Rotational vibration gyroscope

• US 5,511,419 A
• Filed: 08/01/1994
• Issued: 04/30/1996
• Est. Priority Date: 12/19/1991
• Status: Expired due to Term

• Current Assignee: Apple Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Dunn, William C.
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): MOLLER, RICHARD ALAN
• Application Number:
  US08/283,342
• Time in Patent Office: 638 Days
• Field of Search: 73/505, 73/510, 73/517 AV, 73/504.08, 73/504.09, 73/504.11, 73/504.12
• US Class Current: 73/504.08
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis
• CPC Class Codes: G01P 15/18 in two or more dimensions

Abstract

A rotor affixed to a central mounting post by helical springs for oscillatory rotary movement about the post. The post defining a Z axis and the sensing capacitors adjacent the rotor defining X and Y axes. The rotor, helical springs and post being formed of polysilicon in a single emiconductor process step.

Claims

1. A method of operating a rotational vibration gyroscope including a mounting post fixedly attached to a base and defining a first axis, a rotor positioned in a plane perpendicular to the post, springs affixed at one end to the post and at another end to the rotor, and mounting the rotor for oscillatory rotary movement about the post, oscillatory motion driving apparatus mounted adjacent to the rotor, and sensing apparatus, positioned adjacent to the rotor and defining second and third axes mutually perpendicular to each other and to the first axis, comprising the steps of:

supplying signals to the driving apparatus to produce oscillatory motion in the rotor about the first axis;

utilizing the sensing apparatus to sense movement of the rotor about the third axis, produced by Coriolis forces reacting to movement of the gyroscope about the second axis and to sense movement of the rotor about the second axis, produced by Coriolis forces reacting to movement of the rotor about the third axis; and

supplying signals to the sensing apparatus to maintain the rotor approximately centered while simultaneously measuring the Coriolis forces on the rotor.

2. A method of operating a rotational vibration gyroscope as set forth in claim 1 wherein the step of supplying signals to the driving apparatus is further characterized by sensing the oscillatory movement and driving the rotor to a predetermined distance in each of two oscillatory directions.

3. A method of operating a rotational vibration gyroscope as set forth in claim 2 wherein the predetermined distance is chosen to produce an oscillatory movement approximately equal to a natural resonant frequency of the rotational vibration gyroscope.