• Journal of Institute of Control, Robotics and Systems
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• v.9 no.2
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• pp.107-116
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• 2003

This paper presents a systematic design methodology for fault tolerant controller against a fault in actuators and sensors of linear stochastic systems with uncertainties. The scheme is based on fault detection and diagnosis(isolation and estimation) using a bank of robust two-stage Kalman filters, and accommodation of the actuator fault by eigenstructure assignment and immediate compensation of the sensor's faulty measurement. In order to clarify the fault feature in test statistics of residual, noise reduction method is given by multi-scale discrete wavelet transform. The effectiveness of our approach Is shown via simulations for a VTOL(vertical take-off and landing) aircraft subjected to parameter variations, external disturbances, process and sensor noises.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.19 no.1
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• pp.1-6
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• 2011

The free-wing tilt-body aircraft is researched in the flight performance characteristics such as short take-off and landing capability, and reduced sensitivity to gust and center of gravity (CG) change. Due to the main wing separating from the fuselage, the high tiltable empennage, and the stub-wing strongly influencing from the propeller wake, the resulting vehicle aerodynamics and flight dynamics are quite different from those of a conventional fixed-wing aircraft. Using the governing flight dynamics model was studied previously, all of speed and body tilt angle is simulated to determine the flight envelope by a non-linear 3-DOF flight simulation analysis. Though flight performance and trimmability are studied, the flight model of free-wing tilt-body aircraft is to reduce the hidden risk and to achieve the successful flight test. It is analyzed the flight characteristics that distinguishes free-wing tilt-body aircraft from the conventional aircraft.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.2
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• pp.101-107
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• 2007

A coaxial rotor flying robot is developed for surveying and reconnoitering various circumstances under calamity environment. The robot has two contrarotating rotors on a common axis, an embedded microcontroller, an IMU(Inertial Measurement Unit), an IR sensor for height control, a micro camera for surveillance, ultrasonic position sensors and wireless communication devices. A bell-bar mounted on the top of the upper rotor hub increases stability and improves flight performance. In this paper, we present a dynamic model of a coaxial rotor flying robot and design an embedded controller far the robot, and implement them to control the developed flying robot. Experimental results show that the proposed controller is valid for autonomous hovering and position control.

• International Journal of Aeronautical and Space Sciences
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• v.9 no.2
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• pp.58-63
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• 2008

This paper describes aerodynamic performance enhancement of cycloidal rotor according to the blade pivot point movement and the blade preset angle adjustment. Cycloidal blade system which consists of several blades rotating about an axis in parallel direction and changing its pitch angle periodically, is a propulsion mechanism of a new concept vertical take off and landing aircraft, cyclocopter. Based on the designed geometry of cyclocopter, numerical analysis was carried out by a general purpose commercial CFD program, STAR-CD. According to tills analysis, the efficiency of cycloidal rotor could be improved more than 15% by the introduced methods.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.6 s.99
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• pp.718-723
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• 2005

The purpose of this study is to present a fundamental data for evaluating aircraft noise of building site development. By the field experiments and the predicted equal noise level contours using the INM program, actual condition in the building site development arranged district was investigated. In order to get the results, Analysis of factors effected on noise level, sound level on the rate of increase to aircraft demand and difference on the aircraft noise levels according to floor level in apartment house was carried out. As a result the influence of the take-off and landing direction were appeared greatly. The influences of the height at receiving point, movement number of aircraft and increase to aircraft demand were appeared small And the influence of 1 day average WECPNL must be considered.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.3
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• pp.193-199
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• 2005

VTOL(Vertical Take-Off and Landing) aircraft is attractive due to the reason that it is not necessary to have long runway. However a rotorcraft has a definite limitation to fly at the high speed due to the stall at the tip of rotor. To solve this problem, tilt rotor, tilt wing and lift fan were researched and developed. It was verified that the tilt rotor aircraft among them was more effective in disk loading. On this basis, the tilt rotor aircraft has been made into XV-15, V-22, BA-609 and Eagle Eye. This paper shows a nonlinear simulation program for general tilt rotor aircraft that was developed in order to validate the flight characteristics of tilt rotor aircraft and verified through the simulation analysis.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.521-523
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• 2004

The Japan Aerospace Exploration Agency (JAXA) has proposed new vertical take-off and landing (VTOL) aircraft known as the Jet-VTOL aircraft shown in Fig.1. The Jet-VTOL aircraft is based on a canard wing configuration. The aircraft has the clustered lift-fans mounted near the center of gravity for vertical flight, and has the clustered fans mounted beside the vertical tail for cruise flight. Both fans are driven by the core engine mounted inside the aft end of fuselage. The propulsion system is innovative and attractive not to be seen even in the world.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1116-1118
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• 1996

This paper designs a digital controller by making use of the $H^{\infty}$ control algorithm and $\mu$-synthesis in order to keep a balance of the VTOL(Vertical Take Off and Landing Plane) vehicle with 4 fans. A identification of the actual model is acquired by the vehicle rolling, pitching and yawing angles for a pseude-random signal input and various identification theories. In spite of parameter variations and existing disturbances, the designed controller showes its robust performance through simulations and experiments.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.12
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• pp.1260-1265
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• 2008

This study deals with modeling and flight control of quadrotor type (QRT) unmanned aerial vehicles (UAVs). Rigorous dynamic model of a QRT UAV is obtained both in reference and body frame coordinate systems. A disturbance observer (DOB) based controller using the derived dynamic models is also proposed for robust hovering control. The control input induced by DOB is helpful to use simple equations of motion satisfying accurate derived dynamics. The experimental results show the performance of the proposed control algorithm.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.14-16
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• 2010

A Duct surrounding a fan is known to reduce the tip loss and increase the fan performance efficiency. It also reduces the fan noise drastically. Ducted fan, therefore, has been focused to be a promising candidate for high efficient propulsion system. In this study, a small plane having ducted fan which can be tilted for vertical take-off and landing, is analyzed by CFD and its aerodynamic characteristics are compared. Ductef fan aircraft has small range of angle of attack for mininum drag and duct design should be focused for efficient ducted fan aircraft.