Control of 3D weld pool surface

• The characteristic parameters of the 3D weld pool surface in GTAW process is measured in real-time by an innovative machine vision system.
• The correlation between characteristic parameters and welding current/speed as control variables is modeled.
• A predictive control algorithm is developed to control the characteristic parameters in a closed form without the need for online optimization.
• Welding experiments confirm that the developed control system is effective in achieving the desired 3D weld pool surface geometry despite various disturbances.

The 3D weld pool surface in gas tungsten arc welding (GTAW) is characterized by its width, length, convexity and measured in real-time using an innovative machine vision system. The dynamic response of these characteristic parameters to welding current and speed as control variables is modeled. Based on the identified dynamic model, a predictive control algorithm is developed to control these characteristic parameters. The proposed algorithm is given in a closed form and no online optimization is required. Welding experiments confirm that the developed control system is effective in achieving the desired 3D weld pool surface geometry despite various disturbances.