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3 June/July 2023 | Contents Uncrewed Systems Technology | June/July 2023 24 20 46 108 62 04 Intro Many assumed it would be decades before uncrewed systems were widely deployed, but it is already happening at pace 06Platformone: Mission-critical info NASA’s Mars Helicopter smashes its expected service life, Greenjets unveils low-noise electric fan motor, researchers develop ‘ethical’ risk algorithm for vehicles, and much more 20 In conversation: Dr David Barrett How copying nature allows this marine robotics expert to replicate the way large fish propel themselves 24Special review: 50 issues and counting We look back at the milestone trends in uncrewed systems since our first issue, and wonder what the future might bring 36Focus: Additivemanufacturing We catch up on the latest advances in AMmethods, materials and the new applications they are making possible 46Digest: Addverb Dynamo 1T The thinking that went into developing this tonne-capable UGV for automating the handling of stock in warehouses 52 In operation: Skyfish M6 andM4 The methods and technologies behind these bespoke UAVs for inspecting the condition of structures such as cell towers 62 Insight: USVs The latest developments in USVs show a growing trend towards using them for specialised and complex missions 70Show report: Xponential 2023 part 1 Uncrewed systems developers continue to push the limits of their products, as we found among the halls at this year’s event 82Dossier: Electric Flytrain EFT-Hybrid-1x A team of former automotive engineers have migrated to the uncrewed systems market, and developed this hybrid-electric power unit for manufacturers of heavy-lift UAVs 92Focus: Fuel systems The approaches fuel systems suppliers are taking to addressing the efficiency and emissions challenges of UAV IC engines 102Show report: Ocean Business 2023 Our highlights of the new products unveiled at this marine systems show, where autonomous solutions were to the fore 108 In operation: Armach Robotics HSR How this marine robot, and the service it provides, keeps ships running efficiently by clearing their hulls of bio-fouling 114PS: Modular vehicles Sounds great in theory but modularity needs standardised vehicle interfaces and comes with overheads of its own
ELECTRIC,HYBRID& INTERNALCOMBUSTION forPERFORMANCE NASCARatthecrossroads ThepushrodV8quandary Electricracepropellant Batterycell technology Stirring an IndyCar giant The ’80sconquerer revived ISSUE146 APRIL/MAY2023 www.highpowermedia.com UK£15,US/CN$25,EUROPEe22 THE COMMUNICATIONS HUB OF THE ELECTRIFIED POWERTRAIN Cases inpoint Testingtimes Focuson thegrowing range ofbatterycasematerials Thenewdemandsplacedonmaking sureEVpowertrainspassmuster Platform player WAE’sdevelopmentof itsEVRskateboard forelectricsupercars Readallback issuesandexclusiveonline-only contentat www.emobility-engineering.com ISSUE019 | MAY/JUNE2023 UK£15 USA$30 EUROPE€22 4 June/July 2023 | Uncrewed Systems Technology Intro | June/July 2023 This is the 50th issue of Uncrewed Systems Technology, and marks a key point in the evolution of autonomous systems. Many conversations over the years have been based on the assumption that it will be decades before the technology is widely deployed, but already there are selfdriving cars on streets around the world offering commercial services to paying passengers. That is a huge step. At the same time, autonomous technologies are essential for exploring the surface or Mars, both on the ground and in the air, with the Ingenuity helicopter exceeding its design life by a factor of 40 and still going (see page 6). Autonomous systems are also exploring the depths of the oceans, and new technologies are constantly being explored to help them last longer and dive deeper, as we highlight in our report on the Ocean Business show (page 102). The next phase will see the autonomous ‘base station in the sky’ with the latest solar-powered platforms and new technologies for UAVs and VTOL air taxis. Some say it will be many years before we see those systems in our skies, but companies such as Greenjets (page 6) are tapping into motorsport expertise to produce innovative, scalable designs, meaning we will see those systems in the air long before our 100th issue. Nick Flaherty | Technology Editor The future is here Editorial Director Ian Bamsey Deputy Editor Rory Jackson Technology Editor Nick Flaherty Production Editor Guy Richards Contributor Peter Donaldson Technical Consultants Paul Weighell Ian Williams-Wynn Dr Donough Wilson Prof James Scanlan Design Andrew Metcalfe andrew@highpowermedia.com UST Ad Sales Please direct all enquiries to Simon Moss simon@ust-media.com Subscriptions Frankie Robins frankie@ust-media.com Publishing Director Simon Moss simon@ust-media.com General Manager Chris Perry The USE network Having now provided several enterprises around the world with the support and connections they need to implement efficient and sustainable technological solutions, we’re keen to continue expanding this free service. If the uncrewed vehicle and/or system you’re working on could benefit from some independent advice, from engineers specialising in the appropriate field, then please do get in touch. Email your question/challenge/dilemma/predicament to thenetwork@uncrewedsystemsengineering.comor visit www.uncrewedsystemsengineering.comand raise a case with us. All questions will be treated in the strictest confidence, and there’s no obligation whatsoever to follow any recommendations made. Volume Nine | Issue Four June/July 2023 High Power Media Limited Whitfield House, Cheddar Road, Wedmore, Somerset, BS28 4EJ, England Tel: +44 (0)1934 713957 www.highpowermedia.com ISSN 2753-6513 Printed in Great Britain ©High Power Media All rights reserved. Reproduction (in whole or in part) of any article or illustration without the written permission of the publisher is strictly prohibited. While care is taken to ensure the accuracy of information herein, the publisher can accept no liability for errors or omissions. Nor can responsibility be accepted for the content of any advertisement. SUBSCRIPTIONS Subscriptions are available from High Power Media at the address above or directly from our website. Overseas copies are sent via air mail. 1 year subscription – 15% discount: UK – £75; Europe – £90 USA – £93.75; ROW – £97.50 2 year subscription – 25% discount: UK – £135; Europe – £162 USA – £168.75; ROW – £175.50 Make cheques payable to High Power Media. Visa, Mastercard, Amex and UK Maestro accepted. Quote card number and expiry date (also issue/start date for Maestro) ALSO FROMHPM
UXV Technologies A breakthrough in robotic control The brand new SRoC SRM compatible Ruggedized 25 different inputs The SRoC is a standardized product built for defence robotics. It offers high communication flexibility by interfacing through our new Swappable Radio Modules (SRM) and/or the Nett Warrior connector. www.uxvtechnologies.com UXV Technologies, Inc.
