Most complete exploration of fly landing maneuvers to advance future robots


By Erin Cassidy Hendrick

UNIVERSITY PARK, Pa. — To inspire advanced robotic technology, researchers in the Penn State Department of Mechanical Engineering have published the most complete description of how flying insects land upside-down.

The paper was published today (Oct. 23) in Science Advances.

“Through this work, we sought to understand how a fly executes the maneuvers of landing upside down in the blink of an eye,” said Bo Cheng, assistant professor of mechanical engineering and lead author of the paper.

It’s arguably the most difficult and least-understood aerobatic maneuver conducted by flying insects, according to Cheng.

“Ultimately, we want to replicate that in engineering, but we have to understand it first,” Cheng said.

Along with Penn State’s Jean-Michel Mongeau, assistant professor of mechanical engineering, and Pan Liu, doctoral student in mechanical engineering, Cheng aims to understand the biomechanical and sensory processes that flies use to land on different surfaces like ceilings and moving objects.

To gather their data, the team first examined the flies’ inverted landing behaviors in a flight chamber using high-speed videography. Their study found that the insects usually execute four perfectly timed maneuvers to land upside down: they increase their speed, complete a rapid body rotational maneuver (likened to a cartwheel), perform a sweeping leg extension and, finally, land through a leg-assisted body swing when their feet are firmly planted on the ceiling.

The researchers also believe these actions are set in motion by a series of complex visual and sensory cues the flies perceive as they approach their desired landing spot.

“Within the blink of an eye, these flies can totally invert their body and land, which is quite spectacular,” Mongeau said. “We see it all the time happening around us, but we’ve demonstrated the complexity of the maneuver. There is a lot of interest for robots to be able to do the same.”

However, current robotic technology sorely lacks the speed and efficiency needed to execute the same maneuvers.

“We look at nature for inspiration,” Mongeau said. “This helps drive the fundamental science of engineering, to understand how flies are able to solve these problems so we can apply them to future technologies.”

In addition to advancing robotics, the implications of this work can also be applied to the field of neuroscience.

“How is a fly’s nervous system able to do this so quickly?” Mongeau said. “This work reiterates how fast these maneuvers are executed within an extremely small nervous system. This data can lead to new hypotheses for understanding how brains function.”

Collaborators on the project include Sanjay P. Sane, associate professor at the National Centre for Biological Sciences in Bangalore, India, and Jianguo Zhao, assistant professor at Colorado State. The work was funded by a $500,000 grant from the National Science Foundation.


Share this story:

facebook linked in twitter email


Megan Lakatos

multiple images of a fly landing on a ceiling
A fly completing a series of complex maneuvers to land upside down on a ceiling. IMAGE: PENN STATE

“We look at nature for inspiration. This helps drive the fundamental science of engineering, to understand how flies are able to solve these problems so we can apply them to future technologies.”
—Jean-Michel Mongeau, assistant professor of mechanical engineering



With more than 60 faculty members, 330 graduate students, and 800 undergraduate students, the Penn State Department of Mechanical Engineering embraces a culture that welcomes individuals with a diversity of backgrounds and expertise. Our faculty and students are innovating today what will impact tomorrow’s solutions to meeting our energy needs, homeland security, biomedical devices, and transportation systems. We offer B.S. degrees in mechanical engineering as well as resident (M.S., Ph.D.) and online (M.S.) graduate degrees in mechanical engineering. See how we’re inspiring change and impacting tomorrow at

Department of Mechanical Engineering

137 Reber Building

The Pennsylvania State University

University Park, PA 16802-4400

Phone: 814-865-2519