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Deadtime compensation for nonlinear processes
Author(s) -
Kravaris Costas,
Wright Raymond A.
Publication year - 1989
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690350914
Subject(s) - control theory (sociology) , nonlinear system , compensation (psychology) , multiplicative function , linear system , controller (irrigation) , observer (physics) , feedback loop , process (computing) , computer science , stability (learning theory) , control system , nonlinear control , control engineering , mathematics , control (management) , engineering , physics , artificial intelligence , psychology , mathematical analysis , computer security , electrical engineering , quantum mechanics , machine learning , psychoanalysis , agronomy , biology , operating system
Many industrially important processes feature both nonlinear system dynamics and a process deadtime. Powerful deadtime compensation methods, such as the Smith predictor structure in state space for linear systems is presented first and then directly extended to nonlinear systems. When combined with input/output linearizing state feedback, this Smith‐like predictor makes a nonlinear system with deadtime behave like a linear system with deadtime. The control structure is completed by adding an external linear controller, which provides integral action and compensates for the deadtime in the input/output linear system, and an open‐loop state observer. Conditions for robust stability with respect to errors in the deadtime and more general linear unstructured multiplicative uncertainties are given. Computer simulations for an example system demonstrate the high controller performance that can be obtained using the proposed method.