Aquatic robot inspired by flatworms can swim in harmony with nature

The ability of robots to navigate aquatic environments is crucial for a variety of applications, such as mapping pollution levels and monitoring the health of coral reefs. However, challenges remain.

The commotion from the noisy propellers of these underwater devices can cause unnecessary disturbances, and even harm wildlife.

The natural obstacles in these aquatic settings – like plants, underwater animals, and floating debris – further test the navigation abilities of these robotic swimmers.

Tiny robot with big potential

A team of experts has introduced a novel solution to these issues. They have developed a compact, nimble robot that is capable of navigating tight corners and carrying payloads much heavier than itself.

Remarkably, the aquatic robot is smaller than the size of a credit card and weighs only 6 grams (0.2 ounces).

This tiny device is designed to work in confined environments, making it perfect for tasks like inspecting waterborne machines and studying the aquatic ecosystem of compact spaces, like rice fields.

Herbert Shea, head of EPFL‘s Soft Transducers Lab, elaborated on the challenges of developing aquatic robots.

“In 2020, our team demonstrated autonomous insect-scale crawling robots, but making untethered ultra-thin robots for aquatic environments is a whole new challenge. We had to start from scratch, developing more powerful soft actuators, new undulating locomotion strategies, and compact high-voltage electronics,” said Shea.

Movements of marine flatworms

Breaking away from traditional propeller-based systems, this new robot propels forward with silently undulating fins that are inspired by the movements of marine flatworms.

This novel design, coupled with its feather-weight structure, allows the robot to float on the water’s surface and blend into its natural surroundings without causing a stir.

Florian Hartmann, a former EPFL researcher who is now a research group leader at the Max Planck Institute for Intelligent Systems, in Stuttgart, Germany, offered an interesting perspective.

“Our design doesn’t simply replicate nature; it goes beyond what natural organisms can achieve,” he said.

By oscillating its fins up to 10 times faster than marine flatworms undulate, this new robotic swimmer achieves impressive speeds of 12 centimeters (4.7 inches) per second, which is equivalent to 2.6 body lengths per second.

With four artificial muscles driving the fins, the robot exhibits unprecedented maneuverability, which allows controlled backward and sideways swimming.

Potential applications of aquatic robots

The researchers developed a compact control system that charges the robot’s actuators with up to 500 volts at a power of 500 milliwatts – four times less than that of an electric toothbrush.

Despite using a high voltage, the tiny robot’s low currents and shielded circuitry make it perfectly safe for its environment.

The light sensors on the robot act as its eyes, enabling it to detect and follow underwater light sources autonomously .

The potential applications of this swimming robot include ecological studies, pollution tracking, and precision agriculture. However, the researchers are not finished with the robot just yet.

“We aim to extend operating times and enhance autonomy. The fundamental insights gained from this project will not only advance the science of bioinspired robotics but also lay the foundation for practical, lifelike robotic systems that harmonize with nature,” said Hartmann.

The future of bioinspired robotics

The team now plans to focus on expanding this miniature aquatic robot’s capabilities. They wish to integrate more advanced sensors, improve battery life, and refine autonomous decision-making.

Future iterations could feature enhanced AI-driven navigation, which would allow these tiny swimmers to collaborate in groups (much like schools of fish) for large-scale environmental assessments.

In the realm of precision agriculture, such robots could assist in monitoring irrigation systems and identifying nutrient imbalances in flooded crops.

They may also play a role in underwater infrastructure inspections, assisting in detecting pipeline leaks or assessing the condition of offshore wind farms.

By combining cutting-edge robotics with insights from nature, researchers are not only overcoming long-standing challenges in aquatic exploration but also paving the way for a new generation of intelligent, adaptable, and environmentally harmonious robotic systems.

The full study was published in the journal Science Robotics.

Image Credit: © EPFL-LMTS

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