US5126641A — Bidirectional variable reluctance actuator and sy…

Claim 1

Independent Claim 114 words

Bidirectional variable reluctance actuator comprising a pair of electromagnets physically connected together through a common structural element, at least one armature disposed between the pair of electromagnets, and a force control means for controlling the electromagnetic forces applied to the armature by the electromagnets; wherein the electromagnets are constructed and arranged relative to said armature in a manner causing the electromagnets to act on said armature with oppositely directed forces; and wherein said force control means comprises a flux linkage control means for producing a relationship between a net force produced on said armature by said electromagnets and an applied reference signal which is substantially linear throughout the range of motion of the armature.

Claim 2

Dependent Claim 114 words

Bidirectional variable reluctance actuator comprising a pair of electromagnets physically connected together through a common structural element, at least one armature disposed between the pair of electromagnets, and a force control means for controlling the electromagnetic forces applied to the armature by the electromagnets; wherein the electromagnets are constructed and arranged relative to said armature in a manner causing the electromagnets to act on said armature with oppositely directed forces; and wherein said force control means comprises a flux linkage control means for producing a relationship between a net force produced on said armature by said electromagnets and an applied reference signal which is substantially linear throughout the range of motion of the armature.

Claim 3

Dependent Claim 79 words

Bidirectional variable reluctance actuator according to claim 1, wherein said force control means further comprises controlled voltage sources for driving the electromagnets; wherein the flux linkage control means is slaved to said reference signal; and wherein the flux control means controls said voltage sources as a function of the difference between a desired value of said net force represented by said reference signal and an actual value of said net force which is determined by said flux control means.

Claim 4

Dependent Claim 34 words

Bidirectional variable reluctance actuator according to claim 2, wherein said force control means is operable for causing said net force to be constant with variations in armature position and velocity relative to the electromagnets.

Claim 5

Dependent Claim 43 words

Bidirectional variable reluctance actuator according to claim 3, wherein, for active attenuation of structure borne vibration and noise, one of said at least one armature and said electromagnets is carried by a vibrating structure and the other is carried by a reaction mass.

Claim 6

Dependent Claim 16 words

Bidirectional variable reluctance actuator according to claim 4, wherein said vibrating structure is a rotating shaft.

Claim 7

Dependent Claim 44 words

Bidirectional variable reluctance actuator according to claim 5, wherein said one of the armature and the electromagnets that is carried by the vibrating structure is carried by an annular disc mounted on said shaft, and said reaction mass is floated relative to said disc.

Claim 8

Dependent Claim 31 words

Bidirectional variable reluctance actuator according to claim 3, wherein, for active attenuation of structure borne vibration and noise, the actuator further comprises means for mounting the actuator to a vibrating structure.

Claim 9

Dependent Claim 31 words

Bidirectional variable reluctance actuator according to claim 7, wherein said one of the armature and the electromagnets that is carried by vibrating structure is fixedly secured to the means for mounting.

Claim 10

Dependent Claim 17 words

Bidirectional variable reluctance actuator according to claim 8, wherein said means for mounting comprises a pipe clamp.

Claim 11

Dependent Claim 16 words

Bidirectional variable reluctance actuator according to claim 8, wherein said means for mounting comprises a plate.

Claim 12

Dependent Claim 22 words

Bidirectional variable reluctance actuator according to claim 4, further comprising hydrostatic means for floating the reaction mass relative to the vibrating structure.

Claim 13

Dependent Claim 22 words

Bidirectional variable reluctance actuator according to claim 4, further comprising electromagnetic means for floating the reaction mass relative to the vibrating structure.

Claim 14

Dependent Claim 43 words

Bidirectional variable reluctance actuator according to claim 1, wherein, for active attenuation of structure borne vibration and noise, one of said at least one armature and said electromagnets is carried by a vibrating structure and the other is carried by a reaction mass.

Claim 15

Dependent Claim 16 words

Bidirectional variable reluctance actuator according to claim 13, wherein said vibrating structure is a rotating shaft.

Claim 16

Dependent Claim 44 words

Bidirectional variable reluctance actuator according to claim 14, wherein said one of the armature and the electromagnets that is carried by the vibrating structure is carried by an annular disc mounted on said shaft, and said reaction mass is floated relative to said disc.

