WO1986001887A1 - Elements de commande a longueur de parcours stable - Google Patents

Elements de commande a longueur de parcours stable Download PDF

Info

Publication number
WO1986001887A1
WO1986001887A1 PCT/US1985/001705 US8501705W WO8601887A1 WO 1986001887 A1 WO1986001887 A1 WO 1986001887A1 US 8501705 W US8501705 W US 8501705W WO 8601887 A1 WO8601887 A1 WO 8601887A1
Authority
WO
WIPO (PCT)
Prior art keywords
transducer
driver plate
driver
piezoelectric
central post
Prior art date
Application number
PCT/US1985/001705
Other languages
English (en)
Inventor
Theodore A. Toth
Original Assignee
Honeywell Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Honeywell Inc. filed Critical Honeywell Inc.
Publication of WO1986001887A1 publication Critical patent/WO1986001887A1/fr

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C19/00—Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
    • G01C19/58—Turn-sensitive devices without moving masses
    • G01C19/64—Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams
    • G01C19/66—Ring laser gyrometers
    • G01C19/661—Ring laser gyrometers details
    • G01C19/665—Ring laser gyrometers details control of the cavity
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/08—Construction or shape of optical resonators or components thereof
    • H01S3/081—Construction or shape of optical resonators or components thereof comprising three or more reflectors
    • H01S3/083—Ring lasers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/20—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators
    • H10N30/204—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators using bending displacement, e.g. unimorph, bimorph or multimorph cantilever or membrane benders
    • H10N30/2047—Membrane type

