Magnetic levitation control of high-temperature superconducting floating coils using image-data processing

针对Mini-RT项目中超导悬浮线圈的磁悬浮，提出了一种新的基于图像数据处理的反馈控制方案。在我们以前研究的传统系统中，浮置线圈的位置是使用激光传感器测量的，并且浮置线圈的电流是用模拟PID电路控制的。新系统已将数字控制程序与个人计算机（PC）结合起来。该系统采用图形化测控软件LabVIEW，并通过悬浮永磁体验证了系统的反馈控制能力。采用Bi-2223银护套高温超导电缆制作了小型超导悬浮线圈，并成功地实现了悬浮。除了直接驱动PID控制程序的主PC外，还使用本地PC和远程PC。浮置线圈的实时图像由带有CCD摄像机的本地PC拍摄。远程 ...更多信息 PC机可以获得该图像，也可以改变PID控制所需的参数。该系统连接到快速网络Super-SINET，并通过东京大学的远程控制进行磁悬浮实验。如上所述，本系统已经获得了足够复杂的能力，然而，具有直接图像数据处理的磁悬浮尚未完成。我们已经研究了与这种控制方案相关的一些问题，例如，由于相机的帧速率慢，控制的特征时间常数变得比激光传感器长得多。然而，通过实验确认，由于磁通量的守恒，超导线圈的运动的特征时间常数有效地较长，因此，可以应用使用图像数据的悬浮控制。另一方面，超导线圈中磁通量的守恒给出了自稳定磁悬浮的另一个有趣的发现，这应该在一些工程应用中得到应用。少

A new feedback control scheme using image-data processing is proposed for magnetic levitation of superconducting floating coils such as used in the Mini-RT project. In the conventional system of our previous studies, the position of a floating coil was measured using laser sensors, and the current of the levitating coil was controlled with an analog PID circuit. The new system has incorporated a digital control program with personal computers(PC). A graphical measurement-and-control software, LabVIEW is used in the system and a sufficient feedback-control capability was confirmed by levitating permanent magnets. A miniature superconducting floating coil was fabricated using silver-sheathed Bi-2223 high-temperature superconducting cables and this could also be successfully levitated. In addition to the main PC that directly drives the PID control program, a local PC and a remote PC are also used. The real-time image of the floating coil is taken by a local PC with a CCD camera. A remote … More PC can obtain this image and can also change the parameters necessary for the PID control. The system was connected to the fast network, Super-SINET, and the magnetic levitation experiment was conducted with a remote control from the Univ. of Tokyo. As described above, the present system has already attained sufficiently sophisticated capabilities, however, the magnetic levitation with a direct image-data processing has not yet been completed. We have examined some problems related with this control scheme, such as that the characteristic time constant of control becomes much longer than that with laser sensors due to the slow frame rate of a camera. However, it was confirmed by an experiment that the characteristic time constant of motion of a superconducting coil is effectively long due to the conservation of magnetic flux, and thus, the levitation control using image data can be applied. On the other hand, the conservation of magnetic flux in superconducting coils gives another interesting finding of self-stabilized magnetic levitation, which is supposed to be used in some engineering applications. Less