Showing papers by "Desineni Subbaram Naidu published in 1995"

Singular perturbations and time scales in guidance, navigation and control of aerospace systems: Survey

Abstract: The theory of singular perturbations and time scales has played an important role in aircraft performance analysis and in the development of feedback guidance laws for aerospace vehicles. This paper presents a survey of the applications of the theory of singular perturbations and time scales in guidance, navigation, and control of air and space transportation systems. In particular, emphasis will be placed on problem formulation and solution approaches that are useful in applying the theory for various types of problems arising in aerospace systems. Fhrther, the survey e m braces the related fields such as fluid dynamics, space structures and space robotics.

Neighboring optimal trajectories for aeroassisted orbital transfer under uncertainties

Abstract: A neighboring optimal guidance scheme is presented for a nonlinear dynamic system in the presence of modeling and measurement uncertainties as applicable to fuel optimal control of an aeroassisted orbital transfer vehicle (AOTV). Here the vehicle is expected to follow a desired reference path with minimum error. The measurements considered include tracking of altitude and altitude rate. The solution approach is based on nonlinear control optimization, deterministic perturbation, stochastic state estimation, and linearized stochastic control that leads to a closed-loop control law. The reference state trajectory and control trajectory are precomputed by solving a two-point boundary-value control problem. Numerical results show that the actual (true) state trajectory is kept near its ideal (reference) state trajectory at the expense of increasing the total cost.