• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.647-650
• /
• 2017

As the necessity of development of supersonic vehicle increases, securing an aerodynamic data from low to high altitude is requested for flying vehicles crusing in various high-tech environment. Therefore our research team built equipment by improving heating device of Model Aerodynamic Facility(MAF) of Konkuk University to simualte a real gas environment. Guided weapon system and temperature and velocity distribution according to the flow that is produced from the pier of supersonic vehicle is planned to be researched by using this equipment.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.37 no.11
• /
• pp.1104-1111
• /
• 2009

In the low altitude, mission of the aircraft is restricted by a variety of threats such as anti-air missiles and terrain obstacles. Especially, aircraft have always a risk of ground collision near terrain. In this study, to effectively solve this problem, we developed the flight path generation algorithm that is considered the terrain avoidance. In this flight path generation algorithm, waypoints that should be passed by the UAV are selected first. The waypoints are located in the middle of the terrain obstacles. Then, physically meaningful waypoints sets are classified by Dijkstra algorithm. The optimal waypoint guidance law based on the optimal control theory is applied to produce trajectory candidates. And finally the minimum control energy trajectory is determined.

• Science of Emotion and Sensibility
• /
• v.11 no.3
• /
• pp.365-374
• /
• 2008

Using flight simulator tasks with 48 air force cadets, this research examined the effects of pilots' flight skill and self-esteem on risk-taking behavior in the context of social comparison with their cohorts. Flight skill and self-esteem were assessed for individual cadets and three conditions of social comparison (upward-, downward-, and no-comparison) were devised. Flight simulator situations inappropriate for further approach or landing were designed to assess pilots' risk-taking behavior. Weather conditions in the simulator were inadequate to make a landing and the recommended strategy was to break off the approach and attempt a go-around. In this experiment, pilots' risk taking was measured in terms of their approach altitudes; the lower approach altitudes indicative of the higher risk-taking. Our results showed interaction effects of flight skill, self-esteem, and social comparison on risk-taking behaviors. For pilots who were either high or low in both self-esteem and flight skill, social comparison had no effect on risk-taking behavior. However, pilots with high self-esteem but low flight skill showed more risk-taking behaviors in social comparison conditions. And, pilots with low self-esteem but high flight skill showed risk-aversive behaviors in the downward-comparison condition.

• Journal of Advanced Navigation Technology
• /
• v.22 no.6
• /
• pp.537-544
• /
• 2018

A national comprehensive aviation test center is being constructed for the purpose of flight tests for development and modification of aircraft or flight inspections for the development of navaids. Flight testing is a high-risk task, so strict risk management processes are required prior to operation. In addition, since the flight test center is subject to the airdrome regulations under the current law, the introduction of the safety management system will enhance safety as usual in ordinary airports. The establishment of a safety management system based on ICAO criteria is an optimal means of ensuring safe and effective operation of the test center and may mitigate the risks that may arise during flight testing. This paper focuses on risk assessment and mitigation required for safety management at the flight test center. We conducted risk assessments on the flight hazards identified in the previous study. Then the high risk group of hazards were selected and risk mitigation techniques such as avoidance, reduction, acceptance, and control were applied.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.31 no.9
• /
• pp.88-93
• /
• 2003

This Paper described the simulation program development for helicopter. In the design of flight control system to accomplish some special missions like UAV, it is important to minimize the execution time obtaining a linear model from nonlinear model that is used for design of controller. The first step for this kind of purpose is to complete a nonlinear model that contains full dynamic characteristics. The second step is to get the trim values that are obtained from the nonlinear model by solving an algebraic equation. And then stability and control derivatives are derived through hovering to forward flight by numerical perturbation that will be used for linear model for a specified flight condition. The software program(HeliSim) is developed by using MATLAB GUI and will provide easy modeling procedure. The suggested method in this paper is much more simpler than any other method like a fully scale helicopter model. The advantage of our suggested method will reduce the computational time due to simple formula to extract a linear model from nonlinear model that will be beneficially used for flight control system of unmanned helicopter by some reduction of computational load.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.48 no.7
• /
• pp.497-504
• /
• 2020

