• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.3
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• pp.229-236
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• 2014

In this paper, the guidance laws and controllers for the gliding guided artillery munition is studied. The gliding guided artillery munition has wings for gliding to increase a range; therefore previous guidance laws and controllers for the guided munition could not be applied. Concepts of vector field guidance and proportional navigation guidance are applied for mid-term and terminal guidance, respectively. The gliding guided artillery munition is operated within wide altitude and speed areas; therefore, the controllers are designed for each area, and gain-scheduling and the linear interpolation technique is applied to compute the appropriate gains.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.5
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• pp.364-370
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• 2019

In this paper, an individual blade control (IBC) methodology is applied to find the best input scenario for vibratory hub loads reduction of XH-59A co-axial rotorcraft in high speed flight. A comprehensive aeromechanics analysis code CAMRAD II is employed to analyze the aircraft. A parametric study is conducted for optimum IBC inputs leading to the maximum vibration reduction. Numerical results demonstrate that up to 50% reduction in the hub vibration index is obtained for an IBC input at 3/rev frequency with the amplitude and phase angle of 0.5 deg. and 300 deg., respectively. The upper rotor exhibits as much as 6% more vibration reduction as compared to that of the lower rotor due to a clean inflow characteristic of the rotor. It is found that further vibration reduction gain is reached for IBC inputs with advancing-side only control. The hub vibration becomes reduced by up to 17% in reference to that with full rotor disk control. It is noted that the additional gain is obtained with significantly less power input with the advancing-side only control.

• Journal of the Korea Convergence Society
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• v.8 no.4
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• pp.9-18
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• 2017

UAVs began to be actively applied to so-called 3D jobs, including the autonomous exploration, investigation, mapping, search and rescue, etc. since the mid-2000s. With this global trend, having a precise controllability of the UAV will certainly revolutionize the life of the modern human in the aspect of tremendous applications of the UAV. In the first part, a simplified dynamic model of the UAV identified using system identification techniques is compared with the previously built time-discrete linear model. In the second part, the three parameters of the dynamic model are estimated using the batch and RLS methods. Angular acceleration data of the quadrotor UAV at the hovering maneuver are analyzed and shown to be converging at all time. Also, according to the quadrotor flight data from both experiments and MATLAB simulations, the batch estimation method turns out to be more accurate than the RLS estimation method based on the comparison of final parameter values.

• Proceedings of the KIEE Conference
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• 1998.11b
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• pp.457-459
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• 1998

This paper presents a 3-DOF hovering flight controller for a model helicopter using the minimal order LQG/LTR technique. A model helicopter is an unstable multi-input multi-output nonlinear system strongly exposed to disturbances, so a robust multi-variable control theory should be applied to control it. The minimal order LQG/LTR technique which uses a reduced-order observer in the LTR procedure is used to design the controller. Performances for the 3-DOF hovering flight controller are evaluated through computer simulations.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.7
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• pp.1014-1018
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• 2012

This paper presents a decentralized controller design for formation flying of multiple satellites based on the overlapping decomposition technique. Each satellite is assumed to avail only the information of its own and in front of itself, which restricts the structure of a controller gain matrix to an overlapped form. The concerned large-scale system is expanded using the overlapping decomposition technique. Design condition is represented in terms of linear matrix inequalities with small-scale systems in a decentralized form, based on the expanded system. The resulting controller is contracted to the original overlapped form so as to close the original system. A numerical simulation shows the effectiveness of the proposed technique.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.729-732
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• 2014

