Harmonic analysis of a marine shaft-bearing suspension system and its semi-active control with PID strategy

Abstract

A stable operating state of the marine shaft-bearing system is essential to minimize the vibration level and improve the transmission efficiency of the ship power system. A semi-active control with PID strategy is proposed through an adjustable damping magnetorheological shock absorber and the combination of the electromagnetic actuator based on the existing suspension system. The harmonic response of the system is calculated through transfer function with various suspension stiffness and damping. The controlled behaviors include suspension travel, soleplate deflection, sprung shaft and unsprung bearing, are obtained through Matlab/Simulink. The proposed controller is demonstrated to be applicable through robustness analysis by comparing with passive and LQR control based on the disturbance of pulse width modulation. The controlled behaviors with minor stiffness and significant damping are noticed to be more satisfied through the influence comparison of suspension parameters. The controlled performance includes reduction rate, overshoot rate and setting time with various values of control factors are discussed to prove the suitability. The semi-active control for the transverse vibration of the marine shaft-bearing system is thus realized based on the adjustment of control parameters.