Sensing head positioning system using two-stage offset air bearings
First Claim
1. An apparatus for positioning a sensing head relative to a workpiece, the apparatus comprising:
- a control unit operative to provide a plurality of control signals to iteratively control positioning of the sensing head relative to the workpiece;
a plurality of air injectors disposed and fixedly connected on a periphery of the sensing head, each of the air injectors capable of being independently controlled to eject a gas between the sensing head and the workpiece to create an air bearing and affect positioning of the sensing head relative to the workpiece in response to at least one of the control signals; and
a plurality of sensors capable of providing a plurality of feedback signals to the control unit, the feedback signals containing information relating to positioning of an optical imaging sensing head relative to the workpiece.
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Accused Products
Abstract
Methods, apparatuses, and systems are presented for positioning a sensing head relative to a workpiece, involving a control unit operative to provide a plurality of control signals to iteratively control positioning of the sensing head relative to the workpiece, a plurality of air injectors disposed and fixedly connected on a periphery of the sensing head, each of the air injectors capable of being independently controlled to eject a gas between the sensing head and the workpiece to create an air bearing and affect positioning of the sensing head relative to the workpiece in response to at least one of the control signals, and a plurality of sensors providing a plurality of feedback signals to the control unit, the feedback signals containing information relating to positioning of an optical imaging sensing head relative to the workpiece.
12 Citations
27 Claims
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1. An apparatus for positioning a sensing head relative to a workpiece, the apparatus comprising:
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a control unit operative to provide a plurality of control signals to iteratively control positioning of the sensing head relative to the workpiece;
a plurality of air injectors disposed and fixedly connected on a periphery of the sensing head, each of the air injectors capable of being independently controlled to eject a gas between the sensing head and the workpiece to create an air bearing and affect positioning of the sensing head relative to the workpiece in response to at least one of the control signals; and
a plurality of sensors capable of providing a plurality of feedback signals to the control unit, the feedback signals containing information relating to positioning of an optical imaging sensing head relative to the workpiece. - View Dependent Claims (2)
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3. An apparatus for positioning a sensing head relative to a workpiece, the apparatus comprising:
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a control unit operative to provide a plurality of control signals to iteratively control positioning of the sensing head relative to the workpiece;
a plurality of air injectors disposed and fixedly connected on a periphery of the sensing head, the air injectors capable of ejecting a gas between the sensing head and the workpiece to create an air bearing and affect positioning of the sensing head relative to the workpiece in response to at least one of the control signals;
a plurality of sensors capable of providing a plurality of feedback signals to the control unit, the feedback signals containing information relating to positioning of an optical imaging sensing head relative to the workpiece; and
wherein the control unit is further operative to map readings received from the sensors from a sensor-space representation to a virtual-sensor-space representation before forming an output-to-movement relationship such that an inverse of an output-to-movement relationship is more likely to be obtainable.
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4. An apparatus for positioning a sensing head relative to a workpiece, the apparatus comprising:
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a plurality of first air injectors fixedly connected with the sensing head;
a plurality of second air injectors fixedly connected with the sensing head;
a plurality of sensors providing a plurality of feedback signals, the feedback signals containing information relating to positioning of the sensing head relative to the workpiece; and
a control unit receiving the plurality of feedback signals from the sensors and controlling the first and second air injectors, the control unit capable of bringing positioning of the sensing head relative to the workpiece within a desired range by iteratively adjusting the first air injectors, the control unit being capable of adding an additional separation distance to positioning of the sensing head relative to the workpiece by operating the second air injectors.
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5. An apparatus for positioning a sensing head relative to a workpiece, the apparatus comprising:
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a plurality of sensors operative to detect a reading of positioning of the sensing head relative to the workpiece;
a plurality of air injectors fixedly connected with the sensing head, each of the air injectors capable of ejecting a gas with a variably controllable output level between the sensing head and the workpiece in order to affect positioning of the sensing head relative to the workpiece; and
a control unit operative to receive the reading from the sensors and to control the air injectors, the control unit being capable of locating the sensing head relative to the workpiece within a desired range, said locating comprising;
(a) varying the output level of each air injector by a small amount and noting a resulting change in the reading received from the sensors in order to form an output-to-movement relationship;
(b) applying an inverse of the output-to-movement relationship to the reading received from the sensors in order to calculate a plurality of output adjustments;
(c) adjusting the output levels of the air injectors by the output adjustments; and
(d) repeating (a) through (c) until positioning of the sensing head relative to the workpiece is within the desired range. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for positioning a sensing head relative to a workpiece, the method comprising the steps of:
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detecting, using a plurality of sensors, a reading of positioning of the sensing head relative to the workpiece;
ejecting from a plurality of air injectors fixedly connected with the sensing head a gas between the sensing head and the workpiece in order to affect positioning of the sensing head relative to the workpiece; and
locating the sensing head relative to the workpiece within a desired range, said locating comprising;
(a) varying an output level of each air injector by a small amount and noting a resulting change in the reading received from the sensors in order to form an output-to-movement relationship;
(b) applying an inverse of the output-to-movement relationship to the reading received from the sensors in order to calculate a plurality of output adjustments;
(c) adjusting the output levels of the air injectors by the output adjustments; and
(d) repeating (a) through (c) until positioning of the sensing head relative to the workpiece is within the desired range. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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21. A system for positioning a sensing head relative to a workpiece, the system comprising:
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means for detecting a reading of positioning of the sensing head relative to the workpiece using a plurality of sensors;
means for ejecting from a plurality of air injectors fixedly connected with the sensing head a gas between the sensing head and the workpiece in order to affect positioning of the sensing head relative to the workpiece; and
means for locating the sensing head relative to the workpiece within a desired range, said locating comprising;
(a) varying an output level of each air injector by a small amount and noting a resulting change in the reading received from the sensors in order to form an output-to-movement relationship;
(b) applying an inverse of the output-to-movement relationship to the reading received from the sensors in order to calculate a plurality of output adjustments;
(c) adjusting the output levels of the air injectors by the output adjustments; and
(d) repeating (a) through (c) until positioning of the sensing head relative to the workpiece is within the desired range. - View Dependent Claims (22, 23, 24, 25, 26, 27)
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Specification