• Structural Engineering and Mechanics
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• 제3권2호
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• pp.135-144
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• 1995

Since structural systems may fail in any one of several failure modes, computation of system reliability is always difficult. A method using numerical quadrature for computing structural system reliability with either one or more than one failure mode is presented in this paper. Statistically correlated safety margin equations are transformed into a group of uncorrelated variables and the joint density function of these uncorrelated variables can be generated by using the Maximum Entropy Method. Structural system reliability is then obtained by integrating the joint density function with the transformed safety domain enclosed within a set of linear equations. The Gaussian numerical integration method is introduced in order to improve computational accuracy. This method can be used to evaluate structural system reliability for Gaussian or non-Gaussian variables with either linear or nonlinear safety boundaries. It is also valid for implicit safety margins such as computer programs. Both the theory and the examples show that this method is simple in concept and easy to implement.

• 한국항행학회논문지
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• 제20권4호
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• pp.329-335
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• 2016

무인 항공 시스템 (UAS)은 무인 항공기 운용에 필요한 장비, 네트워크 및 운용 인원을 포함하는 시스템을 통칭한다. 이러한 무인 항공 시스템은 과거 군사적인 목적으로 주로 이용되었으나, 최근 기술 발전에 힘입어 점차 민간용 시장으로 확대되고 있으며, 국가 공역내 통합되어 시장 규모가 급격히 성장할 것으로 예상된다. 따라서, 공역내 안정적인 통합을 위해 표준화된 무인기 제어 및 비임무용 (CNPC; control and non-payload communication) 통신시스템의 구축 필요성이 증대되고 있으며, 미국, 유럽을 비롯한 선진국에서는 높은 신뢰성을 제공 가능한 제어용 통신 기술 개발을 진행하고 있다. 본 논문에서는 무인 항공 시스템의 CNPC 데이터링크의 기술개발 동향을 기술하고, IEEE 802.15.4 ZigBee 시스템을 개량한 CNPC 시스템의 성능 분석 결과를 제시한다.

• 한국항공우주학회지
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• 제32권6호
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• pp.23-33
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• 2004

다분야 통합 최적화 설계 환경을 제공하는 소프트웨어 체계인 MDO 프레임워크 개발을 위해서는 다양한 운영체계와 언어에서 개발된 해석코드들의 통합, CAD 및 데이터베이스 시스템과의 통합, 복잡한 GUI 환경의 구현 등이 필수적으로 요구되고 해석코드의 추가, 새로운 MDO 기법의 도입에 따른 수정 및 확장에 대한 고려가 충분히 이루어져야 한다. 본 논문에서는 MDO 프레임워크의 설계단계부터 고려되어야 할 사항들과 각 구성요소들의 시스템 통합 방법을 연구, 적용 방안을 제시하며 이를 바탕으로 비행체 통합 최적설계 시스템 환경을 구현하였다. MDF 및 CO 기법 등 대표적인 MDO 기법을 적용할 수 있는 데이터베이스 설계과정을 정립하고, 구현된 통합 최적설계 시스템을 이용하여 전투기 날개 형상 최적 설계를 수행하여 개발된 MDO 프레임워크의 효율성 및 유용성을 검증하였다. 구배 기반 최적화 기법을 이용하여 삼십번의 설계 반복으로 최적 날개 형상을 도출하였다.

• International Journal of Aeronautical and Space Sciences
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• 제17권4호
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• pp.604-613
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• 2016

In this paper, Human-in-the-Loop (HiTL) simulations of Remotely Piloted Aircraft System (RPAS) operations in two different Air Traffic Management (ATM) concepts, conventional radar vectoring and Trajectory Based Operations (TBO), were performed to assess the impacts of RPAS integration in the future ATM environment. TBO concept maximizes the throughput by planning and sharing 4-D trajectories between pilots and controllers, and it is considered one of the key concepts to enable RPASs to operate with manned aircraft in congested airspaces. RPASs are characterized by having communication delay or temporary loss of communication. TBO capability was added to the integrated air traffic simulation system for this study, which was developed in the Inha University. HiTL simulations were performed by a trainee air traffic controller with three scenarios, and the data were analyzed using safety, efficiency, and controller workload metrics. The results suggest that TBO were effective in reducing delays and controller workload while maintaining the level of safety.

• 한국인공지능학회지
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• 제12권2호
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• pp.17-23
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• 2024

Various methods have been developed to predict the flight path of an air-launched weapon to intercept a fast-moving target in the air. However, it is also getting more challenging to predict the optimal firing zone and provide it to a pilot in real-time during engagements for advanced weapons having new complicated guidance and thrust control. In this study, a method is proposed to develop an optimized weapon engagement zone by the SCG (Scaled Conjugate Gradient) algorithm to achieve both accurate and fast estimates and provide an optimized launch display to a pilot during combat engagement. SCG algorithm is fully automated, includes no critical user-dependent parameters, and avoids an exhaustive search used repeatedly to determine the appropriate stage and size of machine learning. Compared with real data, this study showed that the development of a machine learning-based weapon aiming algorithm can provide proper output for optimum weapon launch zones that can be used for operational fighters. This study also established a process to develop one of the critical aircraft-weapon integration software, which can be commonly used for aircraft integration of air-launched weapons.

