• 한국항행학회논문지
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• 제20권6호
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• pp.574-579
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• 2016

쿼드로터는 일반 무인항공기와 달리 구조가 단순하고 그 활용 가치가 매우 높아 많은 사람들의 관심을 받고 있다. 하지만 드론에 대한 관심이 높아짐에 따라 항공 안전사고 또는 분실에 대비한 비행체의 안정성과 위치파악의 중요성이 대두되고 있다. 따라서 본 논문에서는 쿼드로터의 모델링을 수식적으로 유도하여 이를 선형화시켜 간단한 제어기로 모델을 안정화시키고 다양한 센서로부터 얻은 데이터를 필터를 거쳐 기울어진 정도를 파악하여 보다 안정한 호버링이 가능한 추적 시스템을 제안하였다. 개발된 추적시스템은 비행 중인 쿼드로터의 위치를 컴퓨터로 전송해 이를 경로로 나타내어 비행경로를 파악할 수 있고 비행속도, 고도 등의 다양한 정보를 동시에 확인할 수 있게 하였다. 그리고 실제 쿼드로터에 사용되는 센서는 외란과 진동에 의해 정확한 센서 값을 측정할 수 없기 때문에 칼만필터와 상보필터를 통한 센서 결합으로 이를 극복하여 쿼드로터 호버링의 안정성을 PID 제어를 통해 구현하였다. 이를 모의 실험을 통하여 쿼드로터의 속도, 위치, 고도 등의 다양한 정보를 실시간으로 확인하였다.

• 제어로봇시스템학회논문지
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• 제21권1호
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• pp.14-20
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• 2015

This paper describes the design of a robust H-infinity attitude controller for a quad-rotor. The linear model of a quad-rotor was estimated using PEM (Prediction Error Minimization) method with experimental input and output data. To design an attitude controller, an extended plant was constructed by adjusting several uncertainties and weighting functions. An H-infinity controller was obtained by applying H-infinity methodology to the extended plant. Through frequency-domain analysis, it was shown that the designed controller can overcome uncertainties up to 75% of the plant model. The performance and robustness of the controller were verified through time-domain simulation.

• 한국산학기술학회논문지
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• 제15권4호
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• pp.2335-2342
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• 2014

미래 유통 혁신 및 도심에서의 긴급 차량 운행에 도움을 주고자 차량 이동 정보 등이 포함된 실시간 교통 상황 정보 및 긴급 정보 제공 등을 위하여 무인 쿼드로터의 사용하고자 할 경우 무인 쿼드로터의 사용 안전성을 충분히 고려해야 한다. 따라서 본 연구에서는 4개의 모터를 가지고 있고 시스템적으로 구조적 균형이 잘 잡혀있는 무인 쿼드로터 시스템의 안전성 증대를 위하여 도심에서의 안전 착륙 제어에 대한 연구를 무인 쿼드로터 시스템의 비선형 특성을 고려한 운동학 및 동역학적 모델 기반 및 외란이나 시스템 비선형성에 강인한 Fuzzy 제어기를 통하여 진행하고자 하며, 이를 컴퓨터 시뮬레이션을 통하여 분석 하였다.

• 항공우주시스템공학회지
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• 제3권1호
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• pp.36-41
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• 2009

Quad-rotor is one kind of a rotorcraft in Unmanned Aerial Vehicle (UAV), which consists of four rotors in total and fixed-pitch blades located at the four corners. This vehicle is emerging as popular platform for UAV research due to the simplicity of its construction, the ability of hovering and the vertical take-off and landing (VTOL) capability, etc. Because of those specific capabilities, this vehicle can be applied to many fields: search and rescue, mobile sensor networks, fire observation, etc. However a quad-rotor is much affected by the disturbance due to the characteristics of structure. So this vehicle needs attitude control for stabilizing. In this paper, we design the control law for automatic stabilization. The PID controller is used to control a brushless DC motor. And an accelerometer is used to measure the roll and pitch angles of a quad-rotor.

• 한국정밀공학회지
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• 제33권9호
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• pp.707-714
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• 2016

This paper describes analysis results of vibration characteristics and modal test for a small-scale quad-rotor drone. The rotor arm has a slender body with a propeller and motor at its tip. Rotor system generates excitation for an unbalanced mass. Therefore, the drone platform is involved in the possibility of resonance. For advance identification of the possibility of resonance, confirmation of eigen-mode being closest to the propeller operation range is necessary. Material properties of CFRP tubes used for the rotor arm were acquired by finding the natural frequency based on Rayleigh method. A simplified quad-rotor FE model consisting of rotor arm assembly with tip mass was built to perform numerical analysis, and a free-free boundary condition was applied to provide flight status. Modal tests for the actual platform with impact hammer instrument were performed to verify analysis results. Separation margin from hazardous eigen-mode was checked on the propeller operation range.

