MICRO SWIMMING MECHANISMS PROPELLED BY EXTERNAL MAGNETIC-FIELDS

A new type of micro swimming mechanism is proposed for microrobots wor king in water. It is composed of a small magnet attached to a spiral w ire. An external alternating magnetic field causes the magnet to rotat e due to magnetic torque. As a result, the mechanism can swim propelle d by waves traveling along the spiral. The swimming velocity increases linearly with increasing excitation frequency, and the increasing rat e depends on the shape of the spiral. The experimental velocity agreed with the calculation result based upon Lighthill's theory.