• Journal of Advanced Marine Engineering and Technology
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• 제28권2호
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• pp.354-360
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• 2004

It is well known that pneumatic actuators convert fluid power into mechanical power with a low efficiency. The pneumatic rotary actuators are used in not only marine winches. but also hoists, agitators, and excavators. The efficiency of pneumatic rotary actuators depends on several factors, such as type of actuator. speed, supply pressure. size and geometry of the actuator. This paper presents an analytical and experimental study of the performance of pneumatic rotary actuators. We investigate all the major aspects of the air flow through a pneumatic rotary actuator and points out the main causes of the low efficiency of the actuator. Therefore the design parameters which can lead to optimum performance are obtained.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.755-761
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• 2003

Recently, the development of mobile devices demands information storage systems to use micro drive devices and cheap media. These should have several characteristics, for example, the subminiature of size, the robustness of shock, the minimum of cost and power consumption, and the removability of multiple applications. A conventional optical disk drive is more suitable for these specifications than the others. The optical storage system of the new generation to use a blue laser and a high numerical aperture (NA) is the perfect candidate for micro optical disk drives. In this paper, the micro actuator that can be applied to a micro optical disk drive is designed by response surface methodology to use a structural analysis and an electro-magnetic analysis. Based on above results, the coarse actuator and fine actuator are designed and improved from the point of view of the size and the power. Consequently, the designs of a micro actuator are proposed through these courses.

• Tribology and Lubricants
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• 제29권1호
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• pp.7-12
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• 2013

Turbine power control devices at a nuclear / thermoelectric power plant lead to failure by creating mechanical shocks and strong vibrations that are due to the strong elasticity of a spring and the inertia of the valve face during its rapid movement to block steam. To ensure durability of the turbine power control device, which is the main component in the power plant, it is necessary to develop a device that can prevent such vibrations. In this study, a cushion mechanism is added to the head of the hydraulic servo actuator, which is a turbine power control device. Moreover, the cushion mechanism, which includes various modifies shapes and orifices is investigated dynamically through modeling and simulations.

• 한국항공우주학회지
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• 제40권6호
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• pp.492-498
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• 2012

DBD(Dielectric Barrier Discharge) 플라즈마 액츄에이터의 설계 파라미터에 따른 특성을 연구하였다. 방전전압, 주파수, 전극의 간격, 폭, 길이, 유전체 두께에 따른 DBD 플라즈마 액츄에이터의 유속 및 소모전력을 측정하였다. 방전전압과 주파수가 클수록 유속과 소모전력은 증가하였다. 전극간격은 클수록 소모전력은 감소하면서 유속은 증가하였으나, 플라즈마 방전을 위해 높은 전압이 요구되었다. 상부전극폭은 좁을수록, 하부전극폭은 넓을수록 일정한 소모전력으로 유속을 증가시킬 수 있었다. 주어진 방전조건과 전극형상에서 DBD 플라즈마 액츄에이터의 성능을 예측할 수 있을 것으로 기대된다.

• 동력기계공학회지
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• 제9권4호
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• pp.162-167
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• 2005

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 are cost less and faster than previous semiconductor processes have been developed for the production of electric paper and RFID(Radio Frequency IDentification). The system proposed in this study prints by spraying the molten metal. And this system consist of a nozzle, heating furnace, operating actuator and an XYZ 3-axis stage. As an operating system, the piezoelectric(PZT) actuator is a very useful tool for position control of the metal printing system. However, the PZT actuator has a hysteresis nonlinearity due to the ferroelectric characteristics of the PZT element. This hysteresis causes problem position control characteristics in the system 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. In order to reduce the hysteresis nonlinearity of the PZT actuator, this proposed a inverse hysteresis model and a mathematic modeling method that can express the geometric relationship between voltage and displacement. In addition, system identification and PID control methods were examined. Also, it was confirmed that the proposed control strategy gives good tracking performance.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.780-785
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• 2003

Recently the trends in information storage devices need small size, mobility, high capacity, and low power consumption etc. To satisfy those, the development of high performance actuator is an important issue. Compared with general linear actuator for optical disk drive, swingarm type rotary actuator is suitable to design in small form factor and has fast access time for random access. Swingarm actuator is designed considering the structural problem and the actuating force of VCM(Voice Coil Motor). The increase of mass caused by optical components makes vibration problems of swing-arm, therefore resonance frequency should be increased and inertia has to be reduced. ANSYS FEM tool is employed in optimizing swingarm. The VCM is designed using 3-D electro-magnetic analysis, and parameters of magnetic circuit are determined to matte large flux density. The large flux density enables to achieve low power consumption. VCM holder is designed to get the mass balance of total actuator and this balance reduces the magnitude of critical mode relative to pivot bearing, It is expected that swingarm type rotary actuator designed by this method is available to variable type of micro optical disk drives.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.537-541
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• 2002

This paper is about the development of the turbine valve actuator efficiency analysis system for the standard power plants. We developed hydraulic power unit and turbine valve actuator controller. We designed control algorithm for turbine valve actuator, implemented and verified it at the industrial plants.

• 동력기계공학회지
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• 제2권2호
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• pp.60-66
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• 1998

Positioning performance with a normal pneumatic positioning system, is mainly affected by friction force on the actuator and nonlinear characteristics of the control valve. We proposed a positioning system which is composed of a pneumatic actuator and high speed control valve. for accurate and speedy positioning. Driving piston on the actuator is mounted with externally pressurized air bearings to clear the friction force. This paper studies a method in order that improves positioning ability of the pneumatic positioning system considering the nonlinear characteristics of the control valve and the actuator.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 1999년도 추계학술발표대회 논문집
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• pp.124-129
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• 1999

In this study, a design method for the flat sound radiator is developed to make new sound radiator system, whose shape is much thinner than that of conventional loudspeaker. Piezofilm (PVDF) is used as actuators of flat sound radiator. To avoid the distortion of sound radiated from flat sound radiator, the frequency response of radiated sound to be flat is taken as the design objective. The electrode pattern and orientation angle of piezofilm actuator is optimized to satisfy the design objective. The formulation is based on the coupled finite element and boundary element method. Genetic algorithm is used in the optimization process, which is useful in the optimization of discrete design variables. Frequency response with optimized piezofilm actuator is made flat enough to satify the design objective. For the enhancement of sound power, double-layered piezofilm actuators are also considered. The sound power with double-layered actuator becomes larger than that with single-layered actuator as expected.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.84.4-84
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• 2002

$\textbullet$ To achieve 3 high power-to-weight ratio, design of 3DOF hip module $\textbullet$ Using parallel mechanism and linear actuator consist of a ball-screw mechanism $\textbullet$ The kinematics analysis for the hip module $\textbullet$ A kinematic index to measure actuator power are introduced. $\textbullet$ It is demonstrated throught simulation that incorporation of redu ndant actuator into the hip module