Axis aligned rate and acceleration sensor
First Claim
Patent Images
1. An angular rate sensor comprising:
- a support structure;
a generally planar substrate, having an angular rate sensing axis and a dither axis normal to each other and parallel to a plane of said substrate, secured within said support structure;
a mounting frame formed in said substrate;
a first and a second accelerometer formed in said substrate wherein each said accelerometer includes an accelerometer frame, a proof mass located within said accelerometer frame, a hinge attaching a first end of said proof mass to said accelerometer frame in order to permit at least limited angular rotation of said proof mass with respect to said accelerometer frame in response to acceleration in a force sensing axis normal to the plane of said substrate wherein said first and second proof masses are located on each side of and in parallel to said angular rate sensing axis, a first strut connecting a second end of said proof mass to said accelerometer frame, and a force detector connected between said proof mass and said accelerometer frame;
a plurality of frame flexures connecting said first and second accelerometer frames to said mounting frame;
dither means for dithering said first and second accelerometers along said dither axis at a frequency ω
;
processing means responsive to said first and second force detectors for generating a signal representing angular rotation of the sensor around said angular rate sensing axis, said processing means including means for generating a misalignment signal; and
means, responsive to said misalignment signal, for applying an alignment force to said first and second proof masses, said alignment force aligning each of said proof masses with said dither axis.
3 Assignments
0 Petitions
Accused Products
Abstract
An angular rate sensor that utilizes the Coriolis effect and which includes two dithered accelerometers having proof masses suspended by a hinge fabricated out of a Silicon substrate, the proof masses are provided with support struts that can be adjusted by applying heat to the struts to compensate for misalignment of the proof masses along the dither axis. In one embodiment, the hinges are located on the same side of the substrate and a vibrating beam force transducers are connected between each of the proof masses and associated accelerometer frames in a push-pull arrangement.
6 Citations
40 Claims
-
1. An angular rate sensor comprising:
-
a support structure; a generally planar substrate, having an angular rate sensing axis and a dither axis normal to each other and parallel to a plane of said substrate, secured within said support structure; a mounting frame formed in said substrate; a first and a second accelerometer formed in said substrate wherein each said accelerometer includes an accelerometer frame, a proof mass located within said accelerometer frame, a hinge attaching a first end of said proof mass to said accelerometer frame in order to permit at least limited angular rotation of said proof mass with respect to said accelerometer frame in response to acceleration in a force sensing axis normal to the plane of said substrate wherein said first and second proof masses are located on each side of and in parallel to said angular rate sensing axis, a first strut connecting a second end of said proof mass to said accelerometer frame, and a force detector connected between said proof mass and said accelerometer frame; a plurality of frame flexures connecting said first and second accelerometer frames to said mounting frame; dither means for dithering said first and second accelerometers along said dither axis at a frequency ω
;processing means responsive to said first and second force detectors for generating a signal representing angular rotation of the sensor around said angular rate sensing axis, said processing means including means for generating a misalignment signal; and means, responsive to said misalignment signal, for applying an alignment force to said first and second proof masses, said alignment force aligning each of said proof masses with said dither axis. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
-
-
20. An angular rate sensor comprising:
-
a support structure; a generally planar substrate, having an angular rate sensing axis and a dither axis normal to each other and parallel to a plane of said substrate, secured within said support structure; a mounting frame formed in said substrate; a first accelerometer formed in said substrate, located within said mounting frame on a first side of said angular rate sensing axis, including a first accelerometer frame, a first proof mass located within said first accelerometer frame, a first hinge attaching a first end of said first proof mass to said first accelerometer frame to permit at least limited angular rotation of said first proof mass with respect to a plane of said first accelerometer frame in response to acceleration along a force sensing axis normal to the plane of said substrate, a first suspension member connecting a second end of said first proof mass to said first accelerometer frame and first force detector connected between said first proof mass and said first accelerometer frame; a first frame flexure connecting said first accelerometer frame to said mounting frame; a second accelerometer formed in said substrate, located within said mounting frame on a second side of said angular rate sensing axis, including a second accelerometer frame, a second proof mass located within said second accelerometer frame, a second hinge attaching a first end of said second proof mass to said second accelerometer frame to permit at least limited angular rotation of said second proof mass with respect to a plane of said second accelerometer frame in response to acceleration along said force sensing axis, a second suspension member connecting a second end of said second proof mass to said second accelerometer frame and a second force detector connected between said second proof mass and said second accelerometer frame; a second frame flexure connecting said second accelerometer frame to said mounting frame; a link formed in said substrate connecting said first accelerometer to said second accelerometer; dither means for dithering said first and second accelerometers along said dither axis at a frequency ω
;processing means responsive to said first and second force detecting means and said dither means for generating an angular rotation signal representing the angular rotation of the sensor around said angular rate axis, and a misalignment signal; and means, coupled to receive said misalignment signal, for selectively applying an alignment force in response to said misalignment signal to each of said first and second proof masses, said alignment force aligning each of said first and second proof masses along said dither axis. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29)
-
-
30. A sensor comprising:
-
a support structure; a mounting frame secured in said support structure; a first planar proof mass; first suspension means including a first hinge for connecting said first proof mass to said mounting frame such that a plane of said proof mass is generally maintained parallel to both a first axis and a second axis which are normal to each other and is permitted by said hinge at least limited angular rotation with respect to said first axis in response to acceleration along a force sensing axis normal to both said first axis and said second axis; alignment force applying means for applying a first alignment force to said first proof mass through said first suspension means to maintain said proof mass in planar alignment with said second axis; and wherein said alignment force applying means includes a first misalignment signal means for generating a first misalignment signal and wherein said alignment force applying means generates said first alignment force in response to said first misalignment signal. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
-
Specification