阵列永磁体产生旋转磁场的机理及实验

 诊疗微机器人外磁主动驱动是一种重要的可行的驱动方式,而如何产生合适的外部磁场是一个比较复杂的问题．相对于目前常用的通过电磁线圈组合产生驱动磁场方式,提出一种新的简单可行的永磁体组合产生旋转磁场方法,即圆周阵列永磁体并将其调整到对应的初始方位角后,同步转动在阵列中心区域产生旋转磁场,作为微机器人的主动驱动场．对于阵列中心区域的磁感应强度分布,作了理论分析和数值计算,并搭建了实验台．实验表明,采用边长为50 mm、高为18 mm的钕铁硼永磁体阵列,阵列数为6,阵列直径为275 mm时,可以在±50 mm×±50 mm×±20 mm阵列中心区域产生一个大小为0.012 T的均匀磁场,该磁场与永磁体同步旋转但是方向相反．这种新的磁场产生方法可以用于微机器人特别是诊疗微机器人的驱动,具有广阔的应用前景．

Mechanism and experiment research on rotational magnetic field generated by circumferentially arrayed permanent magnets

 Actively driving an inner micro-robot by an outer magnetic field for diagnosis is a feasible and crucial driven method. However, How to generate suitable outer magnetic is a complex problem. Comparing with the common methods adopting assembled electromagnetic loops to generate a driving field， an innovative and simple method was presented， by which permanent magnets were assembled to generate a rotational magnetic field. The circumferentially arrayed permanent magnet was adjusted to the corresponding original azimuth， and then synchronization rotation generated rotating magnetic field in the center of the array to work as the driving field of micro-robot. Furthermore， theoretic analysis and numeric calculation of the magnetic induction intensity distribution of the array center was carried out and a test-bed was established. The experimental results indicate that when circumferentially array six cubic magnets with 50 mm×50 mm×18 mm at the diameter of 275 mm， an even magnetic field of 0.012T can be generated in the central space，±50 mm×±50 mm×±20 mm， of the array. This magnetic field rotates with the same velocity as the outer magnet does， but in the reverse direction. The method， with wide application foreground， can be applied to generate a magnetic field to drive a micro robot， for diagnosis and treatment．