Second-order LuGre friction model

A second-order LuGre friction model is presented which can be viewed as an extension of the well known LuGre friction model. This model is based on a dynamic extension, which can be seen as an extra dynamic to capture some kind of periodic motion produced by the bristles in motion. The additional dynamic can be viewed as an internal disturbance due to the vibration associated with the use of motors. Our model can capture the friction phenomena of the original LuGre friction model and presents two new behaviors, one is the multi-loop behavior in the hysteresis curve when velocity is varied during unidirectional motion, and the other, in the presliding motion curve of friction force versus displacement in the spring regime, where two jumps appear.Postprint (published version

An integral friction model

In this paper, an integral friction model is proposed, defining separately the Dahl, the Stribeck and the microviscous effects. The model is based on an integral closed form solution of the Dahl model. It is shown by simulation that the model is consistent with the LuGre model, while being computationally more efficient. A limit solution of the proposed model avoids the nonphysical drifts, a drawback of the LuGre model recently addressed in the literature