6 June/July 2023 | Uncrewed Systems Technology Mission-critical info for uncrewed systems professionals Platformone NASA’s Ingenuity Mars Helicopter has completed its 50th flight on the Red Planet (writes Nick Flaherty). The craft was intended as a technology demonstrator using smartphone components that would fly only five times after landing with the Perseverance rover 2 years ago. It has now flown for more than 89 minutes and more than 7.1 miles (11.6 km). Since leaving the relatively flat confines of Jezero Crater’s floor on 19 January, Ingenuity has flown 11 times, setting a new speed record of 6.5 m/s. Each flight covers new ground, and the images from the helicopter have shown how an uncrewed aircraft could serve as a forward scout for future planetary expeditions. By testing the helicopter’s limits, engineers are gathering flight data that can be used by those working on designs for possible future Mars helicopters. This includes multiple sample recovery helicopters for the proposed Mars Sample Return project. The Martian winter and regional dust storms can block the helicopter’s photovoltaic panel, so the base station on Perseverance needs to search for the rotorcraft’s signal each morning at the time Ingenuity is predicted to wake up. When the helicopter does fly, it has to navigate over rugged and uncharted terrain, landing in spots that can be surrounded by hazards. “We’re flying over the dried-up remnants of an ancient river that is filled with sand dunes, boulders and rocks, and surrounded by hills that could have us for lunch,” said Josh Anderson, Ingenuity operations lead at NASA’s Jet Propulsion Laboratory (JPL). “And while we recently upgraded the onboard navigation software to help determine safe airfields, every flight is still a white-knuckler.” The engineers plan to fly Ingenuity more often, as the helicopter needs to remain within electronic range of the rover. The rover’s auto navigation capability means it can travel hundreds of metres each day, and the helicopter has to be able to keep up with it. “Ingenuity relies on Perseverance to act as a comms relay between it and the mission controllers here at JPL,” said Anderson. “If the rover gets too far ahead or disappears behind a hill, we could lose comms, so it’s imperative that Ingenuity keeps up and is in the lead whenever possible.” Space vehicles Mars ’copter reaches 50 Ingenuity is now 23 Earth months beyond its expected lifetime
7 Platformone Uncrewed Systems Technology | June/July 2023 Nokia has developed the first UAV with 5G connectivity that is CE-certified for industrial operations (writes Nick Flaherty). The ‘UAV in a box’ includes 4G and 5G connectivity with a dual gimbal camera, docking station and edge data processing. An open API allows integration of third-party applications for customisation. Nokia worked with Protolabs to develop the parts for the UAV using injection moulding: they are pressed, packed and shipped to Nokia for assembly. The components have tomeet all the flammability standards for CE approval and stand up to the requirements of outdoor use with fluctuating temperatures, precipitation and UV radiation. The precise choice of material for the designwas key. A fewweeks into the venture, despite the fact that tooling at Protolabs had already begun, Nokia had to abandon its first choice of material because it did not meet the certification standards and the precise needs of the design. Nokia and Protolabs would not comment on the exact choice of material. “Our selection process took on two phases,” said Thomas Eder, head of embedded wireless solutions at Nokia Enterprise Solutions. “In the first, since therewere no qualifyingmaterials, we looked at materials typically used in the automotive sector that alsomeet aviation standards. Then, in the second phase, wematched thematerial against Protolabs’ machining capabilities.” The collaboration required 19 different part designs, for both the casing and the structural aspects of the UAV, as well as for one gasket. “The material not only had to meet aviation safety and outdoor use certification standards, it had to allow the UAV to perform as a 5G device with connectivity,” said Eder. “In addition to the strict requirements for certification, the material also had to performwell in a mechanically challenging environment, where heavy vibrations and shocks are present. Aerial solutions also require the parts to be as lightweight as possible, which means thin walls that create challenges in the moulding pressure,” he said. “From a manufacturing perspective the initial material presented no particular challenge in terms of press capability,” said Dom Corpuz, the Protolabs application engineer who led the project. “But the material that was ultimately selected by Nokia, after flow simulations were conducted, showed it would potentially encounter filling issues when the parts were moulded. “This challenge was overcome by collaboration between us and the team at Nokia, where we discussed part design changes, tooling configurations and the pressure needed to ensure an effective flow of material into the mould cavity.” The dual gimbal payload has integrated HD RGB and thermal cameras. The UAV can also be equipped with other payloads such as loudspeakers, searchlights or customisable sensors for smoke, motion, radiation and more, by using the Nokia payload development kit. Using cellular connectivity also offers higher data rates and lower latency than wi-fi, and supports BVLOS operations with real-time kinetic positioning for more accurate positioning. Dual modems connect simultaneously to multiple networks, complying with the system redundancy capability that is commonly required by aviation regulatory bodies. The UAV can be operated remotely for search & rescue and to assess damage in a hazardous environment, but it can also be programmed to manage autonomous scheduled flights for applications such as additional security at large events or to manage remote equipment inspections. Airborne vehicles CE-certified 5GUAV Nokia’s 5G-connected UAV uses materials from motorsport that meet aviation standards
