An Inchworm Using Levitation Caused by Vertical Vibration

Abstract

SUMMARY 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 clamp elements. The proposed inchworm‐type microactuator however does not use any clamp elements. Three levitation elements are connected with two thrust elements which are stacked piezoelectric actuators. The levitation element consists of a mass, a piezoelectric actuator, and a plate. The vertical vibration of the piezoelectric actuator lifts the levitation elements and eliminates the friction. By controlling the phase of the horizontal and vertical piezoelectric actuators, the inchworm moves in a linear direction. The levitation height and the position of the inchworm are measured, and experimental results show the feasibility of the proposed inchworm. The mechanism described in this paper is effective in a precise positioning system in a clean room.

A 3‐DOF Inchworm Using Levitation Caused by Vertical Vibration

“…This value is smaller than that of the ac current used in Ref. []. In addition, although high‐frequency oscillation at 1.8 was measured for levitation mechanism B, vibration had no effect on the proposed mechanism for controlling friction, regardless of the levitation.…”

“…It can be seen that levitation occurs over time. It is evident that the amount of levitation of levitation mechanism D from mechanism A is affected by the drive frequency , and consequently the drive frequency was adjusted so that in this experiment the amount of levitation of each levitation mechanism was approximately 10 μm with the amplitude of the applied voltage constant. Consequently, the drive frequencies of the high‐frequency voltage applied to piezoelectric actuators A–D were 11.8 kHz, 11.2 kHz, 10.7 kHz, and 10.8 kHz, respectively.…”

“…Noncontact handling technology and movement technology using vibration have been reported [7][8][9][10]. We have proposed an inchworm mechanism for movement making use of a levitation mechanism involving a piezoelectric actuator that vibrates at high speed in the vertical direction, and have demonstrated its effectiveness in experiments on reciprocating motion with one degree of freedom [11].…”

Levitation Caused by the Vertical Vibration of a Piezoelectric Actuator

“…One of the works was the small mobile machine with piezoelectric elements, in which the machine moved based on the inchworm-movement principle through the combination of levitation mechanisms employing piezoelectric elements that vibrate in the vertical direction [2,3]. One of the works was the small mobile machine with piezoelectric elements, in which the machine moved based on the inchworm-movement principle through the combination of levitation mechanisms employing piezoelectric elements that vibrate in the vertical direction [2,3].…”

“…This technology takes advantage of the piezoelectric element vibration to generate air film, which results in a contactless state between objects. In our works [2,3], the input signals to obtain the desired levitation height were determined through experiments. So far, the relationship between the piezoelectric element vibration and the thickness of the generated air film is dictated in the studies, the vibration states are acquired through experiments, not through simulation [5,6].…”