0
Research Papers

Model-Based Control of Electroslag Remelting Process Using Unscented Kalman Filter

[+] Author and Article Information
Seokyoung Ahn

Department of Mechanical Engineering, University of Texas-Pan American, Edinburg, TX 78539

Joseph J. Beaman

Department of Mechanical Engineering, University of Texas at Austin, Austin, TX 78712

Rodney L. Williamson

 Remelting Technologies, Albuquerque, NM 87112

David K. Melgaard

 Sandia National Laboratories, Albuquerque, NM 87185-1134

J. Dyn. Sys., Meas., Control 132(1), 011011 (Dec 18, 2009) (9 pages) doi:10.1115/1.4000660 History: Received November 06, 2008; Revised October 01, 2009; Published December 18, 2009; Online December 18, 2009

Electroslag remelting (ESR) is used widely throughout the specialty metals industry. The process generally consists of a regularly shaped electrode, wherein a small amount is immersed in liquid slag at a temperature higher than the melting temperature of the electrode. Melting droplets from the electrode fall through the lower density slag into a liquid pool constrained by a crucible and solidify into an ingot. High quality ingots require that electrode melt rate and immersion depth be controlled at all times during the process. This can be difficult when process conditions are such that the temperature distribution in the electrode is not at steady state. This condition is encountered during the beginning and closing stages of the ESR process and also during some process disturbances such as when the melt zone passes through a transverse electrode crack. To address these transient melting situations, a new method of the ESR estimation and control has been developed that incorporates an accurate, reduced order melting model to continually estimate the temperature distribution in the electrode. The ESR process is highly nonlinear, noisy, and has coupled dynamics. An extended Kalman filter and an unscented Kalman filter were chosen as possible estimators and compared in the controller design. During the highly transient periods in melting, the unscented Kalman filter showed superior performance for estimating and controlling the system.

FIGURES IN THIS ARTICLE
<>
Copyright © 2010 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

ESR process schematic

Grahic Jump Location
Figure 2

Energy balance and coordinate setup in the ESR process

Grahic Jump Location
Figure 3

Descriptions of the boundary and immersion depth model of the ESR process

Grahic Jump Location
Figure 4

Plots of the commanded melt rate, melt rate controlled response, and current for case 1 with perfect state estimation

Grahic Jump Location
Figure 5

Plots of the commanded immersion depth, immersion depth controlled response, and ram velocity for case 1 with perfect state estimation

Grahic Jump Location
Figure 6

Plots of the exact and estimated thermal boundary layer thicknesses for case 1 with perfect state feedback

Grahic Jump Location
Figure 7

Plots of the commanded melt rate, melt rate controlled response, and current for case 1 with NLE estimated states

Grahic Jump Location
Figure 8

Plots of the exact and estimated thermal boundary layer thicknesses for case 1 with NLE estimated states

Grahic Jump Location
Figure 9

Plots of the commanded melt rate, melt rate controlled response, and current for case 1 with UKF estimated states

Grahic Jump Location
Figure 10

Plots of the exact and estimated thermal boundary layer thicknesses for case 1 with UKF estimated states

Grahic Jump Location
Figure 11

Plots of the commanded melt rate, melt rate controlled response, and current for case 2 with EKF estimated states

Grahic Jump Location
Figure 12

Plots of the commanded melt rate, melt rate controlled response, and current for case 2 with UKF estimated states

Grahic Jump Location
Figure 13

Plots of the exact and estimated thermal boundary layer thicknesses for case 2 with UKF estimated states

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In