8 Skydweller Aero has completed the first autonomous flight of its solar-powered aircraft (writes Nick Flaherty). The design, based on the Solar Impulse 2 solar aircraft, uses a new, proprietary fly-by-wire (FBW) actuation control systemwith redundant systems to replace the existing pilot controls. A series of flight tests showed the initial validation of the aircraft’smechanical transformation froma piloted vehicle to a redundant FBWsystemflown from take-off to landingwithout any pilot input. The systemdemonstrates the basis and airworthiness approval for the high-reliability redundant flight control architecture. Multiple levels of redundancy in the autonomous vehicle management systemwill enable the aircraft to operate for many months, using 2 kW from the solar cells on the wings to charge the batteries that power the electric motors. The cells have been updated from those on the original Solar Impulse 2. “Our approach and speed of execution is based on our team’s collective experience of designing and developing advanced autonomous platforms,” said Skydweller’s CEO Dr Robert Miller. “Given the proven history of the airframe and this validation of our successful transformation from a piloted aircraft to an autonomous platform, Skydweller is prepared to demonstrate the aircraft’s operational utility.” Skydweller is now testing the payloads for its first fully autonomous flight. The payload, of up to 300 kg, includes options for a comms relay, 4G/5G cellular, day/night full-motion video, satcom and imaging radar. Airborne vehicles Solar UAVflies bywire June/July 2023 | Uncrewed Systems Technology Skydweller can carry a payload of up to 300 kg, including a range of comms options and radar Platformone
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10 June/July 2023 | Uncrewed Systems Technology A UK company has developed an electric ducted fan (EDF) motor with a specialist blade geometry for low-noise UAV operation while maintaining high efficiency (writes Nick Flaherty). Greenjets is a spin-off of consultancy Blue Bear Systems Research, and is part of a UK project called InCEPTion to develop a quiet electric motor for large aircraft. It is developing a range of motors based on a scalable architecture that is optimised for customisation. The first is a small EDF, the IPM5, which has an outer diameter of 200 mm and weighs 0.75 kg with 5 kgf of thrust using a commercial motor. The ducted design provides more energy efficiency than a rotor-based design, and the company is also developing an integrated inverter and battery pack to further improve the end-to-end efficiency. The motor can also be used with a hydrogen fuel cell or a hybrid gasoline engine that uses a generator to provide the electrical power. This is already being used by one utility customer for a monitoring UAV that can fly for up to 20 hours over urban areas. The ducted propulsor also avoids safety problems with the parachute that the aerodynamics of the EDF to the characteristics of the power supply.” “The ducted architecture enables us to harvest the heat generated by the engine’s internal components to boost the overall system efficiency,” said Dr Guido Monterzino, CTO and co-founder of Greenjets. “The net effect of this is that a portion of the heat rejection turns into thrust.” The company plans to make 500 of the IPM5 propulsors by the end of this year, using suppliers from the motorsport industry, and already has 2000 on order. It has been tested in flight trials on multiple Blue Bear airframes and on an eVTOL in Germany. “We are not doing the manufacturing in-house but we are doing some of the assembly and all the functional testing and QMS inspection on each unit,” said Manohar. “We have a range of partners [from the motorsport industry] for the composites, motors, inverters and other components, and one of them has taken on the assembly line while we still do the final sign-off.” The initial IPM5 is designed for fixedwing and hybrid platforms, but the company is developing a derivative model for multi-rotor designs. Airborne vehicles Low-noise ductedmotor is required for flying over urban areas. The company is also working on a 50 kgf thrust version, the IPM50, that weighs about 8 kg, for larger uncrewed aircraft. The modular design can be modified to provide 20-80 kgf of thrust with scalable components and accordingly different all-up weights. The EDF uses a proprietary modular multimotor design for redundancy, and has been designed to easily scale the size yet still use the same tooling. The blades of the ducted fan have been designed using psychoacoustic modelling, which is where their shape is optimised to reduce the particular frequencies that people find annoying. It has been tested in an anechoic chamber by the Salford Acoustics Lab in Manchester, UK, and wind tunnel tested by the Cambridge Whittle Lab, who are partners in the InCEPTion project that still has a year to run. “We use the term electric propulsor rather than electric jet engine, as that describes what we are all about – converting electricity to thrust,” said Anmol Manohar, CEO and cofounder of Greenjets. “The electricity can come from anywhere – battery, fuel cell or generator – and we match The first electric ducted fan fromGreenjets is the IPM5, which produces 5 kgf of thrust
T-Motor T-MOTOR POWER MAKES YOUR EXPLORATION www.tmotor.com Platformone Echodyne’s radar system has been added to a single integrated operating picture (SIOP) platform for monitoring uncrewed systems in the air (writes Nick Flaherty). A collaboration with ANRA Technologies integrates cloud platforms and ground-based solutions for airspace awareness and UAV detection. SIOP systems are increasingly being proposed to monitor airspace for smaller UAVs that do not have ADS-B beacons or wireless identification. The SIOP application provides a single integrated visualisation that detects, locates and tracks both cooperative aircraft with beacons and, more important, non-cooperative aircraft. The Echodyne radar can be used independently or fused with other sensors for a complete and correlated airspace picture of all sizes of uncrewed aircraft in the airspace on a single display. Ensuring safe UAV operations in the presence of other aircraft is key for the mass roll-out of uncrewed systems for medical deliveries and urban mobility. Improved and comprehensive airspace awareness also helps security agencies, law enforcement entities and other government officials to distinguish between cooperative or authorised airspace users from those potentially posing a safety or security risk. This will become vital as the number of UAVs in operation increases in all classes of airspace. “The SIOP is scalable and adaptable to any region worldwide by providing the most accurate information about all airspace participants,” said Amit Ganjoo, CEO of ANRA Technologies. Echodyne uses metamaterials to create an electronic scanning array radar that is more accurate than other radar systems and is also smaller, allowing the SIOP system to be set up wherever it is needed. Echodyne’s EchoGuard CR radar can provide data for up to 20 simultaneous tracks with latitude, longitude, range, velocity, bearing and closing time to detect. It can assess air targets within a 120° azimuth and 80° elevation field of view. A Matrice 600 UAV can be detected at 350 m, while a smaller Phantom 4 UAV can be detected within 225 m. Airborne vehicles SIOP systemadds radar POWER MAKES YOUR EXPLORATION www.tmotor.com
