Force balanced piezoelectric rate sensor

• US 20040221651A1
• Filed: 05/07/2004
• Published: 11/11/2004
• Est. Priority Date: 05/08/2003
• Status: Abandoned Application

• Current Assignee: Triad Sensors Incorporated
• Original Assignee: Triad Sensors Incorporated
• Inventors: Schiller, Peter J.
• Application Number:
  US10/841,905
• Publication Number:
  US 20040221651A1
• Time in Patent Office: Days
• US Class Current: 73/514.34
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
• CPC Class Codes: G01P 15/0922 of the bending or flexing mode type
• CPC Class Codes: G01P 15/18 in two or more dimensions
• CPC Class Codes: G01P 2015/084 the mass being suspended at more than one of its sides, e.g. membrane-type suspension, so as to permit multi-axis movement of the mass

Abstract

The present invention provides a solid-state rotational rate sensor device formed by thin films for generating an electrical signal output proportional to the rate of rotation. The precision thin-film piezoelectric elements are configured and arranged on a semi-rigid structure to detect rotational rate while rejecting spurious noise created by package strain, thermal gradients, vibration, and electromagnetic interference.

Claims

1. A solid-state rotational rate sensor device, comprising:

a first actuator element that generates a first force proportional to a first electrical drive signal;

a second actuator element that generates a second force proportional to a second electrical drive signal; and

a mass coupled to the first and second actuator elements;

wherein motion of the mass along a first direction is in proportion to sum of the first force and the second force, and motion of the mass along a second direction is in proportion to difference between the first force and the second force.

2. The solid-state rotational rate sensor device of claim 1, further comprising:

a first sensor element that generates a first electrical motion signal proportional to motion of the mass along the first direction;

a second sensor element that generates a second electrical motion signal proportional to motion of the mass along the second direction.

3. The solid-state rotational rate sensor device of claim 2 wherein each of the actuator elements and each of the sensor elements are comprised of piezoelectric capacitors.

4. The solid-state rotational rate sensor device of claim 2 wherein each of the actuator elements and each of the sensor elements are comprised of a differential pair of piezoelectric capacitors.

5. The solid-state rotational rate sensor device of claim 4 wherein each of the differential pair of piezoelectric capacitors is comprised of:

a shared common lower conductive electrode;

a shared common plate of piezoelectric material;

an upper conductive electrode; and

means for connecting the differential pair of piezoelectric capacitors to electronic circuitry.

6. The solid-state rotational rate sensor device of claim 2, further comprising:

a first reference electrical signal;

a second reference electrical signal; and

an electrical control circuit that generates the first and second electrical drive signals;

wherein the electrical control circuit adjusts sum of the first and second electrical drive signals so as to make a first electrical motion signal equal to the first reference electrical signal and adjusts difference between the first and second electrical drive signals so as to make a second electrical motion signal equal to the second reference electrical signal.