Facebook filed a patent application for self-balancing robots

Facebook wants to patent a self-balancing robot that can switch between having two and three wheels, according to the patent's application document filed with the US Patent & Trademark office says.

Two-wheeled robots have the benefit of a small footprint but are limited in how much they can carry, so "there is a need for a robot that has both the height of a self-balancing, two-wheeled robot and the load carrying capacity of a three- or four-wheeled robot," the application says.

The robot transitions from three to two wheels by rotating its main "arm" (numbered 114 in the image) which then has the effect of raising the robot's "body "(numbered 102). This then lifts the third wheel (numbered 110, circled) away from the surface, and stands the body up onto the two "drive" wheels in preparation for self-balancing.

The application also says that the head unit (numbered 100) can include a screen, camera, microphone, and speaker, whereby "the display screen 132 and speaker 128 provide visual and audible output to a user interacting with robot 100," the document says. Whilst the application does not discuss potential uses for the robot, this head-unit description makes it sound similar to a telepresence robot - such as one found on robotshop.com, pictured - which is basically a remote-controlled, wheeled device that has wireless internet connectivity.

But unlike existing telepresence robots, Facebook's robot can store and carry things too, and this potentially explains the need for it to transition between a more stable three-wheeled mode and a self-balancing two-wheeled mode. It says: "In some embodiments, the body 102 can be configured with a storage region or a cargo support to carry items when the robot is in a three-wheeled mode."

The patent application also referenced an air flow cooling system whereby the robot can control its own temperature. You can read the full application document here.

It's worth noting that this is just a patent application, tech companies file thousands of patents every year that never make their way into finished products.