WELDING TORCH DETECTOR AND WELDING ROBOT SYSTEM

• US 20150246406A1
• Filed: 02/27/2015
• Published: 09/03/2015
• Est. Priority Date: 02/28/2014
• Status: Active Grant

• Current Assignee: Fanuc Corporation
• Original Assignee: Fanuc Corporation
• Inventors: TAKAYAMA, Yuusuke
• Granted Patent: US 10,016,834 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B23K 9/0956 using sensing means, e.g. optical
• CPC Class Codes: B23K 9/173 and of a consumable electrode
• CPC Class Codes: B23K 9/32 Accessories earthing connections H01R

Abstract

A welding torch detector including an imaging unit capturing images of a welding torch and welding wire from a plurality of directions to acquire image signals, an image recognition unit recognizing welding wire images and welding torch images based on the image signals acquired, a setting unit setting a target point corresponding to a target position of the welding wire on the welding wire images recognized, a position detection unit detecting a position of the target point in a three-dimensional space based on the welding wire images recognized, and an inclination detection unit detecting an inclination of the welding torch in the three-dimensional space based on the welding torch images recognized.

Claims

1. A welding torch detector comprising:

an imaging unit configured to capture images of a welding torch provided at an arm tip part of a welding robot and a welding wire fed from the welding torch from a plurality of directions, and acquire image signals of the welding torch and the welding wire;

an image recognition unit configured to recognize, based on the image signals acquired by the imaging unit, a plurality of welding wire images representing the welding wire seen from the plurality of directions and a plurality of welding torch images representing the welding torch seen from the plurality of directions;

a setting unit configured to set a target point corresponding to a target position of the welding wire on the plurality of welding wire images recognized by the image recognition unit;

a position detection unit configured to detect, based on the plurality of welding wire images recognized by the image recognition unit, a position of the target point in a three-dimensional space; and

an inclination detection unit configured to detect, based on the plurality of welding torch images recognized by the image recognition unit, an inclination of the welding torch in the three-dimensional space.

2. The welding torch detector according to claim 1, wherein the inclination of the welding torch is represented by a three-dimensional orthogonal coordinate system used for position control of the welding robot at the target point.

3. The welding torch detector according to claim 1, wherein the setting unit sets, as the target point, an intersection point between a circular arc having a predetermined radius around a tip of the welding torch image recognized by the image recognition unit and the welding wire image.

4. The welding torch detector according to claim 1, wherein the setting unit sets, as the target point, an intersection point between a virtual line away by a predetermined distance from a tip of the welding torch image recognized by the image recognition unit along a center line of the welding torch image and the welding wire image.

5. A welding robot system comprising:

the welding torch detector according to claim 1;

a torch moving unit configured to move the welding torch;

a wire feeding unit configured to feed the welding wire from the welding torch; and

a control unit configured to control the torch moving unit, the wire feeding unit, and the imaging unit,

wherein the control unit controls the imaging unit to capture images of the welding torch and the welding wire from a plurality of directions.

6. The welding robot system according to claim 5, further comprising a wire determination unit configured to determine whether the image recognition unit has recognized the welding wire image within a predetermined range,

wherein the control unit controls the wire feeding unit to feed the welding wire when the wire determination unit determines that the welding wire image within the predetermined range has not been recognized, and controls the imaging unit to capture images of the welding torch and the welding wire after the wire feeding unit feeds the welding wire.

7. The welding robot system according to claim 5, further comprising a torch determination unit configured to determine whether the image recognition unit has recognized the welding torch image within a predetermined range,

wherein the control unit controls the torch moving unit to move the welding torch toward an imaging region when the torch determination unit determines that the welding torch image within the predetermined range has not been recognized, and controls the imaging unit to capture an image of the imaging region after the torch moving unit moves the welding torch.

8. The welding robot system according to claim 5, further comprising a correction unit configured to correct pre-instructed command values of a position and inclination of the target point by using the position detected by the position detection unit and the inclination detected by the inclination detection unit.

9. The welding robot system according to claim 8, wherein,

the control unit controls the torch moving unit and the imaging unit to move the welding torch to a predetermined position to acquire image signals of the welding torch and the welding wire at a first time point and a second time point after a predetermined time elapses from the first point time, and

when a position of the target point detected by the position detection unit and inclination of the welding torch detected by the inclination detection unit at the first time point are deviated from a position of the target point detected by the position detection unit and inclination of the welding torch detected by the inclination detection unit at the second time point, the correction unit corrects the command values based on an amount of the deviation.