[Groundbot, Image Soure: PopSci]
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The Rotundus is driven by a pendulum inside the spherical casing. This pendulum controlled by a motor gives the robot direction. Getting the pendulum to move forward makes the robot to roll forward and moving it left or right gives it the ability to steer. The makers of this robot hope to make it autonomous with improvements. They hope to integrate in it a GPS so that it can follow specified routes to patrol and to incorporate radar sensors to help move about obstacles. They also plan to give it sufficient power to move up on slopes.
[Rotundus: Image Source]
From Popular Science:
The GroundBot is a spherical sentry designed to roll up to 6 mph through just about anything—mud, sand, snow and even water. Two gyroscopically steadied wide-angle cameras and a suite of sensors give remote operators a real-time, 360-degree view of the landscape, letting them zoom in on prowlers or detect gas leaks, radioactivity and biohazards. Originally invented by Swedish physicists to explore other planets, the GroundBot features a tough design that requires almost no maintenance and can also be programmed to run autonomously. Its sealed shell protects its interior against grit and allows it to survive steep drops, while a rubber skin dampens vibration and provides traction. To get rolling, the robot simply shifts its weight. Its center of mass is suspended from a pendulum inside the sphere, so motors just push the pendulum to the front, to the back, or to the side. Lithium-ion batteries provide up to 16 hours of spy time.
The advantages of a spherical robot are manifold, its design is extremely non-complicated. It offers good protection to the sensors and equipment sealed inside the sphere. Rotundus is very light, just about 25 Kilos, but the low weight advantage is multiplied as the rotundus is sealed. That means that it has a low density and can thus float. Thus it may be used to operate on-road, off-road and over water! Sealing the bot has other advantages than simply allowing the robot to have low density so that it can float, it also ensures that no sand can get inside to interfere with the motors and etc. The sealing also makes the robot of good use in gas leak scenarios as electrical sparks (if any) in the inside are sealed off. The design also makes the robot a very silent operator.
Check the following video showing the Rotundus roll along in snow:
The Rotundus has some obvious limitations. Like it can’t operate properly inside buildings as it can’t move up stairs. For such purposes biologically inspired bots remain the best bet IMO. See some of them here, really cool research: