| CPC G01B 7/003 (2013.01) [G01D 5/2086 (2013.01)] | 20 Claims |
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1. A linear inductive position sensor, comprising:
an excitation coil extending along an axis of a substrate, the excitation coil generating a first electromagnetic field in response to an alternating current (AC) signal received from a power source;
a target coil configured to move above the excitation coil and along the axis, the target coil inductively coupled to the excitation coil and generating a second electromagnetic field;
a first sensor extending along the axis, the first sensor including a first receiver coil and a second receiver coil inductively coupled to the target coil so as to generate a first voltage in the first receiver coil and a second voltage in the second receiver coil depending on a position of the target coil relative to the axis, the first receiver coil being separated from the second receiver coil by a distance based on a period λ of the first receiver coil; and
a first processor coupled to the first sensor, the first processor configured to generate a position signal based on the first voltage and the second voltage, the position signal representing the position of the target coil.
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16. A linear inductive position sensor, comprising:
an excitation coil extending along an axis of a substrate;
a target coil configured to move above the excitation coil and along the axis, the target coil inductively coupled to the excitation coil when the excitation coil is provided with an alternating current, the target coil having a width;
a first sensor having a first plurality of receiver coils offset from one another by a distance λ, each receiver coil of the first plurality of receiver coils being inductively coupled to the target coil and including a first plurality of twisted loops, wherein a first twisted loop of the first plurality of twisted loops is offset from a second twisted loop of the first plurality of twisted loops by a first distance;
a second sensor having a second plurality of receiver coils offset from one another by a distance λ2, each receiver coil of the second plurality of receiver coils being inductively coupled to the target coil and including a second plurality of twisted loops, wherein a first twisted loop of the second plurality of twisted loops is offset from a second twisted loop of the second plurality of twisted loops by a second distance;
a first processor configured to generate a first position signal representing a position of the target coil, from a first set of voltages induced in the first plurality of receiver coils;
a second processor configured to generate a second position signal representing a position of the target coil, from a second set of voltages induced in the second plurality of receiver coils; and
a processor coupled to the first processor and the second processor, the processor configured to generate a final position signal using a Vernier principle, the final position signal representing a position of the target coil that is based on the first position signal X1 and the second position signal.
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20. A method, comprising:
receiving a first position signal from a first processor, the first position signal representing a position of a target coil, based on a first set of voltage signals generated by a first sensor;
receiving a second position signal from a second processor, the second position signal representing a position of the target coil, based on a second set of voltage signals generated by a second sensor; and
determining the position of the target coil from the first position signal and the second position signal using a Vernier principle, wherein
third harmonics are cancelled from the first set of voltage signals,
fifth harmonics are cancelled from the second set of voltage signals, and
the target coil is sized to nullify seventh harmonics from at least one of the first set of voltage signals and the second set of voltage signals.
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