Author/Authors :
Alexander Horch and Alf J. Isaksson، نويسنده ,
Title Of Article :
A modified index for control performance assessment
Latin Abstract :
A control performance index which relates actual output variance to minimal achievable variance was ®rst presented by Harris
[T.J. Harris, Assessment of control loop performance, The Canadian Journal of Chemical Engineering 67 (1989) 856±861]. In the
present paper, a modi®cation of that index is applied. Instead of comparing to minimum variance controlÐwhich corresponds to
placing all closed-loop poles in the originÐone pole is placed using either control design guidelines or additionally available pro-
cess knowledge. Some possible choices of the free closed-loop pole are discussed. Based on this modi®ed closed-loop system, a
performance index can be calculated which relates actual output variance to the minimum achievable variance using the modi®ed
closed-loop system. It is shown that for the calculation of this index no other information apart from the measured process output
and the time-delay is necessary. Furthermore, a method is presented which allows the assessment of the accuracy of the calculated
index. The original Harris index and the proposed modi®ed index are computed using data from industrial processes.
NaturalLanguageKeyword :
Control performance monitoring , minimum variance control , Pole placement , Robustness , Standard deviation
JournalTitle :
Studia Iranica
