• Journal of Advanced Marine Engineering and Technology
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• 제32권2호
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• pp.241-249
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• 2008

In this study, lateral vibration analysis has been conducted on a propulsion and lift shafting system for an air cushion vehicle using ANSYS code. The shafting system is totally flexible multi-elements system including air propeller, aluminum alloy of lift fan and thin walled shaft with flexible coupling. The analysis included the lateral natural frequencies, mode shapes and harmonic analysis of the shafting system taking into account three-dimensional models for propulsion and lifting shaft system. In case of ACV the yawing and pitching rate of craft will be quite high. During yawing and pitching of craft significant gyroscopic moment will be applied to the shafting and will generate high amplitude of lateral vibration. So, such a shafting system has very intricate lateral vibrating characteristics and natural frequencies of shafting must be avoided in the range of operating revolution. The control of lateral vibration is included in this study.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.330-333
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• 2003

In this thesis. the application of the synchronizing control of the intelligent indoor lift system is showed. The separate axes of the indoor lift system are driven independently. PID controller, synchronous flexible logic compensating method and tilt sensor are applied to enhance the performance of the intelligent indoor lift system. the tilt sensor senses the horizontal error of the whole system. PID controller and synchronous flexible logic are used to compensate the synchronous errors of both the separate axes and whole system to be zero. Namely, using not the hardware coupling but the software algorithm. the indoor life system is operated without the error. Before applying the real system, the simulation using matlab testifies the possibility of the lift system. And the realization of the system is demonstrated with two DC servo motors. In the experiment test, flexible logic to compensate the synchronous error is chosen by the comparative method. the indoor lift system has to be considered the loading factor as the disturbance. Because the intelligent indoor lift system is developed to support the patients who don't change for themselves to move. finally, the system which considers the weight of the patient as the disturbance can carry the patients safely without synchronous and position error.

• Journal of Advanced Marine Engineering and Technology
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• 제31권4호
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• pp.335-342
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• 2007

A propulsion and lift shafting system in an air cushion vehicle is flexible multi-elements system which consists of two aeroderivative gas turbines with own bevel gears, four stage lift fan reduction gear, two stage propulsion reduction gear air propellers and high capacity of lifting fans. In addition, the system includes the multi-branched shafting with multi-gas turbine engines and thin walled shaft with flexible coupling. Such a branched shafting system has very intricate vibrating characteristics and especially, the thin walled shaft with flexible couplings can lower the torsional natural frequencies of shafting system to the extent that causes a resonance in the range of operating revolution. In this study, to evaluate vibrational characteristics some analytical methods for the propulsion and lift shafting system are studied. The analysis, including natural frequencies and mode shapes, for five operation cases of the system is conducted using ANSYS code with a equivalent mass-elastic model.

• 한국소음진동공학회논문집
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• 제24권1호
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• pp.14-20
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• 2014

Recent developments for high altitude, long endurance conventional UAVs(HALE UAVs) have revealed new issues regarding aircraft structure design and analysis. First of all, due to intensive mission requirements, the structures of HALE UAVs have lightweight and very flexible main wing with high aspect ratio, and slender fuselage. For this kind of structures, aeroelastic characteristics are different from conventional aircrafts. Hence, currently developed analysis methods are not suitable to fully understand strucutral dynamics of the very flexible aircraft, and to guarantee structural reliability. Therefore, various structural studies considering nonlinear behaviors which are generally ignored for the conventional aircraft strucutral analyis have been attracting researchers interests. Nonlinear flutter of the very flexible wing is one of the subject to be studied in combination with strong coupling between aeroelastic characteristics and flight dynamics. Herein, as preliminary study, modeling and nonlinear system analysis of the 2D airfoild with torsional nonlinearity have been discussed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 추계학술대회 논문집
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• pp.226-231
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• 2013

Recent developments for high altitude, long endurance conventional UAVs (HALE UAVs) have revealed new issues regarding aircraft structure design and analysis. First of all, due to intensive mission requirements, the structures of HALE UAVs have lightweight and very flexible main wing with high aspect ratio, and slender fuselage. For this kind of structures, aeroelastic characteristics are different from conventional aircrafts. Hence, currently developed analysis methods are not suitable to fully understand strucutral dynamics of the very flexible aircraft, and to guarantee structural reliability. Therefore, various structural studies considering nonlinear behaviors which are generally ignored for the conventional aircraft strucutral analyis have been attracting researchers interests. Nonlinear flutter of the very flexible wing is one of the subject to be studied in combination with strong coupling between aeroelastic characteristics and flight dynamics. Herein, as preliminary study, modeling and nonlinear system analysis of the 2D airfoild with torsional nonlinearity have been discussed.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.315-320
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• 1992

