• Journal of Aerospace System Engineering
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• v.18 no.1
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• pp.29-36
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• 2024

Recently, the concept of Urban Air Mobility (UAM) has expanded to Advanced Air Mobility (AAM). A tilt rotor type of vertical take-off and landing aircraft has been actively studied and developed. A tilt-rotor aircraft can perform a transition flight between vertical and horizontal flights. A blade pitch angle control system can be used for flight stability during transition flight time. In addition, Individual Blade Control (IBC) can reduce noise and vibration generated in transition flight. This paper proposed Disturbance Observer Based Control (DOBC) and Time Delay Control (TDC) for individual blade control of an Electro-Mechanical Actuator (EMA) based blade pitch angle control system. To compare and analyze proposed controllers, numerical simulations were conducted with DOBC and TDC.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.335-336
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• 2009

• Electrical & Electronic Materials
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• v.10 no.8
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• pp.836-842
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• 1997

• Journal of Advanced Navigation Technology
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• v.20 no.5
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• pp.401-407
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• 2016

This paper introduces 3-dimensional path planning and guidance including power model for high altitude long endurance (HALE) UAV using solar energy. Dubins curve used in this paper has advantage of being directly available to apply path planning. However, most of the path planning problems using Dubins curve are defined in a two-dimensional plan. So, we used 3-dimensional Dubins path generation algorithm which was studied by Randal W. Beard. The aircraft model which used in this paper does not have an aileron. So we designed lateral controller by using a rudder. And then, we were conducted path tracking simulations by using a nonlinear path tracking algorithm. We generate examples according to altitude conditions. From the path tracking simulation results, we confirm that the path tracking is well on the flight path. Finally, we were modeling the power system of HALE UAVs and conducting path tracking simulation during 48hours. Modeling the amount of power generated by the solar cell through the calculation of the solar energy yield. And, we show the 48hours path tracking simulation results.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.3
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• pp.311-320
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• 2008

A LIDAR can rapidly generate 3D points by densely sampling the surfaces of targets using laser pulses, which has been efficiently utilized to reconstruct 3D models of the targets automatically. Due to this advantage, LIDARs are increasingly applied to the fields of Defense and Security, for examples, being employed to intelligently guided missiles and manned/unmanned reconnaissance planes. For the prior verification of the LIDAR applicability, this study aims at generating simulated LIDAR data. Here, we derived the sensor equation by modelling the geometric relationships between the LIDAR sub-modules, such as GPS, IMU, LS and the systematic errors associated with them. Based on this equation, we developed a program to generate simulated data with the system parameters, the systematic errors, the flight trajectories and attitudes, and the reference terrain model given. This program had been applied to generating simulated LIDAR data for urban areas. By analyzing these simulated data, we verified the accuracy and usefulness of the simulation. The simulator developed in this study will provide economically various test data required for the development of application algorithms and contribute to the optimal establishment of the flight and system parameters.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.06a
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• pp.265-268
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• 2008

Lidar(Light Detection and Hanging, Ladar)는 물체에 반사되어 되돌아오는 광학신호를 관측하여 물체와의 거리를 측정하는 센서로 정밀한 3차원 모델 생성 및 도시지역의 변화탐지 등에 효율적으로 적용될 수 있다. 시뮬레이션은 시스템의 동작을 인공적으로 만들어 내고, 이 동작의 실행을 관찰하여 실제 시스템의 특성을 추론하는 일련의 활동으로, 하드웨어의 설계 및 분석, 보완, 성능 평가 등에 효율적으로 이용된다. 본 연구에서는 Lidar 시스템의 원리 및 구조 분석을 통해서 Lidar 데이터를 시뮬레이션하기 위한 소프트웨어를 설계하였다. Lidar의 특성이 시뮬레이션 소프트웨어에 정확하게 구현되도록 하기위해 Lidar 동작과 관련된 내부 및 외부요소를 분석하고 기능에 따라 추상화하여 소프트웨어 모들로 구성하였다. 시스템 내부요소로 송신부 수신부 신호/영상처리부 모델과 외부환경요소로 비행환경 모델, 타겟 모델, 대기 모델을 정의하였다. 또한, Lidar 시스템 실행 중에 발생하는 주요 프로세스를 함수 모듈로 정의함으로서, 모델들 간의 구조적인 관계를 정의하였다. 본 연구의 설계결과는 이후 Lidar시뮬레이션 소프트웨어의 보다 체계적인 구현에 적용될 예정이다.

• Journal of IKEEE
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• v.19 no.4
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• pp.557-565
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• 2015

In this paper, a method for estimating the location of a quadcopter is proposed by applying an EKF-SLAM algorithm to its flight control, to autonomously control the flight of an unmanned quadcopter. The usefulness of this method is validated through simulations. For autonomously flying the unmanned quadcopter, an algorithm is required to estimate its accurate location, and various approaches exist for this. Among them, SLAM, which has seldom been applied to the quadcopter flight control, was applied in this study to simulate a system that estimates flight trajectories of the quadcopter.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.8
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• pp.807-815
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• 2008

In this paper, design, development and evaluation of DIP(Database Interface Program) are presented. The main purpose of this study is to improve the simulation quality to get more realistic response of target system. The designed and developed major function is composed of flexible memory structure, efficient arithmetic database language and high speed interpolation/extrapolation algorithm. To evaluate the operation speed and accuracy of returned data, trim simulation is performed based on in-house software and, DIP is applied to existing real-time simulator such as engineering HQS(Handling Quality Simulator) to evaluate reliability and performance. The result of evlaution reveals that calculation speed and data accuracy are satisfied, and flight performance is satisfied in the real-time simulator environments.

• Journal of Advanced Navigation Technology
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• v.19 no.5
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• pp.379-388
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• 2015

In the end of 1990's, future free flight technology had been developed and tested in America and government established the plan for free flight until 2017. Aircraft separation assurance must be secured essentially to avoid collision between aircrafts before Free Flight comes true. Now, Civil aircraft has rules about avoidance activity with traffic collision avoidance system (TCAS) but it can't apply to light aircraft. So there is a need about alternative method to apply light-aircraft because it has space and price problem to use TCAS. In this paper, TCAS algorithm has been modified and verified by simulating with LABVIEW program under ADS-B condition to get miniaturization and weight lighting cheaply. By simulating, collision alert algorithm is analyzed and verified with collision situation proposed by ICAO, and 100% checked for performing the alert announciation on all cases by TCAS standards.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.11
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• pp.982-989
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• 2013

Omni-directional antennas of UHF-Band are located on the top and bottom side of the Smart UAV in order to connect a link always. Therefore one of each antennas should be connected to a ground antenna. Because the communication link of the omni-directional antennas is influenced by the objectives around aircraft, the clearance of LOS(Line of Sight) should be achieved in order to avoid a loss of link. In this paper, the analysis results on the influence of the complex objectives placed around the antenna on the communication link are presented according to the change of attitude angles. The best positions of antennas are selected based on the electromagnetic analysis using XGTD tool which supports the modeling of antenna pattern. The flight tests of the Smart UAV were successfully performed with the selected antenna position.