Optimization and control of a fedbatch fermentation process

This paper describes the optimization problem of a fedbatch fermentation process for alcohol production which initially consists of minimizing a time-optimal global criterion. Dynamic programming methods have previously allowed one to solve this global optimziation problem and to deduce a local criterion to be maximized at each sampling step by using non-linear programming techniques. It is then stated that under a few realistic constraints the optimization problem can be translated into the regulation problem of the substrate concentration in the fermentor. The optimal value is a function of a certain growth model. A control law based on the quotient between measurement and optimal value is then implemented. Simulation results and real-life experiments validate the problem transformation.