Design World

  • Home
  • Technologies
    • 3D CAD
    • Electronics • electrical
    • Fastening & Joining
    • Factory automation
    • Linear Motion
    • Motion Control
    • Test & Measurement
    • Sensors
    • Fluid power
  • Learn
    • Ebooks / Tech Tips
    • Engineering Week
    • Future of Design Engineering
    • MC² Motion Control Classrooms
    • Podcasts
    • Videos
    • Webinars
  • LEAP AWARDS
  • Leadership
    • 2022 Voting
    • 2021 Winners
  • Design Guide Library
  • Resources
    • Subscribe!
    • 3D Cad Models
      • PARTsolutions
      • TraceParts
    • Digital Issues
      • Design World
      • EE World
    • Women in Engineering
  • Supplier Listings

Stanford Engineers Build Win Tunnel for Birds, Paves Way for Better Drones

By Stanford University | April 22, 2016

Share

 

Most people look at a pigeon and see a chubby, common, boring bird. A “rat with wings,” in common New Yorker parlance. When David Lentink watches a pigeon dart around a building and land perfectly in its roost, however, he sees the future of robotic flight.

Lentink, an assistant professor of mechanical engineering at Stanford, has been studying birds in flight for years, with an eye toward applying the tricks birds use to navigate changing conditions in the real world to design better aerial robots. Most of the insights he and his colleagues have gained so far have resulted from painstaking study, involving calculations of wing force dynamics inspired by footage captured in the wild.

Now, with the construction of one of the most advanced bird wind tunnels in the world, Lentink hopes to reveal even more of the magic of bird flight. 

With the recent boom in drone use, it’s easy to forget that the robots frequently fail in windy conditions. Consider flying a drone down an “urban canyon” like Fifth Avenue in New York City. Turbulence varies wildly from the middle of the “canyon” to alongside the skyscrapers, and obstacles like traffic lights pop up frequently. Now, throw in a few dozen drones fighting for position like the taxis below. It’s a nightmare for drone operators.

“But you look up, and you’ll see a pigeon swoop by casually. It has no problem stabilizing itself, flying around corners, dodging cables and landing on a perch,” Lentink said. “It’s just something we haven’t accomplished in robotics yet. We need to study birds up close so we can figure out what their secret is to flying so stably under such difficult conditions, and apply that to aerial robotic design.”

The new wind tunnel works like a super tricked-out treadmill for birds. The windflow, generated by a fan roughly the size of a Volkswagen Beetle, is super smooth: Turbulence checks in around .015 percent, less than half of any other bird wind tunnel in the world. This allows the researchers to study how birds fly in smooth-flowing air such as that found at higher altitudes.

Such conditions aren’t typical closer to the ground, particularly around trees and buildings, though, so the tunnel is fitted with a “turbulence generating system,” a series of computer-controlled wind vanes that can precisely simulate different turbulence patterns, creating up to 50 percent turbulence. In this state, the flow moves almost equally randomly in all directions, making it very unpredictable for the bird.

Cruising speed for birds

Wind speed is also highly tunable. The lovebirds, parrotlets, and hummingbirds that Lentink’s lab studies typically cruise around 7 meters/second, which the engineers can match perfectly to study sustained flight. They will occasionally crank the flow up to 15 m/s, which simulates a strong wind, maxing out at 20 m/s for large birds.

Lentink is fiercely protective of his birds, and said this would be the maximum speed he would consider letting larger birds fly to keep them comfortable. The tunnel can blow much faster, however, with speeds up to 50 m/s for the prototype drones he plans to test in the tunnel.

Nearly two meters long, the six-sided windowed observation section of the tunnel provides Lentink and his students a variety of ways to study bird flight. They currently zero in on specific aspects of birds’ wing beats, using high speed cameras as well as motion capture techniques more commonly utilized in Hollywood films, recording wing motion millisecond by millisecond. They then translate these measurements to precise calculations of the force dynamics experienced along the birds’ wings and in the surrounding air. Later this summer, Lentink expects to introduce two fluoroscopes to the mix, which will allow researchers to “see inside” the bird and visualize the exact muscular-skeletal movements it makes in different flight maneuvers.

