US5000415A — Active vibration isolation systems

Claim 1

Independent Claim 69 words

In a method of isolating a load from a source of vibrations, the improvement comprising in combination the steps of: detecting vibrations from said source; providing a displacement transducer stage for compensating said vibrations for said load; providing a feedforward loop; controlling said displacement transducer stage with said detected vibrations through said feedforward loop; and increasing isolation with a resilient mount between said displacement transducer stage and said load.

Claim 2

Dependent Claim 69 words

In a method of isolating a load from a source of vibrations, the improvement comprising in combination the steps of: detecting vibrations from said source; providing a displacement transducer stage for compensating said vibrations for said load; providing a feedforward loop; controlling said displacement transducer stage with said detected vibrations through said feedforward loop; and increasing isolation with a resilient mount between said displacement transducer stage and said load.

Claim 3

Dependent Claim 36 words

A method as in claim 1, including the steps of: detecting residual movements of the load; providing a feedback loop; and controlling said displacement transducer stage additionally with said detected residual movements through said feedback loop.

Claim 4

Dependent Claim 30 words

A method as in claim 2, including the step of: supporting said load relative to said source of vibrations with said displacement transducer stage and said resilient mount in series.

Claim 5

Dependent Claim 30 words

A method as in claim 1, including the step of: supporting said load relative to said source of vibrations with said displacement transducer stage and said resilient mount in series.

Claim 6

Dependent Claim 71 words

A method as in claim 1, including the steps of: using in said displacement transducer stage a piezoelectric transducer of an inherently non-linear voltage-displacement characteristic; providing a first feedback signal proportional to the electric charge on the piezoelectric displacement transducer; providing a second feedback signal proportional to the voltage on the piezoelectric displacement transducer; and linearizing the voltage-displacement characteristic of said piezoelectric displacement transducer with said first and second feedback signals.

Claim 7

Dependent Claim 31 words

A method as in claim 1, wherein: said vibrations are detected in three orthogonally related directions; and said transducer stage compensates said vibrations for said load in three othogonally related directions.

Claim 8

Dependent Claim 44 words

A method as in claim 6, wherein: residual movements of said load are detected in three orthogonally related directions; and said displacement transducer stage is controlled additionally in three orthogonally related directions in response to said residual movements detected in three orthogonally related directions.

Claim 9

Dependent Claim 51 words

A method as in claim 1, including the steps of: providing said feedforward loop with an adjustable gain; detecting residual movements of the load; comparing phases of signals representing said detected vibrations and signals representing said detected residual movements; and varying said adjustable gain in response to said comparing of phases.

Claim 10

Dependent Claim 30 words

A method as in claim 8, including the steps of: providing a feedback loop; and controlling said displacement transducer stage additionally with said detected residual movements through said feedback loop.

Claim 11

Dependent Claim 65 words

A method as in claim 1, including the steps of: providing said feedforward loop with an adjustable gain; detecting residual movements of the load; comparing phases of signals representing said detected vibrations and signals representing said detected residual movements; and adjusting said gain in response to a change in phase between said signals representing said detected vibrations and said signals representing said detected residual movements.

Claim 12

Dependent Claim 30 words

A method as in claim 10, including the steps of: providing a feedback loop; and controlling said displacement transducer stage additionally with said detected residual movements through said feedback loop.

Claim 13

Independent Claim 65 words

A method of linearizing performance of a piezoelectric displacement transducer, comprising the steps of: energizing said piezoelectric displacement transducer; providing a first feedback signal proportional to the electric charge on the piezoelectric displacement transducer; providing a second feedback signal proportional to the voltage on the piezoelectric displacement transducer; and linearizing the voltage-displacement characteristic of said piezoelectric displacement transducer with said first and second feedback signals.

Claim 14

Independent Claim 65 words

A method of linearizing performance of a piezoelectric displacement transducer, comprising the steps of: energizing said piezoelectric displacement transducer; providing a first feedback signal proportional to the electric charge on the piezoelectric displacement transducer; providing a second feedback signal proportional to the voltage on the piezoelectric displacement transducer; and linearizing the voltage-displacement characteristic of said piezoelectric displacement transducer with said first and second feedback signals.

Claim 15

Dependent Claim 68 words

An active vibration isolator for isolating a load from a source of vibrations, comprising in combination: a base; a resilient mount for said load; and a feedforward vibration isolation apparatus including a vibration detector stage adapted to be coupled to said source of vibrations, a displacement transducer stage between said base and said resilient mount, and feedforward loop including said vibration detector stage and said displacement transducer stage.

Claim 16

Dependent Claim 68 words

An active vibration isolator for isolating a load from a source of vibrations, comprising in combination: a base; a resilient mount for said load; and a feedforward vibration isolation apparatus including a vibration detector stage adapted to be coupled to said source of vibrations, a displacement transducer stage between said base and said resilient mount, and feedforward loop including said vibration detector stage and said displacement transducer stage.