12 Platformone Researchers in Germany have created an algorithm they say can handle the ethical requirements of autonomous vehicles (writes Nick Flaherty). The researchers, at the Technical University of Munich (TUM), developed the algorithm to distribute the levels of risk fairly rather than operating on an either/or principle. The algorithm is based on the ethical risk evaluation defined by an expert panel for the European Commission in 2020. The 20 recommendations in the report include basic principles such as giving priority to road users that would be worst off in an accident and the fair distribution of risk among all road users. The team has tested about 2000 scenarios involving critical situations distributed across various types of streets and regions such as Europe, the US and China. To translate the ethical rules into mathematical calculations, the researchers classified vehicles and people moving in street traffic based on the risk they present to others and on their respective willingness to take risks. A truck for example can cause serious damage to other traffic, while in many scenarios the truck itself will suffer only minor damage. The opposite is true for a bicycle. In the next step, the algorithm doesn’t simply freeze up and abruptly apply its brakes. Yes and No options are replaced by an evaluation containing a large number of choices. “Until now, autonomous vehicles were always faced with an either/or choice when encountering an ethical decision,” said Maximilian Geisslinger, a scientist at the TUM Chair of Automotive Technology. “But street traffic can’t necessarily be divided into clear-cut, black & white situations – the countless grey shades in between have to be considered as well. “Our algorithmweighs up various risks and makes an ethical choice from among thousands of possible behaviours – and it does so in only a fraction of a second.” Franziska Poszler, a scientist at the TUM Chair of Business Ethics, said, “Traditional ethical theorieswere often contemplated to derivemorally permissible decisionsmade by autonomous vehicles. This ultimately led to a dead end, since inmany traffic situations therewas no other alternative than to violate one ethical principle. “In contrast, our framework puts the ethics of risk at the centre. This allows us to take into account probabilities to make more differentiated assessments.” The algorithmhas been validated in simulations and is available as open source code on the GitHub software platform. It is now undergoing real-world testing using a research vehicle called Edgar. Driverless vehicles ‘Ethical’ street risk code June/July 2023 | Uncrewed Systems Technology was told not to exceed a maximum acceptable risk in the various street situations. In addition, the researchers added variables to the calculation that account for responsibility on the part of the traffic participants, for example the responsibility to obey traffic regulations. Previous approaches treated critical situations on a street with only a small number of possible manoeuvres; in unclear cases the vehicle simply stopped and a remote operator took over. The risk assessment integrated in the researchers’ code results in more possible degrees of freedom and with less risk for all. For example, an autonomous vehicle wants to overtake a bicycle while a truck is approaching in the oncoming lane. All the existing data on the surroundings and the individual participants are now used. The algorithm considers whether the bicycle can be overtaken without the truck moving over to the oncoming traffic lane while maintaining a safe distance from the bicycle. What is the risk posed to each vehicle, and what risk do these vehicles constitute to the autonomous vehicle itself? In unclear cases the autonomous vehicle with the new software always waits until the risk to all participants is acceptable. That means aggressive manoeuvres are avoided, while at the same time the autonomous vehicle TUM’s algorithm distributes the levels of risk fairly, rather than using the either/or principle
TDK has developed a high-stability and vibration-tolerant digital MEMS gyroscope for dynamic applications including uncrewed systems (writes Nick Flaherty). The Tronics GYPRO 4300 has a ±300 o/s input measurement range, 200 Hz bandwidth and 1 ms latency with a closed-loop architecture to deliver high linearity and stability in dynamic environments. This is the first in a series of devices using the architecture and can be used with a closed-loop digital accelerometer platform called the AXO300 for an IMU. The architecture gives a typical bias stability of 0.5 o/h (2 o/h maximum) and an ARW (angular randomwalk) of 0.1 o/√h. The closed-loop architecture also provides a vibration rejection of 0.5 o/h/g² under harsh conditions. TheMEMS sensor is housed in a miniature, hermetically sealed ceramic J-lead package. The package includes fully hard-coded electronics with a 24-bit digital SPI interface for integration into inertial navigation systems and IMUs as well as attitude and heading reference systems. Tominimisemechanical cross-coupling in multi-axis applications, the GYPRO 4300 is available in three frequency ranges. The solid-state architecture reduces the number of internal components and systemcomplexity. This gives an MTBF failure rate in excess of 1,000,000 hours, more than 10 times that of existing dynamically tuned gyros and fibre optic gyros with similar performances. Built-in self-testing also allows an initial verification of the sensor’s integrity and a continuous in-operation functionality test. The part measures 12 x 12 x 5 mm and has the same digital interface as TDK’s Tronics AXO300 digital accelerometer, which is also in a ceramic package. This provides easier connection between the two devices on a PCB, with the ceramic packages providing greater temperature stability than plastic packages. An Arduino-based evaluation kit provides built-in testing of functionalities such as output reading and recording, recalibration and digital self-tests. TDK plans to extend the GYPRO 4300 family with improved bias stability, lower ARW and lower in-band noise for precise attitude determination. Navigation RuggedMEMS gyro CONNECT TECHNOLOGY WITH CONFIDENCE / / WWW . H A R W I N . C O M Harwin UAV Uncrewed Systems March 23.indd 1 17/05/2023 14:56
