Rotary Inchworm-Type Piezoelectric Actuator

Abstract

The authors have developed a rotary inchworm-type actuator which has a rotor directly driven by a stator, and can operate both clockwise and counterclockwise with potential good repeatability for highly precise positioning. The stator comprises a torsional-movement multilayered piez-oelectric actuator (TMPA) and two sets of longitudinal-movement multilayered piezoelectric actuators (LMPA). The two sets of the LMPA act as a clutch mechanism and transfer the torque from the TMPA to the rotor.
As a result of the experiment with the actuator made experimentally, it has been proved that the rotor moves as expected. It has also been found that the rotational speed of the rotor can be controlled in the range from 10^-7 to 10^-4 rad/s by changing the applied voltage to the TMPA and the driving frequency and that the maximum torque of 2.0kg•cm can be realized when the voltage reaches 800V_p-p. Using the bending and torsional movement of the stator, we explained the torque characteristics that the rotational speed of the rotor decreased with the increase of load.