Abstract
This paper describes a new levitation control method of linear magnetic bearings for a linear arm in clean robot without any mechanical contact. The linear arm consists of a slender beam like a ladder and carries a silicon wafer on a tip. It is levitated by linear magnetic bearings and is driven by a linear stepping motor without any mechanical contact. A new control method for the linear active magnetic bearing is applied for its levitation, in which the bias current of each magnet is changed according to the distance between the center of the bearing and the center of gravity of the arm. The experiments have been carried out on the levitation control while the arm is moved by the linear stepping motor. The experiment shows that the arm is levitated and moves smoothly without any mechanical contact.