14 Platformone A coil-powered robot fish could make underwater uncrewed systems easier to develop and deploy (writes Nick Flaherty). The robot fish, developed at the University of Bristol in the UK, is fitted with a twisted and coiled polymer (TCP) to drive it forward. The TCP is a lightweight low-cost device that relies on temperature changes to generatemovement, but it has been limited in its speed. A TCP works by contracting like muscles when heated, converting the energy into mechanical motion. It is warmed by Joule heating, where the passing of current through an electrical conductor produces thermal energy and heats up the conductor. Minimising the distance between the TCP on one side of the robot fish and the spring on the other activates the fin at the rear, enabling the robot fish to move faster. The undulating flapping of the rear finwas measured at a frequency of 2Hz, or two waves per second, moving the fish forward at 25.7mm/s. The frequency of the current is the same as the frequency of tail flap. A TCP actuator is designed with light weight, low cost and high energy density, and can be fabricated using a simple process. However, the coiled polymer actuators have low non-resonant actuation frequencies because of the time needed for the heat to be dissipated lines, and they contract and provide linear actuation when heated up,” said lead researcher Tsam Lung You from the Department of Engineering Mathematics at Bristol. “However, because of the time needed for heat dissipation during the relaxation phase, this makes them slow. “Our robotic fish swam at the fastest actuation frequency found in a real TCP application and also the highest locomotion speed of a TCP application so far,” he said. The team now plan to expand the scale and develop a knifefish-inspired TCP-driven ribbon fin robot that can swim autonomously. Underwater vehicles Robot fishwith a twist June/July 2023 | Uncrewed Systems Technology during the relaxation phase, limiting the speed to under 0.5 Hz. The antagonistic TCP-spring design comes fromminimising the distance between the TCP and the spring. Although this approach requires greater force than other, simpler, designs, TCP is a strong actuator with enough energy density to drive the fin. This is a new route to raising the actuation frequency of TCPs through thermomechanical design, and shows the possibility of using them at high frequency for underwater robots “TCPs can be made from very easily assessable materials such as fishing Propulsion for the robot fish comes from a twisted and coiled polymer, shown as TCP above and running along the side of the fish, below
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16 Elythor has developed a UAV that can adapt its wing shape to wind conditions and flight position in real time, reducing its energy consumption (writes Nick Flaherty). TheMorpho is part wingedUAV, part quadcopter that can change shape according to the task at hand. The adaptive wings extend theUAV’s flight time and give it greater manoeuvrability, allowing it to fly vertically or horizontally andmaking it suitable for applications such as inspecting high-voltage lines and powerplants. When sitting on its four legs as a ‘tailsitter’, the 1.8 kgMorpho has a streamlined shape that resembles a rocket and allows vertical take-off. This allows it to be deployed in confined spaces, fly to within just a few centimetres of a piece of equipment, and inspect the equipment without bumping into it. Once the inspection is complete, the Morpho can shift its motors and rotate into a horizontal, more aerodynamic position and fly to the next inspection site. If the UAV encounters strong or rapidly changing winds along the way, it will expand or contract its wings as necessary to maintain its trajectory. It can also glide given the right wind conditions. All of that saves time during inspections, and means the UAV can fly for longer. It also allows the Morpho to perform inspections in a wider range of weather conditions. “We calculated that using the Morpho can cut the time and cost of an inspection by an average of 35%,” said Harry Vourtsis, co-founder and CEO of Elythor, a spin-off from research centre EPFL in Switzerland. Once the Morpho reaches the next inspection site, it can fold up its wings and return to a vertical position in order to fly right up to the equipment. “Winged UAVs have the advantage of longer flight times, while quadcopters have better manoeuvrability,” said Vourtsis. “We combined the two and added an adaptative wing system that reduces the power requirement even further.” The Morpho’s wing control system is the result of several years of research at EPFL’s Laboratory of Intelligent Systems, and has been described in a number of scientific articles. The system includes sensors linked to a software program for monitoring wind direction and speed. “The controller automatically selects whether to hold thewings in place or let themmove freelywith thewind, according to the trajectory and effective speed, along with any changes inwind direction,” said NathanMuller, another Elythor co-founder. “Thewings’ surface area can also be adjusted symmetrically or asymmetrically depending onwind direction.” The algorithms for the control system seek not just to optimise the tradeoff between air friction and lift, but also to minimise power use. This takes advantage of wind currents to let the UAV glide or adjust the wings asymmetrically to regulate its yaw. This provides greater stability in heavy winds. “Our design can reduce power use by up to 85% when flying in the vertical position,” said Muller. Airborne vehicles ‘Shape-shifting’ UAV June/July 2023 | Uncrewed Systems Technology Morpho is a part-winged UAV, part quadcopter with adaptive wings to save energy We calculated that using the Morpho can cut the time and cost of an inspection by an average of 35%, and can reduce power use by up to 85%
