Nav: Home

Improving drone performance in headwinds

February 08, 2018

Is it a bird? Is it a plane? The prevalence of multi-rotor drones has increased dramatically in recent years, but in headwinds they pitch upwards unpredictably. Engineers from Tohoku University, Japan, have shown that angling the rotor blades of a quad-rotor unmanned aerial vehicles by just 20 degrees can reduce pitching by a quarter. Their work is published in the International Journal of Micro Air Vehicles.

Multi-rotors have gotten much smaller since the turn of the century, and they have many uses, including for inspection, surveillance and transportation. A multi-rotor setup allows for both vertical takeoff and hover in calm conditions, but they are unstable in wind. Their rotors flap and the vehicle pitches upwards in a headwind. In this experiment, Hikaru Otsuka and colleagues set out to evaluate whether angling the rotor blades differently would improve control of quad-rotor vehicles in winds.

Pitching can occur because of three factors: the drag of the body, the asymmetry induced flow distribution on the rotor with the wind, and rotor thrust difference between the front and rear rotors. The team first estimated the effects of the wake of the front rotors on the rear, then isolated the rotors from the vehicle and measured the effect of different angles in a low-speed wind tunnel. They show that angling the rotors to the outer side by 75 degrees kept the airflow passing each rotor blade isolated, but increasing the angle to 90 or above meant the wake of the front rotors affected the rear.

Then they analyzed how this translated to a complete quad-rotor with all four rotors working together. In the wind tunnel, the team tested various angles of rotor attachment to the quadrotor and the effect on pitching moment generation. They measured the effects of outward and inward tilting of the rotor blades for five different angles. They found that rotor tilting by 20 to the outer side degrades the pitch of the vehicle by 26%.

The authors conclude that tilting of the rotors to the outer side reduces pitching moment of quad-rotor vehicles in winds. The work could have implications for both hobbyists and for professionals who want to use multi-rotor unmanned vehicles outdoor, as for inspections of wind turbines, disaster sites, or for safety of rescue activities.
-end-


Tohoku University

Related Wind Tunnel Articles:

Could handheld electronic devices contribute to carpal tunnel syndrome?
In a study of 48 university students, intensive users of electronic devices reported more wrist/hand pain than non-intensive users.
Spintronic technology advances with newly designed magnetic tunnel junctions
Magnetic tunnel junctions (MTJs) have played a central role in spintronic devices, and researchers are working to improve their performance.
Physical therapy proves as effective as surgery for carpal tunnel syndrome
Physical therapy is as effective as surgery in treating carpal tunnel syndrome, according to a new study published in the March 2017 issue of the Journal of Orthopaedic & Sports Physical Therapy® (JOSPT®).
Acupuncture improves outcomes in carpal tunnel syndrome in part by remapping the brain
A team of investigators based at the Athinoula A. Martinos Center for Biomedical Imaging at Massachusetts General Hospital sheds new light on the question of how acupuncture relieves symptoms of carpal tunnel syndrome.
Offshore wind push
Injecting large amounts of offshore wind power into the US electrical grid is manageable, will cut electricity costs, and will reduce pollution compared to current fossil fuel sources, according to researchers from the University of Delaware and Princeton University who have completed a first-of-its-kind simulation with the electric power industry.
The role of the tunnel
Freiburg researchers discover new molecular details about protein sorting in the cell.
The power of wind energy and how to use it
Wind offers an immense, never ending source of energy that can be successfully harnessed to power all of the things that currently draw energy from non-renewable resources.
The answer is blowing in the wind
Physics research provides new insights into the fluctuations of wind energy, with implications for engineering and policy.
Broken shoulder leads to carpal tunnel syndrome surgery study
After injuring his shoulder, a psychology professor collaborated with his orthopedic surgeon on a study to see how quickly patients regain their typing speed after carpal tunnel surgery.
AAOS Board approves treatment criteria for carpal tunnel syndrome and knee osteoarthritis
The American Academy of Orthopaedic Surgeons Board of Directors has approved new Appropriate Use Criteria (AUC) for the management of carpal tunnel syndrome and the surgical management of osteoarthritis of the knee.

Related Wind Tunnel Reading:

Low-Speed Wind Tunnel Testing
by Jewel B. Barlow (Author), William H. Rae (Author), Alan Pope (Author)

Transonic Wind Tunnel Testing (Dover Books on Engineering)
by Bernhard H. Goethert (Author)

When Neil Armstrong Built a Wind Tunnel (Leaders Doing Headstands)
by Mark Weakland (Author), Luciano Lozano (Illustrator)

Low Speed Wind Tunnel Testing
by Alan Pope (Author), John Joseph Harper (Author)

Wind Tunnels: Models, Aerodynamics and Applications
by Russell Mikel (Editor)

Wind Tunnel Testing of High-Rise Buildings (CTBUH Technical Guides)
by Peter Irwin (Author), Roy Denoon (Author), David Scott (Author)

Aerodynamic Analysis of the McLaren F1 Road Car using Wind Tunnel testing.

Wind Tunnel Testing for Buildings and Other Structures (Asce Standard)
by American Society of Civil Engineers (Author)

Wind-tunnel testing
by Alan Pope (Author)

Recommended Practice: Wind Tunnel Testing; Practitioners Volume
by AIAA (Author)

Best Science Podcasts 2018

We have hand picked the best science podcasts for 2018. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Circular
We're told if the economy is growing, and if we keep producing, that's a good thing. But at what cost? This hour, TED speakers explore circular systems that regenerate and re-use what we already have. Guests include economist Kate Raworth, environmental activist Tristram Stuart, landscape architect Kate Orff, entrepreneur David Katz, and graphic designer Jessi Arrington.
Now Playing: Science for the People

#504 The Art of Logic
How can mathematics help us have better arguments? This week we spend the hour with "The Art of Logic in an Illogical World" author, mathematician Eugenia Cheng, as she makes her case that the logic of mathematics can combine with emotional resonance to allow us to have better debates and arguments. Along the way we learn a lot about rigorous logic using arguments you're probably having every day, while also learning a lot about our own underlying beliefs and assumptions.