A systematic projection of the future of UUSs S P Way 1 , G R - - PDF document

UDT 2020 UDT Extended Abstract Template Unmanned, Remotely Piloted & Autonomous Systems

A systematic projection of the future of UUSs

S P Way 1, G R Tapsfield 2, S Summers 3 and A C Baker 4

1Stephen Way, Frazer-Nash Consultancy, Bristol, UK, s.way@fnc.co.uk 2 Gavin Tapsfield, Frazer-Nash Consultancy, Bristol, UK, g.tapsfield@fnc.co.uk 3 Sam Summers, Defence Science and Technology Laboratory, Salisbury, UK, stsummers@dstl.gov.uk 4 Adrian Baker, Defence Science and Technology Laboratory, Salisbury, UK, acbaker@dstl.gov.uk

Abstract — As the world becomes more aware of the opportunities and issues posed by Unmanned Air Systems, the question arises as to what the impact of other unmanned systems are. Frazer-Nash Consultancy on behalf of the UK Defence Science and Technology Laboratory (Dstl) has taken an independent view of Unmanned Underwater Systems (UUS), both now and up to 20 years in the future. We have developed an evidence-based projection of the capability

• f UUSs through a structured and systematic approach considering the functional decomposition into subsystems of:

sensing, energy, processing, navigation, communication, propulsion, artificial intelligence, manipulation, launch and

• recovery. Nearly 70 technologies were considered for their impact including biological fuel cells, new battery

technologies, quantum processing and sensing, soft robotics and self-healing systems. Utilising information in the public domain and engaging with UUS stakeholders, we have isolated trends in technology maturity and performance to understand historic developments. We have then projected these into the future, considering if fundamental physical limits will be reached or how development in nanotechnology, biotechnology and novel materials will affect

• development. These projections show the high-likelihood development in capability which we would expect to see. To

capture the potential of disruptive technology breakthroughs, we also considered low-likelihood, high-impact developments, to ensure that the projections were not impeded by a lack of imagination. In summary, the results consider the rate of change of development in subsystems as well as disruptive application opportunities. The results show that a significant number of technologies are technically feasible within the next 2-5 years, but that it is likely to be much longer before they are commercially available. The greatest areas of growth are in sensing and processing. We have developed artist’s impressions of potential UUS concepts applying new technologies arising over 3 epochs of time: 2-5 years, 5-10 years and 10-20 years.

1 Introduction and Purpose

While unmanned air systems (drones) have been widely discussed in the media they cover only one domain of interest for autonomous systems. Unmanned Underwater Systems (UUSs) are also developing rapidly in both their capability and their prevalence, including a growing number of commercially available systems. Developments in a wide range of technological areas are likely to contribute to continued growth in their capability. This has implications for how the UK Ministry of Defence (MOD) should procure, develop and manage capability into the

• future. Such developments also have implications for the

level of threat that UUSs pose and what strategy is used to counter their malicious use. The aim of this project is to inform assessments of the risks and opportunities UUSs provide by:

• Understanding the current state of the art of UUS

capability (covering remote, automated and autonomous systems) including the historic trends in development;

• Appraising the future direction of science and

technology associated with UUSs and their potential capability in the future. This project has been led by Frazer-Nash Consultancy (Frazer-Nash) and supported by the National Oceanography Centre (NOC).

2 Approach and Scope

2.1 State of the Art and Historic Trends Understanding the state of the art for UUSs requires a high-level understanding across a vast range of specialised domains, each of which has been pursued in considerable detail over decades if not centuries. In order to develop and present this understanding we have taken the approach of:

• Decomposing

UUSs into their component subsystems;

• Developing a list of prioritised technologies that

can contribute to these subsystems, both now and in the future, through review of open source data as well as engagement with:

• Frazer-Nash subsystem and technology scanning

Subject Matter Experts (SMEs);

• Frazer-Nash and NOC underwater technology

SMEs;

• Dstl technical representatives.
• Developing Technology Capture Sheets that

capture the state of the art and historic trends for the technologies using information from SMEs and a public domain literature review.

