Patent ID: 8326472
Filing Date: 2012-12-04
Classification: B63H

Abstract:
1. An automatic vessel position holding control method to hold a vessel position and a vessel heading of a vessel on the ocean using an automatic vessel position holding controller which is provided with vessel motion measuring means, wave information estimating means, pitch response value calculating means, wave time-series calculating means, and wave drifting force calculating means, wherein, by the automatic vessel position holding controller, a vessel position holding control is performed including a control in which at least one of a wave drifting force and a wave drifting moment caused by waves is calculated and a feedforward control is performed for at least one of a calculated wave drifting force and a calculated wave drifting moment, comprising measuring, by the vessel motion measuring means, motions of the vessel including at least a pitch and a roll; calculating, by the wave information estimating means, a pitch representative period from a pitch measured time series; estimating, by the wave information estimating means, a wave incident angle from a measured response ratio between a measured pitch and a measured roll based on the pitch representative period using a wave incident angle estimation table prepared in advance; calculating, by the pitch response value calculating means, a pitch response value from the pitch representative period and the wave incident angle using a pitch response value table in short crest irregular waves prepared in advance; calculating, by the wave time-series calculating means, estimated time series of waves by multiplying the pitch measured time series by the inverse of the pitch response value; and calculating, by the wave drifting force calculating means, at least one of the wave drifting force and the wave drifting moment from the estimated time series of waves.