A 6-DOF extended state observer–based adaptive generalized super twisting algorithm of fault-tolerant control for coupled spacecraft with actuator saturation

Abstract

This paper aims to address an integrated relative attitude and position fault-tolerant control strategy between a follower spacecraft and a leader spacecraft for coupled spacecraft tracking maneuver in the case of inertia parametric uncertainties, external disturbances, actuator failures, and saturation. The coupled rotational and translational kinematics and dynamics of the rigid spacecraft are derived on the Lie group SE(3), where the actuator failures and saturation are taken into account. Then, a 6-DOF extended state observer is proposed by using terminal sliding mode technique to estimate the lumped disturbance in finite time. An adaptive generalized super twisting algorithm of fault-tolerant controller is developed to guarantee the finite-time stability based on the estimated lumped disturbance information. The stability of the closed-loop system is proved in spite of the aforementioned disturbances via the Lyapunov analysis. Finally, the numerical simulation illustrates the effectiveness of the proposed control strategy.

Feasibility analysis and saturation control for underactuated spacecraft formation reconfiguration in elliptic orbits

“…The common approaches to solve the input saturation problem can be divided into two ways. [29][30][31][32][33][34] One way is to smooth the input signal by constructing a Gaussian error function or a hyperbolic tangent function. 35 Another idea is to design an auxiliary system to compensate for input constraint, in which the auxiliary system is mainly driven by the difference between the maximum output of the thruster and the actual control signal.…”

“…However, most existing input saturation control schemes are not applicable to underactuated systems. [29][30][31][32] Huang and Yan 21 noted that the input saturation constrained the hovering position of the follower and developed the saturation controllers for either underactuated case. Notably, the input saturation problem with timeinvariant and time-varying coefficients separation in the underactuated time-varying system remains to be solved.…”