US20020178816A1 - Counterbalanced silicon tuned multiple accelerometer-gyro - Google Patents
Counterbalanced silicon tuned multiple accelerometer-gyro Download PDFInfo
- Publication number
- US20020178816A1 US20020178816A1 US09/864,598 US86459801A US2002178816A1 US 20020178816 A1 US20020178816 A1 US 20020178816A1 US 86459801 A US86459801 A US 86459801A US 2002178816 A1 US2002178816 A1 US 2002178816A1
- Authority
- US
- United States
- Prior art keywords
- accelerometer
- gyro
- frame
- pendulum
- pendulums
- Prior art date
- Legal status (The legal status 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 status listed.)
- Granted
Links
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title description 2
- 229910052710 silicon Inorganic materials 0.000 title description 2
- 239000010703 silicon Substances 0.000 title description 2
- 238000009527 percussion Methods 0.000 claims abstract description 6
- 230000001133 acceleration Effects 0.000 claims description 15
- 238000000034 method Methods 0.000 description 4
- 239000000725 suspension Substances 0.000 description 4
- 238000013016 damping Methods 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 230000005484 gravity Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 1
- 238000005295 random walk Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
- G01P15/14—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of gyroscopes
-
- 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
- G01C19/56—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
- G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
- G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
- G01P15/097—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by vibratory elements
Abstract
Description
- 1. Field of the Invention
- The present invention relates to an inertial instrument and more specifically pertains to single axis and multi-axis vibrating accelerometers used as multi-sensors for measuring linear acceleration and rate of rotation of a moving body.
- 2. Description of Prior Art
- Gyroscopes are well known for use as angular velocity acceleration sensors for sensing angular velocity and acceleration which information is necessary for determining location, direction, position and velocity of a moving vehicle. There are gyroscopes of various types. Vibration type gyroscopes have attracted considerable attention from the standpoint of their low cost and high reliability.
- Vibrating structures have exhibited challenging problems, however. Attempts to overcome these problems have produced improved accelerometer gyroscopes. One example is shown in U.S. Pat. No. 4,679,434 granted Jul. 14, 1987 for an Integrated Force Balanced Accelerometer to the same inventor as the present application. The entire disclosure thereof is incorporated herein by reference. Another example which produces a micromachined accelerometer gyroscope by use of a substantially planar body can be found in U.S. Pat. No. 5,392,650 granted Feb. 28, 1995 for a Micromachined Accelerometer Gyroscope.
- In the present invention, gyro and accelerometer functions are combined in a single sensor unit which has a pair of counter oscillating accelerometers, each having a pendulum and vibrating element. The pendulum and vibrating element of each accelerometer are designed symmetrically so that the centers of mass for each are on a line which is parallel to the dither motion of the unit. The geometry of the two pendulums is configured so that the center of percussion of each is at the same point by providing interlaced pendulums with separate vibrating structures mounted on the same frame. The top and bottom covers have electrodes that work with areas defined by grooves or slots formed in the pendulum and vibrating elements to combine the pick-off and forcing functions with the pendulum tuning function. The frame of the sensor includes a pair of mounting tabs which are connected to the frame by respective compliant beams. Those compliant beams serve to lock together the dither frequency of the two vibrating driven elements and at the same time relieve stress imposed on the gyro due to differential thermal expansion between the gyro and its enclosure.
- The exact nature of this invention as well as its objects and advantages will become readily apparent from consideration of the following specification in relation to the accompanying drawings in which like reference numerals designate like parts throughout the figures thereof and wherein:
- FIG. 1 is a top plan view of the driven and sensing element of an accelerometer-gyro according to the present invention;
- FIG. 2 is a cross-section of a sensor in FIG. 3 showing a portion of a pendulum and the top and bottom covers;
- FIG. 3 is a top plan view of an alternate embodiment of the accelerometer-gyro according to the present invention; and
- FIG. 4 is a side plan view of an enclosure for the accelerometer-gyro of the present invention.
- An accelerometer or gyro disclosed in an application for Phase Insensitive Quadrature Error Nulling Method And Apparatus For Coriolis Angular Rate Sensors having U.S. patent application Ser. No. ______ filed on ______, naming the same inventors as named herein and assigned to the same assignee as the present application, illustrates a method and structure for nulling quadrature error. This method finds application in the present invention. The entire disclosure thereof is incorporated herein by reference as if fully set forth herein.
- The silicon tuned accelerometer and/or gyro of the present invention is based on the sensing and measuring of Coriolis induced accelerations acting on a vibrating accelerometer undergoing rotation as a means for measuring angular rotation rates.
