Arc welding control system and method

• US 10,144,081 B2
• Filed: 12/08/2015
• Issued: 12/04/2018
• Est. Priority Date: 10/26/2010
• Status: Active Grant

• Current Assignee: Kawasaki Jukogyo Kabushiki Kaisha
• Original Assignee: Kawasaki Jukogyo Kabushiki Kaisha
• Inventors: Aoki, Atsuhito, Takeichi, Masatsugu, Seto, Masaru, Ikezawa, Yukio
• Primary Examiner(s): Ross, Dana
• Assistant Examiner(s): MAYE, AYUB A
• Application Number:
  US14/962,767
• Publication Number:
  US 20160107255A1
• Time in Patent Office: 1,092 Days
• Field of Search: 21912402, 21912403, 2191241, 21912421, 21912432, 21912433, 21912434
• CPC Class Codes: B23K 9/0216 Seam profiling, e.g. weaving, multilayer
• CPC Class Codes: B23K 9/09 Arrangements or circuits for arc welding with pulsed current or voltage
• CPC Class Codes: B23K 9/095 Monitoring or automatic control of welding parameters
• CPC Class Codes: B23K 9/0953 using computing means
• CPC Class Codes: B23K 9/0956 using sensing means, e.g. optical
• CPC Class Codes: B23K 9/127 Means for tracking lines during arc welding or cutting copying in general B23Q35/00

Abstract

The present invention provides an arc welding control system and method capable of simultaneously, sophisticatedly performing a weaving width control operation and a torch height control operation. Influence ratios (δ_w and δ_z) of influences of a torch height deviation (ΔP_h) and a groove wall distance deviation (ΔP_d) with respect to a manipulated variable (Δw) of a weaving width and a manipulated variable (Δz) of a torch height are set in accordance with a groove angle (θ) of a workpiece (5). A calculation unit (21) calculates the manipulated variables (Δz and Δw) of actuators (13 and 14) regarding the torch height and the weaving width such that the influence ratios (δ_w and δ_z) become large as the groove angle (θ) becomes large.

Claims

1. A method of controlling an arc sensor for arc welding for obtaining beads in a groove of a workpiece that is a welding target, the method utilizing:

an actuator configured to cause a welding torch to track a weld line of the workpiece by causing the welding torch to move in a direction of the weld line of the workpiece at a specified torch height while causing the welding torch to move in a cyclic manner in a width direction of the groove of the workpiece with a specified weaving width; and

a sensor configured to detect a welding current or an arc voltage,

the method comprising the steps of;

detecting the welding current or the arc voltage;

obtaining from the welding current or the arc voltage a value corresponding to a groove wall distance indicating a horizontal distance between the welding torch and the workpiece at a weaving end portion and a value corresponding to the torch height to calculate a difference between the value corresponding to the groove wall distance and a target value and a difference between the value corresponding to the torch height and a target value;

calculating a manipulated variable of the actuator regarding the weaving width using a groove wall distance deviation that is a deviation of the value corresponding to the groove wall distance from the target value and a torch height deviation that is a deviation of the value corresponding to the torch height from the target value, and

calculating a manipulated variable of the actuator regarding the torch height using the groove wall distance deviation and the torch height deviation; and

controlling the weaving width and the torch height based on the manipulated variable regarding the weaving width and the manipulated variable regarding the torch height, wherein;

a first ratio that is a ratio of a degree of an influence of the groove wall distance deviation with respect to each of the manipulated variable of the weaving width and the manipulated variable of the torch height and a second ratio that is a ratio of a degree of an influence of the torch height deviation with respect to each of the manipulated variable of the weaving width and the manipulated variable of the torch height are set in accordance with a groove angle of the workpiece; and

the first ratio and the second ratio are set such that as the groove angle becomes large, the second ratio becomes relatively larger than the first ratio.

2. The method according to claim 1, wherein the manipulated variable of the actuator regarding the weaving width is obtained by multiplying the first ratio by an adjustment coefficient for adjusting the first ratio, and the manipulated variable of the actuator regarding the torch height is obtained by multiplying the second ratio by an adjustment coefficient for adjusting the second ratio.

3. The method according to claim 1, further comprising the steps of:

calculating an average value of the welding current or arc voltage for each of a plurality of sections of one weaving cycle, the welding current or arc voltage being detected by the sensor, the plurality of sections being obtained by dividing one weaving cycle into a predetermined number;

obtaining the value corresponding to the groove wall distance based on the average value of one or a plurality of sections corresponding to the weaving end portion among the plurality of sections; and

obtaining the value corresponding to the torch height based on the average value of the welding current or arc voltage of one weaving cycle.

4. The method according to claim 2, wherein:

a manipulated variable Δ

z of the torch height is represented by Formula 1 below; and

a manipulated variable Δ

w of the weaving width is represented by Formula 2 below,