UDT 2020 UDT Extended Abstract Template Presentation/Panel

• Aggregating Technology Capture Sheet results to

illustrate current and historic subsystem capability as well as barriers to further development. 2.2 Future Projections Predicting the future is inherently a high uncertainty task due a lack of available evidence. To provide a prediction whilst mitigating this uncertainty we have taken the following approach:

• For mature technologies, we have extrapolated the

historic for performance with time.

• For immature technologies, we have suggested a

timeline to reach Technology Readiness Level 9.

• Technologies have been reviewed to identify where

future technological development may result in a fundamental performance limit being reached.

• For

those technologies where fundamental performance limits exist, and which have an impact

• n capability, these have been researched and

reported on from open source data.

• Three

key scientific themes including biotechnology, nanotechnology and novel materials have been discussed as to how they might influence the rate of development of technologies.

• The predicted future trends of performance,

maturity and scientific themes have been combined to consider what the capability trend in each subsystem is individually, as well as if all subsystems improve.

• Finally, we have considered the implications of

technology developments that are low-likelihood but high-impact. 2.3 Scope The scope of this work was limited to considering and referencing open source information to ensure the results can be shared in the public domain. Signature mitigation and weapon technology was not to be considered. The focus of the project was performance and capability of systems, as opposed to cost.

3 Summary of Results

3.1 Key Constraints Key constraints in the development of a UUS are:

• Energy: The amount of energy available limits the

power available to other subsystems such as propulsion, sensors etc and also limits the UUS range and operating time.

• Communication:

Remote-control without tethering is unfeasible if operating at depth due to the attenuation of electromagnetic radiation in

• water. This drives the need for autonomous
• systems. It also means that UUSs have to surface to

achieve significant data rates.

• Reliability: Autonomous systems need to either be

reliable or to be able to respond to system failures. Recovery of a failed unmanned system in the ocean is much harder than recovering one on land. 3.2 State of the Art and historic Trends In general, capability is improving across subsystems driven by improvements in energy storage, efficient processors, advanced communication, more capable communications and sensors developments in particular. A key result of this is the growing affordability of highly capable UUS, placing them within reach of the general public. The capability of a UUS is strongly driven by the design requirements placed on it, and requires a trade-off

• f many factors looking at the mission needs and the

demands of the various subsystems. Through this study, we have found that key boundaries include scientific understanding as well as technologies being immature due to them not providing sufficient advantage at this time. 3.2.1 Energy UUSs generally utilise on board battery storage using lithium chemistry based batteries. These can include both primary (not rechargeable) and secondary (rechargeable) cells, where primary cells are likely to have higher energy densities for the same mass/volume. There is limited use

• f

energy scavenging

• r

fuelled generation (hydrogen/nuclear). The key trend has been gradually increasing energy density, leading to increased energy available. 3.2.2 Propulsion The current technologies widely used for UUS propulsion are either electric motors combined with propellers, or alternatively the use of buoyancy drives and glider body

• forms. The selection of propulsion method depends on the

trade-off between the UUS’s speed and persistence. Both approaches are quite mature, therefore the key trend has been in the maturation of alternative biomimetic and multi- modal approaches. 3.2.3 Manipulators The manipulation capability is mainly confined to Remotely Operated Vehicles (ROVs) due to the requirement for additional power and the ability to be remote controlled. Manipulators typically have around 3 rigid links that are hydraulically actuated and use a wide variety of specialised end effectors, including grasping manipulators and tooling. As such they are capable of providing high forces/torques but they are not very dextrous and they are selected for a specific purpose. Electric actuation is available but this is mostly used on research vehicles where the lower force/torques are acceptable and the emphasis is on precision and cost effective maintenance. Key trends are increasing power density of electrical actuators and the maturation of alternative manipulator technologies such as hyper- redundant and soft manipulators.

