• Journal of the Korean Institute of Intelligent Systems
• /
• v.19 no.5
• /
• pp.635-640
• /
• 2009

In real system application, the obstacle avoidance system for the autonomous control of the underwater flight vehicle (UFV) operates with the following problems: it has local information because the sonar can only offer the obstacle information in a local detection area, it requires a continuous control input because the system that has reduced acoustic noise and power consumption is necessary, and further, it requires an easy design procedure in terms of its structures and parameters. To solve these problems, an intelligent obstacle avoidance algorithm using the evolution strategy (ES) and the fuzzy logic controller (FLC), is proposed. To verify the performance of the proposed algorithm, the obstacle avoidance of UFV is performed. Simulation results show that the proposed algorithm effectively solves the problems in the real system application.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.8
• /
• pp.181-189
• /
• 2019

An aircraft power distribution device distributes and controls the power generated by the generator and provides overcurrent protection. There are many defect phenomena that make AC power distribution impossible during flight, which poses a problem in because some electronic equipment cannot be operated. We describe a process of deriving the root cause of defects by using vibration testing equipment to simulate the vibration conditions during aircraft flight, which result in defects. The results show that the cause of the defect is internal wiring damage caused by the vibration of the contactor of the AC power distribution device. Therefore, the shape of the contactor was improved to solve this problem. We also improved the test procedure by performing defect detection tests using vibration testing equipment to detect a faulty contactor. As a result of the improvements, a component certification test and flight test proved that the defect phenomena of the AC electrical master box were improved.

• Journal of Aerospace System Engineering
• /
• v.13 no.4
• /
• pp.43-49
• /
• 2019

In this study, a test equipment which enables to feed endothermic fuel which is heated in the inside and outside environment of a high-speed vehicle and evaluate the heat exchangers' performance was designed and manufactured. For smooth operation of the test equipment, a test procedure that supplied endothermic fuel at high temperatures was established. The catalyst performance test was conducted based on the supply condition of the endothermic fuel and the amount of heat absorbed was analyzed. The validation of the test equipment was proved by comparing the results of catalytic reaction with the previous studies under similar reaction condition. This test equipment can be utilized in the endothermic reaction tests of catalyzed endothermic fuel under various conditions.

• Journal of Advanced Navigation Technology
• /
• v.25 no.1
• /
• pp.78-83
• /
• 2021

Due to rapidly increasing air traffic congestion and airspace restrictions, the International Civil Aviation Organization (ICAO) is urging all aircraft to use SBAS by 2025, in order to implement Performance-based navigation to increase airspace capacity. In line with this, research and development of Korean-style SBAS, which reflects the characteristics of Korea's airspace environment, continues in Korea. Since there is no flight inspection procedure for performance testing and verification of SBAS in Korea yet, this paper analyzes FAA, ICAO Regulations, and laws enacted by the Ministry of Land, Infrastructure and Transport to derive essential evaluations and parameters of Korean SBAS, and presents the optimal design using RTK-DGPS as a position fixing system.

• Journal of Aerospace System Engineering
• /
• v.17 no.1
• /
• pp.79-87
• /
• 2023

To design a control law of an aircraft, an accurate aircraft dynamic model is required. To obtain an aerodynamic database (DB) to build a dynamic model, a large number of wind tunnel tests are typically required. However, when flight test data of target aircraft exist such as in the process of unmanned conversion of a manned aircraft, an aircraft dynamic model can be obtained through a parameter estimation method and a DB tuning procedure. This paper describes a nonlinear model construction process and a verification method for KC-100 OPV aircraft. Flight data compatibility analysis was performed to determine suitability of the estimation method application. Linear model estimation was performed using the maximum likelihood estimation method. Results of aerodynamic DB tuning process and verification applying the FFS standard to the nonlinear model constructed are presented.

• Journal of Advanced Navigation Technology
• /
• v.28 no.1
• /
• pp.37-43
• /
• 2024

National aircraft are subject to exceptions under the International Civil Aviation Convention. Each country must ensure the safety of civil aircraft through reasonable consideration (due regard). Accordingly, the Aviation Safety Act of Korea also includes an exception for national aircraft. However, Korea Coast Guard aircraft are legislated to be subject to the law on five provisions. As Korea Coast Guard aircraft operate under the application of these provisions of international and domestic laws, they will be required to control flight procedures from China's civil air traffic control when flying over provisional action zone, which is international waters in the West Sea. China's demand is a major limiting factor in protecting the safety of the people of Korea, which is the original mission of Korea Coast Guard aircraft, and through this study, countermeasures to solving these problems at the national level were suggested.

• The Journal of the Acoustical Society of Korea
• /
• v.39 no.4
• /
• pp.351-363
• /
• 2020

Launch vehicles are subject to airborne acoustic loads during atmospheric flight and these effects become pronounced especially in transonic region. As the vibration due to the acoustic loads can cause malfunction of payloads, it is essential to predict and reduce the acoustic loads. In this study, a complete process has been developed for predicting airborne vibro-acoustic environment inside the payload pairing and subsequent noise reduction procedure employing acoustic blankets and Helmholtz resonators. Acoustic loads were predicted by Reynolds-Averaged Navier-Stokes (RANS) analysis and a semi-empirical model for pressure fluctuation inside turbulent boundary layer. Coupled vibro-acoustic analysis was performed using VA One SEA's Finite Element Statistical Energy Analysis (FE-SEA) hybrid module and ANSYS APDL. The process has been applied to a hammerhead launch vehicle to evaluate the effect of acoustic load reduction and accordingly to verify the effectiveness of the process. The presently developed process enables to obtain quick analysis result with reasonable accuracy and thus is expected to be useful in the initial design phase of a launch vehicle.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.25 no.4
• /
• pp.24-30
• /
• 2017

Obstacle defines all fixed and mobile objects, or parts thereof, that are located on an area intended for the surface movement of aircraft or extend above a defined surface intended to protect aircraft in flight or stand outside those defined surfaces and that have been assessed as being a hazard to air navigation. Aircraft operations are based on electronic supporting systems using radio frequencies to assist pilots. These frequencies can receive outside interference that change their courses or power, such as distortion, attenuation or reinforcements by an obstacle. This is a preliminary case study that shows the relation of instrument flight procedures and the degree of interferences introduced by a planned obstacle, which is a main bridge post, within the service volume of the radio navigation aids. For the purpose of this study, the case airport's data and it's VOR/DME and ILS systems' limitations are analyzed, as well as the relation of interferences between the obstacle and navigation aides were reviewed with the internal regulations in Korea.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.37 no.1
• /
• pp.105-112
• /
• 2009

For the purpose of facing battle damage that a fighter is subject to in combat, following recovery procedures such as damage assessment, repair design and structural integrity evaluation are investigated. A sample study is presented on the battle damage of F-15 ECS bay, which is comprised of damage assessment and repair design based on ABDR(Aircraft Battle Damage Repair) skills and work procedure complying with AFTO(Air Force Technical Order) forms. Further, the flight safety of repaired structure is validated and the time the permanent repair should be done is estimated through the evaluation of structural integrity such as the calculation of static strength and fatigue life.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2005.11a
• /
• pp.191-195
• /
• 2005

Propellant remains as outage at engine shutdown contributes no useful impulse to the rocket and produces an unwanted increase in burnout weight. Minimization of outage, is therfore is a basic consideration in attaining the maximum performance capability of my bipropellant liquid rocket. This paper present the calculation procedures of outage and optimum loading propellant mass. And some control methods and measurement techniques for outage are presented.