• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.348-353
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• 1994

Magnetic Servo Levitation (MSL) has been proposed as a method to drive a fast-tool servo system. This paper discusses some fundamental control and modeling issues in the development of a long-range high-bandwidth fast-tool servo based on MSL. A resursive linear model is developed to describe the system's dynamics linear model is developed to describe the system's dynamics, and further used to discuss controller design. For a given controller architecture, the performance of two controllers is then compared, one based on an approximation to the inverse plant dynamics, the second based on a adaptive neural network.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.2
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• pp.203-212
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• 2002

Active magnetic hearings allow much high surface speed than conventional ball bearings and therefore greatly suitable for high speed cutting. This paper describes a design and test of an active magnetic bearing system with 16-pole radial magnets. The spindle is originally designed for a CNC lathe and driven by outer motor with 5.5 kW power and maximum speed 10,000 rpm. Considering static load condition and geometric restrictions, radial magnet is designed 16-pole type for smaller outer diameter of the spindle system. Dynamic system characteristics such as natural frequency, critical speed, stiffness, damping and system stabilities are simulated with a rigid rotor model including direct feedback controller. The designed spindle system is realized with digital PIDD controller to compensate phase lag of PWM amplifier and magnet coils. With levitation and step response experiment the control system characteristics are tested, and the spindle is rotated up to 10,000 rpm stab1y.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2199-2202
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• 2002

In this paper, a rail-vibration controller of magnetic levitation system is designed and implemented. The target plant to be controlled is electro-magnetic type which is open-loop unstable, highly non-linear and time-varying system. The designed controller is validated by some kinds of experiments.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.3
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• pp.278-285
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• 1999

This paper utilizes the method of Q-parameterization control to design a controller which solves the problem of imbalance in magnetic bearing systems. There are two methods to solve this problem using feedback controal. The first method is to compensate for the imbalance forces by generating opposing forces on the bearing surface (imbalance compensation). The second method is to make the rotor rotate around its axis of inertia (automatic balancing);in this case no imbalance forces will be generated. In this paper we deal with only imbalance compensation. The free parameter of the Q-parameterization controller is chosen such that these goals are achieved. After the introduction of a model of the magnetic bearing system, we explain the Q-parameterization controller design of the magnetic bearing system with emphasis on the rejection of sinusoidal disturbance for imbalance compensation design. The design objectives are formulated as a linear equations in the controller free paramete Q. Finally, simulation and experimental results are presented and showed the robustness and effectiveness of the proposed controllers.

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.293-297
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• 2000

Multiseeding with (100)/(100) grain junctions of top-seeded melt growth (TSMG) processed YBCO superconductors was studied. The effect of the number of seeds and the distance between two seeds on the levitation forces and the trapped magnetic fields of the TSMG-processed YBCO samples was investigated. Multiple seeding shortened the processing time for the fabrication of TSMC-processed YBCO superconductors. The large magnetic field was trapped at the grain junction when two seeds was placed without spacing, while the amount of the magnetic field decreased when the seed distance increased. This is attributed to the increased amount of the residual melt phases around the grain junctions.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.101-102
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• 2011

The attraction force is an important parameter for permanent-magnet(PM) linear machines. This paper aims to analysis lumped magnetic circuit model of a magnetic levitation system. It accounts for the fringing effect and leakage flux which may greatly affect the accuracy of the analytical model for the optimal lumped magnetic circuit model. consequentially it will be able to apply to prospective permanent-magnet(PM) linear machines for accurate analysis.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2576-2578
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• 2005

In this paper, we address two position control scheme; the lead-lag control and the sliding mode control for a stage system, which is levitated and driven by electric magnetic actuators. This consists of a levitating object (called platen) with 4 permanent magnetic linear synchronous motors in parallel. Each motor generates vertical force for suspension against gravity and propulsion force horizontally as well. The sliding mode control algorithm is more effective than the lead-lag control algorithm to reduce effects from movements and disturbances of other axis.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.735-740
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• 2001

With the development of micro-technology, the demand for micro actuator is increasing. But, it is difficult to achieve high resolution and long travel range simultaneously with the conventional actuators. So, the noncontact surface actuator was proposed. This actuator can realize high dynamic range and the planar motion without complex cross-axis linear slides. This paper describes a magnetically suspended linear actuator for developing a non-contact surface actuator. The operating principle and the structure of the proposed linear actuator are similar to switched reluctance motor, but the proposed linear actuator utilizes normal force and propulsion force simultaneously. With this characteristic, the system can be simpler than other non-contact surface actuator.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.10a
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• pp.332-333
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• 2010

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.396-399
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• 1994

In a large class of industrial robot manipulators, its end effector for supporting the moving object have designed with mechanical suspension method(gripper). In this paper, We describe a high performance magnetically levitated end effector of robot, where is no mechanical contact and friction.