UDT 2020 UDT Extended Abstract Template Presentation/Panel 3.2.4 Sensors Optical cameras are the most common technology for gaining situational awareness for control and feature on most UUSs. Common sensors for performing missions include acoustic sensors (e.g. Synthetic Aperture Sonar (SAS), side scan sonar and Multi-beam Echo Sounders (MBES)), chemical sensors and sophisticated electromagnetic systems such as lidar. Micro Electro- Mechanical System (MEMS) sensors are growing in prevalence reducing the size, weight and power of the

• sensors. The key trends include an increasing range of

technology options to perform sensing, greater capability (e.g. accuracy, range, more detection phenomena), reduced size/weight/power and the need to handle ever larger sets of data. 3.2.5 Navigation When on the sea surface, navigation is primarily performed using Global Navigation Satellite Systems (GNSS) however these are not suitable when submerged due to the attenuation of the radio waves used. The current state of the art is the use of dead reckoning, combining inertial navigation systems using variations

• n

accelerometers and gyroscopes with other measurements such as those from Doppler Velocity Loggers (DVL) to correct the estimates of position. Position drifts of around 100m a day can be achieved using this approach. Key trends are the increasing accuracy of dead reckoning systems and a growth in the maturity of geophysical navigation approaches. 3.2.6 Communication Acoustic is the most proven underwater communication technology for UUSs however optical systems (both coherent and incoherent) are now considered as viable

• alternatives. Optical systems provide high bandwidth at

short range which then steeply drop off (up to 10Gbps at up to 10m, but little effectiveness at 100m) while acoustic systems can communicate many kilometres away but with data rates of the order of Kbps. Satellite communication and tethered communication are suitable technologies but they place limitations on the freedom of the UUS. Key historic trends are the maturation of optical systems, development of radio through water systems and the shrinking of acoustic communication technology. 3.2.7 Autonomy and Artificial Intelligence Autonomy is required by the Autonomous Underwater Vehicle (AUV) subset of UUSs due to the difficulties in communication while underwater. Currently, the most mature areas are Artificial Intelligence (AI) techniques for movement and navigation, covering mission planning, fault tolerance, navigation and sensor analysis. In these key areas, UUSs are quite advanced and are able to understand and adapt to changes in the environment, system faults and uncertainty in the data they collect. This is in contrast to air and surface systems where there is a greater focus on perception due to the significant amount

• f data available. The increase in capability arising from

multiple UUSs working in partnership has also led to increases in machine-machine collaboration capability. The key trend is an increase in autonomous capability across applications and a growing demonstration of AI techniques such as deep learning. 3.2.8 Processing There are a variety of options available for UUS processing capability and the processor selected depends

• n the requirements of the system. For those UUSs with

relatively low processing requirements it is possible to utilise embedded processors which have minimal size, weight and power requirements. Should the processing required become more demanding (e.g. for sensor data analysis or navigation), then it is possible to utilise desktop equivalent processing capability, whether that is using multi-core Central Processing Units (CPUs) or Graphics Processing Units (GPUs) which have a higher performance across parallelised tasks but have significant energy requirements. Field-Programmable Gate Arrays (FPGAs) and Application Specific Integrated Circuits (ASICs) can provide lower size, weight and power processing solutions. For dedicated machine learning algorithms there are specialised processors available referred to as Tensor Processing Units (TPUs).The key trends for processing are increasing processing performance, reducing energy requirements, increasing number of units produced and decreasing costs. 3.2.9 Launch and Recovery Current UUS launch and recovery systems cover ramps, nets and crane-like lifting systems which allow for UUSs to be launched and recovered from the side of a boat. These approaches require the relative motion between the boat and the UUS to be managed to prevent collision damage and to allow personnel to correctly locate the UUS in any lifting mechanism. This means that sea state can limit

• perations and vessel speed needs to be carefully
• controlled. A partial exception to this are moonpools

within a vessel which allow for launch and recovery in a more sheltered environment. The disadvantage of these is that they are expensive and that a specialised vessel is

• required. Aerial launch is also available for torpedoes or

sonar buoys in the military domain. Key trends are relatively slow progress to improve the safety of

• perations at higher sea states and higher vessel speeds.

