Patent ID: 6671650
Filing Date: 2003-12-30
Classification: G01B

Abstract:
A position measuring apparatus comprising:a target position detector for detecting a target position in a coordinate space with respect to a predetermined reference surface; a moving machine moving in accordance with a predetermined relation with respect to the reference surface so as to move said target position detector for the purpose of detecting the target position by said target position detector; a positional coordinate computer for computing a positional coordinate of the target position on the basis of a data such as a displacement of said moving machine; a position coordinate measuring mechanism constituted by said target position detector, said moving machine and said positional coordinate computer; a memory classifying geometrical errors on the basis of a positional coordinate measured by said position coordinate measuring mechanism and storing compensation parameters determined from the respective classified errors; an error compensator for reading out the compensation parameters so as to compensate the errors; and the target position within a specified coordinate space being measured on the basis of a coordinate system, wherein the position measuring apparatus comprises: a detector, comprising a reference side angle meter and a measurement side angle meter, for measuring whether or not a change is occurred in a relation with respect to said reference surface, in a movement executed by said moving machine; and an error corrector for correcting at least any one of the compensation parameter compensating the positional coordinates by said error compensator and the positional coordinate compensated by said error compensator in order to remove an influence given to the positional coordinate computed by the positional coordinate computer in correspondence to the relation between the movement executed by said moving machine and the reference surface, on the basis of an amount of change of the relation measured by said detector, in the case that the change is occurred.