Self-excited vibrations induced by friction widely exist in fields of engineering and dailylife. Usually, the unwanted self-excited vibrations cause an early wear of the contacting parts of machines. It seems that up to now not all the possible nonlinear phenomena have been properly understood. Especially such conditions as parameter change and internal resonance have seldom been considered in a multiple-degree-of-freedom system. And study on nonlinear active control strategy is just started. The aim...