Abstract
In order to realize straight motion at the highest level of accuracy, a system is introduced in which five degrees of freedom of a moving table; vertical and horizontal positions, and pitch, roll and yaw angles, are controlled precisely. The table is supported by active air bearings composed of PZT actuators and air pads. A PID-PD controller is designed achieving the table motion resolution of 0.02 μm and 0.02 arc sec. Errors of two degrees of freedom; horizontal position and yaw angle, were measured by a straight edge master, profile error of which was eliminated using the reversal method. Absolute accuracies of controlled straight motion were 0.14 μm in horizontal position and 0.14 arc sec in yaw angle over 600 mm travel.
