Angular rate sensor with quadrature error compensation
First Claim
1. An angular rate sensor comprising:
- a substrate;
a drive mass flexibly coupled to said substrate, said drive mass comprising a frame structure having a central opening;
a sense mass suspended above said substrate and flexibly coupled to said drive mass via flexible support elements, said sense mass residing in said central opening; and
an electrode structure spaced apart from said substrate, said electrode structure comprising a sense plate fixedly attached to said drive mass at two locations on said frame structure so that said sense plate fully extends across at least a portion of said central opening and is vertically spaced apart from said sense mass, said electrode structure being configured to produce a sense signal that indicates movement of said sense mass relative to said electrode structure, whereinsaid drive mass, said sense mass, and said electrode structure move together with an oscillatory drive motion relative to a drive axis;
while said drive mass, said sense mass, and said electrode structure move together with said oscillatory drive motion, said flexible support elements enable said sense mass to oscillate relative to a sense axis that is perpendicular to said drive axis in response to an angular velocity about an input axis that is perpendicular to each of said drive and said sense axes, wherein oscillation of said sense mass in response to said angular velocity produces said sense signal between said sense mass and said electrode structure; and
said drive mass, said sense mass, and said electrode structure move together along said sense axis in response to quadrature error thereby resulting in substantially no relative motion between said sense mass and said electrode structure to reduce imposition of a signal error component from said quadrature error on said sense signal.
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Accused Products
Abstract
An angular rate sensor includes a substrate, a drive mass flexibly coupled to the substrate, and a sense mass suspended above the substrate and flexibly coupled to the drive mass via flexible support elements. An electrode structure is mechanically coupled to, but electrically isolated from, the drive mass and is spaced apart from the substrate so that it is not in contact with the substrate. The electrode structure is configured to produce a signal that indicates movement of the sense mass relative to the electrode when the sensor is subjected to angular velocity. When the angular rate sensor experiences quadrature error, the drive mass, the sense mass, and the electrode structure move together relative to the sense axis. Since the sense mass and the electrode structure move together in response to quadrature error, there is little relative motion between the sense mass and the electrode structure so that quadrature error is largely eliminated.
15 Citations
8 Claims
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1. An angular rate sensor comprising:
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a substrate; a drive mass flexibly coupled to said substrate, said drive mass comprising a frame structure having a central opening; a sense mass suspended above said substrate and flexibly coupled to said drive mass via flexible support elements, said sense mass residing in said central opening; and an electrode structure spaced apart from said substrate, said electrode structure comprising a sense plate fixedly attached to said drive mass at two locations on said frame structure so that said sense plate fully extends across at least a portion of said central opening and is vertically spaced apart from said sense mass, said electrode structure being configured to produce a sense signal that indicates movement of said sense mass relative to said electrode structure, wherein said drive mass, said sense mass, and said electrode structure move together with an oscillatory drive motion relative to a drive axis; while said drive mass, said sense mass, and said electrode structure move together with said oscillatory drive motion, said flexible support elements enable said sense mass to oscillate relative to a sense axis that is perpendicular to said drive axis in response to an angular velocity about an input axis that is perpendicular to each of said drive and said sense axes, wherein oscillation of said sense mass in response to said angular velocity produces said sense signal between said sense mass and said electrode structure; and said drive mass, said sense mass, and said electrode structure move together along said sense axis in response to quadrature error thereby resulting in substantially no relative motion between said sense mass and said electrode structure to reduce imposition of a signal error component from said quadrature error on said sense signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An angular rate sensor comprising:
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a substrate; a drive mass flexibly coupled to said substrate, said drive mass comprising a frame structure having a central opening; a sense mass suspended above said substrate and flexibly coupled to said drive mass via flexible support elements, said sense mass residing in said central opening; an electrode structure spaced apart from said substrate by an open gap, said electrode structure comprising a sense plate fixedly attached to said drive mass at two locations on said frame structure so that said sense plate fully extends across at least a portion of said central opening and is vertically spaced apart from said sense mass, said electrode structure being configured to produce a sense signal that indicates movement of said sense mass relative to said electrode structure; and
wherein said drive mass, said sense mass, and said electrode structure move together relative to the substrate.
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Specification