• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.4
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• pp.343-352
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• 2016

A multi-rotor vehicle is an unmanned vehicle consisting of multiple rotors. A multi-rotor vehicle can be categorized as tri-, quad-, hexa-, and octo-rotor depending on the number of the rotors. Multi-rotor vehicles have many advantages due to their agile flight capabilities such as the ability for vertical take-off, landing and hovering. Thus, they can be widely used for various applications including surveillance and monitoring in urban areas. Since multi-rotors are subject to uncertain environments and disturbances, it is required to implement robust attitude stabilization and flight control techniques to compensate for this uncertainty. In this research, an advanced nonlinear control algorithm, i.e. sliding mode control, was implemented. Flight experiments were carried out using an onboard flight control computer and various real-time autonomous attitude adjustments. The feasibility and robustness for flying in uncertain environments were also verified through real-time tests based on disturbances to the multi-rotor vehicle.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.40.3-40
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• 2002

Unmanned Aerial Vehicle(UAV) needs autonomous flight capability to accomplish various mission objectives. For this objective, the autopilot is a key element in the UAV system design. The principal goal of autopilot is to guide the aircraft under varying external disturbances throughout the mission phases. The external disturbances include gravity effect, wind gust, and other unexpected obstacles. The gust affects the aircraft flight performance to a significant extent. UAV's low speed, light weight, and the absence of human judgment makes un predictable gust more dangerous. Autopilot design in general takes the gust effect into account to satisfy flight performance requirement. In this study..

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2003.10a
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• pp.3-16
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• 2003

After a not-widely-known fact is revealed that Japan is a leading country in production and use of industrial unmanned helicopters, a kind of UAV. The voice command system and the autonomous flight control system with a variety of control algorithms including neural network, robust and adaptive control that have been developed in collaboration between Kyoto University and Yamaha Motor Co., and funded by the Ministry of Education and Science of Japan are described in some detail. Both already-proven and promising future applications of the autonomous unmanned helicopters are given.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.2
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• pp.87-93
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• 2012

In this paper, a formation guidance method for UAVs (Unmanned Aerial Vehicles) to simulate the formation flight of birds proposed. The proposed method solves all issues of approaching for formation, formation keeping, and scarce chance to be collided with each UAV during formation process. Also, we design the feedforward controller to compensate the change of speed and heading for maneuvering of the leader UAV and the feedback controller to consider the response lag of the system. The stability and performance of the proposed controller is verified via numerical simulations of the full 6-Dof model of UAV.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.3
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• pp.264-273
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• 2010

In this work, autonomous formation flight tests of multiple UAVs are experimentally studied. After a guidance and control system for a UAV is designed and tested, PID formation controller for follower UAV is tested using longitudinal and lateral distance feedback. It is shown that more stable and efficient formation guidance system is obtained by using position and attitude of the leader aircraft, which is exploited to calculate virtual waypoint for follower. In order to improve transient response during turn, part of roll command of the leader is added to the guidance command. Finally, autonomous formation flight test results of 3 UAVs are shown by using the best guidance algorithm suggested.

• Journal of Aerospace System Engineering
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• v.15 no.2
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• pp.36-44
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• 2021

Unmanned aerial vehicles (UAVs) are increasingly needed as they can replace manned aircrafts in dangerous military missions. However, because of their low autonomy, current UAVs can execute missions only under continuous operator control. To overcome this limitation, higher autonomy levels of UAVs based on autonomous situational awareness is required. In this paper, we propose an autonomous situational awareness software consisting of situation awareness management, threat recognition, threat identification, and threat space analysis to detect dynamic situational change by external threats. We implemented the proposed software in real mission computer hardware and evaluated the performance of situational awareness toward dynamic radar threats in flight simulations.

• The Journal of Korean Institute of Information Technology
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• v.16 no.12
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• pp.49-56
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• 2018

As the era of the 4th industrial revolution comes, there is a growing interest in the use of UAVs. While various technologies are being developed using drones, controlling flight of drones is the most basic. Hovering control is essential in order to enable autonomous flight, especially during flight control of drones. In this paper, we design drones based on ATmega2560, Sonar, Optical Flow, and acceleration / gyro 6 axis sensor for drones hovering control, and developed horizontal control, altitude control, position tracking and fixed algorithm based on PID control. In this research, in order to measure the objective result of the drone, keeping the altitude immediately after the drone takes off according to the time, measure the movement value until the position is fixed and stable hovering is maintained and compared analyzed. Experimental results show that the drones can stably hover within 4cm horizontal and 2cm vertical from 50cm above the reference coordinates.

• Journal of the Korea Society of Computer and Information
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• v.24 no.8
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• pp.29-35
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• 2019

This paper proposes a UAV equipped with an automatic control system for educational purposes such as navigation flight or autonomous flight. The proposed UAV is capable of automatic navigation flight and it is possible to control more precisely and delicately than existing UAV which is directly controlled. And it has the advantage that it is possible to fly in a place out of sight. In addition, the user may arbitrarily change the route or route information to use it as an educational purpose for achieving the special purpose. It also allows you to check flight status by shooting a video during flight. For this purpose, it is designed to check the image in real time using 5.8GHz video transmitter and receiver. The flight information is recorded separately and used as data to judge the normal flight after the flight. The result of the paper can be flighted along the coordinates specified using GPS information. Since it can receive real-time video, it is expected to be used for various education purposes such as reconnaissance of polluted area, achievement of special purpose, and so on.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.95-99
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• 1998

We introduce an autonomous flying system using a model-helicopter. A feature of the helicopter is that autonomous flight is realized on the low-cost compact model-helicopter. Our helicopter system is divided into two parts. One is on the helicopter, and the other is on the land. The helicopter is loaded with a vision sensor and an electronic compass including a tilt sensor. The control system on the land monitors the helicopter movement and controls. We firstly introduce the configuration of our helicopter system with a vision sensor and an electronic compass. To determine the 3-D position and posture of helicopter, a technique of image recognition using a monocular image is described based on the idea of the sensor fusion of vision and electronic compass. Finally, we show an experiment result, which we obtained in the hovering. The result shows the effectiveness of our system in the compact model-helicopter.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.1
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• pp.54-60
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• 2009

In this paper, a precision landing approach is implemented based on real-time image processing. A full-scale landmark for automatic landing is used. canny edge detection method is applied to identify the outside quadrilateral while circular hough transform is used for the recognition of inside circle. Position information on the ground landmark is uplinked to the unmanned helicopter via ground control computer in real time so that the unmanned helicopter control the air vehicle for accurate landing approach. Ground test and a couple of flight tests for autonomous landing approach show that the image processing and automatic landing operation system have good performance for the landing approach phase at the altitude of $20m{\sim}1m$ above ground level.