Oscillation gyro and an inspection apparatus therefor

• US 5,731,519 A
• Filed: 08/12/1996
• Issued: 03/24/1998
• Est. Priority Date: 08/24/1994
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation), Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Ogawa, Kenji
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): MOLLER, RICHARD ALAN
• Application Number:
  US08/695,435
• Time in Patent Office: 589 Days
• Field of Search: 73/504.02, 73/504.03, 73/504.12, 73/504.13, 73/504.14, 310/316, 310/317
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5649 Signal processing

Abstract

A vibration gyro which comprises an oscillator; a plurality of piezoelectric units for oscillating the oscillator in a predetermined driving-axis direction; piezoelectric unit driving means for driving the plurality of piezoelectric units by supplying an electric power to a common electrode of the plurality of piezoelectric units; a plurality of current-voltage converting means each for converting a current outputted from each of noncommon electrodes of the plurality of piezoelectric units to a voltage; eliminating means for eliminating damping components of the plurality of piezoelectric units by amplifying an output of the piezoelectric unit driving means by a predetermined amplification factor, shifting a phase of an amplified signal by a predetermined angle, shunting the amplified signal, and supplying each of shunted signals to each of the plurality of current-voltage converting means; adding means for adding outputs of the plurality of current-voltage converting means and for feeding back an added value respectively to the plurality of the current-voltage converting means; and error calculating means for calculating a difference between the outputs of the plurality of current-voltage converting means.

Claims

1. A vibration gyro comprising:

an oscillator;

a plurality of piezoelectric units for oscillating the oscillator in a predetermined driving-axis direction;

piezoelectric unit driving means for driving the plurality of piezoelectric units by supplying an electric power to a common electrode of the plurality of piezoelectric units;

a plurality of current-voltage converting means each for converting a current outputted from each of noncommon electrodes of the plurality of piezoelectric units to a voltage;

eliminating means for eliminating damping components of the plurality of piezoelectric units by amplifying an output of the piezoelectric unit driving means by a predetermined amplification factor, shifting a phase of an amplified signal by a predetermined angle, shunting the amplified signal, and supplying each of shunted signals to each of the plurality of current-voltage converting means;

a first shunt amount controlling means for controlling amounts of the shunted signals;

a second shunt amount controlling means connected to an output terminal of the piezoelectric unit driving means for shunting an output from the piezoelectric unit driving means, supplying shunted outputs respectively to the plurality of current-voltage converting means, and controlling shunt amounts; and

error calculating means for calculating a difference between outputs of the plurality of current-voltage converting means.

2. A vibration gyro comprising:

an oscillator;

a plurality of piezoelectric units for oscillating the oscillator in a predetermined driving-axis direction;

piezoelectric unit driving means for driving the plurality of piezoelectric units by supplying an electric power to a common electrode of the plurality of piezoelectric units;

a plurality of current-voltage converting means each for converting a current outputted from each of noncommon electrodes of the plurality of piezoelectric units to a voltage;

eliminating means for eliminating damping components of the plurality of piezoelectric units by amplifying an output of the piezoelectric unit driving means by a predetermined amplification factor, shifting a phase of an amplified signal by a predetermined angle, shunting the amplified signal, and supplying each of shunted signals to each of the plurality of current-voltage converting means;

error calculating means for calculating a difference between the outputs of the plurality of current-voltage converting means; and

wherein the eliminating means includes temperature detecting means for detecting an environmental temperature and an amplifying means wherein said predetermined amplification factor is changed by the temperature detecting means.

3. A vibration gyro comprising:

an oscillator;

a plurality of piezoelectric units for oscillating the oscillator in a predetermined driving-axis direction;

piezoelectric unit driving means for driving the plurality of piezoelectric units by supplying an electric power to a common electrode of the plurality of piezoelectric units;

a plurality of current-voltage converting means each for converting a current outputted from each of noncommon electrodes of the plurality of piezoelectric units to a voltage;

eliminating means for eliminating damping components of the plurality of piezoelectric units by amplifying an output of the piezoelectric unit driving means by a predetermined amplification factor, shifting a phase of an amplified signal by a predetermined angle, shunting the amplified signal, and supplying each of shunted signals to each of the plurality of current-voltage converting means;

error calculating means for calculating a difference between the outputs of the plurality of current-voltage converting means;

filter means provided at an output side of the error calculating means for restraining an output in a predetermined frequency domain; and

wherein the predetermined frequency domain is adjacent to a frequency approximately equal to a sum of or a difference between a first resonance frequency in a driving-axis direction of the oscillator and a second resonance frequency in a detecting-axis direction of the oscillator.

4. A vibration gyro comprising:

an oscillator;

a plurality of piezoelectric units for oscillating said oscillator in a predetermined driving-axis direction, each of the piezoelectric units having a common electrode in common with each of the other piezoelectric units, a noncommon electrode, and a resistive component;

piezoelectric unit driving means for driving said plurality of piezoelectric units by supplying an electric power signal to said common electrode of said plurality of piezoelectric units;

a plurality of current-voltage converting means each for converting a current output from the noncommon electrode of one of said plurality of piezoelectric units to a voltage and outputting said voltage as a converted signal;

eliminating means for eliminating damping components of the currents output from said plurality of piezoelectric units by amplifying by a predetermined amplification factor said electric power signal supplied from said piezoelectric unit driving means, altering by a predetermined angle a phase of the amplified electric power signal, dividing the amplified electric power signal having the altered phase, and supplying the divided signals to said plurality of current-voltage converting means;

error calculating means for calculating a difference between the outputs of said plurality of current-voltage converting means and outputting a signal representing said difference;

synchronism sampling means for outputting a synchronism signal in synchronism with a resistance error signal caused by an error due to said resistance components of said plurality of piezoelectric units based on the converted signals output from said plurality of current-voltage converting means, wherein the synchronism sampling means includes a phase advancing means for advancing a phase of an output of the piezoelectric unit driving means and is a comparing means for comparing an output of the phase advancing means with a reference value; and

synchronism detecting means connected to said error calculating means for detecting said signal output from said error calculating means based on said synchronism signal and outputting a detected signal, wherein said detected signal indicates an angular velocity of the oscillator.