Stiction Quantification based on Time and Frequency Domain Criterions

Abstract

Valve stiction is one of the most common causes for poor performance in industrial control loops. Therefore, a non-invasive method which can detect and quantify stiction is urgently needed in the process industry. Most of the current stiction estimation methods use time domain criterion, e.g. Mean Square Error, to jointly identify the stiction and process model parameters. However, stiction induced oscillation is a phenomenon which has some specific characteristics in the frequency domain. Thus, extracting frequency domain information in the routine operation data will provide a more reliable and accurate stiction estimation. In this work, under the framework of Hammerstein model identification and global optimization, a new stiction quantification method based on time and frequency domain criterions is proposed. Several simulation case studies are demonstrated to validate the proposed method.