Southampton, United Kingdom – Engineers have developed a robotic wing that senses water flow and adapts its shape, dramatically improving underwater stability. The innovation draws on the movements of birds and fish, allowing the wing to automatically respond to disturbances in currents.

The University of Southampton-led team reports that the wing reduced unwanted uplift impulse by 87 per cent compared to rigid wings on typical autonomous underwater vehicles (AUVs). It also reacts up to four times faster than other soft wings and consumes five times less energy than systems that rely on thermal energy for shape changes.

Rigid AUV bodies often struggle with sudden currents, expending energy to counteract forces. To address this, the researchers applied proprioception—the body’s internal sense of position and movement. Birds sense airflow through feathers, while fish detect water currents via the lateral line and fin rays.

The new wing uses an innovative e-skin made of flexible liquid metal wires encased in silicone, acting like nerves that signal as the wing bends. Hydraulic tubes in the body adjust stiffness and camber automatically in response to water flow.

“Instead of building ‘tougher’ robots designed to fight the ocean’s power, we are moving toward smarter, softer machines that work in synergy with the environment,” said Leo Micklem, lead author of the study.

Tests subjected the wing to various disturbances, comparing it to rigid and basic soft wings without sensing abilities. The results showed roughly double the stabilisation achieved by a barn owl in glide, although direct comparisons should be interpreted cautiously.

Professor Blair Thornton, coauthor from Southampton, said, “Ocean environments are dynamic and unpredictable, so robots must continually sense what is happening around them and respond accordingly. Integrating soft materials for sensing and control brings robots closer to the adaptive systems needed for reliable underwater operation.”

Challenges remain in scaling the technology, integrating it with AUVs’ rigid components, and ensuring real-world robustness, though more powerful actuators could further enhance stability.

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