- The gyro of the present invention measures angular rate by sensing the alternating Coriolis acceleration at the dither frequency which is in phase with the dither velocity and acts on the two pendulums of the counter-oscillating tuned accelerometers (sense elements). The difference in the coriolis acceleration sensed by the two pendulums is a measure of angular rate. The accelerometers measure linear acceleration by sensing the change in the magnitude of the sum of the quadrature signals between the two tuned accelerometers. In this design of the present invention, the normally unused quadrature signals are modulated by the acceleration acting along the input axis of the tuned accelerometers. This modulation occurs as a result of the pendulums of the tuned accelerometers deflecting open loop out of the plane in response to acceleration. As a result, the accelerometer's input axis senses components of the dither acceleration, resulting in quadrature signals. The difference of the quadrature signals remains a measure of the dither amplitude and can be used to maintain the dither amplitude and thereby provide a stable scale factor.
- By utilizing the phase insensitive quadrature nulling method as described in application Serial No. ______, a d.c. voltage is utilized to servo the quadrature error signal to null. The quadrature signal is utilized for the measurement of acceleration. The approach of the present invention in combining the gyro and accelerometer functions in a single sensor significantly simplifies the implementation of an inertial measurement unit (IMU) and consequently results in reduced costs and size. The cost reduction is the result of eliminating three accelerometers and their associated servo electronics.
- FIG. 7 is an illustrative sketch of the sensor portion of the accelerometer gyro of the present invention. This sensor portion is made up of a
frame 81 from which is suspended a firstvibratory device 85 by way of a plurality, and preferably fourdither suspensions pendulum mass 89 is suspended from the firstvibratory element 85 by way of asense flexure 87. - A second
vibratory element 95 is suspended fromframe 81 by four dither suspensions 91 a, 91 b, 91 c and 91 d. Asecond pendulum mass 101 is suspended from thevibratory element 95 by apendulum flexure 97. - This entire structure is formed out of a single wafer by etching out segments, S such as
segment vibratory structure 85.Segments vibratory structure 95.Major segment 115 is etched out around thefirst pendulum 89 and thesecond pendulum 101. - Accordingly, the first
vibratory structure 85 and the secondvibratory structure 95 move in the plane of the paper at their driven resonant frequency, whereas thefirst pendulum 89 and thesecond pendulum 101 oscillate about theirrespective flexure connections vibratory structures - As a result of design, the symmetry of the first
vibrating structure 85 and thefirst pendulum 89 and the secondvibrating structure 95 and itspendulum 101 have a symmetry which places the center of mass, or center of gravity, 105 of the first vibratory structure and pendulum and the center of mass, or center of gravity, 103 of the second vibratory structure and pendulum in a line which is parallel to the dither motion or vibration of the firstvibratory structure 85 and the secondvibratory structure 95. This produces counterbalanced operation. In addition, the geometry of thefirst pendulum 89 and thesecond pendulum 101 is configured to cause the respective centers of percussion of thefirst pendulum 89 and thesecond pendulum 101 to be coincident at the center ofpercussion 107. This is obtained by, among other things, adjusting the length of thependulums sense elements - The surfaces of the
vibratory structures pendulums metalized electrode patterns top cover 121 andbottom cover 125. - FIG. 2 is a cross-section of a portion of the structure of FIG. 1 showing a portion of
pendulum 101 interacting with top andbottom covers electrode patterns - Referring now to FIG. 3 which illustrates an alternative preferred embodiment of the accelerometer-gyro of the present invention, wherein the
frame 82 for the accelerometer-gyro has a pair ofmounting tabs devices tabs compliance beams frame 82 for example, by etching outslots tabs - The mounting
tabs frame 82 is thus mounted to theenclosure 153 through the twocompliant beams vibratory elements enclosure 153 and the accelerometer-gyro and itsframe 82. - The enclosure153 (FIG. 6) has a top 154 and a bottom 156 which are attached together in a well-known sealing relationship after the accelerometer-gyro is mounted therein. The enclosure maintains an atmosphere which is at a reduced pressure from atmospheric. The accelerometer-gyro in the reduced pressure atmosphere of
enclosure 153 experiences reduced damping of the drivenelements sensing elements pendulums
Claims (32)
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/864,598 US6474160B1 (en) | 2001-05-24 | 2001-05-24 | Counterbalanced silicon tuned multiple accelerometer-gyro |
EP02715097A EP1389299A1 (en) | 2001-05-24 | 2002-03-12 | Counterbalanced silicon tuned multiple accelerometer-gyro |
