ABSTRACT
Only rarely is it feasible to solve the Hamilton-Jacobi-Bellman partial differential equation for a nonlinear system of any practical significance, and, hence, the development of “exact” explicit feedback guidance and control schemes for nonlinear systems is usually out of reach. However, as mentioned in Chapter 4, perturbation guidance schemes, which involve only those extremal paths in the immediate neighborhood of a nominal extremal path, appear, in many cases, to be feasible. We shall show in Chapter 6 that the perturbation guidance approach leads to a discussion of time-varying linear systems with quadratic performance criteria.
