• Journal of the Korean Society for Precision Engineering
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• v.19 no.1
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• pp.143-149
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• 2002

Robot are necessary to automate the work on a vertical plane of work piece to produce a large structure like a ship, so that a permanent magnet wheel has been attempted to be used for a mobile robot. Its adhesive power was enhanced by restricting the occurrence direction of magnetic flow. Furthermore a method which weakened the adhesive force was developed for easy detachement of the wheel by changing magnetic flow with metal pin. To measure the characteristics of the adhesive and detaching farces, a load call and a gaussmeter were used. The result showed that the adhesive power was reduced to 1/3 of normal state by using 4 inducing pins.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.3
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• pp.251-256
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• 2011

Instead of multi-phase ac current, the magnetic field travels spatially through mechanical rotation of permanent magnets at the electrodynamic wheel (EDW). Traveling of magnetic field generally leads to a generation of inductive force in the traveling direction. In this paper, we suggest a spiral EDW to travel the magnetic field in the axial direction of the conductive rod. So, it is possible to levitate and transfer the rod through multi-axial forces by the spiral EDW. However, physical dimensions of permanent magnets constituting EDW influence relative ratios between three-axial forces generated on the rod. Therefore, the sensitivity analysis for design parameters is performed using FEM analysis. The stable operation is verified experimentally.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.7
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• pp.109-116
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• 2010

The magnet wheel which generates on its interfacing conductive part a repulsive force and a traction torque by rotation of permanent magnets is used to manipulate the conductive plate without mechanical contact. Here, the air-gap magnetic field of the magnet wheel is shielded partially to convert the traction torque into a linear thrust force. Although a magnitude of the thrust force is constant under the fixed open region, we can change the direction of force by varying a position of the shield sheet. So, the spatial position of conductive plate is controlled by not the force magnitude from each magnet wheel but the open position of shield sheet. This paper discusses non-contact conveyance system of the conductive plate using electromagnetic forces from multiple magnet wheels.

• Journal of Magnetics
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• v.2 no.1
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• pp.1-6
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• 1997

The magnetic and magnetostrictive properties of melt-spun ribbons of the alloys (R0.33Fe0.67)1-xBx (R=Tb0.3Dy0.7 and 0$\leq$x$\leq$0.06) are ivestigated as a function of wheel speed during melt-quenching. The saturation magnetiation of the alloys with a crystalline phase ranges from 70 to 80 emu/g and does not vary substantially with the B content. The saturation magnetization of an amorphous phase, which is formed at the condition of thigh wheel speed and high B content, is reduced significantly, however. The coercive force is minimum at x= 0.02 and increases monotonously with the further increase of B content when the microstructure mainly consists of a crystalline phase, but again it is reduced significantly by the formation of an amorphous phase. The low field sensitivity of magnetostriction with magnetic field is found to be good for the alloys with x$\leq$0.04 over a wide range of wheel speed. This magnetostrictive behavior is in contrast with that observed previously for Dy-Fe and Tb-Fe based alloys and is thought to be due to low intrinsic magnetocrystalline anisotropy of the compound.

• Journal of Magnetics
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• v.15 no.3
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• pp.128-131
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• 2010

In this paper, we propose a new design of the permanent magnet reluctance wheel which will make it possible to attach the robot to a vertical plane and move it. In the newly suggested design, a permanent magnet is utilized to enhance the adhesive force during attachment, and an electromagnet is produced to weaken the magnetic field of the permanent magnet and reduce the adhesive force for easier detachment of wheels from steel plates. To characterize the performance of this new wheel design, a 3-D finite element analysis is executed using a commercial FE program. The results show that the adhesive force is reduced effectively by the electromagnet which flows in the reverse direction of the magnetic loop of the permanent magnet when the current is supplied to the coil.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.11
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• pp.1353-1356
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• 2009

As a method obtaining linear thrust force for the magnet wheel producing a strong traction torque, the concept of magnetic shield is suggested and compared with the existing approaches. Specially, as the magnet wheel, in which the permanent magnets rotate mechanically instead of ac driving to make traveling field, is physically similar with the rotary induction motor, there is a periodical force ripple in tangential direction as well as normal direction. But, the force ripple can be suppressed from a shape change of the shield plate. Namely, the change brings out a change of entry and exit effect of the circumferential field for the magnet wheel. The feasibility of the shield concept is verified from simulation and experiment.

