• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.754-758
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• 2000

In recent years, the LDM(Linear DC Motor) is widely used, because it has more merits than other rotary motors. First, if system requires linear motion, LDM realizes direct linear motion as rotary motor does not. Second, system is simple and easy to control, and so on. In optical disc drive, a tracking system consists of two parts. One is fine actuating and the other is coarse actuating. For coarse actuating VCM(Voice Coil Motor) actuator is used as a basic drive mechanism. In this paper, MC(Moving Coil) type LDM is designed, manufactured and controlled. System is composed of mechanical-electromagnetic component, therefore mechanical loss and electromagnetic loss exist. The dominent mechanical loss is friction which results from sliding between guide shaft and hole. Therefore, this paper shows the friction compensation control. High speed and accurate position is not gained only PID control, therefore other control method is applied to the system.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.6
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• pp.62-69
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• 2002

For improving the motion accuracy of hydrostatic table, corrective machining algorithm is proposed in this paper. The algorithm consists of three main processes. reverse analysis is performed firstly to estimate rail profile from measured linear and angular motion error, in the algorithm. For the next step, corrective machining information is decided as referring to the estimating rail profile. Finally, motion errors on correctively machined rail are analized by using motion error analysis method proposed in the previous paper. These processes can be iterated until the analized motion errors are satisfied with target accuracy. In order to verify the validity of the algorithm theoretically, motion errors by the estimated rail, after corrective machining, are compared with motion errors by true rail assumed as the measured value. Estimated motion errors show good agreement with assumed values, and it is confirmed that the algorithm is effective to acquire the corrective machining information to improve the accuracy of hydrostatic table.

• 연구논문집
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• s.34
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• pp.101-112
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• 2004

In order to analyze the motion errors of the aerostatic stage, it is necessary to consider the influence of the moment variation occurredinside the pads. In this paper, a motion error anaysis method utilizing the transfer functions on the reaction force and moment is proposed, and general characteristics of the transfer functions are discussed. Calculated motion errors by the proposed method show good agreement with the ones calculated by Multi Pad Method, which is considered the entire table as an analysis object. Also, by the introduction of the transfer function of motion errors, which represent the relationship between the spatial frequency components of the rail form error and motion errors, motional characteristics of the porous aerostatic stage can be generalized. In detail, the influence of the spatial frequencies is analyzed quantatively, and the patterns of the insensitive frequencies which almost do not affect the linear motion error or angular motion error according to the rail length ratio and the number of the pad are verified. The relationship between the moment variation occurred inside the pads and the motion errors is also verified together.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.7
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• pp.185-194
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• 2004

In order to analyze the motion errors of the aerostatic stage, it is necessary to consider the influence of the moment variation occurred inside the pads. In this paper, a motion error analysis method utilizing the transfer functions on the reaction force and moment is proposed, and general characteristics of the transfer functions are discussed. Calculated motion errors by the proposed method show good agreement with the ones calculated by Multi fad Method, which is considered the entire table as an analysis object. Also, by the introduction of the transfer function of motion errors, which represent the relationship between the spatial frequency components of the rail form error and motion errors, motional characteristics of the porous aerostatic stage can be generalized. In detail, the influence of the spatial frequencies is analyzed qualitatively, and the patterns of the insensitive frequencies which almost do not affect the linear motion error or angular motion error according to the rail length ratio and the number of the pad are verified. The relationship between the moment variation occurred inside the pads and the motion errors is also verified together.

• Proceedings of the Korean Society of Rheology Conference
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• 2000.11a
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• pp.1-1
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• 2000

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.347-353
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• 2004

Due to various advantages over the conventional linear motion device such as ball-screw, linear motors have been used in wide variety of industrial applications for years. Driven by increased demand for precision machine tools, the importance of high positioning accuracy, high stiffness and high thrust are greatly increasing. The merits of linear motor are high speed high acceleration and good positioning accuracy. In addiction, Linear motor for high qualify machine tool call for high thrust, high stiffness. In this paper, thrust ripple, detent force and thermal behavior are considered for the development of high performance linear motor whose thrust is up to 1,900N. This paper presents a comprehensive study for an iron core type linear motor characteristics that include the influence of PM position on thrust ripple by detent force and motor dynamics as well.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.584-587
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• 1992

Because linear motor directly drives linear motion, it does not need conversion equipment such as belt and gear. Especially linear pulse motor provide more precise positioning and large force of linear pulse motors. As current manufacture technic of linear pulse motor is much to be desired at home. This motor lay out to make use of computer aided design program, In this paper the experimental motor is 2-phases 4-poles hybrid pulse motor which has teeth per pole Simulation program is divided its function into 4 parts - air gap permeance analysis, permanent magnet & non-linear core operating point determine, winding configuration, leakage flux analysis. It is possible to make motor static and magnetic characteristics for this simulation program. Also, by varying input parameters of the program, experimental motor is to be compared to motor characteristics.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.3
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• pp.134-138
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• 2005

A typical conventional systems of a linear motion use rack and pinions or ball screws to convert rotary motions from DC servo motors. A linear motor has been used a several field for a MEMS technology and a aircraft carrier. We have studied a transient response of a linear actuator with a damping ratio, spring constant and a pressed power for a constant stroke control.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.785-790
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• 2001

Linear motors can drive a linear motion without intermediate gears, screws or crank shafts. Linear motors can successfully replace ball lead screw in machine tools, because they have a high velocity, acceleration and good positioning accuracy. On the other hand, linear motors emit large amounts of heat and have low efficiency. In this paper, heat sources of a synchronous linear motor with high velocity and force are measured and analyzed. To improve the thermal stiffness of the linear motor, an insulation layer with low thermal conductivity is inserted between cooler and machine table. Some effects of the insulation layer are presented.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.3
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• pp.123-130
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• 2002

Linear motors can drive a linear motion without intermediate gears, screws or crank shafts. Linear motors can successfully replace ball lead screw in machine tools because they have a high velocity, acceleration and good positioning accuracy. On the other hand, linear motors emit large amounts of heat and have low efficiency. In this paper, heat sources of a synchronous linear motor with high velocity and force measured and analyzed. To improve the thermal characteristics of the linear motor, an insulation layer with low thermal conductivity is inserted between cooler and machine table. Some effects of the insulation layer are presented.