[dsr_]

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.

[tintin]

I don't think the feedback of the servos will detect a human body part. These servos are very very strong. Maybe when it hit the concrete it will skip a step noticeable in the feedback but that's about it.

[Qworg]

This still imparts quite a bit of force to someone, potentially killing them.

[wojtczyk]

This is a 1 ton robotic arm. It won't notice a bit when it hits somebody

[excuse-me]

They have envelope protection, in software, so if you tell the controls the size and shape of the camera and the surrounding objects they wont drive the camera through the floor whatever path you program in.

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.