Moving center estimation method and system for boat

A moving center estimation system for boat which is configured, in a boat equipped with an outboard motor on a stern side of a hull, to be able to control shift, throttle, and steering of the outboard motor by an operation of a joystick by a by-wire method via a helm controller and which estimates a moving center of the boat, the moving center estimation system comprising a processor configured to perform the following:

• setting a provisional moving center at a standard distance between a reference point on the hull and the provisional moving center and offset from an actual moving center of the boat;
• (a) applying a sample thrust having a predetermined magnitude and direction to the provisional moving center by driving the outboard motor;
• (b) detecting a magnitude and direction of an angular acceleration generated in the boat by application of the sample thrust;
• (c) comparing the magnitude of me angular acceleration, with a predetermined threshold value;
• (d) changing a position of the provisional moving center if the magnitude of the angular acceleration is larger than the predetermined threshold value, and then repeating steps (a)-(d);
• wherein the position to be changed of the provisional moving center is caculated by using dichotomy to determine a moving distance of the provisional moving center, an initial moving distance being ½ of the standard distance and each subsequent moving distance further reduced by ½, and shortens a distance between the actual moving center and the provisional moving center, in the provisional moving center changing and setting;
• and
• setting the provisional moving center as the actual moving center if the magnitude of the angular acceleration is not larger than the predetermined threshold value.

A computer readable non-transitory recording medium with a program for causing a computer to function as each device of a moving center estimation system for boat which is configured, in a boat equipped with an outboard motor on a stern side of a hull, to be able to control shift, throttle, and steering of the outboard motor by an operation of a joystick by a by-wire method via a helm controller and which estimates a moving center of the boat, the moving center estimation system comprising a processor configured to perform the following:

• setting a provisional moving center at a standard distance between a reference point on the hull and the provisional moving center and offset from an actual moving center of the boat;
• (a) applying a sample thrust having a predetermined magnitude and direction to the provisional moving center by driving the outboard motor;
• (b) detecting a magnitude and direction of an angular acceleration generated in the boat by application of the sample thrust;
• (c) comparing the magnitude of the angular acceleration with a predetermined threshold value;
• (d) changing a position of the provisional moving center if the magnitude of the angular acceleration is larger than the predetermined threshold value, and then repeating steps (a)-(d);
• wherein the position to be changed of the provisional moving center is calculated by using dichotomy to determine a moving distance of the provisional moving center, an initial moving distance being ½ of the standard distance and each subsequent moving distance further reduced by ½, and shortens a distance between the actual moving center and the provisional moving center, in the provisional moving center changing and setting;
• and
• setting the provisional moving center as the actual moving center if the magnitude of the angular acceleration is not larger than the predetermined threshold value.