Position error evaluation method of moving device and method of improving movement accuracy based on evaluation results thereof

Abstract

Disclosed is a position error evaluating method of a moving device, which includes the following steps. Specifically, in a moving device which moves a movable body in two axial directions or in three axial directions orthogonal to each other, a straightness error curve indicating a state of change in a position error of the movable body along a uniaxial direction out of predetermined two axial directions is obtained by a sequential two-point method, the position error being related to a direction orthogonal to the predetermined two axial directions out of the biaxial or three axial directions. Then, the above step is repeated for the other uniaxial direction out of the two axial directions. Subsequently, straightness error curves indicating a state of change in a position error of the movable body along the other uniaxial direction is obtained based on coordinate positions of both ends of a group of already obtained straightness error curves, the position error being related to the direction orthogonal to the predetermined two axial directions. The straightness error curves at the coordinate positions of the both ends are set as a boundary straightness error curve. Thereafter, based on the boundary straightness error curves, alignment of the group of straightness error curves is corrected, thereby obtaining an error surface. Lastly, in accordance with the error surface, a two-dimensional position error of the movable body on a planar surface including the predetermined two axes is evaluated, the two-dimensional position error being related to a direction orthogonal to the planar surface. According to this method, in evaluating the position error of the moving device, compared to the conventional method, adjustment takes less time, and automatic evaluation can be easily performed. Thus, accuracy of a measuring device can be easily maintained.