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Automatic vessel position holding control method and controller

  • US 8,326,472 B2
  • Filed: 08/22/2011
  • Issued: 12/04/2012
  • Est. Priority Date: 04/15/2005
  • Status: Active Grant
First Claim
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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, comprisingmeasuring, 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.

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