Rudder Roll Stabilization Based on Arc Tangent Nonlinear Feedback for Ships

Abstract

The rudder is used for damping the roll motion of a ship. Study of this motion is the essence of this paper. The responses of yaw and roll motions are different as the rudder angle varies. The low frequency motion of the rudder mainly affects the ship’s yaw motion, whereas the high frequency motion of the rudder mainly affects the roll motion. As long as the controller is well designed, the characteristic of the rudder can be used to reduce the roll motion. In order to save energy and reduce steer frequency, a nonlinear feedback controller is proposed based on the arc tangent function processing feedback error to save energy consumption. In addition, a ZOH component is applied in the system to reduce the steer frequency. In heavy sea state, simulation results illustrate that controllers based on pole assignment with and without nonlinear feedback can reduce roll motion by 32.1% and 30.3%, respectively, when the rudder turn rate is limited within 7°/s. Furthermore, the former reduces the amplitude of rudder angle by 23.3% compared with the latter, which means the nonlinear feedback control consumes less energy. Consequently, the ZOH can lower steer frequency to once every 1 s, which protects steering gear from abrasion.

Adaptive neural network control of zero speed ship rolling motion based on state observer

“…The ship's rolling motion has always been one of the key factors threatening the personal safety of the ship itself and its crew. For this reason, scholars have proposed a variety of solutions for ship rolling motion, such as anti-rolling tanks [1], rudder anti-rolling [2] and fin anti-rolling [3]. Among them, the fin anti-rolling has the best effect, which can reach more than 80% [4].…”

Adaptive Neural Network Control of Zero-Speed Vessel Fin Stabilizer Based on Command Filter

“…Vessels in navigation operations may be easily disturbed by harsh environmental factors such as wind, waves, currents, etc., and violent rolling motions may threaten the life and safety of the vessel itself, which also may cause capsizing or other major accidents of vessel destruction and death [1]. In this context, scholars of the ocean engineering community have proposed many effective anti-rolling methods, such as installing bilge keels [2], using a rudder for stabilization [3], adding an anti-rolling tank [4], installing anti-rolling fins [5], etc. The works [6,7] pointed out that a bilge keel can reduce the roll angle of the vessel by about 20%, an anti-rolling tank can reduce the roll by up to 50%, and a rudder can reduce the roll by about 60%.…”

Investigation of a Cabin Suspended and Articulated Rescue Vessel in Terms of Motion Reduction

“…Because rudder stabilizers require large amounts of power and large rudder speeds, the steering gears of civil ships must be modified before the installation of these gears. In addition, the rudder stabilizer controller is highly sensitive to ship parameters because slight changes in the ship structure, ship loading, ship speed, and steering gear parameters will reduce the anti-rolling effect and even make the anti-rolling control fail [9]. (2) The second method involves shifting a certain quantity of mass to generate an anti-rolling moment.…”