Trial Study of Ultra-Precision Magnetic Bearing

磁力轴承对于精密设备来说不够精确。在本研究中，首先介绍一个具有最佳状态回授控制器的二自由度磁悬浮轴承，并以电涡流位移感测器与电容测微计作为回授感测器。在轴不旋转的情况下，定位精度为15nm。然后，为了提高旋转精度，重复控制器被添加到轴承。最优重复控制器在120rpm下的旋转误差为250nm，这是由轴的轮廓误差以及传感器和电磁铁的布置引起的。

Magnetic bearings are not accurate enough for precision equipment. In this study, first, a two-degree-of-freedom magnetic bearing with an optimal state feedback controller is introduced Eddy current displacement sensors and capacitance micrometer are used as feedback sensors. The positioning accuracy is 15nm when the axis does not rotate. Then, to improve the rotational accuracy, a repetitive controller is added to the bearing. The rotational error with the optimal and repetitive controllers is 250nm at 120rpm which is caused by the profile error of the axis and by the arrangement of the sensors and electromagnets.