• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.5
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• pp.23-29
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• 2008

Magnetic abrasive polishing is one of the nontraditional machining technologies newly developed. But it was very difficult to cut non-magnetic materials using MAP process because the process was fundamentally possible by help of a magnetic farce. In this study, we aimed to verify analytically formation of the magnetic field in a case of the nonmagnetic materials especially focused on an aluminum alloy. And also an improving strategy of the magnetic force for the non-magnetic materials was proposed and experimentally verified. Design of experimental method was adopt for assessment of parameters' effect on the MAP results of the aluminum alloy.

• Proceedings of the KIEE Conference
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• summer
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• pp.815-817
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• 2004

This paper deals with the characteristics analysis and experiments of operating actuator for automatic door operated by fire detecting sensor. The dynamic characteristics of operating actuator system are analyzed on the structure of the operating actuator model. Simulation and experimental result have been performed for the verification of the proposed system and dynamic characteristics applied to a actuator by electromechanical energy conversion theory. The experimental result have been compared with proposed theoretical predictions. In this experimental result represented the temperature T1 and T2 which remarks T1 is a circumstance of operating actuator system, and T2 is a fire detecting sensor part.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.375-378
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• 2005

Voice Coil Motor is used linear motion actuator system that require precision positioning control. In order to control precision positioning of voice coil motor, Mathematical model of voice coil motor is needed. Mathematical model is obtained by combining voice coil motor's equation of motion with the equation of circuit and characteristic of voice coil motor. The induced model can predict output displacement according to duty ratio and amplitude. The model is verified by experimental test. Simulated results have tracking errors of less than 10 percent of experimental results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.883-888
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• 2004

One of commercial rapid transits produces peculiar booming sound when passing through the slab-track tunnel. In order to analyze that tympanic membrane-pressing noise systematically, typical source-transfer path-response analysis was carried out. Considering the octave band of booming noise, work scope was confined to structure-borne noise analysis, especially the dynamic behaviour of railway tracks. Experimental modal analysis of railway tracks, composed of rail, rubber pad, sleeper, ballast, and ground were performed. The results shows that transversal bending modes of the rail are suspicious for the cause of the low band booming noise. Finite element analysis are made use of to match preceding experimental results, and plausible dynamic properties of track components are produced.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.223-226
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• 2005

In previous research, we proposed robust saturation controller which involves both actuator's saturation and structured real parameter uncertainties. This controller can analytically prescribed the upper and lower bounds of parameter uncertainties, and guarantee the closed-loop robust stability of the system in the presence of actuator's saturation. And the availability and the effectiveness of the proposed robust saturation controller were verified through numerical simulations. In this paper, we verify the robust stability of this controller through experimental tests. Especially, we show unstable cases of other controllers in comparison with this controller. Experimental tests are carried out in the laboratory using a two-story test structure with a hydraulic-type active mass damper.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.534-539
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• 2000

A flexible rotating beam test bed has been developed for experimental verification of flexible rotating beam dynamics and vibration. It consists of a flexible arm, harmonic driver reducer, ac servo motor and DSP board with PC. To capture the motion induced stiffening effects of the flexible rotating beam, substructuring model has been established in multibody dynamics simulation. Substructuring model provides better results comparing with experimental data.

• Journal of Ocean Engineering and Technology
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• v.22 no.1
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• pp.70-74
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• 2008

It is important to reduce the vibration and noise of submarines and ships. For the purpose of noise reduction, various researches are actively being conducted on the employment of complex structures. However, in the case of numerical analysis for complex structures with damping materials, substantial errors can be generated by the absence of an exact damping model. Thus experimental model analysis is necessary for the verification of a numerical analysis for complex structures. In this research, vibration experiments are conducted in order to ascertain the vibration properties of cantilever beam attached damping materials. First, an initial value is obtained by using a direct linear method. Next, based on this initial value, the exact modal parameters of the cantilever beam are obtained by using the Newton-Raphson method.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.828-832
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• 1995

This paper describes the efficient design, analysis method and experimental verification of capacitor discharge impulse magnetizer system. A capacitor discharge magnetizer system is used to produce a high current impulse of short duration in this magnetizing fixture. The parasitic resistance and parasitic inductance of the capacitor discharge impulse magnetizer system have been estimated using known air-core test coil. Finite element analysis (using MAXWELL 2-D field simulator) and magnetizing circuit analysis (using SPICE) are also used as part of the design and analysis process of the capacitor discharge impulse magnetizer system. Application study for a magnetizing fixture design is shown. 8-pole magnetizing fixture has been designed and analyzed using finite element analysis. The fixture design for 8-pole magnet are presented along with the experimental results. The experimental results have been achieved using a high-voltage, high-energy capacitor discharge impulse magnetizer and 8-pole iron core fixtures (charging voltage : 2000[V], capacitor bank : 4000[$\mu\textrm{F}$]).

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.5
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• pp.197-217
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• 2022

As automated vehicle(AV) accidents continue to occur, the importance of safety verification to ensure the safety and reliability of automated driving system(ADS) is being emphasized. In order to encure safety and reliability, it is necessary to define an operational design domain(ODD) of the ADS and verify the safety of the ADS while evaluating its ability to respond in situations outside of the ODD. To this, international associations such as SAE, BSI, NHTSA, ISO, etc. stipulate ODD standards. However, in Korea, there is no standard for the ODD, so automated vehicles's ODD expression method and safety verification and evaluation are not properly conducted. Therefore, this study analyzed overseas ODD standards and selected suitable ODD for safety verification and evaluation, and presented evaluation elements for ADS safety verification and evaluation. In particular, evaluation elements were selected by analyzing the evaluation environment of the automated driving experimental city (K-City) that supports the development of ADS technology.

• Smart Structures and Systems
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• v.24 no.6
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• pp.769-781
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• 2019

Dynamic displacement response of civil structures is an important index for in-construction and in-service structural condition assessment. However, accurately measuring the displacement of large-scale civil structures such as high-rise buildings still remains as a challenging task. In order to cope with this problem, a vision-based system with the use of industrial digital camera and image processing has been developed for long-distance, remote, and real-time monitoring of dynamic displacement of supertall structures. Instead of acquiring image signals, the proposed system traces only the coordinates of the target points, therefore enabling real-time monitoring and display of displacement responses in a relatively high sampling rate. This study addresses the in-situ experimental verification of the developed vision-based system on the Canton Tower of 600 m high. To facilitate the verification, a GPS system is used to calibrate/verify the structural displacement responses measured by the vision-based system. Meanwhile, an accelerometer deployed in the vicinity of the target point also provides frequency-domain information for comparison. Special attention has been given on understanding the influence of the surrounding light on the monitoring results. For this purpose, the experimental tests are conducted in daytime and nighttime through placing the vision-based system outside the tower (in a brilliant environment) and inside the tower (in a dark environment), respectively. The results indicate that the displacement response time histories monitored by the vision-based system not only match well with those acquired by the GPS receiver, but also have higher fidelity and are less noise-corrupted. In addition, the low-order modal frequencies of the building identified with use of the data obtained from the vision-based system are all in good agreement with those obtained from the accelerometer, the GPS receiver and an elaborate finite element model. Especially, the vision-based system placed at the bottom of the enclosed elevator shaft offers better monitoring data compared with the system placed outside the tower. Based on a wavelet filtering technique, the displacement response time histories obtained by the vision-based system are easily decomposed into two parts: a quasi-static ingredient primarily resulting from temperature variation and a dynamic component mainly caused by fluctuating wind load.