Active Control for Transverse Vibration of the Marine Stern Shaft-Bearing System with LQR Strategy

Abstract

The vibration control is essential to suppress am-plitude and improve efficiency for the marine stern shaft-bearing systems. An active controller for transverse vibra-tion is proposed by a combination of damping absorber and electromagnetic actuator with LQR strategy. The con-troller is designed with control methods, the parameters are defined based on the system and the disturbance input is obtained from experiments. The displacement of suspen-sion travel and soleplate deflection, as well as the velocity of shaft and bearing is investigated. The robustness is ana-lyzed with a pulse disturbance to study the maintenance of stability margins. The results demonstrated that the con-trolled behavior of the LQR strategy is preferable to that of the passive control. Moreover, the effect of damping ab-sorber is explored through results discussion with different damping coefficient. The control weighting matrix is proved to be significant for setting time, overshoot rate and reduction rate of the controlled behavior. A smaller damp-ing coefficient and control weighting matrix are demon-strated to be more satisfied for the control objectives. Therefore, the vibration reduction of the marine stern shaft-bearing systems can be achieved with the proposed LQR strategy.