Multi axis angular rate sensor having a single dither axis
First Claim
1. Apparatus for producing an output signal indicative of the angular rate of rotation of a body about a prime axis, comprising:
- (a) a first accelerometer and a second accelerometer, each having an acceleration sensitive axis and operative to produce a signal proportional to an acceleration directed along said axis, the first and second accelerometers being mounted on opposed support members that are pivotally connected to the body, the acceleration sensitive axes of the first and second accelerometers being generally aligned in parallel;
(b) a motor connected to counter-rotate the opposed support members about a common pivot axis, rotation of the body about the prime axis subjecting the counter-rotating accelerometers to a Coriolis acceleration that is a function of said angular rate of rotation and causing the accelerometers to produce a signal proportional to a component of the Coriolis acceleration that is aligned with their acceleration sensitive axes; and
(c) means for combining the signals produced by the first and the second accelerometers to produce the output signal indicative of said angular rate of rotation of the body about the prime axis.
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Accused Products
Abstract
A Coriolis rate sensor for determining both angular rate and linear acceleration with respect to three orthogonal axes. A first embodiment of the rate sensor (10) includes three pairs of accelerometers (26, 28, and 30) mounted on counter-rotating frame members (20, 22). The accelerometers are mounted with their sensitive axes antiparallel with each other, forming an acute angle with the common axis (40) about which the upper and lower frame members are counter-rotated back and forth in a dither motion. The upper and lower frame members are connected to a baseplate (12) by flex links (32), which are aligned radially about the axis. The flex links provide a relatively rigid support (in compression) between the frame members and the centrally disposed baseplate, yet readily permit counter-rotation of the two frame members. A link (56) prevents all but relative rotational movement between the frame members and baseplate. A pair of electromagnetic coils (42) and pole pieces (50) provide a sinusoidal driving force to counter-rotate the upper and lower frame members relative to each other to ensure that the upper and lower frame members are directly coupled to each other and to the baseplate. In a second embodiment of the rate sensor (100), eight accelerometers (102, 104, 106 and 108) are mounted with two pairs on an upper counter-rotating member and two pairs on a lower counter-rotating member.
70 Citations
47 Claims
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1. Apparatus for producing an output signal indicative of the angular rate of rotation of a body about a prime axis, comprising:
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(a) a first accelerometer and a second accelerometer, each having an acceleration sensitive axis and operative to produce a signal proportional to an acceleration directed along said axis, the first and second accelerometers being mounted on opposed support members that are pivotally connected to the body, the acceleration sensitive axes of the first and second accelerometers being generally aligned in parallel; (b) a motor connected to counter-rotate the opposed support members about a common pivot axis, rotation of the body about the prime axis subjecting the counter-rotating accelerometers to a Coriolis acceleration that is a function of said angular rate of rotation and causing the accelerometers to produce a signal proportional to a component of the Coriolis acceleration that is aligned with their acceleration sensitive axes; and (c) means for combining the signals produced by the first and the second accelerometers to produce the output signal indicative of said angular rate of rotation of the body about the prime axis. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. Apparatus for sensing an angular rate of rotation about each of a plurality of prime axes, comprising:
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(a) a supporting base; (b) a first frame member and a second frame member pivotally connected to the supporting base, so as to rotate about a common axis; (c) a plurality of pairs of accelerometers, each accelerometer having an acceleration sensitive axis, each pair of accelerometers being associated with one of the plurality of prime axes about which the angular rate of rotation is sensed, the pairs of accelerometers being mounted on the first and the second frame members so that the acceleration sensitive axes of the two accelerometers comprising a pair are generally in parallel alignment; (d) driving means, for counter-rotating the first frame member about the common axis relative to the second frame member, causing each accelerometer to rotate about the common axis, and causing each pair of accelerometers to be subjected to a Coriolis acceleration proportional to the angular rate of rotation about the prime axis with which it is associated so that each accelerometer produces an output signal that is a function of said Coriolis acceleration; and (e) signal processing means, connected to the pairs of accelerometers, for processing the output signals produced by the accelerometers to determine the angular rate of rotation about each of the prime axes. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A method for producing an output signal indicative of the angular rate of rotation of a body about a plurality of prime axes, comprising the steps of:
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(a) mounting a plurality of accelerometer pairs so that an acceleration sensitive axis of each accelerometer in the pair is generally parallel to that of the other, the accelerometers being operative to produce a signal proportional to an acceleration directed along their sensitive axes; (b) counter-rotating the accelerometer pairs on a first and a second frame member, about a common pivot axis; and (c) combining the signals produced by the pairs of accelerometers to produce a vector sum signal corresponding to each prime axis, said vector sum being proportional to the angular rate of rotation of the body about said prime axis. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47)
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Specification