• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.2
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• pp.226-235
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• 1992

This paper is concerned with the robust control of LQ state feedback regulators with poles in a specified region in the presence of system uncertainty. The robust stability results for the constant and nonlinear time varying perturbations are derived in terms of bounds of the perturbed system matrices and the weighting matrices in the performance index of LQ problem. The theoretical results are applied to the gap control problem of an attractive-type-magnetic levitation system and the effectiveness is proved by the implementation of digital control using 16 bits microcomputer.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.12-14
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• 1996

Static tests on the performance of the electromagnets of the electromagnetic maglev vehicle were conducted. Performance of the magnets wound with the alumimum sheet were tested and compared with that of the magnets constructed with aluminum coils of rectangular cross section. It turns out that with the use of the aluminum sheet we can improve the lifting force per magnet by 19.5% and thereby make electromagnets lighter than those made with the aluminum coils of rectangular cross section.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.68-70
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• 1995

The controller for magnetically suspended vehicles considering the speed characteristics is presented. Generally, the attraction force of magnet is determined by input current and air gap. However, when MAGLEV runs at high speed, induced eddy currents in the rail decrease the attraction force. Thus control characteristics of MAGLEV become deteriorated. Therefore, the variation of attraction force according to speed must be considered. Thus we analyzed the speed characteristics of the magnet by FEM. Also, we study on the control characteristics according to speeds, and design the controller considering the decline of levitation force using Neural Network.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.3
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• pp.452-460
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• 2002

The precision stage using a novel contact-free planar actuator based on magnetic farces, magnetized force and Lorentz farce, is suggested. In the promising magnetic structure, the mover is driven directly without any transmission mechanism, and doesn't need any auxiliary driver for its posture calibration. Then it is estimated that the proposed operating principle is very suitable for work requiring high accuracy and cleanness, or general-purpose nano-stage. In this paper, we discuss a driving principle of the planar system including the magnetic force generation mechanism, a framework for the force model, governing characteristics of the levitated plate, and a planar motion control of the constructed prototype. And experimental results are given to verify the derived theoretical model and a feasibility of the system.