A Single-Clamp Inchworm Actuator with Two Piezoelectric Stacks

Inchworm piezoelectric actuators have attracted much attention in the field of precision positioning due to the advantages of a large stroke, high output force, and high resolution. However, traditional inchworm piezoelectric actuators use two sets of clamps and a set of drive structures to achieve stepping motion, which generally requires at least three piezoelectric stacks, resulting in a complex structure and the control system. Several methodologies have been advanced to minimize the utilization of piezoelectric stacks. However, there still exists the issue of excessive volume. Therefore, an inchworm piezoelectric actuator with a single-clamp and single drive structure is proposed in the study, which provides a compact size and smaller volume. The clamping mechanism comprises two sets of clamping feet with opposite displacement, which alternate contact with the guide frame and adjustable plate to ensure that the clamping mechanism always has frictional force and accomplishes the stepping motion. The testing of the actuator's step distance, output force, and other parameters was conducted utilizing a displacement sensor. Experimental results indicate that the actuator achieved a maximum speed of 174.3 μm/s and an output force of 8.6 N when the frequency and voltage were 19 Hz and 150 V.