Platformone UAV Navigation has developed a model-agnostic hardwarein-the-loop (HiL) simulator that can be used with third-party models from other developers (writes Nick Flaherty). Simulation can be the workhorse of UAV development, as it is several orders of magnitude quicker and cheaper than real-life tests. The key to a successful simulation environment is to have models that faithfully represent the behaviours of the system being emulated. However, there are some cases where a parametric model cannot capture all the complexity of the platform, or the system integrator already has a working simulation model and integrating it into a HiL is an unnecessary effort. The model-agnostic hardware-in-the-loop (MAHiL) simulator developed by UAV Navigation, part of Grupo Oesia in Spain, allows developers to use their own simulation models in the UAV Navigation simulator environment. The MAHiL simulator uses the same hardware as the regular UAV Navigation-Grupo Oesia HiL simulator. In a standard HiL, the hardware comprises two separate units, FCC (Flight Control Computer) and SIM (Simulator). The FCC is a fully capable Vector-600, like the one flying the real aircraft. The SIM is dedicated to computing the simulation model and sensor data fusion emulation for the navigation solution. A User Datagram Protocol interface has been developed that allows the HiL to receive sensor data from the external MAHiL simulator at the same rate as from the actual sensors on the Vector-600. On the same interface, the MAHiL reports the control vectors from the Vector-600 board with the actuator commands. Sensor readings are fed into UAV Navigation’s sensor fusion algorithm, generating a navigation solution for the guidance and control laws for the FCC to use, just as the real system does. The MAHiL simulator has been developed to be compatible with MATLAB software and SpeedGoat hardware model-based simulation. Its compatibility has been tested in a real-time environment, proving its suitability for meaningful simulation results while greatly reducing adaptation complexity. One advantage of this set-up is the flexibility the designer has to introduce changes to the platform’s design or its physical simulation model. No interaction with UAV Navigation is required to introduce changes, as this is still developed in its preferred simulation environment. Everything is achieved while retaining the core HiL capability, as Vector-600 logic runs on the same hardware and software versions as in real flight scenarios. Airborne vehicles Own-model simulator Dr DonoughWilson Dr Wilson is innovation lead at aviation, defence, and homeland security innovation consultants, VIVID/futureVision. His defence innovations include the cockpit vision system that protects military aircrew from asymmetric high-energy laser attack. He was first to propose the automatic tracking and satellite download of airliner black box and cockpit voice recorder data in the event of an airliner’s unplanned excursion from its assigned flight level or track. For his ‘outstanding and practical contribution to the safer operation of aircraft’ he was awarded The Sir James Martin Award 2018/19, by the Honourable Company of Air Pilots. Paul Weighell Paul has been involved with electronics, computer design and programming since 1966. He has worked in the real-time and failsafe data acquisition and automation industry using mainframes, minis, micros and cloudbased hardware on applications as diverse as defence, Siberian gas pipeline control, UK nuclear power, robotics, the Thames Barrier, Formula One and automated financial trading systems. IanWilliams-Wynn Ian has been involved with uncrewed and autonomous systems for more than 20 years. He started his career in the military, working with early prototype uncrewed systems and exploiting imagery from a range of systems from global suppliers. He has also been involved in ground-breaking research including novel power and propulsion systems, sensor technologies, communications, avionics and physical platforms. His experience covers a broad spectrum of domains from space, air, maritime and ground, and in both defence and civil applications including, more recently, connected autonomous cars. Professor James Scanlan Professor Scanlan is the director of the Strategic Research Centre in Autonomous Systems at the University of Southampton, in the UK. He also co-directs the Rolls-Royce University Technical Centre in design at Southampton. He has an interest in design research, and in particular how complex systems (especially aerospace systems) can be optimised. More recently, he established a group at Southampton that undertakes research into uncrewed aircraft systems. He produced the world’s first ‘printed aircraft’, the SULSA, which was flown by the Royal Navy in the Antarctic in 2016. He also led the team that developed the ULTRA platform, the largest UK commercial UAV, which has flown BVLOS extensively in the UK. He is a qualified full-size aircraft pilot and also has UAV flight qualifications. Uncrewed Systems Technology’s consultants 17 Uncrewed Systems Technology | June/July 2023
18 Platformone Uncrewed Systems Technology diary June/July 2023 | Uncrewed Systems Technology Energy Drone & Robotics Summit Monday 12 June – Wednesday 14 June Texas, USA www.edrcoalition.com Paris Airshow Monday 19 June – Sunday 25 June Paris, France www.siae.fr/en MOVE Wednesday 21 June – Thursday 22 June London, UK www.terrapinn.com/exhibition/move Japan Drone Monday 26 June – Wednesday 28 June Chiba, Japan www.ssl.japan-drone.com/en_la Drone International Expo Wednesday 26 July – Thursday 27 July New Delhi, India www.droneinternationalexpo.com Future C41SR Thursday 27 July – Thursday 28 July Arlington, USA www.americanconference.com/futurec4isr Commercial UAV Expo Americas Tuesday 5 September – Thursday 7 September Las Vegas, USA www.expouav.com DSEI Tuesday 12 September – Friday 15 September London, UK www.dsei.co.uk DroneX Unmanned SystemsWest Wednesday 20 September – Thursday 21 September San Diego, USA www.americanconference.com/unmanned-systems-west UAV Technology Monday 25 September – Tuesday 26 September London, UK www.smgconferences.com/defence/uk/conference/ UAV-Technology Tuesday 26 September – Wednesday 27 September London, UK www.dronexpo.co.uk UAS Summit & Expo Tuesday 10 October – Wednesday 11 October Grand Forks, USA www.uas.bbiconferences.com Intergeo Tuesday 10 October – Thursday 12 October Berlin, Germany www.intergeo.de Egypt Defence Expo Monday 4 December – Thursday 7 December New Cairo, Egypt www.egyptdefenceexpo.com 2024 UMEX Monday 22 January – Thursday 25 January Abu Dhabi, UAE www.umexabudhabi.ae GeoWeek Sunday 11 February – Tuesday 13 February Denver, USA www.geo-week.com Oceanology International Tuesday 12 March –Thursday 14 March London, UK www.oceanologyinternational.com/london Xponential 2024 Monday 22 April – Thursday 25 April San Diego, USA www.auvsi.org/events/xponential/xponential-2024
