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US 6,534,970 B1Granted
Rotary position sensor and transducer for use therein
AssigneeSynaptics (UK) Limited
InventorsDavid T. E. Ely, Ross P. Jones
Life of this patent
Estimating the term…
Abstract
A rotary position detector includes first and second members, the first member generating a magnetic field which spatially varies around the axis of rotation in a cyclic manner and the second member sensing the generated magnetic field. In response to the generated magnetic field, first and second signals are generated by first and second sensors respectively, which signals vary with the relative angular position of the first and second members and the relative angular position of the first and second members is determined from the first and second signals.
Claims72
A rotary position detector, comprising:
- first and second members, at least one of which is rotatable relative to the other about an axis of rotation;
- said first member comprising:
- (a) a first magnetic field generator for generating a magnetic field which spatially varies around said axis of rotation in a cyclic manner with an angular frequency of M;
- and
- (b) a second magnetic field generator comprising a winding which is wound around said axis of rotation and which has a plurality of loop portions circumferentially spaced around said axis of rotation, for generating a magnetic field which spatially varies around said axis of rotation in a cyclic manner and which comprises a fundamental component with an angular frequency of N and harmonic components thereof,
- wherein N<M and wherein the circumferential spacing between said loop portions is arranged so as to reduce the amount of predetermined ones of the harmonic components generated by said second magnetic field generator;
- said second member comprising:
- (a) a first sensor which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of M;
- and
- (b) a second sensor which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of N;
- whereby, in response to a magnetic field being generated by said first and second magnetic field generators, first and second signals are generated by said first and second sensors respectively, which signals vary with the relative angular position of said first and second members;
- and
- means for determining the relative angular position of said first and second members from said first and second signals.
10 more elements
A rotary position detector, comprising:
- first and second members, at least one of which is rotatable relative to the other about an axis of rotation;
- said first member comprising:
- (a) a first magnetic field generator for generating a magnetic field which spatially varies around said axis of rotation in a cyclic manner with an angular frequency of M;
- and
- (b) a second magnetic field generator comprising a winding which is wound around said axis of rotation and which has a plurality of loop portions circumferentially spaced around said axis of rotation, for generating a magnetic field which spatially varies around said axis of rotation in a cyclic manner and which comprises a fundamental component with an angular frequency of N and some harmonic components thereof,
- wherein N<M and wherein the circumferential spacing between said loop portions is arranged so as to try to eliminate predetermined ones of said harmonic components generated by said second magnetic field generator;
- said second member comprising:
- (a) a first sensor which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of M;
- and
- (b) a second sensor which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of N;
- whereby, in response to a magnetic field being generated by said first and second magnetic field generators, first and second signals are generated by said first and second sensors respectively, which signals vary with the relative angular position of said first and second members;
- and
- means for determining the relative angular position of said first and second members from said first and second signals.
10 more elements
A rotary position detector, comprising:
- first and second members, at least one of which is rotatable relative to the other about an axis of rotation;
- said first member comprising:
- (a) a first magnetic field generator for generating a magnetic field which spatially varies around said axis of rotation in a cyclic manner with an angular frequency of M;
- and
- (b) a second magnetic field generator comprising a winding which is wound around said axis of rotation and which has a plurality of loop portions circumferentially spaced around said axis of rotation, for generating a magnetic field which spatially varies around said axis of rotation in a cyclic manner and which comprises a fundamental component with an angular frequency of N and some harmonic components thereof,
- wherein N<M and wherein the circumferential spacing between said loop portions is arranged so as to reduce the amount of some of the harmonic components generated by said second magnetic field generator, relative to the amount of said harmonic components which exist in a corresponding square wave signal;
- said second member comprising:
- (a) a first sensor which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of M;
- and
- (b) a second sensor which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of N;
- whereby, in response to a magnetic field being generated by said first and second magnetic field generators, first and second signals are generated by said first and second sensors respectively, which signals vary with the relative angular position of said first and second members;
- and
- means for determining the relative angular position of said first and second members from said first and second signals.
