An Inchworm Using Levitation Caused by Vertical Vibration

We propose an inchworm type microactuator which uses levitation caused by vertical vibration. The vertical vibration is generated by a piezoelectric actuator. The inchworm usually consists of thrust elements and adhesive elements. The proposed inchworm type microactuator does not use any adhesive elements. Three masses are connected with two thrust elements which are stacked-type piezoelectric actuators. One mass which is at the center of the inchworm is also connected with a vertical vibrating piezoelectric actuator. The vertical vibration levitates the central mass and eliminates the friction. The other masses without vibrating elements have constant friction force. By controlling the phase of the thrust elements and vibrating element, the inchworm moves in the liniear directions. The position of the inchworm is measured, and some experimental results indicate the feasibility of the proposed inchworm. The mechanism described in this paper is effective in a precise positioning system in a cleanroom.