Two-degree-of-freedom control design for ball screw driving table using full-closed loop

The high-speed positioning control of the mechatronics equipment is designed. In the mechatronics equipment of semiconductor-fabrication equipments and the machine tools, the high acceleration, the high speed, and high accuracy are demanded. The ball screw driving table with a motor and a ball screw is an extension of an existing technology, and the cost can be lowered. Because robustness to disturbance is high, the ball screw driving table is chiefly used in the feeding system for the mechatronics equipment. But the ball screw driving table has a lot of vibration modes that depend on low rigidities such as the ball screw and the bearings. In this paper, the full-closed control system for ball screw driving table is composed, and the feed-forward control of the model matching type is composed. The first vibration mode of the table is taken into consideration in the model. The control that considers the natural vibration mode is done according to the composition of a two-degree-of-freedom control that uses feedback and feed-forward. The two-degrees-of-freedom scheme has increased number of degrees of freedom of the design by using the reference and the error of the reference and controlled variable. The high speed and the high accurateness of the table driving are verified by the experiment.