US3624783A
Expired / Lapsed
US
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Motion control system
Assignee: Santa Fe International Corp
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Filing: 1970-06-12
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Granted: 1971-11-30
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Expires: 1990-06-12
Abstract
Abstract Disclosed is an open loop control for maintaining constant tension in a cable connecting two bodies. Among the applications of the system are transfer of a load between a pier and a vessel or between two vessels, maintaining constant tension in a cable between two vessels, barge towing, underwater pipelaying, etc. The system includes a motion sensor, and a motion-compensator subsystem to generate a control signal in synchronism with the motion being sensed but at a fixed phase offset in relation thereto. The control signal operates a motor or the like at a fixed speed forward or reverse to compensate for the sensed motion with the phase offset compensating for the reversal time lag between full speed in opposite directions present in the motor system.
Inventors
- 👤 Nuke Ming Chang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 12:10
CPC Classifications
B; B66; B66C; B66C13/00; B66C13/02; B66C13/18; B66C13/22; B66C13/30; B66C2700/00; B66C2700/08; B66C2700/082; Y; Y10; Y10S; Y10S254/00; Y10S254/90
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
97 words
A method of maintaining constant tension in a linking mechanism connecting two bodies subject to an essentially repetitive relative motion comprising the steps of: connecting said linking mechanism to a reversible takeup mechanism haVing a steady state reversal timelag which is a function of its physical parameters, deriving a signal analog of said relative motion, generating a control signal in synchronism with said signal analog but at a predetermined phase advance in relation thereto, said phase advance being a function of said takeup mechanism reversal timelag, and operating said takeup mechanism in response to said control signal.
Claim 2
Independent Claim
97 words
A method of maintaining constant tension in a linking mechanism connecting two bodies subject to an essentially repetitive relative motion comprising the steps of: connecting said linking mechanism to a reversible takeup mechanism haVing a steady state reversal timelag which is a function of its physical parameters, deriving a signal analog of said relative motion, generating a control signal in synchronism with said signal analog but at a predetermined phase advance in relation thereto, said phase advance being a function of said takeup mechanism reversal timelag, and operating said takeup mechanism in response to said control signal.
Claim 3
Dependent Claim
22 words
The method as defined by claim 1 wherein said phase advance is approximately equal to the reversal timelag of said takeup mechanism.
Claim 4
Dependent Claim
26 words
The method as set forth in claim 1 wherein said signal analog of said relative motion is determined by measuring the tension in said linking mechanism.
Claim 5
Dependent Claim
27 words
The method as set forth in claim 1 wherein said signal analog is derived by measuring the motion in a predetermined direction of one of said bodies.
Claim 6
Dependent Claim
30 words
The method as set forth in claim 1 wherein said signal analog is derived by measuring the difference between the actual motions in a given direction of said two bodies.
Claim 7
Dependent Claim
112 words
The method as set forth in claim 1 wherein said step of generating said control signal comprises converting said signal analog to a first binary signal having a first value when said analog is positive with respect to some reference and a second value when said analog is negative with respect to said reference; generating a second binary signal having approximately the same repetition rate as said first binary signal; comparing said first and second binary signals to determine the degree of noncoincidence therebetween; and adjusting the repetition rate of said second binary signal so that the degree of noncoincidence between said first and second binary signals represents said predetermined phase advance.
Claim 8
Dependent Claim
35 words
The method of claim 6 wherein said takeup mechanism is operated in one direction when said control signal has its first value, and in the other direction when said control signal has its second value.
Claim 9
Dependent Claim
62 words
The method as set forth in claim 1 wherein said signal analog has positive and negative values with respect to some reference corresponding to opposite directions of relative motion, and wherein said takeup mechanism is operated in one direction in response to positive values of said signal analog, and in the other direction in response to negative values of said signal analog.
Claim 10
Dependent Claim
21 words
The method as set forth in claim 8 wherein said takeup mechanism is operated at the same speed in both directions.
Claim 11
Dependent Claim
24 words
The method as defined by claim 1 wherein said signal analog is derived by measuring the acceleration of at least one of said bodies.
Claim 12
Dependent Claim
119 words
Apparatus for maintaining constant tension in a linking mechanism connecting two bodies subject to an essentially repetitive relative motion comprising: means for sensing said relative motion and for generating a continuous signal analog thereof; means responsive to said signal analog for generating a control signal in synchronism therewith but having a fixed phase advance in relation thereto; reversible drive means adapted to be coupled to said linking mechanism for controlling the tension therein, said drive means being characterized by a steady state reversal time which is a function of its physical parameters; and control means responsive to said control signal to operate said drive means in one or the other direction in accordance with changes in said relative motion.
Claim 13
Dependent Claim
119 words
Apparatus for maintaining constant tension in a linking mechanism connecting two bodies subject to an essentially repetitive relative motion comprising: means for sensing said relative motion and for generating a continuous signal analog thereof; means responsive to said signal analog for generating a control signal in synchronism therewith but having a fixed phase advance in relation thereto; reversible drive means adapted to be coupled to said linking mechanism for controlling the tension therein, said drive means being characterized by a steady state reversal time which is a function of its physical parameters; and control means responsive to said control signal to operate said drive means in one or the other direction in accordance with changes in said relative motion.
Claim 14
Dependent Claim
24 words
Apparatus as defined in claim 11 wherein the value of said phase advance is a function of the reversal time of said drive means.
Claim 15
Dependent Claim
17 words
Apparatus as defined in claim 11 wherein said phase advance is approximately equal to said reversal time.
Claim 16
Dependent Claim
13 words
Apparatus as defined in claim 11 wherein said sensing means is an accelerometer.
Claim 17
Dependent Claim
37 words
Apparatus as defined in claim 11 wherein said sensing means comprises a motion pickup coupled to each body, and means coupled to said pickups to generate a signal representing the difference between the outputs of said pickups.
Claim 18
Dependent Claim
11 words
Apparatus as defined in claim 15 wherein said pickups are Accelerometers.
Claim 19
Dependent Claim
17 words
Apparatus as defined in claim 11 wherein said signal analog represents the acceleration of said relative motion.
Claim 20
Dependent Claim
19 words
Apparatus as defined in claim 11 wherein said sensing means comprises a load cell coupled into said linking mechanism.
Claim 21
Dependent Claim
144 words
Apparatus as defined in claim 11 wherein said means for generating said control signal comprises means responsive to said signal analog to generate a first binary signal having one value when said analog is positive relative to some reference and a second value when said analog signal is negative relative to said reference; oscillator means for generating a second binary signal having approximately the same repetition rate as said first binary signals; means for comparing said first and second binary signals to generate an error signal representative of the degree of noncoincidence between said first and second signal; correction signal generating means for adding to said error signal a compensation signal representing a predetermined degree of noncoincidence between said first and second signals and means for coupling said correction signal to said oscillator means to control the repetition rate of said second binary signal.
Claim 22
Dependent Claim
49 words
Apparatus as defined in claim 19 further including means responsive to said second binary signal to operate said second binary signal to operate said device means in one direction when said binary signal has one value and in the other direction when said binary signal has its other value.
References Cited (Backward Citations)
US3189195A
Cited
US3469821A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-29 | 1975-05-31 | 1975-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-29 | 1979-05-31 | 1979-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-29 | 1983-05-31 | 1983-11-30 | $7700.00 | Window Closed / Lapsed |