10 more elements
A rotary position detector, comprising:
- first and second members, at least one of which is rotatable relative to the other about an axis of rotation;
- said first member comprising:
- (a) a first magnetic field generator for generating a magnetic field which spatially varies around said axis of rotation in a cyclic manner with an angular frequency of M;
- and
- (b) a second magnetic field generator comprising a winding which is wound around said axis of rotation and which has a plurality of loop portions circumferentially spaced around said axis of rotation, for generating a magnetic field which spatially varies around said axis of rotation in a cyclic manner and which comprises a fundamental component with an angular frequency of N and some harmonic components thereof,
- wherein N<M and wherein the circumferential spacing between said loop portions is arranged so as to reduce the amount of the harmonic components generated by said second magnetic field generator which have an angular frequency of M±1;
- said second member comprising:
- (a) a first sensor which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of M;
- and
- (b) a second sensor which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of N;
- whereby, in response to a magnetic field being generated by said first and second magnetic field generators, first and second signals are generated by said first and second sensors respectively, which signals vary with the relative angular position of said first and second members;
- and
- means for determining the relative angular position of said first and second members from said first and second signals.
10 more elements
A rotary position detector, comprising:
- first and second members, at least one of which is rotatable relative to the other about an axis of rotation;
- said first member comprising:
- (a) a first magnetic field generator for generating a magnetic field which spatially varies around said axis of rotation in a cyclic manner with an angular frequency of M;
- and
- (b) a second magnetic field generator comprising a winding which is wound around said axis of rotation and which has a plurality of loop portions circumferentially spaced around said axis of rotation, for generating a magnetic field which spatially varies around said axis of rotation in a cyclic manner and which comprises a fundamental component with an angular frequency of N and some harmonic components thereof,
- wherein N<M and wherein the circumferential spacing between said loop portions is arranged so as to eliminate the harmonic components generated by said second magnetic field generator which have an angular frequency of M±1;
- said second member comprising:
- (a) a first sensor which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of M;
- and
- (b) a second sensor which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of N;
- whereby, in response to a magnetic field being generated by said first and second magnetic field generators, first and second signals are generated by said first and second sensors respectively, which signals vary with the relative angular position of said first and second members;
- and
- means for determining the relative angular position of said first and second members from said first and second signals.
10 more elements
A transducer for use in a rotary position detector, comprising:
- (a) a first magnetic field generator for generating a magnetic field which spatially varies around an axis in a cyclic manner with an angular frequency of M;
- (b) a second magnetic field generator comprising a winding which is wound around said axis and which has a plurality of loop portions circumferentially spaced around said axis of rotation, for generating a magnetic field which spatially varies around said axis in a cyclic manner and which comprises a fundamental component with an angular frequency of N and some harmonic components thereof,
- wherein N<M and wherein the circumferential spacing between said loop portions is arranged so as to reduce the amount of some of the harmonic components generated by said second magnetic field generator;
- (c) a first sensor which is sensitive to magnetic fields which spatially vary around said axis in a cyclic manner and with an angular frequency of M;
- and
- (d) a second sensor which is sensitive to magnetic fields which spatially vary around said axis in a cyclic manner and with an angular frequency of N.
3 more elements
A transducer for use in a rotary position detector, comprising:
- a first circuit board comprising at least two layers of conductor tracks which are connected together at a plurality of vias to form:
- (a) a first winding which, when energised, is operable for generating a magnetic field which spatially varies around an axis of the circuit board in a cyclic manner and with an angular frequency of M;
- and
- (b) a second winding which is wound around said axis and which has a plurality of loop portions circumferentially spaced around said axis of rotation, which winding is operable, when energised, for generating a magnetic field which spatially varies around said axis in a cyclic manner and which comprises a fundamental component with an angular frequency of N and some harmonic components thereof,
- wherein N<M and wherein the circumferential spacing between said loop portions is arranged so as to reduce the amount of some of the harmonic components which are generated by said second winding when it is energised;
- and
- a second circuit board comprising at least two layers of conductor tracks which are connected together at a plurality of vias to form:
- (a) a first sensor winding which is wound around an axis of the second circuit board in a cyclic manner so as to have a sensitivity to magnetic fields which spatially vary around said axis with an angular frequency of M;
- and
- (b) a second sensor winding which is wound around said axis in a cyclic manner so as to have a sensitivity to magnetic fields which spatially vary around said axis with an angular frequency of N.
