RCS and Aero Surfaces Control Allocation Research on RLV’s Re-Entry Phase

Abstract

Based on the characteristics of aero surfaces and reaction control system (RCS), a control allocation scheme is needed to specify aero surface deflections and RCS thruster’s firing commands, during the re-entry phase of reusable launch vehicle (RLV). To analyze the control performance differences introduced by different allocation algorithms, this paper presents a proportional allocation scheme based on dynamic pressure, a daisy-chaining allocation scheme based on the control error, and a multi-object-based optimal allocation scheme, to deal with the allocation problem of RCS and aero surfaces. The first allocation scheme is the simplest, and the second one is more complicated, when considering the actuators’ physical constraints in the allocation problem. The third scheme not only takes the physical constraints into account, but also the rate constraints, and other constraints of RCS and aero surfaces, while for the objective optimization function, not like the single-object function of the other two schemes, it combines the allocation error minimization, fuel consumption minimization, and other functions, with the adaptive weight values. After the stability analysis, the feasibility of the aforementioned allocation schemes are verified by the simulation, and the contrastive analysis of their control performances are followed.