A robot inspired by earthworms

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A robot inspired by earthworms

Scientists from the Adolphe Merkle Institute and Case Western Reserve University (Cleveland, USA) have developed a flexible robot, inspired by earthworms, that can squeeze into small spaces and move in all directions regardless of the surface.

Soft robots with worm-like mechanical properties and shape can, in principle, move over rough terrain and into tight spaces inaccessible to other robots. These devices could perform multiple and varied functions ranging from search and rescue operations, to underground exploration and pipeline inspection, to biomedical procedures such as endoscopy or colonoscopy.

However, unlike the species from which they are inspired, most of these robots contain rigid elements, such as motors, which cause certain mechanical limitations. To remedy this, researchers from the Polymer and Materials Chemistry Group at the Adolphe Merkle Institute, in collaboration with their American partner, have developed an extremely flexible robot with a fully modular body composed almost entirely of soft polymers.

Playing with temperature to activate the beast
This device consists of segments, actuators with a double layer of polymers, which change shape under the action of heat or cold. By individually activating the segments by heating them electrically, it is possible to control the robot’s movements with high precision. Like an earthworm, the robot moves by sequentially contracting and expanding its individual segments. This operating principle also allows the robot to move through spaces that are smaller than its diameter in its resting state.

A technique to be perfected
The picture would be almost perfect if the new robot were not excessively slow and its movements did not require huge amounts of energy. The team of scientists is optimistic, however: the robot’s modular architecture should make it possible to improve its performance by using faster and more energy-efficient bending actuators. Moreover, the current version is externally powered and controlled, whereas it could become autonomous with the integration of flexible batteries and independent control systems.

The results of this research project have been published in the leading scientific journal Advanced Materials . This work was carried out with joint funding from the US and Swiss National Science Foundation under the International Partnership for Research and Education (PIRE) Bio-inspired Systems and Materials program.

> Muff, L. F.; Mills, A. S.; Riddle, S.; Buclin, V.; Roulin, A.; Chiel, H. J.; Quinn, R. D.; Weder, C.; Daltorio, K. A. Modular Design of a Polymer-Bilayer-Based Mechanically Compliant Worm-like Robot. Advanced Materials 2023, 34, 2210409. https://doi.org/10.1002/adma.­202210409.