October 04, 2016      

There are many different ways to classify robots, but perhaps one interesting method would be to group them into robots that don’t tip over if they are turned off and those that do.

Most seem to fall into the first category, but here are several robots that actively balance themselves with dynamic guidance systems. This roundup doesn’t include legged systems, which we covered here.

Bike-riding Robot

Humans, supposedly, never forget how to ride a bike, but that’s a much tougher skill for a robot to master. The robot seen below, however, makes it seem easy. The robot, a commercially-available bipedal model, is programmed to push the pedals with its feet, stopping the bike by putting its feet down.

The robot then waves to the crowd when stopped. The robot’s creator, who is interested in artificial intelligence, views the robot’s skill of riding a bike as having an equal value to what we would normally classify as “intelligence.”

The direction of this robot is controlled by a remote, and the lower-level balancing functions are controlled by a gyroscope embedded in its custom backpack. It interprets data from the gyroscope via a PID algorithm, taking into account proportional, integral, and derivative components of the robot’s motion. This method is a common control scheme that is likely used in most, if not all, robots in this roundup.

Robot Balances On A Ball

Balancing a bicycle is hard enough, but perhaps one could point out that it’s only unstable in one direction. Here’s a robot that can balance in both the “X” and “Y” direction on whatever ball happens to be available. It uses wheels with rollers embedded in them, allowing it to adjust its position in any direction with careful rolling coordination. You might recognize this as a version of the “inverted pendulum” control design problem, though with several complicating factors thrown in.

Another great feature is that one of these robots can be used to assist a human if he or she needs to balance an entire load on it. It can even assist if only part of the load needs to be supported, sort of like an extremely complicated wheelbarrow. If all of that wasn’t enough, several of these robots can be used together, each supporting part of a load. A cart might be simpler, but what fun would that be?

If you’re interested in what the roller wheels this robot uses, here’s a look at a more stable model.

Satellite Tech Comes to Earth in the Cubli

Whenever you start or stop a rotating mass, whatever it is attached to has to react in an opposing manner. This is used to control satellites in space where there is nothing restricting movement. But with a powerful motor and rotating mass, this same method can be used on the earth. If three masses are used, this change in motion can be induced in three different rotational directions.

The Cubli, a 15 cm cube, does just this. With three internal masses (“reaction wheels”) and advanced control software, it can balance on its corners and edges. It can even stay in place while the surface underneath it is angled or if someone pushes it intentionally. Besides balancing, it uses its momentum to roll across a surface, jumping up on an edge and falling down on the next face.