Mechanism-oriented control for suppressing start-up judder of vehicle with automatic dry clutch: Experiment and simulation analysis

Abstract

In this paper, a mechanism-oriented control strategy is proposed to cut off the introduction process of negative damping caused by the Stribeck effect for suppressing the vehicle start-up judder. From the experimental analysis, the characteristic frequency of start-up judder is mainly concentrated at about 8.25 Hz, coinciding with the first-order natural frequency of the driveline system. A 13-degree-of-freedom powertrain branched model is established, whose validity and accuracy in reflecting the characteristics of start-up judder are verified by comparing with the experimental results in time–frequency domain. The start-up judder mechanism is profoundly revealed through explaining the introduction of negative damping and the origin of characteristic frequency. The positive-feedback closed loop caused by the negative gradient characteristic of the Stribeck effect is the determining factor that promotes the aggravation of the fluctuation in the rotational speed of clutch-driven plate, which is the manifestation of the negative damping. The core idea of the mechanism-oriented control strategy is to cut off the positive-feedback closed loop, which is achieved by fine-tuning the position of release bearing. The judder-suppression performance behaves well both in simulation and in experiment.