• 대한기계학회논문집
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• 제18권6호
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• pp.1399-1411
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• 1994

A model helicopter has more versatile flight capability than the fixed-wing aircraft and it can be used as an unmaned vehicle in hazardous area. A helicopter, similar to other aircrafts, is an unstable, multi-input multi-output nonlinear system exposed to strong disturbance. So it should be controlled by robust control theories that can be applied to multivariable systems. In this study, motion equations of hovering are established, linearized and transformed into a state equation form. Various parameters are measured and calculated in other to obtain the stability derivatives in the state equation. Hovering flight controller is designed using the digital LQG/LTR(Linear Quadratic Gaussian/Loop Transfer Recovery) control theory. The designed controller is tested by the nonlinear simulations and implemented on an IBM-PC/386. Experiments were carried out on a model helicopter attached to the 3-DOF gimbal. The designed controller showed satisfactory hovering capability to maintain the hovering for more than 40 seconds.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2006년도 추계 학술대회논문집
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• pp.151-154
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• 2006

In the present paper, hovering performance analyses of proprotor and helicopter rotor blades were performed by using FLUENT software. As a proprotor, TRAM(Tilt Rotor Aeroacoustic Model) was selected and performance analysis was carried out with mesh adaptation for more elaborate solution. As a helicopter rotor blades, two bladed Caradonna and Tung's rotor and four-bladed BO-105 helicopter rotor blades were selected. In case of Caradonna and Tung's rotor, vortex trajectory was compared with experimental data to inspect the vortex convection capability of the present flow solver. For the final case, performance of BO-105 helicopter rotor blades was investigated and compared with experimental data. After performance analyses of proprotor and helicopter rotors, it was shown that the present solver showed reasonable vortex strength, wake geometry and thurst coefficient distributions. But power coefficient was somewhat overestimated about $10%{\sim}15%$ regard less of mesh adaptation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.92-92
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• 2000

Helicopter offer the signigicant advantage over traditional air vehicles, in that the provide extended maneuverability, such as vertical climb, hovering, longitudinal and lateral flight, hovering turns and bank turns. But helicopter have the strong cross couplings and nonlinearities for each lateral, longitudinal and rotational motion mutually. However, it is possible to ignore this couplings for the hovering condition, so using this properties we can control the attitude of helicopter. That is, by implementing the dynamic of each rotational axis(roll, pitch, yaw) of independent mutually, 3-DOF(degree of Freedom) attitude control for the helicopter is possible. In this paper, we identify decoupled input-coutput relations of each three rotational axis about the helicopter mounted on the 3-DOF gimbal by experiment, and on these basis implement 3-DOF attitude controller using the PID control method.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 춘계학술대회 논문집
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• pp.340-346
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• 2013

This paper describes a helicopter vibration induced by main rotor in forward flight. The hub loads in the fixed frame, which are dominant source of helicopter vibration, are obtained by multi-blade summation of rotating blades loadings. The components of 3/rev, 4/rev, and 5/rev blades loadings are transmitted by blades to 4/rev hub loads in the fixed frame. The vertical vibrations of helicopter at pilot seat and copilot seat are calculated through rigid body transfer functions considering airframe to be rigid body. The blades are assumed to be elastic and undergo the flap, lag, and torsion motion and free wake aerodynamic model is used to calculate the precise blade loadings in the analysis. The 4/rev vertical vibration responses are analyzed from rotating blade loadings and fixed hub loadings.

• 한국항공운항학회지
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• 제15권3호
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• pp.15-23
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• 2007

In this paper, we deducted the missions with respect to Korea utility helicopter (KUH) and consist of the scenarios which describe proper purpose of KUH. And so developed fatigue load spectrum of KUH by applying Helix that is fatigue load spectrum for blade of articulated helicopter rotor system. The developed load spectrum is applied to fatigue analysis of blade by modeled finite element with stress-life method (S-N). And we compared the result of fatigue analysis to prior to Helix for the sake of verifying the load spectrum that we generated.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.325-329
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• 2003

Nowadays many peoples are using helicopter in various fields, not only military use but also common people applications such as air-measurement, photography, transportation of goods and persons, saving life and fire fighting etc. And it will be expected more popular than now. Most important part of helicopter to increasing performance and to reducing noise is rotor hub-system. Hub system consists of rotor-blade and rotor-hub. We participate to develop next-generation rotor hub system with elastomeric bearing, part of rotor hub. In this paper we introduce about the role and shape of elastomeric bearing in next-generation helicopter hub system. Then we study about bearing-material requirements and measuring methods. Finally we represent some experimental results.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.210-214
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• 1998

Radio-Controlled helicopter has superior movement abilities like as hovering or backward move. So it has been used as a sprinkler of agricultural medicines or an observer of dangerous area such as a volcano, etc. But its operation is not simple because it has many control factors and they interfere with each other. Therefore the helicopter is not controlled by simple theory in the case of automatic operation. Then fuzzy sliding mode control, which has fastness, fineness and robustness, is thought to be suitable to satisfy various requirements of the helicopter operation. In this work, the fuzzy sliding mode control was applied to the flying of RC helicopter, As tile result, it was controlled with good performance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2283-2285
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• 2001

This paper proposed to a neural network based fuzzy control (neuro-fuzzy control) technique for attitude control of helicopter with strongly dynamic nonlinearities and derived a helicopter aerodynamic torque equation of helicopter and the force balance equation. A neuro-fuzzy system is a feedforward network that employs a back-propagation algorithm for learning purpose. A neuro-fuzzy system is used to identify nonlinear dynamic systems. Hence, this paper presents methods for the design of a neural network(NN) based fuzzy controller(that is, neuro-fuzzy control) for a helicopter of nonlinear MIMO systems. The proposed neuro-fuzzy control determined to a input-output membership function in fuzzy control and neural networks constructed to improve through learning of input-output membership functions determined in fuzzy control.

• 항공우주시스템공학회지
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• 제14권6호
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• pp.10-17
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• 2020

The Korean medical evacuation helicopter was developed based on the Korean Utility Helicopter (hereafter referred to as 'Surion'). It uses an auxiliary power unit and engine for heating during winter operation. The helicopter maintains the internal temperature of the aircraft using its bleed air to satisfy its operational capability. However, due to the air inflow through the gap between the aircraft skin and door, additional heating for operating the portable medical equipment and preventing hypothermia in evacuated patients is required. Accordingly, an electric auxiliary heater was developed for additional heating during winter operation, and environmental, durability, and performance tests were conducted per MIL-STD-810G and MIL-STD-461F. The auxiliary heater was verified per the tailored airworthiness certification criteria.

• 한국항공운항학회지
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• 제28권4호
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• pp.21-31
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• 2020

There are two to three helicopter accidents every year in Korea, representing 5.7 deaths per 100,000 flights. In this study, an analysis was conducted on helicopter accidents that occurred in Korea from 2005 to 2017. The accident analysis was based on the aircraft accident and incident report published by the Aircraft and Railway Accident Investigation Board. This Research analyzed the characteristics of accidents occurring in Korea caused by human error by pilots. Accident analysis was done by classifying the organization, flight mission, aircraft class, flight stage, accident cause, etc. Pilot's huan error was classified as Skill-based error, decision error and perceptual error in accordance with the HFACS taxonomy. The accidents caused by pilot's human error were classified into five categories: powerlines collision, loss of control, fuel exhaustion, unstable approach to reservoir, and elimination of tail rotor.