Gulliver’s travels: can drones learn from nature?

Unmanned aerial vehicles are rarely out of the headlines. The world’s first driverless passenger drone has already been tested in China, and major companies have begun trialling drone deliveries to customers.

But despite this huge acceleration in popularity there’s a number of challenges which drone manufacturers are facing, not least the matter of urban drone navigation. To investigate this problem, PhD students Cara Williamson and Anouk Spelt are studying urban gulls to understand the most efficient flight paths through urban landscapes. We spoke to Cara to learn more about their project.

Drones could benefit society in so many ways, from the obvious, such as parcel delivery, to the life-changing, such as being the first point of contact for emergency services.

“The Urban Gull Project was started in 2016 by myself and Anouk Spelt as part of our PhD research. We’re supervised by Dr Shane Windsor who won a grant to start the Bio-Inspired Flight Lab.  Over millions of years, nature has optimised for every environment – urban gulls are particularly adept at coping with the complex wind flows around city buildings. UAVs could use similar flight strategies. Drones could benefit society in so many ways, from the obvious, such as parcel delivery, to the life-changing, such as being the first point of contact for emergency services.

Computational model of wind flow over buildings

“The project brings together biology and engineering, using GPS devices on 11 lesser black-backed gulls in Bristol. The tiny backpacks (under 3% of the bird’s weight) track location, altitude, speed and 3D acceleration data which tells us whether the birds are soaring or flapping.  Preliminary research showed how gulls position themselves in updrafts on the windward side of buildings to improve control and mitigate risks from gusts. These wind-highways help them maintain altitude so they can soar for a third of their flight time.  We’re now seeing that gulls choose routes to foraging grounds that save them energy, even if they are twice the shortest distance.

Battery life is a big problem for drones. Batteries are heavy and limit their range and endurance.

“The wind modelling and path planning method I’ve been using is very quick and could be run in advance of a UAV making a delivery, for example, in order to pick a route that keeps energy costs to a minimum. Battery life is a big problem for drones. Batteries are heavy and limit their range and endurance.

Tracking gull flight around Bristol.

“We collect habitat and weather data in and around Bristol. It’s the perfect location as it combines a diverse built environment with an established gull population. Over the last few decades, the birds’ distribution has moved away from traditional seaside haunts. It’s thought that cities offer warmer temperatures, protected nesting sites and rich pickings from our litter. Anouk compares the gulls’ foraging behaviour and energetic costs with their rural cousins to establish what is really going on.  Despite being referred to as seagulls, our birds don’t visit the sea at all during breeding season (March-August), which is why we use the term urban gulls (first coined by our collaborator and South West gull expert of over 30 years, Pete Rock).

Cara and Anouk present their projects.

“Having followed the gulls for three years, we’ve seen a gull laying an egg, held hatching eggs and watched chicks taking their first flight. Our work has taken us to the top of landfills, quarries, the waste treatment centre and up many tall buildings and church spires. The gulls have distinct traits – we even named some of them after our favourite Game of Thrones characters; Arya (quite feisty – tried to peck us); Sansa (the most beautiful); Lady Brienne (the largest) and Tyrion (the smallest). We also got very attached to the first season’s chicks and learnt the hard way that nature can be quite brutal. It would be good to mend the human-gull relationship. We want to get the message out that when animals thrive in the environments we create, they can teach us so much. It’s vital to study and conserve the natural world.

“At the moment, we’ve got a packed programme of workshops in schools. Pupils design and fly drones and find out about bio-inspired engineering and wind pattern modelling.  We’ve had some really encouraging feedback and we hope we’ve inspired a new generation of kids to take STEM subjects that they wouldn’t have previously considered.  We were really pleased that this outreach programme was recognised when the project was shortlisted for the 2018 Airbus Diversity Awards.”

Nine ways our engineers are building a greener world

It’s Green Britain Week this week. While debate rages between environmental campaigners and those wandering the corridors of power, engineers are ever pragmatic and practical. Our researchers are working on a range of technological advances that will reduce the carbon in our atmosphere.

