• 한국항공운항학회지
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• 제31권2호
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• pp.46-54
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• 2023

Helicopter pilots are required to perform many visual workloads in topographical avoidance, flight path modification and navigation, because helicopters operate at very low altitudes. The helicopter-specific instability also require the pilot to have precise perception and control. This has caused frequent human error in helicopter accidents. In Korea, two to three cases have occurred annually on average over the past 10 years, and this trend has not decreased. The purpose of this study was to identify human error risks in advance to prevent helicopter accidents and to help develop measures for missions and mission phases with high risk of human error. Through the study, the tasks and mission phases where accidents occur frequently were classified and the risk of human error was calculated for each mission phases. To this end, the task of frequent accidents during helicopter missions was first identified, detailed steps were classified, and the number of accidents was analyzed. Next, the AHP survey program was developed to measure the pilot's risk of human error and the survey was conducted on the pilots. Finally, the risk of human error by helicopter mission and by mission phases calculated and compared with the actual number of accidents.

• 한국항공운항학회지
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• 제15권4호
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• pp.33-37
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• 2007

In this paper, a dynamic analysis of a helicopter landing gear with considering flexible structural modes has been investigated. The main body of the helicopter has been modeled as a flexible body using FEM code, then a few selected vibration modes of the helicopter main body have been used as basis for the dynamic analysis of the helicopter landing gear. The simulation of dynamic analysis was carried out on the base of ADAMS aircraft module. It has been found by a series of simulation that the flexible structural modes has a significant effect on the dynamic characteristics of helicopter landing gear as the flexibility of the main body is increased.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.590-593
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• 2005

Unmanned Helicopter has several abilities such as vertical Take off, hovering, low speed flight at low altitude. Such vehicles are becoming popular in actual applications such as search and rescue, aerial reconnaissance and surveillance. These vehicles also used under risky environments without threatening the life of a pilot. Since a small unmanned helicopter is very sensitive to environmental conditions, it is generally known that the flight control is very difficult problems. The nonlinear adaptive fuzzy controller design procedure and its applications for altitude control of unmanned helicopter were described in the paper. This research was concentrated on describing the design methodologies of altitude controller design for small unmanned helicopter acquiring autonomous take off and vertical movement. The design methodologies and performance of the altitude controller were simulated and verified with an adaptive fuzzy controller. Throughout simulation results, I showed that the proposed adaptive controllers have enhanced control performance such as robustness, effectiveness and safety, in the altitude control of the unmanned helicopter.

• 한국정밀공학회지
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• 제28권8호
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• pp.951-958
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• 2011

In this paper, the purpose is to investigate the vibration characteristics and the design of resonance avoidance of the unmanned helicopter master. Based on the Euler-Bernoulli beam theory for helicopter master, the equation of motion is derived by using extended Hamilton's principle. It was studied about the natural frequency of helicopter master as the design variances(tip mass, length and diameter of master). Also, it was compared the theoretical results for natural frequency with the results of FE analysis. The results of this study showed the vibration characteristics of helicopter master for the design of resonance avoidance.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1992년도 춘계학술대회 논문집
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• pp.173-177
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• 1992

The Helicopter has a lot of flight modes. The most characteristic flight mode is Hovering. It enables the helicopter to be used in many situations. However, a helicopter has nonlinear dynamics so its mathematical modeling is very difficult. Hence it is not easy to control helicopter in hover. In this paper, RC model helicopter is selected as a plant. To stabilize the behavior of RC model helicopter, Fuzzy alogrithm is used as a controller and one camera is used as a sensor. To get proper Information from camera Image, three characteristic points are attatched to the helicopter and a position recognition algorithm is developed. Experiments are performed to stabilize 3 rotational motions synchronousely with fuzzy control algorithm. As a result, Fuzzy control represents better performances than the conventional PID control.

• 한국항공운항학회지
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• 제28권1호
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• pp.122-129
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• 2020

Korea's HEMS are mainly operated during the week, but they are pushing for 24-hour operations. This study has made an overall comparison and review of helicopter safety management that should be accompanied to this end. For research purposes, helicopter regulations and helicopter accident statistics were analyzed, with a high accident rate associated with pilot error and night flight. It was proposed that future preparations would require reinforcement of laws and regulations, reinforcement of pilots' night training, and introduction of training and preflight risk assessments. This study will provide a direction for future helicopter safety. This study will provide for future direction of helicopter safety research.

• 한국항공운항학회지
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• 제12권2호
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• pp.59-70
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• 2004

Most of studies on aircraft accidents have been conducted mainly for fixed-wing aircraft, while the studies on helicopter accidents have been done less even though the helicopter accidents occurred quite more than those of the fixed-wing. There are lots of differences between helicopter and fixed-wing accidents, in aspect of causes and occurrence of accidents as well as aerodynamics and operation. In Korea, helicopter accidents have occurred 2 or 3 times annually since 2000, while the number of fixed-wing aircraft accidents has been reduced considerably. The goal of this study is to solve the present safety problems in helicopter accidents by reviewing the characteristics of past accidents and comparing differences between two types of aircraft.

• 한국군사과학기술학회지
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• 제13권6호
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• pp.1099-1105
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• 2010

The purpose of this paper is to propose a methodology that can estimate optimal requirement of attack helicopter Korea army will be operating in future. For estimating optimal requirement, attack helicopter's operation concept, performance, battlefield environment and enemy threat are considered. We use a wargame model, AAsim(Army Aviation simulation), as a analytic simulation model which is used to analyze DOTMLPF and operation in army aviation field. In this paper, we conduct battle experiment for anti armored corps operation which reflects attack helicopter's combat effectiveness very well. As a result of simulation, the destructive rate for enemy armored corps per each attack helicopter can be calculated. In this paper, we propose optimal requirement of attack helicopter using that destructive rate for enemy armored corps.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1504-1508
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• 1996

In this paper, we derive dynamic equation of helicopter and design controller based on variable structure system. It is difficult to control helicopter because it has non-linear coupling between input and output of system and is MIMO system. The design of control law is considered here using variable structure methodology giving the robustness to parameter variations and invariance to some subsets of external disturbance. However we derive dynamic equations of helicopter and design stabilizing variable structure controller. Also, simulation results are given in this paper.

• 한국국방경영분석학회지
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• 제23권1호
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• pp.25-46
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• 1997

In this paper, we consider a tow-person zero-sum game in which an attack helicopter with a missile wishes to destroy a tank. The tank has much small-caliber ammunition for protection itself from the attack helicopter. And the attack helicopter possesses a missile for attacking the tank. We develop models for the behavior of the attack helicopter, in terms of missile launch time, and of the tank, in terms of ammunition firing rate, in several situations. In particular, we examine the Weiss-Gillman model.