A 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 a magnetic field applied to it. We propose a mechanism to control the magnetic field for the three-dimensional levitated movement of the object. The mechanism consists of eight electromagnets, pole-pieces to connect the magnetic poles, a soft iron yoke, and permanent magnets embedded in the yoke to compensate the gravity force of an object: a small permanent magnet. Regulation of magnetic field and as a result, motion of the object are deeply related to geometric design of the pole-piece. Various pole-pieces were designed and tested experimentally. Motion of the object in the vertical direction is realized by controlling the sum of the electromagnet-currents for the regulation of magnetic field gradient. Motion on the horizontal plane is realized by controlling the ratio of each electromagnet-current for the regulation of location of maximum magnetic field. The results of several experiments show that the proposed mechanism is effective.