2006 Volume 72 Issue 12 Pages 1542-1546
Planar linear motor is a kind of 2D precision positioning stage, which is different from the usual XY stage and is composed of multiple linear motors arranged orthogonally in a same layer. It is a general way to employ a 3-axis laser interferometers and square-mirror as the positioning sensor of Sawyer planar linear motor for applications with nano meter order resolution. A geometrical calibration method is proposed according to the errors affecting the measurement of the laser interferometer, such as the profiles of the two plane mirrors and the flatness of platen. The method is easy to perform on the user side and useful to evaluate the single geometrical motion error without the standard square-gauge or the cross grid-scale. In this paper, the profiles of the x and y axis plane mirrors are measured by the tangent method and the straightness method respectively. For confirming the measurement results, the 2-point method with yawing compensation is applied to both of the mirrors.