[Replaced] Balancing a ball on a spool (Raspberry Pi with the Monarco HAT)

This video is outdated and was replaced: https://youtu.be/lKhs4z0jOz8
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How about balancing a ball on a metal spool?
The Monarco HAT allows reading a distance using an ultrasonic sensor. It can also read quadrature encoder signals and control a motor. And if we combine all this together, it seems like magic.

The Raspberry Pi processes the measured signals and controls the rotation of the spool. The spool rotates clockwise or anticlockwise, faster or slower, depending on the position of the ball. The necessary action is computed 200 times per second, over and over again with the measured values changing all the time. This principle is called feedback control.

The ball can be either stationary or revolving. In both cases it stays on top of the spool until the control algorithm is switched off...

Setup:
Monarco HAT
Raspberry Pi 2
Servoamplifier Maxon DES 50/5
Ultrasonic distance sensor Banner S18UUA
REX Control System runtime

Видео [Replaced] Balancing a ball on a spool (Raspberry Pi with the Monarco HAT) канала REX Controls