Method for detecting position of mobile body

A method for detecting a position of a mobile body on a plane with a position detecting sensor to detect the position of the mobile body in cooperation with a sensor in or on the mobile body moving on the plane, the method comprising the steps of:

• assuming X-Y coordinates, a plurality of X-axis direction reference lines parallel to an X-axis direction, and a plurality of Y-axis direction reference lines parallel to a Y-axis direction, on the plane;
• disposing one of the mobile body including the sensor at a predetermined position and a dummy mobile body including a sensor at a same position as the mobile body, on a plurality of intersection points of the X-axis direction reference lines and the Y-axis direction reference lines;
• acquiring calibration X-Y coordinate data by detecting the position of one of the mobile body and the dummy mobile body at each of the plurality of intersection points, with the position detecting sensor;
• determining position variation amounts in the X-axis direction and the Y-axis direction at the plurality of intersection points, as an X-axis direction error and a Y-axis direction error, based on a difference between the acquired calibration X-Y coordinate data, and true position data regarding the plurality of intersection points where one of the mobile body and the dummy mobile body is disposed;
• determining an X-axis direction error approximate formula and a Y-axis direction error approximate formula based on the X-axis direction error and the Y-axis direction error, the X-axis direction error approximate formula and the Y-axis direction error approximate formula each being a formula to calculate an error at each position on the plurality of X-axis direction reference lines and the plurality of Y-axis direction reference lines;
• and
• in a stage to actually detect the position of the mobile body moving on the plane, detecting a position of the mobile body moving on the plane with the position detecting sensor to acquire a detected X-Y coordinate data, and obtaining a position data close to a true position of the mobile body by correcting the detected X-Y coordinate data by a linear interpolation method using the X-axis direction error approximate formula and the Y-axis direction error approximate formula.