7 more elements
A method of detecting the position of first and second members, at least one of which is rotatable relative to the other about an axis of rotation, the method comprising the steps of:
- providing on the first member (a) a first magnetic field generator for generating a magnetic field which spatially varies around said axis of rotation in a cyclic manner with an angular frequency of M;
- and (b) a second magnetic field generator comprising a winding which is wound around said axis of rotation and which has a plurality of loop portions circumferentially spaced around said axis of rotation, for generating a magnetic field which spatially varies around said axis of rotation in a cyclic manner and which comprises a fundamental component with an angular frequency of N and harmonic components thereof,
- wherein N<M and wherein the circumferential spacing between said loop portions is arranged so as to reduce the amount of predetermined ones of the harmonic components generated by said second magnetic field generator;
- providing on said second member (a) a first sensor which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of M;
- and (b) a second sensor which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of N;
- generating a magnetic field with said first and second magnetic field generators;
- sensing the magnetic fields generated by said first and second magnetic field generators with said sensors, to generate first and second signals which vary with the relative angular position of the first and second members;
- and
- determining the relative angular position of said first and second members from said first and second signals.
6 more elements
A rotary position detector, comprising:
- first and second members, at least one of which is rotatable relative to the other about an axis of rotation;
- said first member comprising:
- (a) a first magnetic field generator operable to generate a magnetic field which spatially varies around said axis of rotation in a cyclic manner with an angular frequency of M;
- and
- (b) a second magnetic field generator comprising a winding which is wound around said axis of rotation and which has a plurality of loop portions circumferentially spaced around said axis of rotation, and operable to generate a magnetic field which spatially varies around said axis of rotation in a cyclic manner and which comprises a fundamental component with an angular frequency of N and harmonic components thereof,
- wherein N<M and wherein the circumferential spacing between said loop portions is arranged so as to reduce the amount of predetermined ones of the harmonic components generated by said second magnetic field generator;
- said second member comprising:
- (a) a first sensor which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of H;
- and
- (b) a second sensor which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of N;
- wherein, in response to a magnetic field being generated by said first and second magnetic field generators, first and second signals are generated by said first and second sensors respectively, which signals vary with the relative angular position of said first and second members;
- and
- a position processor operable to process said first and second signals to determine the relative angular position of said first and second members.
10 more elements
A rotary position detector, comprising:
- first and second members, at least one of which is rotatable relative to the other about an axis of rotation;
- said first member comprising:
- (a) a first magnetic field generator operable to generate a magnetic field which spatially varies around said axis of rotation in a cyclic manner with an angular frequency of N;
- and
- (b) a second magnetic field generator comprising a winding which is wound around said axis of rotation and which has a plurality of loop portions circumferentially spaced around said axis of rotation, operable to generate a magnetic field which spatially varies around said axis of rotation in a cyclic manner and which comprises a fundamental component with an angular frequency of N and some harmonic components thereof,
- wherein N<M and wherein the circumferential spacing between said loop portions is arranged so as to try to eliminate predetermined ones of said harmonic components generated by said second magnetic field generator;
- said second member comprising:
- (a) a first sensor which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of M;
- and
- (b) a second sensor which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of N;
- wherein, in response to a magnetic field being generated by said first and second magnetic field generators, first and second signals are generated by said first and second sensors respectively, which signals vary with the relative angular position of said first and second members;
- and
- a position processor operable to determine the relative angular position of said first and second members using said first and second signals.
10 more elements
A rotary position detector, comprising:
- first and second members, at least one of which is rotatable relative to the other about an axis of rotation;
- said first member comprising:
- (a) a first magnetic field generator operable to generate a magnetic field which spatially varies around said axis of rotation in a cyclic manner with an angular frequency of M;
- and
- (b) a second magnetic field generator comprising a winding which is wound around said axis of rotation and which has a plurality of loop portions circumferentially spaced around said axis of rotation, and operable to generate a magnetic field which spatially varies around said axis of rotation in a cyclic manner and which comprises a fundamental component with an angular frequency of b˜ and some harmonic components thereof,
- wherein N<M and wherein the circumferential spacing between said loop portions is arranged so as to reduce the amount of some of the harmonic components generated by said second magnetic field generator, relative to the amount of said harmonic components which exist in a corresponding square wave signal;
- said second member comprising;
- (a) a first sensor which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of M;
- and
- (b) a second sensor which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of N;
- wherein, in response to a magnetic field being generated by said first and second magnetic field generators, first and second signals are generated by said first and second sensors respectively, which signals vary with the relative angular position of said first and second members;
- and
- a position processor operable to determine the relative angular position of said first and second members using said first and second signals.
