Arc welding control system and method

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 from a deviation (hereinafter referred to as a “groove wall distance deviation”) of the value corresponding to the groove wall distance from the target value and a deviation (hereinafter referred to as a “torch height 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 from 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 ratio (hereinafter referred to as an influence ratio) 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 ratio (hereinafter referred to as an influence ratio) 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 influence ratio of the groove wall distance deviation and the influence ratio of the torch height deviation are set such that as the groove angle becomes large, the influence ratio of the torch height deviation becomes relatively larger than the influence ratio of the groove wall distance deviation.