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마이크로 액추에이터의 실제 거동에 대한 FEA 시뮬레이션
이양창(Yang Chang Lee),이준성(Joon Seong Lee) Korean Society for Precision Engineering 2005 한국정밀공학회지 Vol.22 No.1
Micromachines are extremely novel artifacts with a variety of special characteristics. Utilizing their tiny dimensions ranging roughly from 10 to 10³ micro-meters, the micromachines can perform tasks in a revolutionary manner that would be impossible for conventional artifacts. Micromachines are in general related to various coupled physical phenomena. They are required to be evaluated and designed considering the coupled phenomena. This paper describes finite element analysis (FEA) simulation of practical behaviors for the micro actuator. Especially, electric field modeling in micro actuators has been generally restricted to in-plane two-dimensional finite element analysis because of the complexity of the micro actuator geometry. However, in this paper, the actual three-dimensional geometry of the micro actuator is considered. The starting torque obtained from the in-plane two-dimensional analytical solutions were compared with that of the actual three-dimensional FE analysis results. The starting torque is proportional to V², and that the two-dimensional analytical solutions are larger than the three-dimensional FE ones. It is found that the evaluation of micro actuator has to be considered electrical leakage phenomenon.
황경호(Kyungho Hwang),이종수(Jongsoo Lee) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11
Micro Electric-Thermal-Structural actuators fabricated by polysilicon is a kind of thermal actuators widely applied in MEMS. Such actuator works on the basis of the difference of thermal expansion between thin film arm and blade. Since the actuator’s deflection at the tip is directly a function of applied potential difference, the amount of tip deflection can be accurately calibrated by applied voltage. In the present paper, the computational study requires a coupled multi-physics analysis that accounts for interactions between electric, thermal and elastic fields of actuators. The objective of the present study is to conduct the preliminary parameter study of micro actuator to see the effects of how much stress occurs at the critical position on the actuator and how long it takes for the blade to deform as actuation, etc.
윤소남(Sonam Yun),김찬용(Chan-Yong Kim) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5
The purpose of this paper is to improve the hysteresis characteristics of a stack type piezoelectric actuator using system identification and tracking control. Recently, several printing methods that cost less and are faster than previous semiconductor processes have been developed for the production of electric paper and RFID. The system proposed in this study prints by spraying the molten metal, and consists of a nozzle, heating furnace, operating actuator, and an XYZ 3-axis stage, As an operating system, the piezoelectric(PZT) method has very valuable uses. However, the PZT actuator has a very big hysteresis characteristic due to the ferroelectric characteristics of the PZT element. This causes problems in the system position control characteristics and deteriorates the performance of the system. In this study, an investigation was conducted to improve the hysteresis characteristics of the PZT actuator that has an output displacement for the input voltage. The study proposed a inverse hysteresis model, a mathematic modeling method that can express the geometric relationship between voltage and displacement, in order to reduce the hysteresis of the PZT actuator. In addition, system identification and PID control methods were examined
마이크로 펀칭시스템 구현을 위한 심벌변위확대기구의 설계
최종필(JongPil Choi),이광호(KwangHo Lee),이해진(Hye-Jin Lee),이낙규(Nak-Gue Lee),김성욱(Seonguk Kim),주은덕(Andy Chu),김병희(ByeongHee Kim) 한국생산제조학회 2009 한국생산제조학회지 Vol.18 No.1
This paper presents the development of a micro punching system with modified cymbal mechanism. To realize the micro punching, we introduced the hybrid system with a macro moving part and micro punching part. The macro moving part consists of a ball screw, a linear guide and the micro step motor and micro punching part includes the PZT actuators and displacement amplification device with modified cymbal mechanism. The PZT actuator is capable of producing very large force, but they provide only limited displacements which are several micro meters. Thus the displacement amplification device is necessary to make those actuators more efficient and useful. For this purpose, a cymbal mechanism in series is proposed. The finite element method was used to design the cymbal mechanism and to analyze the mode shape of the one. The displacement and mode shape error between the FEM results and experiments are within 10%. A considerable design effort has been focused on optimizing the flexure hinge to increase the output displacement and punching force.
마이크로 연료전지용 강제 호흡형 공기 공급 모듈에 관한 연구
황준영(Hwang, Jun-Young),윤효진(Yun, Hyo-Jin),이상호(Lee, Sang-Ho),강희석(Kang, Heui-Seok),강경태(Kang, Kyun-Tae) 한국신재생에너지학회 2008 한국신재생에너지학회 학술대회논문집 Vol.2008 No.05
The present study conducts a series of experiments to develop a novel air supplying module for a micro fuel cell using piezoelectric linear actuator. An intermittently and operating air breathing module with reciprocating motion of the linear actuator has been suggested in the present study. A test bench for a micro fuel cell system has been constructed to estimate performance of the active fuel cell system using the air supplying module. With the stroke and operating duty as main control parameters, the optimal operating method of the air supplying module has been discussed.
