Mitsubishi Corporation has developed a set of three interlocking gears that can move around in different movement patterns while spinning at full tilt — which in some cases can reach an astounding 6,000 rpm.
These three gears are running on an AC servo system. Each unit has three motors, and they're being controlled by a single multi-axis servo amp.
According to Mitsubishi, this level of timing requires micron level accuracy. That's about one millionth of a meter. Machines like this one, where the gears don't lose velocity or clash with each other, can be used for applications requiring insane amounts of precision, like mounting smartphone components or coating the glass panels in LCD TVs.
What's more, because one axis can be used as the energy source for another, it can be used for regenerative breaking (a good energy saving measure). This idea can be used in automotive, chip-making, printing, and food industries.