Active control for stick-slip behavior of the marine propeller shaft subjected to friction-induced vibration

A stable rotational speed of the marine propeller shaft is essential to minimize the friction of the supporting bearings and to improve the efficiency of the power system. While, the friction induced vibration of the marine shaft-bearing system seriously affect the performance and reliability of the powertrain. This paper proposes an active control method to suppress the stick-slip behavior of the marine propeller shaft based on state observer. The dynamical response including relative velocity, power spectral density, dynamic friction coefficient and reaction force with various friction model are calculated. The active control with state feedback and internal model principle are applied to track the rotational speed of each segment of the whole shaft. The behavior of the state observer is analyzed through a comparison of actual value and observed value of the tracking for contin-uously varying speeds. The robustness of controlled system is investigated through comparison of overshoot rate and adjustment time with various control parameters. Moreover, a comparison of the observed velocity between present work and previous reference is conducted to validate the applicability of the proposed frictional model. The active control for friction-induced vibration of marine propeller shaft is thus realized based on the adjust-ment of control parameters.