• 제어로봇시스템학회논문지
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• 제22권8호
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• pp.619-626
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• 2016

This paper proposes the design and performance evaluation of a marine engine fault detection system using a proximity sensor for marine engine. Non-linearity is greatly reduced by using the sensor without increasing the response time by applying the CANopen protocol. The CANopen protocol enables the sensor to send initial values and measurement data. The marine engine fault detection system measures crankshaft deflection and the bottom dead center of the crosshead in real-time, which maintains stability and prevents the serious breakdown of the marine engine by use of an interlocking alarm monitoring system.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 봄 학술발표회 논문집
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• pp.349-356
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• 1998

A method of calculating the natural frequency corresponding to the first mode of vibration of beams and tower structures, with irregular cross sections and with arbitrary boundary conditions was developed and reported by Kim, D. H. in 1974. In this paper, the result of application of this method to the three span continuous reinforced concrete bridge with elastic intermediate supports in presented. Such bridge represents either concrete or sandwich type three span bridge on polymeric supports for passive control or on actuators for active control. Any method may be used to obtain the deflection influence surfaces needed for this vibration analysis. Finite difference method is used for this purpose, In this paper. The influence of the modulus of the foundation and $D_{22}$, $D_{l2}$, $D_{66}$ stiffnesses on the natural frequency is thoroughly studied.d.

• International Journal of Aerospace System Engineering
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• 제2권2호
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• pp.44-49
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• 2015

A gust response analyses method based on Reduced Order Models (ROMs) was developed in the paper. Firstly, taken random signal as the input signal and adopt Single Input-Multi-Output (SIMO) training fashion, a ROM based on Auto-Regressive and Moving Average model (ARMA) was established and validated with the comparison of CFD/CSD and experiment. Then, by introducing control surface deflection and control laws, flutter active suppress was studied. Lastly, through filtering and transferring function, the gust temporal signal is obtained based on Dryden gust model, and gust response and suppress were simulated.

• KCI Concrete Journal
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• 제11권3호
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• pp.115-126
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• 1999

An analytical method based on the nonlinear layered finite element method is developed to simulate an overall load-deflection behavior of strengthened beams. The developed model distinguishes itself by its capability to trace residual flexural behavior of a beam after the fracture of brittle strengthening materials at peak load. The model. which uses a rather advanced numerical technique for iterative convergence to equilibrium, can be regarded as superior to the two models based on load control and displacement control The model predictions were compared with the experimental results and it was observed that there was good agreement between them.

• Composites Research
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• 제17권4호
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• pp.18-24
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• 2004

본 논문에서는 복합재 구조물에 대하여 형상기억합금 선을 이용한 능동 형상 제어에 관한 연구를 수행하였다. 형상기억합금 선의 열-기계적인 특성을 실험적으로 측정하였으며, 복합재 보 시편의 표면에 볼트를 이용하여 형상기억합금 작동기를 고정하는 방법으로 하이브리드 복합재 구조물을 제작하였다 형상기억합금 작동기는 온도 상승에 의한 상변화에 의해 작동되며, 본 연구에서는 형상기억합금 작동기에 전력을 가하여 내부 저항을 통해 발생하는 열을 이용하여 구동하였다. 보다 빠르고 정확한 형상 및 변형 제어를 위하여 수치적 시뮬레이션을 통한 PID 되먹임 제어기를 설계하였으며, 형상기억합금 작동기에 적용하는 실험을 수행하였다.

• 대한기계학회논문집A
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• 제35권11호
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• pp.1423-1428
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• 2011

본 논문은 비선형 구동기를 포함한 유연시스템의 잔류변위저감을 위한 학습입력성형제어기를 제시한다. 제시되는 제어기는 비선형 구동기에 대한 입력성형제어기, 반복최소자승법 및 설계변수 updating rule 을 통합하여 개발된다. 비선형 구동기에 대응한 입력성형제어기 설계변수의 updating mechanism 을 개선하기 위한 잔류변위 측정함수가 제시된다. 제시된 제어방법을 pendulum system 에 적용하여 변수추정의 수렴성과 변위저감제어성능의 평가를 통해 수치해석적으로 실용성이 검증된다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.21-29
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• 1994

