• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.423-428
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• 2002

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 accurcy. In addition, Linear motor for high quality 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 4,000N. This paper presents a comprehensive study for an iron core type linear motor characteristics that include the influence of PM position on thrust, thrust ripple by detent force and motor dynamics as well.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.291-296
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• 2000

Liner DC motors are widely used for servo-actuator, which would be applied for semiconductor equipments and precise machining systems. we have been developed linear DC motor with high speed, acceleration and position accuracy. From performance test, the position accuracy. From performance test, the position and repeatability accuracy were able to be controlled with 10 ${\mu}{\textrm}{m}$ and $\pm$1 ${\mu}{\textrm}{m}$, respectively. The highest acceleration and speed were obtained 3 G and 2m/sec, respectively. Static thrust force was 270N, and then error was 25%.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2399-2401
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• 2001

This Paper presents a positioning control method of the LBLDCM(Linear Brushless DC Motor) under friction. The friction may cause steady state position error. So it is necessary to consider friction effect for precision positioning control. The proposed control method uses disturbance observer algorithm and friction compensation. The experimental results of the proposed control method based on the disturbance observer are presented to show its effectiveness.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.33-36
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• 1997

The merits of linear motor are high speed, high acceleration and goad positioning accuracy. In addition, Linear motor for high quality machme tool call for high thrust, high stiffness. In using linear motor we also consider thrust ripple, detent force and thermal behavior. In this research, Iron core type single sided linear DC motor(LDM) is designed which thrust is 6,000 N. To accomplish this design, Various research is hlfilled l~ke the relation of thrust and permanent magnet position angle, the variation of detent force and thrust ripple, dynamic characteristics, and so on.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.343-346
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• 2003

In order to discuss the availability of the hydrostatic guideway driven by the coreless linear motor to ultra precision machine tools, a prototype of guideway is designed and tested in this research. A coreless linear DC motor with the continuous force of 156 N and a laser scale with the resulution of 10 nm are used as the feeding system. The experiments are performed on the static stiffness. motion accuracy, positioning accuracy. microstep response and variation of velocity. The guideway has the infinite axial stiffness within 50 N of applied load, and has 0.08 ${\mu}{\textrm}{m}$ of linear motion error and 0.1 arcsec of angular motion error. It also has 0.21 ${\mu}{\textrm}{m}$ of positioning error and 0.09 ${\mu}{\textrm}{m}$ of repeatability, and it shows the stable response against the 10 nm resolution step command. The velocity variation of feeding system is less than 5%. From these results, it is confirmed that the hydrostatic guideway driven by the coreless linear motor is very useful for the ultra precision machine tools.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.1
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• pp.15-22
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• 2002

This paper introduces a compensating system for machining error, which is resulted from chucking with separated jaws. In machining the chucked cylindrical workpiece, the deterioration of machining accuracy, such as out-of-roundness is inevitable due to the variation of the radial compliance of the chuck workpiece system which is caused by the position of jaws with respect to the direction of the applied force. To compensate the chucking compliance induced error, firstly roundness profile of workpiece due to chucking compliance after machining needs to be predicted. Then using this predicted profile, the compensated tool feed trajectory can be generated. And by synchronizing the cutting tool feed system with workpiece rotation, the chucking compliance induced error can be compensated. To satisfy the condition that the cutting tool feed system must provide high speed and high position accuracy, brushless linear DC motor is used. In this study, firstly through the force-deflection experiment in workpiece chucked lathe, the variation of radial compliance of chuck workpiece system is obtained. Secondly using the mathematical equation and cutting experiment result, the predicted profile of workpiece and its compensation tool trajectory are generated. Thirdly the configuration of compensation system using linear motor is introduced, and to improve the system performance, PID controller is designed. Finally the tracking performance of system is examined by experiment. Through the real cutting experiment, roundness is significantly improved.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.6
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• pp.139-144
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• 2004

In order to discuss the availability of hydrostatic guideways driven by the coreless linear motor to ultra precision machine tools, a prototype of guideway is designed and tested in this research. A coreless linear DC motor with the continuous force of 156 N and a laser scale with the resolution of 0.01 ${\mu}{\textrm}{m}$ are used as the feeding system. The experiments are performed on the static stuffiness, motion accuracy, positioning accuracy, microstep response and variation of velocity. The guideway has the infinite axial stillness within 50 N of applied load, and by the motion error compensation method using the Active Controlled Capillary, 0.08 ${\mu}{\textrm}{m}$ of linear motion error and 0.1 arcsec of angular motion error are acquired. The guideway also has 0.21 ${\mu}{\textrm}{m}$ of positioning error and 0.09 ${\mu}{\textrm}{m}$ of repeatability, and it shows the stable response against the 0.01 ${\mu}{\textrm}{m}$ resolution step command. The velocity variation of feeding system is less than 0.6 %. From these results, it is confirmed that the hydrostatic guideway driven by the coreless linear motor is very useful fur the ultra precision machine tools.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.623-625
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• 1992

This study presents a design method for linear DC motor which substituted for rotary combined with conversion apparatus and the designed motor is analyzed. To design the linear DC motor, magnetic cicuit network method is introduced and characteristics of motor at steady state are analyzed using FEM. And the transient behavior is investigated by using the finite element analysis coupling voltage equation and dynamic equation.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.3078-3080
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• 2000

In this paper. we designed a high precision Linear DC Motor(LDM) Driver with $120^{\circ}$ commutation method. It was composed of three parts which were divided into Power and Inverter Circuit. Analog Circuit with PWM Generation and Fault Protections. and Logic Circuit. We selected PMAC Controller by Delta Tau Co. for testifying a high accuracy of a designed driver. A high precision driver enhanced a response to changes of velocity and acceleration in motion and improved the accuracy.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.1
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• pp.21-26
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• 2000

This paper describes a positioning system for ultra-precision that will be utilized in semiconductor manufacturing field and precision machinery. This system is composed with laser scale unit with 10nm resolution, ball screw with LM guide, brushless DC servo motor, vibration isolator and is equipped in chamber for continuous measuring environment. The dynamic of table, the problem of servo control and the traceability for micro step motion are described. These data will be applied for getting more stable system with 50nm resolution.