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20 Propulsive efficiency under water is one of many areas in which nature has had the advantage of hundreds of millions of years of evolution to hone the design of its creatures. Large pelagic fish such as tuna and sharks, and cetaceans such as whales and dolphins, outperform all human made underwater vehicles that aren’t nuclear powered in terms of speed, range and endurance despite having far less power available to them. Dr David Barrett of Olin College of Engineering, in Massachusetts, has dedicated much of his working life to figuring out how the animals do this and creating robotic vehicles that can replicate their feats. He is perhaps best known for his robotic tuna. “I am a biomimetic roboticist, so I copy nature,” he says. One of his more ambitious aims is to create technology that will allow humanity to understand the ocean well enough to stave off climate breakdown. Seeking warp drive It was as a graduate student at MIT’s Department of Ocean Engineering in the first half of the 1990s that his involvement with robots that move like fish began. Here he met Professor Michael S Triantafyllou, who was interested in the fluid mechanics of Gray’s paradox. “Gray’s paradox is basically that Peter Donaldson talks to this marine robotics expert about what we can learn from nature about efficient underwater propulsion Swimming lessons June/July 2023 | Uncrewed Systems Technology Like tuna and many sharks, Dr Barrett’s robot tuna use thunniform locomotion, in which most sideways movement is in the tail and the region that connects the tail to the main body (Images courtesy of Olin College)
21 fish and dolphins shouldn’t be able to swim as fast as they do,” he explains. Working in the 1930s, British zoologist Lord Gray calculated that a typical dolphin has the muscle to generate about half a horsepower. He found that according to the basic principles of fluid mechanics, that power should enable it to reach just 4 knots, but dolphins can swim at up to 30 knots. “The paradox is that dolphins and tuna have what looks like warp drive for underwater vehicles,” Dr Barrett says. A traditional AUV is a cylinder with a propeller on the back, and is severely limited by drag, which increases with the square of the speed. So most AUVs have speed, range and endurance limitations that restrict them to the continental shelves around the world, if launched from the coast. “Mike’s work at MIT was about how to break the range barrier, so we can explore the ocean, work on fisheries, solve global warming and do all the other things that undersea vehicles could be good at,” Dr Barrett says. “There are three ways to solve this. One is to build much better batteries, another is to make everything nuclear powered – but no nation would risk thousands of nuclear-powered mini-subs drifting around the ocean and washing up on beaches – and the third is to find a way to dramatically increase propulsive efficiency. And so we got into this by trying to solve Gray’s paradox. “In water, Gray’s paradox is like the sound barrier in air. Fish and cetaceans, particularly the large pelagic predators – sharks, tuna, dolphins and killer whales – are doing something that a conventional rigid-hulled vehicle is not doing that lets them have these enormous propulsive efficiencies. We are nowhere near fully solving the problem, but we have been able to drop the drag on a wiggly body down almost to zero,” he says. Wiggly drag reduction Wiggling, it turns out, is central to the natural secret that Prof Triantafyllou’s team figured out, because it plays a role in vortex-shedding in a manner that turns drag into thrust. Dr Barrett explains that the vortices, or ‘vorticity’, forms in the boundary layer between a moving body and the mass of stationary water surrounding it. “At the boundary is a viscid layer that is rolling out vorticity, and the vorticity will pop off the back end of the moving body,” Dr Barrett says. The direction in which the vorticity spins is crucial. In a rigid-hull vehicle moving from left to right in our imagined frame of reference, the vorticity on its port side will spin anticlockwise while that from its starboard side will spin clockwise. They continue to spin when they pop off the back of the vehicle, producing a net flow of water in the direction in which the vehicle is travelling, so that the vessel is effectively pulling the water along behind it. “Flow in this direction is drag, which increases with the square of your speed,” Dr Barrett says. “If you have a wiggly tail you can take the drag vortices fromone side of the body and drop themon the other side. You are turning your drag into thrust.” When a tuna or a shark beats its tail from side to side, each vortex it sheds is flicked to the opposite side of the fish’s line of symmetry, so those that form on the port side are shed to starboard and vice versa, although their direction of spin does not change. This causes them to produce a net water flow in the opposite direction to the fish’s movement, he says, so the fish is effectively pushing the water away behind it. In accordance with Newtonian mechanics, that action Dr David Barrett | In conversation If you have a wiggly tail you can take the drag vortices from one side of the body and drop them on the other side. You are turning your drag into thrust Uncrewed Systems Technology | June/July 2023 The overall shape of the robot tuna, coupled with an understanding of its hydrodynamics, harmonics and control, promise huge range and endurance improvements for AUVs
22 In conversation | Dr David Barrett has an equal and opposite reaction, which is the thrust. In this context, Dr Barrett characterises thrust as negative drag. “I have built bodies that have massive amounts of negative drag,” he says. “Gray’s numbers are something like a 10 or 20to-1 multiplier, and I can get 2 or 3-to-1 here, but even so that means a 100 mile mission range could become 200 or 300 miles with the same battery.” The difference between Gray’s numbers, representing nature’s achievements in drag reduction, and Dr Barrett’s current best means there is a lot more to come. Sensing and harmonics One important source of future improvements is sensing. In common with most fish, sharks and tuna have a pair of lateral lines that run along the sides of the body that form an array of pressure sensors. “They run from the nose to the tail, and they can sense the pressure changes created by the vortices on both sides of the body so that they know when to release them,” he says. The sensors provide feedback to what is effectively a closed-loop tuned harmonic oscillator in