Sensor apparatus and method for sensing angular rotation of an object using light reflected off a rotor and bifurcation compensation
First Claim
1. An apparatus for sensing angular rotation comprising:
- a mounting member;
a rotor rotatably mounted to the member and rotatable about an axis, said rotor having an outer periphery with a plurality of reflective facets, a juncture between each adjacent pair of facets defining an associated vertex, the plurality of reflective facets forming vertices;
a light source fixed relative to the member for emitting a light beam onto said rotor, the light beam from said light source being reflected by said facets and, during relative rotation between said rotor and the member, the reflected light beam being occasionally bifurcated by said vertices;
a light detector fixed relative to the member for detecting the reflected light beam and providing a detector signal indicative of relative angular rotation between said rotor and the member and bifurcation of the emitted light beam; and
compensation circuitry including filter means responsive to the detector signal for compensating for the bifurcation of the emitted light beam and for providing a signal indicative of the instantaneous relative rate of angular rotation between said rotor and the member.
2 Assignments
0 Petitions
Accused Products
Abstract
An apparatus (100) for sensing angular rotation includes a rotor (102) that is rotatable about an axis (104). The rotor (102) has an outer periphery (e.g., cylindrical outer sidewall 106) with a plurality of reflective facets (e.g., 108A-108J). Each juncture between each adjacent pair of the facets (e.g., 108A and 108B) defines a vertex (e.g., 125A). A light source (118) emits a light beam (120) onto the rotor (102). The light beam (120) is reflected by the facets (e.g., 108B) and occasionally bifurcated by the vertices (e.g., 125A). A light detector (126) detects light from the reflected light (124). The light detector (126) provides a detector signal (116) indicative of the angular rotation of the rotor (102). Compensation circuitry (134, 138) compensates for bifurcation of the reflected light (124) and provides a compensated output signal (140) indicative of angular rotation of the rotor (102).
33 Citations
22 Claims
-
1. An apparatus for sensing angular rotation comprising:
-
a mounting member;
a rotor rotatably mounted to the member and rotatable about an axis, said rotor having an outer periphery with a plurality of reflective facets, a juncture between each adjacent pair of facets defining an associated vertex, the plurality of reflective facets forming vertices;
a light source fixed relative to the member for emitting a light beam onto said rotor, the light beam from said light source being reflected by said facets and, during relative rotation between said rotor and the member, the reflected light beam being occasionally bifurcated by said vertices;
a light detector fixed relative to the member for detecting the reflected light beam and providing a detector signal indicative of relative angular rotation between said rotor and the member and bifurcation of the emitted light beam; and
compensation circuitry including filter means responsive to the detector signal for compensating for the bifurcation of the emitted light beam and for providing a signal indicative of the instantaneous relative rate of angular rotation between said rotor and the member. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
-
-
16. A rollover sensor for a vehicle comprising:
-
a rotor rotatable about an axis and having an outer periphery with a plurality of reflective facets, each juncture between each adjacent pair of facets defining a vertex;
a light source that emits a light beam onto said rotor, the light beam from said light source being reflected by said facets and occasionally bifurcated by said vertices;
a light detector that detects the reflected light and that provides a detector signal indicative of angular rotation of said rotor and the bifurcation;
compensation circuitry responsive to the detector signal that compensates for the bifurcation and provides a compensated output signal indicative of angular rotation of said rotor; and
a controller that determines an angular velocity of the vehicle based on the compensated output signal, said controller determining a vehicle rollover condition based on the determined angular velocity of the vehicle and wherein said compensation circuitry includes a differentiator to differentiate the detector signal and a filter that filters the differentiated detector signal and provides a first signal indicative of a time-averaged component of the differentiated detector signal, which is indicative of angular velocity of said rotor, and the first signal is subtracted from at least part of the differentiated detector signal to define the compensated output signal. - View Dependent Claims (17)
-
-
18. A method for sensing angular rotation of an object, said method comprising the steps of:
-
mounting a rotor for rotation relative to the object responsive to movement of the object, the rotor having an outer periphery with a plurality of reflective members, a juncture between each adjacent pair of the reflective members defining an associated vertex, the plurality of reflective members forming vertices;
emitting a beam onto said rotor, the emitted beam being reflected by the reflective members and during relative rotation between the rotor and the object, the reflected beam being occasionally bifurcated by the vertices;
detecting the reflected light and providing a detector signal indicative of relative angular rotation between the rotor and the object and bifurcation of the beam; and
filtering the detector signal for compensating for the bifurcation and providing a compensated output signal indicative of the instantaneous relative rate of angular rotation between the rotor and the object. - View Dependent Claims (19, 20, 21, 22)
-
Specification