Dithering coriolis rate and acceleration sensor utilizing a permanent magnet
First Claim
1. A sensor for measuring angular rate and linear acceleration of a body on which the sensor is mounted, comprising:
- rotor means mounted on a base plate for oscillating dithering motion about a dither axis extending through the base plate;
accelerometer means carried by the rotor means and having a sensitive axis that is perpendicular to the direction of dither motion and perpendicular to a prime axis relative to which angular rate is to be measured;
electromagnet dither drive means operatively associated with the rotor means for effecting the dithering motion of the rotor means;
velocity sensing pick-off coil means operatively associated with the rotor means for providing a signal representative of the angular velocity about the dither axis; and
single permanent magnet means carried by the base plate for providing a flux field to interact with the electromagnet dither drive means to provide the electromotive force for effecting the dithering motion of the rotor means, and to provide lines of flux which are cut by the velocity sensing pick-off coil means for producing the velocity sensing signal.
3 Assignments
0 Petitions
Accused Products
Abstract
A sensor (10) for measuring angular rate and linear acceleration of a body, in which first and second rotors (30, 31), each carrying a plurality of accelerometers (44, 49), are mounted for counter-rotating dithering motion on opposite sides of a base plate (11). A single permanent magnet (70) is mounted centrally of the base plate, with one pole (71) disposed adjacent the first rotor and the other pole (72) disposed adjacent the second rotor. First and second X-shaped pole pieces (80, 81) are mounted at the respective opposite poles of the magnet, and a plurality of velocity sensing pick-off coils (86) are mounted on the arms (82, 83, 84 and 85) of the pole pieces for cooperation with flux splitting protrusions (34, 35 and 36) on the rotors. The arms of the pole pieces are associated with the flux splitting protrusions so that differential flux splitting is obtained as the rotors are rotated in opposite directions. The accelerometers are arranged in opposed pairs on the respective rotors so that their sensitive axes are parallel to one another but point in opposite directions for canceling common mode error signals, and they are carried on rotor arms (40, 41, 42 and 45, 46 and 47) that converge toward one another from opposite sides of the base plate, so that the accelerometer centers of percussion are spaced closely together and at the same dither radius to minimize cross-axis error signals. A differential torque dither drive for the rotors comprises a plurality of electromagnet coils (19, 20) carried by the base plate for cooperation with armatures (37, 38 and 39) on the rotors to simultaneously rotate the rotors in opposite directions, and a sinusoidally varying energizing current effects opposite or reverse operation.
78 Citations
19 Claims
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1. A sensor for measuring angular rate and linear acceleration of a body on which the sensor is mounted, comprising:
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rotor means mounted on a base plate for oscillating dithering motion about a dither axis extending through the base plate; accelerometer means carried by the rotor means and having a sensitive axis that is perpendicular to the direction of dither motion and perpendicular to a prime axis relative to which angular rate is to be measured; electromagnet dither drive means operatively associated with the rotor means for effecting the dithering motion of the rotor means; velocity sensing pick-off coil means operatively associated with the rotor means for providing a signal representative of the angular velocity about the dither axis; and single permanent magnet means carried by the base plate for providing a flux field to interact with the electromagnet dither drive means to provide the electromotive force for effecting the dithering motion of the rotor means, and to provide lines of flux which are cut by the velocity sensing pick-off coil means for producing the velocity sensing signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. In a sensor for measuring angular rate and linear acceleration of a body on which the sensor is mounted, said sensor including first and second rotors carried on opposite sides of a base plate for counter-rotating dithering motion about a dither axis extending through the base plate, dither drive means for dithering the rotors, accelerometer means carried by the rotors for sensing angular rate and linear acceleration and producing a signal in response thereto, velocity sensing pick-off coils associated with the rotors for detecting angular motion of the rotors and producing a signal in response thereto, and signal processing means for processing the signals to obtain a measure of the angular rate and linear acceleration, the improvement comprising:
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permanent magnet means carried by the base plate and having one pole disposed adjacent one rotor and the other pole disposed adjacent the other rotor; a pole piece mounted at each pole of the magnet means, each said pole piece having a plurality of arms projecting radially outwardly over the adjacent rotor, and on each of which a velocity sensing coil is mounted; and said rotors having flux splitting means thereon for cooperation with the arms and associated coils on the pole pieces so that differential flux splitting is obtained as the rotors are dithered with respect to the pole pieces. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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Specification