Coriolis effect transducer

• US 6,510,745 B2
• Filed: 12/28/2001
• Issued: 01/28/2003
• Est. Priority Date: 07/22/1999
• Status: Expired due to Term

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Geen, John Albert
• Primary Examiner(s): NOLAND, THOMAS
• Application Number:
  US10/032,640
• Publication Number:
  US 20020083757A1
• Time in Patent Office: 396 Days
• Field of Search: 738/613.54, 738/613.55, 738/613.56, 738/613.57, 73/12.7, 73/13.4, 735/040.2, 735/040.4, 73/13.8
• US Class Current: 73/861.356
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis
• CPC Class Codes: G01C 25/005 initial alignment, calibration or starting-up of inertial devices
• CPC Class Codes: G01F 1/8445 micromachined flowmeters
• CPC Class Codes: G01F 25/10 of flowmeters

Abstract

A method for testing a Coriolis transducer having a mass adapted vibrate along a vibratory direction in a resonant structure and undergo a displacement along a sensitive axis, perpendicular to the vibration, in response to an angular rate about a mutually perpendicular rate sensing axis. In the absence of an angular rate about the rate sensing axis, forces, F_{TEST VIBRATORY} and F_{TEST SENSITIVE}, are applied on the mass along the direction of vibration and along the sensitive axis, respectively, in a predetermined ratio, N. The output V_{OUT TEST} of the transducer is measured in response to the forces, F_{TEST VIBRATORY} and F_{TEST SENSITIVE}.

Claims

1. A Coriolis transducer, comprising:

a mass arranged to vibrate along a vibratory direction in a resonant structure and undergo a displacement along a sensitive axis, perpendicular to the vibration, in response to an angular rate about a rate sensing axis, such displacement being perpendicular to both the vibration and the rate sensing axis;

a vibratory direction force mechanism to apply a vibratory direction force, F_{TEST VIBRATORY}, on the mass along the vibratory direction; and

a sensitive axis force mechanism to apply simultaneously to the vibratory direction force, a force, F_{TEST SENSITIVE}, to the mass along the sensitive axis.

2. The transducer recited in claim 1 wherein the vibratory direction force mechanism and the sensitive axis force mechanism are in proximate regions of the transducer.

3. The transducer recited in claim 1 wherein the vibratory direction force mechanism and the sensitive axis force mechanism have matched physical and electrical characteristics.

4. A Coriolis transducer, comprising:

a resonant structure having a mass arranged to vibrate along a vibratory direction in a resonant structure and undergo a displacement along a sensitive axis, perpendicular to the vibration, in response to an angular rate about a rate sensing axis, such displacement being perpendicular to both the vibration and the rate sensing axis;

a vibratory direction force mechanism to apply a vibratory direction force, F_{TEST VIBRATORY}, on the mass along the vibratory direction during both a normal operating mode and during a test mode;

a sensitive axis force mechanism to apply simultaneously to the vibratory direction force, a force, F_{TEST SENSITIVE}, to the mass along the sensitive axis when such sensitive axis force mechanism is coupled to the mass; and

a switch to couple the sensitive axis force mechanism to the mass during a test mode and being adapted to de-couple the sensitive axis force mechanism from the mass during a normal operating mode.

5. The transducer recited in claim 4 wherein the vibratory direction force mechanism and the sensitive axis force mechanism are in proximate regions of the transducer.

6. The transducer recited in claim 4 wherein the vibratory direction force mechanism and the sensitive axis force mechanism have matched physical and electrical characteristics.