Robust nonlinear extended prediction self-adaptive control (NEPSAC) of continuous bioreactors

A nonlinear predictive control strategy (NEPSAC) is formulated for a continuous bioreactor characterized by severe non-linearity and parameter time-variance, with the control objective being to regulate the fermenter operation near the optimum productivity. Robustness towards the unpredictable time-variance, which comes from cell-mass growth, is guaranteed by disturbance filter design. The dilution rate and feed substrate concentration are considered as manipulated inputs, while the state variables are the biomass, substrate and product concentrations. Results obtained with robust NEPSAC are presented and compared with those obtained with other model predictive control and various linearization based strategies.