3.2.10 Miscellaneous topics The smallest UUSs available appear to be of the order of 10s of centimetres long. Smaller vehicles may be possible however there appears to be limited use for smaller UUSs

• currently. The key trend in size reduction is linked to the

size reduction of the subsystem components. Self-healing materials are currently being experimented on within laboratories and have not been applied to UUSs. The same is true for modular,

UDT 2020 UDT Extended Abstract Template Presentation/Panel reconfigurable robots, i.e. those with a very adaptable system architecture. Currently these approaches are thought unjustified compared to fault tolerant control and design for system robustness/redundancy. 3.3 Future Projections 3.3.1 Expected Trends The expected trends across systems are outlined in Table 1 below. All capabilities of UUSs are expected to improve allowing UUSs to travel further and faster, carrying larger payloads, manoeuvre more quickly, have a more comprehensive understanding of their environment, have greater levels of autonomy, physically interact with a wider range of objects and co-operate with other unmanned systems. These improvements can allow for less onerous launch and recovery, reduced manning requirements, new ways of interacting with humans and improved performance in challenging environments such as under ice, deep water and the littoral environment. Although improving, the key challenges are likely to remain managing the available energy, limited availability

• f communications and reliability.

A number of the improvements and capabilities identified here could be developed in a relatively short period of time, however it is expected that there will be insufficient interest in funding their development as there is no clear need at this time. 3.3.2 Capability Impact Table 2 summarises the capability impact of developing subsystems, while Table 3 summarises the influence on manning and the operation of UUS in challenging environments. Likely rate of increase in timeframe Subsystem Near term (2 to 5 years) Mid term (5 to 10 years) Long term (10 to 20 years) Energy Steadily Steadily Steadily Propulsion Slightly Slightly Slightly End effectors and actuation Steadily Steadily Steadily Sensors Greatly Greatly Greatly Navigation Steadily Steadily Steadily Communication Steadily Steadily Steadily Autonomy and Artificial Intelligence Steadily Steadily Steadily Level of improvement Subsystem Capability impact summary Greatly Increase Sensors Allow for more comprehensive and rapid understanding of the environment including a greater range, resolution, accuracy and number of physical phenomena detected. Processing Provides improved data analysis, environmental and navigation understanding. Able to run autonomy algorithms which provide greater flexibility in adapting to uncertainty. Steadily Increase Energy Operate more capable subsystems for longer. End effectors Interact with a wider range of objects while reducing the need for specialised tools. Navigation Allow longer periods of time submerged accurately and to have smaller safety margins. Communication Communicate at a higher data rate. Decrease time for data to be actionable when communicated, whether underwater or above water. Autonomy Improved decision making. Greater flexibility in adapting to uncertainty. Faster and deeper understanding of natural and manmade environment. Slightly Increase Propulsion Slightly improved mission endurance and speed. Improved manoeuvrability. Ability to transit over land and through the air.

Table 2. Functional capability impact Table 1. Aggregation of Expected Trends

UDT 2020 UDT Extended Abstract Template Presentation/Panel 3.3 Future Projections Considering the developing technologies and the improvements in existing technologies 3 illustrations of potential, widely available, future systems have been developed over the 2-5 years, 5-10 years and 10-20 years in the future. These are illustrated in Figure 1 – 3, and focus on systems which have significantly different appearances over present day systems. The first system for 2-5 years’ time in Figure 1 adapts a quadruped robot so that the front legs steer while underwater and the rear legs provide propulsion, meaning that the system can traverse land or water. Such a system could use LEDs for communication with nearby assets, low-light cameras, wet chemical sensors for a wide range

• f targets and navigation through observation of

topography.

• Fig. 1. Potential system in 2-5 years’ time

The system for 5 – 10 years’ time in Figure 2 shows a system to be used for maintenance in confined areas. Dual manipulators allow the system to hold onto a fixing while manipulating an object, while the biomimetic tail allows for tighter manoeuvring. Improved processing enables more capable autonomy, so that manipulation is autonomous. Navigation is supported through Simultaneous Localisation And Mapping (SLAM).

