Arc welding control system and method

• US 9,468,987 B2
• Filed: 07/06/2011
• Issued: 10/18/2016
• 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
• Application Number:
  US13/881,096
• Publication Number:
  US 20130299475A1
• Time in Patent Office: 1,931 Days
• Field of Search: 219/124.03, 219/124.21
• US Class Current: 1/1
• 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. An arc sensor control system for arc welding for obtaining satisfactory beads in a groove of a workpiece that is a welding target, the arc sensor control system comprising:

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;

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

a calculation unit configured to

obtain 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,

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,

calculate 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, a torch height deviation that is a deviation of the value corresponding to the torch height from the target value, and a first ratio that is a ratio of a degree of influence of the torch height deviation on the manipulated variable of the actuator regarding the weaving width to a degree of influence of the groove wall distance deviation on the manipulated variable of the actuator regarding the weaving width, and

calculate a manipulated variable of the actuator regarding the torch height using the groove wall distance deviation, the torch height deviation, and a second ratio that is a ratio of a degree of influence of the torch height deviation on the manipulated variable of the actuator regarding the torch height to a degree of influence of the groove wall distance deviation on the manipulated variable of the actuator regarding the torch height; and

a control unit configured to control 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;

each of the first and second ratios is set so as to increase as the groove angle increases.

2. The arc sensor control system 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 arc sensor control system according to claim 1, wherein the calculation unit is configured to:

calculate 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;

obtain 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

obtain 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 arc sensor control system 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,