Definitions

  • the present invention relates to ring laser gyroscopes. More particularly, it relates to a path length control element for the cavity of a ring laser gyroscope.
  • a ring laser gyroscope is basically a laser apparatus having a ring type resonant cavity, typically triangular in configuration.
  • the laser beam is directed around the triangular path by suitable mirrors positioned at each of the corners of the triangular structure. In most cases there are two laser beams traveling in opposite directions relative to each other around the ring.
  • the positioning of the mirrors in the corners of the ring, or triangle not only direct the laser beams down the channels of " the resonant cavity but also determine the path length of the resonant cavity.
  • the path length of the resonant cavity must be maintained at an integral number of wave lengths of the laser beam.
  • the block defining the resonant cavity for the ring laser is made of a substance having a low thermal coefficient of expansion such as Cervit. While the
  • Patent 4,383,763, issued to Hutchings et al there is shown and claimed a structure specifically arranged to eliminate the undesired rotational movement of the mirror and which shows a driving number comprised of a pair of piezoelectric discs sandwiched about a metallic membrane.
  • An adjustable screw provides an adjustable thrust bearing.
  • an object of the present invention to provide an improved piezoelectric driver element which exhibits improved characteristics over an extremely wide range of temperature variations. It is another object of the present invention to provide an improved piezoelectric driver element as set forth which is suitable for use in a path length controller for ring laser gyro assembly.
  • a piezoelectric driver assembly which includes piezoelectric discs bonded on opposite sides of a driver diaphragm.
  • the driver diaphragm, or plate is made of the same ceramic material ' such as Cervit as the main transducer block resulting in no thermal stresses between the driving diaphragm and the transducer.
  • the bonding of the piezoelectric ceramic discs to the ceramic driver diaphragm introduces little to no thermal stress between the piezoelectric discs and the driver diaphragm, or plate, bonded to the transducer block, there is no interfacing metallic structure such as a adjusting screw to interpose a thermal response difference producing a scale factor shift.
  • Figure 1 is a schematic block diagram of a ring laser gyro system embodying the present invention
  • Figure 2 is a cross-sectional view of a prior art structure over which the present invention is an improvement
  • Figure 3 is a cross-sectional view of a piezoelectric driver assembly embodying the present invention.
  • Figure 1 a schematic diagram of a ring laser gyro embodying the present invention.
  • the apparatus is represented as a main block 2 which is shown as being triangular in shape.
  • the main block 2 is formed of a glass-like substance having a relatively low thermal coefficient of expansion, such as Cervit or Zerodur.
  • the block has formed therein a cavity 4 defining a triangular path and which is preferably filled with a lasing gas such as the traditional helium-neon mixture.
  • a pair of counter-rotating laser beams 6 are introduced into the cavity 4 and travel in opposite directions about the triangular path defined by the cavity 4.
  • reflecting means or mirror assemblies 8, 10, and 12, respectively At each of the corners of the block 2 and facing into the cavity 4, there is positioned reflecting means or mirror assemblies 8, 10, and 12, respectively.
  • the mirror assembly 12 is illustrated as being associated with detector 14. In that respect, the mirror assembly 12 is, in effect, a beam splitter. That is, a portion of the laser beams 6 are
  • the detector means 14 is shown merely as a block. The details thereof are not essential to the present invention. It might be pointed out, however, that there are two aspects of detector means 14. First, the detector 14 detects differences in the frequency of the two counter-rotating beams as a function of the physical rotation of the ring laser gyro assembly. The detector 14 also responds to changes in the magnitude, of the laser signals which are indicative of changes in the path length of the resonant cavity, effectively detuning the cavity.
  • the driver 20 is secured to and drives the transducer structure forming a part of the mirror assembly 10.
  • the detector 14 will produce an output signal indicative of the amount of that shift. That signal is applied by means of the feedback path 16 to the voltage source 18 causing the driver 20 to be moved, in response thereto, in a direction and in an amount to tend to restore the resonant cavity path length to its original position.
  • the mirror or reflector 8 may be either a simple reflecting mirror or may be a duplicate of the adjustable mirror 10.
  • a transducer assembly of a type heretofore used in a ring laser gyro for the purpose of controlling the path length of the resonant cavity.
  • a transducer body 22 is formed of a material such as the hereinabove referenced Cervit or Zerodur.
  • the body.22 - is configured with a central post 24 of substantial dimension and an outer wall member 26 is in the form of an annulus.
  • the central post 24 and the outer wall 26 are connected by a first and second relatively thin diaphragm or membrane 28 and 30, respectively, with the central post 24 and the outer wall 26 extending somewhat beyond of the surface of the membrane 30.
  • the body 22 includes a transverse hole 32 which extends through the side wall structure 26 and the center post 24 at a position between the two membranes 28 and 20.
  • a metallic pin 34 is inserted into the transverse hole 32.
  • the pin 34 has a threaded hole therethrough which is positioned in
  • the pin 34 comprises a nut captive for a screw 38.
  • a driver element 40 is secured to the transducer body 22 by means of the screw 38.
  • the driver element 40 includes a first and second piezoelectric ceramic disc 42 and 44, respectively, which are bonded together with a conductive coating 46 there between.
