OPTIMIZATION OF AEROSPACE SYSTEM CONTROL WITH CONSTRAINTS ON RETURN TRAJECTORIES OF SPENT ELEMENTS

摘要

Optimal injection control problem for different-type space transport systems (STS) is considered. A specific feature of the problem statement is the application of the strict indirect optimization method based on the Pontryagin maximum principle with due regard for a branched trajectory behavior and practical constraints at all injection stages. The automated program package ASTER for thorough STS injection optimization under this statement is described. Emphasis is placed on qualitatively new effects in the behavior of optimal solutions and on potentialities of increasing the injected mass both of new and existing STS configurations. Also, the existence of several qualitatively-different extremal types, a bifurcation nature of changes in optimal control programs, trajectories and influence functions in a practical range of STS parameters are demonstrated with variations of STS parameters. This nonlinear analysis of optimal trajectories and control laws is carried out thanks to the advantages of the used indirect optimization method and the regularity of solution procedures for multipoint boundary-value problems and extremal selection realized in ASTER. As examples, the results of thorough injection optimization are presented for: 1. STS consisted of a subsonic carrier aeroplane and a launch vehicle (rocket) inside it; 2. "Proton"-type launch vehicle with constraints on spent boosters and fairing fall zones; 3. aerospace plane with hybrid powerplant.