Position encoder
First Claim
1. An inductive position encoder comprising:
- first and second members which are relatively moveable over a measurement path;
a magnetic device mounted on the first member;
a plurality, n, of first windings mounted on the second member; and
a second winding;
wherein said magnetic device is operable to interact with said windings such that upon the energisation of one of;
i) said second winding and ii) said first windings, there is generated a plurality of sensor signals in the other one of said second winding and said first windings, each sensor signal being associated with a respective one of said first windings and varying with the relative position between said magnetic device and the associated first winding and hence with the relative position between said first and second members;
wherein each first winding comprises a plurality of loops sequentially arranged along the measurement path and the loops of each first winding being connected in series so that each first winding is substantially balanced with respect to the background interference;
wherein at least one of said first windings comprises a series of loops arranged along the measurement path;
wherein said plurality of first windings are arranged to define less than 2n zones sequentially arranged along the measurement path in accordance with a predetermined non-repeating code so that said plurality of sensor signals vary with the relative position of said first and second members in accordance with said predetermined non-repeating code; and
wherein said plurality of first windings are arranged along said measurement path so that over at least the majority of said zones, said sensor signals vary in accordance with a predetermined Gray code.
1 Assignment
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Accused Products
Abstract
An inductive position encoder is described having first and second members which are relatively moveable over a measurement path, a magnetic device mounted on the first member; a plurality of first windings mounted on the second member; and a second winding. The magnetic device is operable to interact with the windings such that upon the energization of either the second winding or the first windings, there is generated a plurality of sensor signals each being associated with a respective one of said first windings and varying with the relative position between said magnetic device and the associated first winding and hence with the relative position between said first and second members. Additionally, the plurality of first windings are arranged along said measurement path so that the sensor signals vary substantially in accordance with a predetermined Gray code.
38 Citations
36 Claims
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1. An inductive position encoder comprising:
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first and second members which are relatively moveable over a measurement path; a magnetic device mounted on the first member; a plurality, n, of first windings mounted on the second member; and a second winding; wherein said magnetic device is operable to interact with said windings such that upon the energisation of one of;
i) said second winding and ii) said first windings, there is generated a plurality of sensor signals in the other one of said second winding and said first windings, each sensor signal being associated with a respective one of said first windings and varying with the relative position between said magnetic device and the associated first winding and hence with the relative position between said first and second members;wherein each first winding comprises a plurality of loops sequentially arranged along the measurement path and the loops of each first winding being connected in series so that each first winding is substantially balanced with respect to the background interference; wherein at least one of said first windings comprises a series of loops arranged along the measurement path; wherein said plurality of first windings are arranged to define less than 2n zones sequentially arranged along the measurement path in accordance with a predetermined non-repeating code so that said plurality of sensor signals vary with the relative position of said first and second members in accordance with said predetermined non-repeating code; and wherein said plurality of first windings are arranged along said measurement path so that over at least the majority of said zones, said sensor signals vary in accordance with a predetermined Gray code. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 32, 33, 34, 35, 36)
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28. An odometer comprising:
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a plurality of rotatable dials sequentially positioned adjacent each other and arranged so that as each dial rotates through one revolution, a subsequent dial in the sequence rotates through a part of a revolution; a corresponding plurality of non-contact position sensing transducers, each non-contact position sensing transducer being located adjacent the corresponding dial between that dial and an adjacent dial in the sequence, and each comprising one or more excitation windings and one or more receive windings; wherein each dial carries a magnetic device positioned adjacent the corresponding position sensing transducer and operable to interact with said windings such that upon the energisation of said one or more excitation windings there is generated in the one or more receive windings sensor signals that vary with the angular position of the corresponding dial; and wherein the windings mounted on each position sensing transducer have a position sensing range and wherein said dials and said position sensing transducers are arranged so that the magnetic device carried by each dial is within the position sensing range of the windings of the corresponding position sensing transducer, but outside the position sensing range of the windings of the other position sensing transducers wherein each dial has a diameter of between 15 mm and 25 mm and is separated from adjacent dials by a distance of between 4 mm and 7 mm. - View Dependent Claims (29, 30, 31)
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Specification