Development of a 3-DOF rotary piezoelectric actuator with compact structure

Piezoelectric actuators have been widely applied in precision electromechanical equipment due to their high resolution, fast response, and flexible structure. However, existing rotary piezoelectric actuators still face the contradiction between the structure miniaturization and the multi degrees of freedom (MDOF) motion output. Therefore, a novel rotary piezoelectric actuator is developed to achieve characteristics of compact structure and 3-DOF motions in this study, in which an orthogonal axis support system for a spherical rotor is adopted. And a stick-slip combined direct excitation scheme is designed to obtain large working range and microradian-resolution outputs. The configuration and motion principle are designed and illustrated in detail. The statics model is established for structural optimization design and parameters determination. The actuator prototype is fabricated and tested, a compact structure is achieved with an overall size of 72 mm in diameter and 80 mm in height. 3-DOF full circle rotary motion outputs around axes X, Y and Z are achieved, the corresponding maximum rotary speeds are 0.423, 0.438, and 0.975 rad/s, and the corresponding resolutions are 4.14, 4.28 and 2.32 μrad, respectively. Moreover, the prototype has successfully completed the imaging application of multi objects in large working range. The experimental results preliminarily demonstrate the potential application of the 3-DOF rotary piezoelectric actuator in the field requiring large working range and microradian-resolution.