Control of a non-isothermal continuous stirred tank reactor by a feedback–feedforward structure using type-2 fuzzy logic controllers

A control system that uses type-2 fuzzy logic controllers (FLC) is proposed for the control of anon-isothermal continuous stirred tank reactor (CSTR), where a first order irreversiblereaction occurs and that is characterized by the presence of bifurcations. Bifurcations dueto parameter variations can bring the reactor to instability or create new working conditionswhich although stable are unacceptable. An extensive analysis of the uncontrolled CSTRdynamics was carried out and used for the choice of the control configuration and the developmentof controllers. In addition to a feedback controller, the introduction of a feedforwardcontrol loop was required to maintain effective control in the presence of disturbances.Simulation results confirmed the effectiveness and the robustness of the type-2 FLC whichoutperforms its type-1 counterpart particularly when system uncertainties are present.