  • the piezoelectric ceramic disc 44 is, in turn, bonded conductively to one surface of a metallic disc armature of driver plate 48.
  • This disc 48 is preferably made of a metallic alloy having a low coefficient of thermal expansion such as Kovar.
  • the disc 48 has a peripheral rim which is held in firm engagement with the upper surface of the transducer body 22 by means of the screw 38.
  • a metallic electrode 50 is deposited on the upper surface of the piezoelectric disc 42.
  • the screw 38 is tightened in the nut 34 to securely hold the driver element 40 on the transducer body 22.
  • the tightening of the screw 38 also established a predetermined preload condition on the transducer assembly.
  • the leads 52 and 54 from the regulated voltage sources 18 are connected to the electrodes of the piezoelectric ceramic discs 42 and 44.
  • the lead 52 is* connected to the two outermost
  • the mirror 56 comprises the positionally adjustable reflecting means represented by the mirror assembly 10 of Figure 1.
  • the structure shown in Figure 2 has a disadvantage, comparable to that of the structures shown in Patent 4,383,763, in that the scale factor of the transducer assembly is initially set by the adjustment of the screw 38 relative to the pin-nut 34. In the extremes of temperature to which such devices must be exposed, the thermal expansion of the adjusting screw 38 would tend to cause a shift in the scale factor of the adjusting circuitry.
  • the transducer body 58 is identical or substantially identical to the transducer body 22 as shown in Figure 2. Although the transducer body 58 may be identical to the transducer body 22, it may differ in that there is no necessity for the transverse hole 32 or the axial hole 36. As before, the transducer body 58 includes a central post 60 and an outer wall 62 of relatively substantial thickness dimensions. The outer wall 62 and the central post 60 are connected together by a first and a second relatively thin membrane member 64 and 66, respectively. The first membrane 64 defines a planar surface with the associated end of the post 60 and the wall 62. A mirror 68 is affixed to the remote end of the center post 60 opposite from the planar surface.
  • the driver assembly 70 includes an armature or driver plate 72 which is preferably formed of the same material, i.e. Cervit, as the transducer body 58.
  • the armature or driver plate 72 is in the form of a disc having a relatively thick peripheral rim 74, a central hub 76 and a relatively thin membrane 78 interconnecting the rim 74 and the hub 76.
  • One surface of the membrane may be coplanar with the upper surface of the hub 76.
  • the other surface of the hub 76 is coplanar with the corresponding surface of the rim 74.
  • the surface of the membrane 78 defines an annular recess.
  • a first annular ceramic piezoelectric element is positioned in the recess defined by the configuration of the plate 72.
  • a second annular ceramic piezoelectric element 82 is positioned on the opposite side of the membrane 78 from the element 80.
  • the elements 80 and 82 were made of piezoelectric material.
  • the opposite faces of each of the piezoelectric elements 80 and 82 are provided with an electrically conductive coating which may be in the form of a very thin metallic film deposited thereon. These electrically conductive surfaces will, as will be seen hereinafter, constitute electrodes for the exitation of the piezoelectric elements.
  • the two piezoelectric elements 80 and 82 are securely bonded, respectively, to the opposite faces of the membrane 78 of the armature or driver plate 72.
  • One surface of the peripheral rim 74 of the driver plate 72 is securely bonded, as by optical bonding or by epoxy cement, to the planar surface of the transducer body 58 at the surface of the end wall 62.
  • the coplanar surface of the hub 76 is bonded to the planar surface of the block 58 in the position of the proximate end the center post 60.
  • the detector 14 In a response to a detected change in the path length of the resonant cavity, the detector 14, as previously mentioned, applies a control signal to the regulated voltage source 18. This unit, in turn.
  • the transducer body 58 was constructed of material such as Cervit and the armature or driver plate was formed of a metal such as Kovar; in the present invention, the driver plate 72 is formed of the same materials, such as Cervit, as the transducer body 58. With both the driver plate 72 and the transducer body 58 being made of the same material, they will have
  • the driver plate 72 may be bonded securely to the surface of the transducer body 58 without introducing thermal stresses at the interfaces thereof.
  • the driver plate was secured to the transducer body by means of a metal screw and nut arrangement
  • the apparatus in accordance with the present invention there is no metallic interconnection between the driver plate and the transducer body, the transducer plate being securely bonded to .the transducer body at . the periphery and at the central post/hub interface.
  • the metallic interconnection introduces a difference in thermal response characteristics between the metal and the glass-like substance of the transducer body. This difference in temperature response characteristics introduces instabilities in the scale factor of the correcting circuitry at the extremely wide temperature range to which the apparatus is subjected.
  • an improved piezoelectric transducer apparatus especially useful in the correcting of the path lengths of a ring laser gyro.
  • the improved structure is characterized in the greater stability of the scale factor of the correcting circuitry as well as a reduction in thermal stresses when apparatus is subjected to a variation in temperatures ranging from -65 to +180 degrees Fahrenheit.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Electromagnetism (AREA)
  • Optics & Photonics (AREA)
  • Plasma & Fusion (AREA)
  • Power Engineering (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Gyroscopes (AREA)

