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A Study on the Development of the Position Detection System of Small Vessels for Collision Avoidance
Dang-Khanh Le,Teak-Kun Nam 해양환경안전학회 2014 海洋環境安全學會誌 Vol.20 No.2
본 연구에서는 단거리 영역 내에서 대상물표의 정확한 위치를 파악하여 물표와의 충돌을 방지하기 위한 시스템을 개발하였다. 이를 위해 먼저 물표를 속도 모델과 가속도 모델로 표현하여 초기위치로부터의 움직임을 프로세스 잡음과 측정 잡음이 있는 상태에서 위치, 속도 및 가속도를 추정하였다. 추정기법으로는 칼만필터를 적용하였고 시뮬레이션을 통해 제안기법의 유용성을 확인하였다. 다음으로는 레이저센서를 적용하여 이동하는 물표와의 거리를 계측할 수 있는 시스템을 제작하여 물표의 이동 정보를 검출하였다. 이동 물표를 대상으로 속도 모델과 가속도 모델을 적용하여 실험을 수행하였고, 각각의 실험을 통해 불연속적인 측정데이터가 필터링을 통해 매끄럽고 연속적인 측정값으로 얻어지는 것을 확인하였다. 또한 물표 데이터의 계측과 디스플레이를 위한 UI를 구축하였으며, 물표가 일정거리 영역이내에 접근했을 경우 시각, 청각적인 경보를 울릴 수 있는 기능을 부가하였다. 본 연구결과를 통해 저가의 장비로 물표 위치의 추정 성능이 뛰어난 시스템을 구축할 수 있었다. In this paper, a developed device for detecting target’s location and avoiding collision is proposed. Velocity and acceleration model of target are derived to estimate target's information, i.e. position, velocity and acceleration considering process and measurement noise. Kalman filtering method applied to the estimation process and its results was confirmed by simulation. The distance measurements system using laser sensor for moving target system is also developed to confirm the effectiveness of the proposed scheme. Experiments to get information of moving target with velocity and acceleration model was executed. The data with filtering and without filtering was compared by experiments. Discontinuous measured data was changed to smooth and continuous data by Kalman filtering. It is confirmed that desired data was obtained by applying proposed scheme.. UI for measuring and monitoring the target data is developed and visual and auditory alarm function is attached on the system Finally, position estimation system of moving target with good performance is achieved by low price equipments.
Principal Component Analysis for Heart Rate Measurement using UWB Radar
Le Dang Khanh,Pham Xuan Duong 한국지능시스템학회 2020 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.20 No.3
This paper proposes a signal processing approach based on principal component analysis (PCA) for monitoring heart rate using an ultra-wideband impulse (UWB) radar. Vital signals including respiration and heart rate is measured by a UWB radar, and then compressed and projected on the main principal component. This projection helps to significantly improve the signal-to-noise ratio in comparison to other conventional methods such as direct fast Fourier transform and complex signal decomposition. Thus, an accurate measurement of heart rate can be obtained. The proposed approach can help improve about 10 dB of heartbeat signal.
Dang-Khanh Le,Jin-Man Kim,Taek-Kun Nam 한국항해항만학회 2012 한국항해항만학회 학술대회논문집 Vol.2012 No.추계
본 연구에서는 레저선박 및 소형선박을 위한 지능형 충돌방지 시스템에 대한 언급하고 있다. 이 시스템의 기능은 선박으로부터 이동 물체까지의 거리와 속도를 추정하고 해당 물체와의 충돌을 회피하기 위한 제어신호를 발생하는 것이다. 본 논문에서는 칼만필터를 이용하여 대상물체의 위치와 속도를 추정하는 방법에 대해 소개한다. 실제 실험단계에서는 레이저센서를 이용하여 대상물체의 거리를 계측하고 계측된 신호에 필터링을 적용하여 대상물의 위치와 속도를 검출하게 된다. 제안한 기법의 유용성을 검증하기 위해 물체의 위치 및 속도추정에 대한 시뮬레이션을 수행하였다. In this research intelligent protection system for laser boat is introduced. The function of system is to measure the distance and velocity of object from our boat and generate control signals to avoid collision with moving targets. A novel approach to estimate object’s position from our ship is tackled on this paper. To do this laser sensors are used to measure distance from ship to targets. The ship position and velocity is estimated by th Kalman filter algorithm. In the real phase, the filtering method will be applied to process signal gathered by laser sensors. Simulation to estimate ship’s position and velocity under noise are executed and the results are introduced to show the effectiveness of the algorithm.
A study on the modeling of a hexacopter
Le, Dang-Khanh,Nam, Taek-Kun The Korean Society of Marine Engineering 2015 한국마린엔지니어링학회지 Vol.39 No.10
The purpose of this paper is to present the basic mathematical modeling of a hexacopter, which could be used to develop proper methods for stabilization and trajectory control. A hexacopter consists of six rotors with three pairs of counter-rotating fixed-pitch blades. This mechanism is an under-actuated, dynamically unstable, six-degrees-of-freedom system. The whole motion of this object consists of translational and rotational motion in three dimensions, where the translational motion is created by changing the direction and magnitude of the upward propeller thrust. The hexacopter is controlled by adjusting the angular velocities of the rotors, which are spun by electric motors. It is assumed to be a rigid body; thus, the differential equation of the hexacopter dynamics can be derived from the Newton-Euler equation. The Euler-angle parametrization of the three-dimensional rotations contains singular points in the coordinate space that can cause failure of both the dynamical model and control. In order to avoid singularities, the rotations of the hexacopter are parametrized in terms of quaternions. This choice has been made considering the linearity of the quaternion formulation and their stability and efficiency. Further, control simulation of a hexacopter applying cascaded-PID control is also presented in this paper.
A Study On The Controller Design Of Vibration Isolator
레당카잉(Dang-Khanh Le),남택근(Taek-Kun Nam),노영오(Young-Oh Roh) 한국마린엔지니어링학회 2010 한국마린엔지니어링학회 학술대회 논문집 Vol.2010 No.4
In this study the controller design for vibration isolator is discussed. The vibration isolator is developed to eliminate an influence of vibration generated from engines and other rotating machinery in the small boats. The vibration isolator developed is composed of plate, connecting rod and crank mechanism driven by electrical motor. A relation between control force and torque generated from motor is analyzed and pole-placement control method is applied to derive an adequate force. Some analysis result is introduced to verify the effectiveness of control procedure.