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.

Gimbaled-thruster based nonlinear attitude control of a small spacecraft during thrusting manoeuvre

“…A gimbaled TVC can be also employed for a solar-sail spacecraft (32) . The gimbaled nozzle (gimbaled thruster) can be very useful in preserving weight, simplifying the attitude control system and reducing the requirements of the CM positioning accuracy (3,4,28) . It should be noted that in large and massive spacecraft or launchers with a liquid propellant rocket, several heavy and complex components as well as fuel tanks are located in the body not presented (or attached) at the rotatable nozzle.…”

“…Some equipment such as thrusters and fuel tanks are needed for spin-up and spin-down (3) . 4. In some works such as in , the resonance in the spacecraft devices created by the nutation is addressed.…”

“…In addition to the methods presented in Ref. 3, a novel method is proposed in Ref. 4 where the combination of the TVC scheme and spin-stabilisation is formulated and investigated.…”

“…It is obvious that using a liquid propellant rocket is not efficient or possible for a small spacecraft for which a SRM (solid rocket motor) is used where all mass properties of the SRM (including solid fuel) will be added to the nozzle mass properties. Therefore, for a small spacecraft equipped with a SRM, the aforementioned interaction cannot be neglected and leads to nonlinear two-body dynamics (4,28,33) . Note that for large spacecraft, a TVC was used together with RCSs (1,18,26,27) and for a small spacecraft, it has been combined with the spin-stabilisation method (4) .…”

“…Therefore, for a small spacecraft equipped with a SRM, the aforementioned interaction cannot be neglected and leads to nonlinear two-body dynamics (4,28,33) . Note that for large spacecraft, a TVC was used together with RCSs (1,18,26,27) and for a small spacecraft, it has been combined with the spin-stabilisation method (4) . Although in Felicetti et al (34) , an adaptive thrust vector control during on-orbit servicing is addressed, the interaction dynamics between the nozzle and the body is not considered as well, because it is not applicable for an impulsive orbital manoeuvre.…”