Harvard Microrobotics Lab develops first insect-size robot capable of flying and swimming
In 1939, a Russian engineer proposed a "flying submarine" -- a vehicle that can seamlessly transition from air to water and back again. While it may sound like something out of a James Bond film, engineers have been trying to design functional aerial-aquatic vehicles for decades with little success. Now, engineers may be one step closer to the elusive flying submarine.
The biggest challenge is conflicting design requirements: aerial vehicles require large airfoils like wings or sails to generate lift while underwater vehicles need to minimize surface area to reduce drag.
To solve this engineers at the Harvard John A. Paulson School of Engineering and Applied Science (SEAS) took a clue from puffins. The birds with flamboyant beaks are one of nature's most adept hybrid vehicles, employing similar flapping motions to propel themselves through air as through water.
"Through various theoretical, computational and experimental studies, we found that the mechanics of flapping propulsion are actually very similar in air and in water," said Kevin Chen, a graduate student in the Harvard Microrobotics Lab at SEAS. "In both cases, the wing is moving back and forth. The only difference is the speed at which the wing flaps."
Coming from the Harvard Microrobotics Lab, this discovery can only mean one thing: swimming RoboBees.
For the first time, researchers at SEAS have demonstrated a flying, swimming, insect-like robot -- paving the way for future duel aerial aquatic robotic vehicles. The research was presented recently in a paper at the International Conference on Intelligent Robots and Systems in Germany, where first author Chen accepted the award for best student paper.
The paper was co-authored by graduate student Farrell Helbling, postdoctoral fellows Nick Gravish and Kevin Ma, and Robert J. Wood, the Charles River Professor of Engineering and Applied Sciences at SEAS and Core Faculty Member at the Wyss Institute for Biologically Inspired Engineering.
The Harvard RoboBee, designed in Wood's lab, is a microrobot, smaller than a paperclip, that flies and hovers like an insect, flapping its tiny, nearly invisible wings 120 times per second. In order to make the transition from air to water, the team first had to solve the problem of surface tension. The RoboBee is so small and lightweight that it cannot break the surface tension of the water. To overcome this hurdle, the RoboBee hovers over the water at an angle, momentarily switches off its wings, and crashes unceremoniously into the water in order to sink.
Next the team had to account for water's increased density.
"Water is almost 1,000 times denser than air and would snap the wing off the RoboBee if we didn't adjust its flapping speed," said Helbling, the paper's second author.
The team lowered the wing speed from 120 flaps per second to nine but kept the flapping mechanisms and hinge design the same. A swimming RoboBee changes its direction by adjusting the stroke angle of the wings, the same way it does in air. Like a flying version, it is still tethered to a power source. The team prevented the RoboBee from shorting by using deionized water and coating the electrical connections with glue.
While this RoboBee can move seamlessly from air to water, it cannot yet transition from water to air because it can't generate enough lift without snapping one of its wings. Solving that design challenge is the next phase of the research, according to Chen.
"What is really exciting about this research is that our analysis of flapping-wing locomotion is not limited to insect-scaled vehicles," said Chen. "From millimeter-scaled insects to meter-scaled fishes and birds, flapping locomotion spans a range of sizes. This strategy has the potential to be adapted to larger aerial-aquatic robotic designs."
"Bioinspired robots, such as the RoboBee, are invaluable tools for a host of interesting experiments -- in this case on the fluid mechanics of flapping foils in different fluids," said Wood. "This is all enabled by the ability to construct complex devices that faithfully recreate some of the features of organisms of interest."
This research was funded by the National Science Foundation and the Wyss Institute for Biologically Inspired Engineering.
Leah Burrows | EurekAlert!
Magnetic Quantum Objects in a "Nano Egg-Box"
25.07.2017 | Universität Wien
3-D scanning with water
24.07.2017 | Association for Computing Machinery
Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers
Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...
Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.
At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...
3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects
A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...
Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.
For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...
What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.
To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...
26.07.2017 | Event News
21.07.2017 | Event News
19.07.2017 | Event News
26.07.2017 | Physics and Astronomy
26.07.2017 | Life Sciences
26.07.2017 | Earth Sciences