• 한국생산제조학회지
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• 제22권2호
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• pp.235-240
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• 2013

This paper presents a disposable microfluidic infusion pump using the restoring force of elastomeric membrane of Polydimethylsiloxane. Microfluidic infusion pump consists of hydraulic resistance control part, elastomeric blister actuator part, drug inlet and outlet. Expanded elastomeric blister actuator continuously pushes liquid in the chamber to outlet. At same time, microchannel diameter near the outlet was controlled by thin elastomeric membrane in hydraulic resistance control part. Eventually flow rate of infused liquid is controlled by air pressure. In experimental study, the amount of the filled liquid in the blister is precisely controlled by the height of the blister. Flow rate of infused liquid could be controlled, that is, controlled release of the drug over time was possible by adjusting hydraulic resistance and restoring pressure with the blister actuator.

• International Journal of Naval Architecture and Ocean Engineering
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• 제13권1호
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• pp.86-101
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• 2021

This study examined the effects of buoy shape and Nonlinear Froude-Krylov force (NFK) on a heaving-buoy-type Wave Energy Converter (WEC). Based on the Maclaurin expansion, the theoretical solutions of the NFK were derived for three different buoy shapes; hemispheric buoy, circular vertical cylinder, and truncated conical cylinder. A hydraulic power take-off system was adopted, and the latching control strategy was applied to maximize the extracted power from the WEC. The nonlinear effects of the Froude-Krylov force and restoring force on the heaving point absorber were investigated by comparing the heave Response Amplitude Operator (RAO) and time-averaged power extraction. The results showed that the conventional linear analyses were overestimated by up to 50% under the high amplitude wave condition. The latching control strategy was the most effective when peak wave period of regular or irregular wave was 0.4-0.45 times the heave natural period of the buoy.

• Structural Monitoring and Maintenance
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• 제3권2호
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• pp.157-174
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• 2016

Based on classical viscoelastic damper, a brand-new damper is designed by the change of simple construction to implement vibration control for both translational vibration and rotational vibration simultaneously. Theoretic analysis has been carried out on the restoring force model and the control parameters. Two improved models are presented to obtain high simulation precision. The influence of the size, shape of the viscoelastic material, the ambient temperature and the response frequency on the vibration control effect is analyzed. The numerical results show that the new type viscoelastic damper is capable of mitigating the multi-dimensional seismic response of offshore platform and the response control effect has complicated relations with aforementioned related factors.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.103.2-103
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• 2001

In this paper, we discusses compliant actuators those are made of electrostrictive polymer. Electrostrictive polymer actuators(EPAs) are based on the deformation of dielectric elastomer polymer in the presence of an electric field. We address actual design and fabrication method of an actuator using the electrostrictive polymer. We have developed primitive prototypes of the actuator using elastic restoring force. And they actuators have 1 to 3 DOF, 1 DOF actuators are simple linear actuators and 3 DOF actuator has linear actuation and steering capability. They are simple in structure with lightweight, high trust, force and large stroke. Basic design principles and experimental procedures for confirming their performance will be introduced.

• Earthquakes and Structures
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• 제3권6호
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• pp.821-838
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• 2012

This paper proposes a new three-layer pillar-type hysteretic damper system for residential houses. The proposed vibration control system has braces, upper and lower frames and a damper unit including hysteretic dampers. The proposed vibration control system supplements the weaknesses of the previously proposed post-tensioning vibration control system in the damping efficiency and cumbersomeness of introducing a post-tension. The structural variables employed in the damper design are the stiffness ratio ${\kappa}$, the ductility ratio ${\mu}_a$, and the ratio ${\beta}$ of the damper's shear force to the maximum resistance. The hysteretic dampers are designed so that they exhibit the targeted damping capacity at a specified response amplitude. Element tests of hysteretic dampers are carried out to examine the mechanical property and to compare its restoring-force characteristic with that of the analytical model. Analytical studies using an equivalent linearization method and time-history response analysis are performed to investigate the damping performance of the proposed vibration control system. Free vibration tests using a full-scale model are conducted in order to verify the damping capacity and reliability of the proposed vibration control system. In this paper, the damping capacity of the proposed system is estimated by the logarithmic decrement method for the response amplitudes. The accuracy of the analytical models is evaluated through the comparison of the test results with those of analytical studies.

