In this research, double-command control of a nonlinear chemical system is addressed. The system is a stirred tank reactor; two flows of liquid with different concentrations enter the system through two valves and another flow exits the tank with a concentration between the two input concentrations. Fuzzy logic was employed to design a model-free double-command controller for this system in the simulation environment. In order to avoid output chattering and frequent change of control command (leading to frequent closing-opening of control valves, in practice) a
damper rule is added to the fuzzy control system. A feedforward (steady state) control law is also derived from the nonlinear mathematical model of the system to be added to feedback (fuzzy) controller generating transient control command. The hybrid control system leads to a very smooth change of control input, which suits real applications. The proposed control system offers much lower error integral, control command change and processing time in comparison
with neuro-predictive controllers.
Mohammadzaheri M, Chen L, Efficient intelligent nonlinear predictive control of a chemical plant, 15th International Conference on Neural Information Processing of the Asia-Pacific Neural Network Assembly, November 25-28, Auckland, New Zealand, 2008
Tan Y, Van Cauwenberghe AR, Neurocomputing, 10, 83, 1996
Jang JR, Sun C, Mizutani E, Neuro-fuzzy and soft computing, Prentice-Hall of India, New Delhi, 2006
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