This paper presents the simulation architecture and strategy for dynamic simulation of chemical process and describes key features of developed dynamic simulation system, MOSA(Multi-Objective Simulation Architecture). A plant structure may be partioned into several strong coupling units, called cluster. If this cluster is solved simultaneously, it is possible to simulate whole plant without introducing convergence problem of tear streams. In this study, a flexible modular approach based on clusters was proposed as a promising architecture for dynamic chemical process simulator.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1997년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 1997
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• pp.132-132
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• 1997

The influence of the dam-reservoir interaction on the seismic response of concrete dam is studied. The dam body is assumed to behave elastically and modeled by FEM. The impounded water is assumed to be inviscid and compressible fluid and modeled by BEM. The seismic response of dam-reservoir system is analyzed by coupling two regions : the dam body and reservoir.

• 한국측량학회지
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• 제19권3호
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• pp.253-261
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• 2001

현재 하천의 수질관리를 위하여 여러 수질모델이 개발되어 있으며, 이러한 수질예측모델에 각종 수질관리에 따른 대안을 적용시킴으로써 그 효과를 사전에 모의 평가하고 있다. 그러나 이러한 수질모델을 적용하기 위해서는 복잡한 형식의 입력자료 구축단계가 요구되고 있으며 모델을 통한 타당한 분석결과를 산출하였음에도 불구하고 모델 자체의 표현의 한계성으로 인하여 효과적인 의사결정 자료로서의 활용이 미약한 실정이다. 본 연구는 GSIS를 이용한 하천수질모의에 관한 연구로서, 기존 수질모델의 이러한 제약을 극복하고자 GSIS환경에서 유역별 오염부하량을 산정하고 입력자료를 생성하며 모의결과를 시각화하는 인터페이스를 개발함에 있어 모델의 전ㆍ후처리과정에 GSIS를 적용하는 유연한 통합(Flexible coupling) 방법을 이용하여 수질모델과 GSIS를 통합하였다. 수질모델로는 기존의 하천수질모델 중 우리나라의 실정에 적합하여 비교적 정확하고 또한 그 적용이 간단하여 많은 지역에서 실제 적용되어 그 적용성이 검증된 QUAL2E 모델을 사용하였다.

• 한국실내디자인학회논문집
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• 제25권6호
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• pp.3-14
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• 2016

According to Plato's ontology, we lead our lives by establishing a relationship with others in the society. However in rapidly changing era, our lives was gradually moving towards personal tendency. Even for the relationship with family, not with others. Thus, awareness about owning properties has changed due to the sociocultural factors and increase number of single-person households. So in this study, the considerations for single-person housing were perceived through preceding research, and the elements making spatial boundary of shared housing were drawn to make rational space sharing based on the boundary with others and of the living environment. With overall analysis based on the spatial boundary features of planned shared housing, the plan characteristics according to the spatial boundary of the current shared housing is to be drawn and analyzed. Third, The expressive and structural features of spatial boundary as above appear with mutual flexible connectivity, And the result shows that the modularity was the highest. Among them variable coupling modularity of shows how it is possible to combine efficiently and variously the private and public spaces with regularity of 'space of optimal unit'. This study drew plan characteristics from more detailed space border of shared housing. Therefore, The basic framework of the characteristics spin for the cases that newly emerge later on.

• 한국항공우주학회지
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• 제31권2호
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• pp.63-71
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• 2003

본 논문에서는 유연우주비행체의 강인 선회기동을 위한 슬라이딩 모드 제어기법에 대해 연구하였다. 본 연구에서는 유연우주비행체의 1축 선회기동을 위한 선회목표각, 목표각속도 및 중앙동체와 유연부착물 사이에 작용하는 내부 반력 모멘트를 포함하는 슬라이딩 평면을 설계하였다. Lyapunov 제어기법과 비교한 결과 두 제어기법 모두 공칭 시스템에 대한 명령 추종성을 확인하였으며, 특히 슬라이딩 모드 제어기법의 적용결과 시스템 파라메터의 변동 및 외란의 영향에도 좋은 제어결과를 얻을 수 있음을 확인하였다. 1축 선회제어 결과를 확장하여 임의의 3축 선회기동을 수행할 수 있는 슬라이딩 모드 제어기를 설계하였다. 3축 선회기동 제어를 위해 쿼터니언을 이용하여 비행체의 자세를 결정하였고, 3개의 축 각각에 대해 설계된 슬라이딩 평면으로부터 선회기동시 발생하는 각 축간의 커플링 효과를 고려하여 제어기를 설계하였다. 설계된 제어기는 효과적인 3축 선회기동을 수행할 수 있음을 수치 시뮬레이션을 통해 보여주고 있다.