Sensor
First Claim
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1. A device for sensing relative position or orientation of first and second members comprising a source of light having first and second color components;
- a filter having first and second portions respectively preferentially passing said first and second color components, and substantially fixed relative to the first member;
a mask, having first and second portions respectively relatively transparent to and opaque to both said first and second color components, and substantially fixed relative to the second member; and
a sensor for detecting the first and second color components, wherein;
the mask and the filter are mounted along one or more light paths between the source and sensor; and
a change in said position or orientation causes a varying relative occlusion of said first and second filter portions by said second mask portions so as to vary a relative proportion of said first and second color components detected by the sensor.
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Abstract
The relative position of two members is determined based upon a detected relative intensities of first and second colors of light. The intensity balance associated with relative occlusion of first and second color filter portions on one member by a mask on the other member. An exemplary use is in rotational position sensing within a limited rotation range. With a given compliance between the two members, the position sensing can be used as a proxy for torque sensing.
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Citations
17 Claims
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1. A device for sensing relative position or orientation of first and second members comprising
a source of light having first and second color components; -
a filter having first and second portions respectively preferentially passing said first and second color components, and substantially fixed relative to the first member;
a mask, having first and second portions respectively relatively transparent to and opaque to both said first and second color components, and substantially fixed relative to the second member; and
a sensor for detecting the first and second color components, wherein;
the mask and the filter are mounted along one or more light paths between the source and sensor; and
a change in said position or orientation causes a varying relative occlusion of said first and second filter portions by said second mask portions so as to vary a relative proportion of said first and second color components detected by the sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method for sensing a drive torque applied by a user to the handrim of a wheel chair comprising:
detecting a balance between first and second colors of light passed from a source through a mask and a filter, one of which is substantially fixed relative to the hand rim and the other of which is substantially fixed relative to a drive wheel associated with the hand rim, the relative orientation of the drive wheel and hand rim being indicative of said torque in view of a given compliance and the balance being indicative of the relative orientation of the filter and mask. - View Dependent Claims (17)
Specification