Considering the large-scale communication delays mainly caused by the large detection arm length with several million kilometers in the heliocentric gravitational-wave detection mission, the attitude-orbit coordinated control issue is addressed in this work. Firstly, to describe the formation detection motion in the Sun–Earth system, an attitude-orbit coupled relative motion model of the formation spacecraft is established with the assistance of a virtual structure. Then, a comprehensive model of communication delays caused by the large detection arm length and hardware resource constraints is constructed. Next, to realize the fast convergence of the formation attitude-orbit errors, a reliable and robust integration design of attitude-orbit coordinated control protocol is elaborated by delay-dependent Lyapunov function, in which the unknown lumped disturbances and the aftereffects of large-scale communication delays are suppressed with the adaptive control item and the delay-effect compensation one, respectively. Finally, numerical simulations are constructed with the typical heliocentric gravitational-wave detection mission scenario, verifying the validity and superiority of the proposed method with the existing findings as a comparison.

This paper investigates an analytical optimal pose tracking control problem for chaser spacecraft during the close-range proximity operations with a non-cooperative space target subject to attitude tumbling and unknown orbital maneuvering. Firstly, the relative translational motion between the orbital target and the chaser spacecraft is described in the Line-of-Sight (LOS) coordinate frame along with attitude quaternion dynamics. Then, based on the coupled 6-Degree of Freedom (DOF) pose dynamic model, an analytical optimal control action consisting of constrained optimal control value, application time and its duration are proposed via exploring the iterative sequential action control algorithm. Meanwhile, the global closed-loop asymptotic stability of the proposed predictive control action is presented and discussed. Compared with traditional proximity control schemes, the highlighting advantages are that the application time and duration of the devised controller is applied discretely in light of the influence of the instantaneous pose configuration on the pose tracking performance with less energy consumptions rather than at each sample time. Finally, three groups of illustrative examples are organized to validate the effectiveness of the proposed analytical optimal pose tracking control scheme.

For the challenging problem that a spacecraft approaches a tumbling target with non-cooperative maneuver, an anti-saturated proximity control method is proposed in this paper. First, a brand-new appointed-time convergent performance function is developed via exploring Bézier curve to quantitatively characterize the transient and steady-state behaviors of the pose tracking error system. The major advantage of the proposed function is that the actuator saturation phenomenon at the beginning can be effectively reduced. Then, an anti-saturated pose tracking controller is devised along with an adaptive saturation compensator. Wherein, the finite-time stability of both the pose and its velocity error signals are guaranteed simultaneously in the presence of actuator saturation. Finally, 2 groups of illustrative examples are organized and verify that the close-range proximity is effectively realized even with unknown target maneuver.