Comparisons of two dynamic friction models

Two recent dynamic friction models, the LuGre model and a model by Bliman and Sorine, are investigated and compared. Comparisons are made of captured friction phenomena, behaviour at zero crossings of the velocity and computational issues. Limit cycles in position control of a simple servo with dynamic friction are investigated by means of single input describing function analysis. Both models give reasonable results in the describing function analysis. The LuGre model exhibits a richer behaviour in terms of friction phenomena. The Bliman-Sorine model can be problematic to use because of poor damping properties at zero crossings of the velocity.