Bias and quadrature reduction in class II coriolis vibratory gyros
AssigneeNorthrop Grumman Guidance and Electronics Company, Inc.
InventorsRobert E. Stewart, Stanley F. Wyse
Life of this patent
Estimating the term…
Abstract
The method and apparartus in one embodiment may have the steps of: providing a two-dimensional axisymmetric oscillator having a beam containing two principal elastic axes and two principal damping axes; driving the beam with drive components to oscillate; driving, during a first period, the beam along a drive axis of the beam in a direction normal to one pair of faces of the beam while Coriolis coupled vibration is sensed along a sense axis of the beam normal to an orthogonal pair of faces of the beam; reversing, during a second period, drive and sense axes driving the beam; reducing a bias of the beam to zero; and reducing a quadrature of the beam to zero.
Claims26
An apparatus, comprising:
- a class II coriolis vibratory gyro (CVG) having a beam;
- drive components operatively coupled to the beam, the drive components driving the beam to oscillate with a Coriolis induced vibration in two orthogonal faces of the beam;
- a bias that is equal to sin 2θτ(1/τ1−1/τ2)/2k rad/sec;
- a quadrature that is equal to sin 2θω(ω1−ω2)/2k rad/sec;
- where:
- θτ=angle between vibration drive axis and principal damping axis;
- θω=angle between vibration drive axis and principal elastic axis;
- τ1 and τ2=damping time constant in each of the principal damping axes;
- ω1 and ω2=resonant frequency in each of the principal elastic axes;
- and
- k=geometry dependant scaling constant;
- and
- means for reducing the bias to substantially zero;
- and
- means for reducing the quadrature to substantially zero.
A method, comprising:
- providing a class II coriolis vibratory gyro (CVG) having a beam, a bias of the gyro being equal to sin 2θτ(1/τ1−1/τ2)/2k rad/sec, and a quadrature of the gyro being equal to sin 2θω(ω1−ω2)/2k rad/sec;
- where:
- θτ=angle between vibration drive axis and principal damping axis;
- θω=angle between vibration drive axis and principal elastic axis;
- τ1 and τ2=damping time constant in each of the principal damping axes;
- ω1 and ω2=resonant frequency in each of the principal elastic axes;
- and
- k =geometry dependant scaling constant;
- and
- reducing a bias to zero;
- and
- reducing a quadrature to zero;
- and
- driving the beam to oscillate with a Coriolis induced vibration in two orthogonal faces of the beam.
An apparatus, comprising:
- a beam in a vibrating beam gyro;
- drive components operatively coupled to the beam, the drive components driving the beam to oscillate;
- a Coriolis induced vibration in two orthogonal faces of the beam;
- means for reducing a bias of the beam to zero;
- and
- means for reducing a quadrature of the beam to zero.
A method, comprising:
- providing a two-dimensional axisymmetric oscillator having a beam containing two principal elastic axes and two principal damping axes;
- driving the beam with drive components to oscillate;
- reducing a bias of the beam to zero;
- and
- reducing a quadrature of the beam to zero.
A method, comprising:
- providing a two-dimensional axisymmetric oscillator having a beam containing two principal elastic axes and two principal damping axes;
- driving the beam with drive components to oscillate across corners of the beam at approximately 45 degrees to sides of the beam;
- driving, during a first period, the beam along a drive axis of the beam in a direction normal to one pair of faces of the beam while Coriolis coupled vibration is sensed along a sense axis of the beam normal to an orthogonal pair of faces of the beam;
- reversing, during a second period, drive and sense axes driving the beam;
- reducing a bias of the beam to zero;
- and
- reducing a quadrature of the beam to zero.
Dependencies are inferred from the claim text.