• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2003.12a
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• pp.177-181
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• 2003

This paper presents a 3-axis fine positioning stage. All the procedure concerning the design and fabrication of the stage are described. The stage considered here is composed of flexure hinges, piezoelectric actuators and their peripherals. A special flexure hinge is adopted to be able to actuate the single stage in three axes at the same time. A ball contact mechanism is introduced into the piezoelectric actuator to avoid the cross talk among the axes. The final design is obtained with the theoretical analysis on the stage. An actual fine stage is developed and the design specifications are verified through an experiment.

• Journal of KSNVE
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• v.8 no.4
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• pp.643-653
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• 1998

The sub-resonance modes can be easily excited by the assembling tolerance in the asymmetric type optical pick-up actuators, compared with the symmetric type. In this paper, we propose the novel method for reducing the vibration due to the sub-resonance modes whose amplitude can be decreased by adding the damper and increasing the flexibility of holder PCB. Using the finite element method, the change of mode shapes is investigated as the shape of holder PCB is modified. Experimental results support that the propopsed method reduces remarkably the vibration of sub-resonance modes of the optical pick-up actuator.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.648-651
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• 2003

This paper presents a 3-axis fine positioning stage. All the procedure concerning the design and fabrication of the stae are described. The stage considered here is composed of flexure hinges, piezoelectric actuators and their peripherals. A special flexure hinge is adopted to be able to actuate the single stage in three axes at the same time. A ball contact mechanism is introduced into the piezoelectric actuator to avoid the cross talk among the axes. The final design is obtained with the theoretical analysis on the stage. An actual fine stage is developed and the design specifications are verified through an experiment.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.3
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• pp.147-154
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• 2004

This paper presents a procedure for analysis and design of a fine positioning stage, which has many applications in industries for machine tools, semiconductor, LCD and so forth. The stage considered here is based on a single module with 3 axes which is composed of flexures hinges, piezoelectric actuators and their peripherals. Through a series of analysis, the structural analysis model is simplified as a rigid body(the moving part) and springs(the flexures hinges). An experimental design procedure is applied to determine the dimension of flexures hinges. A sensitivity analysis on the notch positions is also performed to obtain a guideline of fabrication accuracy for the stage. An actual fine stage is made and verified through an experiment on the dynamic characteristics.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.555-556
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.875-876
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• 2009

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.5
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• pp.361-368
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• 2015

This paper deals with a robust fine seek controller design problem with multiple constraints using a genetic algorithm. A robust $H\infty$ constraint is introduced to attenuate effectively velocity disturbance caused by the eccentric rotation of the disk. A weighting function is optimally selected based on the estimation of velocity disturbance and the estimated minimum velocity loop gain. A robust velocity loop constraint is considered to minimize the variances of the velocity loop gain and bandwidth against the uncertainties of fine actuator. Finally, a robust fine seek controller is obtained by solving a genetic algorithm with an LMI condition and an appropriate objective function. The proposed controller design method is applied to the fine seek control system of a DVD recording device and is evaluated through the experimental results.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.7
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• pp.640-646
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• 2007

Actuator-induced disturbance is one of the crucial factors of spacecraft attitude pointing and stability in fine attitude control problems. The control moment gyros (CMGs) are known as very attractive actuators from the point of high power and low weight. In order to develop a CMG as an actuator for fine controls, CMG-induced disturbances should be analyzed. Therefore, this paper aims to develop an analytic model and predict the effect of disturbances of CMGs by assuming static and dynamic imbalances. The proposed model is induced by the Lagrangian method on the basis of the small signal assumption.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.665-666
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• 2006

In precision laser microfabrication, focusing is essential to acquire good machining precision and uniform machining quality. If it does not perform, laser machining cannot be realized. So, confocal scanning method with high depth resolution is used for focus detection technique. This paper is concerned with a procedure for design, analysis and performance test of an autofocus fine actuating stage, which is composed of flexure-hinge type lever mechanism and piezoelectric actuator. Through series of analytical design, the stage is simplified as a rigid bodies(lever and main body) and springs(flexure hinges). The simplified model was applied to determine the dimension of flexure hinges and lever. After structural analysis confirmed design requirement, an actual stage was made and verified through an experiment on the static and dynamic characteristics(maximum stroke and 1st natural frequency). The fabricated stage was satisfied with the design requirement.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.180-185
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• 2009

Actuator-induced disturbance is one of the crucial factors of spacecraft attitude pointing and stability in fine attitude control problems. The control moment gyros (CMGs) are known as very attractive actuators from the point of high power and low weight. In order to develop a CMG as an actuator for fine controls, CMG-induced disturbances should be analyzed. Therefore, this paper aims to develop an analytic model and predict the effect of disturbances of CMGs by assuming static and dynamic imbalances. The proposed model is induced by the Lagrangian method on the basis of the small signal assumption. In this research, mechanical system of the CMG is designed and the main components of CMG are producted.