US4429496A
Expired / Lapsed
US
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Method and apparatus for active control of flexible structures
Assignee: SOTHERN CALIFORNIA UNIVERSITY OF
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Filing: 1980-12-24
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Granted: 1984-02-07
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Expires: 2000-12-24
Abstract
Abstract A method and apparatus for active control of flexible structures subjected to shocks such as earthquake ground motion. In a first embodiment, the deflection of the structure beyond a prescribed threshold triggers a corrective pulse of mechanical energy which is applied within one period of the structure's lowest mode of vibration. The pulse serves to disorganize the buildup of harmonic motion. In a second embodiment, a pulse, calculated at each deflection cross-over point (during vibration), is applied to the structure in a direction opposite to that of its instantaneous velocity to effect active damping of the motion.
Inventors
- 👤 Sami F. Masri
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:10
CPC Classifications
E; E04; E04B; E04B1/00; E04B1/62; E04B1/92; E04B1/98; E04H; E04H9/00; E04H9/02; F; F16; F16F; F16F15/00; F16F15/02
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
95 words
A method for minimizing the stress to, and/or deformation of, a flexible structure subjected to a dynamic environment comprising the steps of: (a) selecting a threshold state for said structure; (b) sensing the state of said structure in response to said dynamic environment; (c) transmitting the value of at least one corrective energy pulse only when the state of said structure exceeds said threshold; and (d) applying at least one corrective pulse to said structure within one period of its lowest mode of vibration to disorganize the buildup of the amplitude of harmonic vibrations therein.
Claim 2
Independent Claim
95 words
A method for minimizing the stress to, and/or deformation of, a flexible structure subjected to a dynamic environment comprising the steps of: (a) selecting a threshold state for said structure; (b) sensing the state of said structure in response to said dynamic environment; (c) transmitting the value of at least one corrective energy pulse only when the state of said structure exceeds said threshold; and (d) applying at least one corrective pulse to said structure within one period of its lowest mode of vibration to disorganize the buildup of the amplitude of harmonic vibrations therein.
Claim 3
Dependent Claim
58 words
A method as defined in claim 1 wherein the step of calculating the value of at least one corrective energy pulse includes: (a) establishing a cost function which relates stress to said at least one pulse; and (b) choosing the value of said at least one pulse so that the value of said cost function is a minimum.
Claim 4
Independent Claim
102 words
A method for minimizing the stress to, and/or deformation of, a flexible structure subjected to a dynamic environment, comprising the steps of: (a) sensing crossover points of vibration of said structure; (b) determining the magnitude and direction of the velocity of vibration of said structure at each crossover; (c) transmitting at least one corrective energy pulse, said pulse being of opposite direction to said velocity and of magnitude which is a function of the magnitude of said velocity; and (d) applying said energy pulse to said structure at substantially said crossover point to achieve nonlinear damping of the motion of said structure.
Claim 5
Independent Claim
102 words
A method for minimizing the stress to, and/or deformation of, a flexible structure subjected to a dynamic environment, comprising the steps of: (a) sensing crossover points of vibration of said structure; (b) determining the magnitude and direction of the velocity of vibration of said structure at each crossover; (c) transmitting at least one corrective energy pulse, said pulse being of opposite direction to said velocity and of magnitude which is a function of the magnitude of said velocity; and (d) applying said energy pulse to said structure at substantially said crossover point to achieve nonlinear damping of the motion of said structure.
Claim 6
Dependent Claim
44 words
A method as defined in claim 3 additionally including the steps of: (a) establishing a threshold energy pulse; and (b) applying said energy pulse to said structure only when its value as calculated exceeds said threshold to minimize the utilization of corrective pulse energy.
Claim 7
Independent Claim
52 words
A system for minimizing the stress to a structure subjected to a shock, comprising: (a) a sensor to detect the state of said structure; (b) means responsive to the state of said structure for producing a control signal; and (c) at least one pulse generator comprising a rocket, responsive to said signal.
Claim 8
Independent Claim
52 words
A system for minimizing the stress to a structure subjected to a shock, comprising: (a) a sensor to detect the state of said structure; (b) means responsive to the state of said structure for producing a control signal; and (c) at least one pulse generator comprising a rocket, responsive to said signal.
Claim 9
Dependent Claim
13 words
A system as defined in claim 5 wherein said means includes a microprocessor.
Claim 10
Independent Claim
50 words
A system for minimizing the stress to a structure subjected to a shock, comprising: (a) a sensor to detect the state of said structure; (b) means responsive to the state of said structure for producing a control signal; and (c) at least one gas pulse generator responsive to said signal.
Claim 11
Independent Claim
50 words
A system for minimizing the stress to a structure subjected to a shock, comprising: (a) a sensor to detect the state of said structure; (b) means responsive to the state of said structure for producing a control signal; and (c) at least one gas pulse generator responsive to said signal.
Claim 12
Dependent Claim
13 words
A system as defined in claim 7 wherein said means include a microprocessor.
Claim 13
Independent Claim
96 words
A system for minimizing the stress to a structure subjected to a shock, comprising: (a) a sensor to detect the state of said structure; (b) means responsive to the state of said structure for producing a control signal; (c) means for transmitting the value of at least one corrective energy pulse only when the state of said structure exceeds a predetermined threshold state; and (d) means for applying at least one corrective pulse to said structure within one period of its lowest mode of vibration to disorganize the build-up of the amplitude of harmonic vibrations therein.
Claim 14
Independent Claim
96 words
A system for minimizing the stress to a structure subjected to a shock, comprising: (a) a sensor to detect the state of said structure; (b) means responsive to the state of said structure for producing a control signal; (c) means for transmitting the value of at least one corrective energy pulse only when the state of said structure exceeds a predetermined threshold state; and (d) means for applying at least one corrective pulse to said structure within one period of its lowest mode of vibration to disorganize the build-up of the amplitude of harmonic vibrations therein.
Claim 15
Independent Claim
102 words
A system for minimizing the stress to a structure subjected to a shock, comprising: (a) means for sensing crossover points of vibration of said structure; (b) means for determining the magnitude and direction of the velocity of vibration of said structure at each crossover; (c) means for transmitting at least one corrective energy pulse, said pulse being of opposite direction to said velocity and of magnitude which is a function of the magnitude of said velocity; and (d) means for applying said energy pulse to said structure at substantially said crossover point to achieve nonlinear damping of the motion of said structure.
Claim 16
Independent Claim
102 words
A system for minimizing the stress to a structure subjected to a shock, comprising: (a) means for sensing crossover points of vibration of said structure; (b) means for determining the magnitude and direction of the velocity of vibration of said structure at each crossover; (c) means for transmitting at least one corrective energy pulse, said pulse being of opposite direction to said velocity and of magnitude which is a function of the magnitude of said velocity; and (d) means for applying said energy pulse to said structure at substantially said crossover point to achieve nonlinear damping of the motion of said structure.
Claim 17
Dependent Claim
19 words
A building comprising, in combination: (a) a flexible main frame; and (b) a system of claim 9 or 10.
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) | 1987-02-06 | 1987-08-08 | 1988-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-06 | 1991-08-08 | 1992-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-06 | 1995-08-08 | 1996-02-07 | $7700.00 | Window Closed / Lapsed |