We’ve all seen how birds can perch on a branch, insects stick to walls, and bats cling upside down. It saves an enormous amount of energy, but it does require the necessary skill to perch in the first place. How do you do that with a tiny robot? Using static electricity.
It’s possible for an object to cling to a surface using a static charge. However, the adhesion is quite weak so the weight has to be kept as low as possible. The research team did that by making their 36mm RoboBee flying robots weigh just 84 milligrams. For comparison, a typical adult bee weights 120mg.
On top of each RoboBee is an electrode patch that generates the static charge which creates the adhesion. Remove the charge and the adhesion is broken, but while attached no flying is required and the RoboBee’s battery isn’t being drained beyond generating the static charge and any other tasks being carried out e.g. monitoring the area using an embedded sensor.
The adhesion works with glass, wood, and even vegetation such as the underside of a leaf. With further development it is hoped vertical surfaces can also be supported allowing the robots to perch sideways rather than just upside down. The team also needs to get rid of that tether so the robots become autonomous.
Another feature I bet they could add is perching to recharge the battery at a base station. This would keep the delicate robots off the ground while allowing the recharge plate to be kept out of reach of anyone or anything other than the robots.