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The innovative robotic arm that could transform autonomous marine operations

Submarine Technology Limited (STL) is a consultancy, design, development and ‘one-off’ project implementation group, specialising in the subsea and offshore industries. STL takes innovative technological concepts, develops them to a practical and economically viable state, to create a springboard for commercially successful ventures.  The company has been involved in many leading-edge projects within the marine sector.

During the first phase of the Marine-i project, STL received support and grant funding for the development of a futuristic robotic arm. The innovation is a ship-based multi-axis robotic arm for autonomous operations. It will form an integral part of a new Autonomous Synchronised Stabilised Platform (ASSP) to enable intervention tasks to be carried from Autonomous Surface Vessels (ASV). Typical intervention tasks will include equipment transfer and payload management, survey and inspection, launch and recovery.  In the future, ASVs will play an important role in the inspection, servicing and repair of offshore wind farms and other renewable energy technologies.

The purpose was to develop a “synchronous-stabilisation” capability whereby the motion of the tool-end of a robotic arm can be synchronised with a moving target.  The motion sensing, control system, and construction of a small-scale ASSP arm to demonstrate synchronous stabilisation were successfully achieved.

In 2020, STL and Marine-i agreed to work together again on the next stage of development of the robotic arm. Dr Sanjay Sharma, Associate Professor in Intelligent Autonomous Control Systems at University of Plymouth, explains: 

“The aim of this next stage was to develop a Remote Sensing System to allow STL’s hydraulically actuated robotic systems to achieve ‘Synchronous-Stabilisation’ without the need for data communication between the moving target and the host vessel.  Synchronous-Stabilisation will help improve the reliability, success and safety of ship based tasks such as Launch-and-Recovery and cargo/equipment transfer between two floating platforms or vessels.

“The Remote Sensing System will add Machine Vision to STL’s sophisticated robotic control systems.  This will enable the movement of objects of interest to be tracked relative to a known datum.  Movement data will be fed back into the control system allowing robotic arms to synchronise with the object.  Typical ‘objects of interest’ include Autonomous Underwater Vehicles, Remote Operated Vehicles, and Floating Wind Turbines.”

As well as grant funding, the Marine-i team created a bespoke RD&I programme for STL’s new technology. This programme comprised:

  • Evaluation of object tracking systems
  • Design and build of an object tracking system, together with modifications to the ASSP robotic arm
  • Trials in the Ocean Basin at University of Plymouth COAST Lab
  • Sea trials at the FaBTest site in Falmouth Bay

Peter Back, Technical Director for STL, says:

“We're really grateful to have had the expert support of the Marine-i team in developing our new technology. The structured RD&I programme that they have worked on with us is helping us bring our pioneering innovation to market quicker than might otherwise be possible. It's also fantastic to have access to world-class testing facilities here in the South West to help us refine and test our approach.”

Prof Lars Johanning, Programme Director for Marine-i, says:

“This project by STL is at the cutting-edge of science. The technology underpinning STL’s work on advanced motion compensation and the potential applications for it could have a major impact on activities associated with marine operations, offshore renewable energy, and personnel transfer at sea.  In particular, it should contribute significantly to enabling unmanned or autonomous operations at sea and underwater, with potential cost reduction and improved operational safety benefits. 

“As far as we are aware, there is no directly comparable full system solution with identified innovative functions that is currently available. Our work with STL is helping to put Cornwall at the forefront of developing a new marine technology for the International offshore energy sector, as well as offering functions in a number of other offshore sectors, including oil and gas and aquaculture.”

[Image: STL ASSP Remote Sensing System]