Method and apparatus for correcting attenuation in an optical torque sensor
First Claim
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1. A torque sensor for determining the torque acting upon a shaft, the torque sensor comprising:
- a radiation source emitting radiation of at least one wavelength;
at least one sensor sensing the emitted radiation generating thereby at least one intensity signal indicative of the intensity of the emitted radiation;
at least one signal conditioner receptive of the emitted radiation and positioned on a shaft between the radiation source and the at least one sensor thereby conditioning the emitted radiation;
a circuit receptive of the at least one intensity signal determining thereby the torque acting upon the shall and compensating for the attenuation of the emitted radiation;
wherein the at least one signal conditioner comprises a plurality of polarizers having polarization axes oriented at prescribed angle with respect to one another; and
wherein the plurality of polarizers are substantially opaque to radiation at the first wavelength and substantially transparent to radiation at the second wavelength.
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Abstract
An optical torque sensor comprises a radiation source emitting radiation of at least one wavelength. At least one sensor senses the emitted radiation and generates at least one intensity signal indicative of the intensity of the emitted radiation. At least one signal conditioner is receptive of the emitted radiation and is positioned on a shaft between the radiation source and the at least one sensor thereby conditioning the emitted radiation. A circuit is receptive of the at least one intensity signal and determines the torque acting upon the shaft and compensates for the attenuation of the emitted radiation.
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Citations
34 Claims
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1. A torque sensor for determining the torque acting upon a shaft, the torque sensor comprising:
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a radiation source emitting radiation of at least one wavelength;
at least one sensor sensing the emitted radiation generating thereby at least one intensity signal indicative of the intensity of the emitted radiation;
at least one signal conditioner receptive of the emitted radiation and positioned on a shaft between the radiation source and the at least one sensor thereby conditioning the emitted radiation;
a circuit receptive of the at least one intensity signal determining thereby the torque acting upon the shall and compensating for the attenuation of the emitted radiation;
wherein the at least one signal conditioner comprises a plurality of polarizers having polarization axes oriented at prescribed angle with respect to one another; and
wherein the plurality of polarizers are substantially opaque to radiation at the first wavelength and substantially transparent to radiation at the second wavelength. - View Dependent Claims (2, 3, 4, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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5. A method of compensating for signal attenuation in a sensor sensing the torque acting upon a shaft, the method comprising:
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generating radiation of at least one wavelength;
conditioning the radiation;
sensing the radiation;
responsive to the sensed radiation, generating at least one intensity signal indicative of the intensity of the radiation;
determining the intensity of the radiation due to a combination of the torque acting upon the shaft and the contamination of the sensor;
determining the intensity of the radiation due to the contamination of the sensor only; and
calculating the difference between the intensity of the radiation due to a combination of the torque acting upon the shaft and the contamination of the sensor and the intensity of the radiation due to the contamination of the sensor only to generate a compensated signal indicative only of the torque acting upon the shaft. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13)
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14. A torque sensor for determining the torque acting upon a shaft, the torque sensor comprising:
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a radiation source emitting radiation of at least one wavelength;
at least one sensor sensing the emitted radiation generating thereby at least one intensity signal indicative of the intensity of the emitted radiation;
at least one signal conditioner receptive of the emitted radiation and positioned on a shaft between the radiation source and the at least one sensor thereby conditioning the emitted radiation;
a circuit receptive of the at least one intensity signal determining thereby the torque acting upon the shaft and compensating for the attenuation of the emitted radiation; and
wherein the radiation source comprises a plurality of parallel light emitting diodes having alternate anodes connected either to electrical ground or energized by a prescribed voltage and alternate cathodes connected either to electrical ground or energized by the prescribed voltage.
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Specification