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.”

Using sound waves to detect deadly diseases

Professor Bruce Drinkwater and acoustic levitator

Professor Bruce Drinkwater and his colleagues in Brazil are using acoustics to detect disease. Their collaboration was one of the six projects shortlisted in the Brazil category for the prestigious 2018 Newton Prize.

Sand fly biting skin
Sand flies transfer the parasites that cause Leishmaniasis
Bruce believes that new technology is the key to tackling the challenges of disease and poverty. He said, “As an engineer, working with the end-users of this technology, this is an area where I can make a difference. Leishmaniasis is a tropical disease that’s endemic in 97 countries. More than a million new cases occur each year world-wide and without early diagnosis, people are at risk of disability and death.  Parasites, transferred by sand-fly bites, cause ulcers of the skin, mouth and nose with skin lesions resembling leprosy. Unchecked, infections can be life-limiting, leading to horrific disfigurement, fever, loss of red blood cells and an enlarged spleen and liver.”  

Bruce is working with Professor Glauber Silva from the Federal University of Alagoas in Brazil.

Regular communication is crucial in this interdisciplinary project. Here Professors Silva and Moreira in Brazil discuss the experimental results of a new diagnostic device in a video link to Professor Drinkwater in the UK.
The team have made some fantastic breakthroughs in the area of disease detection: “We are developing small and robust prototype acoustic devices that have the potential to detect Leishmaniasis. The lab-on-a-chip devices use acoustic forces to sort and sense thousands of cells, or other microscopic objects, simultaneously. In Leishmania, the infected cells (macrophages) have different mechanical properties from healthy cells. We can exploit this difference in various ways, sorting diseased from healthy cells is just one. The devices can also help detect antibodies in blood and antigens in urine samples by concentrating them with ultrasonic forces. This leads to more rapid diagnosis and monitoring of the disease.

If successful, theses devices could have a huge impact on the lives of those in Brazil and other developing countries: “Leishmaniasis  is one of the NTDs that lag far behind HIV/AIDS, tuberculosis and malaria when it comes to research funding. It affects 20,000 people each year in parts of Brazil where poverty, overcrowding and inadequate sanitation are major risk factors. If we can have an impact on Leishmaniasis, the same techniques could be used against other NTDs, transforming outcomes for some of the world’s most disadvantaged people. “

If we can have an impact on Leishmaniasis, the same techniques could be used against other neglected tropical diseases, transforming outcomes for some of the world’s most disadvantaged people.

“These devices are undergoing testing by Brazilian biomedical researchers working on neglected tropical diseases (NTDs) with promising results. After further development of the devices, the next phase will be field trials in hard to access areas where help is most needed.

More information

Newton Fund:
The Newton Fund was launched in 2014 to promote economic development in countries eligible for official development assistance (ODA). A grant from the Newton fund and the Royal Society made possible Bruce’s research partnership with Professor Glauber Silva from the Federal University of Alagoas in Brazil, enabling them to bring together a multidisciplinary team with expertise in engineering, physics and biomedicine.

https://www.newtonfund.ac.uk

https://en.wikipedia.org/wiki/Leishmaniasis  (Content note: graphic images depicting disease)