Oscillation gyro and an inspection apparatus therefor

• US 5,932,802 A
• Filed: 10/17/1997
• Issued: 08/03/1999
• 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
• Assistant Examiner(s): MOLLER, RICHARD ALAN
• Application Number:
  US08/953,628
• Time in Patent Office: 655 Days
• Field of Search: 73/1.77, 73/1.78, 73/1.75, 73/1.38, 73/1.82, 73/504.02, 73/504.03, 73/504.04, 73/504.12
• US Class Current: 73/504.02
• 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. An inspection apparatus for a vibration gyro comprising:

holding means for attachably and detachably holding an oscillating unit comprising an oscillator and a plurality of piezoelectric units provided to the oscillator for oscillating the oscillator in a predetermined driving-axis direction and connecting the oscillating unit to a surrounding circuit;

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

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

adding means for calculating outputs of the plurality of current-voltage converting means and feeding back an added value of the outputs respectively 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;

added output inspecting means for calculating a first transfer function of the adding means based on an output of the piezoelectric unit driving means and the added value of the adding means;

error calculation output inspecting means for calculating a second transfer function of the error calculating means based on the output of the piezoelectric unit driving means and an output of the error calculating means; and

wherein a first difference between resistance components of the plurality of piezoelectric units or a second difference between reactance components of the plurality of piezoelectric units is determined based on a gain and a phase difference of the error calculation output inspecting means at a resonance frequency in a driving-axis direction of the oscillating unit provided by the added output inspecting means.

2. The inspection apparatus according to claim 1, further comprising a temperature controlling means for changing an environmental temperature of the oscillating unit.

3. An inspection apparatus for a vibration gyro comprising:

a holding member attachably and detachably holding an oscillating unit comprising an oscillator and a plurality of piezoelectric units provided to the oscillator for oscillating the oscillator in a predetermined driving-axis direction and connecting the oscillating unit to a surrounding circuit;

a piezoelectric unit driver supplying electric power to a common electrode of the plurality of piezoelectric units thereby driving the plurality of piezoelectric units;

a plurality of current-voltage converters each converting a current output from a noncommon electrode of one of the plurality of piezoelectric units to a voltage;

an adder connected to outputs of the plurality of current-voltage converters, calculating and feeding back an added value of the current-voltage converter outputs respectively to each of the plurality of current-voltage converters;

an error calculator connected to the outputs of the plurality of current-voltage converters and calculating a difference between the outputs of the plurality of current-voltage converters;

an added output inspecting circuit calculating a first transfer function of the adder based on an output of the piezoelectric unit driver and the added value of the adder; and

an error calculation output inspecting circuit calculating a second transfer function of the error calculator based on the output of the piezoelectric unit driver and an output of the error calculator;

wherein a first difference between resistance components of the plurality of piezoelectric units or a second difference between reactance components of the plurality of piezoelectric units is determined based on a gain and a phase difference of the error calculation output inspecting circuit at a resonance frequency in a driving-axis direction of the oscillating unit provided by the added output inspecting circuit.

4. The inspection apparatus according to claim 3, further comprising a temperature controller changing an environmental temperature of the oscillating unit.