WORKPIECE PLACEMENT ERROR MEASURING DEVICE

Title:

WORKPIECE PLACEMENT ERROR MEASURING DEVICE

Document Type and Number:

Japanese Patent JP2006289524

Kind Code:

A

Abstract:

To measure an error in placement of a three dimensional workpiece.

The workpiece 1' is placed on a table of a machine tool, and a coordinate system (X', Y', Z') is established on the workpiece. Positions A, B, C, D, E, F, G, H, and I, i.e., three points on the three surfaces of the workpiece 1' orthogonally crossing one another, are detected by a touch probe 2. Three formulae of the three planes each passing through the three points on the same surface are derived. The position O' (Xo, Yo, Zo) of the point where the three formulae of the three planes intersect one another is obtained. This position indicates a parallel translation error. Points on the X', Y' and Z' axes having a distance of L from the point O' are determined. A rotation matrix is obtained by these three points, the position O' (Xo, Yo, Zo) and the distance L. A rotational error is obtained by using the rotation matrix. The error in placement of the three dimensional workpiece comprising the three dimensional parallel translation errors and the rotational direction error is obtained.

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