• Structural Engineering and Mechanics
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• 제61권6호
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• pp.795-806
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• 2017

According to the characteristics of continuous beam bridges, the relative displacement is too large to collision or even girder falling under earthquakes. A device named Cable-sliding Modular Expansion Joints(CMEJs) that can control the relative displacement and avoid collision under different ground motions is proposed. Working principle and mechanical model is described. This paper design the CMEJs, establish the restoring force model, verify the force model of this device by the pseudo-static tests, and describe and analyze results of the tests, and then based on a triple continuous beam bridge that has different heights of piers, a 3D model with or without CMEJs were established under Conventional System (CS) and Seismic Isolation System (SIS). The results show that this device can control the relative displacement and avoid collisions. The combination of isolation technology and CMEJs can be more effective to achieve both functions, but it need to take measures to prevent girder falling due to the displacement between pier and beam under large earthquakes.

• 로봇학회논문지
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• 제13권2호
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• pp.103-112
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• 2018

In this paper, a high performance underwater vehicle which can be manufactured at low cost is designed and fabricated, and its performance is verified through experiments. To improve efficiency, the Myring equation is used to design the appearance and the duct structure including the thruster is planned to increase the propulsion efficiency while reducing the drag force. Through various methods, it is secured stable waterproof performance, and also is devised to have high speed movement and turning performance. The developed underwater vehicle is equipped with a high output BLDC motor to achieve a linear speed of up to 2 m/s and can change direction rapidly with stability through four rudders. The rudders are driven by coupling a timing belt and a pulley by extending the axis of a servo motor, and are equipped at the end of the body to turn heading. In addition, for stable posture control, the roll keeps its internal center of gravity low and maintains its stability due to restoring force. By controlling the four rudders, pitch and yaw are handled by the PID controller and show stable performance. To investigate the horizontal turning performance, it is confirmed that the yaw rate controller is designed and stable yaw rate control is performed.

• 한국정밀공학회지
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• 제22권12호
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• pp.34-41
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• 2005

There is a strong demand fur the contactless transportation device fur a hard disk and silicon wafer without contaminating and damaging them. To fulfill this requirements, A transportation device fur them has been proposed. But the device needs many of costly displacement sensors positioned along the transportation interval and possesses a very complicated controller and driving scheme. To overcome those kinds of drawback, in this paper, we present a very simple and cost-effective transportation device which only consists of a linear guide, very simple electrostatic suspension system and driving circuit of stepping motor. The principle of stable suspension by relay feedback control, derivation of lateral restoring force, the design of transportation system are described, fellowed by the experimental system. Experimental results show that a 3.5-inch hard disk has been transported with a speed of approximately 20mm/s while being suspended stably at a gap of 0.25mm.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 가을 학술발표회 논문집
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• pp.27-33
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• 2004

In this paper, various dynamic model of magnetorheological (MR) damper, is required for describing the hysteresis of MR damper and for their application are investigated to structural control. The dynamic characteristics and control effects of the modeling methods for MR dampers such as Bingham, biviscous, hysteretic biviscous, simple Bouc-Wen, Bouc-Wen with mass element and phenomenological models are studied. Of these models, hysteretic biviscous model which is simple and describes the hysteretic characteristics, is chosen for numerical studies. The capacity of MR damper is determined as a portion of not the building weight but the lateral restoring force.

• Smart Structures and Systems
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• 제17권5호
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• pp.709-724
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• 2016

This study investigates the optimum design parameters of a superelastic friction base isolator (S-FBI) system through a multi-objective genetic algorithm to improve the performance of isolated buildings against near-fault earthquakes. The S-FBI system consists of a flat steel-PTFE sliding bearing and superelastic NiTi shape memory alloy (SMA) cables. Sliding bearing limits the transfer of shear across the isolation interface and provides damping from sliding friction. SMA cables provide restoring force capability to the isolation system together with additional damping characteristics. A three-story building is modeled with S-FBI isolation system. Multiple-objective numerical optimization that simultaneously minimizes isolation-level displacements and superstructure response is carried out with a genetic algorithm in order to optimize S-FBI system. Nonlinear time history analyses of the building with optimal S-FBI system are performed. A set of 20 near-fault ground motion records are used in numerical simulations. Results show that S-FBI system successfully control response of the buildings against near-fault earthquakes without sacrificing in isolation efficacy and producing large isolation-level deformations.