This paper seeks to solve the problem of excessive energy consumption caused by the excessive amplitude of the rudder angle and high frequency of rudder angle change during ship course-keeping.

A closed-loop gain shaping algorithm (CGSA) is used to design the controller; a double nonlinear feedback algorithm is introduced; the steering amplitude and frequency are reduced by a combination of the bipolar S-function and arc-tangent function; and the whole control system is controlled by the positive feedback method.

The simulation results show that the proposed double nonlinear feedback algorithm improves the comprehensive energy-saving evaluation index of steering gear energy consumption by 31.53% and 18.63% under Beaufort No. 6 and Beaufort No. 8 respectively.

It is verified that the double nonlinear feedback method has a positive effect on saving the power consumption of the steering gear and reducing carbon emissions in the course of ship navigation, and an equivalent control effect of positive feedback and negative feedback, providing valuable references for the study of ship course-keeping control.