Dual axis vibration rate gyroscope

• US 20070177316A1
• Filed: 03/11/2005
• Published: 08/02/2007
• Est. Priority Date: 03/12/2004
• Status: Active Grant

• Current Assignee: InterDigital CE Patent Holdings SAS (InterDigital, Inc.)
• Original Assignee: Thomson Licensing (Vantiva SA)
• Inventors: Bayer, Lex, Hotelling, Steven, Land, Brian
• Granted Patent: US 7,673,510 B2
• Time in Patent Office: Days
• US Class Current: 361/51
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
• CPC Class Codes: G01C 19/5705 using masses driven in reciprocating rotary motion about an axis
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis
• CPC Class Codes: G01C 25/00 Manufacturing, calibrating, cleaning, or repairing instruments or devices referred to in the other groups of this subclass testing, calibrating or compensating compasses G01C17/38

Abstract

A dual-axis rotational rate sensor having two vibratory masses coupled to a restoring element and driven in a resonant counter-phase motion, wherein the two masses vibrate with equal but opposite amplitudes along a single axis. The vibratory structure also accommodates motion of the masses in a plane orthogonal to the vibratory axis. Measurement of the motion of the masses in two axes in this plane provides signals directly responsive to rotation of the sensor about two orthogonal axes. Measurement and drive is facilitated by the use of magnetic masses and electromagnetic drive and sense transducers.

Claims

1. A vibratory rotational rate sensor comprising:

a vibratory element including a pair of vibratory masses disposed symmetrically along a common axis for vibration along the axis;

a driver coupled to at least one vibratory mass for inducing periodic motion in the vibratory masses along the axis;

a first sense circuit coupled to at least one of the vibratory masses for sensing motion of the vibratory mass in one direction orthogonal to the vibratory axis; and

a second sense circuit coupled to at least one of the vibratory masses for sensing motion of the vibratory mass in another direction orthogonal to the vibratory axis.

2. A vibratory rotational rate sensor as in claim 1 wherein the driver induces counter-phase motion between the vibratory masses.

3. A vibratory rotational rate sensor as in claim 1 wherein the vibratory masses include magnetic elements and the driver and the sense circuits include electromagnetic elements.

4. A vibratory rotational rate sensor as in claim 1 wherein the driver is coupled to one vibratory mass and the sense circuits are coupled to the other vibratory mass.

5. A vibratory rotational rate sensor as in claim 1 wherein the driver is periodically coupled to one vibratory mass and the sense circuits are coupled to the same vibratory mass during times when the driver is not.

6. A vibratory rotational rate sensor as in claim 1 wherein the one and the other directions are coplanar and generally orthogonal to one another.

7. A vibratory rotational rate sensor as in claim 1 including a motion sensor for sensing the amplitude and phase of the motion of the vibratory masses along the vibratory axis, wherein the motion sensor is coupled to the driver, and the driver drives the vibratory masses in a repeatable manner in response to the sensed amplitude and phase.

8. A vibratory rotational rate sensor as in claim 1 further comprising a planar restoring element having resilient first members coupled to one of the masses and resilient second members coupled to the other of the masses.

9. A vibratory rotational rate sensor as in claim 8 further comprising a single homogeneous restoring element having resilient first members coupled to each of the masses.

10. A vibratory rotational rate sensor as in claim 8 wherein the resilient first and second members are elongated such that they have a length greater than the straight-line distance between their ends.

11. A vibratory rotational rate sensor as in claim 8 wherein the restoring element further includes resilient mounting members for connecting the vibratory assembly to an external mount.

12. A vibratory rotational rate sensor as in claim 1 wherein the resonances of the counter-phase motion and the sensed motion are sufficiently close to magnify the sense mode motion and other resonant modes are spaced sufficiently far in frequency so that they can be effectively removed by filtering.

13. A vibratory rotational rate sensor as in claim 8 wherein the planar restoring element is radially X-fold symmetric, X being an integer 3 or greater.

14. A method for operating a vibratory rotational rate sensor, the rate sensor including a pair of vibratory masses disposed symmetrically along a common axis for vibration along the axis, the method comprising the steps of:

driving at least one vibratory mass for inducing periodic motion in the vibratory masses along the axis;

sensing motion of at least one of the vibratory masses in one direction orthogonal to the vibratory axis; and

sensing motion of at least one of the vibratory masses in another direction orthogonal to the vibratory axis.

15. A method for operating a vibratory rotational rate sensor as in claim 14 wherein the step of driving induces counter-phase motion between the vibratory masses.

16. A method for operating a vibratory rotational rate sensor as in claim 14 wherein the vibratory masses include magnetic elements and the steps of sensing are done electromagnetically.

17. A method for operating a vibratory rotational rate sensor as in claim 14 wherein the driver is coupled to one vibratory mass and the sense circuits are coupled to the other vibratory mass, wherein the step of driving drives one of the vibratory masses and the steps of sensing sense the motion of the other vibratory mass.

18. A method for operating a vibratory rotational rate sensor as in claim 14 wherein the step of driving drives one vibratory mass intermittently and the steps of sensing sense the motion of the one vibratory mass during times when it is not being driven.

19. A method for operating a vibratory rotational rate sensor as in claim 14 wherein the one and the other directions are coplanar and generally orthogonal to one another.

20. A method for operating a vibratory rotational rate sensor as in claim 14 further including the step of sensing the amplitude and phase of the motion of at least one of vibratory masses along the vibratory axis, and the step of driving drives the vibratory masses in a repeatable manner in response to the sensed amplitude and phase.