시뮬레이션을 통한 무밸브 마이크로 펌프의 전기-유체-구조 상호작용에 대한 연구
리광철(Guang Zhe Li),구남서(Nam Seo Goo),한철희(Cheol Heui Han) 한국항공우주학회 2008 韓國航空宇宙學會誌 Vol.36 No.1
본 논문에서는 유한요소법을 기반으로 한 소프트웨어 COMSOL Multiphysics를 이용하여 압전 복합재료 작동기를 이용하여 제작한 무밸브 마이크로펌프의 성능을 연구하였다. 압전 마이크로펌프는 4층의 경량 압전 복합재료 작동기, PDMS으로 된 챔버와 2개의 디퓨저로 이루어졌다. 시뮬레이션에서는 압전 재료 영역, 구조 영역과 유체 영역을 완전 연성하여 해를 계산하였다. 물을 유체로 사용하였으며, 유량을 마이크로펌프의 구조적 파라미터에 대하여 계산하였다. 이 연구에 기초하여 보다 성능이 좋은 마이크로펌프를 제시하였다. In this paper, the pumping performance of a piezoelectric valveless micropump is simulated with a commercial finite element analysis software, COMSOL Multiphysics. The micropump developed in the previous work is composed of a 4-layer lightweight piezo-composite actuator (LIPCA), a polydimethylsiloxane (PDMS) pump chamber, and two diffusers. The piezoelectric domain, structural domain and fluid domain are coupled in the simulation. Water flow rates are numerically predicted for geometric parameters of the micropump. Based on this study, the micropump is optimally designed to obtain its highest pumping performance.
열 구동 엑츄에이터와 SU-8을 이용한 마이크로 그리퍼 설계 및 제조
정승호(Seoung-Ho Jung),박준식(Joon-Shik Park),이민호(Min-Ho Lee),박상일(Sang-Il Park),이인규(In-Kyu Lee) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5
A microgripper using thermal actuator and SU-8 polymer was designed and fabricated to manipulate cells and microparts. A chip size of a microgripper was 3 ㎜ × 5 ㎜. The thermally actuated microgripper consisted of two couples of hot and cold arm actuators. The high thermal expansion coefficient, 52 ppm/℃, of SU-8 compared to silicon and metals, allows the actuation of the microgripper. Thickness and width of SU-8 as an end-effector were 26 ㎛ and 80 ㎛, respectively. Initial gap between left jaw and right jaw was 120 ㎛. The ANSYS program as FEM tool was introduced to analyze the thermal distribution and displacement induced by thermal actuators. XeF₂ gas was used for isotropic silicon dry etching process to release SU-8 end-effector. Mechanical displacements of the fabricated microgripper were measured by optical microscopy in the range of input voltage from 0 V to 2.5 V. The maximum displacement between two jaws of a microgripper Type OG 1_1 was 22.4 ㎛ at 2.5 V.
공압 구동형 초소형 벌룬 액추에이터의 변형에 따른 PDMS 탄성체의 표면 점착력 측정
박찬진(Chan-Jin Park),서영호(Young-Ho Seo),김병희(Byeong-Hee Kim),김광섭(Kwang-Seop Kim),김재현(Jae-Hyun Kim) 한국생산제조학회 2010 한국공작기계학회 추계학술대회논문집 Vol.2010 No.-
Transfer printing process is suitable for high-performance flexible electronics since it can incorporate high temperature process without sacrificing flexibility[1,2]. One of the key elements in transfer printing process is an elastomeric stamp with conformal contact and adjustable adhesion with target devices. In this study, we developed a new concept of controllable adhesion mechanism. This concept is realized by fabricating Micro Balloon Actuator (MBA) array on the surface of a elastomeric stamp and the MBA array is controlled by air pressure. In order to validate the proposed concept, we fabricated a MBA array on a PDMS stamp using photolithography and molding process and the adhesion characteristic of the PDMS stamp with the MBA array was measured with varying air pressure using a micro-tribometer. The adhesion force between the PDMS stamp and silica lens slightly increased with the increase of air pressure under a range of 0~80㎪. Under a pressure range of 80~200㎪, the adhesion force rapidly decreased with the increase of air pressure. We also observed that the adhesion force was saturated when the applied air pressure was larger than 200 ㎪. It is noted that the adhesion force between the PDMS stamp and silica lens can be reduced approximately 80% from the original adhesion force under a preload of 50mN and air pressure of 220㎪, and was inversely proportional to the stiffness of PDMS stamp.