Accession Number : ADA117815

Title :   System Optimization by Periodic Control.

Descriptive Note : Final rept. 1 Oct 76-31 Jan 82,


Personal Author(s) : Gilbert,Elmer G

PDF Url : ADA117815

Report Date : 31 Mar 1982

Pagination or Media Count : 30

Abstract : Research results obtained under the grant are summarized. Contributions to periodic control include: theory, computational methods and applications to aircraft cruise. The theory centers around necessary or sufficient conditions for optimality and gives information on whether or not periodic operation of a dynamic system gives better performance than steady-state operation. The treatment is comprehensive and includes new second-order conditions which have simplified assumptions and incorporate control constraints. Some of these results follow from a new approach to the derivation of higher-order necessary conditions. The approach does not require normality assumptions and has provided other new results, including second-order necessary conditions in optimal control. A method for computing periodic optima is described. It addresses difficulties observed in other approaches and has proved effective in example problems. Optimal aircraft cruise (specific range, endurance, peak altitude) was studied as an application of theoretical and computational techniques. Under special circumstances (e.g., altitude constraints, in low wing loading and drag, high thrust limits), it appears that periodic cruise is significantly better than steady-state cruise. Some research was also done on the theory of nonlinear systems. It includes: functional expansions for input-output maps, conditions for realizability, a backward shift approach to internally bilinear realizations and canonical forms for minimal-order realizations of two-power input-output maps. (Author)

Descriptors :   *Flight control systems, *Optimization, Control theory, Computations, Range(Distance), Endurance(General), Altitude, Aerodynamic loading, Aerodynamic drag, Thrust, Time dependence, Nonlinear systems, Steady state

Subject Categories : Aircraft
      Numerical Mathematics

Distribution Statement : APPROVED FOR PUBLIC RELEASE