On Optimal and Suboptimal Policies in Control Systems

Abstract

Publisher Summary This chapter focuses on the optimal and suboptimal policies in control systems. Optimal control policies may be given as a function of state of the control systems or as a function of time. They represent closed-loop control of the system in the former case and represent open-loop control in the latter. The way of controlling the system in some nonoptimal way for the given criterion of performance is called a suboptimal control policy. Because of the scale and complexity of systems, it may not be possible to solve optimal control problems exactly even if optimal policies are assumed to exist, or, for that matter, optimal policies may not exist. Also, if optimal policies whose existences are assumed are too complex either from the viewpoint of analysis or engineering implementation, then various approximate solutions of the optimal control problems must be considered. The chapter presents sufficient conditions for the existence of optimal control and the problem of controlling systems where optimal controls do not exist.