Design and evaluation of a LIPCA-actuated flapping device

Syaifuddin, Moh,Park, Hoon Cheol,Goo, Nam Seo Institute of Physics Publishing 2006 Smart materials & structures Vol.15 No.5

<P>In this paper, we have introduced a flapping wing mechanism actuated by a unimorph piezoceramic actuator, LIPCA (lightweight piezo-composite actuator). In the flapping system, the limited actuation displacement produced by bending motion of the simply supported actuator was transformed into a large flapping angle by using a four-bar linkage system. A wing rotation mechanism was also designed and implemented such that the wing can be passively rotated due to the resultant aerodynamic force during flapping motion. The natural flapping frequency of the device was about 9 Hz, where the maximum flapping angle was achieved. Flapping tests under 4–15 Hz flapping frequencies were performed to investigate the flapping performance by measuring the vertical force and forward force produced. The maximum forces were produced when the flapping device was actuated near the natural flapping frequency. The measured force data indicated that the present flapping system could produce positive average forces in the vertical and forward directions. </P>

Design and Test of Flapping Device Mimicking Insect Flight

Syaifuddin, Moh.,Park, Hoon Cheol,Yoon, Kwang Joon,Goo, Nam Seo Trans Tech Publications, Ltd. 2006 Key Engineering Materials Vol.306 No.-

<P>This paper addresses detail design and demonstration of an insect-mimicking flappingwing mechanism composed of LIPCA (Lightweight Piezo-Composite Actuator) and linkage system that can amplify the actuation displacement of LIPCA. The angular amplification of the linkage system can provide various flapping angles by adjusting the actuation point of the LIPCA. The device can generate flapping frequency ranging from 5 to 50 Hz depending on weight of the wing and linkages. Flapping tests using different wing mass, area, and aspect ratio were performed to investigate the flapping performance. The test results were described and compared with the estimation. It was found that changes in wing mass, area, and aspect ratio result in significant variation of natural flapping-frequency.</P>

Characteristics of an Insect-mimicking Flapping System Actuated by a Unimorph Piezoceramic Actuator

Nguyen, Viet-Quoc,Syaifuddin, M.,Park, H.C.,Byun, D.Y.,Goo, N.S.,Yoon, K.J. SAGE Publications 2008 Journal of intelligent material systems and struct Vol.19 No.10

<P>This study introduces an insect-mimicking flapping-wing system, where the rotation, corrugation, and clapping of insect wings have been mimicked. Unlike most motor-driven flapping systems, the flapping in this system is actuated by a unimorph piezoceramic actuator. The artificial wings are first made of a thin polyethylene sheet and then corrugated. As the wings are assembled through a pitching hinge, they can passively rotate about the hinge during the flapping motion due to the resultant aerodynamic force. The effects of the rotation, corrugation, and clapping of the wings are experimentally explored with respect to the vertical force produced by the flapping system. A smoke-wire flow visualization is also conducted to confirm whether the flapping-wing system can generate leading edge and trailing edge vortices, which are essential for generating lift and thrust in insect flight.</P>

압전작동기 LIPCA로 구동하는 곤충 모방 날갯짓 기구

박훈철(Hoon Cheol Park),모 사이푸딘(Moh Syaifuddin),윤광준(Kwang Joon Yoon),구남서(Nam Seo Goo) 한국소음진동공학회 2005 한국소음진동공학회 학술대회논문집 Vol.2005 No.11

LIPCA 작동기로 구동되는 날갯짓 기구의 설계 및 성능평가

이승식(Seungsik Lee),모 시아푸딘(Moh. Syaifuddin),박훈철(Hoon Cheol Park),윤광준(Kwang Joon Yoon),구남서(Nam Seo Goo) 한국항공우주학회 2005 韓國航空宇宙學會誌 Vol.33 No.12

본 논문에서 LIPCA(Lightweight Piezoceramic Composite Actuator)를 이용한 날갯짓(flapping) 기구의 개발에 관한 최근의 연구진척 사항을 제시하였다. 날갯짓 기구는 여러개의 연결막대를 이용하여 LIPCA의 제한된 작동변위를 커다란 날갯짓 각(flapping angle)이 발생하도록 증폭시켰으며, 패더링 메커니즘(feathering mechanism)을 적용하여 날갯짓과 동시에 날개에 비틀림이 발생하도록 설계되었다. 이 날갯짓 기구의 고유 날갯짓 주파수는 약 9㎐로, 이때 최대의 날갯짓 각이 발생하였다. 제작된 날갯짓 기구의 작동성능을 평가하기 위하여 날갯짓 주파수를 4㎐에서 15㎐까지 변화시키면서 발생되는 양력과 추력을 측정하였으며, 최대 양력과 최대 추력은 고유 날갯짓 주파수 부근에서 계측되었다. In this paper, we present our recent progress in the LIPCA (Lightweight Piezo-Composite Actuator) application for actuation of a flapping wing device. The flapping device uses linkage system that can amplify the actuation displacement of LIPCA. The feathering mechanism is also designed and implemented such that the wing can rotate during flapping. The natural flapping-frequency of the device was about 9 ㎐, where the maximum flapping angle was achieved. The flapping test under 4 ㎐ to 15 ㎐ flapping frequency was performed to investigate the flapping performance by measuring the produced lift and thrust. Maximum Lift and thrust were produced when the flapping device was actuated at about the natural flapping-frequency.

