A miniature multi-DOF ring-shaped piezoelectric actuator capable of driving both flat and spherical movers

Abstract

In this paper, a novel miniature piezoelectric actuator was proposed with a compact ring structure and four driving teeth. The prominent feature was that the ring-shaped piezoelectric actuator could not only drive multiple types of movers, but also achieve multi-DOF motions by using the hybrid and traveling vibration modes. On the one hand, the four teeth were driven by only one ring-shaped piezoelectric actuator instead of four actuators separately, and were arranged circumferentially capable of supporting and driving both flat and spherical movers. On the other hand, the 4th-order radial and axial vibration modes were degenerated to achieve linear motions in the ox and oy directions; while two 3rd-order axial vibration modes were hybrid to realize the rotary motion around oz direction. FEM (finite element method) was employed to determine parameters and verify the working principles. Then, a prototype with a size of about Φ60 × 13 mm3 and a weight of 40 g was fabricated, and the characteristics were tested. Experimental results showed that the maximum speed, resolution and load realized in the linear motions were 23.3 mm/s, 0.7 μm, and 200 g, respectively; while that in the rotary motions were 0.8 rad/s, 11.5 μrad, and 200 g, respectively. The multi-DOF motions were successfully achieved by degenerating different vibration modes of the same ring structure.