Abstract

Un ensemble d'entraînement piézoélectrique (70) comprend des disques piézoélectriques (86, 82) liés aux côtés opposés d'un diaphragme d'entraînement (72). Le diaphragme d'entraînement (72) ou plaque est constitué du même matériau céramique, tel que le Cervit, que le bloc transducteur principal (58). Le diaphragme (72) est lié au bloc transducteur (58) sans créer de contraintes thermiques entre le diaphragme d'entraînement (72) et le bloc transducteur (58).
PCT/US1985/001705 1984-09-14 1985-09-09 Elements de commande a longueur de parcours stable WO1986001887A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US65073384A 1984-09-14 1984-09-14
US650,733 1984-09-14

Publications (1)

Publication Number Publication Date
WO1986001887A1 true WO1986001887A1 (fr) 1986-03-27

Family

ID=24610067

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1985/001705 WO1986001887A1 (fr) 1984-09-14 1985-09-09 Elements de commande a longueur de parcours stable

Country Status (2)

Country Link
EP (1) EP0194301A1 (fr)
WO (1) WO1986001887A1 (fr)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2611038A1 (fr) * 1987-02-18 1988-08-19 Salaberry Bernard De Gyrometre laser, dispositif d'elimination des rotations parasites des miroirs piezoelectriques
FR2611039A1 (fr) * 1987-02-18 1988-08-19 Salaberry Bernard De Gyrometre laser, dispositif de suppression des rotations parasites des miroirs mobiles
WO1988006275A2 (fr) * 1987-02-18 1988-08-25 Salaberry Bernard Lucien Charl Gyrometre laser, dispositif d'elimination des rotations parasites des miroirs piezoelectriques
EP0331581A1 (fr) * 1988-03-04 1989-09-06 SEXTANT Avionique Miroir piézoélectrique pour gyromètre à laser
FR2630551A1 (fr) * 1988-04-21 1989-10-27 Salaberry Bernard De Miroir piezoelectrique compense pour gyrometre a laser
FR2663735A1 (fr) * 1990-04-19 1991-12-27 Litton Systems Inc Dispositif de regulation de longueur de parcours pour gyrolasers et ces gyrolasers.
FR2670622A1 (fr) * 1990-12-18 1992-06-19 Raytheon Co Dispositif de montage de miroir dans un laser.
EP0512265A1 (fr) * 1991-04-09 1992-11-11 Honeywell Inc. Dispositif de déplacement d'un mirroir
WO1995033182A1 (fr) * 1994-05-27 1995-12-07 Honeywell Inc. Systeme de commande de puissance pour gyrometre laser pilote par microprocesseur
EP2873949A3 (fr) * 2013-11-14 2015-06-10 Honeywell International Inc. Vis à filetage minimal pour réduire les décalages d'alignement
CN115326045A (zh) * 2022-10-14 2022-11-11 天津集智航宇科技有限公司 一种激光陀螺的稳频机构

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4160184A (en) * 1978-01-09 1979-07-03 The Singer Company Piezoelectric actuator for a ring laser
GB2104283A (en) * 1981-07-24 1983-03-02 Litton Systems Inc Piezoelectric transducer
US4383763A (en) * 1979-09-12 1983-05-17 Litton Systems, Inc. Controllable mirrors

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4160184A (en) * 1978-01-09 1979-07-03 The Singer Company Piezoelectric actuator for a ring laser
US4383763A (en) * 1979-09-12 1983-05-17 Litton Systems, Inc. Controllable mirrors
GB2104283A (en) * 1981-07-24 1983-03-02 Litton Systems Inc Piezoelectric transducer

