US3730126A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and means for dynamically stationing a floating vessel
Assignee: Shell USA Inc
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Filing: 1971-07-09
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Granted: 1973-05-01
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Expires: 1991-07-09
Abstract
Abstract A seagoing vessel such as an offshore oil rig is dynamically stationed by measuring the actual position of the vessel with reference to a desired position, filtering the deviation or error signal to remove higher frequency components due to wave action, and using the resultant signal to control multidirectional drive means.
Inventors
- 👤 H Zunderdorp
- 👤 A Berkhout
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 03:12
CPC Classifications
G; G06; G06G; G06G7/00; G06G7/48; G06G7/70; G01; G01S; G01S1/00; G01S1/02; G01S15/00; G01S15/88; G05; G05D; G05D1/00; G05D1/02; G05D1/0206; G05D1/0208
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
200 words
A method for dynamically stationing a floating vessel of the type provided with a means for measuring along at least one coordinate the deviation of the vessel from a desired position and for generating in the time domain a deviation signal representative of the measured deviation and provided with a drive means suitable to be controlled by a control signal derived from the deviation signal to reduce the deviation along the coordinate by generating directional forces tending to move the vessel, said method comprising: filtering the deviation signal by synthetizing a filter impulse response capable of generating from the deViation signal a filter signal representing the portion of the deviation signal resulting from wave action; generating the auto-correlation function of the filter signal by convolving the filter signal with the auto-correlation function of the deviation signal, said auto-correlation function of the filter signal being generated periodically with the oldest auto-correlation function being discarded each time a new autocorrelation function of the filter signal is generated; subtracting the auto-correlation function of the filter signal from the deviation signal to form a filtered signal; and applying the filtered signal to the means used to control the drive means to reduce the deviation.
Claim 2
Independent Claim
200 words
A method for dynamically stationing a floating vessel of the type provided with a means for measuring along at least one coordinate the deviation of the vessel from a desired position and for generating in the time domain a deviation signal representative of the measured deviation and provided with a drive means suitable to be controlled by a control signal derived from the deviation signal to reduce the deviation along the coordinate by generating directional forces tending to move the vessel, said method comprising: filtering the deviation signal by synthetizing a filter impulse response capable of generating from the deViation signal a filter signal representing the portion of the deviation signal resulting from wave action; generating the auto-correlation function of the filter signal by convolving the filter signal with the auto-correlation function of the deviation signal, said auto-correlation function of the filter signal being generated periodically with the oldest auto-correlation function being discarded each time a new autocorrelation function of the filter signal is generated; subtracting the auto-correlation function of the filter signal from the deviation signal to form a filtered signal; and applying the filtered signal to the means used to control the drive means to reduce the deviation.
Claim 3
Dependent Claim
23 words
A method according to claim 1, wherein the length of the auto-correlation function of the deviation signal is between 200 and 1000 seconds.
Claim 4
Dependent Claim
2 words
a controller,
Claim 5
Dependent Claim
2 words
a controller,
Claim 6
Dependent Claim
22 words
an output suitable to be connected to means adapted to reduce the deviation of a vessel as measured along the co-ordinate, and
Claim 7
Dependent Claim
22 words
an output suitable to be connected to means adapted to reduce the deviation of a vessel as measured along the co-ordinate, and
Claim 8
Dependent Claim
25 words
A method according to claim 2, wherein the time gate over which the deviation signal is auto-correlated has a length between 200 and 2000 seconds.
Claim 9
Dependent Claim
19 words
A method according to claim 1, wherein the length of the zero-phase filter is between 50 and 250 seconds.
Claim 10
Dependent Claim
67 words
a filter for attenuating at least a selected portion of the wave component present in the deviation signal, said filter including a system for sampling the deviation signal and storing a limited number of samples with relation to the sampling time, by discarding the oldest sample each time a new sample is added, the controller and the filter being interposed between the measuring system and the output.
Claim 11
Dependent Claim
67 words
a filter for attenuating at least a selected portion of the wave component present in the deviation signal, said filter including a system for sampling the deviation signal and storing a limited number of samples with relation to the sampling time, by discarding the oldest sample each time a new sample is added, the controller and the filter being interposed between the measuring system and the output.
Claim 12
Dependent Claim
19 words
A method according to claim 1, wherein the length Tf of the filter is between 50 and 250 seconds.
Claim 13
Dependent Claim
19 words
A method according to claim 1, wherein the filter impulse response is synthetized periodically every 1 to 100 seconds.
Claim 14
Dependent Claim
18 words
A method according to claim 6 wherein the deviation signal is sampled periodically every 0.1 to 1 second.
Claim 15
Dependent Claim
8 words
Apparatus for dynamically stationing a floating vessel, comprising:
Claim 16
Dependent Claim
8 words
Apparatus for dynamically stationing a floating vessel, comprising:
Claim 17
Dependent Claim
42 words
Apparatus according to claim 8, wherein the filter includes a system for synthetizing a filter impulse response, calculating means for convolving this impulse response with the deviation signal and a subtractor for subtracting the result of this convolution from the deviation signal.
Claim 18
Dependent Claim
107 words
Apparatus according to claim 8, wherein the filter includes a system for calculating the auto-correlation function of the deviation signal, a system for calculating a filter impulse response, which when convolved within a time gate 0 - Tf, Tf being the filter length, with the auto-correlation of the deviation signal will generate the auto-correlation function of that part of the deviation signal which is in the frequency band comprising the selected part of the wave component of the deviation signal, a system for convolving this filter impulse response with the deviation signal, and a subtractor for subtracting the result of this latter convolution from the deviation signal.
Claim 19
Dependent Claim
100 words
Apparatus according to claim 10, including a system for calculating the auto-correlation function of that part of the deviation signal which is in the frequency band comprising the selected part of the wave component of the deviation signal by convolving the auto-correlation function of the deviation signal with the impulse response of a filter having an amplitude spectrum with relatively high values for the frequency band comprising the selected part of the wave component present in the deviation signal and relatively low values for frequencies outside this band, and further hAving a phase spectrum that is zero for all frequencies.
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) | 1976-04-30 | 1976-10-30 | 1977-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-30 | 1980-10-30 | 1981-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-30 | 1984-10-30 | 1985-05-01 | $7700.00 | Window Closed / Lapsed |