US3576977A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System and method for controlling the positioning system of a pipelaying vessel
Assignee: Shell USA Inc
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Filing: 1968-08-26
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Granted: 1971-05-04
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Expires: 1988-08-26
Abstract
Abstract A system and method for controlling the movement, position and orientation of a pipelaying vessel in a manner designed to permit moving the vessel along a desired route while maintaining a desired tension in the pipe and while minimizing the bending forces in the pipe and pipe support structure which result from crosscurrents or misalignment of the vessel. Vessel movement along the route may be at a selected steady rate or may be intermittent and synchronized with the pipeline assembly process being conducted onboard.
Inventors
- 👤 Robert H Kolb
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:06
CPC Classifications
G; G05; G05D; G05D1/00; G05D1/02; G05D1/0206; B; B63; B63H; B63H25/00; B63H25/02; B63H25/04
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
426 words
A method for controlling the movement and heading of a pipelaying vessel, said vessel having a plurality of propulsion means disposed on the vessel to effect movement thereof, so as to lay a pipeline along a predetermined route on the bottom of a body of water while simultaneously maintaining a selected tension applied to the inboard end of the pipeline and maintaining a vessel heading which will assure a selected safe stress distribution in the pipe support structure or stinger at the rear of the vessel and in the pipe in the vicinity of said structure, said method comprising: measuring the pipe-bending force and generating a heading error signal proportional to the difference between the measured force and the desired pipe-bending force; measuring the tension existing in the pipeline at its inboard end where it is being held fixed relative to the vessel or being payed out or pulled in at a given rate and generating a tension error signal proportional to the difference between the measured tension and the desired tension; measuring the deviation of the vessel from the desired route line in a direction transverse to the route line and generating a route error signal proportional to that deviation; applying the heading error signal to the vessel-positioning means in such a manner as to cause the positioning means to generate a turning force acting to establish a vessel heading which will restore the measured bending force in the pipe to its desired value and hence the heading error signal to zero; applying the tension error signal to the vessel positioning means in such a manner as to cause the positioning means to generate a force acting to move the vessel along the route heading irrespective of the vessel''s actual heading in a direction which will restore the tension in the pipeline at its inboard end to the desired value and hence the tension error signal to zero; applying the route error signal to the vessel-positioning means in such a manner as to cause the positioning means to generate a turning couple acting to move the vessel transversely to the route direction irrespective of the vessel''s actual heading in a direction which will restore the vessel to its desired position relative to the route centerline and hence the route error signal to zero; and controlling the timing and the rate at which pipe is payed out or reeled in to control the vessel moveup along the route by controlling the timing and rate at which pipe is allowed to be payed out or reeled in.
Claim 2
Independent Claim
426 words
A method for controlling the movement and heading of a pipelaying vessel, said vessel having a plurality of propulsion means disposed on the vessel to effect movement thereof, so as to lay a pipeline along a predetermined route on the bottom of a body of water while simultaneously maintaining a selected tension applied to the inboard end of the pipeline and maintaining a vessel heading which will assure a selected safe stress distribution in the pipe support structure or stinger at the rear of the vessel and in the pipe in the vicinity of said structure, said method comprising: measuring the pipe-bending force and generating a heading error signal proportional to the difference between the measured force and the desired pipe-bending force; measuring the tension existing in the pipeline at its inboard end where it is being held fixed relative to the vessel or being payed out or pulled in at a given rate and generating a tension error signal proportional to the difference between the measured tension and the desired tension; measuring the deviation of the vessel from the desired route line in a direction transverse to the route line and generating a route error signal proportional to that deviation; applying the heading error signal to the vessel-positioning means in such a manner as to cause the positioning means to generate a turning force acting to establish a vessel heading which will restore the measured bending force in the pipe to its desired value and hence the heading error signal to zero; applying the tension error signal to the vessel positioning means in such a manner as to cause the positioning means to generate a force acting to move the vessel along the route heading irrespective of the vessel''s actual heading in a direction which will restore the tension in the pipeline at its inboard end to the desired value and hence the tension error signal to zero; applying the route error signal to the vessel-positioning means in such a manner as to cause the positioning means to generate a turning couple acting to move the vessel transversely to the route direction irrespective of the vessel''s actual heading in a direction which will restore the vessel to its desired position relative to the route centerline and hence the route error signal to zero; and controlling the timing and the rate at which pipe is payed out or reeled in to control the vessel moveup along the route by controlling the timing and rate at which pipe is allowed to be payed out or reeled in.
Claim 3
Dependent Claim
146 words
The method of claim 1 wherein the tension error signal calling for positioning force along the route direction and the route error signal calling for positioning force transverse to the route direction are resolved into equivalent error signals calling for force along the fore and aft axis of the vessel and for force along the athwartship axis of the vessel, applying these error signals through three-mode controllers to the positioning means to cause the positioning means to generate forces along the respective axis of the vessel and applying the heading error signal to the positioning means through a similar controller, so that the gain and time constants of the control system can be adjusted to match the dynamic characteristics of the vessel and its positioning means in the vessels three natural modes, fore and aft translation, lateral translation and rotation about the vertical or yaw axis.
Claim 4
Dependent Claim
151 words
The method of claim 2 and in addition applying the signal cAlling for force in a fore and aft direction to first positioning means fixed in attitude so as to apply reversible force only along the longitudinal axis of the vessel, and applying the signal calling for force in an athwartship direction to second positioning means fixed in attitude so as to apply a reversible force only along the direction of the athwartship or pitch axis of the vessel, and applying the signal calling for a rotational force about the yaw axis in equal and opposite amounts to a third positioning means fixed in parallel attitudes and separated by a significant horizontal distance so as to apply a reversible turning force about the yaw axis, one of said third positioning means being located at the bow of the vessel and one of said third positioning means being located at the stern.
Claim 5
Dependent Claim
140 words
The method of claim 2 wherein the signal calling for force in a fore and aft direction is vectorially combined with the signal calling for force in a lateral direction into a single force signal having a vectorially equivalent amplitude and direction angle suitable for controlling respectively the thrust and direction of a steerable thrust unit and applying said single force signal to at least two such steerable thruster units separated by a significant horizontal distance so that the signal calling for a turning force can be differentially added in vectorially with the longitudinal and lateral force signals to modify the thrust output and direction of the two units in such a way as to provide the required turning force, said arrangement being adaptable to any desired number of steerable thrusters arranged in the most efficient or most convenient pattern.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-03 | 1974-11-02 | 1975-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-03 | 1978-11-02 | 1979-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-03 | 1982-11-02 | 1983-05-04 | $7700.00 | Window Closed / Lapsed |