• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.3-6
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• 1998

In this paper, we evaluated the effect the tooth shape influenced against the thrust force which then was confirmed by experimentation. We analyzed the effect of by measuring static thrust force of the Phases of A and B. With this result, we found that there is an area where the thrust force abruptly decreases because the variance of the airgap permeance is very small following the positions of the stator and the mover. And the unbalance among phases showed almost equal, which means that static thrust force of the phases of A and B is very small because magnetic path of the 2-phase 8-pole HB-type is almost equal.

• Journal of Welding and Joining
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• v.19 no.4
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• pp.399-405
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• 2001

A dynamic force balance model is proposed in this work as an extension of the previous static force balance model to predict metal transfer in arc welding. Dynamics of a pendant drop is modeled as the second order system, which consists of the mass, spring and damper. The spring constant of a spherical drop at equilibrium is derived in the closed-form equation, and the inertia force caused by drop vibration is included in the drop detaching condition. While the inertia force is small in the low current range, it becomes larger than the gravitational force with current increase. The inertia force reaches half of the electromagnetic force at transition current, and has considerable effects on drop detachment. The proposed dynamic force balance model predicts the detaching drop size more accurately than the static force balance model.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.3
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• pp.131-137
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• 2000

2 phase 8 pole HB-type(flat-type) Linear Pulse Motor can be used as the high precision position actuator because of its many advantages (simple control circuit, high stiffness characteristics, etc). Also, using the microstep drive, its noise and vibration can be reduced considerably and positional resolution may be increased further. But, $20^{\circ}$tapered tooth shape to reduce the normal force have an much effect on the static thrust force characteristics. And, because of hybrid-type LPM, interaction between the permanent magnet and the excitation current have an effect on the various characteristics of LPM. Hence, in this paper, the effect of tooth shape on static thrust force characteristics was analyzed using the air gap permeance by finite element method. For analyzing the effect of unbalance between the m.m.f of permanent magnet and the m.m.f of excitation current, unbalanced m.m.f coefficient $\sigma$ were introduced with the permenace matrix and switching matrix.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.1088-1094
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• 1997

An indirect cutting torque and cutting force estimation method is presented. This method uses a time-domain model between the spindle motor power, which calculated form measured spindle motor current and voltage. Spindle motor power is linear with cutting torque in this model. The cutting force is proportional to the cutting torque. Using trial cut, parameters are determined. Static sensitivity is suitable for various cutting conditions. The presented method is verified under several cutting tests on the CNC horizontal machining center.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.18-21
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• 1996

This paper deals with experimentation on static test of linear induction motor for the propulsion system of UTM(Urban Transit Maglev). It is very important that vertical force zero effects to levitation field of maglev. Because it is continuous for air gap 11mm of levitated maglev vehicle. Then we found the slip frequency that the vertical force zero due to it is variable. Thus we had compared between simulation value and experiment value for lim by static test Jig.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.1
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• pp.40-46
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• 2007

High speed machining has become the main issue of metal cutting. Due to increase of the rotational speed of the spindle, problems such as the run-out errors and reduced stiffness must be overcome to improve the machining accuracy. In order to solve the problems, it is important to determine the appropriate clamping unit and tooling system. This paper presents an investigation into an analysis of static stiffness in the main spindle interface. Finite element analysis is performed by using a commercial code ANSYS according to variation of cutting force, clamping force and rotational speed. From the finite element results, it is shown that the rotational speed and clamping force mostly influence on the variation of the static stiffness in the main spindle interface.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.1
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• pp.106-113
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• 2004

Most of mechanical structures are composed of many substructures connected to one another by various types of mechanical joints. In automotive engineering, it is important to study these connected structures under various dynamic forces for the evaluations of fatigue life and stress concentration exactly. In this study, the dynamic response of vehicle structure to external forces is classified an inverse problem involving strains from the experiment and the analysis. The practical dynamic forces are determined by the combination of the analytical and experimental method with analyzed strain by quasi-static finite element analysis under unit force and with measured strain by a strain gage under driving load, respectively. In a stressed body, inter-molecular chemical bonds are failed beyond the certain magnitude. The failure of molecular structure in material is considered as a time process of which rate is determined by mechanical stress. That is, the failure of inter-molecular chemical bonds is the fatigue lift of material. This kinetic concept is expressed as lethargy coefficient. And S-N curve is obtained with the lethargy coefficient from quasi-static tensile test. Equivalent practical dynamic force is obtained from the identification of practical dynamic force for one loading point. Using the practical dynamic force and S-N curve, fatigue life of a window pillar is analyzed with FEM under the identified force by the procedure of above mentioned.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.3
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• pp.83-91
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• 2000

During static walking of a quadruped walking robot, stability of the robot depends on whether the projection of the mass center is located within the supporting area that is varying with leg motion and formed by standing legs. In this paper, force margin instead of the mass center was used to determine stability and body-tilting method was used to enhance it. On-line control of body tilting was realized with simple reaction feedback based on force margin of the static walking model of the robot instead of complicated calculation. Model reference on-line control where the model searches stable pose for predefined force margin also gave good walking performance.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.1
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• pp.157-162
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• 2000

The ball bearings are the widely-used machine elements in many machineries. They support not only the radial and the axial force but also the moment in many cases. To simply determine the limit load which can be maintained on an ball bearing or survived in wanted life, the combined the radial and axial force with the moment is converted to the equivalent radial or axial load. However, it is not easy to calculate the equivalent load on the ball bearings. So the simplified equations to evaluate the dynamic and static equivalent load considering the axial force and moment are proposed in this analysis. And the modified equation for the static equivalent radial load with the moment and the axial load is proposed. It is desired that these equations are effectively refered in designing the machineries where the ball bearings are installed.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.549-554
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• 2008

The recent trains are almost being operated by the mechanical propulsion force to drive the gear and wheel with the traction motor. However Magnetic Levitation Vehicle is differently operated. Magnetic Levitation Vehicle is applied with Linear Induction Motor(LIM) that has many advantage like to high capability of going up to slope, low noise, easy to control of speed. So domestic and many advanced countries are interested in Magnetic Levitation Vehicle and they have been studying about it continuously. Thus this paper is studied the LIM test method of static states and guess the optimum driving point by characteristic of static states for LIM. The test items are measurement of thrust force by changed air gap, measurement of thrust force and normal force by changed slip frequency etc.