Method and Apparatus for Active Heave Compensation
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Accused Products
Abstract
Methods and apparatuses for active heave compensation, the method, in certain aspects, including the steps of: (a) measuring with a measurement device (44) the heave of a vessel (10) and outputting a heave signal representative thereof; (b) using said heave signal to compensate for said heave by moving a connection device (20) relative to said vessel (10) as a function of said heave signal, whereby movement due to said heave of a load attached to said vessel via the connection device is reduced; said heave signal comprising errors induced by said measurement device (44) whereby accuracy of said compensation is reduced; (c) processing said heave signal so as to reduce said errors and outputting an adjusted heave signal; and (d) using said adjusted heave signal to move said connection device (20) to compensate for said heave.
38 Citations
85 Claims
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1-66. -66. (canceled)
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67. A method of actively compensating heave of a vessel to which a load is attached, there being a connection device connecting said load to said vessel, which method comprises the steps of:
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(a) measuring with a measurement device the heave of said vessel and outputting a heave signal representative thereof, which heave signal comprises a velocity signal representing velocity of said vessel in response to said heave; (b) using said heave signal to compensate for said heave by moving said connection device relative to said vessel as a function of said heave signal, whereby movement of said load due to said heave is reduced; said heave signal comprising errors induced by said measurement device whereby accuracy of said compensation is reduced, characterised by the steps of; (c) processing said heave signal by determining a velocity correction (vG) and adjusting said velocity signal by said velocity correction so as to reduce said errors and outputting an adjusted heave signal; and (d) using said adjusted heave signal to move said connection device to compensate for said heave. - View Dependent Claims (68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83)
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84. An apparatus for controlling active heave compensation, the arrangement being such that, in use, said apparatus controls movement of a connection device that connects a load to a vessel, which apparatus comprises an input for receiving a heave signal from a measurement device, which heave signal is representative of the heave of said vessel, which heave signal comprises a velocity signal representing velocity of said vessel in response to said heave;
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which apparatus further comprises a memory storing computer executable instructions for performing the steps of; (a) using said heave signal to compensate for said heave by moving said connection device relative to said vessel as a function of said heave signal, whereby movement of said load due to said heave is reduced; said heave signal comprising errors induced by said measurement device whereby accuracy of said compensation is reduced; (b) processing said heave signal by determining a velocity correction (vG) and adjusting said velocity signal by said velocity correction so as to reduce said errors and outputting an adjusted heave signal; and (c) using said adjusted heave signal to move said connection device to compensate for said heave.
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85. A measurement device for measuring heave of a vessel, which measurement device comprises one or more sensor for measuring motion of a vessel, a memory storing computer executable instructions for performing the steps of.
(a) measuring with said one or more sensor the heave of a vessel, and generating a heave signal which comprises a velocity signal representing velocity of said vessel in response to said heave, said heave signal comprising errors induced by said measurement device; - and
(b) processing said heave signal by determining a velocity correction (vG) and adjusting said velocity signal by said velocity correction so as to reduce said errors and outputting an adjusted heave signal.
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Specification