Claim 17

Dependent Claim 31 words

Bidirectional variable reluctance actuator according to claim 1, wherein, for active attenuation of structure borne vibration and noise, the actuator further comprises means for mounting the actuator to a vibrating structure.

Claim 18

Dependent Claim 31 words

Bidirectional variable reluctance actuator according to claim 16, wherein said one of the armature and the electromagnets that is carried by vibrating structure is fixedly secured to the means for mounting.

Claim 19

Dependent Claim 17 words

Bidirectional variable reluctance actuator according to claim 17, wherein said means for mounting comprises a pipe clamp.

Claim 20

Dependent Claim 16 words

Bidirectional variable reluctance actuator according to claim 17, wherein said means for mounting comprises a plate.

Claim 21

Dependent Claim 22 words

Bidirectional variable reluctance actuator according to claim 13, further comprising hydrostatic means for floating the reaction mass relative to the vibrating structure.

Claim 22

Dependent Claim 22 words

Bidirectional variable reluctance actuator according to claim 13, further comprising electromagnetic means for floating the reaction mass relative to the vibrating structure.

Claim 23

Dependent Claim 178 words

System for actively controlling structure borne noise and vibration comprising at least one bidirectional variable reluctance actuator acting between a vibrating structure and a reaction mass, and a force control means for controlling the forces applied to said vibrating structure; wherein each said bidirectional variable reluctance actuator comprises a pair of electromagnets physically connected together through a common structural element and at least one armature disposed between the pair of electromagnets, each of the electromagnets being constructed and arranged relative to said armature in a manner causing the electromagnets to act on said armature with oppositely directed forces; and wherein said force control means comprises a flux linkage control means for controlling the electromagnetic forces applied to the armature of each actuator by the electromagnets thereof in a manner producing a relationship between a net force produced on said armature by said electromagnets and an applied reference signal which is substantially linear throughout the range of motion of the armature, and means for producing said reference signal as a function of the vibration experienced by said vibrating structure.

Claim 24

Dependent Claim 178 words

System for actively controlling structure borne noise and vibration comprising at least one bidirectional variable reluctance actuator acting between a vibrating structure and a reaction mass, and a force control means for controlling the forces applied to said vibrating structure; wherein each said bidirectional variable reluctance actuator comprises a pair of electromagnets physically connected together through a common structural element and at least one armature disposed between the pair of electromagnets, each of the electromagnets being constructed and arranged relative to said armature in a manner causing the electromagnets to act on said armature with oppositely directed forces; and wherein said force control means comprises a flux linkage control means for controlling the electromagnetic forces applied to the armature of each actuator by the electromagnets thereof in a manner producing a relationship between a net force produced on said armature by said electromagnets and an applied reference signal which is substantially linear throughout the range of motion of the armature, and means for producing said reference signal as a function of the vibration experienced by said vibrating structure.

Claim 25

Dependent Claim 39 words

System for actively controlling structure borne noise and vibration according to claim 22, wherein said means for producing said vibration signal as a function of the vibration experienced by the vibrating structure includes sensor means for sensing said vibration.

Claim 26

Dependent Claim 22 words

System for actively controlling structure borne noise and vibration according to claim 23, wherein said sensor means comprises at least one accelerometer.

Claim 27

Dependent Claim 41 words

System for actively controlling structure borne noise and vibration according to claim 24, wherein said vibrating structure is a rotary shaft, and wherein said means for producing further comprises pulse tachometer means for providing a signal representative of shaft rotational speed.

Claim 28

Dependent Claim 138 words

System for actively controlling structure borne noise and vibration according to claim 25, wherein, for cancelling thrust vibrations, said accelerometer is connected to a thrust block of a thrust bearing of the rotary shaft; wherein a thrust collar is mounted about said shaft and an annular reaction mass is floated about said thrust collar; wherein one of the armatures and the electromagnets of said actuator is carried by said reaction mass and the other thereof is carried by said thrust collar; and wherein said force control means includes means for carrying out on-line Fourier analysis of an acceleration signal from said accelerometer at a frequency determined by the signal from the tachometer, and adaptive control means for carrying out an optimization routine which acts to null out the thrust vibrations by adjusting the power supplied to the electromagnets.

