Micromachined rate and acceleration sensor
First Claim
1. An angular rate sensor comprising:
- a) a generally planar substrate, having an angular rate sensing axis and a vibration axis normal to each other and parallel to a plane of said substrate;
b) a mounting frame formed in said substrate;
c) a first accelerometer formed in said substrate and located within said mounting frame on a first side of said angular rate sensing axis, said first accelerometer includinga first accelerometer frame,a first proof mass located within said first accelerometer frame,a first flexure rotatably attaching a first end of said first proof mass to said first accelerometer frame,a first suspension member connecting a second end of said first proof mass to said first accelerometer frame, anda first force detector connected between said first proof mass and said first accelerometer frame;
d) a second accelerometer formed in said substrate, located within said mounting frame on a second side of said angular rate sensing axis, said second accelerometer includinga second accelerometer frame,a second proof mass located within said second accelerometer frame,a second flexure rotatable attaching a first end of said second proof mass to said second accelerometer frame,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;
e) a first and second frame flexure connecting said first and second accelerometer frames to said mounting frame;
f) a link member mechanically coupling said first accelerometer to said second accelerometer;
g) vibration means for vibrating said first and second accelerometers along said vibration axis at a predetermined frequency; and
h) processing means responsive to said first and second force detectors for generating an angular rotation signal representing the angular rotation of the sensor about said angular rate axis.
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Accused Products
Abstract
A sensor (10) is disclosed for measuring the specific force and angular rotation rate of a moving body and is micromachined from a silicon substrate (16). First and second accelerometers (32a and b) are micromachined from the silicon substrate (16), each having a force sensing axis (38) and producing an output signal of the acceleration of the moving body along its force sensing axis (38). The first and second accelerometers (32a and b) are mounted within the substrate (16) to be moved along a vibration axis (41). The first and second accelerometers (32a and b) are vibrated or dithered to increase the Coriolis component of the output signals from the first and second accelerometers (32a and b). A sinusoidal drive signal of a predetermined frequency is applied to a conductive path (92) disposed an each of the accelerometers. Further, magnetic flux is directed to cross each of the conductive paths (92), whereby the interaction of the magnetic flux and of the drive signal passing therethrough causes the desired dithering motion. A link (72) is formed within the silicon substrate (16) and connected to each of the accelerometers (32a and b), whereby motion imparted to one results in a like, but opposite motion applied to the other accelerometer (32). Further, a unitary magnet (20) and its associated flux path assembly direct and focus the magnetic flux through the first and second accelerometers (32a and b) formed within the silicon substrate (16).
8 Citations
4 Claims
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1. An angular rate sensor comprising:
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a) a generally planar substrate, having an angular rate sensing axis and a vibration axis normal to each other and parallel to a plane of said substrate; b) a mounting frame formed in said substrate; c) a first accelerometer formed in said substrate and located within said mounting frame on a first side of said angular rate sensing axis, said first accelerometer including a first accelerometer frame, a first proof mass located within said first accelerometer frame, a first flexure rotatably attaching a first end of said first proof mass to said first accelerometer frame, a first suspension member connecting a second end of said first proof mass to said first accelerometer frame, and a first force detector connected between said first proof mass and said first accelerometer frame; d) a second accelerometer formed in said substrate, located within said mounting frame on a second side of said angular rate sensing axis, said second accelerometer including a second accelerometer frame, a second proof mass located within said second accelerometer frame, a second flexure rotatable attaching a first end of said second proof mass to said second accelerometer frame, 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; e) a first and second frame flexure connecting said first and second accelerometer frames to said mounting frame; f) a link member mechanically coupling said first accelerometer to said second accelerometer; g) vibration means for vibrating said first and second accelerometers along said vibration axis at a predetermined frequency; and h) processing means responsive to said first and second force detectors for generating an angular rotation signal representing the angular rotation of the sensor about said angular rate axis. - View Dependent Claims (2, 3, 4)
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Specification