Anti-spin control for marine propulsion systems

An anti-spin controller for marine propulsion systems in rough seas is developed. From measurements of motor torque and propeller shaft speed, an observer providing an accurate estimate of the propeller load torque is used to calculate an estimate of the torque loss. A monitoring algorithm utilizing the estimated torque loss detects ventilation incidents, and activates the anti-spin control action. When a ventilation situation is detected, the anti-spin control action will reduce the propeller shaft speed to some optimal value, using a combined power/torque controller. The ultimate goal is to minimize the effect of ventilation, and hence increase the thrust production, limit the transients in the power system and reduce the mechanical wear and tear of the propulsion system components. Simulations are provided to validate the performance of the control scheme.