Abstract
In order to realize perfect cleanness in semiconductor manufacturing process, we are developing a clean robot, in which the magnetic bearing is used for a joint of the robot. This paper mainly reports a new control method of magnetic levitation of the linear actuator in the clean robot that conveys a silicon wafer in a high vacuum clean room. As the linear arm of the actuator is flexible, the H infinity control method has been adopted for the levitation control and its performance is compared with that of PID. The gain-scheduling technique that changes a controller gain according the position of the arm has been introduced because of large change of distance between the center of gravity of the arm and the center of actuator in operation. The stable levitation and transference of the arm has been confirmed by experiments.
