Oscillation gyroscope

• US 5,677,486 A
• Filed: 11/13/1995
• Issued: 10/14/1997
• Est. Priority Date: 11/14/1994
• Status: Expired due to Term

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Fujimoto, Katsumi, Nakamura, Takeshi, Ebara, Kazuhiro
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): MOLLER, RICHARD ALAN
• Application Number:
  US08/556,714
• Time in Patent Office: 701 Days
• Field of Search: 73/504.12, 73/540.14, 73/504.02, 310/316
• US Class Current: 73/504.14
• CPC Class Codes: G01C 19/5649 Signal processing

Abstract

An oscillation gyroscope 10 includes an oscillator 11 comprising an equilateral triangular prism-shaped vibrating body 12 and piezoelectric elements 14a to 14c. An oscillator circuit 26 including an inverse amplification circuit 28 and a phase circuit 30 is connected between the piezoelectric elements 14a, 14b and the piezoelectric element 14c via resistors 22 and 24. The piezoelectric elements 14a and 14b are connected to a differential amplification circuit 32 and the output signal of a addition signal computing unit 34 is added to the output signal of the differential amplification circuit 32 by an adder 33. A signal of the same phase or an inverse phase with respect to the output signal of the phase circuit 30 or an inverse amplification circuit 28 is level-adjusted and outputted from the addition signal computing unit 34. A composite signal made up of the output signal of the differential amplification circuit 32 and the output signal of the addition signal computing unit 34 is detected by a synchronous detector 36 and smoothed by a smoothing circuit 38.

Claims

1. An oscillation gyroscope comprising:

a drivable vibrating body;

a plurality of drive/detection devices associated with said vibrating body and operable for both driving said vibrating body and detecting signals corresponding to a rotation angular velocity of said vibrating body;

an oscillator circuit, connected to said drive/detection devices, for driving said vibrating body;

a differential circuit connected to said drive/detection devices for receiving said signals from each of said drive/detection devices and outputting a differential output signal corresponding to the rotation angular velocity;

an addition signal computing unit for computing at least one signal having a phase difference with respect to said differential signal; and

an adder for adding the respective outputs of said differential circuit and said addition signal computing circuit;

wherein said phase difference and an amplitude of said at least one signal from said additional signal computing unit are such that an adder output signal from said adder obtained by adding said at least one signal and said differential output signal under the condition that no rotation angular velocity is applied to said vibrating body has an amplitude less than that of said differential output signal.

2. The oscillation gyroscope according to claim 1, wherein said phase difference is 90°

, said oscillator circuit includes an inverse amplification circuit and a phase circuit for adjusting a phase of an output signal of said inverse amplification circuit, and an output signal of said phase circuit is inputted to said addition signal computing unit.

3. The oscillation gyroscope according to claim 1, wherein said phase difference is 90°

said oscillator circuit includes an inverse amplification circuit and a phase circuit for adjusting a phase of an output signal of said inverse amplification circuit, and said oscillator circuit further includes a phase correction circuit for modifying the phase of the output signal of said inverse amplification circuit, and an output signal of said phase correction circuit is inputted to said addition signal computing unit.

4. The oscillation gyroscope according to claim 1, wherein said phase difference is 90°

, further comprising a summation circuit for synthesizing an output signal of the plurality of said drive/detection devices and a phase correction circuit for modifying a phase of an output signal of said summation circuit, and wherein an output signal of said phase correction circuit is inputted to said addition signal computing unit.

5. The oscillation gyroscope according to claim 1, wherein said phase difference is 0°

, said oscillator circuit includes an inverse amplification circuit and a phase circuit for adjusting a phase of an output signal of said inverse amplification circuit, and an output signal of said phase circuit is inputted to said addition signal computing unit.

6. The oscillation gyroscope according to claim 1, wherein said phase difference is 0°

, further including a phase correction circuit for modifying the phase of the output signal of said inverse amplification circuit, and wherein an output signal of said phase correction circuit is inputted to said addition signal computing unit.

7. The oscillation gyroscope according to claim 1, wherein said phase difference is 0°

, further comprising a summation circuit for synthesizing an output signal of the plurality of said drive/detection devices and a phase correction circuit for modifying a phase of an output signal of said summation circuit, and wherein an output signal of said phase correction circuit is inputted to said addition signal computing unit.

8. The oscillation gyroscope according to claim 1, wherein said phase difference is 180°

, said oscillator circuit includes an inverse amplification circuit and a phase circuit for adjusting a phase of an output signal of said inverse amplification circuit, and an output signal of said phase circuit is inputted to said addition signal computing unit.

9. The oscillation gyroscope according to claim 1, wherein said phase difference is 180°

, further including a phase correction circuit for modifying the phase of the output signal of said inverse amplification circuit, and wherein an output signal of said phase correction circuit is inputted to said addition signal computing unit.

10. The oscillation gyroscope according to claim 1, wherein said phase difference is 180°

, further comprising a summation circuit for synthesizing an output signal of the plurality of said drive/detection devices and a phase correction circuit for modifying a phase of an output signal of said summation circuit, and wherein an output signal of said phase correction circuit is inputted to said addition signal computing unit.

11. The oscillation gyroscope according to claim 1, further comprising a synchronous detector wherein a signal made up of said differential output signal of said differential circuit and an output signal of said addition signal computing unit is detected by being synchronized with signals corresponding to rotation angular velocities in the synchronous detector, and the output of the synchronous detector is supplied to the addition signal computing unit so as to control the level of an output signal of the addition signal computing unit.

12. The oscillation gyroscope according to claim 1, wherein said phase difference and said amplitude of said at least one signal are such that said adder output signal has its maximum level when said at least one signal has a zero level.