Simplified octopus-inspired swimming robot with soft asymmetric arms can replicate swimming patterns

Researchers at the National University of Singapore have developed a new robot inspired by one of the most intelligent aquatic animals on Earth: the octopus. This robot, presented in a paper published on the arXiv pre-print server, could be used both to complete real-world tasks underwater and to study the bio-mechanical underpinnings of octopus swimming.

“Our research journey began long ago with studying diverse principles for reaching and grasping, locomotion and swimming,” said Prof. Cecilia Laschi, who supervised the study, told Tech Xplore.

Compared to many other marine animals, octopuses are extraordinarily agile, as they can both swim rapidly underwater and manipulate objects in their surroundings. The key objective of this recent study was to develop a robotic system that reliably replicates the octopus’ advanced underwater skills.

“The initial goal of our work was to develop a swimming platform and, while reviewing previous literature, realized that existing designs were overly complicated, particularly when it came to mimicking the octopus’ eight arms,” said Yiyuan Zhang, one of the first authors of the paper.

“Our primary goal is to create a more accessible and easy-to-build platform that not only captures the essence of octopus movement but also encourages broader research and innovation in underwater robotics.”

The octopus-inspired robot developed by Zhang and his colleagues has eight soft arms that are actuated via an innovative umbrella-like mechanism. This innovative mechanism, which is powered by two motors rotating at a constant speed, eliminates the need to deploy eight different motors and individual actuators for each arm.

“As the robot moves through the water, its arms gently open to create a low-drag shape, allowing it to glide effortlessly,” said Zhang. “Then, when it’s time to propel itself forward, the arms quickly close and stiffen, generating powerful thrust—just like an octopus does! This design not only simplifies the mechanics and control but also enhances efficiency, making the robot both effective and easy to manage.”

With their innovative robot design, the researchers were able to closely replicate the swimming pattern observed in octopuses. In initial tests, their robot was found to efficiently propel itself forward, reaching a peak speed of 314 mm/s during its second power stroke.

Compared to previously introduced octopus-inspired robotic platforms, the team’s proposed system is far less complex, yet it attains a comparable swimming performance. A further advantage of the new robot is its energy-efficiency, as it could travel long distances underwater while minimizing power consumption.

“This design also addresses a common issue in similar robots: backward movement when arms open for the next propulsion,” said Zhang.

“The practical applications for our octopus-inspired robot are vast, including underwater exploration, environmental monitoring, and even search and rescue operations. We’re currently focusing on using this platform to advance our research into octopus-like underwater movement and manipulation, which could open new possibilities in robotics.”

The new robotic platform introduced by Prof. Laschi, Zhang and their colleagues could soon inspire the development of other simplified bio-inspired underwater robots.. Notably, this recent paper is part of a broader research project focusing on octopus-inspired robotics.

The team’s broader project has already helped to pin-point some of the factors contributing to the advanced dexterity and swimming abilities of these fascinating aquatic animals. In their next studies, the researchers plan to explore additional design strategies that could further improve the performance and energy-efficiency of octopus-inspired systems.

“Our plan is to revolutionize the way underwater robots are designed and built and bring their operational capabilities and autonomy, in control and energy, to the next level,” added Prof. Laschi.

“In addition to underwater applications, we explore the application of our new technologies in diverse fields, like the biomedical field, for assisting elderly people, or industry. We would like to acknowledge the funding support for our research projects, including DESTRO (‘Dextrous, Strong yet Soft Robots’ from MAE, Italy, and A*STAR, Singapore), REBOT (‘Rethinking Underwater Robot Manipulation’ from the Singapore Ministry of Education), and the RoboLife project (‘Soft Robots with Morphological Adaptation and Life-like Abilities’ from the National University of Singapore).”

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