Seam tracker for automatic welder
First Claim
1. A welding system for welding along a weld seam, comprising:
- a welding torch;
a drive mechanism for advancing the welding torch along the weld seam;
a controllable lateral torch drive mechanism for driving the welding torch laterally of the weld seam;
means for producing reflected electromagnetic radiation from the weld seam in an unimaged spatial distribution having an optical center of power functionally related to the lateral positioning of the welding torch relative to the weld seam; and
means for sensing a shift in position of the optical center of power of the reflected electromagnetic radiation produced by a variation in the spatial distribution of the reflected radiation resulting from lateral deviation of the welding torch relative to the weld seam and producing a control input to the lateral torch drive mechanism in response thereto.
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Accused Products
Abstract
Apparatus for non-contact tracking of a weld seam to provide lateral position guidance of a welding torch advanced along the weld seam by a traveling carriage utilizes an electromagnetic radiation source for directing an unfocused beam onto the weld seam producing a spatial distribution of reflected electromagnetic radiation having an optical center of power the location of which is functionally related to the lateral position of the welding torch relative to the weld seam, and a lateral cell position sensor for sensing a shift in position of the optical center of power of the reflected electromagnetic radiation spatial distribution. Detection of a shift in position of the optical center of power is utilized as an indication of lateral deviation of the welding torch relative to the weld seam.
The apparatus disclosed further includes signal processing circuitry that develops an electrical signal indicative of welding torch position for input to a torch drive servomechanism. The signal processing circuitry includes noise rejection circuitry to suppress torch light effects on the position sensor and circuitry to reject the RF characteristic of the welding ARC.
30 Citations
18 Claims
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1. A welding system for welding along a weld seam, comprising:
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a welding torch; a drive mechanism for advancing the welding torch along the weld seam; a controllable lateral torch drive mechanism for driving the welding torch laterally of the weld seam; means for producing reflected electromagnetic radiation from the weld seam in an unimaged spatial distribution having an optical center of power functionally related to the lateral positioning of the welding torch relative to the weld seam; and means for sensing a shift in position of the optical center of power of the reflected electromagnetic radiation produced by a variation in the spatial distribution of the reflected radiation resulting from lateral deviation of the welding torch relative to the weld seam and producing a control input to the lateral torch drive mechanism in response thereto. - View Dependent Claims (2, 3, 4, 5)
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6. Apparatus for guiding a welding torch to track a weld seam, comprising:
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an electromagnetic radiation source for directing an unfocused beam of electromagnetic radiation onto the weld seam; a lateral cell position sensor receiving unimaged electromagnetic radiation reflected from the weld seam for sensing lateral position deviations of the welding torch relative to the weld seam; and means connected to the sensor for producing a signal representative of torch position with respect to the center of the weld seam. - View Dependent Claims (7, 8, 9)
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10. A welding system for welding along a weld seam, comprising:
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a welding torch; a drive mechanism for advancing the welding torch along the weld seam; a controllable lateral torch drive mechanism for driving the welding torch laterally of the weld seam; a source of electromagnetic radiation disposed proximate the welding torch and advanced along therewith, the electromagnetic radiation source directing a narrow beam of unfocused electromagnetic radiation from the weld seam in an unimaged spatial distribution having an optical center of power functionally related to the lateral positioning of the welding torch relative to the weld seam; a position sensor spaced from the electromagnetic radiation source and oriented to receive reflected electromagnetic radiation from the weld seam for detecting the optical center of power of the reflected electromagnetic radiation and sensing a shift in position of the optical center of power produced by a variation of the reflected radiation resulting from lateral deviation of the welding torch relative to the weld seam, the position sensor providing an electrical output signal indicative of the position of the optical center of power; and signal processing circuitry receiving the electrical output signal of the position sensor and producing in response thereto a control input to the lateral torch drive mechanism. - View Dependent Claims (11, 12, 13)
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14. Apparatus for tracking a weld seam and providing guidance of a welding torch, which comprises:
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a drive mechanism for moving the welding torch bidirectionally across the weld seam; a housing mounted in fixed relation to the welding torch for movement therewith; a light source carried in the housing, the light source emitting a beam of unfocused light directed onto the weld seam; a position sensor carried in the housing and spaced apart from the light source for receiving unimaged light reflected from the weld seam and producing first and second electrical output signals in response to the spatial distribution of the reflected light falling on the sensor; signal processing circuitry connected to the position sensor for developing from the first and second electrical output signals a signal representative of the lateral position of the welding torch relative to the weld seam; and means for applying the torch lateral position signal as an input to the torch drive mechanism.