Here’s nine of our projects:

  1. Wind power: Harnessing wind power will be a key component of a greener energy mix. In partnership with Offshore Renewable Energy, the Wind Blade Research Hub is pushing the boundaries of current technology to produce a 13MW turbine. They are working on blades that will be 100m long, requiring new designs, materials and manufacturing processes. The world-leading expertise of the Bristol Composites Institute (ACCIS) is crucial in delivering this and other sustainable structures.
  2. Offshore wind and tidal lagoons: In another initiative to tap into the UK’s potential for offshore wind and tidal energy, a proposed tidal lagoon in Swansea Bay could provide electricity for more than 155,000 homes. It will take a solution that is affordable and scaleable to turn this idea into a reality. Researchers from Bristol and Plymouth Universities are part of a project to design and develop a prototype.
  3. Solar Cells: Solar energy is getting ever-more affordable. A £2 million grant from the EPSRC has funded work to develop new low-cost photo-voltaic materials. Researchers from the Bristol Electrochemistry Group’s PV Team are looking to replace elements such as gallium, indium, cadmium and tellurium which are rare, expensive to extract and toxic.
  4. Electric Vehicles: The move away from petrol/diesel and towards low carbon hybrid/fully electric vehicles depends on the availability of compact, highly efficient engines. The Electrical Energy Management Group are innovating and testing solutions. Their industrial collaboration on high performance electro-mechanical drives is important for the traction, steering and road handling of the cars of the future.
  5. Energy Storage: If the sun is shining and the wind is blowing, how can we store all that free energy? This question is being addressed by researchers from the Universities of Bristol and Surrey as part of self-funded company Superdielectrics Ltd. They have discovered new hydrophilic materials, like those used in contact lenses, that could rival the storage capacity of traditional batteries and charge much faster. Rolls-Royce recently signed a collaboration agreement with Superdielectrics, highlighting the keenness of industry to find new solutions.
  6. Microgrids: Ditching fossil fuels and halting deforestation can’t happen unless there’s a sustainable energy alternative. It’s estimated that 1.2bn people across the world don’t have access to electricity. By working with NGOs, local authorities and residents in rural areas, researchers from the Electrical Energy Management Group are designing a micro-grid system, intended for remote communities. It could generate enough power for 250 homes, using wind, solar and micro-hydro energy. A scaleable modular design means extra units can be added as and when.
  7. Water management: Climate change is having an impact on our water cycle with flood patterns already changing. The way we manage water resources will be increasingly key to mitigate natural disasters and provide clean drinking water to a growing population. The Water and Environmental Engineering group brings together engineers and scientists, taking a multi-disciplinary approach to the complex issues raised through modelling, measuring and prediction.
  8. Nuclear: Although controversial, nuclear energy will be part of the low carbon energy picture for the foreseeable future. The South West Nuclear Hub brings together academics from numerous disciplines. Their research ensures that nuclear systems are safe, reliable and efficient. Also focusing on safety, the department of Civil Engineering has been exploring the seismic integrity of nuclear reactors using the University’s impressive earthquake shaking table. The Plex project was one of the most complex shaking table experiments ever attempted anywhere in the world.
  9. Efficient Aircraft: Aviation is a major contributor to global CO2 emissions, burning more fossil fuels per passenger than any other form of transport. The Advanced Simulation and Modelling of Virtual Systems (ASiMoV) partnership aims to produce a jet engine simulation so accurate that designs can be signed off by the civil aviation authorities pre-production. It is hoped that by modelling the physical effects of thermo-mechanics, electromagnetics and computational fluid dynamics, more cost effective and energy-efficient engines will get off the ground.

Aerospace PhD in Three Minute Thesis final

Three Minute Thesis (3MT®) is an international competition that celebrates exciting research by PhD students around the world. Developed by The University of Queensland (UQ), the competition cultivates students’ academic, presentation, and research communication skills. Presenting in a 3MT competition increases your capacity to effectively explain your research in three minutes, using lay language. Competitors are allowed one PowerPoint slide, but no other resources or props.

This year Andres Rivero from the School of Civil, Aerospace and Mechanical Engineering made it to the Bristol final with his presentation, ‘Flexible airplanes: achieving higher fuel efficiency by adapting wing shapes during flight’.