On estimation of dynamic friction

Evidence is mounting that friction is a dynamic phenomenon. Three techniques for estimating dynamic friction are presented. The first uses an observer based on a static model; the second uses an observer that tracks the friction force; the third is based on estimation of the friction coefficient of a correct dynamic model. By simulation it is found that the observer that is based on the correct model performs the best, but all are satisfactory. The results indicate that the dynamic effects of friction in control systems can be dealt with effectively.<>