Optimal bifurcation tailoring based transition control of reactor separation recycle systems

A novel method for transition control of nonlinear processes is presented. Gain scheduling is implemented to ensure stability and desired output behavior over the operating region of interest while transition between the initial and the final equilibrium is achieved by predictive reference control. In this framework, the search of a feasible reference input sequence is performed so that the closed-loop system moves along an optimal curve of equilibria. This curve is computed off-line so that its points lye far from the border of the process constraint set and correspond to satisfactory controllability of the uncontrolled plant. Moreover, bifurcation analysis of the closed loop system is carried out providing valuable indications on how to select controller parameter values preventing transition to undesired solution regimes. Effectiveness of the method is shown by application to the problem of controlling the start-up of a reactor separation recycle system. © 2009 Elsevier B.V. All rights reserved.