Lateral separation dynamics and stablility of a two-stage hypersonic vehicle

This paper presents results from an investigation on lateral dynamics and stability of a two-stage hypersonic flight system during the separation maneuver. Based on aerodynamic data from wind tunnel tests conducted at the Institute of Theoretical and Applied Mechanics (ITAM) of the Russian Academy of Sciences, Siberian Branch, Novosibirsk, a simulation model was developed for investigating the aerodynamically coupled flight system with respect to stability. Stability deficiencies of both vehicles are shown in different flight conditions as well as during separation with aerodynamic coupling. The results reveal that the aerodynamic interference does not only affect longitudinal but also lateral dynamics, particularly with regard to the upper stage. Dependences of aerodynamic forces and moments of the relative roll angle of the vehicles induce unique eigen modes of the upper stage. Recognizing flying qualities requirements, a flight control system is developed for the two vehicles for stabilizing and safely performing the separation maneuver. For this purpose, modern methods of control system design are used. For validation of the flight control system, nonlinear numerical simulations of the separation maneuver are conducted.