Patent ID: 6847908

Claim:
A method for calibrating a machine having a base, a movable element, which is movable relative to the base in reference to an axis, and a control system for numerically controlling movement of the movable element in reference to the axis along a predetermined distance, the method comprising: identifying a plurality (N+1) of predetermined spaced-apart positions (i) along the predetermined distance, each of the positions (i) being associated with a desired position (DP r,i ), the desired position (DP r,i ) being representative of a desired location of the movable element in the predetermined distance; moving the movable element to each of the predetermined positions (i) in a first direction and calculating an error (E r,i ) between the desired position (DP r,i ) and an actual position (AP r,i ) of the movable element relative to the base and in reference to the axis at each of the predetermined positions (i); translating the structure to each of the predetermined positions (i) in a second direction opposite the first direction and calculating an error (E r+1,i ) between the desired position (DP r+1,i ) and an actual position (AP r+1,i ) of the movable element relative to the base and in reference to the axis at each of the predetermined positions (i); repeating the above two steps a predetermined number (R/2) of times; identifying at least two sources of assignable cause error; and quantifying the assignable cause error that is attributable to the at least two sources using at least one of the error (E r,i ) and the error (E r+1,i ).