Soft Underwater Robot Swims in 3D with Just Two Actuators

A Breakthrough in Soft Underwater Robotics

Engineers at North Carolina State University have created an innovative soft robot that glides underwater with remarkable agility. By drawing inspiration from the feather star, a marine invertebrate known for its graceful movement, the research team designed a machine that can steer in full 3D space using just two pneumatic actuators.

During lab testing reported in October 2026, the prototype achieved impressive speeds of up to 1.64 body lengths per second. It also demonstrated the ability to execute sharp turns at roughly 90 degrees per second. What makes this feat so unusual is that the robot achieves high maneuverability without relying on heavy motors or complicated artificial intelligence.

Understanding Mechanical Intelligence

In traditional robotics, achieving smooth motion underwater usually requires a messy collection of pumps, valves, cables, and lines of complex software code. Adding more directions of movement typically means adding more hardware, which creates extra weight and increases the risk of mechanical failure.

The NC State team took the opposite approach by relying on mechanical intelligence. This concept means letting the physical structure and material properties of the robot handle tasks that would normally require powered control systems.

Instead of using electronics to reset the positioning after every stroke, the robot relies on flexible, springy materials. The four wings naturally snap back into place on their own, drastically reducing the amount of hardware needed onboard.

Inspired by the Marine Feather Star

While many current robotics projects focus on humanoids or factory automation arms, this project looked deep into the ocean for answers. The feather star uses multiple arms working together to float, swim, and change directions smoothly in moving currents.

Rather than trying to duplicate every single arm of the biological creature, the engineers extracted the underlying physical principle. By using exact timing and structural flexibility, a simple set of inputs can unlock a wide range of movements.

The prototype drives four elastic wings using just two air-powered pneumatic actuators. Pulses of air pressure flex the wings, converting simple pushes into lift, forward movement, sharp turns, or precise positioning in one spot.

Working With Water Currents Instead of Fighting Them

Fluid dynamics play a crucial role in how this soft swimmer moves through the water. Every time a wing strokes, it creates small local currents in the surrounding water. The robot is built to ride these subtle fluid movements during its next stroke rather than fighting against them with brute force engine power.

Measuring speed relative to body length allows researchers to accurately compare how efficient the design is, regardless of the size of future models.

Current Limitations and Future Steps

While the prototype's performance is impressive, it is not yet completely wireless or autonomous. The robot is currently tethered to external lines for power supply and compressed air control.

The development team is working on a wireless version that carries its own power supply, pressure tanks, and sensors. The ultimate goal is to create a fully self-contained system that maintains the simplicity of the original design.

The research was published in Science Advances under the title Minimal-Actuation Feather Star-Inspired Soft Swimmers for Multimodal 3D Maneuverability (DOI: 10.1126/sciadv.aeg9211). Once liberated from its tetherUSDT+0.33%, this technology could be useful for environmental monitoring, underwater pipeline inspections, and retrieving small objects from fragile ocean ecosystems.

Broader Technology and Market Landscape

Robotics innovations like this soft swimmer highlight how hardware design is changing alongside advances in digital systems. While artificial intelligence and automated systems grab headlines across tech markets, physical innovations continue to solve complex real-world challenges.

In parallel technology news, major digital assets show ongoing movement across global markets, with BitcoinBTC-0.35% trading near $81,792 and EthereumETH-0.42% around $2,406 during late October 2026 reporting. Past performance of digital assets is no guarantee of future returns.