Micromachined rate and acceleration sensor

• US 5,920,011 A
• Filed: 01/20/1997
• Issued: 07/06/1999
• Est. Priority Date: 02/08/1991
• Status: Expired due to Term

• Current Assignee: L-3 Communications Corporation (L3Harris Technologies, Inc.)
• Original Assignee: Alliedsignal Inc. (Honeywell International Inc.)
• Inventors: Hulsing, Rand H. II
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US08/786,185
• Time in Patent Office: 897 Days
• Field of Search: 73/504.04, 73/504.12, 73/504.14, 73/504.15, 73/504.16, 73/510
• US Class Current: 73/504.04
• CPC Class Codes: F02G 1/044 having at least two working members, e.g. pistons, delivering power output
• CPC Class Codes: F02G 1/0445 Engine plants with combined cycles, e.g. Vuilleumier
• CPC Class Codes: F02G 2250/18 Vuilleumier cycles
• CPC Class Codes: F02G 2253/03 Stem seals
• CPC Class Codes: F16F 2230/0052 Physically guiding or influencing
• CPC Class Codes: F16F 2230/34 Flexural hinges
• CPC Class Codes: F16L 37/24 in which the connection is made by inserting one member axially into the other and rotating it to a limited extent, e.g. with bayonet action
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis
• CPC Class Codes: G01C 19/5747 each sensing mass being connected to a driving mass, e.g. driving frames
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/097 by vibratory elements
• CPC Class Codes: G01P 15/18 in two or more dimensions
• CPC Class Codes: G01P 2015/0828 the mass being of the paddle type being suspended at one of its longitudinal ends
• CPC Class Codes: Y10S 73/01 Vibration

Abstract

A sensor (10) is disclosed for measuring the specific force and angular rotation rate of a moving body and is micromachined from a silicon substrate (16). First and second accelerometers (32a and b) are micromachined from the silicon substrate (16), each having a force sensing axis (38) and producing an output signal of the acceleration of the moving body along its force sensing axis (38). The first and second accelerometers (32a and b) are mounted within the substrate (16) to be moved along a vibration axis (41). The first and second accelerometers (32a and b) are vibrated or dithered to increase the Coriolis component of the output signals from the first and second accelerometers (32a and b). A sinusoidal drive signal of a predetermined frequency is applied to a conductive path (92) disposed on each of the accelerometers. Further, magnetic flux is directed to cross each of the conductive paths (92), whereby the interaction of the magnetic flux and of the drive signal passing therethrough causes the desired dithering motion. A link (72) is formed within the silicon substrate (16) and connected to each of the accelerometers (32a and b), whereby motion imparted to one results in a like, but opposite motion applied to the other accelerometer (32). Further, a unitary magnet (20) and its associated flux path assembly direct and focus the magnetic flux through the first and second accelerometers (32a and b) formed within the silicon substrate (16).

Claims

1. In an apparatus for measuring the specific force and angular rotation rate of a moving body, a micromachined structure comprising:

a) a monolithic substrate having first and second substantially planar surfaces disposed substantially parallel to each other;

b) a first accelerometer formed of said substrate for producing a first output signal indicative of the acceleration applied to the moving body;

c) a second accelerometer formed of said substrate for producing a second output signal indicative of the acceleration applied to the moving body;

d) mounting means formed of said substrate for mounting said first and second accelerometers to move said first and second accelerometers along a vibration axis substantially parallel to said first and second planar surfaces;

e) a link connected between said first and second accelerometers, said link imparting a substantially equal and opposite motion to said one of said first and second accelerometers when the other of said first and second accelerometers is moved; and

f) means for dithering each of said first and second accelerometers along said vibration axis to enable measurement of said specific force and angular rotation rate of said moving body.

2. The measuring apparatus as claimed in claim 1, wherein said first accelerometer further comprises a first force sensing axis for producing said first output signal which is indicative of the acceleration of the moving body along said first force sensing axis.

3. The measuring apparatus as claimed in claim 2, wherein said second accelerometer further comprises a second force sensing axis for producing said first output signal which is indicative of the acceleration of the moving body along said second force sensing axis.

4. The measuring apparatus as claimed in claim 3, wherein said first force sensing axis extends in a direction substantially opposite to the direction of said second force sensing axis.