• Journal of Institute of Control, Robotics and Systems
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• v.17 no.10
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• pp.967-982
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• 2011

This paper presents a FTNCS (Fault-Tolerant Networked Control System) that can tolerate control surface failure and packet delay/loss in an UAV (Unmanned Aerial Vehicle). The proposed method utilizes the benefits of self-diagnosis by smart actuators along with the control allocation technique. A smart actuator is an intelligent actuation system combined with microprocessors to perform self-diagnosis and bi-directional communications. In the event of failure, the smart actuator provides the system supervisor with a set of actuator condition data. The system supervisor then compensate for the effect of faulty actuators by re-allocating redundant control surfaces based on the provided actuator condition data. In addition to the compensation of faulty actuators, the proposed FTNCS also includes an efficient algorithm to deal with network induced delay/packet loss. The proposed algorithm is based on a Lagrange polynomial interpolation method without any mathematical model of the system. Computer simulations with an UAV show that the proposed FTNCS can achieve a fast and accurate tracking performance even in the presence of actuator faults and network induced delays.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.32 no.1
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• pp.1-9
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• 2024

The unmanned aerial vehicle industry has developed a lot, but the possibility of accidents is increasing due to potential risks. In this study, SHELL models and HFACS were used to analyze unmanned aerial vehicle accidents in the UK and to identify the main causes and characteristics of accidents. The main cause analyzed by the SHELL model was identified as an abnormality in the alarm system. The main cause of the accident analyzed by HFACS was identified as the technical environment. The common cause identified by the SHELL model and HFACS was identified as a mechanical problem of unmanned aerial vehicles. This is due to the lack of accurate information or functionality of the alarm system in the operator interface, which often prevents the operator from responding to sensitive information. Therefore, in order to prevent civil UAV accidents, the stability and reliability of the system must be secured through regular inspections of the UAV system and continuous software updates. In addition, an ergonomic approach considering human interfaces is needed when developing technologies.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.47.6-47
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• 2002

UAV(Unmanned Aerial Vehicle) has become one of the most popular military/commercial aerial robots in the new millenium. In spite of all the advantages that UAVs inherently have, it is not an easy job to develop a UAV because it requires very systematic and complete approaches in full development envelop. The ground test & evaluation phase has the utmost importance in the sense that a well developed system can be best verified on the ground. In addition, many of the aircraft crashes in the flight tests were resulted from the incomplete development procedure. In this research, a verification procedure of the whole airborne integrated system was conducted including the flight management sys...

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.3
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• pp.64-72
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• 2021

Manned-unmanned teaming can be a very promising air-to-air combat tactic since it can maximize the advantage of combining human insight with the robustness of the machine. The rapid advances in artificial intelligence and autonomous control technology will speed up the development of manned-unmanned teaming air-to-air combat system. In this paper, we introduce a manned-unmanned teaming air-to-air combat tactic which is composed of a manned aircraft and an UAV. In this tactic, a manned aircraft equipped with radar is functioning both as a sensor to detect the hostile aircraft and as a controller to direct the UAV to engage the hostile aircraft. The UAV equipped with missiles is functioning as an actor to engage the hostile aircraft. We also developed a combat scenario of executing this tactic where the manned-unmanned teaming is engaging a hostile aircraft. The hostile aircraft is equipped with both missiles and radar. To demonstrate the efficiency of the tactic, we run the simulation of the scenario of the tactic. Using the simulation, we found the optimal formation and maneuver for the manned-unmanned teaming where the manned-unmanned teaming can survive while the hostile aircraft is shot-downed. The result of this study can provide an insight to how manned aircraft can collaborate with UAV to carry out air-to-air combat missions.

• The Journal of Korea Robotics Society
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• v.16 no.3
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• pp.216-222
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• 2021

Recently, various robots are being used for the purpose of structural inspection or safety diagnosis, and their needs are also rising rapidly. Among the structural inspection using robots, a lot of researches has recently been conducted on inspection of various facilities and structures using an unmanned aerial vehicle (UAV). However, since GNSS (Global Navigation Satellite System) signals cannot be received in an environment near or below structures, the operation of UAVs has been done manually. For a stable autonomous flight without GNSS signals, additional technologies are required. This paper proposes the autonomous flight system for structural inspection consisting of simultaneous localization and mapping (SLAM), path planning, and controls. The experiments were conducted on an actual large bridge to verify the feasibility of the system, and especially the performance of the proposed SLAM algorithm was compared through comparative analysis with the state-of-the-art algorithms.

• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.4
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• pp.196-202
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• 2020

Rye, whole-crop barley and Italian Ryegrass are major winter forage species in Korea, and yield monitoring of winter forage species is important to improve forage productivity by precision management of forage. Forage monitoring using Unmanned Aerial Vehicle (UAV) has offered cost effective and real-time applications for site-specific data collection. To monitor forage crop by multispectral camera with UAV, we tested four types of vegetation index (Normalized Difference Vegetation Index; NDVI, Green Normalized Difference Vegetation Index; GNDVI, Normalized Green Red Difference Index; NGRDI and Normalized Difference Red Edge Index; NDREI). Field measurements were conducted on paddy field at Naju City, Jeollanam-do, Korea between February to April 2019. Aerial photos were obtained by an UAV system and NDVI, GNDVI, NGRDI and NDREI were calculated from aerial photos. About rye, whole-crop barley and Italian Ryegrass, regression analysis showed that the correlation coefficients between dry matter and NDVI were 0.91~0.92, GNDVI were 0.92~0.94, NGRDI were 0.71~0.85 and NDREI were 0.84~0.91. Therefore, GNDVI were the best effective vegetation index to predict dry matter of rye, wholecrop barley and Italian Ryegrass by UAV system.

• Journal of Mechanical Science and Technology
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• v.17 no.5
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• pp.776-783
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• 2003

A low speed wind tunnel test was conducted for full-scale model of an unmanned aerial vehicle (UAV) in Korea Aerospace Research Institute (KARI) Low Speed Wind Tunnel(LSWT). The purpose of the presented paper is to illustrate the general aerodynamic and performance characteristics of the UAV that was designed and fabricated in KARI. Since the testing conditions were represented minor portions of the load-range of the external balance system, the repeatability tests were performed at various model configurations to confirm the reliability of measurements. Variations of drag-polar by adding model components such as tails, landing gear and test boom are shown, and longitudinal and lateral aerodynamic characteristics after changing control surfaces such as aileron, flap, elevator and rudder are also presented. To explore aerodynamic characteristics of an UAV with model components build-up and control surface deflections, lift curve slope, pitching moment variation with lift coefficients and drag-polar are examined. The discussed results might be useful to understand the general aerodynamic characteristics and drag pattern for the given UAV configuration.

• Korean Journal of Remote Sensing
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• v.33 no.5_1
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• pp.537-546
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• 2017

This study aims to develop the floating debris detection algorithm using a Unmanned Aerial Vehicle (UAV) and multispectral sensors. In addition, the occurrence range of floating debris was estimated by applying the algorithm. An aerial photograph using an unmanned aerial vehicle was used to generate an orthoimage that can calculate the area. A spectrum survey of water, plants litter, polystyrene foam etc. was conducted. After obtaining spectroscopic characteristics of floating debris and water, the River Floating Debris (RFD) index was calculated. And we detected the floating debris through band combination of sensor using RFD. As a result of the RFD application, accumulation zone of floating debris was confirmed at three sites in the orthoimage. It was estimated that a lot of floating debris was accumulated at 0.82 ha ($8,200m^2$), which is corresponding to 3.6% including the accumulation zone.

• Convergence Security Journal
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• v.17 no.3
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• pp.31-40
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• 2017

UAV (Unmanned Aerial Vehicle) is increasingly used in diverse fields such as disaster, distributi on, and logistics, but it is pointed out that the inadequacy of related laws and invasion of privacy is an obstacle to industrial growth. The regulatory framework for UAV convergence services is pr oposed based on the regulatory framework. From the technical point of view, regulation on archite ctural design, from the market point of view, concurrent operation of services in a limited area, a l egal evaluation based on post-evaluation rather than a pre-regulation under the legislation of visua l information protection law and a social consensus will contribute to the early settlement of UAV -based convergence services.

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.6
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• pp.618-638
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• 2020

An unmanned aerial vehicle(UAV) refers to an aircraft that has all or part of its functions to autonomously fly by grasping the surrounding environment by remote control on the ground without a pilot on board. With the development of unmanned aerial technology, civil/military forces are developing unmanned aerial vehicles for various purposes. In order to control unmanned aerial vehicles from the ground, communication protocols between unmanned aerial vehicles and ground control equipment are required, and civil/military forces have developed and used a photocall for different purposes. In this study, the characteristics of the MAVLink protocol used in the private sector and the STANAG 4586 protocol used in the military are compared/analyzed in detail to find elements to complement each other and to draw improvement measures for protocol unification.