Dynamic modeling and adaptive control of the gas metal arc welding process

Jae Bok Song, David E. Hardt

    Research output: Contribution to journalArticlepeer-review

    45 Citations (Scopus)

    Abstract

    Control of the welding process is a very important step in weldingautomation. Since the welding process is complex and highly nonlinear, it is very difficult to accurately model the process for real-time control. In this research, a discretetime transfer function matrix model for gas metal arc welding process is proposed. This empirical model takes the common dynamics for each output and inherent process and measurement delays into account. Although this linearized model is valid only around the operating pointof interest, the adaptation mechanism employed in the control system renderthis model useful over a wide operating range. Since welding is inherently a nonlinear and multi-input, multi-output process, a multivariable adaptivecontrol system is used for high performance. The process outputs consideredare weld bead width and depth, and the process inputs are chosen as the travel speed of the torch and the heat input. A onestep- ahead (or deadbeat) adaptive control algorithm combined with a recursive least-squares methods for on-line parameter estimation is implemented in order to achieve the desired weld bead geometries. Control weighting factors are used to maintain the stability and reduce excessive control effort. Some guidelines for the control design are also suggested. Command following and disturbance rejection properties of the adaptive control system for both SISO and MIMO cases are investigated by simulation and experiment. Although a truly independent control of the outputs is difficult to implement because of a strong output coupling inherent in the process, a control system for simultaneous controlof bead width and depth was successfully implemented.

    Original languageEnglish
    Pages (from-to)405-413
    Number of pages9
    JournalJournal of Dynamic Systems, Measurement and Control, Transactions of the ASME
    Volume116
    Issue number3
    DOIs
    Publication statusPublished - 1994 Sept

    ASJC Scopus subject areas

    • Control and Systems Engineering
    • Information Systems
    • Instrumentation
    • Mechanical Engineering
    • Computer Science Applications

    Fingerprint

    Dive into the research topics of 'Dynamic modeling and adaptive control of the gas metal arc welding process'. Together they form a unique fingerprint.

    Cite this