Study On Modeling,Estimation And Control Of Transmiting Torque For HEV Automatic Diaphragm Spring Clutch

Automatic Diaphragm Spring Clutch(ADSC)is one of the important assembly of modern vehicles.It has been more and more applied in Automatic Manual Transmissions(AMT),Dry Dual Clutch Transmissions(DCT),and Hybrid Electric Vehicles(HEV).In this dissertation,the research is on the transmitting torque of an ADSCwhich is specifically used on one coaxial parallel hybrid electric vehicel.The study covers the modeling,estimation and control of the torque in different working situations,including vehicle starting and mode switching.Based on components elastic characteristics tests and the analysis of clutch statics,clutch operating characteristics computation model is put forward considering the deformation of the diaphragm spring clutch cover.With the orthogonal experiment and regression analysis,the clutch friction coefficient empirical model is established in which friction coefficient is changing with the sliding velocity and the temperature.Considering the intrinsic relations such as elasticity weakening and wear life of the clutch,the computation model of the clutch torque transmission characteristics in complete wear life is proposed.Through bench test data analysis,the clutch operating characteristics and the torque transmission characteristics of the proposed model are verified.The dynamics model of coaxial parallel HEV power transmission system,the mathematical model of electromechanical actuator and controller model of the clutch are established.In combination with the clutch torque transmission model,automatic diaphragm spring clutch simulation software are developed by Matlab/Simulink,the simulation study on automatic clutch control process has carried out,comparative analysis are made with the test results.Based on Kalman filtering algorithm,clutch transmission torque estimation method is proposed.Discrete state space model of clutch torque estimation is built for HEV mode switching and starting.Using the discrete Kalman filter algorithm to estimate the clutch transmission torque,comparing with the simulation value,the estimation errors of the clutch torque are analyzed.The influence of noise variance,system sampling time to the clutch torque estimation is studied.Using the road test datas,the clutch torque computation result from clutch torque transmission model and estimation result from kalman filter are compared,the effectiveness of the proposed clutch torque estimation method is verified.Based on Kalman filtering,HEV clutch engaging torque tracking PID control strategy is proposed.The clutch torque low pass filter,torque loop proportional controller,travel loop PID controller and feedforward controller are designed.The particle swarm optimization algorithm is used to optimize the PID control parameters.Combining with the clutch torque Kalman filter,clutch torque tracking digital control program is designed.Arms at clutch engaging process in the HEV mode switching and vehicle starting,the clutch torque tracking control is simulated.The results show that the control of the clutch torque can follow setting torque with ignorable errors.Influence of clutch wear and sliding friction temperature on clutch torque tracking control are studied by simulation,and the results show that the proposed control strategy has good stability and robustness.Using HEV road test data,the clutch torque tracking control process is simulated,the results further illustrate that the proposed clutch torque tracking control method is feasible and effective.