Although they aren't as common as flying drones, we are seeing an increasing number of wall-climbing robots. What isn't so common, however, are devices like the VertiGo, which both drives on the ground and climbs up walls. Its climbing ability is particularly impressive, as it can even tackle walls with rough, uneven surfaces.
Created in a partnership between Disney Research Zurich and the ETH Zurich research institute, the VertiGo features a lightweight carbon fiber frame, two independently-tilting propellers, and four 3D-printed wheels (the front two of which are steerable).
In "ground mode" the rear prop is angled perpendicular to the ground, providing enough horizontal thrust to carry the machine across a variety of terrains. Upon reaching a wall, however, the front propeller kicks in and tilts upwards, pulling the front end of the robot up that wall. The rear prop continues to push the back end forward until it's also up against the wall.
From there, the VertiGo can roll vertically across the wall on its wheels, with a partial towards-the-wall tilt of the propellers pushing it in, so it doesn't simply fall off. Because it doesn't rely on suction like some other climbing robots, it doesn't require smooth, even wall surfaces with which to create a seal. This means it doesn't have a problem with walls made from brick and mortar, for example.
An onboard IMU (inertial measurement unit) and two infra-red distance sensors allow the robot to know whether it's oriented horizontally, vertically, or is about to transition between the two (i.e: when it's meeting up with the bottom of a wall), so its remotely-located human operator doesn't need to manually tilt the propellers.
The VertiGo can be seen in action, in the video below.