ANGULAR RATE SENSOR

• US 3,842,681 A
• Filed: 07/19/1973
• Issued: 10/22/1974
• Est. Priority Date: 07/19/1973
• Status: Expired due to Term

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Clarence D. Mumme
• Inventors: Mumme, Clarence D.
• Primary Examiner(s): Gill, James J.
• Application Number:
  US05/380,629
• Time in Patent Office: 460 Days
• Field of Search: 73/505
• US Class Current: 73/504.15
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces

Abstract

A multiple axis angular rate inertial sensor measures the flexing of vibrating piezoelectric cantilevers induced by Coriolis forces, when the instrument is turned about an axis, in a mechanically resonant system excited by similar piezoelectric cantilever elements.

Claims

1. An instrument for measuring angular rate of rotation of an object about at least a first axis comprising:

torsion rod means rigidly secured at each end thereof to said object and extending along a second axis normal to said first axis for torsional oscillation thereabout, first and second oppositely extending balanced vibratory cantilever means rigidly secured to said torsion rod means between said ends, said first vibratory cantilever means including electrically responsive vibration driver means for applying torsional oscillations to said torsion rod means, said second vibratory cantilever means including vibration pick-off means for providing an alternating electrical output signal of frequency proportional to the frequency of said torsional oscillations, and opposed cooperative radially extending vibratory electrically responding sensor means rigidly secured to said torsion rod means between said ends, angularly spaced from said first and second oppositely extending balanced vibratory cantilever means in a common plane and responsive to angular rate of rotation about said first axis for generating an output electrical signal representative in polarity and amplitude of said angular rate of rotation about said first axis.

2. Apparatus as described in claim 1 additionally including amplifier means responsive to said second oppositely extending balanced vibratory cantilever means vibration pick-off means for driving said first oppositely extending balanced vibratory cantilever means vibration driver means.

3. Apparatus as described in claim 2 further including:

second opposed cooperative radially extending vibratory electrically responding sensor means rigidly secured to said torsion rod means between said ends and responsive to angular rate of rotatIon about a second axis distinct from said first axis for generating an output signal representative in polarity and amplitude of said angular rate of rotation about said second axis.

4. Apparatus as described in claim 3 further including:

first demodulator means responsive to said opposed cooperative radially extending vibratory electrically responding sensor means and to said amplifier means, second demodulator means responsive to said second opposed cooperative radially extending vibratory electrically responding sensor means, and utilization means responsive to said first and second demodulator means.

5. Apparatus as described in claim 2 wherein said first oppositely extending balanced vibratory cantilever means comprises thin elongate electric-field-responsive piezoelectric cantilever means having a free end vibratable about said torsion rod means.

6. Apparatus as described in claim 5 wherein said second oppositely extending balanced vibratory cantilever means comprises thin elongate electric-field-generating piezoelectric cantilever means having a free end vibratable about said torsion rod means.

7. Apparatus as described in claim 6 wherein said opposed cooperative radially extending vibratory electrically responding sensor means comprise thin elongate electric-field-generating piezoelectric cantilever means having free ends vibratable parallel to said torsion rod means.

8. Apparatus as described in claim 1 wherein at least said first and second oppositely extending vibratory cantilever means and said opposed cooperative radially extending vibratory electrically responding means are each balanced with respect to said torsion rod for the purpose of rendering negligible the effects of linear acceleration of the instrument.