Getting drones to perch via electroadhesion

Drone advocates predict that the unmanned aerial vehicles will become indispensable in many settings, such as disaster situations, by taking video to assess environmental conditions or chemical hazards to help emergency responders navigate safely. The challenge, particularly for insect-sized drones, is battery power, which gets used up quickly when the devices are hovering. If the aerial vehicles could be made to perch on something, however, batteries could be conserved to increase mission lifetime. A team led by Moritz A. Graule of MIT and Robert J. Wood of Harvard University has developed drones that do just that, using electroadhesion to perch and improving power consumption by a factor of 1,000 (Science 2016, DOI: 10.1126/science.aaf1092). Although researchers have previously devised various perching tactics, the electroadhesion strategy is particularly valuable because it works on a variety of materials—leaves, wood, and steel—and on a variety of surfaces—from rough to smooth. The electroadhesion involves embedding a maze-like circuit into a nonconducting polymer—in this case, a polyimide film. When a voltage is established across the surface of this device, it becomes charged and an opposite charge is induced along the surface of any material it comes in contact with. Adhesion is achieved by electrostatic attraction between the two surfaces.