Apparatus and method for determining angular position and rotational speed using a rotating magnet and a directional magnetometer
First Claim
1. A method of determining the angular position, rotational speed, and/or acceleration of a rotatable member, comprising:
- (a) providing on said rotatable member an annular magnetic source generating tangential, radial, and axial magnetic flux field components;
(b) detecting, with a directional magnetometer having a toroidal core and two secondary output windings thereon, at a location radially spaced from said magnetic source, in proximity to said magnetic source, the amplitude(s) and/or change of amplitude(s) of one or more said magnetic flux field components, and providing outputs from said secondary output windings indicative thereof;
(c) modifying said outputs, to equalize measured peak amplitudes of said magnetic flux field components and/or to compensate for environmental distortion thereof, by orienting said toroidal core such that said toroidal core lies in a plane at an angle between the plane of said annular magnetic source and a plane perpendicular to said plane of said annular magnetic source; and
(d) determining from said outputs the angular position, rotational speed, and/or acceleration of said rotatable member.
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Accused Products
Abstract
A method of determining the angular position, rotational speed, and/or acceleration of a rotatable member, including: providing on the rotatable member an annular magnetic source generating tangential, radial, and axial magnetic flux field components; detecting, with a directional magnetometer having a toroidal core and two secondary output windings thereon, at a location radially spaced from the magnetic source, in proximity to the magnetic source, the amplitude(s) and/or change of amplitude(s) of one or more of the magnetic flux field components, and providing outputs indicative thereof; modifying the outputs, to equalize measured peak amplitudes of the magnetic flux field components and/or to compensate for environmental distortion thereof, by one or more methods selected from the group consisting of: (1) orienting the toroidal core such that the toroidal core lies in a plane at an angle between the plane of the annular magnetic source and a plane perpendicular to the plane of the annular magnetic source, (2) providing the secondary output windings with unequal numbers of turns, and (3) attentuating one of the outputs; and determining from the outputs the angular position, rotational speed, and/or acceleration of the rotatable member.
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Citations
5 Claims
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1. A method of determining the angular position, rotational speed, and/or acceleration of a rotatable member, comprising:
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(a) providing on said rotatable member an annular magnetic source generating tangential, radial, and axial magnetic flux field components; (b) detecting, with a directional magnetometer having a toroidal core and two secondary output windings thereon, at a location radially spaced from said magnetic source, in proximity to said magnetic source, the amplitude(s) and/or change of amplitude(s) of one or more said magnetic flux field components, and providing outputs from said secondary output windings indicative thereof; (c) modifying said outputs, to equalize measured peak amplitudes of said magnetic flux field components and/or to compensate for environmental distortion thereof, by orienting said toroidal core such that said toroidal core lies in a plane at an angle between the plane of said annular magnetic source and a plane perpendicular to said plane of said annular magnetic source; and (d) determining from said outputs the angular position, rotational speed, and/or acceleration of said rotatable member. - View Dependent Claims (2)
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3. An apparatus for detecting the angular position, rotational speed, and/or acceleration of a rotatable member, comprising:
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(a) an annular magnetic source circumferentially disposed on said rotatable member and rotatable therewith, said magnetic source generating tangential, radial, and axial magnetic flux field components; (b) a directional magnetometer, having a toroidal core with two secondary output windings thereon, disposed at a location, radially spaced from said magnetic source, in proximity to said magnetic source, said directional magnetometer being oriented so as to detect the amplitude(s) and/or change of amplitude(s) of one or more said magnetic flux field components, and to provide outputs from said secondary windings indicative thereof; (c) said outputs being modified, to equalize measured peak amplitudes of said magnetic flux field components and/or to compensate for environmental distortion thereof, by orienting said toroidal core such that said toroidal core lies in a plane at an angle between the plane of said annular magnetic source and a plane perpendicular to said plane of said annular magnetic source; and (d) means to receive said outputs and to determine therefrom the angular position, rotational speed, and/or acceleration of said rotatable member. - View Dependent Claims (4, 5)
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Specification