Modeling of an Automotive Planetary Gear Set Based on Karnopp Model for Clutch Friction

Abstract

Planetary gear sets of automotive automatic transmissions include several hydraulic and one-way clutches. Clutch friction is traditionally described by the generalized, Stribeck, speed-dependent static function approximated by a steep straight line in the zero-speed region (so-called classical friction model). Another approach based on the Karnopp clutch friction model is proposed in this paper. Simulation results for park/reverse engagement and 1–2 upshift shows that the proposed gear set modeling method compared to the classical friction modelbased method yields significant improvement with respect to simulation time, as well as accuracy.