Vibratory rate gyroscope and methods of assembly and operation

• US 5,698,784 A
• Filed: 01/24/1996
• Issued: 12/16/1997
• Est. Priority Date: 01/24/1996
• Status: Expired due to Term

• Current Assignee: Gyration, Inc. (SMK Corporation)
• Original Assignee: Gyration, Inc. (SMK Corporation)
• Inventors: Land, Brian R., Hotelling, Steven P.
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): MOLLER, RICHARD ALAN
• Application Number:
  US08/593,534
• Time in Patent Office: 692 Days
• Field of Search: 73/504.16, 73/504.15, 73/504.12, 73/504.04, 73/504.02
• US Class Current: 73/504.16
• CPC Class Codes: G01C 19/5607 using vibrating tuning forks double-ended tuning forks using planar vibrating masses suspended at opposite ends G01C19/5719

Abstract

A vibrating gyroscope employs an electromagnetic transducer assembly which excites the vibration of the inertial element and senses its trajectory to provide an indication of movement relative to the plane of vibration of the inertial element. The transducer assembly allows for calibration of the gyroscope by positioning the transducer relative to the inertial element, thereby eliminating conventional requirements for selectively removing material from the inertial element during final calibration. Elastic members of the inertial element are manufactured in a monolithic structure to enhance the vibratory symmetry of the inertial element and the consistency and repeatability of its resonant properties. A phase-shifting circuit allows accurate extraction of rate information from the transducer while rejecting error signals. A mounting system facilitates mounting inertial elements to provide a simple implementations of multi-axis vibrating gyroscopes.

Claims

1. A vibratory gyroscope responsive to movement relative to a plane of vibration comprising:

a vibratory element including a pair of vibratory tynes disposed symmetrically about a common mounting for vibration within the plane;

a magnetic circuit including a source of magnetic flux and a magnetic return path mounted on each tyne to form a magnetic gap on each tyne of fixed spacing independent of vibration of the tyne; and

a coil assembly including electrical conductors disposed in the spacing of the magnetic gap of each tyne for conducting electrical signals indicative of vibratory movement of a tyne relative to the coil assembly associated therewith.

2. A vibratory gyroscope according to claim 1 wherein said coil assembly includes electrical conductors forming a coil disposed in the magnetic gap of one of the tynes for receiving electrical signals to drive vibratory movement of the tynes, and electrical conductors forming a coil disposed in the magnetic gap of the other of the tynes for supplying electrical signals indicative of detected vibratory movement of the tynes, and electrical conductors forming a coil disposed in the magnetic gap of at least said other of the tynes for supplying electrical signals indicative of vibratory movement of the tynes relative to a plane of vibratory movement of the magnetic circuits.

3. The vibratory gyroscope according to claim 2 wherein said coil assembly includes electrical conductors forming a coil disposed in the magnetic gaps of said one and other tynes for supplying electrical signals indicative of vibratory movement of the tynes relative to a plane of vibratory movement of the magnetic circuits.

4. A method of assembling a vibratory gyroscope including a pair of vibrating magnetic circuits each including a source of magnetic flux and an associated magnetic return path positioned to form a magnetic gap on each tyne of fixed spacing independent of vibration of the tyne, and including a coil assembly of electrical conductors disposed within the gap of each magnetic circuit, the method comprising the steps of:

orienting the magnetic circuits for vibration within a common plane;

positioning the coil assembly within the spacing of the gap of each magnetic circuit for intercepting magnetic flux in the gap;

vibrating the magnetic circuits in the common plane while detecting electrical signals on the conductors of the coil assembly;

processing the electrical signals from the coil assembly to provide indication of proper positional alignment of the coil assembly relative to the associated magnetic circuit, with minimum components in the electrical signals representative of physical errors in the assembly of the gyroscope; and

fixedly mounting the coil assembly in position within the magnetic gaps of the vibrating ,magnetic circuits to provide electrical signals indicative of movement relative to the common plane of the vibrating magnetic circuits with minimum electrical signal components representative of physical errors in the assembly of the gyroscope.

5. A method of operating a vibratory gyroscope including a pair of vibrating magnetic circuits each including a source of magnetic flux and an associated magnetic return path positioned to form a magnetic gap on each tyne of fixed spacing independent of vibrator movement, and including a coil assembly of a plurality of sets of electrical conductors disposed within the gap of each magnetic circuit, the method comprising the steps of:

applying electrical signal to a first set of electrical conductors of a coil assembly in a gap of at least one magnetic circuit to excite vibration thereof within a plane of the pair of magnetic circuits;

sensing electrical signal from a second set of electrical conductors of a coil assembly in a gap of another of the pair of magnetic circuits indicative of vibration thereof relative to vibration of said one of the magnetic circuits;

processing the electrical signal from the second set of electrical conductors for controlling electrical signal applied to the first set of electrical conductors;

sensing electrical signals from at least a third set of electrical conductors of the coil assembly in at least the gap in said another of the pair of magnetic circuits indicative of movement of the vibratory magnetic circuits relative to the plane of vibration thereof; and

processing the electrical signals from at least the third set of electrical conductors to provide electrical output indicative of movement of the vibratory gyroscope in a direction relative to a plane of the vibratory movement of the magnetic circuits.

6. An electromagnetic transducer assembly for a vibrating gyroscope comprising:

a pair of magnetic circuits, each mounted for vibratory movement within a common plane and each including a source of magnetic flux and a magnetic return path to form a gap on each tyne of fixed spacing independent of vibratory movement;

an assembly including a plurality of sets of electrical conductors positioned to form coils within the gap of each magnetic circuit, a first one of the coils in the spacing of one of the pair of gaps and a second one of the coils in the spacing of another of the pair of gaps each including a pair of substantially flat, spiral-wound segments that are in a plane normal to the spacing of the gap and are displaced along the direction of vibration of the vibrating magnetic circuits about a central region in which the spiral-wound conductors reverse spiraling orientation and are disposed substantially normal to said direction of vibration, a third one of the coils in the spacing of at least said another of the pair of gaps and including a substantially flat, spiral-wound segment in a plane normal to the spacing of the gap and displaced in the direction of vibration of the vibrating magnetic circuits about said central region and are aligned with said direction of vibration, the central regions of the first, second, and third, coils being aligned with the gaps of the associated magnetic circuits for electromagnetic interaction therewith relative to movement of the magnetic circuits with respect to the common plane of vibratory movement.