• Journal of Sensor Science and Technology
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• v.18 no.3
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• pp.197-201
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• 2009

This paper studies on the noncontact displacement sensor system to detect the displacement of the cylinder rod. For an inexpensive and a simple process, magnetic scales are printed on the cylinder rod, and magnetized by the specially designed magnetizer that has an yoke through the alternation of N and S pole. Noncontact displacement sensor system consists of cylinder with magnetic scales, Hall sensor, linear guide, controller and display. The system can detect the displacement of moving cylinder with 5 cm/sec in the case of 1 mm magnetic scale. It shows a possibility of position detection of hydraulic cylinder and air cylinder.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1063-1066
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• 2003

A flow-meter and its measurement controller was developed for a hydraulic system. This study, for development of positive displacement flow-meter, consist of PIC(Peripheral Interface Controller) controller with MR(Magneto-resistive) sensors. This flow-meter is used valve position indicator for valve control system by hydraulic. The MR sensors are used for the rotation of OVAL gear that detecting device. In the ship environments, consideration that necessary explosive proof. Thus electro device or electro flow-meter needs explosion design for electric circuit. We designed noncontact type flow-meter and evaluated the safety and measuring abilities.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.8
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• pp.40-47
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• 2001

Optical measurement methods make it possible to detect object displacements with high resolution and noncontact measurements. Also, they are very robust against EMI noises and have long operation range. An optical triangulation sensor is one of widely used displacement measurement sensors for its sub-micron resolution, fast response, simple structure, and low cost. However. there are several errors caused by inclinations of a surface. speckle effects, power fluctuations of light sources, and noises of detectors. In this paper, in order to minimize error effects, we performed error analysis and proposed a new structure. Then, we setup a new modeling method and verify it through simulations and experiments. Based on the new model. we propose a new sensor structure and establish design criteria. Finally, we design a signal processing system to overcome a resolution-limited problem of light detectors. The resolution of the proposed system is 0.2${\mu}{\textrm}{m}$ in 5mm operating range.

• ETRI Journal
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• v.36 no.3
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• pp.361-366
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• 2014

In this paper, a new, simple capacitive tilt sensor with a metallic ball is proposed. The proposed tilt sensor has only two electrodes and a metallic ball, and this design assists in managing the inherent contact problem in measuring tilt angles. Capacitive sensing, compared with other types of tilt sensor, has many advantages such as simplicity, noncontact measurement, long-throw linear displacement, and sub-micron plate spacing. Its design and fabrication process are significantly simpler than previous types of tilt sensors. The dimensions of the prototype tilt sensor are $20mm{\times}20mm$, and the diameter of the polystyrene tube is 5 mm with a tube thickness of 0.15 mm. An analytical study of the prototype capacitive tilt sensor was undertaken, and the experimental results demonstrate the relationship between the tilt angles and measured capacitances compared with the analytical study.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.4
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• pp.440-443
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• 2010

This paper deals with the method of vibration measurement of a gun barrel structure using mechanical filter. When a bullet with high speed is moving within a gun barrel type structure with low bending vibration frequencies, it is difficult to measure the bending vibration signals of the structure. For example, noncontact type sensors such as displacement or velocity sensor are not appropriate for the measurement of vibrational signals because of the movement effect of the equipment frame through the moving structures or effect of the ground vibration. One of contact type sensors such as accelerometer is profitable for measurement of vibrational signals because of its wide measurement ranges. In the case of a gun barrel structure including high vibrational signals like shock waves, however, it is necessary to propose vibration measurement method filtering high frequencies. The purpose of the paper is to propose the proper vibrational measurement technique filtering high frequencies of a gun barrel type structure.

