Over the last few years, inertial sensing systems have made significant progress as sensors and actuators have become more powerful and cheaper. For instance, although it did not change the world in the way that it was intended, the Segway has become ubiquitous enough that everyone knows what it is, and inertial sensing platforms are regularly included in consumer products from smart phones to golf clubs. However, this ball balancing robot from the Robot Development Engineering Laboratory at Tohoku Gakuin University in Japan is one of the coolest implementations of this type of system that I have seen.
Although ball balancing robots are not new (from a controls perspective, it is a great example of the classic inverted pendulum problem), there are several noteworthy features about this robot. First, the robot is omnidirectional and can rotate around its vertical axis (zero turning radius). Second, it has a passive control mode so you can push it around without exerting much force – the video shows some good examples of this. These two wrinkles considerably increase the versatility of the robot.
The other thing that is cool about this project is the accessibility of the hardware. It uses a 16-bit MCU with a few sets of accelerometers and gyros, all of which are readily available for on the order of a few dollars, even at prototype volumes. And, since the project was publicized in 2010, companies like Invensense, ST, and Kionix have released integrated 6-axis chips (a 3-axis accelerometer and 3-axis gyro on the same die with integrated signal processing) and announced the imminent release of 9-axis chips (add a 3-axis magnetometer for orientation using the earth’s magnetic field). Advances like these are just more evidence of how feasible it is becoming to implement remarkably cool functionality into consumer products. Personally, I can’t watch the video without imagining this robot as a mobile drink tray – hopefully something like it will be bringing me a beer before I know it.