Noncontact Manipulation of Magnetic Objects with an Array of Permanent Magnets and Linear Servomotors

This paper presents the concept, implementation, feedback control, and experimental verification of a noncontact magnetic manipulator that relies on a controllable array of permanent magnets to manipulate magnetized objects inside a workspace encircled by the magnets. To gain control over the aggregate magnetic field inside the workspace, the position of each magnet is independently controlled by a linear servomotor that dynamically changes the distance between that magnet and the workspace. By feedback control of the array of servomotors, the magnetic force applied to a magnetized object inside the workspace is dynamically adjusted to steer it along a desired reference trajectory. The successful steering of a small magnetic bead is demonstrated by experiments performed on a planar magnetic manipulator, designed and prototyped with six linear servomotors and six permanent magnets.