Adaptive Interval Model Control of Arc Welding Process

The welding process is typically uncertain and its dynamics may vary with welding conditions. To control this process, robust algorithms such as the interval model control proposed by Zhang and Kovacevic (1997) are needed. To improve the response speed and system performance, the authors developed an adaptive interval model control system for keyhole plasma arc welding process in this study. The developed system identifies the process parameters online, converts the identification results to the intervals in Zhang and Kovacevic's algorithm (Zhang and Kovacevic 1997), and uses a prefilter to eliminate the effect of the keyhole process' fluctuation on the control system. Experiments comparing the adaptive interval model control system with its nonadaptive counterpart have been conducted to verify the effectiveness of the former in achieving fast response speed when the manufacturing conditions or the set-point vary.