Patent ID: 8131385

Claim:
A positioning device comprising: moving means for relatively moving a positioning object; length measuring means for measuring a distance from a constant coordinate to the positioning object in a non-contact manner and for outputting a detection signal indicating a detection position of the positioning object in which the positioning object is detected only if the positioning object is positioned in a length measuring area within a predetermined range from any detection position; shaft control means for stopping the moving means by detecting the detection signal from the length measuring means and automatically correcting for an overshoot amount between a stop position of the positioning object via the moving means and said detection position of the positioning object, when the moving means relatively moves the positioning object and the length measuring means; and positioning control means for storing a coordinate value after the automatic correction by the shaft control means and performing the positioning of the positioning object based on the stored coordinate value, wherein the overshoot amount is a distance from the detection position of the positioning object after issuing an approach stop command by detecting the detection signal from the length measuring means to the stop position of the positioning object in which the movement means is stopped, and wherein overshoot amount correction for the positioning control means is made by performing a low speed movement from a first position to the detection position of the length measuring means and acquiring a second coordinate value of a second position where the movement stops by detecting that the positioning object is out of the length measuring area, and moving the positioning object in a reverse direction at a predetermined speed higher than the low speed to enter the length measuring area, and moving the positioning object to the second position at the low speed from the length measuring area if a stop position at the first position is out of the length measuring area.