• Fig. 2. Potential system in 5-10 years’ time

The next system is thought to be available in 10 – 20 years’ time and features full-body flexible biomimetic propulsion, soft adaptable end effectors utilising contact

• Fig. 3. Potential system in 10-20 years’ time

Subsystem Manning Influence Challenging Environments Sensors More robust and therefore aids handling. Decreases the effort to analyse results. Increases time at depth through increasing efficiency and more data/better analysis improves littoral understanding Processing Enables autonomy – see below. Enables autonomy – see below. Energy Safer energy storage reduces handling effort as less precautions are needed. Can also reduce the effort to recharge. Enables improved sensing under ice as it allows for more capable sensors. Increases operating range at depth. End effectors Increases manning required due to the control needed unless manipulation autonomy is applied. Could help protect UUS in littoral environment and to manoeuvre in enclosed spaces. Navigation Reduced effort to programme missions. Safer operation under ice, lower drift in deep water and increased confidence in littoral environment. Communication Significant change unlikely. Significant change unlikely. Autonomy Increasing autonomy decreases effort to perform low-level operating functions. Shifts effort from a low-level to a higher- level focus. Provides an improved understanding in enclosed and littoral environments. Increased robustness under ice as a greater amount of uncertainty can be accounted for. Propulsion Improved reliability in propulsion decreases maintenance required. Increases efficiency in deep water and provides greater manoeuvrability in littoral/ enclosed environments.

Table 3. Manning and environments capability impact

UDT 2020 UDT Extended Abstract Template Presentation/Panel along the arm, full autonomy, local communication using lasers, more energy efficient processing and significant energy stores. 3.3.2 Low Likelihood, High Impact Changes If there are significant improvements in UUS capability across subsystems then many novel concepts could become feasible. Impacts arising from the extreme improvement of each subsystem are:

• Energy: Increases in performance of all systems

and significant increase in range leading to UUSs deploying from shore.

• Propulsion: Natural movement through the water

and an ability to operate on land and in the air.

• Manipulation: Highly adaptable end effectors

with high force density enabling collection, repair, construction and disassembly underwater.

• Sensors: An ability to detect natural and manmade

phenomena from hundreds of miles away, rendering the ocean essentially transparent.

• Navigation: Understanding of global location with

an accuracy of millimetres after weeks underwater and with denied access to Global Navigation Satellite Systems.

• Communication: Communication of submerged

UUSs with surface, satellites or land assets with little delay allowing remote piloting and instantaneous data analysis.

• Autonomy: Advanced decision making and

improvisation, leading to a high level of understanding, communicating across swarms of UUSs such that they are considered as peers to humans.

• Processing: Enabling advanced autonomy to be

performed, considering a broad range of sensor data and enabling optimisation. Taken together these changes could lead to novel concept such as UUSs as oceanographers, swarms of manipulators, grown UUSs (not manufactured), UUSs operating for thousands of years, swarms produced by amateur makers, assembly and maintenance of ocean dwellings and free- range fish farming. An illustration of one such swarm system is provided in Figure 4 below.

• Fig. 4. Low likelihood, high impact potential system

This image portrays a swarm of smaller systems combined into a single unit, where each small element has its own processing, sensing, propulsion and energy

• capability. When combined together the capability of the

assembled unit increases. Through intra-swarm communication the units can also perform distributed processing. The swarm can reconfigure to meet the needs of its

• peration, or split apart to evade detection and to

manoeuvre through small openings.

4 Conclusions

The results consider the rate of change of development in subsystems as well as disruptive application opportunities. The results show that a significant number of technologies are technically feasible within the next 2-5 years, but that it is likely to be much longer before they are commercially available. The greatest areas of growth are in sensing and processing. We have developed artist’s impressions of potential UUS concepts applying new technologies arising over 3 epochs

• f time: 2-5 years, 5-10 years and 10-20 years.

Acknowledgements

Frazer-Nash Consultancy and Dstl thanks National Oceanography Centre representatives Paul Bell, Terence Wood and Andrea Munafo for their guidance.

Author/Speaker Biographies

Stephen Way is a Technology Management Consultant and the robotics lead at Frazer-Nash Consultancy. A Chartered Mechanical and Systems Engineer, he has 9 years of experience helping clients with the maturation and application of developing technologies working across robotics, submarines, surface vessels, renewable energy, nuclear power and land defence. Gavin Tapsfield is an experienced systems engineer, who specialises in developing novel approaches to understand and visualise complex problems. The majority of his work focuses on defence, including armoured vehicles, electronic warfare, submarines and unmanned systems. His work focuses on identifying emerging technologies, and assessing their risks and opportunities based on their capabilities and maturity.

References

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