• Journal of Satellite, Information and Communications
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• v.10 no.3
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• pp.32-37
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• 2015

Unmaned Aerial Vehical(UAV) is a flight which is automatically flying by remote control on th ground. However UAV has an advantage of control that is easy, but has an disadvantage of not hovering. By comparison, quadcopter which is one of the UAV is easily operated. Also quadcopter has hovering function and high stability. In this paper, we propose stable flight algorithm associated PID(proportional-integral-derivative) control with fuzzy contorl to implement stable quadcopter system. After getting a positioning information of the drone, This proposed system is implemented for stable flight through flight attitude control using gyro and acceleration sensor. We also propose the flight mode system to hover drone with GPS sensor.

• Journal of Aerospace System Engineering
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• v.8 no.3
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• pp.47-54
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• 2014

This is a research on the method of how to improve stall characteristics for the small general aviation airplanes to meet the FAR part 23 requirements. This research is based on the experience of certification flight tests of KC-100 airplane for Korea type certification. KAS/FAR Part 23.201/203 are the stall characteristics requirements. 23.201 requires to show the stable stalling tendency of the wings level stall and 23.203 requires to show the stable stalling tendency of stall characteristics during turning flight. In this paper, the stall characteristics requirements, improvement methods and flight test experience of KC-100 airplane for type certification.

• Journal of Advanced Navigation Technology
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• v.8 no.2
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• pp.112-119
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• 2004

This paper proposes an attitude determination GPS/INS integrated system scheme for a UAV and presents experimental flight test results. The proposed system is designed as a part of an autopilot system and comprises a GPS attitude determination receiver, an off-the-shelf inertial measurement unit (IMU), and a navigation computer unit (NCU). UAV requires accurate attitude information for stable automatic flight control. The proposed system can provide accurate attitude information for the flight control computer (FCC) so that stable automatic flight control can be achieved. In order to verify the performance of the proposed scheme, an integrated navigation system has been developed. In order to evaluate the developed navigation system, the flight test has been performed. In the flight test, the developed system was shown to provide the position, the velocity and the attitude satisfactorily enough for stable flight control. The accuracy of the attitude information of the developed system was confirmed by comparing attitude of vertical gyro.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.6
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• pp.16-27
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• 2020

For the operation of the scramjet engine in the wide flight range, the design of the inlet must show stable performance in various flight conditions. In this study, the design methods of a 2D fixed inlet for stable performance in wide flight ranges of Mach number 4 to 6 and angle -6° to 6°, is performed. After proposing the design method and design focus, performance prediction and analysis were performed by various initial compression angles and design Mach numbers, which are essential design factors in total pressure recovery and inlet capture area ratio in the wide flight range. Based on the analysis results, we present the selection criteria for the two main design elements to represent stable performance in the wide flight range.

• Electronics and Telecommunications Trends
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• v.38 no.3
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• pp.11-19
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• 2023

Drones, which were early operated by remote control, have evolved to enable autonomous flight by combining various sensors and software tools. In particular, autonomous flight of drones was possible since the application of GNSS-RTK (global navigation satellite system with real-time kinematic positioning), a precision satellite navigation technology. For instance, unmanned drone delivery based on GNSS-RTK data was demonstrated for pizza delivery in Korea for the first time in 2021. However, the vulnerabilities of GNSS-RTK should be overcome for delivery drones to be commercialized. In particular, jamming in the navigation system and low positioning accuracy in urban areas should be addressed. Solving these two problems can lead to stable flight, takeoff, and landing of drones in urban areas, and the corresponding solutions are expected to establish a hybrid positioning technology. We discuss current trends in hybrid positioning technology that can either replace or complement GNSS-RTK for stable drone autonomous flight.

• Korean Journal of Applied Biomechanics
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• v.13 no.3
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• pp.67-79
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• 2003

The purpose of this study is to investigate the effective skill motion through the kinematic analysis of the Yurchenko Streched motion in new horse vaulting. The subjects in this study were 3 male gymnasts who were ranked as national athletes. After the 3D motion analysis, kinematic variables were analyzed to comparison with the difference between this study and the previous study(Yang, D. Y and Lee, C. S, 1999). As a result, the following conclusions was drawn; 1. In the board contact phase, this study showed a shorten contact time to maintain in condition highly extension of hip and hee angle than the previous study. 2. In the pre-flight phase, this study appeared more shortly flight duration time and horizontal flight displacement than the previous study. 3. In the horse contact phase, the contact duration time and horizontal displacement of COG shortened than the previous study, but appeared to the fast horizontal and vertical velocity and highly extension of shoulder an. 4. In the post-flight phase, a stable horse contact appeared to the increase of the flight duration time and the apex height during the post-flight. And it showed that these results have a stable and good landing.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1864-1866
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• 1997

Uncertainties in the aerodynamic coefficients or time delay effects in implementing an autopilot algorithm can make a Flight Control System(FCS) unstable. When a FCS enters unstable state, the actuator or sensor limiters in FCS make the unstable system not diverge but be in the state of stable limit cycle. If an autopilot recognize the FCS to be in the stable limit cycle phenomenon, it woudl be better to adjust autopilot gains to stabilize the FCS. A novel method to stabilize a FCS using parameter estimation and maintenance of given phase margin is proposed. The method is applied to roll control loop and verified its performance.

• Korean Journal of Applied Biomechanics
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• v.20 no.3
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• pp.311-318
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• 2010

This study examined the double piked dismount among the landing techniques of parallel bars based on three-dimensional motion analysis. Four male national gymnasts were the subjects. This study was performed to provide quantitative data highlighting players strengths and weaknesses to enable more stable landing technique. The variables analyzed were the position and velocity of center of gravity(CG) and angles of shoulder joints, hip joints, and trunk. The results are as follows: S1 secured the height of flight with fast vertical rise. After the easy spin in the air, he conducted a stable landing maintaining a proper hip joints angle. S2, S3, and S4, however, began the backward somersault already before leaving the bars, so they moved backward greatly making it more difficult to achieve a higher flight path. As a result, they couldn't control the velocity of their backward movement at landing. For a stable landing, they have to maintain the negative shoulder angle when rising, minimize both antero-posterioror side-to-side movements by doing a strong tap using hip joints, to secure the height of flight before the somersault. Results also show that at the descent, they should conduct rapid spinning by increasing their shoulder and hip joints to the maximum while controlling their velocity.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.3 no.1
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• pp.37-47
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• 1995

It is very important to determine the performance and operating envelope of engine for aircraft's flight. The basic performance is provided by manufacturer, but installed engine's operating envelop is only determined by flight test. First, this study was measured cylinder head temperature(CHT), exhaust gas temperature(EGT) and oil temperature. At pre-determined altitude and power rate, these temperatures were measured by change of mixture ratio and mixture ratio condition for economic operation and max. power were found. And secondly, with the measured temperatures, possible positions of mixture lever were determined by flight test for stable flight Chang-91 and Lycoming IO-360-A series four cylinders engine with 200 hp was used for this study.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.15 no.4
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• pp.142-147
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• 2007

When the aircraft is developed, several flight tests are performed including stability and controllability, performance and systems, above all the most important part of the flight test is stability test. Stability test is divided into two parts, static stability and dynamic stability. Static stability of the aircraft is typically defined in terms of its initial tendency to return to equilibrium after a disturbance and not included time concept. One of static stability, longitudinal static stability, was addressed here. The longitudinal static stability was studied from the basic theory to the flight test method and also explained data reduction method throughout the flight test. Finally showed how to meet the specifications such as ROC, FAR and MIL-specifications.