10 more elements
A rotary position detector, comprising:
- first and second members, at least one of which is rotatable relative to the other about an axis of rotation;
- said first member comprising:
- (a) a first magnetic field generator operable to generate a magnetic field which spatially varies around said axis of rotation in a cyclic manner with an angular frequency of M;
- and
- (b) a second magnetic field generator comprising a winding which is wound around said axis of rotation and which has a plurality of loop portions circumferentially spaced around said axis of rotation, and operable to generate a magnetic field which spatially varies around said axis of rotation in a cyclic manner and which comprises a fundamental component with an angular frequency of N and some harmonic components thereof, wherein N<M and wherein the circumferential spacing between said loop portions is arranged so as to reduce the amount of the harmonic components generated by said second magnetic field generator which have an angular frequency of N±1;
- said second member comprising:
- (a) a first sensor which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of M;
- (b) a second sensor which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of N;
- wherein, in response to a magnetic field being generated by said first and second magnetic field generators, first and second signals are generated by said first and second sensors respectively, which signals vary with the relative angular position of said first and second members;
- and
- a position processor operable to determine the relative angular position of said first and second members from said first and second signals.
8 more elements
A rotary position detector, comprising:
- first and second members, at least one of which is rotatable relative to the other about an axis of rotation;
- said first member comprising:
- (a) a first magnetic field generator operable to generate a magnetic field which spatially varies around said axis of rotation in a cyclic manner with an angular frequency of M;
- and
- (b) a second magnetic field generator comprising a winding which is wound around said axis of rotation and which has a plurality of loop portions circumferentially spaced around said axis of rotation, and operable to generate a magnetic field which spatially varies around said axis of rotation in a cyclic manner and which comprises a fundamental component with an angular frequency of N and some harmonic components thereof,
- wherein N<M and wherein the circumferential spacing between said loop portions is arranged so as to eliminate the harmonic components generated by said second magnetic field generator which have an angular frequency of M±1;
- said second member comprising:
- (a) a first sensor which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of M;
- and
- (b) a second sensor which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of N;
- wherein, in response to a magnetic field being generated by said first and second magnetic field generators, first and second signals are generated by said first and second sensors respectively, which signals vary with the relative angular position of said first and second members;
- and
- a position processor operable to determine the relative angular position of said first and second members from said first and second signals.
10 more elements
A transducer for use in a rotary position detector, comprising:
- (a) a first magnetic field generator operable to generate a magnetic field which spatially varies around an axis in a cyclic manner with an angular frequency of
- (b) a second magnetic field generator comprising a winding which is wound around said axis and which has a plurality of loop portions circumferentially spaced around said axis of rotation, and operable to generate a magnetic field which spatially varies around said axis n a cyclic manner and which comprises a fundamental component with an angular frequency of N and some harmonic components thereof,
- wherein N<M and wherein the circumferential spacing between said loop portions is arranged so as to reduce the amount of some of the harmonic components generated by said second magnetic field generator;
- c) a first sensor which is sensitive to magnetic fields which spatially vary around said axis in a cyclic manner and with an angular frequency of M;
- and
- (d) a second sensor which is sensitive to magnetic fields which spatially vary around said axis in a cyclic manner and with an angular frequency of N.
