A research team from Harbin Institute of Technology has developed a series of centimeter‑scale reconfigurable piezoelectric robots with a built‑in‑ceramic actuation unit, providing new insights for miniature reconfigurable robot design, as reported in a recent issue of Engineering.

Traditional reconfigurable robots often rely on bulky electromagnetic motors and complex transmission mechanisms, making miniaturization difficult and limiting their use in confined spaces. In contrast, the new robots adopt piezoelectric actuation, which features fast response, simple structure, and no transmission mechanisms. The core is a compact built‑in‑ceramic actuation unit measuring 44 mm × 10 mm × 12.5 mm and weighing 6.50 g, operating in the first‑order bending resonant vibration mode to generate oblique trajectories on the driving feet via an impact‑jump motion. This actuation unit reaches a locomotion speed of 90.3 body length per second and a carrying capability of 31.6 times its self‑weight.

The researchers designed a highly integrated module that combines the actuation unit with control, communication, and power‑supply components. This untethered module achieves a movement speed of 590 mm per second and supports stable wireless control. Multi‑position magnetic connections are embedded in the module housing, enabling flexible assembly into chain‑type and ring‑type configurations. A configuration evaluation method is proposed to help select suitable structures for specific tasks by calculating configuration weights based on end and side connection ratios.

Experimental tests show that these reconfigurable robots adapt well to various flat terrains. Different configurations can cross wide grooves, span narrow slits, pass through narrow channels, navigate tight bends, and traverse height‑difference surfaces. The robots also support functional expansion; when equipped with a vision sensing unit, they can perform wireless image capture for environmental reconnaissance. The built‑in ceramic arrangement protects the actuation source, enhances durability, and supports dustproof and waterproof performance, while the hollow structure helps lower resonant frequency and increase vibration amplitude.

This work addresses challenges in miniaturization and reconfiguration of small‑scale robots. The integrated design and magnetic reconfiguration strategy support untethered, high‑speed locomotion and multi‑scenario adaptation. The robots show potential for environmental exploration, multi‑task operations, and confined‑space detection. Future improvements may focus on more efficient actuation methods, full built‑in integration of components, position feedback, and self‑reconfiguration strategies to broaden practical applications.

The paper “Centimeter-Scale Reconfiguration Piezo Robots with Built-in-Ceramic Actuation Unit,” is authored by Yu Gao, Jing Li, Shijing Zhang, Jie Deng, Weishan Chen, Yingxiang Liu. Full text of the open access paper: https://doi.org/10.1016/j.eng.2025.06.043. For more information about Engineering, visit the website at https://www.sciencedirect.com/journal/engineering.