Engineering topics
Publications and source records attributed to Smith, Matthew A..
Photodetector or optical fiber leading to photodetector mounted inside gas/tungsten arc welding torch to monitor arc light reflected from oscillating surface of weld pool. Proposed optical monitoring components preserve compact profile of welding torch, maintained in fixed aim at weld-pool position at end of welding torch, and protected against bumping external objects.
Video/computer subsystem of welding system produces overlay, on video image, containing numerical data on parameters of welding operation being viewed. Operator watches weld bead simultaneously with instantaneous values of such data as elapsed time, welding current, and processed sensor measurements of weld area. Pertinent weld data always available to viewer and correlated in time with image of weld.
Proposed subsystem of tungsten/inert-gas (TIG) welding system measures length of welding arc optically. Viewed by video camera, in one of three alternative optical configurations. Length of arc measured instead of inferred from voltage.
Proposed tool measures alignments of plates before butt-welded. Provides nearly instantaneous check on alignment, thereby facilitating repetitive measurements along length of weld joint. Reduces risk of contamination of weld from dirty measuring tools. Middle photodetector indicates acceptable alignment when position of transmitter fiber preciously matches that of center receiver fiber. If plates offset, other photodetectors signal misalignment.
Optoelectronic sensor measures both position and direction of incidence of laser beam or other narrow beam of light. New sensor part of robotic welding system in which laser beam reflected from pool of molten metal and monitored by lateral-position sensor. To provide unambiguous measurement of both lateral position and direction of incident beam, sensor includes two position-sensitive photodetectors or linear arrays of photodetectors.
Electronic motor-speed control circuit designed to operate in electrically noisy environment. Includes optoelectronic pick-up device, placed inside motor housing to provide speed feedback signal. Automatically maintains speed motor at commanded value. Measures speed of motor in terms of frequency of pulses of infrared light chopped by fan blades of motor. Difference between measured and commanded speeds serves as control signal for external amplifier driving motor. Major advantage of circuit is low cost.
Breaks in optical fibers reveal failures in duct walls. Group of optical fibers wrapped around duct carries light beams from lasers to photodiodes. Break in duct breaks fiber bonded to it, interrupting path of light between laser and photodetector. Interruption used to command shutdown of engine or other system to minimize damage.