fish, which he contrasts with the traditional bruteforce approach to propulsion, explaining that small forces applied in phase are much more energy-efficient. The body of a tuna, for example, has a mechanism that takes advantage of such harmonics. “The back end is a big cantilevered spring that oscillates at the same natural frequency that we need to shed the vortices to get the warp drive,” he says. “If you take a dead shark and tow it behind a boat, the back end will wiggle. Its mechanical design is set up to oscillate at the frequency it needs to propel itself, so it takes it very little energy.” Dr Barrett and his team have built 3D computer models of tuna musculature, starting by cutting several of the fish into half-inch thick sections and photographing them. “The muscles are attached to cartilage and bone in the front, and to a springy elastic tendon at the back. The tendon is very complex and has sub-tendons and muscles in it, and it is basically a variable stiffness spring.” The fish’s control system is decentralised, using a set of ganglia along the spine to run the oscillating motion, he explains. “It is a central pattern generator and, basically, the June/July 2023 | Uncrewed Systems Technology The robot tuna’s tails are segmented, and consist of pairs of linear Lorentz force electric actuators that exploit natural harmonics to minimise energy consumption and help turn drag into thrust Although we are nowhere near as sophisticated as Mother Nature, we are potentially far better than a traditional AUV in duration and speed
brain says ‘Start wiggling’ and the wiggle is generated by computation down among the ganglia and not by the main brain.” Having analysed tuna locomotion, Dr Barrett’s team also had to reproduce it. “With modern materials like titanium and glass-reinforced plastic and carbon fibre, we can replicate a tuna skeleton pretty accurately, and using urethanes and silicones we can recreate the skin and tissue,” he says. “We are using linear Lorentz force actuators to replicate the muscles. Speakers for muscles “With a linear drive Lorenz force actuator you can oscillate it back and forth at very high speeds and extremely high efficiency,” he adds. “The systemwe are using is very similar to the voice coils in microphones and speakers. “The actuators are paired, twitch back and forth to create the oscillation, and are connected by springs to the next pair. We do that for the 12 or 14 ribs in the back end of the fish, and if we oscillate them all at their natural frequencies, we get very efficient drive.” To save more energy, regenerative drive electronics for the ‘speakers’ can reverse the motion with efficiencies of 98-99%, comparable to regenerative braking in an electric car. “Although we are nowhere near as sophisticated as Mother Nature, we are potentially far better than a traditional AUV in terms of efficiency, duration and speed,” he says. “I hope someday to be 20 times better, but it would be arrogant of me to say that we can achieve that in a short time frame.” Environment and aquaculture While gliders achieve great range and endurance, they are limited in speed and manoeuvrability, and fish robots are potentially far more flexible, he argues. “You could drop 100 of them along a transit route across the Atlantic and tell them all to swim due south at the same time,” he says. “That way we could do a transect of the entire ocean at once, and to capture that amount of data would revolutionise our understanding of ocean mechanics.” The same acoustic sensors that allow the robot fish to ‘see’ vortices could also serve as passive sonars, complemented by other acoustic and optical sensors on the head to home in on and identify targets, or to assess the effects of mitigations for environmental issues such as coral reef bleaching. By adding a chemical sensing ‘tongue’ a robot tuna could follow chemical gradients to trace pollutants to their sources, he says. They could also download data from arrays of sensors deployed on the seabed using a megabitclass optical datalink and raise a satcom antenna to beam it back to shore. He also sees a future for fish robots in aquaculture, monitoring the condition of salmon farmed in pens or preparing seagrass beds and, further in the future, potentially herding tuna as they grow in the open ocean and bringing the mature fish in for harvesting. Aquaculture needs a low-cost general-purpose vehicle, an equivalent of a $20,000 tractor, he says. A better world Barrett regards engineering as a powerful disruptive force with tremendous potential for good and evil. “In robotics we struggle with this on a daily basis,” he says. “So my overall philosophy is we should create things that make the world a better place, and I should be training my students to do that,” he says. “Engineering isn’t about making money or about making yourself famous; it’s about legacy and about passing on a better world.” As to his own future, he’s happy where he is. “My job is my hobby and my hobby is my job,” he says. In a few years I’ll probably become a professor emeritus and just keep doing it as long as I can. If I train a lot of young engineers to do it well, maybe they’ll keep me around!” 23 Uncrewed Systems Technology | June/July 2023 Born out on the end of Cape Cod on the east coast of the US in 1956, Dr Barrett grew up close to the water and developed passions for the ocean and building machines, inspired in part by the televised underwater adventures of pioneering French diver, naturalist, naval engineer and filmmaker Jacques Cousteau. He excelled in arts and sciences at school, and loved making things in his railway engineer grandfather’s basement workshop from an early age, along with his brothers. “I built my first robot arm in the 1970s,” he recalls. “I welded a bunch of soup cans together and put electric motors in the joints controlled by a set of switches and potentiometers, and it worked pretty well.” As a student he qualified inmechanical engineering and ocean engineering at universities including theMassachusetts Institute of Technology (MIT). That led to a career that has included senior posts with companies including iRobot andWalt Disney Imagineering, as well as posts with research institutions including the Charles Stark Draper Laboratory, MIT andOlin College, where he is nowProfessor of Mechanical Engineering and Robotics, and Principal Investigator for the Olin Intelligent Vehicle Laboratory. He is also on the boards of several robotics companies in an advisory capacity. Dr David Barrett
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