• 항공우주시스템공학회지
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• 제2권4호
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• pp.19-24
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• 2008

In this study gives detail on the composition and process of Quad-rotor blade Vehicle. It may seem simple but we have many trouble because of many subtleties. Unless designed carefully, it is very difficult to control of stability by reason of disturbances in the air and unbalance in the motor. We want to have a more stable output so add other electronics supplement, and change the battery in oder to increasing thrust. It cannot be done quickly, nor cheaply because it is more difficult than first ideas that control of Quad-rotor. But we complete manufacture of basically controllable vertical takeoff and landing aircraft.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제16권4호
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• pp.318-322
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• 2016

A quad-copter or quad rotor system is an unmanned flying machine having four engines, which their thrust force is produced by four propellers. Its stable control is very important and has widely been studied. It is a typical example of a nonlinear system. So, it is difficult to get a desired control performance by conventional control algorithms. In this paper, we propose the design of a vectored sum defuzzification based fuzzy logic system for the hovering control of a quad-copter. We first summarize its dynamics and introduce a vectored sum defuzzification scheme. And then we design a vectored sum defuzzification based fuzzy logic system. for the hovering control of the quad-copter. Finally, in order to check the feasibility of the proposed system we present some simulation examples.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.1127-1128
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• 2008

In this paper, we propose a control method to improve control performance for a Quad-rotor Unmanned Aerial Vehicle's stabilization. The proposed method is the Fuzzy+I control that contains a fuzzy controller which processes signals from the error and the change of error, and generates the control signal by summing up fuzzy output signal and integral signal. We simulated and experimented on the fuzzy+I control method by implementing Quad-rotor UAV that is able to hovering, for the purpose of verifying the effectiveness of the proposed fuzzy+I control method in comparison with general PID control, and we found out that fuzzy+I controller improved control performance of the system.

• International Journal of Aeronautical and Space Sciences
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• 제12권3호
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• pp.252-259
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• 2011

This paper is focused on dynamic modeling and control system design as well as vision based collision avoidance for multi-rotor unmanned aerial vehicles (UAVs). Multi-rotor UAVs are defined as rotary-winged UAVs with multiple rotors. These multi-rotor UAVs can be utilized in various military situations such as surveillance and reconnaissance. They can also be used for obtaining visual information from steep terrains or disaster sites. In this paper, a quad-rotor model is introduced as well as its control system, which is designed based on a proportional-integral-derivative controller and vision-based collision avoidance control system. Additionally, in order for a UAV to navigate safely in areas such as buildings and offices with a number of obstacles, there must be a collision avoidance algorithm installed in the UAV's hardware, which should include the detection of obstacles, avoidance maneuvering, etc. In this paper, the optical flow method, one of the vision-based collision avoidance techniques, is introduced, and multi-rotor UAV's collision avoidance simulations are described in various virtual environments in order to demonstrate its avoidance performance.

• 전기전자학회논문지
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• 제17권4호
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• pp.440-445
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• 2013

본 논문은 쿼드로터의 최단거리 복귀 시 위치인식을 위해 확장칼만필터를(EKF) 이용한 저가형 GPS/INS 융합시스템과 셀 분할 알고리즘이 결합된 위치추정시스템을 제안한다. 연구에서는 저가형 GPS가 가지는 위치오차와 INS가 가지는 가속도 값의 계속적인 적분으로 인한 누적 오차를 줄이기 위해 확장칼만필터를 이용하여 GPS/INS 융합시스템을 구성한다. 또한 쿼드로터는 원점 복귀 명령 시 최단거리의 경로 지점에 대한 위치 경로 측정이 가능하기 때문에 위치 경로를 기준으로 셀 분할 알고리즘을 적용하여 GPS/INS 결합 데이터 중 실제 위치와 근접한 데이터를 결정함으로써 위치오차를 더욱 줄인다. 본 논문에서 제안하는 기법의 성능은 실외에서 쿼드로터 복귀 중 GPS, GPS/INS 결합, 셀 분할 알고리즘 적용 각각의 실험 결과를 비교함으로써 평가된다.