Driveline modeling and estimation of individual clutch torque during gear shifts for dual clutch transmission

Abstract

The purpose of the proposed work centers on the unprecedented task of accurately estimating the torque transmitted through each clutch of the dual clutch transmission. This is to possibly improve the clutch control performance during vehicle launch and gearshifts and to elongate the clutch life. Such goal is attained by only using the measurements and data that are already available in current production vehicles. The suggested estimator requires the speed measurements of engine, input shafts, and wheels, and nominal engine torque information obtained as a function of driver input and engine speed. By synthesizing the estimations obtained by shaft model-based observer, unknown input observers, and adaptive output torque observer, the novel algorithm to estimate the torque of each clutch separately is developed. Stability of the entire combined observer system is analyzed as well. In the process of developing the transfer shaft model-based observer, an original approach for the driveline modeling is proposed. The driveline modeling procedures include compliance model of each transfer shafts with the convenient methods to express the clutch torque without having to use complex clutch friction models, and the developed model is compared with the actual experiment data to validate its accuracy. The effectiveness of the individual clutch torque estimator is demonstrated both through simulations using SimDriveline, and tests on an actual vehicle equipped with a dual clutch transmission.