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압축하중을 받는 압전 작동기로 구동하는 곤충모방 날갯짓 기구의 특성
박훈철(Hoon Cheol Park),구옌쿠옥비엣(Quoc-Viet Nguyen),변도영(Doyoung Byun),구남서(Nam Seo Goo),윤광준(Kwang Joon Yoon) 한국항공우주학회 2008 韓國航空宇宙學會誌 Vol.36 No.11
단일층 압전작동기에 적절한 압축하중을 가하면, 압전세라믹 층에 가해지는 압축 응력에 의한 재료비선형적 특성과 기계적 좌굴현상에 의하여 작동 변위와 작동력이 동시에 향상된다. 본 논문에서는 날갯짓 기구를 압축하중을 받는 단일층 압전 작동기로 구동하는 경우, 날갯짓 각도와 공기력에 어떠한 영향이 발생하는가를 조사하였다. 또한 날개 형상과 수동 날갯 회전 각도가 공기력 발생에 미치는 영향도 실험적으로 조사하였다. 인공 날개를 2차원으로 가정한 전산유체해석을 통하여 얻은 평균 수직력이, 실험으로 얻은 값과 잘 일치함을 확인하였다. A piezoceramic unimoph actuator can produce a relatively larger actuation force and actuation displacement when a proper compressive load is applied during operation, because the compressive stress causes material nonlinear behavior in the piezoceramic layer and triggers mechanical buckling. In this paper, we examined effects of the actuator under compression on the flapping angle and aerodynamic force generation capability. Effects of wing shape and passive wing rotation angle on the aerodynamic force production were also investigated. The average vertical force acquired by a 2D CFD simulation for an artificial wing showed a good agreement with the measured one by the experiment.
A flapper to mimic flapping frequency of a beetle using a piezoceramic actuator
Q-Tri Truong(트롱쾅트리),Q-V. Nguyen(구옌쿠옥비엣),Hoon C. Park(박훈철),Nam S. Goo(구남서),Doyoung Byun(변도영) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
In this paper, we have demonstrated an approach to increase flapping frequency of a previously developed flapper, which is actuated by Lightweight Piezo-Composite Actuator (LIPCA). This is an effort to mimic the flapping motion of Allomyrina Dichotoma, of which flapping frequency is typically 30㎐. For this purpose, the dynamic characteristic of the LIPCA and the parameter study of a four-bar linkage have been studied. The topology of the linkage system was investigated for the amplification of rotation angle and the moment transfer efficiency. Based on the results we suggested a new design of the linkages might provide a higher flapping frequency. The new four-bar linkage system was fabricated and tested to verify the possibility. The optimal flapping frequency of the modified flapper was measured to be about 18㎐. It is about 100% increase compared to the flapping frequency of the previous flapper.
곤충 모방 날갯짓 비행체의 안정적인 수직 이륙 비행 구현
판호앙부(Hoang-Vu Phan),트롱쾅트리(Quang-Tri Truong),구옌쿠옥비엣(Quoc-Viet Nguyen),박훈철(Hoon Cheol Park),변도영(Doyoung Byun),구남서(Nam Seo Goo) 제어로봇시스템학회 2012 제어·로봇·시스템학회 논문지 Vol.18 No.2
This paper demonstrates how to implement inherent pitching stability in an insect-mimicking flapping-wing system for vertical takeoff. Design and fabrication of the insect-mimicking flapping-wing system is briefly described focusing on the recent modification. Force produced by the flapping-wing systems is estimated using the UBET (Unsteady Blade Element Theory) developed in the previous work. The estimation shows that the wing twist placed in the modified system can improve thrust production for about 10 %. The estimated thrust is compared with the measured thrust, which proves that the UBET provides fairly good estimations for the thrust produced by the flapping-wing systems. The vertical takeoff test shows that inherent pitching stability can be implemented in an insect-mimicking flapping-wing system by aligning the aerodynamic force center and center of gravity.