• 제어로봇시스템학회논문지
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• 제11권7호
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• pp.633-643
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• 2005

An unmanned aerial vehicle (UAV) is an aircraft controlled by .emote commands from ground station and/o. pre-programmed onboard autopilot system. A navigation system in the UAV provides a navigation data for a flight control computer(FCC). The FCC requires accurate and reliable position, velocity and attitude information for guidance and control. This paper proposes an ADGPS/INS integrated navigation system for a UAV. The proposed navigation system comprises an attitude determination GPS (ADGPS) receive., a navigation computer unit, and a low-cost commercial MEMS inertial measurement unit(IMU). The navigation algorithm contains a fault detection and isolation (FDI) function fur integrity. In order to evaluate the performance of the proposed navigation system, two flight tests were preformed using a small aircraft. The first flight test was carried out to confirm fundamental operation of the proposed navigation system and to check the effectiveness of the FDI algorithm. In the second flight test, the navigation performance and the benefit of the GPS attitude information were checked in a high dynamic environment. The flight test results show that the proposed ADGPS/INS integrated navigation system gives a reliable performance even when anomalous GPS data is provided and better navigation performance than a conventional GPS/INS integration unit.

• 한국항행학회논문지
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• 제19권6호
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• pp.492-498
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• 2015

무인항공기시스템 수요의 증가와 기술의 급격한 발전에 따라 많은 국가들에서 기존의 공역 시스템에 무인항공기를 통합하려는 시도가 이루어지고 있다. 유인항공기와 무인항공기의 통합 운용에 따른 영향을 파악하기 위해서는 유무인항공기의 통합 시뮬레이션 시스템을 통한 HiTL (Human-in-The-Loop) 시뮬레이션이 필요하다. 본 논문에서는 유무인항공기 통합 시뮬레이션을 위한 운용 개념을 정의하고, 유무인항공기 통합 운용 시 발생 가능한 상황을 시나리오로 설정하여, HiTL 시뮬레이션을 수행하였다. 수행 결과에 대해 통신, 안전, 성능, HMI로 나누어 영향을 분석하였다.

• 한국항공우주학회지
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• 제44권9호
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• pp.825-832
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• 2016

본 논문에서는 항공전자시스템 통합시험에 사용하기 위한 데이터 버스 분석 장비 개발에 대해 기술하였다. 본 데이터 버스 분석 장비는 다양한 인터페이스를 수용할 수 있도록 대부분의 항공전자시스템에 채택되고 있는 MIL-STD-1553B, CAN(Controller Area Network), Ethernet 인터페이스 카드를 갖추었다. 버스 데이터의 수집과 분석을 동시에 효율적으로 수행하기 위해 수집 엔진과 분석 엔진은 각각의 하드웨어를 가진다. 데이터 분석 효율성을 높이기 위해 Grid, 2D 및 3D 형태의 데이터 전시 기능을 제공한다. 데이터 버스 분석 장비의 검증은 시험 절차서에 입각하여 모듈 단위 테스트 및 모듈 간 통합 테스트를 수행하였다. 실제 시험 환경인 비행체 SIL(System Integration Laboratory) 환경에서 수행된 통합시험 결과를 통해 연동 요구도 검증 및 개발된 장비의 유용성을 확인하였다.

• 산업경영시스템학회지
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• 제43권1호
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• pp.143-150
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• 2020

To enhance the effectiveness of the FMS (flexible manufacturing system), it is necessary for the manufacturing control system to be upgraded by integrating the cyber and the physical manufacturing systems. Using the CPPS (Cyber-Physical Production System) concept, this study proposes a 4-stage vertical integration and control framework for an aircraft parts manufacturing plant. In the proposed framework, the process controller prepares the operations schedule for processing work orders generated from the APS (advanced planning & scheduling) system. The scheduled operations and the related control commands are assigned to equipments by the dispatcher of the line controller. The line monitor is responsible for monitoring the overall status of the FMS including work orders and equipments. Finally the process monitor uses the simulation model to check the performance of the production plan using real time plant status data. The W-FMCS (Wing rib-Flexible Manufacturing Control & Simulation) are developed to implement the proposed 4-stage CPPS based FMS control architecture. The effectiveness of the proposed control architecture is examined by the real plant's operational data such as utilization and throughput. The performance improvement examined shows the usefulness of the framework in managing the smart factory's operation by providing a practical approach to integrate cyber and physical production systems.

• 한국군사과학기술학회지
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• 제14권2호
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• pp.213-221
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• 2011

Avionics system tends to be designed to have the integrated architecture, and it is getting difficult and complex to verify the flight-critical function because of sophisticated structure. In Korean Utility Helicopter, mission computer acts as the MUX Bus Controller to handle the data from both communication, identification, mission/display and survivability equipment inside Mission Equipment Package and aircraft subsystems such as fuel system and electrical system while it is interfacing with Automatic Flight Control System and Full-Authority Digital Engine Control via ARINC-429 bus. The Flight Displays which is classified as flight-critical function in aircraft is implemented on Primary Flight Display after mission computer processes data from AFCS in order to generate graphics. This paper defines the flight-critical function implemented in mission computer for KUH, and presents the static and dynamic test procedures which is performed on System Integration Laboratory along with Playback Recorder prior to flight test.