PCT/US2002/007408 WO2002095331A1 (en) | 2001-05-24 | 2002-03-12 | Counterbalanced silicon tuned multiple accelerometer-gyro |
TW091108304A TW528870B (en) | 2001-05-24 | 2002-04-23 | Counterbalanced silicon tuned multiple accelerometer-gyro |
US10/198,971 US6557415B2 (en) | 2001-05-24 | 2002-07-19 | Counterbalanced silicon tuned multiple accelerometer-gyro |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/864,598 US6474160B1 (en) | 2001-05-24 | 2001-05-24 | Counterbalanced silicon tuned multiple accelerometer-gyro |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/198,971 Division US6557415B2 (en) | 2001-05-24 | 2002-07-19 | Counterbalanced silicon tuned multiple accelerometer-gyro |
Publications (2)
Publication Number | Publication Date |
---|---|
US6474160B1 US6474160B1 (en) | 2002-11-05 |
US20020178816A1 true US20020178816A1 (en) | 2002-12-05 |
Family
ID=25343629
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/864,598 Expired - Lifetime US6474160B1 (en) | 2001-05-24 | 2001-05-24 | Counterbalanced silicon tuned multiple accelerometer-gyro |
US10/198,971 Expired - Lifetime US6557415B2 (en) | 2001-05-24 | 2002-07-19 | Counterbalanced silicon tuned multiple accelerometer-gyro |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/198,971 Expired - Lifetime US6557415B2 (en) | 2001-05-24 | 2002-07-19 | Counterbalanced silicon tuned multiple accelerometer-gyro |
Country Status (4)
Country | Link |
---|---|
US (2) | US6474160B1 (en) |
EP (1) | EP1389299A1 (en) |
TW (1) | TW528870B (en) |
WO (1) | WO2002095331A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1813951A1 (en) * | 2006-01-30 | 2007-08-01 | Infineon Technologies SensoNor AS | Inertial measurement unit and packages thereof |
Families Citing this family (16)
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FR2809174B1 (en) * | 2000-05-16 | 2002-07-12 | Commissariat Energie Atomique | VIBRATING STRUCTURE WITH TWO COUPLED OSCILLATORS, ESPECIALLY FOR A GYROMETER |
EP1253399B1 (en) * | 2001-04-27 | 2006-06-21 | STMicroelectronics S.r.l. | Integrated gyroscope of semiconductor material |
US6928872B2 (en) * | 2001-04-27 | 2005-08-16 | Stmicroelectronics S.R.L. | Integrated gyroscope of semiconductor material with at least one sensitive axis in the sensor plane |
US6651500B2 (en) * | 2001-10-03 | 2003-11-25 | Litton Systems, Inc. | Micromachined silicon tuned counterbalanced accelerometer-gyro with quadrature nulling |
US6859751B2 (en) * | 2001-12-17 | 2005-02-22 | Milli Sensor Systems & Actuators, Inc. | Planar inertial measurement units based on gyros and accelerometers with a common structure |
US7219548B2 (en) * | 2003-04-23 | 2007-05-22 | Northrop Grumman Corporation | Pickoff sensor obtaining of value of parameter from substantially zero net dampening torque location of pendulous sensor component |
US6868725B2 (en) * | 2003-04-23 | 2005-03-22 | Northrop Grumman Corporation | Hinge position location that causes pendulous axis to be substantially parallel with drive component direction |
US6904805B2 (en) * | 2003-06-03 | 2005-06-14 | Cherry Corporation | Accelerometer |
US7661312B2 (en) * | 2006-06-30 | 2010-02-16 | Honeywell International Inc. | Methods and systems for segregating sensors within a housing |
US7923623B1 (en) | 2007-10-17 | 2011-04-12 | David Beaty | Electric instrument music control device with multi-axis position sensors |
US9047850B1 (en) | 2007-10-17 | 2015-06-02 | David Wiley Beaty | Electric instrument music control device with magnetic displacement sensors |
US8338689B1 (en) | 2008-10-17 | 2012-12-25 | Telonics Pro Audio LLC | Electric instrument music control device with multi-axis position sensors |
US8272266B2 (en) * | 2009-04-09 | 2012-09-25 | Hewlett-Packard Development Company, L.P. | Gyroscopes using surface electrodes |
US9849376B2 (en) | 2012-05-02 | 2017-12-26 | Microsoft Technology Licensing, Llc | Wireless controller |
CN109580986A (en) * | 2018-11-23 | 2019-04-05 | 中国航空工业集团公司西安飞行自动控制研究所 | A kind of production method of monocrystalline silicon pendulum |
US11473909B2 (en) * | 2020-03-04 | 2022-10-18 | Invensense, Inc. | Use of MEMS gyroscope for compensation of accelerometer stress induced errors |
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-
2001
- 2001-05-24 US US09/864,598 patent/US6474160B1/en not_active Expired - Lifetime
-
2002
- 2002-03-12 EP EP02715097A patent/EP1389299A1/en not_active Withdrawn
- 2002-03-12 WO PCT/US2002/007408 patent/WO2002095331A1/en not_active Application Discontinuation
- 2002-04-23 TW TW091108304A patent/TW528870B/en not_active IP Right Cessation
- 2002-07-19 US US10/198,971 patent/US6557415B2/en not_active Expired - Lifetime
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1813951A1 (en) * | 2006-01-30 | 2007-08-01 | Infineon Technologies SensoNor AS | Inertial measurement unit and packages thereof |
Also Published As
Publication number | Publication date |
---|---|
US20030024313A1 (en) | 2003-02-06 |
EP1389299A1 (en) | 2004-02-18 |
US6557415B2 (en) | 2003-05-06 |
US6474160B1 (en) | 2002-11-05 |
WO2002095331A1 (en) | 2002-11-28 |
TW528870B (en) | 2003-04-21 |
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