• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.12
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• pp.1207-1222
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• 2004

In this paper, the explicit equations on the power consumption and sensitivity ratio of VCM-type actuator for disk drive are proposed. The power consumption and sensitivity ratio is derived in frequency domain. The power consumption during the track following of the actuator can be described well in frequency domain and it can be used to calculate the total power dissipation of the actuator which is needed to compensate the tracking and focusing errors. Also, the sensitivity ratio of an actuator is derived by using the reference servo of a disk drive and will be used to optimally obtain the performances of the actuator. This sensitivity ratio can persuasively explain the basis of the target performances of the actuator in the considerations of the reference servo. The usefulness of the proposed equations for the sensitivity ratio and power consumption of an actuator is shown by a lot of simulations. In the near future, we will verify the simulation results by experiments.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.12
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• pp.1071-1076
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• 2008

This paper presents the self power generation from vibration using the piezoelectric bimorph actuator. The piezoelectric bimorph actuator was well developed with PZT-PNN-Fe piezoelectric ceramics. As the applied voltage was increased, a linear change of displacement was obtained with a relatively high ratio of 12.53 um/V for the bimorph actuator. Moreover, when the motor's rotational speed was 2000 rpm, the bimorph actuator, which has a resonance frequency of 68 Hz, exhibited the most efficient generation voltage of 10.4 V. This bimorph actuator could make the LED, emitting 60 mW, working successfully. Therefore, it is anticipated that the bimorph actuator will be useful as a power source for the next-generation electronic devices.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3259-3263
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• 2007

This paper describes the proceedings of creating countermeasures after analysis and maintenance be able to conduct operation safely in a power plant. in order to operate the power plant in a stable and reliable way, the best condition of the govemor system can be maintained through the response characteristic analysis of the control device for the pitch blade control hydraulic actuator. The fan pitch blade control hydraulic actuator of a 500MW large-scale boiler is frequently operated under normal operation conditions. Common problems or malfunctions of the pitch blade control hydraulic actuators leads to the decline of boiler thermal efficiency and unexpected power plant trip. The inlet and outlet gas can be controlled by using the fan pitch blade control hydraulic actuator in order to regulate the internal pressure of the furnace and control the frequency in the power plant facility which utilizes soft coals as a power source.

• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.954-958
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• 2012

This paper reports a flexible patch rectenna for wireless actuation of cellulose electro-active paper actuator (EAPap). The patch rectenna consists of rectifying circuit layer and ground layer, which converts microwave to dc power so as to wirelessly supply the power to the actuator. Patch rectennas are designed with different slot length at the ground layer. The fabricated devices are characterized depending on different substrates and polarization angles. The EAPap integrated with the patch rectenna is actuated by the microwave power. Detailed fabrication, characterization and demonstration of the integrated rectenna-EAPap actuator are explained.

• Journal of Drive and Control
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• v.15 no.2
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• pp.32-37
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• 2018

The power plants use turbine output control devices to supply or shut off steam to high pressure and low-pressure steam turbines connected to generators. This turbine output control device is driven by a hydraulic servo actuator. The gas flows into the hydraulic servo actuator during periodic inspection or normal operation, and the resulting adiabatic compression of the gas raises the internal temperature of the actuator to $500^{\circ}C$. This temperature increase causes the seals to burn and show wear and tear, resulting in failure. In this study, an air vent valve was installed to allow gas inside the hydraulic servo actuator to flow large quantities of air at the beginning of the operation and after the periodic inspection. Gas was passed through for only minute flow during normal operation of the power plant. By applying the air vent valve, it improves the reliability of the hydraulic servo actuator by discharge the gas appropriately to improve the life of the seal.

• Journal of KSNVE
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• v.11 no.2
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• pp.257-264
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• 2001

In this research, piezoelectric smart structures are applied for SEA(Statistical Energy Analysis), which is well known approach for high frequency analysis. A new input power measurement based on piezoelectric electrical power measurement is proposed and compared with the conventional method in SEA. As an example, a simple aluminum beam on which piezoelectric actuator is attached is considered. By measuring the electrical impedance and electrical current of the piezoelectric actuator, the electrical power given on the actuator is found and this is In turn converted into the mechanical energy. From the measured value of the stored energy of the beam, the Internal loss factor is calculated and this value shows a good agreement with that given by the conventional method as well as the theoretical value. To compare the coupling loss factor, L-shape beam system which consists of a aluminum beam subsystem and a steel beam subsystem coupled by three pin is taken as second example. The input power and stored energy of each subsystem are found by the proposed approach. The coupling loss factor found by the electrical input power obtained from the piezoelectric actuator exhibits similar trend to the value found by the conventional method as well as the theoretical value. In conclusion, the use of SEA for high frequency application of piezoelectric smart structures is Possible. Especially, the input power that is essential for SEA can be found accurately by measuring the electrical input power of the piezoelectric actuator.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1463-1468
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• 2007

This paper presents the possibility of the electric energy harvesting using piezoelectric actuator which is operated by geared motor. The geared motor consisting of oval shape cam and speed controller was operated in the range of 40${\sim}$172rpm. The PZT actuator of $36L{\times}13W{\times}0.6H$ was used for energy harvesting and the results of the theoretical model were verified by comparing it with the measured response of a experimental setup. Experimental study for obtaining the optimal operating conditions, such as displacement variation of the PZT actuator and motor speed variation, was achieved. A power of 0.02mW at the geared motor speed of 172rpm and the PZT actuator maximum displacement of $500{\mu}m$ was measured. In this study, it was confirmed that the wind power can be used for MEMS based sensor operating and windmill health monitoring one.

• Transactions of The Korea Fluid Power Systems Society
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• v.6 no.4
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• pp.24-32
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• 2009

For a design of on/off solenoid actuator for valve actuating, designer must have the experimental knowledge as well as general electromagnetic formulas to design object. It is possible for theoretical knowledge to do the out-line design, but it is impossible to optimal design without experimental knowledge which only can be achieved through many repeated experiments. In addition, in present on/off type solenoid actuator field, the smaller, lightening, lower consumption power, high response time are effected as the most important design factor. So, experimental knowledge is more needed for optimal design of solenoid actuator. In this study, we derived the governing equations for optimal design of on/off solenoid actuator for valve actuating and developed a design program composed electromagnetic theories and experimental parameter values for inexperienced designers. And we proved the propriety of this program by experiments.

• Transactions of The Korea Fluid Power Systems Society
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• v.4 no.2
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• pp.28-33
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• 2007

In the power plant facility which use soft coal as a power source the fan pitch blade control hydraulic actuator is used to control the inlet and outlet gas to regulate the internal pressure of the furnace and control the frequence. Sometimes malfunctions of this equipment lead to the decline of boiler thermal efficiency and unexpected power plant trip. In order to localize the fan pitch blade control hydraulic actuator specially for the 500MW large scale boiler, Analysis and modelling of the system is carried out mathematically. The responses of the system are examined by using matlab simulation fur the variation of the major parameters in view of reverse engineering. Consequently the validity of the established parameters are examined.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.3
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• pp.207-215
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• 2017

The superior performance of the spherical actuator is establishing a new trend in the industry. Spherical actuators can perform multiple degrees-of-freedom (DOF) motions by using only one actuator. Therefore, a multi-DOF device using the spherical actuator can reduce weight and simplify the structure. This paper proposes a new spherical actuator that uses the operational principle of a rotational voice coil motor. The effectiveness of the actuator is verified through 3-D finite element method.