Rotary-linear piezoelectric actuator using a single stator

We report a piezoelectric actuator having a single stator with rotary and linear motions (RLPA). The stator is fabricated as a single metallic cube with a through-hole. The surface of the inner circle of the hole generates elliptical motions at each natural frequency, transferring the energy to an output shaft, when AC voltages at the appropriate resonant frequency are applied to the piezoelectric elements. This study clarifies the principle of rotary and linear motions and uses finite element methods (FEM) to show how the elliptical motions are generated. Modal analysis illustrated the shapes of the vibration modes and the natural frequencies, and the shape of the stator was designed accordingly. A dynamic analysis of the stator showed the generation of elliptical motion in the directions of the rotary and linear motions. The prototype RLPA was successfully actuated at the resonant frequencies, consistent with the dynamic analysis. The speed of the rotary and linear motions was obtained.