• International Journal of Aeronautical and Space Sciences
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• v.13 no.2
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• pp.238-249
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• 2012

Flight test of flapping micro air vehicles (FMAVs) is carried out using an instrumented measurement system to obtain various engineering parameters and hence to assess the flight performance of the vehicles through the data investigation. An indoor flight test facility equipped with a motion capture system and tracking cameras is used for the work presented in this paper. Maneuvers including straight-level flight, ground flapping, takeoff and landing are tested. Spatial position and orientation data are obtained from the retro-reflective tracking markers attached to the vehicles. Subsequent test analysis is carried out by generating performance parameters from raw data and then assessing the flight performance by comparison of the vehicles. The main findings of this work confirm that the test method and procedures presented here enable the systematic numerical data measurement and assessment of the flying performances of these vehicles, and show the applicability for the test and evaluation of general flapping MAVs.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.7
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• pp.525-534
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• 2019

Water rocket is a pressurized liquid propellant rocket that shares the same basic principles of space launch vehicles. Water rockets can be used as an engineering educational material for the liquid rocket principles and the launch vehicle systems, far beyond the scope of K-12 level science education. In this paper, the principles and theories of water rocket propulsion and flight dynamics was investigated at the level of undergraduate rocket engineering classes. Also, the system level design and operation of water rocket is summarized by including the components of launch vehicle, launch pad, payload and recovery as well as altitude measurement methods.

• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.331-335
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• 2017

We present project updates of the next-generation infrared space mission SPICA (Space Infrared Telescope for Cosmology and Astrophysics) as of November 2015. SPICA is optimized for mid- and far-infrared astronomy with unprecedented sensitivity, which will be achieved with a cryogenically cooled (below 8 K), large (2.5 m) telescope. SPICA is expected to address a number of key questions in various fields of astrophysics, ranging from studies of the star-formation history in the universe to the formation and evolution of planetary systems. The international collaboration framework of SPICA has been revisited. SPICA under the new framework passed the Mission Definition Review by JAXA in 2015. A proposal under the new framework to ESA is being prepared. The target launch year in the new framework is 2027/28.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.9
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• pp.678-685
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• 2019

Due to the changes in future war environment and the technological development of the aviation weapon system, it is required to carry out on the analysis of the Manned-Unmanned aerial vehicles Teaming(MUM-T). Conventional manned-unmanned aerial vehicles operate according to the air strategy missions and vehicles' performance. In this paper, we analyze conventional aerial vehicle's mission to derive various kinds of missions of MUM-T after analyzing the unmanned aircraft systems roadmap issued by US DoD and the air strategy of US Air Force. Next, we identify the basic operations of the vehicles to carry out the missions, select the MUM-T based Suppression of Enemy Air Defense missions(SEAD), and analyze the procedure for performing the missions step by step. In this paper, we propose a procedure of the mission in the context of physical space and timeline for the realization of the concept of MUM-T.

• The Korean Journal of Air & Space Law and Policy
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• v.35 no.3
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• pp.65-93
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• 2020

With the development of information and communication technology, the unmanned aerial vehicle industry began to attract attention as a new growth industry as it entered the fourth industrial revolution. As the size of the unmanned aerial vehicles and the scope of airspace vary from small drones to large unmanned aerial vehicles, the developed countries such as USA and Europe are developing plans for the integrated operation of manned and unmanned aerial vehicles. ICAO is also working on amendments to the relevant ICAO annexes to establish international standards and recommendations for unmanned aerial vehicles. Korea also needs to prepare for the integrated operation of manned and unmanned aerial vehicles that will come in the future, and for this purpose, it is necessary to review and revise the national regulation systems for the safe operation of unmanned aerial vehicles. This study analyzes the amendments of related annexes discussed on the Remotely Piloted Aircraft System (RPAS) pannel, and suggests the direction of revision of the Aviation Safety Act for the safe operation of unmanned aerial vehicles in comparison with the existing Aviation Safety Act.

• International Journal of Aeronautical and Space Sciences
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• v.12 no.2
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• pp.163-174
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• 2011

Task assignments of multiple unmanned aerial vehicles (UAVs) are examined. The phrase "task assignment" comprises the decision making procedures of a UAV group. In this study, an on-line decentralized task assignment algorithm is proposed for an autonomous UAV group. The proposed method is divided into two stages: an order optimization stage and a communications and negotiation stage. A genetic algorithm and negotiation strategy based on one-to-one communication is adopted for each stage. Through the proposed algorithm, decentralized task assignments can be applied to dynamic environments in which sensing range and communication are limited. The performance of the proposed algorithm is verified by performing numerical simulations.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.2
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• pp.91-97
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• 2012

This paper presents a state space model of a two quadrant chopper and PWM inverter-fed Interior Permanent Magnet Synchronous Motor (IPMSM) drive system and its application to hybrid vehicles. The drive system has two different state equations for motoring and regenerating action. This paper presents a common state equation by using State Space Averaging method. Using this model of the IPMSM drive system, detailed simulation and controller design of the drive system, including PWM inverter switching, are given. The validity of this model and usefulness, according to a comparison among Maximum Torque/Ampere control, Maximum Torque/Flux control, and Maximum Efficiency optimization, are confirmed from simulation results.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.3
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• pp.101-112
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• 2021

SpaceX shows various strategies such as constructing various payload portfolio through the reuse of Falcon 9 and Falcon Heavy, constructing the launch vehicles using one type of engine, the transition from kerosene engine to methane engine, and the use of 3D printing. In this study, launch vehicle proposals that can cover a variety of payloads and trajectories from KOMPSAT to GEO-KOMPSAT were constructed, and ten launch vehicles using kerosene gas generator cycle engine, kerosene staged-combustion cycle engine, and methane staged-combustion cycle engine were reviewed. Of the ten launch vehicles, the reusable launch vehicle using a 35-ton methane engine was rated as the best in terms of development potential.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.1
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• pp.1-10
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• 2010

Design and performance evaluation of $H_2O_2$ monopropellant thrusters to be used at reaction control of space launch vehicles were presented in this paper. Design thrust level was determined as 100, 250 Newton which is nominal thrust level for commercial space launch vehicles. Qualification thruster models including solenoid valves were developed after the reactor design were evaluated at engineering thruster models. Each thruster was evaluated by measurement of characteristic velocity, thrust, specific impulse, and pulse response times at sea level test condition.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.11
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• pp.1860-1867
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• 2016

In this paper, first, a linearized modeling of a phase shift full-bridge converter used in chargers of electric vehicles is derived by using state-space approach and transfer functions from the duty ratio to output voltage and the inductor current are also verified. second, control systems for the output voltage and the inductor current are designed using the root locus technique. It is illustrated by experimental results that the control performance on the output variables is satisfied with the designed digital control system based on a automobile qualified 32-bit microcontroller.