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장애물이 산재한 미지의 환경에서 회전익 무인항공기의 계층적 및 통합적 경로생성 및 제어
양광진(Kwangjin Yang) 제어로봇시스템학회 2010 제어로봇시스템학회 각 지부별 자료집 Vol.2010 No.12
This paper presents real time path planning and control algorithms for a rotary wing unmanned aerial vehicle (RUAV) operating in an unknown and cluttered environment. The mission of the RUAV is to navigate from the starting position to the goal position without any prior information about the environment. To achieve this, two approaches are considered in this research, namely InterWeaved Planning and Control (IWPC) and InterGrated Planning and Control (IGPC). In the IWPC strategy, the RUAV replans the path in real time if new obstacles are detected in the environment via its on-board sensors and then generates a control action to track this path. In the IGPC strategy the RUAV generates a control input to head for the goal point while avoiding obstacles without generating a path. Simulation results show that both the IWPC and the IGPC methods can achieve the mission successfully in a cluttered environment.
강제진동 기법을 이용한 무미익 비행체의 동안정 미계수 측정
양광진(Kwangjin Yang),정형석(Hyoungseog Chung),조동현(Donghyun Cho),안은혜(Eunhye An),고준수(Joonsoo Ko),홍진성(JinSung Hong),김용덕(Yongduk Kim),이명섭(MyungSup Lee),허기봉(Gi-Bong Hur) 한국항공우주학회 2016 韓國航空宇宙學會誌 Vol.44 No.7
본 연구에서는 강제진동 기법을 이용하여 람다형상을 갖는 무미익 무인기의 동안정 미계수를 측정하였다. 강제진동 기법은 시험모델을 일정한 크기의 각 변위로 진동시키면서 항공기에 작용하는 공력의 시간이력(time history) 데이터를 측정하고, 입력진동 대비 공력데이터의 위상차와 진폭을 추출함으로써 비행체의 동안정 미계수를 계산하는 방법이다. 본 연구에서는 롤, 피치, 요 방향으로 각각 진동시킬 수 있는 실험 장치를 설계, 제작하여 국내 최초로 무미익 항공기의 동안정 미계수 측정 시험을 수행하였다. 롤 댐핑 동안정 미계수 측정 결과, 진동 주파수와 진동의 크기가 증가하여도 동안정 미계수의 경향성은 동일하게 나타나며, 전반적으로 측정 받음각 구간에서 안정한 특성을 보였다. 피치 댐핑 동안정 미계수의 경우 작은 진동 주파수에서 동적으로 더 안정해지며, 받음각 15o 이상에서는 동적으로 불안정해지는 경향성을 보였다. 각 시험데이터들은 반복성 시험을 통해 데이터의 신뢰성을 검증하였으며, 본 연구에 적용된 강제진동 기법이 무미익 항공기의 동안정 미계수를 성공적으로 측정할 수 있음을 확인하였다. In this experimental study, the dynamic stability derivatives of a tailless lambda-shape UAV are estimated from time history data of aerodynamic moments measured from the internal balance while the test model is forced to oscillate at given frequencies and amplitudes. A 3-axis forced oscillation apparatus is designed to induce decoupled roll, yaw, pitch oscillations respectively. The results show that the roll damping derivatives remain stable at the entire range of angle of attack tested, whereas the pitch damping derivatives become unstable beyond 15° angle of attack. The amplitude and frequency have little impact on roll damping derivatives while the smaller amplitude and frequency of oscillation improves the pitch stability. The yaw damping derivative values are fairly small as expected for a tailless configuration. The results indicate that the proposed methodology and test apparatus area valid for estimating the dynamic stability derivatives of a tailless UAV.
양광진 ( Yang Kwangjin ) 공군사관학교 2019 空士論文集 Vol.70 No.-
본 논문은 경로계획 분야에서 샘플링 기반의 대표적인 방법인 RRT(Rapidly-exploring Random Tree)를 이용한 연구이다. 경로계획에서는 통상적으로 점유격자지도를 이용하여 장애물의 위치를 표현하는데 본 연구에서는 여러 정보가 융합된 확률지도를 이용하였다. 따라서 경로의 안전유무는 장애물과의 충돌이 아닌 확률값으로써 나타나게 된다. 본 연구에서 무인자동차가 가지는 동역학적 특성은 스플라인 기반 RRT를 이용하여 충족하고, 최적성은 RRT*의 재결합 특성을 통해 구현하였다. 모의실험 결과는 스플라인 기반 RRT*가 여러 상황에서 확률지도에서 성공적으로 구현 가능함을 보여준다. This paper presents an optimal reactive RRT(Rapidly―exploring Random Tree) path planning which is a typical algorithm in sampling based method. Generally, occupancy grid map is used to express the location of obstacles but an probabilistic map is applied in this research which fuses several information. Therefore, the safety of the path is expressed not by the collision but by the probability. In this research, the dynamic characteristic of the unmanned ground vehicle is satisfied by the spline-based RRT, and the optimality of the path is realized by the rewiring property of the RRT*. The simulation results show that the spline-based RRT* which uses probabilistic map can be successfully applied in various situations.
블레이드 손상에 따른 이축식 터보팬 엔진의 동적 안정성 해석
김시태(Sitae Kim),정기현(Kihyun Jung),이준호(Junho Lee),박기현(Kihyun Park),양광진(Kwangjin Yang) 한국트라이볼로지학회 2020 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.36 No.2
This paper presents a numerical study on the rotordynamic analysis of a dual-spool turbofan engine in the context of blade defect events. The blades of an axial-type aeroengine are typically well aligned during the compressor and turbine stages. However, they are sometimes exposed to damage, partially or entirely, for several operational reasons, such as cracks due to foreign objects, burns from the combustion gas, and corrosion due to oxygen in the air. Herein, we designed a dual-spool rotor using the commercial 3D modeling software CATIA to simulate blade defects in the turbofan engine. We utilized the rotordynamic parameters to create two finite element Euler–Bernoulli beam models connected by means of an inter-rotor bearing. We then applied the unbalanced forces induced by the mass eccentricities of the blades to the following selected scenarios: 1) fully balanced, 2) crack in the low-pressure compressor (LPC) and high pressure compressor (HPC), 3) burn on the high-pressure turbine (HPT) and low pressure compressor, 4) corrosion of the LPC, and 5) corrosion of the HPC. Additionally, we obtained the transient and steady-state responses of the overall rotor nodes using the Runge–Kutta numerical integration method, and employed model reduction techniques such as component mode synthesis to enhance the computational efficiency of the process. The simulation results indicate that the high-vibration status of the rotor commences beyond 10,000 rpm, which is identified as the first critical speed of the lower speed rotor. Moreover, we monitored the unbalanced stages near the inter-rotor bearing, which prominently influences the overall rotordynamic status, and the corrosion of the HPC to prevent further instability. The high-speed range operation (>13,000 rpm) coupled with HPC/HPT blade defects possibly presents a rotor–case contact problem that can lead to catastrophic failure.