A Parallel Inchworm Piezoelectric Actuator With an Active Swing Driving Biomimetic Structure

The designs and working principles of bioinspired inchworm-type piezoelectric actuators have been well studied in recent literature, with promising applications in precision engineering. However, it is challenging to extend the existing methods to cross-scale planar motion scenarios, which significantly limits the applicability of these actuators. In this article, a parallel, two-degree-of-freedom piezoelectric inchworm actuator is proposed, bioinspired by the skeletal structure of a snake’s spine with a novel active swing driving unit. Unlike conventional series-type actuators that utilize on separate modules for different directions of motion, the proposed design enables 2-D cross-scale parallel inchworm motion in the XY plane by actively switching between swing and translational modes using a shared clamp–drive–clamp assembly. A systematic design of the biomimetic piezoelectric actuator is presented, where modeling and analysis of the driving and clamping units are also supported by finite-element simulations. A design prototype was fabricated, and comprehensive experiments were conducted, demonstrating better performance than representative results in the literature. In particular, the actuator achieves high-performance planar cross-scale trajectory tracking and positioning with XY collaboration in full-step and sub-step scenarios. It has also been successfully applied in full-size chip stitching inspection experiments, highlighting significant potential for advanced semiconductor manufacturing, precision metrology, and inspection applications.