German institute Fraunhofer Centre for Maritime Logistics and Services (CML) is pushing forward the development of maritime innovations by using a modular Autonomous Surface Vehicle to enable applied research[ds_preview]
For almost twelve years, the Fraunhofer Center for Maritime Logistics and Services (CML) has been developing and optimising processes and systems along the maritime supply chain. For the majority of the time, the focus has been on innovation in software solutions and logistics concepts. In recent years, a new area has been developed based on one of the core competencies of the Team Maritime Technologies and Biomimetics – Maritime Robotic Assistance Systems.
Autonomous Surface Vehicles
The developments of the CML are characterised by the Fraunhofer guiding principle of applied research. The first series of trials was launched quickly after the development, and all testing activities are taking place on an experimental prototype for implementing maritime robotic applications. Conducting experiments in applied research is key to making new findings and transferring research to real-world applications. However, running experiments, especially in the maritime field, is often expensive and involves much time and effort. To enable more accessible research and validation of new ideas, the Fraunhofer Centre for Maritime Logistics and Services built an Autonomous Surface Vehicle (ASV) called »SeaML: SeaLion« with a modular design to quickly implement innovative research concepts and test state-of-the-art sensors and service concepts.
SeaLion serves as a flexible test and demonstration platform for various technologies related to maritime robotics. The vessel is purely electrically powered with an overall length of 2.2 m and width of 1.5 m. The ASV features a catamaran design for improved stability while waterborne and a modular layout of the onboard systems. The twin hulls are connected by a superstructure that can accommodate various combinations of sensors and equipment used to perform many experiments.
Up to 24 hours
The unique feature of the ship is the modularity of the equipment that can be installed on its deck. Depending on the research project, a complex structure such as a Launch and Recovery System (LARS) for underwater robots can be installed, or a completely empty deck is possible.
The modular architecture of SeaLion continues within the hulls, where the eight cylindrical compartments display a special design feature. All electronic components are arranged in these units and can be easily removed and replaced depending on the application. The vessel is powered by two 48V batteries (also placed in a compartment per hull) of 2.3 kWh each. This enables a mission duration of up to 24 hours. The battery voltage is converted to 24V, 12V and 5V respectively to power sensors, computers, actuators, and other equipment that can be installed when needed. SeaLion is controlled by a central computer, a small form factor PC (Intel NUC). This pc communicates with several small single-board computers via Ethernet.
Consequently, all domain controllers are connected to the same Local Area Network (LAN). 5GHz connection allows a stable and fast connection between the ship and the shore station. On the software side, the ship is based on the open-source middleware package Robot Operating System (ROS). ROS is a comprehensive set of software frameworks allowing low-level device control and implementation of commonly used functions such as winch control.
»RAPID« project
SeaLion has already been validated through several sea trials in the Port of Hamburg and a public demonstration throughout the Intelligent Transportation Systems (ITS) Congress in 2021. This demonstration shows the robotic service approach developed in the RoboVaaS (Robotiv Vessels as a Service) project (MarTERA co-found project 2017–2020, EUR 2 million, seven partners), which Fraunhofer CML led. The project aims to make maritime operations in ports more efficient and safer by integrating and connecting smaller ASVs (Autonomous Surface Vehicles) and ROVs (Remotely Operated Vehicles) to offer new services to shipping industry. Five service concepts have been developed: Ship hull and quay wall inspections with a combination of ASV and ROV, a real-time anti-grounding service with ASV, depth data acquisition, and data muling – an innovative form of underwater acoustic data transport.
Another project in which the research vessel is currently being used is the RAPID (Risk-aware Autonomous Port Inspection Drones) project. This HORIZON 2020 project develops automated port inspection drones with autonomous beyond visual line of sight (BVLOS) flight and inspection capabilities based on the integration of advanced sensors and onboard data processing and technologies for extended energy autonomy. Fraunhofer CML develops drone control, web-based microservices, remote emission sensing technologies, and a UAV battery hot-swap system (BHS). The BHS makes it possible to replace the batteries of the used DJI M300 flying drone to avoid downtime. The whole BHS system is installed on the deck of SeaLion, allowing the drones to be used in places that are not accessible due to their limited range.
Various tests
The ASV has been put through its paces in various tests since its introduction. These included port surveys, autopilot investigations, and robot-as-a-service studies. Further development of the ASV aims at two aspects: developing autonomous services in the maritime sector and developing an intelligent situational awareness controller. These developments of new controls and algorithms are not only carried out in the real port environment but also in a simulation. Developing a local trajectory planning algorithm for collision avoidance manoeuvres and considering the COLREG rules through surface sensor technology is envisaged soon. In addition, different object detectors trained on real and synthetically generated data sets were trained to detect and identify traffic vessels, and infrastructure elements were tested. After various optimisation cycles, a model for the detection of ships, pontoons or other traffic participants could be created.
Expanding capacities
With SeaML: SeaLion, Team MTB has laid the foundation for demonstrating future maritime robotics concepts. In this way, the CML contributes significantly to improving the innovation of ports and seas. With the move to a new building in Hamburg-Harburg port in 2022, the CML will expand its personnel and research possibilities. With these new possibilities, the team can advance its visionary concept of Maritime Robotic Assistance Systems even faster by making its software solutions more efficient in conjunction with concrete hardware developments. With the implementation of challenging research projects, the CML looks forward to exciting times in which it can act as a reliable partner for industry and as a driving force for the development of future ports.
