Lloyd’s Register, the UK-based ship survey and classification society, has released an Unmanned Marine Systems (UMS) Code for certifying design and build of unmanned vessels.
The LR (Lloyd’s Register) Unmanned Marine Systems Code is designed to provide an assurance process, helping unmanned vessel builders design, build and maintain UMSs against an established framework, achieving a certification level acceptable to Flag States and local regulators.
The Code covers both construction and operation of unmanned vessels, categorising various levels of autonomy a UMS may exercise in specific roles.
“With current and expected developments in autonomous and remote systems LR envisages that, within the near future, UMS will enter into widespread use through many sectors of the maritime industry,” Tim Kent, LR’s Marine and Offshore Technical Director said.
“The Code has been developed against a hazard analysis of UMS design and operation and benchmarked against existing commercial and naval regulatory requirements, including SOLAS (Safety Of Life At Sea convention) and the Naval Ship Code, using LR's depth of experience in these sectors and in the development of goal-based standards. It has been validated against several existing UMS designs.
“The Code has been written to support innovation by establishing requirements for which compliance can be demonstrated using a tailored combination of standards, or where standards do not exist, the application of risk-based assessment techniques.
“Whilst initially targeted at small non-convention sized UMS, including naval systems, it is scalable and is capable of application to larger, more complex vessels as technology and regulation develops.”
The design and control of small autonomous vessels is complicated by issues of seakeeping and navigation not experienced by ships, as detailed in the report “Autonomous Sea-Keeping for USV”, a collaboration between Saab Australia and Defence, Science and Technology (DST) Group in May this year.
“Small boats routinely experience accelerations and moments that large vessels encounter only in the most violent conditions, and they are more likely to operate in environments [littoral] where the wave environment is complex and difficult to predict,” stated the report.
At the Australian Association of Unmanned Systems conference held as part of the Pacific Maritime Exposition 2017 in Sydney in early October, the head of Saab’s Centre of Excellence in Autonomous Vessels, Professor Dr. Derek Rogers, welcomed the creation of an international standard, describing how a vessel’s design and seakeeping capability were the cornerstones of its ability to perform as a safe, effective autonomous platform.
He detailed a four-step level of autonomy, from basic seakeeping through collision avoidance, mission adaptation and cooperative operation, but said seakeeping must remain a priority in autonomous control law design.
“Most USV autonomy research focusses on collision detection and avoidance,” Rogers said in his presentation. “However for collision detection and avoidance to be successful relies on the sea-keeping ability of the vessel. In some cases, the solution that a collision detection and avoidance algorithm provides could endanger the vessel (e.g. pitch-poling or broaching). Sea keeping should thus take precedence over collision avoidance in terms of decision making.
“Likewise collision avoidance takes precedence over mission adaption, which takes precedence over cooperative operation.”