Claim 29

Dependent Claim 186 words

System for actively controlling structure borne noise and vibration according to claim 25, wherein, for torsional damping and oscillatory torque cancellation, said accelerometer is connected to the shaft; wherein a disk is fixedly mounted on the rotary shaft; wherein an annular reaction mass in the form of an inertia ring is floated about said disk and a plurality of said bidirectional variable reluctance actuators are mounted therebetween; wherein the actuator electromagnets are mounted in pairs on one of said disk and said inertia ring, and the armatures are mounted on the other of said disk and said inertia ring, the electromagnets of each pair being arranged to exert oppositely directed forces on a respective armature in a circumferential direction relative to the inertia ring and the rotary shaft; and wherein said force linkage control means includes means for carrying out on-line Fourier analysis of an acceleration signal from said accelerometer at a frequency determined by the signal from the tachometer, and adaptive control means for carrying out an optimization routine which acts to null out the torque vibrations by adjusting the power supplied to the electromagnets.

Claim 30

Dependent Claim 161 words

System for actively controlling structure borne noise and vibration according to claim 25, wherein a plurality of said bidirectional variable reluctance actuators are provided for cancelling radial vibrations; wherein said accelerometer is connected to a bearing housing of the rotary shaft; wherein the armatures of the actuators are integrated into an armature ring that is mounted around the rotary shaft for rotation therewith; wherein an annular reaction mass is floated about said armature ring; wherein the electromagnets of said actuators are carried by said reaction mass and are arranged in diametrally opposed pairs which act on the armature ring in radially opposite directions; and wherein said force linkage control means includes means for carrying out on-line Fourier analysis of an acceleration signal from said accelerometer at a frequency determined by the signal from the tachometer, and adaptive control means for carrying out an optimization routine which acts to null out the thrust vibrations by adjusting the power supplied to the electromagnets.

Claim 31

Dependent Claim 80 words

System for actively controlling structure borne noise and vibration according to claim 28, wherein, for cancelling thrust vibrations, said accelerometer is connected to a thrust block of a thrust bearing of the rotary shaft; wherein said armature ring comprises a thrust collar mounted about said shaft and an annular reaction mass is floated about said thrust collar; and wherein at least a further pair of electromagnets is disposed on said reaction mass on axially opposite sides of the armature ring.

Claim 32

Dependent Claim 156 words

System for actively controlling structure borne noise and vibration according to claim 24, wherein a plurality of said bidirectional variable reluctance actuators are provided for cancelling lateral vibrations at nonrotary vibrating structures, said system further comprising means for mounting one of the armatures and the electromagnets of the actuators to the nonrotary vibrating structure, the other of said armatures and electromagnets being integrated into the reaction mass; wherein said electromagnets are disposed relative to said armatures for producing opposite laterally acting forces on the reaction mass, the reaction mass being floated relative to said means for mounting so as to be freely movable in directions of action of said laterally acting forces; wherein the accelerometer is mounted to said means for mounting; and wherein said force linkage control means includes an adaptive control means for carrying out an optimization routine which acts to null out the torque vibrations by adjusting the power supplied to the electromagnets.

Claim 33

Dependent Claim 26 words

System for actively controlling structure borne noise and vibration according to claim 30, wherein said means for floating comprises hydrostatic means for floating the reaction mass.

Claim 34

Dependent Claim 31 words

System for actively controlling structure borne noise and vibration according to claim 30, wherein said means for floating comprises electromagnetic means for floating the reaction mass relative to the vibrating structure.

Claim 35

Dependent Claim 22 words

System for actively controlling structure borne noise and vibration according to claim 30, wherein said nonrotary vibrating structure is a bearing housing.

Claim 36

Dependent Claim 69 words

System for actively controlling structure borne noise and vibration according to claim 22, wherein a plurality of said bidirectional variable reluctance actuators is provided for cancelling vibration in up to six degrees of freedom, said plurality of actuators forming plural actuator units, each of which comprises bidirectional axially acting actuators and bidirectional tangentially acting actuators, said actuator units being uniformly distributed about a cross section of the vibrating structure.

