Question: If you were to move a robots arm, would it focus on the degrees of the motors turning, or the actual angle of the arm

Alan Winfield answered on 24 Mar 2011:

Gosh – that’s quite a technical question! In fact both. Some robot arms work out how much to move each joint by turning the motors by a certain angle – the motors are fitted with what are called optical shaft encoders, or they might be stepper motors that only turn a given number of steps (very small angles). Other robots have sensors that tell the controller the angle of the joints – so the controller moves the motors until the angle sensor tells it that the joint is at the required angle – it’s something called closed-loop control.