• Journal of the Korean Society for Nondestructive Testing
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• v.37 no.1
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• pp.44-49
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• 2017

본고에서는 열유도 적외선 열화상 기법의 원리와 응용에 있어 기초적인 개념, 특정 상태량 및 실험적 기법에 대하여 소개하도록 한다. 유도 열화상 기법에 적용되는 유도 주파수의 범위는 1500 Hz ~ 52 MHz이며 강자성 강재 단조 부품의 표면결함 검출에 사용되어진다. 균열 검출 감도는 자분탐상기법과 유사하나 필요한 경우 유도 주파수를 낮춤으로서 강재에 숨겨진 결함을 검출할 수 있다. 탄소섬유강화폴리머(CFRP)에서는 섬유 결함을 검출하며, 실리콘 태양 전지에서는 양호한 열적 콘트라스트와 함께 균열을 검출한다. 유도 열화상 기법의 향 후 대표적인 활용분야로는 레일 및 휠과 같은 철도 구성요소에서의 결함 탐상이 있다[1].

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.10
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• pp.765-772
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• 2020

A lot of studies to overcome the limitation of flight time have been studied, since the requirement of complicated mission achievement of aircraft including Unmanned Aerial Vehicles(UAVs) has been increased. The fuel limitation could bring about not enough flight time to accomplish missions. For this reason, the rendezvous maneuver is required to accomplish aerial refueling missions. The rendezvous guidance law based on variable pursuit guidance is designed using Lyapunov stability theory in this study. Numerical simulation is performed to demonstrate the performance of the proposed rendezvous guidance.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.3
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• pp.282-287
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• 2015

In modern warfare, the importance of SEAD(Suppression of Enemy Air Defense) mission is being emphasized. However, this mission runs the risk of hull damage or casualties of our friendly air forces. Because of these risks, research on the way of minimizing damages and enhancing mission capability is under active discussion. As a part of this research, SEAD mission planning with multiple UAVs has been covered using vector field guidance. This guidance method not only applies to various forms of flight path but also requires less computational power than other guidance methods. Therefore, in this paper, planning methods of SEAD mission for multiple UAVs using vector field guidance and experimental data from flight experiments regarding designed mission has been covered.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.9
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• pp.839-847
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• 2011

This paper proposes a new guidance law for increasing the lethality of munitions. The well known PNG (Proportional Navigation Guidance) is inadequate for the munitions because of some weaknesses. Even if the munition does not have the impact point error, the acceleration command is non zero because the line-of-sight changes at all times in flight. Therefore, we use a difference between a target and an impact point. This proposed guidance law is similar to PNG in the form, but this guidance law concentrates a correction rate of flight path angle instead of the LOS (Line of Sight) rate. The correction of flight path angle is defined as the amount of impact point error. This impact point error can be calculated by neural networks rapidly. Finally, we show that the simulation results prove the suitability of this law.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.560-564
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• 2009

본 연구는 충적하천에 저수로를 유도하기 위한 기법으로 충적하천의 수충부에 수제를 설치하여 침식을 막고 대안측에 사주발생역의 발달을 억제하여 저수로를 유도하는 기법을 제시하였다. 수제는 하천의 흐름을 하도 중앙으로 집중시켜 주운을 위한 일정수심을 확보하는 역할을 하며, 흐름방향과 유속을 제어함으로써 흐름에 의한 제방침식작용을 방지하는 호안 역할을 병행한다. 최근 들어 자연생태계 복원에 대한 관심이 점차 증가함에 따라 하천정비사업에서도 자연친화적인 기법적용에 대한 관심 또한 커지고 있다. 이러한 관점에서 수제는 효과적인 자연친화 정비기법의 하나로 부각되고 있다. 따라서 본 연구에서는 2차원 수리해석 프로그램인 RMA2를 적용하여 만곡부에서 저수로를 합리적으로 유도하는 기법을 제시한다.

• Journal of Aerospace System Engineering
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• v.18 no.2
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• pp.1-11
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• 2024

This paper applies a relative impact angle control guidance law to a communication-based multi-missile network system with uncertainties and disturbances. The multi-missile network system is represented as a transitive reduction directed acyclic graph. Furthermore, this paper introduces both centralized and decentralized guidance laws based on the graph's structure. The relationship between these guidance laws is analyzed by comparing them based on the communication structure and the presence of system noise. To analyze the effects of decentralized optimal cooperative guidance law, this paper assumes uncertainty in missile dynamics and predicted impact point information for the relative impact angle control mission. Monte Carlo simulations are conducted for various mission environments to analyze the impact of communication and its structure on the system.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2490-2492
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• 1999

본 논문에서는 벡터 제어 유도전동기 구동 시스템에서 과변조시 출력 토오크 향상을 위한 새로운 과변조 기법을 제안한다. 제안된 과변조 기법은 인버터의 전압 제한과 유도 전동기의 전류 다이나믹스를 동시에 고려하여, 과변조시 동기좌표계 d축 전압을 감소시킴으로써 순시적으로 d축 전류를 감소시키고 q축 전류 제어를 위한 전압 여유를 확보한다. 따라서 과변조시에도 q축 전류 제어가 원활하게 수행됨에 따라 전동기의 출력 토오크를 향상시킨다. 기존의 기법과의 비교 실험에서 제안된 기법이 우수함을 증명하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.8
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• pp.631-638
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• 2018

In this paper, we propose a method to improve the performance by guidance technique and applying it to the precision guided ammunition. The proposed method is a technique designed to reduce the target error of ammunition by reducing the projectile error without analyzing the motion characteristics of the shot. This technique is applied to the moving average filter technique which is widely used as signal processing technique to reduce the fluctuation of the output of the inboard mounting inertial sensor caused by the rotation and the coning motion of the ammunition. In order to compare the performance of the applied technique including the simple 3D guided control technique and the proposed improvement technique. It is confirmed that the application of this technique improves the accuracy of impact of the cannon - launched ammunition with severe environmental conditions and irregular motion characteristics unlike the missile.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.308-309
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• 2016

This paper deals with ship's track keeping methods which is crucial part of automatic navigation control systems. In this paper, we mainly discuss the performance of different guidance methods including way point guidance, enclosure-based steering guidance and lookahead-based steering guidance system. As a controller, a PID control system is employed to control ship's rudder angle during track-keeping. Finally, the performance of three methods are discussed through some simulation results.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.84-85
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• 2013

본 논문은 스파스 매트릭스 컨버터로 구동되는 유도전동기에 과도응답특성 개선을 위한 모델예측제어 기법을 제안한다. 제안하는 기법은 유도전동기의 파라미터를 이용하여 구한 예측 토크와 자속을 통하여 비용함수를 최소화하는 최적의 스위칭 상태를 결정한다. 시뮬레이션을 통해 제안한 제어 기법의 타당성을 검증한다.