Model referenced adaptive control to compensate slip-stick transition during clutch engagement

Abstract

Clutches are widely used in various vehicle powertrains. The engagement process of a friction clutch has three phases, i.e., open, slipping, and sticking. Transitions between different phases introduce a discontinuity to the powertrain dynamics, which has been neglected in previous research. A model referenced adaptive controller (MRAC), based on Popov hyper-stability criterion, is designed to compensate the discontinuity. MRAC adjusts the frictional torque along with the errors of the state variables compared with those of a referenced model. The designed MRAC is applied to a clutch in a bus. Simulation and experimental results under fast and slow startup cases show that MRAC can simultaneously reduce vehicle jerk and frictional dissipation when compared with the conventional controller.

Model reference control of conceptual clutched train substituted for vehicular friction clutch

“…Since standing-start maneuver has been described as a typical manifestation of phenomenon on longitudinal oscillations excited by friction clutch engagement [8,9], control algorithm for clutched train synchronization process would be vital important to vehicle driving comfort. Therefore, control-oriented model of clutched train would be built in this section.…”

Feasibility investigation on novel concept of clutched train system to substitute for vehicular friction clutch

“…Standing-start maneuver has been described as a typical manifestation of the phenomenon on longitudinal oscillations excited by the friction clutch engagement (Chen et al, 2011). For this reason, the control-oriented model of clutched train is integrated with the developed control algorithms to investigate longitudinal oscillations excited by the clutched train engagement on the standing-start case particularly.…”

“…It implies that most of control methods used in friction clutch might be transplanted into clutched train system. (Zhang et al, 2002;Chen et al, 2011) Slipping…”

“…It would not only cause mass loss of clutch's friction materials which augments linearly with increasing sliding distance (Vadiraj, 2010), but massive ensuing frictional heat generated during slipping phase also leads to the reduced service life of the clutch. In addition, high non-linearity (Petrun et al, 2012) and discontinuity (Chen et al, 2011) during slip-stick transition are introduced into clutch actuation and vehicular powertrain dynamics. Thereby, various complicated friction models and control algorithms were developed and served for driving comfort and clutch service life.…”

“…These controllers improve the driving comfort during the slipping phase. Meanwhile, other researchers claimed that Model Referenced Control reduces the jerking effect significantly during friction clutch slip-stick transition (Chen et al, 2011;Chen et al, 2012). However, in the aforementioned studies the friction coefficient between the clutch plates is considered to be constant over the whole range of relative sliding velocities, temperature, normal force, direction etc (Petrun et al, 2012), and hence makes it difficult to give an accurate signal to actuator for the estimation of the transmitted clutch torque while previous works by Marklund and Larsson (2007) indicated that the friction coefficient of the clutch plates has a noticeable variation that aroused by the different velocities and temperature.…”