Bioinspired Legged Underwater robots for Ecological monitoring and Exploration

Project Information

BluE

Grant agreement ID: 101061354

DOI

10.3030/101061354

Project closed

EC signature date 21 October 2022

Start date 1 September 2023

End date 31 August 2025

Funded under

• Marie Skłodowska-Curie Actions (MSCA)

Total cost

No data

EU contribution

€ 165 312,96

Coordinated by

AGENCIA ESTATAL CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS
Spain

Periodic Reporting for period 1 - BluE (Bioinspired Legged Underwater robots for Ecological monitoring and Exploration)

Reporting period: 2023-09-01 to 2025-08-31

Summary of the context and overall objectives of the project

The BluE project advanced the integration of bioinspired legged robots into marine ecological monitoring, addressing the growing need for sustainable, low-impact ocean observation systems. It directly supports EU priorities under the Mission Restore our Ocean and Waters, the European Green Deal, and the development of the Digital Twin of the Ocean.

The project focused on SILVER2, a legged underwater robot designed to move on the seabed, where traditional propeller-driven vehicles face limitations. BluE achieved major technological progress through the complete refurbishment of SILVER2, including a new waterproof actuator canister, an integrated power and control board with early-leak detection, and full migration to ROS 2. These developments led to the creation of the Open Toolkit for Underwater Robotics, a publicly available hardware–software platform that lowers entry barriers for underwater robotic research and education.

BluE also validated a new mobile–fixed observatory approach by coupling a crawler robot with the OBSEA cabled observatory for autonomous visual monitoring, demonstrating a scalable method for benthic ecological observations. In parallel, it delivered the first open simulation environments for underwater legged robots (silver2_gz and silver2_stonefish), enabling realistic modeling and reinforcement learning of underwater locomotion and control.

The project combined robotics, electronics, and marine ecology training, fostering multidisciplinary expertise and new collaborations. Its open-science approach ensures all results—software, hardware, and datasets—are freely accessible, promoting reproducibility and sustainable innovation.

By pioneering legged, low-disturbance robots for seabed exploration, BluE contributes to Europe’s transition toward intelligent and environmentally responsible ocean monitoring technologies.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The BluE project advanced the field of bioinspired underwater robotics by developing, upgrading, and validating new technologies that enable legged robots to operate autonomously on the seabed for ecological monitoring and exploration.

The main experimental activities focused on the modernization and validation of the SILVER2 legged robot, which underwent a complete technological upgrade. Key innovations included a custom waterproof canister for Dynamixel actuators tested up to 30 m depth, a new power and control board with integrated early-leak detection and power monitoring, and a full migration to the ROS 2 framework for improved modularity and interoperability. These developments resulted in the Open Toolkit for Underwater Robotics, a modular open-hardware and open-software platform providing reproducible, affordable solutions for underwater robotic research.

In parallel, two open-source simulation environments—silver2_gz and silver2_stonefish—were created to accurately model legged underwater locomotion and hydrodynamics. These platforms enable testing and reinforcement learning of control strategies in realistic conditions and are now used by other researchers for multi-agent and environment-aware navigation studies.

BluE also demonstrated the integration of a mobile crawler with the OBSEA cabled observatory, achieving autonomous visual census of benthic habitats and validating the feasibility of extending fixed observatories with mobile robotic platforms. This represents a significant step toward long-term, low-disturbance ecological monitoring.

The project’s scientific results were disseminated through publications in leading journals and presentations at major conferences, establishing BluE as a reference for open, sustainable, and reproducible research in underwater legged robotics and its applications to marine science.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The BluE project delivered the first open and modular technological ecosystem dedicated to Underwater Legged Robotics (ULR), positioning Europe at the forefront of this emerging field. The project’s main outcome, the Open Toolkit for Underwater Robotics, integrates mechanical, electronic, and software designs under open licenses, enabling rapid prototyping, reproducibility, and collaborative development. This open platform significantly lowers the entry barrier for marine robotics research and education, fostering innovation across academia and industry.

BluE also achieved a major advance in simulation by releasing silver2_gz and silver2_stonefish, the first publicly available environments capable of modeling legged locomotion and hydrodynamics underwater. These tools bridge the gap between simulation and field experimentation, supporting the development of reinforcement learning–based control and cooperative autonomy for multi-robot missions.

At the application level, BluE demonstrated a new concept of mobile–fixed observatory integration, combining a crawler robot with the OBSEA cabled observatory for autonomous visual monitoring of the seafloor. This approach enhances spatial coverage and data continuity in benthic ecosystems, providing a foundation for future contributions to the Digital Twin of the Ocean initiative.

To ensure further uptake, next steps include long-term field demonstrations, scaling the open toolkit to new robot platforms, and integrating AI-based decision-making for extended autonomy. The open dissemination of results, together with active collaboration in European initiatives such as MERLIN, SUN-BIO, and DIGI4ECO, will accelerate adoption, standardization, and sustainable exploitation of BluE technologies across scientific, industrial, and policy domains

Logo of the BluE project