• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.7 s.178
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• pp.1801-1809
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• 2000

A study on the topology optimization of Hard-Disk-Driver(HDD) actuator arm in free vibration is presented. The purpose of this research is to increasse the natural frequency of the first lateral mode of the HDD actuator arm under the constraint of total moment of inertia, so as to facilitate the position control of high speed actuator am. The first lateral mode is an important factor in the position control process. Thus the topology optimization for 2-D model of the HDD actuator arm is considered. A new objective function corresponding to multieigenvalue optimization is suggested to improve the solution of the eigenvalue optimization problem. The material density of the structure is treated as the design variable and the intermediate density is penalized. The effects of different element types and material property functions on the final topology are studied. When the problem is discretized using 8-node element of a uniform density, the smoothly-varying density field is obtained without checker-board patterns incurred. As a result of the study an improved design of the HDD actuator arm is suggested. Dynamic characteristics of the suggested design are compared computationally with those of the old design. With the same amount of the moment of inertia, the natural frequency of the first lateral mode or the suggested design is subsequently increased over the existing one.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.04a
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• pp.154-157
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• 2000

Distributed piezoelectric sensor and actuator system has been designed for the active vibration control of shell structure. PVDF is used for the materials of sensor/actuator. To prevent the adverse effect of spillover, distributed modal sensor/actuator system is established. Although shell structure is three-dimensional structure, the PVDF sensor/actuator system can be treated as two-dimensional Finite element programs are developed to consider curved structures having PVDF modal sensor/actuator. The nine-node Mindlin shell element with five nodal degree of freedoms is used for finite element discretization. The electrode patterns and lamination angle of PVDF sensor/actuator are optimized to design the modal sensor/actuator system Genetic algorithm is used for optimization. Sensor is designed to minimize the observation spillover, and actuator is designed to minimize the system energy of the control modes under a given initial condition. Modal sensor/actuator for the first and second modes of singly curved cantilevered shell structure are designed using mentioned methods. Discrete LQG method is used as a control law. Experimental demonstrations of the active vibration control with designed sensor/actuator system have been performed successfully.

• Transactions of the Society of Information Storage Systems
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• v.7 no.2
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• pp.80-84
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• 2011

In this paper, we propose the integrated design method that enables multi-physics modeling and coupled-field analysis by connecting an electromagnetic field and a structural field. We design the 3-axis moving magnet type actuator that has the high structural stiffness and the effective electromagnetic circuit generating large electromagnetic force. Through design of experiments (DOE) and optimization, the designed actuator is optimized and satisfies high dynamic characteristics over the desired specifications.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.559-564
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• 2001

The design of an automobile mirror actuator system needs a systematic optimization due to several variables, constraints, geometric limitations, moving angle, and so on. Therefore, this article provides the procedure of a genetic algorithm(GA) based optimization with finite element analysis for design of a mirror actuator considering design constraints, geometric limitations, moving angle. Local optimum problem in optimization design with sensitivity analysis is overcome by using zero-order overall searching method which is new optimization design method using a genetic algorithm.

• Transactions of The Korea Fluid Power Systems Society
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• v.8 no.1
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• pp.1-9
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• 2011

The main design factors which effect on operating speed of linear actuator for valve operation are mass of plunger, electromagnetic motive force, inductance, and return spring, and these factors are not independent but related with each other in view point of design and electromagnetic theory. It is impossible to increase the operating speed by only change the value of any one design factor. The change of any one value results in change of any value related it in various design factors. This paper presents a speed increasing method of linear actuator using a solenoid design method by some governing equations which are composed of electromagnetic theory and empirical knowledge and permanent magnets as assistant material, and proved the propriety by experiments.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.786-790
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• 2001

In this paper, we propose an optimum design method for optical pick-up actuators. Using this method, we can design an optimal pick-up actuator having the required tracking/focusing performances. Also, the designed actuator has the small mass, force constant for small size of magnetic circuit and large resistance for reduction of heat generation. Simulation results show that this method can be potentially implemented in all the pick-up actuators.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.12
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• pp.1843-1848
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• 2010

This paper presents an analysis of the design hypothesis of integration of parts from the viewpoint of axiomatic design. In parts integration, parts with the same functions are integrated into a single part. For the analysis, a motor actuator of an outside rear-view mirror with the type of an uncoupled design was used. The parts within the actuator are checked for determining the possibility of integration, by adopting the design hypothesis of integration of parts. The design hypothesis of integration of parts is based on a type of coupled design. However, the type of incomplete coupled design that resembles the type of an uncoupled design would be better than the type of a coupled design.

• Transactions of the Society of Information Storage Systems
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• v.2 no.3
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• pp.208-213
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• 2006

The present state of the design of swing arm actuators for optical disc drives is to obtain the high efficient dynamic characteristics within a very compact volume. As a necessary consequence, the need of the small form factor (SFF) storage device has been arisen as major interests in the information storage technology. In this paper, we suggest the miniaturized swing arm type actuator that has high efficient dynamic characteristics for SFF optical disk drive (ODD). For the operating mechanism, it uses a tracking electromagnetic (EM) circuit for a focusing motion together. Moreover, due to the size constraint, the thermal stability of optical head is important. Therefore, the actuator is designed to emit the heat, which is generated by optical pick-up, along the actuator body easily. Initial model is designed based on the topology optimization method considering the thermal conductivity. Then, the structural parts of the actuator are modified to maintain the high sensitivity and to have wide control bandwidth by the design of experiments method (DOE) and new concept of decreasing mass and inertia. Finally, a swing arm type actuator for SFF ODD is suggested and its dynamic characteristics are verified.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.911-914
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• 2003

As high-capacity disk drives pow in track density, the allowable level of PES is becoming smaller. In this paper, some design concept of actuator is introduced to suppress the Butterfly mode that imposes the fundamental limitation on servo bandwidth. The effect of dynamics of proposed actuator on PES is examined by simulation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1033-1036
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• 2007

The optical disc drive has used a high NA objective lens and a shorter wavelength laser diode for high recording density. But high NA and shorter wavelength cause several margins to become short. Focusing and tracking servo has to be more accurate and active tilt compensation mechanism is also needed for coma aberration compensation. In this paper, we proposed 3-axis moving magnet type actuator. For 3-DOF motion, moving coil actuator has to equip 6 wires for supplying 3 independent signals. However, moving magnet type actuator doesn't need to change the configuration of wires because coils are in stator. So, we added tilting mechanism to 2-axis moving magnet actuator which is designed in previous research. Addition of the tilting mechanism cuts down the focusing sensitivity. So, maximization the tilting sensitivity and securing the focusing sensitivity are objectivities of this research. DOE (design of experiments) procedures of electromagnetic circuit are performed for parameter study and the optimization is also performed to maximize the tilt sensitivity. And then the final design is suggested and its performance is verified by FE simulation.