Computational Implementation of LuGre Friction Model in a Revolute Joint with Clearance

Abstract

This paper demonstrates how LuGre friction law can be implemented to model the stick-slip friction in revolute clearance joints of a mechanical system. The effective coefficient of friction is represented as a function of the relative tangential velocity of the contacting bodies, that is, the journal and the bearing, and an internal state. In LuGre friction model, the internal state is considered to be the average bristle deflection of the contacting bodies. By applying the LuGre friction law on a typical slider-crank mechanism, the friction force in the revolute joint having clearance is seen not to have a discontinuity at zero slip velocity throughout the simulation unlike in static friction models. In addition, LuGre model is observed to capture the Stribeck effect which is a phenomenon associated directly with stick-slip friction.