A prototype mechanism for three-dimensional levitated movement of a small magnet

This paper deals with basic technologies for noncontact manipulation of small objects using magnets in micromachine applications. A small permanent magnet is manipulated by controlling the magnetic field applied to it. We propose a prototype mechanism to control the magnetic field for 3D levitated movement of an object. The prototype consists of eight electromagnets, pole-pieces to connect the magnetic poles, a soft iron yoke, and permanent magnets embedded in the yoke to compensate for the gravitational force of an object (a small permanent magnet). Regulation of a magnetic field and, as a result, motion of the object are strongly related to the geometric design of the pole-piece. A strategy for the pole-piece design is proposed and tested experimentally. Motion of the object in the vertical direction is realized by controlling the sum of the electromagnet currents for regulation of magnetic field gradient. Motion in the horizontal plane is realized by controlling the ratio of each electromagnet current for regulating the location of the maximum magnetic field. Results of several experiments show that the proposed prototype is effective.