• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1996년도 춘계학술대회논문집; 부산수산대학교, 10 May 1996
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• pp.130-135
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• 1996

This paper presents a proof-concept investigation on the active vibration control of two hybrid smart structures (HSSs). The first one is consisting of a piezoelectric film (PF) actuator and an electro-rheological fluid(ERF) actuator, and the other is featured by a piezoceramic (PZT) actuator and a shape memory alloy (SMA) actuator. For the PF/ERF hybrid smart structure, both the increment of the damping ratios and the suppression of the tip deflections are evaluated in order to demonstrate control effectiveness of the PF actuator and ERF actuator and the hybrid actuation. For the PZT/SMA hybrid smart structure, the PZT actuator takes account of the high frequency excitation, while the SMA actuator exerts large vibration control force. The experimental results exhibit superior abilities of the hybrid actuation systems to tailor elastodynamic responses of the HSS rather than a single class of actuation system alone.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.73-76
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• 2007

Electro-Active paper (EAPap) is a new smart material that has a potential to be used in biomimetic actuator and sensor. It is made by cellulose that is abundant material in nature. EAPap is fascinating with its biodegradability, lightweight, large displacement, high mechanical strength and low actuation voltage. Actuating mechanism of EAPap is known to be the combined effects of ion migration and piezoelectricity. However, the electromechanical actuation mechanisms are not yet to be established. This paper presents the modeling of the actuation behavior of water infused cellulose samples and their composite dielectric constants calculated by Maxwell-Wagner theory. Electro-mechanical forces were calculated using Maxwell stress tensor method. Bending deflection was evaluated from simple beam model and compared with experimental observation, which result good correlation with each other.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1173-1178
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• 2005

This paper proposes an IPMC actuating system with a bio-mimetic function. EMG signals generated by an intended contraction of muscles in forearm are used for the actuation of the IPMC. To obtain higher actuation force of the IPMC, the single layered as thick as 800 [${\mu}$m] or multi-layered IPMC (Nafion) of which each layer can be as thick as 178 [${\mu}$m] are prepared. The experimental results using an implemented IPMC control system show a possibility and a usability of the bio-mimetic artificial muscle.

• 한국소음진동공학회논문집
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• 제17권12호
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• pp.1179-1183
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• 2007

Electro-Active paper(EAPap) is a new smart material that has a potential to be used in biomimetic actuator and sensor. It is made by cellulose that is abundant material in nature. EAPap is fascinating with its biodegradability, lightweight, large displacement, high mechanical strength and low actuation voltage. Actuating mechanism of EAPap is known to be the combined effects of ion migration and piezoelectricity. However, the electromechanical actuation mechanisms are not yet to be established. This paper presents the modeling of the actuation behavior of water infused cellulose samples and their composite dielectric constants calculated by Maxwell-Wagner theory. Electro-mechanical forces were calculated using Maxwell stress tensor method. Bending deflection was evaluated from simple beam model and compared with experimental observation, and which result in good correlation with each other.

• 제어로봇시스템학회논문지
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• 제22권11호
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• pp.960-966
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• 2016

This paper proposes a new concept of a soft and wearable upper-limb exoskeleton. A novel actuation principle, called the twisted string actuation principle, is implemented to make it lightweight, soft, and therefore easily wearable. Its power transmission mechanism and harness are designed to be soft and wearable, yet have enough control accuracy for rehabilitation. In addition to force transmission optimization, a speed enlargement mechanism is newly introduced in order to increase the contraction speed of the twisted string actuation mechanism by sacrificing the unnecessarily large gear reduction ratio of the twisted string mechanism. A prototype has been tested for mirroring therapy, and the feasibility of the proposed mechanism has been shown through a sufficiently accurate tracking performance.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.913-914
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• 2017

액체로켓엔진 개발 과정에서 중량을 절감하고 구조 신뢰성을 증가시키기 위해서는 엔진 시스템에 대한 구조 해석이 필요하다. 발사체는 비행 중 자세제어를 위해 엔진의 TVC (thrust vector control) 구동기의 변위를 변화시켜 연소기를 회전하여 추력의 방향을 제어한다. 본 연구에서는 연소기 김발을 하는 75톤급 액체 로켓 엔진에 대하여 TVC 구동 전/후의 정적 구조 해석을 수행하고 비교하였다.

