• Journal of the Korean Society for Precision Engineering
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• v.17 no.3
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• pp.39-46
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• 2000

In this paper, the analysis of dynamic characteristics and performance investigation of the ER damper are investigated. The ER damper is based on a double rod actuator and an electric field are applied to the moving electrode composed of cylinder and piston. The performance of the ER damper is length of piston electrode field and its velocities. The experimental and calculated results show that the characteristic of the ER damper varies with the magnitude of the electric field.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.2
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• pp.239-245
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• 2013

Modern electric controlled valves are demanded that its solenoid actuator should be smaller size, lighter weight, lower consumption power, and higher response time. For achieving these purposes, the major design factors of solenoid actuator such as magnetic flux density, coil turn numbers, plunger size, bobbin dimension, and etc. are must be optimized. In this study, for optimal design of high speed solenoid actuator for hydraulic servo valve operation, we draw up governing equations which are composed by combination of electromagnetic theories and empirical knowledge, and deduct the values of major design factors by use of them. For more increase the operating speed, voice coil are used as main armature in manufacturing of prototype actuator. And, we have proven the propriety of the governing equations and speed increasing method by experiments using the hydraulic valve assembly adopted the prototype of solenoid actuator.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.253-256
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• 2003

This study presents the combined effect of electric field application and mechanical compressive stress loading on deformation in a multilayer ceramic actuator, designed with stacking alternatively $0.2(PbMn_{1/3}Nb_{2/3}O_3)-0.8(PbZr_{0.475}Ti_{0.525}O_3)$ ceramics and Ag-Pd electrode. The deformation behaviors were thought to be attributed to relative $180^{\circ}$domain quantities which is determined by pre-loaded stress and electric field. The non-linearity of piezoelectricity and strain are dependent upon the young's modulus resulting from the domain reorientation.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1433-1438
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• 2007

Characteristics of a phase change type micro actuator have been studied. The micro actuator has been designed for a micro-pump in an active direct methanol fuel cell(DMFC), consisting of an actuating chamber, a membrane, an electric heater, and a sensor of resistance temperature detector (RTD). In the present study, researches have been focused on the response of the actuator to control algorithm of the heater. The experiments demonstrated that the displacement of the membrane increase with temperature variation which is a function of applied voltage, duty ratio, and operating frequency of heating. The results also showed that operation of the actuator with high voltage at small duty of heating is more efficient than the same power consumption of heating with low voltage at large duty.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.310-313
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• 2005

In recent years, as the robot technology is developed, the researches on the artificial muscle actuator that enable robot to move dexterously like biological organ become active. The widely used materials for artificial muscle are the shape memory alloy and the electro-active polymer. These actuators have the higher energy density than the electro-mechanical actuator such as motor. However, there are some drawbacks for actuator. SMA has the hysterical dynamic characteristics. In this paper, the simulation of anthropomophic robotic hand is performed using ADAMS and the segmented binary control for reducing the hysteresis of SMA is proposed. SMA is controlled by thermo-electric module. The relations between the force and the hysteresis are developed to verify the validity of the suggested method.

• The Journal of the Acoustical Society of Korea
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• v.22 no.3
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• pp.202-207
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• 2003

For medical ultrasonic transducer, phase-weighting method has been used for controlling focal length with electric circuit at each vibrating element. However, the electric circuit is complex as the number of vibrating elements is increased. In this paper, we fabricated line-focus transducer with a bimorph-type piezoelectric actuator. The polyvinylidene fluoride (PVDF) piezoelectric type polymer film is used for transmitting and receiving of ultrasonic signal. Using this transducer, focal length of the transducer can be controlled mechanically by changing voltage of the actuator. It is confirmed that focal length of the transducer can be controlled in range of 1095 to radius of curvature.

• Journal of Power System Engineering
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• v.9 no.4
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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.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.6
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• pp.403-410
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• 2000

This paper deals with a study to improve the performance of Moving Coil type Linear Oscillatory Actuator (MC-LOA) considering unbalanced magnetic circuit. MC-LOA has an unbalanced magnetic circuit due to its asymmetric structure. In this type of LOA, the airgap flux density tends to have different magnitude along mover's displacement and the current directions. The above property causes eccentric of displacement center and interferes with the proper oscillation of LOA. Therefore, this paper presents two models having the unbalanced magnetic circuit and the other balanced by the saturated core. In order to compare the characteristics between the two models, a characteristic analysis for both the basic model and the improved model is performed by their dynamic analysis composed of kinetic and electric equations and Finite Element Method (FEM). The propriety of the improved model is verified through the experimental results.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.4 no.1
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• pp.49-55
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• 2005

This paper presents experiments on the evaluation of characteristics of ER fluids used for vibration control of application in intelligence type process control systems. Dynamic characteristics of the actuator(beam) embedded with the ER fluid can be controlled by changing the strength of the electric field applied on the ER fluids, thus provides a mean to avoid the resonance. In case electric field is supplied to the smart structure with ER fluids, vibration energy is dissipated more than the beam without electric field, because particles in ER fluid form a chain structure in the presence of electric field. The damping and stiffness of the beam with ER fluid are increased when the applied electric field increases. The characteristics of damping and stiffness of the ER fluid with various electric field strength were investigated by conducting a vibration test of the beam with ER fluid. If it applies characteristics of the ER fluids, it will be able to apply in the PLC control system for the vibration which occurs from process system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.114-116
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• 2004

적층형 piezoelectric ceramic actuators를 제작하여 신뢰성을 평가하였다. 소자의 신뢰성 측정을 위하여 3kV/mm, 5kV/mm, 7kV/mm의 정류된 교류전압을 인가하였으며, 실험중 온도와 습도를 일정하게 유지하기 위하여 항온항습조안에서 실험을 실시하였다. 각 실험의 경우에 16개의 소자를 동시에 평가하였으며, 평균파괴시간을 Weibull 통계방식을 이용하여 계산하였으며, Arrhenius model, Power law model을 이용하여 사용 조건하에서 예상수명을 예측하였다.