• Journal of the Korean Society for Aviation and Aeronautics
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• v.24 no.3
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• pp.37-47
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• 2016

After a thorough investigation of aviation accidents involving Korean national carriers both inside and outside of Korea and also after reviewing catastrophic events involving foreign carriers in Korea, we found numerous accidents that caused fatalities and serious personal injuries. Although the aircrafts involved were found to have no specific defects, many of the accidents were caused by the pilot's misjudgement according to previous studies. Our research is to find an new procedure to help the prevention of similar accidents by focusing particularly on CFIT accidents during the procedural operations of Non Precision Approach, Circling Approach and Visual Approach. Therefore, we emphasize the significance of this research on the development of the new checklist that will help achieve a safe and effective procedural operation for non precision approaches.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.14 no.4
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• pp.110-119
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• 2006

This research was conducted with a view to enhance the efficiency of the preventive tool which provide pilots and controllers with proper and timely safety alerts while conducting circling approach at the airport where surrounding terrains becomes threat to safe operation of flight around airport.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.537-543
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• 1997

A new procedure for the advanced one-side measurement of longitudinal wave and surface wave velocities in concrete is presented in this paper. Stress waves are generated in a consistent fashion with a DC solenoid. Two piezoelectric accelerometers are mounted on the surface of a specimen as receivers. Stress waves propagate along the surface of the specimen and are detected by the receivers. In order to reduce the large incoherent noise levels of the signals, signals are collected and manipulated by a computer program for each velocity measurement. For a known distance between the two receivers and using the measured flight times, the velocities of the longitudinal wave and the surface wave are measured. The velocities of the longitudinal wave determined by this method are compared with those measured by conventional methods on concrete, PMMA and steel.

• Aerospace Engineering and Technology
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• v.7 no.1
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• pp.61-67
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• 2008

To design flight control law of an unmanned aerial vehicle, automated control gain determination program was developed. The procedure for determination of control gain was formulated as the control gains were designed from the optimal solutions of the optimization problem. PSO algorithm, which is one of the evolutionary computation method, and SQP algorithm, which is one of the nonlinear programming method, are used as optimization problem solver. Thru this technique, computation time required for finding the optimal solution is decreased to 1/5 of that of PSO algorithm and more accurate optimal solution is obtained.

• Journal of Advanced Engineering and Technology
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• v.11 no.4
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• pp.273-277
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• 2018

In the field of forest disaster prevention, drones are expected to save higher human resources than the existing manpower has, and produce high-efficiency results over time. However, operational limitations brought by short flight times have brought the environment of limited use of the various capabilities of the drone, and the existing development systems operating the multi-drone are mainly for performance purpose, so it is a difficult to use for forest disaster prevention. The purpose of this paper is to design the concept based on multi-drone operation procedure through analysis of mission of ground control system for forest disaster prevention.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.28 no.4
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• pp.55-62
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• 2020

Special airworthiness certificates can be issued if the aircraft does not meet the airworthiness standards, but it is deemed that it can be operated safely by partially limiting the scope of operation and flight performance. Currently, Korea is subject to experimental special certification for UAS(Unmanned Aircraft Systems) exceeding 150 kg of its own weight, but detailed guidelines need to be prepared on how to prove that they can be operated safely in a limited range. Recently, Korea Airworthiness Standard(KAS) Part 21 has been revised to reflect this, but it needs to be supplemented. In this study, through an understanding and analysis of the FAA's procedure of expeirmental special airworthiness certifications for UAS, we would like to suggest what we should consider when developing relevant guidelines in our country.

• The Journal of Korea Robotics Society
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• v.18 no.3
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• pp.316-322
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• 2023

The increasing popularity of autonomous unmanned aerial vehicles (UAVs) can be attributed to their wide range of applications. 3D path planning is one of the crucial components enabling autonomous flight. In this paper, we present a novel 3D path planning algorithm that generates and utilizes curvature-based trajectories. Our approach leverages circular properties, offering notable advantages. First, circular trajectories make collision detection easier. Second, the planning procedure is streamlined by eliminating the need for the spline process to generate dynamically feasible trajectories. To validate our proposed algorithm, we conducted simulations in Gazebo Simulator. Within the simulation, we placed various obstacles such as pillars, nets, trees, and walls. The results demonstrate the efficacy and potential of our proposed algorithm in facilitating efficient and reliable 3D path planning for UAVs.

• Advances in aircraft and spacecraft science
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• v.10 no.5
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• pp.473-494
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• 2023

This article introduces a formalism for the analysis of airplane trajectories on which the motion is determined by specifying the power of the engines. It explains a procedure to solve the equations of motion to obtain the value of the relevant flight parameters. It then enumerates the constraints that the dynamical abilities of the airplane impose on the amount of fuel used, the speed, the load factor, the lift coefficient, the positivity and upper boundedness of the power available. Examples of analysis are provided to illustrate the method proposed, with rectilinear and circular trajectories. Two very different types of airplanes are used in the examples: a Silver Fox-like small UAV and a common Cessna 182 Skylane.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.6
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• pp.503-508
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• 2007

In this study, the aeroelastic response and stability of bearingless rotors are investigated using a large deflection beam theory. The outboard main blade, flexbeam, and torque tube are all assumed to be an elastic beam undergoing arbitrary large displacements and rotations. The finite element equations of motion obtained from Hamilton's principle. Two-dimensional quasi-steady strip theory is used to evaluate aerodynamic forces. In hover, the modal approach method based on coupled rotating natural modes is used for the stability analysis. In forward flight, the nonlinear periodic blade steady response is obtained by integrating the full finite element equation in time through a coupled trim procedure with a vehicle trim. The results of the full finite element analysis using the large deflection beam theory are compared with those of a previously published modal analysis using the moderate deflection-type beam theory.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.2
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• pp.107-114
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• 2007

This paper focuses on the performance evaluation of various control allocation methods applied on DURUMI-II UAV system. In order to implement control allocation scheme to aircraft control system, control system can be designed through two step design procedure. The first step is to design a baseline control system for an aircraft without consideration of control surface failure. The second step is to design a control allocator that maps the total control command on the individual control surfaces. In this paper, several control allocation methods such as Psuedo-Inverse CA method, Direct CA method, and Optimization CA method are implemented and integrated to the baseline flight control system of DURUMI-II UAV. The performance of these control allocation methods is evaluated by nonlinear simulation under the flight scenario of control surface failure.