and unique structure.The clutch hydraulic control system,which has strong nonlinear characteristics,large load disturbance of the clutch and time-varying parameters,is not only the core of wet DCT control,but also the control difficulty.In this thesis,considering wet DCT clutch hydraulic system as the object,and the clutch pressure controller is designed.The following aspects are mainly studied.(1)The demand analysis of DCT clutch hydraulic control system is carried out.According to the requirements of dual clutch automatic transmission system,the main structure and working principle of DCT clutch hydraulic control system are analyzed,and the control requirements of wet DCT clutch hydraulic control system are studied during the process of launch and gear shift.(2)Clutch hydraulic control system model is established.Based on the analysis of working process of clutch hydraulic system,mathematical model of the system is deduced,furthermore,the system simulation model is set up and verified in MATLAB/Simulink environment.(3)Clutch pressure adaptive sliding mode controller is designed.With respect to the high order features of the mathematical model,sliding mode control law is designed by adopting the idea of the step-by-step sliding mode control,and the adaptive law is introduced to adjust the sliding mode control parameters,and the system stability analysis is carried out,which realizes effective control of DCT clutch pressure.(4)In MATLAB/Simulink environment,the simulation of clutch hydraulic adaptive sliding mode control system is carried out during the process of launch and gear shift of vehicle,respectively.Compared with the PID control simulation,the simulation results show that the proposed algorithm has better convergence speed,robust performance and control precision.