Developed in the labs of Mark Cutkosky, the Fletcher Jones Chair in the School of Engineering at Stanford University, and Dario Floreano at the École Polytechnique Fédérale de Lausanne in Switzerland, FlyCroTugs are micro air vehicles that the researchers have modified so the vehicles can anchor themselves to various surfaces using adhesives inspired by the feet of geckos and insects, previously developed in Cutkosky’s lab.

With these attachment mechanisms, FlyCroTugs can pull objects up to 40 times their weight, like door handles in one scenario, or cameras and water bottles in a rescue situation. Similar vehicles can only lift objects about twice their own weight using aerodynamic forces.

“When you’re a small robot, the world is full of large obstacles,” said Matthew Estrada, a graduate student at Stanford and lead author of a paper on FlyCroTugs, published Oct. 25 in Science Robotics. “Combining the aerodynamic forces of our aerial vehicle along with interaction forces that we generate with the attachment mechanisms resulted in something that was very mobile, very forceful and micro as well.”

The researchers say the FlyCroTugs’ small size means they can navigate through snug spaces and fairly close to people, making them useful for search and rescue. Holding tightly to surfaces as they tug, the tiny robots could potentially move pieces of debris or position a camera to evaluate a treacherous area.

Fans of James P. Hogan recall the hardworking repair drones from his 1979 book The Two Faces of Tomorrow:

A sudden rushing sound, like that of high-velocity ducted air, mixed with a fainter electric whine, came from halfway up the wall to their right... It was an array of open compartments that looked like pigeon holes for mail, except that each was a foot or more square...

The noise was coming from one of these objects. The object that it was coming from was a dull-gray cylinder about six inches across, lying on its side on top of a flat tubular framework that contained a mass of tightly packed gadgetry and wiring. The near end of the cylinder was distinctly insectlike, with a profusion of miniature probes and jointed arms, and a circle of recessed windows that could have been lens apertures.

It extended three of its tiny arms sideways to lock onto the registration pins located at intervals across the face and then, holding itself quite steady in the air, traversed slowly sideways until its axis was aligned with the array element from which Chris had taken the cartridge.
(Read more about the repair drones)