Wireless and passive acoustic wave rotation rate sensor

• US 20060238078A1
• Filed: 04/21/2005
• Published: 10/26/2006
• Est. Priority Date: 04/21/2005
• Status: Abandoned Application

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Liu, James ZT
• Application Number:
  US11/112,116
• Publication Number:
  US 20060238078A1
• Time in Patent Office: Days
• US Class Current: 310/338
• CPC Class Codes: G01C 19/5698 using acoustic waves, e.g. surface acoustic wave gyros

Abstract

A rotation rate sensing apparatus is configured from an acoustic wave device comprising a plurality of interdigital transducers for the SAW configuration or electrodes for vibration beams configuration. Such sensors are configured upon an elastic substrate. In the SAW configuration, the plurality of interdigital transducers includes a first interdigital transducer, a second interdigital transducer and a third interdigital transducer. A generator(s) can be formed from the first and third interdigital transducers, wherein the generator generates a standing wave subject to a Coriolis force by adding two progressive waves at each of the first and third interdigital transducers. In the vibration beams configuration, a drive beam(s) and pickup beam(s) can be implemented such that the vibration beams are excited through an RF signal and a Coriolis force excites the pickup beam(s) in order to obtain angular/rotation rate data.

Claims

1. A rotation rate sensing apparatus, comprising:

a surface acoustic wave device comprising a plurality of interdigital transducers configured upon an elastic substrate, wherein said plurality of interdigital transducers includes a first interdigital transducer, a second interdigital transducer and a third interdigital transducer;

an antenna connected to said plurality of interdigital transducers, wherein said antenna receives an excitation signal for the excitation of said rotation rate sensing apparatus and for transmitting angular rate data from said rotation rate sensing apparatus;

a generator formed from said first and third interdigital transducers, wherein said generator generates a standing wave subject to a Coriolis force by adding two progressive waves at each of said first and third interdigital transducers; and

a sensor formed from said second interdigital transducer, wherein said elastic substrate is rotatable in a first direction in order to excite an electric field at said sensor in order to detect an amplitude of said electric field, wherein said amplitude, which is proportional to the magnitude of said Coriolis force, provides an indication of angular rate data thereof.

2. The apparatus of claim 1 wherein said first, second and third interdigital transducers comprise at least one of the following:

a filter, a resonator, or a plurality of delay lines.

3. The apparatus of claim 1 wherein said second interdigital transducer is located centrally on said elastic substrate between said first and third interdigital transducers.

4. The apparatus of claim 1 wherein said first direction comprises a right direction relative to said elastic substrate.

5. The apparatus of claim 1 wherein said elastic substrate is formed from a piezoelectric material.

6. The apparatus of claim 1 wherein said plurality of interdigital transducers are arranged in a shape of a tuning fork, wherein said first interdigital transducer comprise a drive electrode and said third interdigital transducer comprises a pickup electrode and said second interdigital electrode comprises a tuning fork portion located centrally and perpendicular to said first interdigital transducer and said third interdigital transducer.

7. A rotation rate sensing apparatus, comprising:

a tuning fork device comprising a plurality of electrodes configured upon an elastic substrate, wherein said plurality of electrodes comprises a drive electrode and a pickup electrode, wherein said plurality of electrodes are connected to at least one antenna that receives an excitation signal for the excitation of said rotation rate sensing apparatus and for transmitting data from said rotation rate sensing apparatus, wherein flexural vibrations thereof occur in two perpendicular directions of beams thereof;

wherein said drive electrode is utilized to excite said beams into a vibration from an external RF interrogation signal provided by said excitation signal;

wherein a Coriolis force excites at least one other mode associated with said pickup electrode through which angular rate data associated with a rotating body located proximate to said rotation rate sensing apparatus;

wherein said at least one antenna comprises a first antenna connected to said pickup electrode, wherein said first antenna transmits data associated said angular rate data wirelessly to an interrogation unit; and

a second antenna for transmitting said angular rate data and receiving at least one interrogation signal wirelessly from said interrogation unit via a transmitter and receiver unit associated therewith.

8. The apparatus of claim 7 wherein said elastic substrate is formed from a piezoelectric material.

9. The apparatus of claim 7 wherein said elastic substrate comprises a thin piezoelectric film deposited on another elastic substrate associated therewith.

10. The apparatus of claim 7 wherein said flexural vibrations in two perpendicular directions of beams comprises an H-shaped tuning fork.

11. The apparatus of claim 7 wherein said flexural vibrations in two perpendicular directions of beams include thickness-shear vibrations in two perpendicular directions of plates thereof.

12. The apparatus of claim 7 wherein said flexural vibrations in two perpendicular directions of beams include radial and torsional vibrations of a circular cylindrical shell.

13. The apparatus of claim 7 wherein said flexural vibrations in two perpendicular directions of beams include degenerate modes of circular disks, shells, or rings adapted for use in forming a gyroscope comprising said.

14. A rotation rate sensing method, comprising:

providing a surface acoustic wave device comprising a plurality of interdigital transducers configured upon a elastic substrate, wherein said plurality of interdigital transducers includes a first interdigital transducer, a second interdigital transducer and a third interdigital transducer;

forming a generator from said first and third interdigital transducers, wherein said generator generates a standing wave subject to a Coriolis force by adding two progressive waves at each of said first and third interdigital transducers;

configuring a sensor from said second interdigital transducer, wherein said second interdigital transducer is located centrally on said elastic substrate between said first and third interdigital transducers and wherein said elastic substrate is rotatable in a first direction in order to excite an electric field at said sensor in order to detect an amplitude of said electric field, wherein said amplitude, which is proportional to the magnitude of said Coriolis force, provides an indication of angular rate data thereof; and

connecting said plurality of interdigital transducers to at least one antenna that receives an excitation signal for the excitation of said rotation rate sensing apparatus and for transmitting angular rate data from said rotation rate sensing apparatus, and;

providing at least one interrogation unit associated with a transmitter/receiver unit that receives said angular rate data from said at least one antenna and transmits at least one interrogation signal wirelessly from said interrogation electronics unit via said transmitter/receiver to said at least one antenna.

15. The method of claim 14 wherein said first, second and third interdigital transducers comprise at least one of the following:

a resonator, a filter or a plurality of delay lines.

16. The method of claim 14 wherein said second interdigital transducer is located centrally on said elastic substrate between said first and third interdigital transducers.

17. The method of claim 14 wherein said first direction comprises a right direction relative to said elastic substrate.

18. The method of claim 14 wherein said elastic substrate is formed from a piezoelectric material.

19. The method of claim 18 wherein said plurality of interdigital transducers are arranged in a shape of a tuning fork, wherein said first interdigital transducer comprise a drive electrode and said third interdigital transducer comprises a pickup electrode and said second interdigital electrode comprises a tuning fork portion located centrally and perpendicular to said first interdigital transducer and said third interdigital transducer.