Study On The Engaging Law And Stability Analysis Of Clutch For AMT

Automated Mechanical Transmission(AMT) is based on traditional gear transmission, which has higher transmission efficiency and lower cost than AT. So it has an expansive market and development foreground.The control of clutch is one of the key problems of AMT technology, and abnormal vibration happening during the clutch engagement affects the stability of clutch. So this paper's content has two parts, the first is to design the control strategy of clutch engagement, another is to analyze the stability during clutch engagement.To design the control law of clutch engagement, it is necessary to know the dynamic performance characteristics of diaphragm spring. So the paper established the nolinear relationship between the displacement and the pressure of diaphragm spring, at the same time, the dynamic numeral model of engine was founded based on the experimental data. Then, the paper analyzed the engaging process of clutch, performance indexes and influencing factors, and founded the vehicle dynamic model of the clutch engagement. Through the analysis of all kinds of control methods, the paper used speed-control method to design the controller. The control strategy contained two steps: the first is to judge the driver's intention, the second is to determine the engaging speed according to both driver's intention and rotate speed of engine and driven disk of clutch. At last, according to the control strategy, this paper designed the control law with fuzzy control.In order to study the stability during the clutch engagement, the paper established a five DOF dynamic model to analyze how the friction coefficient influence the system stability. The variation of friction coefficient is one of the primary causes for vibration during the clutch engagement by analyzing system eigenvalue.At last, this paper established the simulation model in Matlab/simulink, the simulation result under different driver intentions show that the control strategy meets the requirements of vehicle start-up. Simulation results of five DOF model show that when the slope of the friction coefficient of friction disc with slip speed is less-than critical value, the clutch engagement is unstable, which accords with the stability analysis. But through controlling the engaging speed, the vibration can be repressed.