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퍼지 게인스케듈링을 적용한 자동착륙 유도제어 알고리즘 설계: 윈쉬어 환경에서의 착륙
하철근(Cheolkeun Ha),안상운(Sangwoon Ahn) 제어로봇시스템학회 2008 제어·로봇·시스템학회 논문지 Vol.14 No.1
This paper deals with the problem of autolanding for aircraft under windshear environment for which the landing trajectory is given. It is well known that the landing maneuver in windshear turbulence is very dangerous and hard for the pilot to control because windshear is unpredictable in when and where it happens and its aerodynamic characteristics are complicated. In order to accomplish satisfactory autolanding maneuver in this environment, we propose a gain-scheduled controller. The proposed controller consists of three parts: PID controller, called baseline controller, which is designed to satisfy requirements of stability and performance without considering windshear, gain scheduler based on fuzzy logic, and safety decision logic, which decides if the current autolanding maneuver needs to be aborted or not. The controller is applied to a 6-DOF simulation model of the associated airplane in order to illustrate the effectiveness of the proposed control algorithm. It is noted that a cross wind in the lateral direction is included to the simulation model. From the simulation results it is observed that the proposed gain scheduled controller shows superior performance than the case of controller without gain scheduling even in severe downburst and tailwind region of windshear. In addition, touchdown along centerline of the runway is more precise for the proposed controller than for the controller without gain scheduling in the cross wind and the tailwind.
출력기반 적응제어기법을 이용한 틸트로터 항공기의 회전익 모드 설계연구
하철근(Cheolkeun Ha),임재형(Jae-hyoung Im) 한국항공우주학회 2010 韓國航空宇宙學會誌 Vol.38 No.3
본 논문에서는 틸트로터 항공기의 회전익 모드에 대한 자율비행 유도제어 알고리즘을 적응제어기법을 이용하여 설계하는 것이다. 이를 위해 우선 출력기반 근사적 궤환선형화 기법을 통하여 알고리즘의 내부루프를 구성하고 그로부터 발생하는 모델오차를 단일 은닉층-신경망을 적용하여 상쇄하였다. 그리고 리아푸노프 안정성 이론에 따른 적응제어 갱신법칙은 선형 관측기를 기반으로 설계하였다. 나아가 외부루프는 경로점 유도법칙으로부터 생성되는 궤적을 추종하도록 하였으며 특히 엄밀한 자동착륙 궤적추종 성능 향상을 위하여 방향각 및 비행경로각 시선유도법칙을 설계하였다. 틸트로터 비선형 모델 시뮬레이션 결과는 콜렉티브 입력에서 보이는 순간적인 작동기 포화현상 이외에는 만족할 만한 안정성과 추종성능을 보여 주고 있다. This paper deals with an autonomous flight controller design problem for a tilt-rotor aircraft in rotary-wing mode. The inner-loop algorithm is designed using the output-based approximate feedback linearization. The model error originated from the feedback linearization is cancelled within allowable tolerance by using single-hidden-layer neural network. According to Lyapunov direct stability theory, the adaptive update law is derived to run the neural network on-line, which is based on the linear observer dynamics. Moreover, the outer-loop algorithm is designed to track the trajectory generated from way-point guidance. Especially, heading and flight-path angle line-of-sight guidance are applied to the outer-loop to improve accuracy of the landing tracking performance. The 6-DOF nonlinear simulation shows that the overall performance of the flight control algorithm is satisfactory even though the collective input response shows instantaneous actuator saturation for a short time due to the lack of the neural network and the saturation protection logic in that loop.
모델 역변환을 이용한 종운동 자동착륙 유도제어 알고리즘 설계
하철근(Cheolkeun Ha),김병수(Byoungsoo Kim) 한국항공우주학회 2004 韓國航空宇宙學會誌 Vol.32 No.2
본 논문에서는 모델 역변환을 이용한 비선형 종운동 자동착륙 유도제어 로직을 설계하고자 한다. 비행체의 동역학 모델을 특이 섭동법을 이용하여, 시간스케일에 빠른 변수와 느린변수로 구분한다. 외부루프에서는 피치 각속도와 스로틀 입력의 의사제어 입력을 결정하고 내부루프에서는 엘리베이터 입력을 구한다. 최종적인 설계 로직은 6자유도 비행체 모델을 사용하여 평가한다. 본 시뮬레이션에서는 정상수평 비행상태에서 고도 1000(ft)와 속도 250(ft/sec)를 갖고 착륙접근을 시작한다고 가정한다. 시뮬레이션 결과는 지상 기지국으로부터 2.5(deg)로 윗방향으로 생성된 비행경로를 정확히 추종하여 만족스런 성능을 보여준다. 이 결과는 향후 무인비행체의 자동착륙 구현에 적용할 수 있다. This paper deals with a design problem of nonlinear longitudinal automatic landing guidance and control logic using dynamic model inversion. Using singular perturbation, the aircraft dynamics are separated into the sub-dynamics related with the fast time-scale variables and with the slow time-scale variables. In the outer-loop design, the pseudo-controls of throttle level and pitch rate are determined. Also the elevator input to the aircraft is determined in the inner-loop design. The final design logic is evaluated in 6 DOF simulation model of the associated aircraft. It is assumed in this simulation that the aircraft in straight level flight starts approaching at l,000ft of altitude and 250ft/sec of airspeed. The results show the satisfactory automatic landing capability of precise capture of the trajectory beam with 2.5 degree projected upward from the ground station. This logic designed in this paper is applicable to the automatic landing for UAV in the future.
Control and Path Planning of Quadrotor UAV using Fuzzy PID
Deepak Gautam,CheolKeun Ha(하철근) 제어로봇시스템학회 2012 제어로봇시스템학회 합동학술대회 논문집 Vol.2012 No.7
This paper presents the modeling, control strategy and path planning of four-rotor vertical takeoff and landing (VTOL) unmanned air vehicle (UAV) known as Quadrotor. The UAV’s Mathematical model is derived based on Newton-Euler formulation. Motor model is included for the better approximation of system. Aerodynamic, Coriolis, and gyroscopic effect are neglected. Fuzzy-PID is proposed for the pose (position and orientation) control of the vehicle. Conventional approach of controller design is adopted where linear controller is developed based on linearized dynamics and applied to the nonlinear model. Proposed controller utilizes the fuzzy rules and reasoning to tune the PID gains over certain range. Path planning is done using Dijkstra’s algorithm. For provided initial position, destination, environment and obstacles, Dijkstra’s algorithm calculates the shortest route through given environment whilst avoiding obstacles in the path. Proposed algorithms are simulated using Matlab/Simulink environment and results are presented.
Adaptive Image Filtering for Scale Space Corner Detection
Shugata Ahmed(슈가타 아흐메드),Cheolkeun Ha(하철근) 제어로봇시스템학회 2012 제어로봇시스템학회 합동학술대회 논문집 Vol.2012 No.7
Gaussian filters are frequently used for scale space based corner detection to remove noise and local variation as many false corners are detected in presence of them. However, an appropriate smoothing scale should be selected for Gaussian filtering method, which is a difficult task. Moreover, edges are smoothed out in this method, which creates difficulty in corner detection. In this paper, we propose an adaptive filtering method based on the anisotropic diffusion for scale space based corner detectors. A new filtering coefficient was developed. Edges and interior regions were filtered separately by selecting appropriate thresholds. Edges were detected by the Canny edge detector and corners were detected by the Affine Resilient Curvature Scale Space (ARCSS) corner detector. Experimental results demonstrated that the proposed adaptive method can detect more corners in less computational time than that of original ARCSS.