• Bulletin of the Korean Space Science Society
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• 2003.10a
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• pp.63-63
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• 2003

There are many actuators and sensors used for attitude control system for KOMPSAT such as Reaction Wheel Assembly, Magnetic Torque Assembly, Dual Thruster Module, Solar array Drive, Three Axis Magnetometer, Conical Earth Sensor, Fine Sun Sensor Assembly, Coarse Sun Sensor Assembly, Gyro Reference Assembly and so on. For KOMPSA T satellite it has been considered using the Magnetic Torquer (MTQ) generating the magnetic dipole moment. In general, the magnetic dipole moment for satellite attitude control system is used for dumping out the excessive reaction wheel momentum so that the reaction wheel speed is not saturated. The objective of this study is to analyze the magnetic field characteristics generated by the Magnetic Torquer using the Maxwell 2D Field Simulator software. Currently, the developing model (DM) of the MTQ is being developed and manufactured at a company under the supervision of KARL MTQ is an electromagnet consisting of a ferromagnetic cylindrical core on which an excitation coil is wound. A current is passed through the coil to produce a dipole momentum in the ferromagnetic core. The configuration of the MTQ will be introduced in the presentation. The 2 dimensional model of the MTQ is drawn as axisymmetric models in RZ plane, and each corresponding material is assigned to the each MTQ object, the core, coil, and background. After the boundary conditions, current sources, and solution parameters are set up, the magnetic field intensities, directions, and other values specified by users can be calculated by using the finite element analysis. The theoretical magnetic field quantities obtained by the Maxwell 2D Simulator can be used for the basis of the development of the MTQ.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.6
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• pp.1010-1017
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• 2013

Two-axial electrodynamic forces generated on a conductive plate by a partially shielded magnet wheel are strongly coupled through the rotational speed of the wheel. To control the spatial position of the plate using magnet wheels, the forces should be handled independently. Thus, three methods are proposed in this paper. First, considering that a relative ratio between two forces is independent of the length of the air-gap from the top of the wheel, it is possible to indirectly control the in-plane position of the plate using only the normal forces. In doing so, the control inputs for in-plane motion are converted into the target positions for out-of-plane motion. Second, the tangential direction of the open area of the shield plate and the rotational speed of the wheel become the new control variables. Third, the absolute magnitude of the open area is varied, instead of rotating the open area. The forces are determined simply by using a linear controller, and the relative ratio between the forces creates a unique wheel speed. The above methods were verified experimentally.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.635-638
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• 2000

It is necessary to work on a vertical plane of workpiece in order to produce a large structure like a ship. These works can be automated by using the robot with permanent magnet wheels. We developed the permanent magnet wheel which can be used by a mobile robot and easily detached. We enhanced an adhesive power by restricting the occurrence direction of magnetic flow. And we also developed a method which weakens adhesive magnetic force by changing magnetic flow with metal pins. We used the load cell and the gaussmeter to measure the characteristics of the adhesive force and magnetic force. We obtained the result that the adhesive power is reduced to 1/3 of normal state by using 4 inducing pins.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.310-316
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• 2016

We propose a novel contact-free transportation system in which an axial electrodynamic wheel is applied as an actuator. When the electrodynamic wheel is partially overlapped by a fixed conductive plate and rotates over it, three-axis magnetic forces are generated on the wheel. Among these forces, those in the gravitational direction and the lateral direction are inherently stable. Therefore, only the force in the longitudinal direction needs to be controlled to guarantee spatial stability of the wheel. The electrodynamic wheel consists of permanent magnets that are repeated and polarized periodically along the circumferential direction. The basic geometric configuration and the pole number of the wheel influence the stability margin of a transportation system, which would include several wheels. The overlap region between the wheel and the conductive plate is a dominant factor affecting the stiffness in the lateral direction. Therefore, sensitivity analysis for the major parameters of the wheel mechanism was performed using a finite element tool. The system was manufactured based on the obtained design values, and the passive stability of a moving object with the wheels was verified experimentally.