MACHINING STATE CHECKING METHOD AND MACHINING STATE CHECKING APPARATUS

• US 20100063617A1
• Filed: 09/03/2009
• Published: 03/11/2010
• Est. Priority Date: 09/05/2008
• Status: Active Grant

• Current Assignee: MORI Seiki Company Limited (Dmg Mori Co., Ltd.)
• Original Assignee: MORI Seiki Company Limited (Dmg Mori Co., Ltd.)
• Inventors: Mori, Masahiko, Fujishima, Makoto, Tian, Xiaodong, Zhao, Bingyan, Jin, Zhe
• Granted Patent: US 8,180,476 B2
• Time in Patent Office: Days
• US Class Current: 700/175
• CPC Class Codes: B23Q 17/20 for indicating or measuring workpiece characteristics, e.g. contour, dimension, hardness
• CPC Class Codes: B23Q 17/24 using optics or electromagnetic waves
• CPC Class Codes: G05B 19/402 characterised by control arrangements for positioning, e.g. centring a tool relative to a hole in the workpiece, additional detection means to correct position G05B19/19 takes precedence
• CPC Class Codes: G05B 2219/37555 Camera detects orientation, position workpiece, points of workpiece
• CPC Class Codes: G05B 2219/37563 Ccd, tv camera
• CPC Class Codes: G05B 2219/37572 Camera, tv, vision
• CPC Class Codes: G05B 2219/50064 Camera inspects workpiece for errors, correction of workpiece at desired position

Abstract

The present invention provides a machining state checking apparatus and method for checking whether a workpiece mounted on a machine tool and a workpiece fixture are shifted. A machining state checking apparatus has an actual CCD camera for imaging a workpiece fixed on a machine tool and a workpiece fixture and generating actual two-dimensional image data thereof, a virtual image generating section for generating virtual two-dimensional image data of the workpiece and workpiece fixture based on data on three-dimensional models of the workpiece and workpiece fixture, a comparing section for comparing the actual two-dimensional image data and virtual two-dimensional image data generated by the actual CCD camera and the virtual image generating section, respectively, and determining whether they match each other by comparing the portions corresponding to the workpiece and workpiece fixture in the actual two-dimensional image and the virtual two-dimensional images of the workpiece and workpiece fixture.

Claims

1. A machining state checking method for checking, in a machine tool machining a portion to be machined of a workpiece fixed by a workpiece fixture to form a predetermined machining shape on the workpiece, whether the workpiece or the workpiece fixture is shifted, or whether the predetermined machining shape is formed by machining, the machining state checking method comprising:

an actual image generating step of imaging a pre-machined workpiece, workpiece having the predetermined machining shape formed thereon, or the workpiece fixture, which are fixed on the machine tool, by means of actual imaging means from a predetermined view point, and generating actual two-dimensional image data thereof;

a virtual image generating step of generating virtual two-dimensional image data of the workpiece, workpiece fixture, or machining shape of the workpiece, based on data on a three-dimensional model of the workpiece or workpiece fixture, the virtual image generating step in which;

a three-dimensional space is virtually set;

three-dimensional model of the workpiece including the machining shape, three-dimensional model of the workpiece excluding the machining shape, three-dimensional model of the workpiece fixture, or three-dimensional model of the machining shape of the workpiece is arranged in the virtual three-dimensional space, and simultaneously imaging means having the same condition as that of the actual imaging means is virtually set and arranged; and

then virtual two-dimensional image data which is assumed to be obtained when the workpiece, workpiece fixture, or machining shape is imaged by the virtual imaging means from the same view point as that of the actual imaging means, is generated; and

a comparing step of comparing the actual two-dimensional image data and virtual two-dimensional image data generated in the actual image generating step and the virtual image generating step, respectively, the comparing step of comparing the portion corresponding to the workpiece, workpiece fixture, or machining shape in the actual two-dimensional image and the virtual two-dimensional image of the workpiece, workpiece fixture, or machining shape of the workpiece, and determining whether they match each other.

2. A machining state checking apparatus for checking, in a machine tool machining a portion to be machined of a workpiece fixed by a workpiece fixture to form a predetermined machining shape on the workpiece, whether the workpiece or the workpiece fixture is shifted, or whether the predetermined machining shape is formed by machining, the machining state checking apparatus comprising:

actual imaging means for imaging a pre-machined workpiece, workpiece having the predetermined machining shape formed thereon, or the workpiece fixture, which are fixed on the machine tool, from a predetermined view point, and generating actual two-dimensional image data thereof;

model data storage means for storing data on a three-dimensional model of the workpiece or workpiece fixture;

virtual image generating means for generating virtual two-dimensional image data of the workpiece, workpiece fixture, or machining shape of the workpiece, based on the model data stored in the model data storage means, the virtual image generating means in which;

a three-dimensional space is virtually set;

a three-dimensional model of the workpiece including the machining shape, three-dimensional model of the workpiece excluding the machining shape, three-dimensional model of the workpiece fixture, or three-dimensional model of the machining shape of the workpiece is arranged in the virtual three-dimensional space, and simultaneously imaging means having the same condition as that of the actual imaging means is virtually set and arranged; and

then virtual two-dimensional image data which is assumed to be obtained when the workpiece, workpiece fixture, or machining shape of the workpiece is imaged by the virtual imaging means from the same view point as that of the actual imaging means, is generated; and

comparing means for comparing the actual two-dimensional image data and virtual two-dimensional image data generated by the actual imaging means and the virtual image generating means, respectively, the comparing means for comparing the portion corresponding to the workpiece, workpiece fixture, or machining shape of the workpiece in the actual two-dimensional image and the virtual two-dimensional image of the workpiece, workpiece fixture, or machining shape of the workpiece, and determining whether they match each other.

3. The machining state checking apparatus according to claim 2, wherein

the comparing means comprising:

an edge extracting section for, based on the virtual two-dimensional image data generated by the virtual image generating means, extracting an edge corresponding to at least the contour line of the workpiece, workpiece fixture, or machining shape of the workpiece from the edges in the virtual two-dimensional image;

an edge detecting section for, based on the actual two-dimensional image data generated by the actual imaging means, detecting an edge corresponding to at least the contour line of the workpiece, workpiece fixture, or machining shape of the workpiece from the actual two-dimensional image; and

an edge comparing section for comparing the edge extracted by the edge extracting section and the edges detected by the edge detecting section, and determining whether they match each other.

4. The machining state checking apparatus according to claim 3, wherein

the comparing means includes a detection area setting section for, based on the edge extracted by the edge extracting section, setting a detection area including the extracted edge and having a given width along the extracted edge, and

the edge detecting section is configured to detect an edge existing in the detection area on the actual two-dimensional image as the edge corresponding to the contour line, based on the detection area set by the detection area setting section and the actual two-dimensional image data generated by the actual imaging means.

5. The machining state checking apparatus according to claim 3, wherein

the edge comparing section is configured to determine that the edge detected by the edge detecting section and the edge extracted by the edge extracting section match each other when the relationship between the sum of the length of the edge detected by the edge detecting section and the sum of the length of the edge extracted by the edge extracting section satisfies a predetermined standard.

6. The machining state checking apparatus according to claim 4, wherein

the edge comparing section is configured to determine that the edge detected by the edge detecting section and the edge extracted by the edge extracting section match each other when the relationship between the sum of the length of the edge detected by the edge detecting section and the sum of the length of the edge extracted by the edge extracting section satisfies a predetermined standard.