WORKPIECE MEASURING DEVICE, COLLISION PREVENTING DEVICE, AND MACHINE TOOL

• US 20120089247A1
• Filed: 11/10/2009
• Published: 04/12/2012
• Est. Priority Date: 11/10/2009
• Status: Active Grant

• Current Assignee: Mitsubishi Heavy Industries, Ltd.
• Original Assignee: Mitsubishi Heavy Industries, Ltd.
• Inventors: Kawauchi, Naoto, Sasano, Yuichi, Asano, Shin, Kura, Kenji, Matsushita, Hirokazu, Matsumura, Akihiko, Higuchi, Masaru
• Granted Patent: US 8,805,570 B2
• Time in Patent Office: Days
• US Class Current: 700/178
• CPC Class Codes: B23Q 17/20 for indicating or measuring workpiece characteristics, e.g. contour, dimension, hardness
• CPC Class Codes: B23Q 17/2208 Detection or prevention of collisions
• CPC Class Codes: B23Q 17/2471 of workpieces
• CPC Class Codes: G01B 11/24 for measuring contours or curvatures
• CPC Class Codes: G05B 19/4061 Avoiding collision or forbidden zones

Abstract

A workpiece measuring device, a collision preventing device, and a machine tool acquires 3D data of the shape of a workpiece used to prevent a collision between the workpiece and part of the machine tool. A measuring section measures the distance to the workpiece through scanning in a non-contact manner; and a shape recognition section generates a 3D mesh structure. The coordinates of a measurement point on the workpiece based on distance information about the measured distance to the workpiece, and that generates a measurement geometry map such that, when the ratio of the number of times the calculated measurement point is included in one unit of the 3D mesh structure to the number of times a position of the workpiece corresponding to the one unit is scanned is equal to or larger than a predetermined threshold, the one unit is regarded as part of the workpiece are included.

Claims

1. A workpiece measuring device, comprising:

a measuring section that is attached to a main shaft to which a tool used for machining a workpiece serving as an object to be machined is attached and that measures a distance to the workpiece through scanning in a non-contact manner; and

a shape recognition section that generates a 3D mesh structure formed by dividing a space into polyhedrons, that calculates coordinates of a measurement point on the workpiece based on distance information about the measured distance to the workpiece, and that generates a measurement geometry map such that, when the ratio of the number of times the calculated measurement point is included in one unit of the 3D mesh structure to the number of times a position of the workpiece corresponding to the one unit is scanned is equal to or larger than a predetermined threshold, the one unit is regarded as part of the workpiece.

2. A workpiece measuring device according to claim 1, wherein the size of one side of the one unit is set based on the distance between the workpiece and a point at which the tool and the main shaft approaching the workpiece starts machining the workpiece.

3. A workpiece measuring device according to claim 1, wherein the measuring section comprises:

a sensor head that measures the distance to the workpiece through scanning;

a transmission section that transmits the distance information acquired through the measurement with the sensor head;

a battery that supplies electric power to the sensor head and the transmission section; and

a reception section that receives the distance information transmitted from the transmission section and that outputs the received distance information to the shape recognition section.

4. A workpiece measuring device according to claim 1, wherein the measuring section comprises an attachment section that receives electric power supplied via the main shaft and that outputs the measurement information to the shape recognition section via the main shaft.

5. A collision preventing device, comprising:

a workpiece measuring device according to claim 1;

a determination section that determines whether there will be interference between the measurement geometry map and at least one of the main shaft and the tool; and

a control section that controls the movement of the main shaft based on a determination result from the determination section.

6. A machine tool, comprising:

a table on which a workpiece serving as an object to be machined is placed;

a main shaft to which a tool used for machining the workpiece is attached; and

a collision preventing device according to claim 5.