RoboCoaster Powered by Windows XP and Commercial RTOS on Single Computer

Those people have no idea how "exciting" this ride really is. The Kuka people who organized this stunt should be locked up for a while.

In these systems there will typically be a separate watchdog process monitoring the servo to see if it isn't lagging too far behind. If it is lagging too far, the system will brake and the kids would remain hanging upside down until someone can be bothered to reset the controller and bring them down. So let's assume that kind of fail-safety is there. Then still you cannot safeguard against plain mechanical failures. The head may brake, the chairs are likely not designed for shaking people upside down, it is a temporary exhibition setup so the base fixtures will not be tested properly and the whole thing may tumble. If the controling software flips a bit or has a bug, the watchdog process will not complain because the programmed path (into the concrete) is being followed just nicely.

While the robot brake system is likely to be fail-safe (it brakes when the power drops), the chairs did not seem to be designed that way at all. They are one-size-fits-nobody-but-your-200-pound-6-feet-bloke-type of chairs. The smaller children they apparently did let in didn't seem to have any kind of support and could even slip out.

"No worry, we use interrupts!" Yeah, right. Idiots.