• 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 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.

• 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 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.

• Korean Journal of Applied Biomechanics
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• v.15 no.2
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• pp.119-127
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• 2005

The purpose of this research helps to make full use for perfect performance by grasping the defects of Ropez motion performed by athlete CSM who was under the training for the 28th 2004 Athene Olympic Garnes, and by presenting complementary methods. For the better Ropez motion which had been performed by CSM for the 1st dispatch selection test and the final for the 28th Athene Olympic Game was analyzed with 3-dimensional cinematographic method. Here are the conclusions: 1. During the board contact phase, powerful kicking and rapid forward flexion motion of upper body make increasing vertical velocity of C. O. G and enlarging body angle. 2. It was indicated that rapid forward flexion motion of upper body during the board contact phase get a large body angle in horse take-off. 3. rapid forward flexion motion of upper body during the board contact phase makes a longer time at horse contacting phase. It showed that this result increased velocity of horse take-off causing by powerful blocking motion. 4. Increasing of air-borne height during pre- flight phase, makes a higher C. O. G; and larger angle of hip, angle of knee and body angle in the landing phase. And it revealed that these results have a stable landing.

• 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.

• Journal of Aerospace System Engineering
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• v.3 no.3
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• pp.17-23
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• 2009

KARI SUAV (Smart Unmanned Aerial Vehicle) program is currently on the phase of ground and flight test. SUAV is a tilt rotor aircraft having the capability of vertical take-off/landing and high speed forward flight. The SUAV rotor system is 3-bladed, gimbaled hub type, which is not common for conventional helicopter configuration. In this paper, detailed procedure and method of rotor pitch rigging, tracking and balancing were described based on the experience of SUAV ground test.

• Journal of Aerospace System Engineering
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• v.15 no.4
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• pp.21-29
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• 2021

As global environmental regulations have been strengthened, the eco-friendly market has grown rapidly. In the field of aircraft, research on electric vertical take-off and landing aircraft that can enter city centers and perform personal air transportation using electric propulsion is ongoing. For aircraft using electric propulsion methods to operate reliably, electric power thrust systems are a key factor. Electric aircraft require a high power density for propulsion systems with strict limits on volume and weight. The efficient control of inverter systems is essential for achieving high power density. Therefore, in this paper, the characteristics of inverters and motors were analyzed through simulations based on the space vector pulse width modulation (PWM) and discontinuous PWM methods for controlling inverter systems.