Claim 37

Dependent Claim 82 words

System for actively controlling structure borne noise and vibration according to claim 34, wherein means for mounting said actuator units to the vibrating structure is provided, one of the electromagnets and the armatures of each of said axially acting and tangentially acting actuators being rigidly supported on said means for mounting, and the other of said electromagnets and armatures of each of said actuators being incorporated with the reaction mass and suspended in floating relation with respect to the means for mounting.

Claim 38

Dependent Claim 22 words

System for actively controlling structure borne noise and vibration according to claim 34, wherein said means for mounting comprises a pipe clamp.

Claim 39

Dependent Claim 35 words

System for actively controlling structure borne noise and vibration according to claim 36, wherein said vibrating structure is a steam pipe of a steam turbine and said pipe clamp is mounted about said steam pipe.

Claim 40

Dependent Claim 38 words

System for actively controlling structure borne noise and vibration according to claim 34, wherein said flux control system comprises a position measuring system connected to the reaction mass, and a velocity measuring system connected to the vibrating structure.

Claim 41

Dependent Claim 185 words

System for actively controlling structure borne noise and vibration according to claim 38, wherein said flux control system further comprises a quiescent position controller connected to the output of said position measuring system, a nulling system, a sine/cosine generator, and a reference force generator means for producing a reference force signal f k of the form: a.sub.kn cos nwt+b.sub.kn sin nwt where a kn and b kn are weighting coefficients produced by the nulling system, n corresponds to the various harmonics, k corresponds to a velocity output of the velocity measuring system, and cos nwt and sin nwt are functions of an output of a sine/cosine generator; wherein said nulling system receiving signals from a harmonic analyser which is connected to an output of said sine/cosine generator and to an output of said velocity measuring system; and wherein a force controller means for controlling the power delivered to coils of said electromagnets responds to signals from a force coordinate transformer that is controlled by a signal which is a function of the output of said reference force generator means and of said quiescent position controller.

Claim 42

Dependent Claim 52 words

System for actively controlling structure borne noise and vibration according to claim 39, wherein an output of said velocity measuring system is connected to an active damping system, and wherein the signal by which the force coordinate controller is controlled is also a function of the output of said active damping system.

Claim 43

Dependent Claim 184 words

System for actively controlling structure borne noise and vibration according to claim 22, wherein said flux control system further comprises a quiescent position controller connected to the output of said position measuring system, a nulling system, a sine/cosine generator, and a reference force generator means for producing a reference force signal f k of the form: a.sub.kn cos nwt+b.sub.kn sin nwt where a kn and b kn are weighting coefficients produced by the nulling system, n corresponds to the various harmonics, k corresponds to a velocity output of the velocity measuring system, and cos nwt and sin nwt are functions of an output of a sine/cosine generator; wherein said nulling system receives signals from a harmonic analyser which is connected to an output of said sine/cosine generator and to an output of said velocity measuring system; and wherein force controller means for controlling the power delivered to coils of said electromagnets responds to signals from a force coordinate transformer that is controlled by a signal which is a function of the output of said reference force generator means and of said quiescent position controller.

Claim 44

Dependent Claim 52 words

System for actively controlling structure borne noise and vibration according to claim 41, wherein an output of said velocity measuring system is connected to an active damping system, and wherein the signal by which the force coordinate controller is controlled is also a function of the output of said active damping system.

Claim 45

Dependent Claim 37 words

System for actively controlling structure borne noise and vibration according to claim 42, wherein said velocity measuring system comprises sensor means for producing an output signal as a function of the vibration experienced by the vibrating structure.

Claim 46

Dependent Claim 22 words

System for actively controlling structure borne noise and vibration according to claim 43, wherein said sensor means comprises at least one accelerometer.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1995-06-30	1995-12-30	1996-06-30	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1999-06-30	1999-12-30	2000-06-30	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2003-06-30	2003-12-30	2004-06-30	$7700.00	Window Closed / Lapsed

Bidirectional variable reluctance actuator and system for active attenuation of vibration and structure borne noise utilizing same

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