A New Nonlinear Adaptive Approach to Automatic Control of Bioprocesses

In this paper we present a nonlinear adaptive approach of L/A type to control fermentation processes. The basic idea is to operate on an elementary nonlinear relation (ratio: set-point/output) instead of a linear one (difference: set point - output) and to use the power of the ratio as a (self)tuning parameter of the control algorithm. Algorithms, able to control biomass and substrate concentrations, are obtained. In a simple way they take into account basic physical limits of the real process (i.e. positivity of control and state variables). Their minimal formulation and tuning simplicity facilitate the application and computer implementation.