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Nonlinear robust adaptive control strategies for a lactic fermentation process
Author(s) -
Petre Emil,
Selişteanu Dan,
Roman Monica
Publication year - 2018
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.5383
Subject(s) - control theory (sociology) , estimator , continuous stirred tank reactor , residual , adaptive control , process (computing) , computer science , bioprocess , process control , nonlinear system , lactic acid fermentation , robust control , lactic acid , control (management) , mathematics , control system , engineering , algorithm , statistics , artificial intelligence , physics , electrical engineering , quantum mechanics , chemical engineering , biology , bacteria , genetics , operating system
BACKGROUND This work addresses the design of robust adaptive control strategies for a lactic fermentation process carried out inside a continuous stirred tank reactor (CSTR). This bioprocess is widely used in bioindustry for lactic acid production, and it is characterized by strong nonlinearities and uncertainties. Under the realistic assumption that the reaction kinetics and the influent flow rates are unknown and time‐varying, but lower and upper bounds of the uncertainties are known, two innovative robust adaptive control structures are proposed. RESULTS The control strategies are designed by combining a linearizing control law with two novel parameter estimators able to estimate the unknown reaction rates. The first strategy uses a modified observer based estimator and the second one utilizes an interval parameter estimator. The control objective is to adjust the plant load so as to convert the glucose into lactic acid via fermentation, which is directly correlated with the economic aspects of lactic acid production. Numerical simulations are performed in order to validate the proposed solution. CONCLUSION By using the proposed control strategies the process is maintained at certain operating points that correspond to a maximum lactic production rate and a minimal residual glucose concentration. The simulations performed by considering various uncertainties and noisy measurement data show that the proposed novel robust adaptive controllers are suitable to control this kind of fermentation processes. © 2017 Society of Chemical Industry