If you've got the right sensors, any unexpected resistance could be used as a trigger to stop motion faster than any human could do it.
The SawStop system does it with electrical conductivity, but feedback from servos will do as well.
The SawStop system does it with electrical conductivity, but feedback from servos will do as well.
But they don't have proximity sensors - like the saw capacitance sensor. It just doesn't work in the real world with large objects and longer distances.
You have to rely on the actors staying on their marks if you want to do a very close approach.