This paper presents a method to accommodate failures that affect aircraft dynamical characteristics, especially control surface jams on a large transport aircraft. The approach is to use the slow effectors, such as the stabilators or engines, in the feedforward manner. The simulation results indicate the performance of the RFCS. In some cases of control surface jam, the aircraft cannot recover without using the stabilators. Although the inputs to the slow effectors are determined using the nominal parameters, the effects of parameter change can be compensated by adjusting the control parameters for the fast surfaces. In the case of rudder jam, if the remaining control surfaces and the differential thrust cancel the moments produced by the stuck rudder, using the engine control improves time responses and reduces deflection angles of the control surfaces. If not, however, the aircraft starts a large rolling motion following a yawing motion. In that case, the stabilators should be used to damp the induced rolliig motion, instead of trying to directly cancel the moments caused by the stuck rudder. Unfortunately, the proposed control law for the stabilators does not give such inputs, because it does not take into account the dynamical effects which stuck surfaces have on the aircraft motions. However, we have shown through simulation that the aircraft can be recovered by giving the stabilators the control inputs that counteract the induced rolling moment. Besides, the method has also been shown through simulation to be effective in maintaining control during a situation similar to an actual accident. Finally let us mention a problem with the RFCS. As stated above, we have not established a method to select a trim point which call be reached as easily as possible using the remaining control effectors. In fact, recovery performance considerably depends on the trim states. As pointed out in Ref. 11, finding the best trim point for impaired aircraft will be one of the most difficult questions in RFCS design.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3529-3533
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• 2007

The advantages of the SITVC(secondary injection thrust vector control) technique over mechanical thrust vector systems include a reduction in both the nozzle weight and complexity due to the elimination of the mechanical actuators that are used in conventional vectoring. Computational study is performed to understand the fluidic thrust vectoring control of an axisymmetric nozzle, in which secondary gas injection is made in the divergent section of the nozzle. The nozzle has a design mach number 3. The effect of injection hole number and shape of secondary jet on the mach number distribution of SITVC were investigated. The standard ${\kappa}$ - ${\epsilon}$ turbulence model solved the complex three-dimensional nozzle flows perturbed by the secondary gas jet. The numerical code was validated by experiment. The results showed that the mach number distribution of circular and square nozzle are similar each other. As number of second injection hole increasing, a effect of deflection was decreased.

• International Journal of Aeronautical and Space Sciences
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• 제13권3호
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• pp.361-368
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• 2012

This paper presents an approach on the design of a nonlinear controller to track a reference velocity for an air-breathing supersonic vehicle. The nonlinear control scheme involves an adaptation of propulsive and aerodynamic characteristics in the equations of motion. In this paper, the coefficients of given thrust and drag functions are estimated and they are used to approximate the equations of motion under varying flight conditions. The form of the function of propulsive thrust is extracted from a thrust database which is given by preliminary engine input/output performance analysis. The aerodynamic drag is approximated as a function of angle of attack and fin deflection. The nonlinear controller, designed by using the approximated nonlinear control model equations, provides engine fuel supply command to follow the desired velocity varying with time. On the other hand, the stabilization of altitude, separated from the velocity control scheme, is done by a classical altitude hold autopilot design. Finally, several simulations are performed in order to demonstrate the relevance of the controller design regarding the vehicle.

• 제어로봇시스템학회논문지
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• 제6권8호
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• pp.682-688
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• 2000

To improve the performance of a flexible robot arm one of the important things is the vibration displacement measurement of a flexible arm. Many types of sensors have been used to measure it, The most popular has been strain gauges which measures the deflection of the beam,. Photo sensors have also been for detecting beam displacement and accelerometers are often used to measure the beam vibration. But the vibration displacement can be obtained indirectly from these sensors. In this article a vision sensor is used as a displacement sensor to measure the vibration displacement of a flexible robot arm. Several schemes are proposed to reduce the image processing time and increase its accuracy. From the experimental results it is seen that the vision sensor can be an alternative sensor for measuring the vibration displacement and has a potential for on-line tip position control of flexible robot systems.