• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.985-990
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• 1995

Recently, the development of high speed and high precision NC-lathe for piston head machining is needed for the complexity and diversity of the piston head shape used in automobile reciprocating engine. THe piston head has many complex shapes in the aspect of fuel economy, such as ovality, profile, double ovality and recess. Among them, for the maching of the over shape of 0.1~1mm the cutting tool should move periodically symchronized with the rotation of piston workpiece. The cutting tool feeed system must have high positioning accuracy for the precise machining, high speed for the fast maching and high dynamic stiffness for the cutting force. The linear brushless DC motor is used for satisfying these coditions. The ballbush guide and supporting guide using turcite is used for the guidance of the feed drive system. Linear encoder, digital servo ampllifer and controller are used for driving the motor. THis paper presents the design and simulation of the new tool feed system for noncircular machining.

• 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.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.4B no.1
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• pp.20-23
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• 2004

BLDCMs are widely used in many industries. In certain specialized areas, they need to have high efficiency, high power rate and produce a low volume of noise, etc. In this study, a new type of slotless BLDCM is proposed that has no cogging torque, low iron loss and low volume as compared to commonly used BLDCMs. With a high performance magnet and coreless compact winding structure similar to those employed in linear synchronous motors, motor volume is reduced. The proposed motor has been put been through various experiments arid has demonstrated acceptable results for industry applications.

• Journal of Magnetics
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• v.6 no.3
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• pp.101-107
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• 2001

A model to describe the effect of stator slotting in the airgap region of a linear brushless permanent magnet motor (LBLPMM) is proposed for analytical prediction of magnetic field distribution. It is a two-dimensional model based on superposition of the effect of stator slotting and main field due to permanent magnet (PM) without stator slotting. The effect of stator slotting is expressed in form of a generalized equation, which is obtained by numerical analysis and is a function of motor geometric parameters, so the proposed model effectively accounts for the effect of stator slotting in the airgap field distribution according to change of motor geometry or relative motion of stator and armature. Results of prediction from the proposed model are compared with corresponding finite element analysis.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.32-34
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• 1997

For a given brushless DC linear motor, we suggest the numerical prediction methods to analyze it's thrust characteristics. First, we calculate the magnetic flux density by the finite element method, and we then compute the maximum thrust with three computational methods - a Lorentz equation, a Maxwell stress method and a virtual work method. To confirm the accuracy of the computational methods, we measure the thrust of the linear motor made by our laboratory with a force-torque sensor. Also, we calculate the thrust by the measured back electromotive force. To choose the appropriate method for a specified application, we compare the maximum thrusts of the computational method and the calculation by the back electromotive force with the measured one. We conclude that the Maxwell stress method is turned out the best because it has the most accurate results among three computational methods and it is more convenient than the calculation method by the back electromotive force.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.1
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• pp.61-66
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• 2012

Linear motors has been developed for factory automation, transportation applications, among other applications. As the trend toward compact sizes in micro electronic products progresses, the required motor drives in these applications need to be downsized with increased power densities. It appears that the winding of miniature linear motors is the most awkward part to be scaled down from conventional motor designs when miniaturizing. This paper presents an alternative design for slotless linear motors. A novel flexible printed circuit winding has been applied to obtain a simplified but qualified result. Having explained the prototyping and inspection, a discussion is given to examine the achievement of this study.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.10-12
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• 1997

For a given brushless DC linear motor, we analyze the thrust characteristics. We measure the back-EMF and then calculate the thrust with it. To compare the thrust, we measure it direct with force-torque meter and we calculate it from Lorentz equation. As the thrust and the back-EMF vary linearly according to the current and the velocity respectively, we define the thrust constant and the back-EMF constant. To match the motor to its controller, we calculate the thrust constant and the back-EMF constant. The result calculated with the back-EMF differs from that of the measurement by only 4.4%.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.179-182
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• 1998

This paper is proposed a selection method of the major design dimension which constrain the maximum acceleration capability and minimum power loss of surface-mounted brushless do motor with NdFeB permanent magnet for servo drives. Expressions are derived from the air-gap flux density and the linear current density around the stator periphery and design dimensions. The linear current density is limited by the need to avoid demagnetization. In this paper, We compute the optimum design dimensions of 2KW BLDC motor with maximum acceleration capability and minimum power loss by using genetic algorithm.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.6
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• pp.982-990
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• 1994

In this paper, we consider feedback-kinearizing control of brushless dc motors which have been increasingly used in high-performance servo applications, We completely characterize the whole class of the feedback controllers that enable the brushless dc motors to behave like linear systems but without torque ripple. The whole class of the feedback-linearizing controllers is characterized in the explicit form which contains a function to be chosen freely. The previously known controllers correspond to either the particular ones in our whole class of the feedback-Linearzing controllers or their truncated Fourier expansions. This free function can be used to achieve other control objectives as well as linear dynamic characteristics. Furthermore, our feedback-linearizing controllers can be easily determined from the measurement data of back EMF.

• Journal of Ocean Engineering and Technology
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• v.22 no.4
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• pp.14-19
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• 2008

This paper proposes a mixed $H_2/H_{\infty}$ optimal PID controller with a genetic algorithm based on the dynamic model of a brushless direct current (BLDC) motor and applies it to speed control. In the dynamic model of the BLDC motor with perturbation, the proposed controller guarantees arobust and optimal tracking performance to the desired speed of the BLDC motor. A genetic algorithm was used to obtain parameters for the PID controller that satisfy the mixed $H_2/H_{\infty}$ constraint. To implement the proposed controller, a control system based on PIC18F4431 was developed. Numerical and experimental results are shown to prove that the performance of the proposed controller was better than that of the optimal PID controller.