Claim 17

Dependent Claim 33 words

An active vibration isolator as in claim 13, wherein: said displacement transducer stage and said resilient mount are part of a support of said load between said source of vibrations and said load.

Claim 18

Dependent Claim 38 words

An active vibration isolator as in claim 13, wherein: said vibration detector stage includes three orthogonally sensitive vibration detectors; and said displacement transducer stage includes three orthogonally active displacement transducers in feedforward loop relationship with said vibration detectors.

Claim 19

Dependent Claim 33 words

An active vibration isolator as in claim 13, including: three orthogonally sensitive movement detectors adapted to be coupled to said load; and feedback loop means including said movement detectors and said displacement transducers.

Claim 20

Dependent Claim 93 words

An active vibration isolator as in claim 13, wherein: said displacement transducer stage includes a piezoelectric displacement transducer of an inherently non-linear voltage-displacement characteristic; and said vibration isolator includes: means coupled to said piezoelectric displacement transducer for providing a first feedback signal proportional to the electric charge on the piezoelectric displacement transducer; means coupled to said piezoelectric displacement transducer for providing a second feedback signal proportional to the voltage on the piezoelectric displacement transducer; and means for linearizing the voltage-displacement characteristic of said piezoelectric displacement transducer with said first and second feedback signals.

Claim 21

Dependent Claim 74 words

An active vibration isolator as in claim 13, wherein: said displacement transducer stage includes a piezoelectric displacement transducer of an inherently non-linear voltage-displacement characteristic; and said vibration isolator includes: amplifier means for driving said piezoelectric displacement transducer through an amplifier output; a capacitor in series with said piezoelectric displacement transducer; a first feedback loop between said capacitor and an amplifier input; and a second feedback loop between said amplifier output and said amplifier input.

Claim 22

Dependent Claim 36 words

An active vibration isolator as in claim 13, including: a residual movement detector stage adapted to be coupled to said load; and a feedback loop including said residual movement detector stage and said displacement transducer stage.

Claim 23

Dependent Claim 33 words

An active vibration isolator as in claim 19, wherein: said displacement transducer stage and said resilient mount are part of a support of said load between said source of vibrations and said load.

Claim 24

Dependent Claim 40 words

An active vibration isolator as in claim 13, wherein: said displacement transducer stage includes a tripod structure having three legs equipped with three displacement transducers and having a tripod head coupled to a thrust plate for displacement of said load.

Claim 25

Dependent Claim 18 words

An active vibration isolator as in claim 21, wherein: said resilient mount is attached to said thrust plate.

Claim 26

Dependent Claim 73 words

An active vibration isolator as in claim 13, wherein: said feedforward loop has an adjustable gain; and said vibration isolator includes a residual movement detector stage adapted to be coupled to said load, means for comparing phases of signals representing vibrations detected by said vibration detector stage and signals representing residual movements detected by said residual movement detector stage, and means for varying said adjustable gain in response to said comparing of phases.

Claim 27

Dependent Claim 40 words

An active vibration isolator as in claim 23, wherein: said means for varying said adjustable gain include means for adjusting said gain in response to a change in phase between said signals representing vibrations and said signals representing residual movement.

Claim 28

Dependent Claim 23 words

An active vibration isolator as in claim 23, including: a feedback loop including said residual movement detector stage and said displacement transducer stage.

Claim 29

Dependent Claim 81 words

A displacement transducer stage, comprising in combination: a piezoelectric displacement transducer of an inherently non-linear voltage-displacement charactertistic; means coupled to said piezoelectric displacement transducer for providing a first feedback signal proportional to the electric charge on the piezoelectric displacement transducer; means coupled to said piezoelectric displacement transducer for providing a second feedback signal proportional to the voltage on the piezoelectric displacement transducer; and means for linearizing the voltage-displacment characteristic of said piezoelectric displacement transducer with said first and second feedback signals.

Claim 30

Dependent Claim 81 words

A displacement transducer stage, comprising in combination: a piezoelectric displacement transducer of an inherently non-linear voltage-displacement charactertistic; means coupled to said piezoelectric displacement transducer for providing a first feedback signal proportional to the electric charge on the piezoelectric displacement transducer; means coupled to said piezoelectric displacement transducer for providing a second feedback signal proportional to the voltage on the piezoelectric displacement transducer; and means for linearizing the voltage-displacment characteristic of said piezoelectric displacement transducer with said first and second feedback signals.

Claim 31

Dependent Claim 81 words

A displacement transducer stage as in claim 26, wherein: said means for linearizing said voltage-displacement characteristic include amplifier means for driving said piezoelectric displacement transducer through an amplifier output and a capacitor in series with said piezoelectric displacement transducer; said means for providing a first feedback signal including a first feedback loop between said capacitor and an amplifier input; and said means for providing a second feedback signal including a second feedback loop between said amplifier output and said amplifier input.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1994-03-18	1994-09-17	1995-03-19	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1998-03-18	1998-09-17	1999-03-19	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2002-03-18	2002-09-17	2003-03-19	$7700.00	Window Closed / Lapsed

Active vibration isolation systems

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