Fractal measures in control performance assessment
Paweł D. Domański · 2016
In case of numerous loops control engineers need fast and accurate method finding out loops with the poorest control quality. There exits several measures however, industrial practice reveals their deficiencies. Some of them require introduction of external disturbance into the process (like the step test) that in many cases is considered as a risk or threat. The other group of automatic approaches uses regular process data and is based on the loop Gaussian properties foundation. Analysis of real process data shows that this assumption holds only in a few cases. Both facts initiated research for alternative measures grouped into statistical non-Gaussian indexes and fractal ones based on the properties of R/S plot and Hurst index. The analysis is performed on both simulation and real industrial data revealing interesting properties and proving validity of selected approach.