Retrofiring control method via combination of a 1DoF gimbaled thrust vector control and spin-stabilization

Abstract

In impulsive orbital maneuvers, thrust vector misalignment from the center of mass is the serious source of disturbance torque. A high capacity attitude control system is needed to compensate the mentioned large exogenous disturbance. In this paper a new retrofiring control method is proposed and studied which is based on the combination of a 1DoF gimbaled thrust vector control and spin-stabilization method. Spin-axis stabilization and disturbance rejection are considered as two important attitude control objectives. The nonlinear two-body dynamics of a small spacecraft is derived in which dynamical interaction between the nozzle and the body is significant. Reaction control system is not used and the only active control part is a 1DoF gimbal. The spacecraft design efficiency is very important; therefore, the H∞ performance and control gain norm are chosen as two conflicting cost function in the Pareto front multiobjective optimization. Many Pareto fronts are given for some ranges of two favorable parameters: (1) spin rate and (2) spin-axis moment of inertia. Optimization variables are the closed-loop system poles. Moreover, poles region constraint is employed to obtain a well-damped transient response. From the perspective of performance and design efficiency, the optimization results give many attractive outcomes. The resulting system is an efficient design for a small spacecraft. Furthermore, numerical simulations are included to confirm the optimization results and illustrate the superiority of the proposed method compared to the only spin-stabilization.