• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.7
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• pp.370-378
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• 2002

As resent trends in structural construction have been to build taller and larger structures than any time in the past, they have had high flexibility and low damping that can cause large vibration response under severe environmental loading such as earthquakes, winds, and mechanical excitations. The damper with mass and spring is one approach to safeguarding the structure against excessive vibrations. In this paper, the lumped electrical circuit approach of mass/spring system is used to model the mechanical aspects according to the frequency. Therefore, the mass/spring system can be dealt with here and linked with the equivalent circuit of electric linear oscillatory actuator(LOA). Analysis models are two types of vibration control system, active mass damper(AMD) and hybrid mass damper(HMD). AMD consists of the moving coil LOA with mass only The LOA of HMD with mass and spring is composed of the fixed coil and the movable permanent magnet(PM) field part. The PM field part composed magnet modules and iron coke, is the damper marts itself. We Present the motional resistance and reactance of mass/spring system and the system impedance of AMD and HMD according to the frequency.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.3
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• pp.359-364
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• 2013

In order to use a linear vibration motor for the actuator of a haptic interface, the motor must provide a higher reaction rate and longer service life than typical rotational motors with an eccentric mass. In this paper, we propose a linear vibration motor that is equipped with a voice-coil actuator and permanent-magnet springs. To concentrate the magnetic flux in the actuator, a Halbach-style magnetization pattern is used. Permanent-magnet springs replace mechanical springs to help increase the service life. We use the method of equivalent current sheets and the method of images to analyze and model the proposed vibration motor. These methods are validated using finite element analyses and experiments. A prototype motor is designed and fabricated. Tests with the prototype show the feasibility of the proposed linear vibration motor.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.4
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• pp.537-544
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• 2015

This paper provided two types of design method on moving core type LOA and one type of design method on moving coil type LOA, and compared and examined each of its characteristics. In order to conduct parametric design process, voltage equation was used to schematize Lmin/K and L/M map, and the schematized map was used to determine Lmin, K or L, M. In order to meet requirements such as thrust force and input voltage and to satisfy the target values of Lmin, K or L, M, the types and sizes of each type were designed using geometry design process. 2-FEA was conducted for each of the designed model. After examining thrust force based on the location of the mover, Type-1 showed radical change in thrust force as movers moved, and Type-2 and Type-3 showed constant appearance of thrust force. The total volume of the designed LOA model was compared to select the model with highest thrust force density. Also, the weight of the mover for each model was compared in order to select the model that was predicted to have highest mechanical responsiveness and stroke characteristics.

• Structural Engineering and Mechanics
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• v.29 no.5
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• pp.489-504
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• 2008

In piezoelectric flexible structures, the contribution of vibration modes to the dynamic response of system may change with the location of piezoelectric actuator patches, which means that the ability of actuators to control vibration modes should be taken into account in the development of modal reduction model. The spatial $H_2$ norm of modes, which serves as a measure of the intensity of modes to system dynamical response, is used to pick up the modes included in the reduction model. Based on the reduction model, the paper develops the state-space representation for uncertain flexible tructures with piezoelectric material as non-collocated actuators/sensors in the modal space, taking into account uncertainties due to modal parameters variation and unmodeled residual modes. In order to suppress the vibration of the structure, a dynamic output feedback control law is designed by imultaneously considering the conflicting performance specifications, such as robust stability, transient response requirement, disturbance rejection, actuator saturation constraints. Based on linear matrix inequality, the vibration control design is converted into a linear convex optimization problem. The simulation results show how the influence of vibration modes on the dynamical response of structure varies with the location of piezoelectric actuators, why the uncertainties should be considered in the reductiom model to avoid exciting high-frequency modes in the non-collcated vibration control, and the possiblity that the conflicting performance specifications are dealt with simultaneously.

