Research On Clutch Reliability Compensation Control Based On Friction Coefficient And Its Rate Of Change

Clutch is one of the key components in the power transmission system of automatic transmission,and its transmission performance directly affects the reliability of the transmission system.When the vehicle starts under severe working conditions such as high temperature and heavy load,the failure probability of the clutch increases greatly.Aiming at this problem,this paper takes the starting clutch of automatic transmission as the research object,first of all,the experimental study on the variation law of clutch friction coefficient is carried out.Secondly,the model is solved by the reliability method of non probability ellipsoid convex set.Finally,the compensation control model considering reliability is established to control the oil pressure.Avoid the clutch working in the critical area for a long time,so as to enhance the reliability of clutch transmission.The contents of this paper are as follows:(1)The basic structure and working principle of the clutch are introduced.Through the experimental study of the friction coefficient variation of the clutch,the change law of the friction coefficient under different working conditions is obtained,and the MAP relation diagram of oil temperature,oil pressure and friction coefficient is set up.According to the test results and the failure analysis of clutch,a failure evaluation model based on friction coefficient is put forward.(2)Based on the non probabilistic convex set theory,the reliability convex model of the clutch is established,and the limit state equation is determined with the friction coefficient and the rate of change as the evaluation index combined with the proposed failure evaluation model of the clutch sliding transmission.A reliability measure based on volume ratio is used to define reliability.According to the actual working conditions,the interval parameters such as oil temperature and oil pressure are divided into intervals.the Monte Carlo method is used to solve the non probabilistic reliability model.Finally,the influence of uncertain parameters on the reliability of clutch transmission is analyzed.(3)The clutch hydraulic control system is analyzed,and a torque control scheme based on pressure feedback is developed.Combined with the study of the reliability of clutch transmission,a compensation control strategy considering reliability is proposed.The fuzzy controller of clutch is designed based on fuzzy control theory,and the simulation model of torque compensation control considering reliability is built.Finally,in order to verify the feasibility of the compensation control scheme,the automatic transmission test platform of the cooperative unit is used to verify the bench test for the compensation control algorithm.The test results show that the reliability of the clutch fuzzy compensation control algorithm considering the reliability is more reliable than the original clutch closed loop control algorithm,which can effectively improve the sliding friction drive of the starting clutch.