Transforming machines capable of continuous 3D shape morphing and locking.

Inspired by natural species that leverage morphological changes to realize multiple locomotion modes, diverse multimodal robots have been reported. While developments of small-scale actuators with continuous shape morphing and locking capabilities controlled by the same energy source are crucial for miniaturization of untethered multimodal robots, it remains elusive.

A research team led by Professor Yihui Zhang from Tsinghua University has developed thin-film-shaped small-scale actuators that enable microrobots to continuously transform their shapes and "lock" into specific configurations.

Their findings were recently published in the prestigious journal Nature Machine Intelligence.

(a) Illustration of the continuous shape morphing and locking for the actuator. (b) Properties of the key materials used in the actuator. (c) Exploded view of the electrothermal actuator and schematic illustration of its shape morphing and locking.

Synergistic material-structure design

Through innovative synergistic material-structure design, Zhang’s team developed an electrothermal actuator capable of continuous shape morphing and locking. Additionally, the Lego-inspired design strategy allows customized construction of complexly shaped actuators, such as a 4.5-centimeter-high, 0.8-gram mini-“Transformer” actuator.

“Transformer” actuator

Versatile exoskeleton

Serving as “morphable exoskeletons”, the actuators can be integrated with functional components like sensors and motors to build complex robotic systems. The research team developed a multifunctional wheeled microrobot that can morph into “sports car”“winged car” and “van” modes.

Wheeled microrobot

Furthermore, they also created the world’s smallest and lightest untethered terrestrial-aerial microrobot known in the relevant literature, measuring just nine centimeters in length and weighing 25 grams.

Untethered terrestrial-aerial micro-robot

Zhang’s study was conducted with colleagues from Tsinghua University’s Department of Engineering Mechanics, State Key Laboratory of Flexible Electronics Technology, Department of Mechanical Engineering, and Beihang University.

Information of the research article:

Xu et al. Transforming machines capable of continuous 3D shape morphing and locking. Nature Machine Intelligence, 2025. https://doi.org/10.1038/s42256-025-01028-4

(https://www.nature.com/articles/s42256-025-01028-4)