본 논문에서는 실시간 영상에서 움직임 검출 및 추적에 관련한 기본 기술들을 나열하고 구현하여 구현 가능성 및 성능에 대하여 검증을 진행하였다. 움직임 검출에는 배경 차영상 기법에 의한 움직임 및 변화 영역 검출 방법과 움직임 히스토리에 의한 움직임 검출법, 광류에 의한 움직임 검출법이 있으며 이를 구현하여 검증하였다. 또한 움직임 추적의 경우에는 추적하려는 물체의 히스토그램의 역투영을 이용하면서 물체의 중심점을 추적하는 MeanShift와 물체의 중심, 크기, 방향을 함께 추적하는 CamShift가 있고 Kalman 필터에 의한 움직임 추적을 구현하여 검증하였다. 구현된 방법을 통하여 보안용의 영상감시 장비의 추적 시스템 및 GPS 좌표를 기반으로하여 비행체를 추적하면서 통신링크를 유지하는 추적안테나 시스템에 적용하므로서 제어의 정확도를 높일 수 있다.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.6
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• pp.26-34
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• 2007

The efforts to develop high performance aircraft engines are successively progressed with development of recent technology. The reliability of individual parts and the safety of engine systems are reduced if high efficiency components, high strength materials, and precise controls are applied to the engine with complexity to increase engine performance. In this paper, the regulation requirements and assessment technique for aircraft engine safety are considered, and the result of safety assessment on a turbine case cooling system of high efficiency turbofan engine is presented.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.9
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• pp.916-924
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• 2008

In this paper dynamic modeling parameters were estimated using a frequency domain estimation method. A systematic flight test method was employed using preprogrammed multistep excitation of the swashplate control input. In addition when one axis is excited, the autopilot is engaged in the other axis, thereby obtaining high-quality flight data. A dynamic model was derived for a small scale unmanned helicopter (CNUHELI-020, developed by Chungnam National University) equipped with a Bell-Hiller stabilizer bar. Six degree of freedom equations of motion were derived using the total forces and moments acting on the small scale helicopter. The dynamics of the main rotor is simplified by the first order tip-path plane, and the aerodynamic effects of fuselage, tail rotor, engine, and horizontal/vertical stabilizer were considered. Trim analysis and linearized model were used as a basic model for the parameter estimation. Doublet and multistep inputs are used to excite dynamic motions of the helicopter. The system and input matrices were estimated in the frequency domain using the equation error method in order to match the data of flight test with those of the dynamic modeling. The dynamic modeling and the flight test show similar time responses, which validates the consequence of analytic modeling and the procedures of parameter estimation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.2
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• pp.182-188
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• 2018

In order to increase the robustness of the uplink for UAS(Unmanned Aerial System), we propose a jamming signal rejection algorithm. In the UAS datalink system, DSSS (direct sequence spread spectrum) is used to reduce the radio noise or jamming signal. In general, jamming signals below the spreading gain are recoverable but the signals beyond the spreading gain can not be recovered. In this paper, these jamming signals beyond spreading gain are detected using the threshold detector in the spectrum area then, generate the estimated signals from the sine wave generator. Finally, we obtain the desired signal to remove jamming signals from the received signals. The proposed scheme can eliminate jamming signals while minimizing the hardware complexity and the original signal loss.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.9
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• pp.114-129
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• 1996

This paper describes the whole development phase for the underwater vehicle actuating system with high hydroload torque disturbance. This includes requirement analysis, system modeling, control algorithm design, real time implementation, test and performance evaluations. As for driving control algorithms, fuzzy logic, variable structure and PD(Proportional-Differential) algorithm were designed and implemented on board controller using a single chip microprocessor. Intel 8797. And test and performance evaluation is carried out both single test and wystem integration test. We could confirm the basic performance of actuating system through the single test and gereral developing work of any actuating systems was finished with a single performance test of actuating system without system integration test. But, we suggested that system integration test be needed. System integration test is carried out using G/C HILS(Guidance and Control Hardware-In-the -Loop Simulation) which is constituted flight motion simulator, load simulator, real time host computer and the related subsystems such as inertial navigation system, power supply system and Guidance and Control Computer etc.. The most important practical contribution of this paper is that full system characteristics such as minimal control effort, enhancement of guidance and autopilot performance by the actuating system using G/C HILS technique are investigated. Through full running G/C HILS, in spite of the passing to single tests, some control algorithm resulted in failure as to stability of full system and system time frame.