Inductive position sensor with common mode corrective winding and simplified signal conditioning
First Claim
1. An apparatus for providing an output signal correlated with a part position for a moveable part, the part position having a positional range, the positional range being divisible into segments, the apparatus comprising:
- a transmitter coil, the transmitter coil generating electromagnetic radiation when excited by an exciter signal;
a plurality of receiver coils located proximate to the transmitter coil, each receiver coil generating a receiver signal when the transmitter coil is excited due to inductive coupling between the transmitter coil and the receiver coils;
a coupler element, having a coupler element position correlated with the part position, the inductive coupling between the transmitter coil and each receiver coil being sensitive to the coupler element position;
a reference coil, providing a reference signal substantially independent of the part position;
a signal conditioner receiving the receiver signals and the reference signal, and providing an output signal correlated with the position of the moveable part, the output signal being derived from a selected receiver signal, the selected receiver signal being selected according to the segment of the positional range, the signal conditioner including an analog divider, the selected receiver signal being divided by the reference signal in the analog divider so as to eliminate common mode noise effects from the output signal.
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Accused Products
Abstract
An inductive position sensor for rotary motion includes a transmitter coil and a receiver coil, the receiver coil generating a receiver signal when the transmitter coil is excited by an alternating current source. A moveable coupler element modifies the inductive coupling between the transmitter coil and the receiver coil so that the receiver signal is sensitive to the coupler element position. The ratio between the receiver signal and the reference signal is sensitive to the coupler element position, but substantially insensitive to common mode factors. The angular or positional range of the position sensor can be increased using a plurality of receiver coils.
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Citations
26 Claims
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1. An apparatus for providing an output signal correlated with a part position for a moveable part, the part position having a positional range, the positional range being divisible into segments, the apparatus comprising:
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a transmitter coil, the transmitter coil generating electromagnetic radiation when excited by an exciter signal;
a plurality of receiver coils located proximate to the transmitter coil, each receiver coil generating a receiver signal when the transmitter coil is excited due to inductive coupling between the transmitter coil and the receiver coils;
a coupler element, having a coupler element position correlated with the part position, the inductive coupling between the transmitter coil and each receiver coil being sensitive to the coupler element position;
a reference coil, providing a reference signal substantially independent of the part position;
a signal conditioner receiving the receiver signals and the reference signal, and providing an output signal correlated with the position of the moveable part, the output signal being derived from a selected receiver signal, the selected receiver signal being selected according to the segment of the positional range, the signal conditioner including an analog divider, the selected receiver signal being divided by the reference signal in the analog divider so as to eliminate common mode noise effects from the output signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 24)
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19. An apparatus for providing an output signal correlated with a part position for a moveable part, the part position having a positional range, the apparatus comprising:
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a transmitter coil, the transmitter coil generating electromagnetic radiation when excited by an exciter signal;
a first receiver coil providing a first receiver signal;
a second receiver coil producing a second receiver signal;
a coupler element, having a coupler element position correlated with the part position, the an inductive coupling between the transmitter coil and each receiver coil being sensitive to the coupler element position; and
a reference coil, providing a reference signal substantially independent of the coupler element position; and
a signal conditioner, receiving the first and second receiver signals and providing an output signal correlated with the position of the moveable part, the output signal being derived from the first receiver signal over a first segment of the positional range, and from the second receiver signal over a second segment of the positional range. - View Dependent Claims (20, 21, 22, 23)
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25. A method of determining the position of a moveable part, the method comprising:
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exciting a transmitter coil;
obtaining a plurality of receiver signals from a plurality of receiver coils;
selecting a chosen receiver signal according to the approximate position of the moveable part;
obtaining a reference signal substantially independent of the position of the moveable part, the reference signal and the chosen receiver signal being subject to common noise factors;
dividing the selected receiver signal by the reference signal in an analog divider circuit to provide a ratiometric signal so as to eliminate the common noise factors; and
determining the position of the moveable part using the ratiometric signal. - View Dependent Claims (26)
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Specification