Inventive Performance Improvement of Integrated Optical Rate Sensor Usint TIPS/TRIZ
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Engineering topics
Publications and source records attributed to Youmans, Bruce R..
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The Theory of Inventive Problem Solving (TIPS or also known as TRIZ) is a new scientific approach to innovative improvements of products and processes. This methodology was applied to inventively improve performance of an Integrated Optic Rate Sensor (IORS).
Optical/electronic system senses rotation and emits pulses at angular increments. System provides linear scale factor across wide range of rotation rates with no lockup at null. Design needs analog-to-digital converters with elaborate signal-processing circuits. Light from laser diode split evenly into two beams propagating in opposite directions around rotation-sensing coil of optical-fiber waveguide. Beams acquire phase difference proportional to rotation rate as they pass through coil. After emerging from coil, beams recombine in beam splitter, and coherent sum led to photodiode.
An improved optical gyroscope is provided, of the type that passes two light components in opposite directions through an optic fiber coil, and which adds a small variable frequency to one of the light components to cancel the phase shift due to rotation of the coil. The amount of coil rotation from an initial orientation, is accurately determined by combining the two light components, one of which has a slightly increased frequency, to develop beats that each represent a predetermined angle of rotation. The direction of rotation is obtained by combining the two light components on a photodetector, intermittently phase shifting a single light component by 90 deg and comparing the direction of change of photodetector output (+ or -) caused by the 90 deg shift, with the slope (+ or -) of the photodetector output at about the same time, when there is a 90 deg shift.
An all-fiber, 1.3-micron passive optical rotation sensor utilizing 4.2 km of single-mode fiber and synchronous detection has been constructed and tested in the laboratory. rms noise-equivalent rotation rates of 0.005 deg/hr have been measured. Drift and scale-factor variations resulted in a change in the indicated rotation rate of 0.4 deg/hr over a 1-hr time period.