• Journal of Advanced Navigation Technology
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• v.18 no.3
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• pp.215-222
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• 2014

In this paper, parafoil airdrop system has been designed and analyzed. 6-degrees of freedom (6-DOF) model of the parafoil system is set up. Nonlinear model predictive control (NMPC) and Proportion integration differentiation (PID) methods were separately applied to adjust the flap yaw angle. Compared the results of setting time and overshoot time of yaw angle, it is found that the of yaw angle is more stable by using PID method. Then, trajectory following controller was designed based on the simulation results of trajectory following effects, which was carried out by using MATLAB. The lateral offset error of parafoil trajectory can be eliminated by its lateral deviation control. The later offset deviation reference was obtained by the interpolation of the current planning path. Moreover, using the designed trajectory, the trajectory following system was simulated by adding the wind disturbances. It is found that the simulation result is highly agreed with the designed trajectory, which means that wind disturbances have been eliminated with the change of yaw angle controlled by PID method.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.1
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• pp.102-108
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• 2016

A flying drone generates vibrations in a great variety of frequencies, and it requires a gimbal system stabilization loop design in order to obtain clean and accurate image from the camera attached to the drone under this environment. The gimbal system for drone comprises the structure that supports the camera module and the stabilization loop which follows the precise angle while blocking the vibration from outside. This study developed a dynamic model for one axis for the stabilization loop design of a gimbal system for drones and applied classical PID controller and intelligent PID controller. The Stabilization loop design was developed by using MATLAB/Simulink and compared the performance of each controller through simulation. Especially, the intelligent PID controller can be designed almost without the dynamic model and it demonstrates that the angle can be followed without readjusting the parameters of the controller even when the characteristics of the model changes.

• Journal of Aerospace System Engineering
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• v.15 no.5
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• pp.72-80
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• 2021

Albatross uses dynamic soaring technique to obtain energy from horizontal winds and fly long distances without flapping. These dynamic soaring technique can be applied to manned/unmanned aircraft to reduce the components required for the aircraft and achieve light weight and small volume to effectively perform a given task. In this paper, to simulate the dynamic soaring technique of Albatross, we defined the optimization problem and set each boundary condition to derive the optimal flight trajectory and carry out simulations to follow it. In particular, to model dynamic soaring simulations more closely with reality, we proposed a horizontal wind model that changes every moment. This identifies and analyzes the effect of the time-variable horizontal wind model on the dynamic soaring mission of unmanned aircraft.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.22 no.4
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• pp.75-80
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• 2014

A lunar lander demonstrator developed for the purpose of demonstrating lunar landing technologies recently in Korea. The thruster control system of the lunar lander demonstrator adopted the main thrusters for altitude control and the reaction thrusters for attitude control. In this paper, we propose a path tracking controller base on Euler angles. The control signals of the controller are of continuous type. And Pulse Width Modulator(PWM) is adopted to provide On/Off signals. We perform MATLAB simulation for evaluating the path tracking performance and the final landing velocity of the lunar lander demonstrator.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.411-412
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• 2008

본 논문에서는 차세대원자로인 APR1400(Advanced Power Reactor 1400)의 출력제어방법으로 모델예측제어 알고리즘을 적용하고, 일일부하추종 운전을 하였을 때 최적의 제어기 구현을 위해 제어 로직의 주요 변수인 예측구간, 제어구간, 모델 차수의 변화에 따른 제어 성능을 평가하였다. 성능 평가는 원자로 출력제어 성능 검증시 사용하는 방법으로 제어대상인 차세대 원자로(APR1400)를 3차원 노심해석 전산코드인 MASTER(Multipurpose Analyzer for Static and Transient Effects of Reactor)로 시뮬레이션하여 제어 성능을 평가하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.3
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• pp.228-235
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• 2010

This paper deals with an autonomous flight controller design problem for a tilt-rotor aircraft in rotary-wing mode. The inner-loop algorithm is designed using the output-based approximate feedback linearization. The model error originated from the feedback linearization is cancelled within allowable tolerance by using single-hidden-layer neural network. According to Lyapunov direct stability theory, the adaptive update law is derived to run the neural network on-line, which is based on the linear observer dynamics. Moreover, the outer-loop algorithm is designed to track the trajectory generated from way-point guidance. Especially, heading and flight-path angle line-of-sight guidance are applied to the outer-loop to improve accuracy of the landing tracking performance. The 6-DOF nonlinear simulation shows that the overall performance of the flight control algorithm is satisfactory even though the collective input response shows instantaneous actuator saturation for a short time due to the lack of the neural network and the saturation protection logic in that loop.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1292-1293
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• 2015

기존에는 전동기 제어기법으로 PI제어기가 주로 사용되어 왔다. 그러나 실제 시스템의 경우 외란과 센서 잡음에 노출되기 쉽고, 모델의 불확실성에 대한 오차가 발생하기 때문에 보다 강인한 제어기법이 필요한 시점이다. $H{\infty}$제어기법은 명령 추종 성능, 시스템 모델 오차와 외란, 센서 잡음에 대해 강인성을 보장하는 고급제어기법으로서 현재 그 성능을 입증 받아 산업분야에서 다양하게 적용되고 있다. 본 논문은 매입형 영구자석 동기전동기(IPMSM)의 속도제어기에 $H{\infty}$제어기와 PI제어기를 적용하여 모의실험을 통한 성능비교를 통해 모델오차와 같은 시스템의 불확실성과 외란에 대해 $H{\infty}$제어기의 강인한 제어성능을 검증하였다.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.4
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• pp.11-19
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• 2008

The problem of controlling asynchronous sequential machines is addressed in this paper Corrective control means to make behavior of an asynchronous sequential machine equal to that of a given model. The main objective is to develope a corrective controller, especially when a model is given as nondeterministic, or a set of reference models. We first review representation of nondeterministic models and model matching problems with nondeterministic models, which are presented in the companion paper. We then propose necessary and sufficient conditions for the existence of corrective controllers and describe their design procedure. To show the applicability, the proposed control scheme is demonstrated in an example.

• Journal of Navigation and Port Research
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• v.35 no.3
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• pp.227-233
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• 2011

This paper presents the tracking and stabilization problem of a night vision system for marine surveillance. Both a hardware system and software modules are developed to control azimuth and elevation axes independently with compensation for ship motion. A two degree of freedom(2DOF) PID controller is designed and its parameters are tuned using a real-coded genetic algorithm(RCGA). Simulation demonstrates the effectiveness of the proposed method.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.5
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• pp.867-872
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• 2022

The effect of load is an important factor in precise speed control of a motor. n this study, we design a state observer that can estimate and define one state of disturbance including errors and nonlinear terms of mathematical models, which is not easy with a mathematical model. Then, the observation gain is set so that the estimation error of the state observation converges to 0, and the estimated state is used in the back stepping controller to design a controller capable of precise speed tracking. As a result of applying to 1 [hw] class Interior Permanent Magnet Synchronous Motor, excellent stste variable observation and tracking performance can be confirmed.