3 more elements
A transducer for use in a rotary position detector, comprising:
- a first circuit board comprising at least two layers of conductor tracks which are connected together at a plurality of vias to form;
- (a) a first winding which, when energised, is operable to generate a magnetic field which spatially varies around an axis of the circuit board in a cyclic manner and with an angular frequency of M;
- and
- (b) a second winding which is wound around said axis and which has a plurality of loop portions circumferentially spaced around said axis of rotation,
- which second winding is operable, when energised, to generate a magnetic field which spatially varies around said axis in a cyclic manner and which comprises a fundamental component with an angular frequency of N and some harmonic components thereof,
- wherein N<M and wherein the circumferential spacing between said loop portions is arranged so as to reduce the amount of some of the harmonic components which are generated by said second winding when it is energised;
- and
- a second circuit board comprising at least two layers of conductor tracks which are connected together at a plurality of vias to form:
- (a) a third winding which is wound around an axis of the second circuit board in a cyclic manner so as to have a sensitivity to magnetic fields which spatially vary around said axis with an angular frequency of M;
- and
- (b) a fourth winding which is wound around said axis in a cyclic manner so as to have a sensitivity to magnetic fields which spatially vary around said axis with an angular frequency of N.
8 more elements
A rotary position detector, comprising:
- first and second members, at least one of which is rotatable relative to the other about an axis of rotation;
- said first member comprising:
- (a) a first magnetic field generator operable to generate a magnetic field which spatially varies around said axis of rotation in a cyclic manner with an angular frequency of M;
- and
- (b) a second magnetic field generator comprising a winding which is wound around said axis of rotation and which has a plurality of loop portions circumferentially spaced around said axis of rotation, and operable to generate a magnetic field which spatially varies around said axis of rotation in a cyclic manner and which comprises a fundamental component with an angular frequency of N and harmonic components thereof,
- wherein N<M and wherein the circumferential spacing between said loop portions is arranged so as to reduce the amount of predetermined ones of the harmonic components generated by said second magnetic field generator;
- said second member comprising:
- (a) a first winding which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of M;
- and
- (b) a second winding which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner and with an angular frequency of N;
- wherein, in response to a magnetic field being generated by said first and second magnetic field generators, first and second signals are generated by said first and second windings respectively, which signals vary with the relative angular position of said first and second members;
- and
- a position processor operable to process said first and second signals to determine the relative angular position of said first and second members.
10 more elements
A transducer for use in a rotary position detector, comprising:
- (a) a first magnetic field generator operable to generate a magnetic field which spatially varies around an axis in a cyclic manner with an angular frequency of M;
- and
- (b) a second magnetic field generator comprising a winding which is wound around said axis and which has a plurality of loop portions circumferentially spaced around said axis of rotation, and operable to generate a magnetic field which spatially varies around said axis in a cyclic manner and which comprises a fundamental component with an angular frequency of N and some harmonic components thereof,
- wherein N<M, and wherein the circumferential spacing between said loop portions is non-uniform and is arranged so as to reduce the amount of some of the harmonic components generated by said second magnetic field generator, relative to the amount of said harmonic components which exist in a corresponding square wave signal.
1 more element
A rotary position detector, comprising:
- first and second members, at least one of which is rotatable relative to the other about an axis of rotation;
- said first member comprising:
- (a) a first magnetic field generator operable to generate a magnetic field which spatially varies around said axis of rotation in a cyclic manner with an angular frequency of H;
- and
- (b) a second magnetic field generator comprising a winding which is wound around said axis of rotation and
- which has a plurality of loop portions circumferentially spaced around said axis of rotation, and operable to generate a magnetic field which spatially varies around said axis of rotation in a cyclic manner and which comprises a fundamental component with an angular frequency of N and harmonic components thereof,
- wherein N<M and wherein the circumferential spacing between said loop portions is non-uniform and arranged so as to reduce the amount of predetermined ones of the harmonic components generated by said second magnetic field generator relative to the amount of said harmonic components which exist in a corresponding square wave signal;
- said second member comprising:
- (a) a first excitation winding which is operable to generate a magnetic field which spatially varies around said axis of rotation in a cyclic manner and with an angular frequency of H for energising said first magnetic field generator;
- (b) a second excitation winding which is operable to generate a magnetic field which spatially varies around said axis of rotation in a cyclic manner with an angular frequency of N, for energising said second magnetic field generator;
- and
- (c) a sensor winding which is sensitive to magnetic fields which spatially vary around said axis of rotation in a cyclic manner with an angular frequency of N and M;
- wherein upon excitation by said first and second excitation windings, first and second signals are generated by said sensor winding, which signals vary with the relative angular position of said first and second members;
- and
- a position processor operable to process said first and second signals to determine the relative angular position of said first and second members.
12 more elements
Dependencies are inferred from the claim text.