Development of a vibration detector using a magnetic spring and an astable rotational-pendulum with a plunger permanent magnet inserted in to the uniform magnetic field

使用磁性弹簧和插入均匀磁场的柱塞永磁体的非稳态旋转摆开发振动检测器

• 批准号: 11640405
• 负责人: OTAKE Yuji
• 金额: $ 2.3万
• 依托单位: University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11640405/
• 关键词: seismometer; astable rotational pendulum; magnetic spring; electric magnet; solenoid coil; highly sensitive; wideband

In this study, we have developed a seismometer more sensitive than present one using a new principle. It's an astable rotational pendulum that a plunger permanent magnet is inserted in to the uniform magnetic field generated by a window frame type permanent magnet and attached to a rotational axis outside of the bore of the magnet. The results obtained in this study were as follows. 1. The prototype of a seismometer employing a rotational pendulum and a magnetic spring has been built and been evaluated by experiments. The result of the experiments showed that the natural period of the pendulum which could be an index of seismometer's performance was more than ten seconds. This period is almost comparable to that of usual highly sensitive/wide band seismometers. 2. The prototype with a feedback circuit, a feedback coil and a capacitance displacement sensor worked as a servo type seismometer. However feedback parameters were not so optimal at present stage and so should be tuned to the best. 3. The natural period of the prototype could be changed with the magnetic spring. These values of the period are consistent with theoretical calculations. 4. The magnetic field uniformity of the window frame magnet is important for stable operation of the prototype. The further uniformity is necessary for more stable operation, through we could get the value of 10^<-3>. 5. To reject the drift of a spring constant caused by a temperature change, we have procured stable elastic modulus metal. The leaf springs using the metal will be installed as x-hinges for the rotational axis of the prototype. From the above mentioned results, the methods to improve the operation stability of the prototype were figured out as well as it was confirmed that the rotational pendulum could be worked in order to a theory.

在这项研究中，我们开发了一个更灵敏的地震仪比现有的一个使用新的原则。它是一种在窗框式永磁体产生的均匀磁场中插入一个柱塞式永磁体，并将其固定在永磁体孔外的旋转轴上的非稳态旋转摆。本研究获得的结果如下。1.利用旋转摆和磁弹簧组成的地震计样机已经建成，并进行了实验验证。实验结果表明，摆的固有周期大于10秒，可以作为地震计性能的一个指标。这个周期几乎可以与通常的高灵敏度/宽频带地震仪相媲美。2.该原型具有反馈电路、反馈线圈和电容位移传感器，可用作伺服型地震仪。然而，反馈参数在现阶段并不是最佳的，因此应该调整到最佳。3.利用磁力弹簧可以改变样机的固有周期。周期的这些值与理论计算是一致的。4.窗框磁体的磁场均匀性对样机的稳定运行至关重要。进一步的均匀性对于更稳定的操作是必要的，通过我们可以得到10^的值<-3>。5.为了抑制由温度变化引起的弹簧常数的漂移，我们已经获得了稳定的弹性模量金属。使用金属的片簧将被安装为原型旋转轴的x铰链。根据实验结果，提出了提高样机运行稳定性的方法，并证实了旋转摆的工作原理。

项目成果

A.Araya: "Geophysical Observations using Long-baseline Interferometers, Gravitational Wave Detection II"Proceedings of the 2nd TAMA International Workshop, Universal Academy Press. Inc.,. 165-170 (2000)

A.Araya：“使用长基线干涉仪进行地球物理观测，引力波探测 II”第二届 TAMA 国际研讨会论文集，环球学院出版社。