A novel miniature multi-DOF three-ring-shaped piezoelectric actuator for small and lightweight robot joints

Abstract

Piezoelectric actuators are extensively used in aerospace and precision instruments due to their high precision and simple structure. However, conventional piezoelectric actuators intended for multi-degree-of-freedom (multi-DOF) motion typically have high mass and low space utilization due to their complex structures. This makes them unsuitable for use in the joints of lightweight robots. To address these issues, we propose a novel one-piece multi-DOF piezoelectric actuator. This actuator can achieve multi-DOF motions with the mover such as flat plates or spherical shells. Through finite element simulation analysis, we determined the primary dimensional parameters of the stator. We then fabricated an experimental prototype with dimensions of approximately Φ40 × 3 mm, weighing about 23.5g. Experimental results indicate that the prototype achieves a maximum rotary motion speed of 5.03 rad/s and a maximum linear motion speed of 9.17 mm/s, with a maximum load capacity of 50g. The actuator exhibits a minimum rotary motion resolution of 18 μrad and a minimum linear motion resolution of 2 μm. This study demonstrates that such multi-DOF actuators have great potential in areas such as small and lightweight precision robots due to their compact structure, small volume, light weight, and high precision.