• International Journal of Aeronautical and Space Sciences
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• v.17 no.1
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• pp.120-131
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• 2016

The full results of troubleshooting process related to the flight control system of a tilt-rotor type UAV in the flight tests are described. Flight tests were conducted in helicopter, conversion, and airplane modes. The vehicle was flown using automatic functions, which include speed-hold, altitude-hold, heading-hold, guidance modes, as well as automatic take-off and landing. Many unexpected problems occurred during the envelope expansion tests which were mostly under those automatic functions. The anomalies in helicopter mode include vortex ring state (VRS), long delay in the automatic take-off, and the initial overshoot in the automatic landing. In contrast, the anomalies in conversion mode are untrimmed AOS oscillation and the calibration errors of the air data sensors. The problems of low damping in rotor speed and roll rate responses are found in airplane mode. Once all of the known problems had been solved, the vehicle in airplane mode gradually reached the maximum design speed of 440km/h at the operation altitude of 3km. This paper also presents a comprehensive detailing of the control systems of the tilt-rotor unmanned air vehicle (UAV).

• Journal of the Korean Society for Aviation and Aeronautics
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• v.27 no.3
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• pp.45-53
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• 2019

The purpose of this study is to provide a brief overview of the helicopter pilot training system applied to the Army, and to examine what factors positively affect the successful flight training of helicopter pilots. For this purpose, we analyzed the correlations between various factors such as individual characteristics, selection factors, flight aptitude evaluation, theoretical subjects test, and self-life evaluation. As a result, it was found that only the flight experience was influential on the individual characteristics at the beginning of the training course, and the learning achievement represented by the test of theoretical subjects was positively influenced throughout the flight training course. This reaffirms the fact that an individual's high level of motivation or effort influences his flight training performance. These results are expected to be useful indicators for future development of pilot selection system and pilot training system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.8
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• pp.631-640
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• 2020

Currently, aircraft simulator has drawn a great attention because it has significant advantages of economic, temporal, and spatial costs compared with pilot training with real aircraft. Among the components of the aircraft simulator, flight dynamic model plays a key role in simulating the flight of an actual aircraft. Hence, it is important to verify the fidelity of flight dynamic model with an automated tool. In this paper, we develop a software to automatically verify the fidelity of the flight mechanics model for the efficient development of the aircraft simulator. After designing the software structure and GUI based on the requirements derived from the fidelity verification process, the software is implemented with C # language in Window-based environment. Experimental results on CTSW models show that the developed software is effective in terms of function, performance and user convenience.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.11
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• pp.1130-1137
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• 2006

Relaxed Static Stability(RSS) concept has been applied to improve aerodynamic performance of modern version supersonic jet fighter aircraft. Therefore, the flight control systems are necessary to stabilizes the unstable aircraft and provides adequate handling qualities. The initial production flight control system are verified by flight test and it's always an elements of danger because of flight-critical nature of control law function and design error due to model base design method. These critical issues impact to flight safety, and it could be lead to a loss of aircraft and pilot's life. Therefore, development of an easily modifiable RFCS(Research Flight Control System) capable of reverting to a PFCS(Primary Flight Control System) of reliable control law must be developed to guarantee the flight safety. This paper addresses the concept of SSWM(Software Switching Mechanism) using the fader logic such as TFS(Transient Free Switch) based on T-50 flight control law. The result of the analysis based on non-real time simulation in-house software using SSWM reveals that the flight control system are switching between two computers without any problem.

• Journal of Satellite, Information and Communications
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• v.7 no.2
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• pp.80-86
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• 2012

The software-based satellite simulator has been developed from the start of the project to resolve the restriction and limitation of using hardware-based software development platform. It enables the development of flight software to be performed continuously since initial phase. The satellite simulator emulates the on-board computer, I/O modules, electronics and payloads, and it can be easily adapted and changed on hardware configuration change. It supports the debugging and test facilities for software engineers to develop flight software. Also the flight software can be loaded without any modification and can be executed as faster than real-time. This paper presents the architecture and design of software-based GEO satellite simulator which has hot-standby redundancy mechanism, and flight software development and test under this environment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.3
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• pp.243-256
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• 2015

As a part of the R&D efforts for the hypersonic vehicles, various flight test programs has been carried out using small launch vehicles or sounding rockets. Australian HyShot program is a representative case of the flight test program for scramjet engines carried by international collaborations. A number of hypersonic flight test programs has followed in a similar way. In USA, Falcon HTV-2 was carried by DARPA, X-51A by AFRL and HyFly by ONR. HyCAUSE and HIFiRE were carried in collaboration with Australia. In France, LEA program is on the way similarly to X-51A. Russia, China and India seems like carrying out flight test programs for the development of hypersonic defense system. The goals, technical elements, the status and the relation between the programs were summarized in this paper as a reference for the similar program of the country in the future.

• Aerospace Engineering and Technology
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• v.10 no.2
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• pp.1-10
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• 2011

This is a comparative study of three inertia navigation units and focuses on the verification of reliability about GPS/INS for the SmartUAV(DGNS). Those GPS/INS have been tested using a manned aircraft and an automobile. The comparative aspect of units include details about the GPS positions and the inertia sensor performance. With the flight scenario, the DGNS guarantees the reliability of the navigation operation and performs the flight test for the development of the SmartUAV.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.5
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• pp.349-357
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• 2022

Since the flight control computer of unmanned aerial vehicle (UAV) is a flight critical equipment, it is necessary to ensure reliability and safety from the development step, and a redundancy-based fault management design is required in order to operate normally even a failure occurs. To reduce cost, weight and power consumption, the dual-redundant flight control system design is considered in UAV. However, there are various restrictions on the fault management design. In this paper, we propose the fault detection and isolation designs for the dual-redundant flight control computer to satisfy the safety requirements of an UAV. In addition, the flight control computer developed by applying the fault management design performed functional tests in the integrated test environment, and after performing FMET in the HILS, its reliability was verified through flight tests.

• Aerospace Engineering and Technology
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• v.4 no.2
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• pp.7-14
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• 2005

This paper describes development of automatic flight control system for an unmanned target drone. Current target drone is operated by pilot control of on-board servo motor via remote control system. Automatic flight control system for the target drone greatly reduces work load of ground pilot and can increase application area of the drone. Most UAVs being operated nowdays use high-priced sensors as AHRS and IMU to measure the attitude, but those are costly. This paper introduces the development of low-cost automatic flight control system with low-cost sensors. The integrated automatic flight control system has been developed. The performance of automatic flight control system is verified by flight test.

• Journal of Aerospace System Engineering
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• v.13 no.2
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• pp.1-9
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• 2019

This paper elaborates on the directional axis guidance and control algorithm used in mission flight for high altitude long endurance UAV. First, the directional axis control algorithm is designed to modify the control variable such that a strong headwind prevents the UAV from moving forward. Similarly, the guidance algorithm is designed to operate the respective algorithms for Fly-over, Fly-by, and Hold for way-point flight. The design outcomes of each guidance and control algorithm were confirmed through nonlinear simulation of high altitude long endurance UAV. Finally, the penultimate purpose of this study was to perform an actual mission flight based on the design results. Consequently, flight tests were used to establish the flight controllability of the designed guidance and control algorithm.