Moving center estimation method and system for boat

Patent metadata

Field	Value
Publication number	US-9650119-B2
Application number	US-201314433753-A
Country	US
Kind code	B2
Filing date	Jul 23, 2013
Priority date	Oct 11, 2012
Publication date	May 16, 2017
Grant date	May 16, 2017

Abstract

In a moving center estimation method, a provisional moving center is set at a predetermined position in a neighborhood of an actual moving center of a hull. A sample thrust having a predetermined magnitude and direction is applied to the provisional moving center by driving the outboard motor, and a magnitude and direction of an angular acceleration generated in the hull by application of the sample thrust is detected. The magnitude of the angular acceleration is compared with a predetermined threshold value, and a position of the provisional moving center is changed and set so that the angular acceleration may converge in the threshold value, when the angular acceleration is larger than the threshold value.

First claim

The invention claimed is:

1. A moving center estimation method for boat which estimates a moving center of a boat equipped with a plurality of outboard motors on a stern side of a hull, the moving center estimation method comprising:
a provisional moving center setter 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 sample thrust applier (a) applying a sample thrust having a predetermined magnitude and direction to the provisional moving center by driving the outboard motor;
a angular acceleration detector (b) detecting a magnitude and direction of an angular acceleration generated in the boat by application of the sample thrust;
a angular acceleration comparator (c) comparing the magnitude of the angular acceleration with a predetermined threshold value;
(d) if the magnitude of the angular acceleration is greater than the predetermined threshold value, changing a position of the provisional moving center, 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
if the magnitude of the angular acceleration is not greater than the predetermined threshold value, setting the provisional moving center as the actual moving center.

2. The moving center estimation method for boat according to claim 1 ,
wherein the provisional moving center is set at a position of ¼ an entire length from a stern of the hull and on a boat center line, in the provisional moving center setting.

3. The moving center estimation method for boat according to claim 1 ,
wherein the sample thrust is applied to the provisional moving center in a direction orthogonal to a boat center line, in the sample thrust application.

4. 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.

5. 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.

Assignees

• Suzuki Motor Corp

Inventors

• Morikami Tadaaki
• Nishio Masaya
• Miyoshi Takanori
• Yumiba Toyohiro

Classifications

• B63H25/24

  by electrical means · CPC title

• B63H25/42

  Steering or dynamic anchoring by propulsive elements (by jets B63H25/46); Steering or dynamic anchoring by propellers used therefor only; Steering or dynamic anchoring by rudders carrying propellers · CPC title

• B63H2020/003

  Arrangements of two, or more outboard propulsion units · CPC title

• B63H21/22 Primary

  the propulsion power units being controlled from exterior of engine room, e.g. from navigation bridge; Arrangements of order telegraphs · CPC title

• B63J2099/008

  Operations & Transport · mapped topic