• Journal of Convergence for Information Technology
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• v.9 no.11
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• pp.118-124
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• 2019

As Unmanned Aerial Vehicles technology has been widespread, various types of unmanned aircraft and mission equipment have been developed in line with mission diversification. Especially in Korea, small unmanned aerial vehicles have been actively developed. In addition, flight control system and mission equipment interface system for effective control of small unmanned aerial vehicles, efficient communication system configuration and operation for transmission to ground operated systems by processing data are required. This paper addresses efficient system structure and operation of communication equipment for missions and control of small unmanned aerial vehicles.

• Journal of Aerospace System Engineering
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• v.9 no.3
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• pp.1-7
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• 2015

In this study, the design of compound smart materials hydraulic pump that can be applied to a small-medium size UAV having a limited space envelope and weight has been conducted. Compound Smart Material Pump(CSMP) proposed in this paper is composed of a pressurize pump and a flow pump for supplying the high pressure and fluid displacement to overcome the disadvantages of the piezoelectric actuator which has a small strain. Though this compound smart material pump has been designed as small size and lightweight as possible, it can sequentially supply the sufficient large flow rate and pressure required for the brake operation. For the design of CSMP, about 2,700 kg (6,000 lb) class fixed wing manned aircraft was selected. Based on the established requirements, the design of the CSMP have been done by strength, vibration, and fluid flow analysis.

• Journal of Aerospace System Engineering
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• v.16 no.6
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• pp.74-80
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• 2022

The utilisation of small drones is becoming increasingly widespread particularly in the military sector. In this study, STANAG 4586, a standard interface for military unmanned aerial vehicles, was applied to a multicopter-type small drone to examine the suitability of the military system. To accomplish this, a small multi-copter vehicle was designed and manufactured, integrating a flight control computer, ground control system, and data link. Furthermore, flight control and ground control equipment software were developed by applying the STANAG 4586 interface, followed by HILS and flight tests.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.8
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• pp.551-557
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• 2022

LRU (Line Replacement Unit) modifications are often required for military aircraft due to aging. Recently, LRU modifications were proceeded for KA-O (Armed Airborne Controller) by replacing the ejection seat and adding avionic equipment, which made the aircraft's operational CG (Center of Gravity) on fuel consumption curve become out of the range of the specification requested. The off-ranged CG should be corrected by introducing an appropriate method. This study proposes a procedure for revising and verifying the empty weight CG altered due to LRU modification for small military aircraft (e.g., KA-O). In the proposed method, first, the change of empty weight CG of KA-O due to the LRU modifications is comprehensively examined. Then, several ballast masses are added to the engine mount strut to restore the empty weight CG on the fuel consumption curve to a safe operational range. The installations are verified via stress and fatigue analysis for various operating conditions. Considering that open information is not very available for the revision of empty weight CG, this study is valuable because it presents an established procedure for correcting and verifying empty weight CG during aircraft modification.

• Aerospace Engineering and Technology
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• v.13 no.2
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• pp.1-6
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• 2014

Power system of the tilt-duct VTOL aerial robot has been developed. This paper focuses on the power train with small liquid-type engine for the R/C boat and presents the test results with design procedures. The hardware aspects of the power system include details about the hardware configurations for the interfaces with the vehicle. The ground test and tether test for measuring the thrust performance of vehicle and evaluating the endurance of power train carried out.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.3
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• pp.110-115
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• 2012

For domestic aircraft industry, not mass production of components is limited, small production scale of the order is made by part because many kinds of hundreds of thousands of kinds of small quantity batch production system are taking. But the high reliability and stability are required during the processing because they require high precision parts are required. It is found that when C-axis rotation speed was increased, the diameter of the cutting tool decreased with increasing surface roughness, while the turn-mail feed rate was increased with increasing the surface roughness.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.3
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• pp.218-228
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• 2001

The switched reluctance motor(SRM) has been increasingly used in high-performance servo applications such as electric vehicles, aircraft, and direct-drive robots. The dynamic equations of SRMs are, however, highly nonlinear and this makes it difficult to control SRMs with high performance. In this paper, we propose a new robust current tracking controller for SAMs which can compensate the nonlinear characteristics of SRM(i.e., back-emf and inductance) completely and hence shows perfect tracking performance even with an arbitrary small current control loop gain. Furthermore, even in case that there exist some model uncertainties, our current controller guarantees that the stator currents can track the reference current commands with sufficiently small tracking errors. In order to justify our work, we present the tracking performance analysis and some simulation results.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.491-498
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• 2004

Lift Fan Engines of JAXA's conceptual Jet VTOL aircraft have a very small bellmouse shape air intake, which make some differences in aerodynamic design of the blades. To obtain a better rotor or stator blade design, this paper performs a numerical analysis of the throughflow on a lift fan as a two-dimensional axisymmetrical flow. Based on the last report focusing on the air intake's influence on the throughflow, a more realistic bellmouse air intake case is treated to reconsider the influence on the throughflow by the small bellmouse air intake. Three work input patterns are tested to reduce some problematic influences on the throughflow or blade designs. The obtained result shows one of acceptable blade designs for the lift fan engine.

• Journal of Power Electronics
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• v.14 no.4
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• pp.712-721
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• 2014

This paper introduces a simple grid-voltage-sensorless control scheme for single-phase power factor correction (PFC) boost converters. The grid voltage waveform is obtained based on the dc output voltage, the switching duty ratio, and a phase-lead compensator. In addition, the duty ratio feedback is utilized to obtain the unity input power factor and the zero harmonic current. The proposed control scheme is designed and mathematically analyzed based on a small-signal model of PFC boost converters. To verify the effectiveness of the proposed control scheme, several simulations and experiments are carried out in two applications: an industrial power system with a 60 Hz grid frequency and a commercial aircraft application with a 400 Hz grid frequency.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.17 no.4
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• pp.1-7
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• 2009

The surge control system in unmanned turbojet engine must be capable of accounting uncertainties from engine transient conditions, random fluctuations of key parameters such as air pressure and fuel flow and engine modeling errors. In this paper, taking into consideration of its effectiveness as well as system stability, a fuzzy PI controller is proposed. The role of the fuzzy PI controller is to stabilize the unmanned aircraft upon occurring unexpected engine surge. The proposed control scheme is proved by computer simulation using a linear engine model. The simulation results on the state space model of a small turbojet engine illustrate the proposed control system achieves the desired performance.