Me and a fellow student are having a couple of issues regarding Reachy’s head movement:
We do not know how to avoid that the head’s position reaches its limit (we assume that’s the blue LED on the head is trying to indicate - once it flashes, the head does no longer move properly afterwards).)
We also do not know how to recover in case such a case arises, so far, we went with the very reliable “turning it off and on again”.
The blue LED blinking actually indicates an orbita safety shutdown due to the motors overheat. This usually happens when the motors are forcing. Indeed, when this happens you need to turn it off and on again. But make sure you wait for the motor to cool down before turning it on again.
The limits for each disk are in fact dependent of each other. So, unfortunately there is no simple way to know if you reached the limit. The best option is to check whether the motor reached the target position you set or not.