ON THE COMPUTATION OF OPTIMAL SINGULAR AND BANG-BANG CONTROLS

To avoid difficulties associated with the computation of optimal singu lar/bang-bang controls, a common approach is to add a perturbed energy term. The efficacy of this perturbation method is assessed here via a direct search iterative dynamic programming procedure. A potential li mitation of the strategy is shown from a computational point of view, and some guidelines for selecting the perturbation parameter are provi ded using numerical examples. It is demonstrated that many gradient-ba sed methods may not be well suited for computing singular/bang-bang co ntrols when perturbation methods are used to solve optimal control pro blems in chemical process control. (C) 1998 John Wiley & Sons, Ltd.