Method and apparatus for actively adjusting and controlling a resonant mass-spring system
First Claim
1. A vibratory inertial force generator including an actively-controlled mass-spring system arranged to be resonantly excited so as to exert a vibratory reaction force on a structure, said system having a mass mounted for movement relative to said structure and having a spring arranged between said mass and structure, wherein the improvement comprises:
- an externally-powered servoactuator mounted on one of said mass and structure and arranged to modulate said vibratory reaction force transmitted from said mass to said structure as a function of the acceleration of said mass so as to controllably modify the resonant frequency of said system.
3 Assignments
0 Petitions
Accused Products
Abstract
An actively-controlled resonant-type force generator (20) is adapted to be attached to a structure (21), and includes a mass (23) mounted for movement relative to the structure and a plurality of springs (22, 24) operatively arranged between the mass and the structure. A servoactuator (26) is arranged to controllably excite the mass-spring system. The actual force (Fa) transmitted from the mass to the structure is compared with a commanded force (Fc) to produce a force error signal (Fe). The actuator is caused to produce a velocity as a function of the error signal. The gain of the closed force loop is selected so that the resonance of the mass-spring system has an effective damping ratio (ζ) greater than about 0.5, and preferably about 0.7. Thus, the mass-spring system will not be substantially resonantly excited by vibrations of the structure near its resonant frequency (ωn).
153 Citations
22 Claims
-
1. A vibratory inertial force generator including an actively-controlled mass-spring system arranged to be resonantly excited so as to exert a vibratory reaction force on a structure, said system having a mass mounted for movement relative to said structure and having a spring arranged between said mass and structure, wherein the improvement comprises:
an externally-powered servoactuator mounted on one of said mass and structure and arranged to modulate said vibratory reaction force transmitted from said mass to said structure as a function of the acceleration of said mass so as to controllably modify the resonant frequency of said system. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
-
15. The method of controlling an active resonant inertial force generator having a movable mass coupled through at least one spring to a structure, comprising the steps of:
-
mounting an externally-powered servoactuator on one of said mass and structure so as to be capable of modulating the vibratory reaction force transmitted between said mass and structure; commanding a desired vibratory force, at a desired frequency, to be exerted on said structure by said generator; modulating said servoactuator so as to excite the mass-spring system and to continuously adjust the natural frequency of the mass-spring system so as to generate a vibratory reaction force acting on said structure at said commanded frequency; measuring said vibratory reaction force; and controlling the modulation of said servoactuator to minimize the difference between said commanded force and said measured vibratory reaction force. - View Dependent Claims (16, 17)
-
-
18. In an actively-controlled mass-spring system having a resonantly-vibrating mass adapted to exert a vibratory reaction force on a vibrating structure at a mounting point in response to an electrical command signal, the improvement which comprises:
-
an externally-powered servoactuator operatively arranged to act on one of said mass and structure; means for providing an electrical command signal reflecting a desired force; and control means responsive to said command signal for modulating said servoactuator so as to cause the resonant frequency of said system to continuously approximate the frequency of said command signal and to resonantly excite the mass-spring system such that the reaction force exerted on said structure is substantially equal to the electrically-commanded force. - View Dependent Claims (19, 20)
-
-
21. A vibratory inertial force generator including an actively-controlled mass-spring system arranged to be resonantly excited so as to exert a vibratory reaction force on a structure, said system having a mass mounted for movement relative to said structure and having a spring arranged between said mass and structure, wherein the improvement comprises:
-
an externally-powered servoactuator mounted on one of said mass and structure and arranged to modulate said vibratory reaction force transmitted from said mass to said structure as a function of the acceleration of said mass so as to controllably modify the resonant frequency of said system; command means for generating an oscillatory force command signal; transducer means arranged to generate a feedback signal proportional to the force transmitted from said mass to said structure; and means for producing an error signal proportional to the difference between said command signal and said feedback signal.
-
-
22. A vibratory inertial force generator including an actively-controlled mass-spring system arranged to be resonantly excited so as to exert a vibratory reaction force on a structure, said system having a mass mounted for movement relative to said structure and having a spring arranged between said mass and structure, wherein the improvement comprises:
-
an externally-powered servoactuator mounted on one of said mass and structure and arranged to modulate said vibratory reaction force transmitted from said mass to said structure as a function of the acceleration of said mass so as to controllably modify the resonant frequency of said system; command means for generating an oscillatory force command signal; transducer means arranged to generate a feedback signal proportional to the acceleration of said mass; means for producing an error signal proportional to the difference between said command signal and said feedback signal; and control means for modulating said servoactuator as a function of said error signal to cause said system resonant frequency to equal that of the oscillatory force command signal, and to further excite the mass-spring system at its modified resonant frequency so that the reaction force exerted on said structure will be essentially equal to the commanded oscillory force.
-
Specification