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2611038A1 (fr) * 1987-02-18 1988-08-19 Salaberry Bernard De Gyrometre laser, dispositif d'elimination des rotations parasites des miroirs piezoelectriques
FR2611039A1 (fr) * 1987-02-18 1988-08-19 Salaberry Bernard De Gyrometre laser, dispositif de suppression des rotations parasites des miroirs mobiles
WO1988006276A2 (fr) * 1987-02-18 1988-08-25 Salaberry Bernard Lucien Charl Gyrometre laser, dispositif de suppression des rotations parasites des miroirs mobiles
WO1988006275A2 (fr) * 1987-02-18 1988-08-25 Salaberry Bernard Lucien Charl Gyrometre laser, dispositif d'elimination des rotations parasites des miroirs piezoelectriques
WO1988006276A3 (fr) * 1987-02-18 1988-12-29 Salaberry Bernard Lucien Charl Gyrometre laser, dispositif de suppression des rotations parasites des miroirs mobiles
WO1988006275A3 (fr) * 1987-02-18 1988-12-29 Salaberry Bernard Lucien Charl Gyrometre laser, dispositif d'elimination des rotations parasites des miroirs piezoelectriques
EP0331581A1 (fr) * 1988-03-04 1989-09-06 SEXTANT Avionique Miroir piézoélectrique pour gyromètre à laser
FR2628201A1 (fr) * 1988-03-04 1989-09-08 Sfena Miroir piezoelectrique pour gyrometre a laser
FR2630551A1 (fr) * 1988-04-21 1989-10-27 Salaberry Bernard De Miroir piezoelectrique compense pour gyrometre a laser
WO1989010539A1 (fr) * 1988-04-21 1989-11-02 Salaberry Bernard Lucien Charl Miroir piezoelectrique compense pour gyrometre a laser
FR2663735A1 (fr) * 1990-04-19 1991-12-27 Litton Systems Inc Dispositif de regulation de longueur de parcours pour gyrolasers et ces gyrolasers.
FR2670622A1 (fr) * 1990-12-18 1992-06-19 Raytheon Co Dispositif de montage de miroir dans un laser.
GB2251120A (en) * 1990-12-18 1992-06-24 Raytheon Co Passive pathlength control mirror for laser
GB2251120B (en) * 1990-12-18 1995-05-10 Raytheon Co Passive pathlength control mirror for laser
EP0512265A1 (fr) * 1991-04-09 1992-11-11 Honeywell Inc. Dispositif de déplacement d'un mirroir
WO1995033182A1 (fr) * 1994-05-27 1995-12-07 Honeywell Inc. Systeme de commande de puissance pour gyrometre laser pilote par microprocesseur
EP2873949A3 (fr) * 2013-11-14 2015-06-10 Honeywell International Inc. Vis à filetage minimal pour réduire les décalages d'alignement
CN115326045A (zh) * 2022-10-14 2022-11-11 天津集智航宇科技有限公司 一种激光陀螺的稳频机构

Also Published As

Publication number Publication date
EP0194301A1 (fr) 1986-09-17

Similar Documents

Publication Publication Date Title
US4383763A (en) Controllable mirrors
US4160184A (en) Piezoelectric actuator for a ring laser
US4267478A (en) Pathlength controller for a ring laser gyroscope
US4691323A (en) Path length controller for ring laser gyroscope
CA1162281A (fr) Miroir reglable
WO1986001887A1 (fr) Elements de commande a longueur de parcours stable
US4386853A (en) Bending actuator for ring laser gyroscope
JPH0142153B2 (fr)
US5148076A (en) Apparatus for thermal tuning of path length control drivers
US4628515A (en) Ring laser, especially for a ring laser type of gyro
US4815321A (en) Movement sensing
US4817112A (en) Low cost ring laser angular rate sensor
US5162870A (en) Substrate for ring laser gyro with nonuniform outer rim
US5311280A (en) Laser light length control assembly for ring laser gyro
US4565941A (en) Oscillatory drive mechanisms for a ring laser gyro
US4824253A (en) Glass driver for laser mirror
US5116131A (en) Mirror transducer assembly for ring laser gyroscopes
US5116128A (en) Mirror transducer assembly for ring laser gyroscope
US4727638A (en) Low cost ring laser angular rate sensor
US4836677A (en) Ring laser cavity length control mirror assembly
US5420685A (en) Electrostatic path length control transducer
EP0293528A1 (fr) Dispositif de commande de la longueur du chemin optique d'un gyroscope à laser en anneau
JP2955703B2 (ja) 光路長制御用圧電アクチュエータ構造体
US5838440A (en) Path length controller piezo/wireboard bonding pattern
GB2037455A (en) Pathlength controller for a ring laser gyroscope

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): JP

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE FR GB IT LU NL SE