• Journal of IKEEE
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• v.23 no.2
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• pp.517-523
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• 2019

Recently, researches about automobile seat having function to support the comfort to driver and passenger during the driving are conducted in various fields including automobile seat having massage function. The effect of massage depends on the pattern of massage such as time, magnitude, and shape. In this paper, linear motor actuator, which is used as driving method in the automobile massage seat, and electromagnetic analysis method, which is used to improve the magnetic efficiency in the design of autuator, is proposed. Electromagnetic analysis using finite element method is conducted in the design of linear motor actuator. Input voltage shape for massage pattern is calculated by simulation using mathematical model of actuator. Performance test for massage pattern generation is conducted with automobile massage seat having developed actuator and controller. It is verified that developed actuator system is applicable in the automobile massage seat.

• Journal of the Korean Society of Clothing and Textiles
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• v.44 no.6
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• pp.1154-1162
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• 2020

In this study, the soft textile actuator is produced for a smart wearable with the shape memory effects from linear shape memory alloys of Nickel and Titanium using the driving force through the fabrication process. The measurement model was designed to measure dynamic characteristics. The heating method, and memory shape of the linear shape memory alloy were set to measure the operating temperature. A shape memory alloy at 40.13℃, was used to heat the alloy with a power supply for the selective operation and rapid reaction speed. The required amount of current was obtained by calculating the amount of heat and (considering the prevention of overheating) set to 1.3 A. The fabrication process produced a soft textile actuator using a stitching technique for linear shape memory alloys at 0.5 mm intervals in the general fabric. The dynamic characteristics of linear shape memory alloys and actuators were measured and compared. For manufactured soft textile actuators, up to 0.8 N, twice the force of the single linear shape memory alloy, 0.38 N, and the response time was measured at 50 s.

• Journal of Electrical Engineering and Technology
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• v.3 no.3
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• pp.401-407
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• 2008

The dynamic model and displacement control of piezoelectric actuators, which are commercially available materials for managing extremely small displacements in the range of sub-nanometers, are presented. Piezoceramics have electromechanical characteristics that transduce energy between the electrical and mechanical domains. However, they have hysteresis between the input voltage and output displacement, and this behavior is very demanding and complicated. In this paper, we propose a method of designing the control algorithm, and present the dynamic modeling equations that represent the hysteretic behavior between input voltage and output displacement. For this process, the piezoelectric actuator is treated as a second-order linear dynamic system and system constants are determined by the system identification method. Also, a classical PID controller is designed and used to regulate the output displacement of the actuator. To evaluate the performance of the proposed method, numerical simulation results are presented.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.433-438
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• 2003

In this paper we explore the effectiveness of a magnetostrictive actuator(MSA) as a structural control device. A series of numerical and experimental tests are carried out with a simple aluminum beam only supported at each end by the actuator. After the equation of motion of the controlled system is obtained by the finite element method, a model reduction is performed to reduce the numbers of degree of freedom. A linear quadratic feedback controller is realized on a real-time digital control system to damp the first four elastic modes of the beam. Through some tests, we confirmed the possibility of this actuator for controlling beam-like structures.

• Journal of the Korean Society of Industry Convergence
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• v.20 no.5
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• pp.419-424
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• 2017

The purpose of this study is to develop a virtual testbed capable of predicting the functional performance of a linear electromagnetic actuator for a high voltage relay in order to reduce its development costs and time. The virtual testbed is defined by a multiphysics coupling approach in order to consider the complex interactions of multi-domains such as the solenoid model of electromagnets, the mass-spring-damper model of mechanical systems, the electric circuit model for an external control unit, and the thermal model for predicting temperature variations. The performances of the existing high voltage relay were estimated by the virtual testbed, and then the effectiveness and validation of the proposed testbed were discussed in comparison with the experimental test results. This study showed that the virtual testbed can be applied in design, optimization, and investigation of high voltage relays.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.107-112
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• 1998

In this paper, we introduce the design method using CAE(Computer Aided Engineering) which is profitable in the compatibility and standardization of the developed product, and the reduction of construction time and price to develop and design a machine equipment. Particularly, we select the standard model to design or develop from the large machinery to the super precision one, extract the peculiar characters of the model by the close analysis on the physical and technical part, the experiment for the characteristics of objective dimensions by analogical mathematical analysis for previous results, and can induce the design model demanded by user investigating optimal data in the design previous. We present the analogical algorithms and process method of design factors and restriction factors in the systematization design with computer. Then we analyze step functions for each systematization equipment and induce the process of technical data with actuator model.