Systems and methods for seam tracking in pipe welding

A method for controlling a robotic welding system during automatic welding together of a first weldable section and a second weldable section held in fixed relation to each other by a plurality of stitches at an interface between the first and second weldable sections and mounted on a positioner for rotating the first and second weldable sections in relation to the robotic welding system, the robotic welding system having a robotic arm functionally coupled to a welding torch, a controller for controlling motion of the robotic arm, and a processor operably coupled to the controller, the positioner, and a plurality of sensors including a vision-based sensor positioned to capture images of an area around a welding arc and one or more additional sensors, the method comprising:

• receiving, by the processor, an initiating signal from the controller which causes the robotic welding system to start a welding operation and the positioner to start rotating the first and second weldable sections in relation to the robotic welding system;
• while the positioner is rotating the first and second weldable sections in relation to the robotic welding system, continuously:
• receiving, by the processor, sensor data from the plurality of sensors, the sensor data including images of an interface between the first and second weldable while the welding operation is ongoing;
• processing the sensor data to determine a seam position while the welding operation is ongoing;
• controlling the robotic welding system to move the robotic arm to track the seam position while the welding operation is ongoing;
• processing the sensor data to detect alignment between the welding arc and one of the plurality of stitches while the welding operation is ongoing;
• determining a stitch start in response to detecting a beginning of alignment between the welding arc and the one of the plurality of stitches while the welding operation is ongoing;
• controlling the robotic welding system to adjust welding parameters in response to determining the stitch start while the welding operation is ongoing;
• determining a stitch end in response to detecting an ending of alignment between the welding arc and the one of the plurality of stitches while the welding operation is ongoing;
• and
• controlling the robotic welding system to adjust welding parameters in response to determining the stitch end while the welding operation is ongoing.