Once his team has trained enough birds, Lentink plans to fly entire flocks in the tunnel to determine how turbulence created by one bird’s wing beats affects a nearby bird, and how they maneuver for position. Both of these measurements will provide critical foundational information for a future sky packed with drones.

Using the information gleaned from bird flights, Lentink envisions using the tunnel as a test-bed for new aerial robot designs. In addition to establishing better maneuverability controls for common quadcopter designs, he’s particularly interested in building bird-like, winged robots that quickly morph their wing shape in order to maintain stability in turbulent air flows.

Tricks birds teach us

“Ever since Otto Lilienthal and the Wright Brothers studied birds to invent their airplanes, engineers have relied on talking with biologists to learn the tricks birds us,” said Lentink, who is a member of Stanford Bio-X. Although the wind tunnel will enable engineers to develop safer and more reliable drones that fly in urban environments as well as birds do, Lentink stressed that it is not only an engineering facility. It is a top-notch biology lab that meets and exceeds all animal research standards enabled by the very best technology Stanford offers.

Lentink, who is both a biologist and an engineer, teaches engineering students and biology postdocs how to collaborate.

“Our bird tunnel is really unique, and I’m incredibly thankful to my colleagues and the School of Engineering who thought it was an awesome idea to enable engineering students to study how birds fly to develop better flying robots and made this possible,” Lentink said. “The facility has been built with great care by people within the School of Engineering, and I’m really excited about the opportunity to study bird flight up close with engineering students who bring different interests ranging from biomechanics to fluid mechanics to aeronautics in our team of engineers and biologists.”

The wind tunnel was paid for by Stanford. The various measurement systems were acquired with support from the Air Force, Navy, Army, Human Frontiers Science Program, and Stanford Bio-X program.


Filed Under: M2M (machine to machine)

 

Related Articles Read More >

Part 6: IDE and other software for connectivity and IoT design work
Part 4: Edge computing and gateways proliferate for industrial machinery
Part 3: Trends in Ethernet, PoE, IO-Link, HIPERFACE, and single-cable solutions
Machine Learning for Sensors

DESIGN GUIDE LIBRARY

“motion

Enews Sign Up

Motion Control Classroom

Design World Digital Edition

cover

Browse the most current issue of Design World and back issues in an easy to use high quality format. Clip, share and download with the leading design engineering magazine today.

EDABoard the Forum for Electronics

Top global problem solving EE forum covering Microcontrollers, DSP, Networking, Analog and Digital Design, RF, Power Electronics, PCB Routing and much more

EDABoard: Forum for electronics

Sponsored Content

  • Industrial disc pack couplings
  • Pushing performance: Adding functionality to terminal blocks
  • Get to Know Würth Industrial Division
  • Renishaw next-generation FORTiS™ enclosed linear encoders offer enhanced metrology and reliability for machine tools
  • WAGO’s smartDESIGNER Online Provides Seamless Progression for Projects
  • Epoxy Certified for UL 1203 Standard

Design World Podcasts

July 26, 2022
Tech Tuesdays: Sorbothane marks 40 years of shock and vibration innovation
See More >
Engineering Exchange

The Engineering Exchange is a global educational networking community for engineers.

Connect, share, and learn today »

Design World
  • Advertising
  • About us
  • Contact
  • Manage your Design World Subscription
  • Subscribe
  • Design World Digital Network
  • Engineering White Papers
  • LEAP AWARDS

Copyright © 2022 WTWH Media LLC. All Rights Reserved. The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of WTWH Media
Privacy Policy | Advertising | About Us

Search Design World

  • Home
  • Technologies
    • 3D CAD
    • Electronics • electrical
    • Fastening & Joining
    • Factory automation
    • Linear Motion
    • Motion Control
    • Test & Measurement
    • Sensors
    • Fluid power
  • Learn
    • Ebooks / Tech Tips
    • Engineering Week
    • Future of Design Engineering
    • MC² Motion Control Classrooms
    • Podcasts
    • Videos
    • Webinars
  • LEAP AWARDS
  • Leadership
    • 2022 Voting
    • 2021 Winners
  • Design Guide Library
  • Resources
    • Subscribe!
    • 3D Cad Models
      • PARTsolutions
      • TraceParts
    • Digital Issues
      • Design World
      • EE World
    • Women in Engineering
  • Supplier Listings