• Journal of Sensor Science and Technology
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• v.28 no.6
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• pp.414-419
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• 2019

An ultrasonic based magnetostrictive position sensor (MPS) provides an indication of real target position. It determines the real target position by multiplying the propagation speed of ultrasonic wave and the time-of-flight between the receiving signals; one is the initial signal by an excitation current and the other is the reflection signal by the ultrasonic wave. The propagation speed of the ultrasonic wave depends on the temperature of the waveguide. Hence, the change of the propagation speed in various environments is a critical factor in terms of the positioning accuracy in the MPS. This means that the influence of the changes in the waveguide temperature needs to be compensated. In this paper, we presents a novel way to improve the positioning accuracy of MPSs using temperature compensation for waveguide. The proposed method used the inherent measurement blind area for the structure of the MPS, which can simultaneously measure the position of the moving target and the temperature of the waveguide without any additional devices. The average positional error was approximately -23.9 mm and -1.9 mm before and after compensation, respectively. It was confirmed that the positioning accuracy was improved by approximately 93%.

• Journal of Magnetics
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• v.20 no.4
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• pp.439-443
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• 2015

A control rod drive mechanism (CRDM) is an electromechanical equipment that provides linear movement for the control rods to control the nuclear reactivity in a nuclear reactor. A rod position indication system (RPIS) detects the control rod's position. To enhance the measurement accuracy of the system, a magnetostrictive type sensor with capability of generating operation limiting signals would be adapted instead of a conventional RPIS for a CRDM. An RPIS was modelled for a numerical analysis with the permanent magnets at the stationary limit positions and magnetic shielding plates with a moving permanent magnet. The performance analysis of the RPIS were conducted, and the results were discussed here.

• Journal of the Korea Safety Management & Science
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• v.2 no.1
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• pp.89-97
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• 2000

This paper shows the study for development inprocess measuring magnetic sensor for tolerance control, First, we fabricated and annealed sample amorphous ribbons which were made of ($CO_{0.94}$$Fe_{0.06}$)$_{79}$$Si_{2}$$b_{19}$ having near zero magnetostrictive. It had 12［$\mu\textrm{m}$］ of thickness, 10［mm］ of length, and 2.5［mm］ of width. Then, we measured the magnetic characteristics such as frequency dependency over impedance variation rate and position change over impedance variation. As the results of the evaluation, we found that the sample ribbons had excellent sensor characteristics. Then, we made sensors by using the sample ribbons, As the results of the measurements, it proved that the ribbon could be used as excellent magnetic sensor for which it was possible to control inprocess measurement within the tolerance range(~$\mu\textrm{m}$ ).