The soft robotic fish swims quickly and performs complex three-dimensional maneuvers.

New generation of underwater robots: speed and maneuverability without compromise.

Researchers from the Institute of Automation, Shenyang Branch, Chinese Academy of Sciences, have presented a soft robotic fish that achieves a record swimming speed of 2.13 body lengths per second - which corresponds to approximately 26 cm/s. This is not only a new record for body-caudal-fin (BCF) robots, but also proof that a soft design does not have to limit performance. Unlike traditional solutions, which usually forced a trade-off between speed and maneuverability, the new design allows both features to be achieved simultaneously.

The solution is based on a hybrid drive - a system composed of rigid and flexible elements. Local rigid constraints prevent unwanted deformation during operation, allowing for efficient force transfer. The alternating movements of two propulsion units simulate the action of antagonistic muscles in fish, generating high-frequency tail oscillations and effective propulsion.

Biomimetic swim bladder as a key to three-dimensional mobility.

The key to complex three-dimensional maneuvers is a new buoyancy control technology. Researchers have developed a biomimetic swim bladder that works on the principle of liquid-gas phase transition. This allows the robot to actively control its immersion and posture in space by changing the local density in different parts of the body.

The results of the experiments show that the robotic fish can regulate its posture in the range of -20° to 58°. This makes it possible to perform maneuvers such as S-shaped swimming, ascent, descent, and spiral ascent - all without the need for additional drives. This solution eliminates the need for complex control systems that are typical for traditional underwater robots..

Application in underwater monitoring and exploration

The new generation of soft underwater robots has the potential to significantly impact marine environment monitoring and resource exploration. Thanks to its flexibility, the robot fish can move in hard-to-reach places - such as between rocks, in crevices, or in areas with varying depths - without risking damage.

Its ability to move quickly and precisely control its posture makes it suitable for rapid transitions between observation points or for detailed analysis of local conditions. In the future, such devices may support ecological research, pollution monitoring, or even geological work on the seabed.

Scope and limitations of the experiment

The research was conducted under laboratory conditions, and the results were published in the journal IEEE/ASME Transactions on Mechatronics. Although the device achieves record speed and mobility, its operation has not yet been verified in real marine environments.

There is no information about the durability of the electro-hydraulic drive in long-term use or its performance under varying temperature and pressure conditions. Additionally, there is a lack of data on energy consumption during continuous operation - which is crucial for field applications.

Prospects for the development of underwater robotics

The new design shows that integrating biological mechanisms with electromechanical techniques can lead to significant advances in robot design. The example of the robot fish illustrates how a bio-synthetic approach - combining biological structures with electrical systems - can transform the field.

In the future, it may be possible to develop this technology into larger, autonomous devices or even teams of robots cooperating in real time. However, to achieve this, further research is needed on durability, energy efficiency, and cooperation capabilities in complex environments.

Prospects for the development of underwater robotics

The new design of the robot fish represents an important step towards realizing integrated bioelectromechanical systems that combine biological flexibility with technical precision. Thanks to its ability to actively regulate buoyancy through a biomimetic swim bladder, the device can change its posture without the need for additional drives, which reduces control complexity and energy consumption. This solution is crucial for applications in hard-to-reach underwater environments, where minimizing mechanical interaction with the environment is critical. In the future, this approach may be extended to teams of cooperating robots that support each other in real time while monitoring marine ecosystems or performing geological tasks.

until the energy consumption parameters and resistance to changes in pressure and temperature are documented. Without this data, it will not be possible to assess the real usefulness of the device in real marine conditions. It is worth emphasizing that although the experiments were conducted in a laboratory, their results show that the integration of biological mechanisms - such as buoyancy regulation and the action of antagonistic muscles - with electromechanical techniques can lead to significant advances in the design of underwater robots. This approach, sometimes called bio-syncretic, opens up new possibilities for the development of autonomous exploration systems that not only move quickly and precisely, but also adapt to complex environmental conditions.