Online estimation of time-varying torque characteristics of automotive clutches using a control oriented model

Many concepts for controlling automated clutches use the clutch characteristic as the quasi-steady-state model of torque transmission. In this case, the accuracy of the clutch characteristic used has a significant influence on the quality of control that can be achieved and consequently affects criteria as important as comfort, shifting time or component strain during operation. As a result, it is often necessary to identify changes in transmission behavior of the clutch at the earliest possible stage and adjust the clutch characteristic accordingly. Taking a physics-based approach, this paper focuses on modeling clutch characteristics with the intention of using the model within existing control structures. It also presents a method that is used online for identifying constant or time-varying parameters of the characteristic model developed.