A technique was developed for analysis on sonic boom created by supersonic flight and for prediction of its sound level and atmospheric propagation characteristics. It is of great importance to anticipate sound level of sonic boom because it causes environmental issue. For that purpose, the simplified sonic-boom prediction method was applied to calculate sound pressure according to physical properties and flight information of the object and distance to measurement site, in this study. Propagation characteristics of shock wave emanated from a flying object was analyzed by using line-of-sight vector and ray tracing method which dealt with refraction of wave due to atmospheric density distribution along altitude. Predicted results agreed well with measured data from real flight.

• Aerospace Engineering and Technology
• /
• v.1 no.1
• /
• pp.141-146
• /
• 2002

During dynamic flight by propulsion of rocket engine, in the atmosphere, the attitude control of flight vehicle can be accomplished by the aerodynamic fin actuator. But, in the outer space, the method of TVC(Thrust Vector Control) is only depend on for it. There are many systems which were developed for TVC. In our research, among them we adopted gimbal engine actuation system which could control the vector of thrust by swivelling rocket engine connected by gimbal. There are electro-hydraulic, electro-mechanical and pneumatic system which can be used as gimbal engine actuation system, but the electro-hydraulic system that has high ratio of output power to mass is preferred for the high power system. In this note, we made a mathematical model of the electro-hydraulic gimbal engine actuation system for the TVC of KSR-III in detail and on the base of this model we performed a simulation study. And then, we verified the model by making a comparison between the simulation and the experiments on the real system.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.38 no.2
• /
• pp.137-148
• /
• 2014

A multi-rotor is an autonomous flying robot with multiple rotors. Depending on the number of the rotors, multi-rotors are categorized as tri-, quad-, hexa-, and octo-rotor. Given their rapid maneuverability and vertical take-off and landing capabilities, multi-rotors can be used in various applications such as surveillance and reconnaissance in hostile urban areas surrounded by high-rise buildings. In this paper, the unified dynamic model of each tri-, quad-, hexa-, and octo-rotor are presented. Then, based on derived mathematical equations, the operation and control techniques of each multi-rotor are derived and analyzed. For verifying and validating the proposed models, operation and control technique simulations are carried out.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.49 no.12
• /
• pp.971-980
• /
• 2021

Recently popularized drone technologies have revealed that low-cost small unmanned aerial vehicles(UAVs) can be a significant threat to prevailing power by operating in group or in swarms. Researchers in many countries have tried to utilize integrated swarm unmanned aerial system(SUAS) in the battlefield. Agency for Defense Development also identified four core technologies in developing SUAS: swarm control, swarm network, swarm information, and swarm collaboration, and the authors started researches on swarm control and network technologies in order to be able to operate vehicle platforms as the first stage. This paper introduces design and integration of SUAS consisting of small fixed-wing UAVs, swarm control and network algorithms, a ground control system, and a launcher, with which swarm control and network technologies have been verified by flight tests. 19 fixed-wing UAVs succeeded in swarm flight in the final flight test for the first time as a domestic research.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2022.10a
• /
• pp.594-596
• /
• 2022

This paper relates to a system for pre-processing high-definition images acquired through a camera mounted on an unmanned aerial vehicle(UAV) and transmitting them to a server through a mobile communication network. In the case of the existing UAV system for image acquisition service, the acquired image was stored in the external storage device of the camera mounted on the UAV, and the image was checked by directly moving the storage device after the flight was completed. In the case of this method, there is a limitation in that it is impossible to check whether image acquisition or pre-processing is properly performed before directly checking image data through an external storage device. In addition, since the data is stored only in an external storage device, there is a disadvantage that data sharing is cumbersome. In this paper, to solve the above problems, we propose a system that can remotely check images in real time. Furthermore, we propose a system and method capable of performing pre-processing such as geo-tagging and transmission through a mobile communication network in addition to image acquisition through shooting in an UAV.