Classic Methodologies in Control of a Yeast Fermentation Bioreactor

In this article, a comparison between different PID controllers and MPC on a yeast fermentation reactor model is addressed. PID controllers with and without anti-wind-up are considered. The bioreactor model is a non-linear model with seven states and four inputs that can be reduced to a SISO system using constant input and output flows. Different performance criteria have been taken into account, such as the mean square error (MSE), maximum error (ME), ITAE among others. To emulate more realistic conditions, some modifications were made to the model, such as constraints additions. There was not found a unique best control strategy for all criteria, but rather a local winner for strategy. This leads to the final conclusion that even when the PID belongs to one of the oldest control strategies, it is still competitive with modern strategies in SISO paradigms.