Adaptive torque tracking control during slip engagement of a dry clutch in vehicle powertrain

Abstract

Dry clutches have been gaining its popularity for use in the transmission systems of small and medium-sized vehicles as well as the engine clutch systems of parallel hybrid vehicles. With this trend, the ability to appropriately control the amount of torque transferred through the dry clutch becomes important. This paper addresses a feedforward control method of clutch torque during slip engagement of a dry clutch utilizing a clutch friction model. In many studies, the clutch friction coefficient is considered as the only uncertain parameter in the clutch friction model. However, the clutch touch point can also serve as a major source of uncertainty in the clutch friction model. Thus, this paper proposes a simultaneous adaptation method to estimate the clutch friction coefficient and the clutch touch point in real time and a feedforward control method of clutch torque during slip engagement of a dry clutch based on the proposed adaptation algorithm. This control approach is applied to the slip engagement control of a dry engine clutch in a parallel hybrid vehicle and its effect is experimentally verified using a production vehicle. (C) 2019 Elsevier Ltd. All rights reserved.