Micromachined Z-axis vibratory rate gyroscope
First Claim
Patent Images
1. A sensor comprising:
- a substrate;
a mass connected to said substrate by a suspension system to vibrate in a plane parallel to a surface of said substrate;
a first plurality of electrode fingers projecting from said mass along a first axis in said plane;
a second plurality of electrode fingers connected to said substrate and projecting substantially along said first axis;
a third plurality of electrode fingers connected to said substrate but electrically isolated from said second plurality of electrode fingers, said third plurality of electrode fingers projecting substantially along said first axis, said second and third pluralities of electrode fingers interdigitated with said first plurality of electrode fingers such that each of said first plurality of electrode fingers is adjacent to one of said second plurality of electrode fingers and one of said third plurality of electrode fingers;
an electrostatic drive system to apply an oscillatory force to said mass along said first axis to cause said mass to vibrate;
a position sensor to measure a deflection of said mass in said plane; and
a first voltage source for applying a first DC voltage between said second and third pluralities of electrode fingers to cause said mass to vibrate, absent a Coriolis force, more precisely along said first axis.
1 Assignment
0 Petitions
Accused Products
Abstract
A microfabricated gyroscope to measure rotation about an axis perpendicular to the surface of the substrate. The driving electrodes, X-axis sensing electrodes, and Y-axis sensing electrodes may all be fabricated from a signal structural layer. The gyroscope includes movable sensing electrode fingers which are positioned between paired stationary sensing electrode fingers. The position of the proof mass along the Y-axis is measured by a capacitive bridge. A voltage differential may be applied between the pairs of stationary electrode fingers to reduce the quadrature error, and a bias voltage may be applied between the movable and stationary electrode fingers to adjust the Y-axis resonant frequency.
-
Citations
44 Claims
-
1. A sensor comprising:
-
a substrate; a mass connected to said substrate by a suspension system to vibrate in a plane parallel to a surface of said substrate; a first plurality of electrode fingers projecting from said mass along a first axis in said plane; a second plurality of electrode fingers connected to said substrate and projecting substantially along said first axis; a third plurality of electrode fingers connected to said substrate but electrically isolated from said second plurality of electrode fingers, said third plurality of electrode fingers projecting substantially along said first axis, said second and third pluralities of electrode fingers interdigitated with said first plurality of electrode fingers such that each of said first plurality of electrode fingers is adjacent to one of said second plurality of electrode fingers and one of said third plurality of electrode fingers; an electrostatic drive system to apply an oscillatory force to said mass along said first axis to cause said mass to vibrate; a position sensor to measure a deflection of said mass in said plane; and a first voltage source for applying a first DC voltage between said second and third pluralities of electrode fingers to cause said mass to vibrate, absent a Coriolis force, more precisely along said first axis. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A sensor comprising:
-
a substrate; a mass connected to said substrate by a suspension system to vibrate in a plane parallel to a surface of said substrate; a first plurality of electrode fingers projecting from said mass along a first axis in said plane; a second plurality of electrode fingers connected to said substrate and projecting substantially along said first axis; a third plurality of electrode fingers connected to said substrate but electrically isolated from said second plurality of electrode fingers, said third plurality of electrode fingers projecting substantially along said first axis, said second and third pluralities of electrode fingers interdigitated with said first plurality of electrode fingers such that each of said first plurality of electrode fingers is adjacent to one of said second plurality of electrode fingers and one of said third plurality of electrode fingers; an electrostatic drive system to apply an oscillatory force to said mass along said first axis to cause said mass to vibrate; and a voltage source for applying a DC voltage between said first plurality of electrode fingers and said second and third pluralities of electrode fingers to adjust the resonant frequency of vibrations of said mass along a second axis in said plane perpendicular to said first axis.
-
-
11. A microfabricated gyroscopic sensor for sensing rotation about a Z-axis, comprising:
-
a substrate; a mass connected to said substrate by a suspension system to vibrate in a plane parallel to a surface of said substrate; a drive system to apply an oscillatory force to said mass along a first axis in said plane to cause said mass to vibrate;
p1 a first plurality of electrode fingers projecting from said mass substantially along said first axis;a second plurality of electrode fingers connected to said substrate and projecting substantially along said first axis; a third plurality of electrode fingers connected to said substrate and projecting substantially along said first axis, said second and third pluralities of electrode fingers interdigitated with said first plurality of electrode fingers such that each of said first plurality of electrode fingers is adjacent to one of said second plurality of electrode fingers and one of said third plurality of electrode fingers; a position sensor coupled to said first plurality of electrode fingers for measuring a deflection of said mass along a second axis in said plane perpendicular to said first axis, wherein rotation of said mass about a Z-axis perpendicular to said surface and vibration of said mass along said first axis generates a Coriolis force to deflect said mass along said second axis; and a signal processor coupled to an output of said position sensor to generate a signal varying with a rate of rotation of said mass about the Z-axis. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
-
-
23. A microfabricated gyroscopic sensor, comprising:
-
a substrate; a mass connected to the substrate by a suspension system; a drive system to apply an oscillatory force to the mass along a drive axis substantially parallel to a surface of the substrate to cause the mass to vibrate; and a position sensor to measure a deflection of the mass along a sense axis substantially parallel to the surface of the substrate, wherein rotation of the mass about an axis of rotation substantially perpendicular to the surface of the substrate and vibration of the mass along the drive axis generates a Coriolis force to deflect the mass along the sense axis. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32)
-
-
33. A microfabricated gyroscopic sensor, comprising:
-
a substrate; a mass connected to the substrate by a suspension system; a drive system to apply an oscillatory force to the mass along a drive axis to cause the mass to vibrate; a position sensor to measure a deflection of the mass along a sense axis, wherein rotation of the mass about an axis of rotation and vibration of the mass along the drive axis generates a Coriolis force to deflect the mass along the sense axis; and a voltage source to apply a voltage between electrodes connected to the substrate to cause the mass to vibrate, absent the Coriolis force, more precisely along the drive axis. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41, 42)
-
-
43. A method of sensing rotation with a gyroscopic sensor including a mass connected to a substrate by a suspension system, comprising:
-
rotating the mass about an axis of rotation substantially perpendicular to a surface of the substrate; applying an oscillating force to the mass along a drive axis which is substantially parallel to the surface of the substrate to cause the mass to vibrate, rotation of the mass about the axis of rotation and vibration of the mass generating a Coriolis force to deflect the mass along a sense axis substantially parallel to the surface of the substrate and substantially perpendicular to the drive axis; and measuring a deflection of the mass along the sense axis.
-
-
44. A method of sensing rotation with a gyroscopic sensor including a mass connected to a substrate by a suspension system, comprising:
-
rotating the mass about an axis of rotation; applying an oscillatory force to the mass substantially along a drive axis to cause the mass to vibrate, rotation of the mass about the axis of rotation and vibration of the mass along the drive axis generating a Coriolis force to deflect the mass along a sense axis; measuring a deflection of the mass along the sense axis; and applying a voltage between electrode fingers connected to the substrate to cause the mass to vibrate, absent a Coriolis force, more precisely along the drive axis.
-
Specification