Positioning of an inchworm type actuator with five degrees of freedom

Abstract

We previously proposed many micro actuators consisted of piezoelectric elements (piezo) and electromagnets. These micro actuators realized small displacement in unlimited working area by the principle of an inchworm. One of these micro actuators is a self-propelled Stewart platform. It moves in the three linear and rotational directions. However, the tilt angle of the stage was very small. In this paper, we proposed the actuator with five degrees of freedom consisted of six piezos and six electromagnets. Its structure is similar to a cyclohexane structure. The actuator proposed can be operated two modes. One is a stage motion mode, and the other is a self-propelled motion mode. In the stage motion mode, three bottom electromagnets are excited and the stage moves by the principle of an inchworm. In the self-propelled motion mode, three top electromagnets are excited and the actuator moves by the principle of an inchworm. Step displacement both in the self-propelled motion mode and in the stage motion mode is described. Moving speed and positioning are also discussed.