US 5,171,966 AGranted

Method of and apparatus for controlling a welding robot

AssigneesShin Meiwa Industry Co., Ltd., Hitachi Construction Machinery Co., Ltd.

InventorsHisahiro Fukuoka, Yutaka Takano, Yoichi Kamiyama

Life of this patent

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Abstract

A welding torch (4) of a welding robot (RO) is supported by arms (2, 3), to be movable under control by a computer (7). When first and second members (W1, W2) are welded by a weld woven across an interspace between them while oscillating a welding torch (4) along a weld line (WL). Data on changes in the interspace between the first and second welded member (W1, W2) along direction of the weld line (WL) are previously stored in advance to welding. During the welding, the computer 7 performs arithmetic to obtain command values on the basis of the data to output the same to the welding robot (RO), so that the welding robot (RO) performs weaving in accordance with the command values while varying a weaving amplitude of the welding torch (4) in response to the change in the interspace. Changes in the direction in which the welding torch is moved to weave the weld are determined by detecting the actual value of the welding current and reversing direction when the detected value exceeds a prescribed threshold value.

Claims4

Dependent claims

A method of controlling a welding robot (RO) for welding first and second welded members (W1, W2) by moving a welding torch energized by a welding current and held by robot arms for movably supporting said welding torch while oscillating said welding torch in a first direction substantially perpendicular to a weld line (WL) and in a second direction substantially opposite to said first direction, said method comprising the steps of:

moving said welding torch in said first direction while detecting a magnitude of said welding current;
changing the direction of movement of said welding torch from said first direction to said second direction when said detected magnitude of said welding current exceeds a prescribed threshold value;
moving said welding torch in said second direction while detecting said welding current;
and
changing the direction of movement of said welding torch from said second direction to said first direction when the magnitude of said welding current detected in said third step exceeds said prescribed threshold value,
said previous steps being repeated in order to make said welding robot (RO) perform controlled weaving and welding while varying a weaving amplitude between said first and second welded members (W1, W2) within a range of movements within which said detected magnitude of said welding current is lower than said prescribed threshold value.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/784,186Filed 29 Oct 1991 · division
Priority: JP 61-6256120 Mar 1986
Granted: 15 Dec 1992
Term ends: Not estimatedThe source records don’t support an estimate.

Classification12 codes

G05B 19/425
Recording and playback systems, i.e. in which the program is recorded from a cycle of operations, e.g. the cycle of operations being manually…:…
B23K 9/0216
Seam welding; Backing means; Inserts: seam profiling, e.g. weaving, multilayer
B23K 9/1272
Means for tracking lines during arc welding or cutting: geometry oriented, e.g. beam optical trading
B25J 9/1679
Program controls: characterised by the tasks executed

Family

Serial138,383Parent of this division · filed 20 Nov 1987
Serial393,746Parent of this division · filed 6 Sep 1989
US 5,075,533 AParent of this division
US 4,870,247 AParent of this division
US 5,171,966 AThis patent

From the US filing history. Foreign family members aren’t listed.