Patent ID: 9002502
Filing Date: 2015-04-07
Classification: B23Q,G05B,Y10T

Abstract:
1. A method of calculating a correction value for a machine tool having two or more translational axes and one or more rotational axes to correct an error in one of a position and a position and posture of a tool with respect to an object to be machined, which results from a geometric error in the machine tool, comprising a step of: calculating a correction value for each of the translational axes using a command position of each of the rotational axes, a coordinate value of a correction reference point as one point designated in advance in a command position space of each of the translational axes, a command position of each of the translational axes to which the coordinate value of the correction reference point is assigned, and a geometric parameter representing the geometric error as a geometric relative error between the respective axes, wherein an error in a position of the tool in a work coordinate system of the object to be machined with the geometric parameter is calculated using: a position of the tool including the geometric parameter obtained by a homogeneous coordinate conversion from the tool coordinate system to the work coordinate system of the object to be machined, and an optimal position of the tool where the geometric parameter is not included obtained by a homogenous coordinate conversion from the tool coordinate system to the work coordinate system of the object to be machined, and wherein the calculated error in the position of the tool is converted to a command value coordinate system for the respective axes by a homogeneous coordinate conversion from the work coordinate system to the command value coordinate system to provide the calculated correction value for each of the translational axes.