Multi-agent model predictive control for transport phenomena processes

Throughout the last decades, control systems theory has thrived, promoting new areas of development, especially for chemical and biological process engineering. Production processes are becoming more and more complex and researchers, academics and industry professionals dedicate more time in order to keep up-to-date with the increasing complexity and nonlinearity. Developing control architectures and incorporating novel control techniques as a way to overcome optimization problems is the main focus for all people involved. Nonlinear Model Predictive Control (NMPC) has been one of the main responses from academia for the exponential growth of process complexity and fast growing scale. Prediction algorithms are the response to manage closed-loop stability and optimize results. Adaptation mechanisms are nowadays seen as a natural extension of prediction methodologies in order to tackle uncertainty in distributed parameter systems (DPS), governed by partial differential equations (PDE). Parameters observers and Lyapunov adaptation laws are also tools for the systems in study. Stability and stabilization conditions, being implicitly or explicitly incorporated in the NMPC formulation, by means of pointwise min-norm techniques, are also being used and combined as a way to improve control performance, robustness and reduce computational effort or maintain it low, without degrading control action. With the above assumptions, centralized (or single agent) or decentralized and distributed Model Predictive Control (MPC) architectures (also called multi-agent) have been applied to a series of nonlinear distributed parameters systems with transport phenomena, such as bioreactors, water delivery canals and heat exchangers to show the importance and success of these control techniques

Computer-based studies on bioprocess engineering : II - Tools for process operation

In this paper we review recent advances on the practice and theory of process control with particular emphasis to the operation of bioreactors. We present in detail a case-study on the modelling, model-based identification and adaptive control of fed-batch baker's yeast fermentation.Junta Nacional de Investigação Científica e Tecnológica (JNICT) - contract numbers BD/224/90-IF, BD/1476/91-RM.Instituto Nacional de Investigação Científica (INIC)

Towards flatness of a fixed bed bioreactor

The fixed bed bioreactor is modelised by a non linear hyperbolic system of partial differential equations. This mode! is considered in an aim of control by the flowrate at the input of the reactor. We propose to design this control law by pointing out a fiat output for the studied process, the property of flatness insuring then the tracking of a given trajectory