Economics During Global Recession: Sharia-Economics as a Post COVID-19 Agenda

Aryati ARFAH,Fahruddin Zain OLILINGO,S. SYAIFUDDIN,D. DAHLIAH,N. NURMIATI,Aditya Halim Perdana Kusuma PUTRA 한국유통과학회 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.11

This research is a literacy study regarding the implementation and management of the economic role of haria as a new strategy in overcoming the problem of the global financial crisis that has hit the middle of the COVID-19 pandemic. The research method comes from previous studies to compare the capitalist, socialist, and sharia economic systems. In response to various economic uncertainties, both internal and external, the ability to seize opportunities and transform has become the key to economic resilience. Islamic economics can be an alternative in responding to the dynamics of the global and national economy. Several things need to be taken into consideration in fulfilling the sharia economy and the primary strategy chosen must come from the inputs given by the stakeholders, including business actors, associations, regulators as well as experts, and academicians. The primary strategy in implementing the sharia economy also requires the support of various parties in order to develop sustainability. Strengthening regulation and governance is one of the fundamental factors. Optimization of the sharia economy based social sector such as Zakat, Infaq, Sadaqah, and Waqaf can be optimized both for collection and distribution so that the concept of sharing can certainly support the development and the economy both nationally and globally.

The Effects of Managerial Overconfidence and Corporate Governance on Investment Decisions: An Empirical Study from Indonesia

Zaludin ZALUDIN,Buyung SARITA,Dedy Takdir SYAIFUDDIN,Sujono SUJONO 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.10

This research aims to analyze the effects of managerial overconfidence and corporate governance on investment decisions. Besides, it also tries to discover the effect of internal financing mediation between managerial overconfidence and corporate governance on investment decisions. This study employed panel data from 44 manufacturing companies from 2014 to 2019, out of a total of 117, thus the total observations are 264. The hypothesis was verified through structural equation modeling (Smart PLS 2). The study revealed as follows: 1) Managerial overconfidence has a positive and significant effect on internal financing, while corporate governance has a negative and significant effect on internal financing, 2) managerial overconfidence, internal financing, and corporate governance have a positive and significant effect on investment decisions, 3) internal financing partially mediated the effect of managerial overconfidence on investment decisions, However, internal financing does not mediate the effect of corporate governance on investment decisions. The findings in this study will help company managers implement good corporate governance to improve investment efficiency. In addition, managers can reduce the proportion of retained earnings and increase the proportion of dividend payout ratios, and increase the use of external sources of funds in making investments to minimize agency costs and manager’s opportunistic behavior.

곤충 비행원리를 모사한 압전 작동기 구동형 날갯짓 기구의 평가

박훈철(Hoon Cheol Park),모하메드 샤이푸딘(Mohamad Syaifuddin),변도영(Doyoung Byun),구남서(Nam Seo Goo) 한국항공우주학회 2006 韓國航空宇宙學會誌 Vol.34 No.8

본 논문에서는 단일층 압전 작동기로 구동되는 곤충 모방 날갯짓 기구의 실험적 평가의 결과를 제시하였다. 변위 증폭기구의 연결막대 길이와 힌지 위치를 조절하여, 말벌류 곤충의 상향 날갯짓 끝에 발생하는 날개 겹침 (clap)을 모방할 수 있도록 하였다. 또한, 실제 곤충 날개의 단면이 지그-재그형인 것을 모방한 날개를 제작하여 부착하였다. 이 두 가지 추가적인 고안으로 인하여 본 날갯짓 기구는 이전 날개에 비하여 면적이 절반 밖에 되지 않음에도 불구하고 더 큰 양력을 발생할 수 있었다. 본 연구에서는 날개의 겹침, 지그-재그형 단면, 인가전압 파형이 양력 발생에 미치는 영향을 조사하였다. 최종적으로는 디지털 고속카메라를 이용하여, 개선된 날갯짓 기구가 상향 날갯짓과 하향 날갯짓에서 와류를 발생함을 확인하였다. This paper presents experimental evaluation of an insect-mimicking flapping-wing device actuated by a unimorph piezoceramic actuator. Length of each rod and hinge point in the linkage/amplification system are carefully chosen such that the resulting wing motion can mimic clapping of wings in a real insect at the end of upstroke. In addition to this, a pair of corrugated wings are fabricated mimicking zig-zag cross section of a real insect wing. Thanks to the two additional implementation, the improved flapping wing device can generate a larger lift force than the previous model even though area of the new wing is about 50% less than that of the previous wing. In this work, effects of the wing clapping, the wing corrugation, and the input wave form on the lift force generation have been also experimentally investigated. Finally, the vortex generated by the flapping device has been captured by a high speed camera, showing that vortices are produced during up- and down-strokes.