A Nature‑Inspired Robotic Wing Improves Underwater Stability
Bold claim: smarter, softer tech can outmatch rigid machines in the ocean. Researchers are drawing on nature to design a robotic wing that not only senses water changes but adapts on the fly, delivering unprecedented stability in turbulent conditions.
Conceptually, the project mirrors how birds and fish adjust in real time. The wing monitors disturbances in water flow and automatically reshapes itself to maintain steady motion. Led by the University of Southampton, the team argues that their soft robotics and electronic-skin (e-skin) approach could narrow the gap between automated devices and living animals in terms of maneuverability and efficiency.
In experiments, this innovative wing cut the uplift impulse—the jolt from sudden underwater currents—by about 87% compared with conventional rigid wings used on autonomous underwater vehicles (AUVs).
The study, published in npj Robotics, also reports that the wing responds up to four times faster than comparable soft-wing systems and uses five times less energy than methods that rely on thermal actuation to change shape.
Traditional AUV wings struggle when buffeted by abrupt currents and waves, often wasting energy counteracting those forces with rigid bodies. The Southampton team sought an alternative: harness proprioception—the internal sense of a body’s position, movement, and forces—to enable smarter adaptation.
To illustrate, birds sense air disturbances through their feather arrays, while fish detect shifts in water flow via their lateral line system and fin rays. Applying this principle, engineers devised an e-skin made from flexible liquid-metal wires encased in silicone to act like nerves. This network senses subtle changes as the wing bends and sends the information to control systems.
Inside the wing, two hydraulically pressurized tubes adjust stiffness and camber automatically, enabling seamless, real-time responses to flow disturbances.
Lead author Leo Micklem (affiliated with the University of Southampton and now at Portland State University) explains: rather than building sturdier robots to fight the ocean, the aim is to create smarter, gentler machines that work with the environment instead of against it.
In tests, researchers exposed the wing to disturbances of varying shapes and magnitudes and compared results with a standard rigid wing and a simpler soft wing lacking proprioceptive sensing.
The outcomes were striking. The proprioceptive, nature-inspired wing demonstrated roughly double the stabilization capability of a barn owl during glide—though direct comparisons should be treated cautiously due to species differences.
The findings suggest substantial gains in stability, responsiveness, and energy efficiency, potentially enabling more agile and safer underwater robots that consume far less energy to stay steady in rough seas.
Professor Blair Thornton of Southampton underscores the broader challenge: ocean environments are inherently dynamic and unpredictable, so robots must continually sense their surroundings and adapt. While soft materials have shown promise for propulsion, integrating them with sensing and control moves soft robotics closer to the adaptive behavior needed for reliable operation in real underwater settings.
The researchers acknowledge hurdles ahead, including scaling the technology, integrating soft components with the rigid architecture of existing AUVs, and ensuring reliability in real-world deployments. They also note that stronger actuators could push stability even further.
The study, Harnessing proprioception in aquatic soft wings for hybrid passive–active disturbance rejection, appears in npj Robotics and is accessible online.
Would you agree that blending soft materials with intelligent sensing represents the future of underwater robotics, or do you think the simplicity and robustness of traditional rigid designs still hold the upper hand? Share your thoughts in the comments.