• Journal of the Korea Society of Computer and Information
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• v.16 no.5
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• pp.61-71
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• 2011

To measure the fatigue of metallic objects at high speed vibration while non-contact precision displacement measurement on how to have a lot of research conducted. Noncontact high-speed vibration detection sensor of the eddy current sensors and laser sensors are used, but it is very expensive. Recently, High-speed vibrations detection using an inexpensive inductive sensor to have been studied, but is still a beginner. In this paper, a new design of an inexpensive inductive proximity sensor has been suggested in order to measure high frequency dynamic displacements of metallic specimens in a noncontact manner. Detection of the existing inductive sensors, detection, integral, and amplified through a process to detect the displacement noise due to weak nature of analog circuits and integral factor in the process of displacement detection is slow. The proposed method could be less affected by noise, the analog receive and high-speed signal processing is a new way, because AD converter (Analog to Digital converter) without using the vibration frequency signals directly into digital signals are converted. In order to evaluate the sensing performance, The proposed sensor module using non-contact vibration signals were detected while shaker vibration frequencies from 30Hz to 1,100 Hz at intervals of vibrating metallic specimens. Experimental results, Vibration frequency detection range of the metallic specimins within close proximity to contactless 5mm could be measured from DC to 1,100Hz and vibration amplitude of the resolution was $20{\mu}m$. Therefore, the proposed non-contact inductive sensor module for precision vibration detection sensor is estimated to have sufficient performance.

• Smart Structures and Systems
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• v.15 no.3
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• pp.881-896
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• 2015

The authors' research group has developed a noncontact type of sensors which directly measure the inter-story drift displacements of a building during a seismic event. Soon after that event, such seismically-induced drift displacement data would provide structural engineers with useful information to judge how the stories have been damaged. This paper presents a scheme of estimating the story cumulative plastic deformation ratios based on such measured drift displacement information toward the building safety monitoring. The presented scheme requires the data of story drift displacements and the ground motion acceleration. The involved calculations are rather simple without any detailed information on structural elements required: the story hysteresis loops are first estimated and then the cumulative plastic deformation ratio of each story is evaluated from the estimated hysteresis. The effectiveness of the scheme is demonstrated by utilizing the data of full-scale building model experiment performed at E-defense and conducting numerical simulations.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.6
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• pp.513-519
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• 2016

In this study, dynamic vertical displacement of liquid in the tuned liquid column damper(TLCD) is measured by a laser Doppler vibrometer(LDV) to overcome limitations of existing sensors and to leverage noncontact sensing. Addressing advantages of noncontact measurements, operational principles of the LDV to measure velocity and displacement of a target object in motion is explained. The feasibility of application of the LDV to measurement of liquid motion in the TLCD is experimentally explored. A series of shake table tests with the TLCD are performed to determine requirements of application of the LDV. Based on the experimental results, it is proved that the LDV works under the condition of adding dye to the liquid by increasing the intensity of reflected laser and thus validity is verified by comparison with a conventional wave height meter.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.181-184
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• 2007

This paper deals with the method of vibration measurement of a gun barrel structure using mechanical filter. When a bullet with high speed is moving within a gun barrel type structure with low bending vibration frequencies, it is difficult to measure the bending vibration signals of the structure. For example, noncontact type sensors such as displacement or velocity sensor are not appropriate for the measurement of vibrational signals because of the movement effect of the equipment frame through the moving structures or effect of the ground vibration. One of contact type sensors such as accelerometer is profitable for measurement of vibrational signals because of its wide measurement ranges. In the case of a gun barrel structure including high vibrational signals like shock waves, however, it is necessary to propose vibration measurement method filtering high frequencies. The purpose of the paper is to propose the proper vibrational measurement technique filtering high frequencies of a gun barrel type structure.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.2 s.95
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• pp.23-30
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• 1999

This paper investigates the radial performance of self-acting spiral-grooved air bearing, used to support small high-speed rotating bodies. Repeatable runout, nonrepeatable runout, stiffness and supporting load are selected as the performance. The clearance between rotor and stator, the stator groove depth, and the rotating speed are chosen as three main parameters affecting the performances. Force application and displacement measurement are done in a noncontact manner, in order not to disturb operation: electromagnetic force is applied to the rotor and gap sensors are used to measure the displacement of the rotor. Experimental results show that repeatable runout decreases as speed, groove depth and clearance decrease. Nonrepeatable runout decreases as clearance decreases, and it has a minimum value at $5.5{\mu}m$ of grove depth and a maximum value at speed of 18.000rpm. Stiffness increases as speed increases and clearance decreases, and has a maximum value around $5.5{\mu}m$ of groove depth. The relationship between force and displacement is linear for small displacement, but becomes nonlinear for large displacement. Supporting load is linearly proportional to the stiffness, and it is a maximum value around $4.75{\mu}m$ of clearance.