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論文

論文
福室, 允央 ; 大関, 健一郎 ; 斎藤, 正人 ; 葛, 徳梁 ; 村上, 岩範 ; 長屋, 幸助
出版情報: 日本機械学會論文集. C編.  70  pp.377-384,  2004-02-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />A simple and stable energy-storage flywheel system with high temperature superconducting levitation is presented. In order to have stable levitation, a superconductor and a permanent magnet are used, and 3 permanent magnets support the top of the shaft. In the part of drive system, 8-poles permanent magnet and 8 coils are used to cancel electromagnetic forces in the radial direction. An electromagnetic damper consisting of permanent magnet for levitation and 4 coils is presented which lies at both ends of the shaft. When the shaft vibrates in the direction perpendicular to the shaft axis, current flows in the damper coil. It generates the electromagnetic force. The force is in proportion to vibration frequencies of the shaft, so that the force behaves like damping forces. Using this system, a control like the sensorless control is performed. Experimental tests have been carried out for the system as just mentioned. It is clarified that our system has stable levitation, and vibrations are suppressed significantly. 続きを見る
2.

論文

論文
長屋, 幸助 ; 小杉, 泰裕 ; 鈴木, 孝明 ; 村上, 岩範
出版情報: 日本機械学會論文集. C編.  65  pp.1530-1537,  1999-04-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />A simple but stable non-contact high Tc superconducting levitation system with a vertical shaft has been presented. The system consists of a superconductor and permanent magnets. In the system, only a lower end of the shaft is supported by a high Tc superconductor, and the other end is supported by two ordinary permanent magnets. Since the restoring force is small with respect to the radial direction the system becomes unstable when the force act in the radial direction, so it is difficult to drive the shaft by electromagnetic forces in using such as motors. Then, a driving system using electromagnets has been presented, in which the balanced forces act on two opposite sides of the disc type rotor in the axial direction. Since the system has no unbalance force from an analytical point of view, the rotor will be able to rotate without control. In the system, however, since there is the eccentricity between the center of rotation and magnetic center, so vibrations are generated. This study also presents an optimal control method of the vibrations. To validates the proposed system, and the control method, experimental tests have been carried out. 続きを見る
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論文

論文
長屋, 幸助 ; 塚越, 正人 ; 小杉, 泰裕 ; 村上, 雅人
出版情報: 日本機械学會論文集. C編.  64  pp.2520-2527,  1998-07-25.  日本機械学会
概要: application/pdf<br />Journal Article<br />The present article discusses a modeling and control of high-T_c superconducting levitation system. The paper first clarifies analytical expressions for obtaining nonlinear levitation force given by the present author, then presents at vibration control method in which feedback currents involving frequency weights. In the method, an addition of a square of the displacement and currents in a frequency domain is taken as a cost function. Optimal coefficients of the transfer function of the controller are obtained by minimizing the cost function. Hence, the spillover instability due to the nonlinear vibration will be redriced. Numerical calculations have been carried out for some typical problems. To validate the present method, experimental tests also have been carried out. 続きを見る