Antispin Thruster Control for Ships

This paper considers the control of thrusters and propellers on ships in extreme operating conditions. In normal operating conditions, recent results have demonstrated that torque and power thruster control will lead to reduced mechanical wear and tear of the propulsion unit, more accurate thrust production, and more predictable power consumption when compared to conventional shaft speed control. In high seas, however, when the propeller may be subject to large thrust losses due to ventilation and in-and-out-of-water effects, torque and power thruster control will lead to propeller racing. This may cause structural damage to the propeller, increase mechanical wear and tear, and give excessive power peaks. To facilitate the use of torque and power control in extreme conditions as well as in normal conditions, an antispin thruster controller is developed, analyzed, and experimentally tested on a model-scale propeller.