• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.1173-1176
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• 1995

We design and analyze two type stators for brushless DC linear motors by the experiment and the computational analysis. For a U-shape stator, the maximum manetic flux density by the finite element method(FEM) is large than that by the experiment by 1.0~2.2%. The result by the FEM is so accurate that it can be applied to the geometric design for the optimization. To increase the maximum magnetic flux density, we suggest an improved stator and analyze it by the 3-D and 2-D models. The maximum magnetic flux density of the improved stator is large than that of the U-Shape stator by 2.7%. Considering the size of the improved stator and maximum magnetic flux density, we determine that the optimized thickness is 5mm for a given specification.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.10
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• pp.2637-2646
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• 1995

Combustion instability in solid-propellant rocket motors depends on the balance between acoustic energy gains and losses of the system. The objective of this paper is to demonstrate the capability of the program which predicts the standard longitudinal stability using acoustic modes based on linear stability analysis and T-burner test results of propellants. Commercial ANSYS 5.0A program can be used to calculate the acoustic characteristic of a rocket motor. The linear stability prediction was compared with the static firing test results of rocket motors.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1218-1223
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• 2009

LIM(Linear induction motor)s are the main type of motors used for urban Maglev vehicles because they are less expensive to operate at a lower speed than linear synchronous motors. An LIM generates an attraction force while running, which perturbs the air gap of the electromagnet. This undesirable air gap variation could result in the mechanical contact of an electromagnet with the reaction plate. For this reason, the magnitude of the air gap variation must be limited within a certain range. The air gap changes when running the 1/2 vehicle under development for testing are analyzed through a test on the test track at KIMM. The results from this study could be used to minimize the air gap variations due to attraction force from LIM.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2672-2674
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• 2000

In this paper. feedback linearization and the sliding mode control(SMC) are used together for uncertain nonlinear system. An advantage of feedback linearization technique is to make linear control theories can be used for nonlinear system and the SMC have the robustness. But the dynamics of the SMC has the dynamics lower order than that of the original system. Therefore the linear control theory can not be used with the SMC. The novel sliding surface of the SMC can have the dynamics of the nominal non linear system controlled by the feedback linearization. The proposed method can be used for the control of induction motors.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.416-423
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• 2004

This paper presents the thermal characteristic analysis of a high-speed horizontal machining center with spindle speed of 50,000rpm and feedrate of 120m/fin. The spindle system is designed based on the built-in motor, angular contact ceramic ball bearings, oil-air lubrication and oil-jacket cooling method. The X-axis and Y-axis feeding systems are composed of the linear motors and linear motion guides, and the Z-axis feeding system is composed of the servo-motor, ball screw and linear motion guides. The thermal characteristics such as the temperature distribution, temperature rise, thermal deformation and step response, are estimated based on the finite element model of machining center and the heat generation rates of heat sources related to the machine operation conditions. Especially, the thermal time constant assessed from the step response function is introduced as an index of thermal response characteristics.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.5
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• pp.30-37
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• 2004

This paper presents the thermal characteristic analysis of a high-speed horizontal machining center with spindle speed of 50,000rpm and feedrate of 120m／min. The spindle system is designed based on the built-in motor, angular contact ceramic ball bearings, oil-air lubrication and oil-jacket cooling method. The X-axis and Y-axis feeding systems are composed of the linear motors and linear motion guides, and the Z-axis feeding system is composed of the servo-motor, ball screw and linear motion guides. The thermal characteristics such as the temperature distribution, temperature rise, thermal deformation and step response, are estimated based on the finite element model of machining center and the heat generation rates of heat sources related to the machine operation conditions. Especially, the thermal time constant assessed from the step response function is introduced as an index of thermal response characteristics.

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.212.2-212.2
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• 2008

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.885-887
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• 2000

The paper proposes the characteristic analysis method to consider the saturation of teeth and poles in the hybrid stepping motors. The proposed method is based on the equivalent magnetic circuit coupling with the finite element analysis. The equivalent magnetic circuit is used to analysis the characteristics of the hybrid stepping motors. And the FE analysis is used to compute the non-linear parameters included the equivalent magnetic circuit in the hybrid stepping motors. Simulation and experiment results show that the proposed technique is compared with the classical method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1019-1020
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.259-260
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• 2006