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15. Apparatus for controlled movement of a welding torch to weld along a weld seam, which comprises:
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a reversible drive motor linked to the welding torch for moving the same bidirectionally across the weld seam; a torch oscillator providing an oscillatory output signal for directing movement of the torch across the weld seam; a torch position sensor linked to the drive motor for providing an output signal indicative of torch position relative to the center of oscillation thereof; a manually adjustable device for providing an electrical signal effect to drive the motor and permit initial centering of the welding torch to the weld seam; and a non-contact optical seam tracker for providing an output signal indicative of the center of torch oscillatory movement relative to the weld seam, the seam tracker sensing lateral positioning of the torch relative to the weld seam using a beam of light reflected from the weld seam; a summing circuit for receiving as control inputs to the torch drive mechanism the torch oscillator signal, the torch position sensor signal, the torch center adjustment signal, and the seam tracker signal and producing therefrom a motor control signal; and a power driver for applying electrical power to the drive motor in response to the motor control signal.
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16. A method of non-contact tracking of a weld seam by a welding torch controlled by a drive mechanism comprising the steps of:
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producing an unimaged spatial distribution of electromagnetic radiation reflected from the weld seam having an optical center of power functionally related to the lateral position of the welding torch relative to the weld seam; receiving the unimaged electromagnetic radiation reflected from the weld seam with a sensor that detects a shift in position of the optical center of power that results from lateral deviation of the welding torch relative to the weld seam and produces an output signal indicative of a shift in center of power position; and processing the output signal from the sensor to develop a control signal for input to the torch drive mechanism.
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17. A welding system for welding along a weld seam, comprising:
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a welding torch; a drive mechanism for advancing the welding torch along the weld seam; a controllable lateral drive torch drive mechanism for moving the welding torch laterally of the weld seam; means for producing reflected electromagnetic radiation from the weld seam; means for producing reflected electromagnetic radiation from the weld seam in an unimaged spatial distribution having an optical center of power functionally related to the lateral positioning of the welding torch relative to the weld seam; and a single element phototransducer for sensing a shirt in position of the optical center of power of the reflected electromagnetic radiation produced by a variation in the spatial distribution of the reflected radiation resulting from lateral deviation of the welding torch relative to the weld seam and producing a control input to the lateral torch drive mechanism in response thereto.
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18. A welding system for welding along a weld seam, comprising:
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a welding torch; a drive mechanism for advancing the welding torch along the weld seam; a controllable lateral drive torch drive mechanism for moving the welding torch laterally of the weld seam; means for producing reflected electromagnetic radiation from the weld seam; a source of electromagnetic radiation disposed proximate the welding torch and advanced along therewith, the electromagnetic radiation source directing a narrow beam of unfocused electromagnetic radiation from the weld seam in an unimaged spatial distribution having an optical center of power functionally related to the lateral positioning of the welding torch relative to the weld seam; a single element phototransducer spaced from the electromagnetic radiation source and oriented to receive reflected electromagnetic radiation from the weld seam for detecting the optical center of power of the reflected electromagnetic radiation and sensing a shift in position of the optical center of power produced by a variation of the reflected radiation resulting from lateral deviation of the welding torch relative to the weld seam, the transducer providing an electrical output signal indicative of the position of the optical center of power; and signal processing circuitry receiving the electrical output signal of the transducer and producing in response thereto a control input to the lateral torch drive mechanism.
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Specification