Robots have been able to fly for a while, which is great, but roboticists are still trying to figure out the next big step: A robot that is able to perch on a variety of surfaces and take off again. This tiny insect-inspired robot by researchers from MIT and Harvard has demonstrated the ability to do just that.
The tiny robot measures just 20 millimetres in height (less than the size of a quarter), with a wingspan of 36 millimetres and a weight of just 84 milligrams. This poses some interesting challenges when it comes to perching. There's limited space for grippers or feet, and the robot's payload is likewise small, so significantly adding to its weight will possibly inhibit flight.
Led by Moritz Alexander Graule of MIT and Robert Wood of Harvard, the team developed an adhesion pad that uses an electrostatic charge. This works like sticking a balloon to a wall after rubbing it on your hair, but using supplied power rather than triboelectricity. This has allowed the robot to stick to a variety of surfaces, including glass, plywood and leaves, and take off again without issue.
As described in the paper, published and available for free in the journal Science, the electrostatic adhesion pad is made of foam so that the robot can attach to a target without bouncing off again. When the robot approaches a surface, the adhesion pad is turned on to perch; to take off again, the pad is turned off, allowing the robot to detach from the surface.
At the moment the robot is too small to fly untethered, since a battery that could power it for a worthwhile amount of time would be heavier than the robot could manage. However, a perching system could reduce the need for a larger battery. The robot's flight power is 19 milliwatts, and its perching power is 6.9 microwatts for glass (less for other surfaces).
A robot deployed in the field, therefore, could perch to conserve energy rather than hovering non-stop, meaning it could spend a lot longer on a mission, finding a good vantage point from which to conduct surveillance and staying there until required to move again.