• 로봇학회논문지
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• 제19권1호
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• pp.45-52
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• 2024

This paper introduces an approach to enhance the performance of magnetic manipulation systems for microrobot actuation. A variety of eight-electromagnet configurations have been proposed to date. The previous study revealed that achieving 5 degrees of freedom (5-DOF) control necessitates at least eight electromagnets without encountering workspace singularities. But so far, the research considering the influence of iron cores embedded in electromagnets has not been conducted. This paper offers a novel approach to optimizing electromagnet configurations that effectively consider the influence of iron cores. The proposed methodology integrates probabilistic optimization with finite element methods (FEM), using Bayesian Optimization (BO). The Bayesian optimization aims to optimize the worst-case magnetic force generation for enhancing the performance of magnetic manipulation system. The proposed simulation-based model achieves approximately 20% improvement compared to previous systems in terms of actuation performance. This study has the potential for enhancing magnetic manipulation systems for microrobot control, particularly in medical and microscale technology applications.

• Structural Monitoring and Maintenance
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• 제5권2호
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• pp.297-311
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• 2018

Plate and shell structure is widely applied in engineering, i.e. building roofs, aircraft wings, ship platforms, and satellite solar arrays. Its vibration problem has become increasingly prominent due to the tendency of lightening, upsizing and flexibility. As a new smart material with great actuating force and toughness, macro-fiber composite (MFC) is composed of piezoelectric fiber and epoxy resin basal body, which can be directly pasted onto the surface of plate and shell and is suitable for vibration control. This paper deduces the actuation equation of MFC coupled plate in different boundary conditions, an equivalent finite element modeling method is proposed which uses MFC actuating force as the applied excitation, and on this basis the active control simulation and experiment of MFC over plate and shell structure vibration are accomplished. The results indicate that MFC is able to implement effective control over plate and shell structure vibration in multi-band range. The comparison between experiment and simulation proves that the actuation equation deduced herein, effective and practicable, can be applied into the simulation calculation of MFC vibration control over plate and shell structure.

• Journal of Magnetics
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• 제16권4호
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• pp.363-367
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• 2011

We have designed, fabricated and demonstrated a novel micro-system for programmable magnetic actuation using magnetic elliptical pathways on Si substrates. Lithographically patterned soft NiFe ellipses are arranged sequentially perpendicular to each other as stepping stones for the transport of magnetic beads. We have measured the magnetization curve of the ellipsoid ($9\;{\mu}m{\times}4\;{\mu}m{\times}0.1\;{\mu}m$) elements with respect to the long and short axes of the ellipse. We found that the magnetization in the long axis direction is larger than that in the short axis direction for an applied field of ${\leq}$ 1,000 Oe, causing a force on carriers that causes them to move from one element to another. We have successfully demonstrated a micro-system for the magnetic actuation of biomolecule carriers of superparamagnetic beads (Dynabead$^{(R)}$ 2.8 ${\mu}m$) by rotating the external magnetic field. This novel concept of magnetic actuation is useful for future integrated lab-on-a-chip systems for biomolecule manipulation, separation and analysis.

• 한국항공우주학회지
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• 제45권4호
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• pp.328-341
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• 2017

발사체의 추력벡터제어를 위한 구동장치시스템에서 관성부하를 갖는 전기기계식 위치서보 시스템의 공진 특성과 유연한 기체구조체 지지부의 구조공진이 결합되어 합성공진이 발생한다. 이렇게 발생한 공진은 발사체의 자세제어시스템에 되먹임되어 자세안정성에 영향을 줄 수 있다. 본 논문에서는 발사체의 추력벡터제어를 위한 직구동 방식의 전기기계식 구동장치의 합성공진을 해석하기 위한 모델을 소개하고 합성공진 현상을 저감하여 구동기의 동특성을 개선하는 동적 하중 되먹임 제어기법의 해석 및 시험 결과를 기술하였다.