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A novel guidance law that utilizes optimal control theory in combination with linear time-varying state-transition matrices to calculate the optimal path for a chaser spacecraft from its initial point to a desired final point and a desired amount of time is proposed in this paper. The optimal guidance law is formulated using more accurate second-order integral form of Gauss Variational Equations to map control accelerations to the dynamics in terms of relative orbital elements. When comparing the second-order form against the traditional Gauss Variational Equations, the guidance law results in a 15% reduction in control demand. In addition, this paper presents a new method that allows for the closed-loop testing of guidance, navigation and control systems with realistic software models of GPS receivers, RADAR systems for on-board relative navigation, and ground-station up-links of the target states. Specifically, utilizing the signal-to-noise ratio of various sensors, the errors that arise due to hardware noise and/or environmental factors can be modeled accurately based on the communication link. The guidance law is tested using the newly developed software-in-the-loop test-bed for a far-range formation flight scenario around the non-cooperative Alouette-2 spacecraft as well as on an arbitrary defined highly elliptical orbit.

This paper investigates the coordinated attitude control problem with fractional order sliding mode control theory for spacecraft formation flying by considering of unknown disturbance, inertia uncertainty, partial loss of actuators, and communication delay. Two types of fractional order sliding mode control laws are proposed to solve the considered design problem. The first one is based on the Chebyshev neural network technique, and the second one is involved with the integral‐type and super‐twisting sliding mode control methods. Compared to traditional sliding mode control methods, the developed fractional order sliding mode control strategies can achieve a faster convergence speed. Simulation results based on a group of three spacecrafts are presented to demonstrate the performance of the proposed coordinated attitude control approaches.

The problem of the relative position coordinated control for spacecraft formation flying with a leader spacecraft under the obstacle environment is the focus of this paper. To avoid obstacle/collision and maintain the formation configuration, the Null-Space-Based behavioral control architecture is built by defining the priorities of the basic tasks and computing the corresponding velocity vectors. Through the null-space projection, the desired velocity of each follower spacecraft can be calculated by merging the basic tasks. Moreover, due to the partial access to the dynamic leader spacecraft’s states, the distributed estimators are presented for each follower spacecraft. Then, based on the desired velocity, the adaptive coordinated tracking control algorithm incorporated with the barrier Lyapunov function is designed such that the states satisfy the time-varying constraints, even subject to uncertainties and unknown disturbances. Finally, numerical simulations are performed to illustrate the main results.

This paper investigates a finite-time coordinated controller for spacecraft formation flying subject to external disturbances and limited communication resources. An event-triggered strategy is adopted to reduce the communication between disturbance observer and controller, between controller and actuator, and between neighboring spacecraft, simultaneously, which is more significant for coordinated control. To compensate for the external disturbances, a hyperbolic tangent function-based adaptive finite-time disturbance observer is established without the advanced knowledge of the upper bound of the derivative of the disturbance. The designed disturbance observer and controller are integrated through event-triggered strategy. The stabilities of the closed-loop system can be verified by the Lyapunov theorem without applying the separation principle. Simulation studies are provided to prove the effectiveness of the proposed control scheme.

This paper investigates the relative position coordinated control problem for a group of formation flying spacecraft under a directed communication network and resource constraints. An event-based coordinated control scheme without resorting to neighbors’ velocity information is proposed to achieve the formation-keeping maneuvers. Considering expensive communication cost in spacecraft formation, a novel event-triggered mechanism is developed, where the information transmission among spacecraft is established only when the defined triggering threshold is exceeded; moreover, each spacecraft only needs to compute its own control command at triggering time instants, thus ameliorating the issue of computation limitation inherent in the space-qualified microprocessor. Apart from the above, an explicit positive lower bound on the inter-event time internals is rigorously guaranteed such that no Zeno behavior exhibits. By resorting to the input-to-state practical stability and Lyapunov theory, a sufficient criterion on parameters selection is derived to ensure that the overall closed-loop system is uniformly ultimately bounded stable. Finally, numerical simulations are carried out to demonstrate the effectiveness of the theoretical results.

In this paper the problems of multi-agent spacecraft attitude formation and tracking control on T S O ( 3 ) N are addressed using rotation matrices and globally continuous control protocols derived using Morse-Bott-Lyapunov functions, including a feedback reshaping strategy for enlarging the region of attraction of the desired equilibrium manifold. For attitude formation control the spacecraft comes to rest with desired relative attitudes between connected pairs according to the specified communication topology. Examples include N spacecraft with undirected ring or complete graph topologies achieving a desired balanced configuration on the circle or on SO (3). The proposed attitude formation tracking control protocol, which extends a proposed tracking controller for a single spacecraft on TSO (3), consists of one or more leaders tracking a time-varying command while the followers either achieve attitude synchronization or a desired time-varying attitude formation with the leaders.

The problem of controlling the relative position and velocity in multi-spacecraft formation flying in the planetary orbits is an enabling technology for current and future research. This paper proposes a family of tracking controllers for different dynamics of Spacecraft Formation Flying (SFF) in the framework of port-Hamiltonian (pH) systems through application of timed Interconnection and Damping Assignment Passivity-Based Control (IDA-PBC). The leader–multi-follower architecture is used to address this problem. In this regard, first we model the spacecraft motion in the pH framework in the Earth Centered Inertial frame and then transform it to the Hill frame which is a special local coordinate system. By this technique, we may present a unified structure which encompasses linear/nonlinear dynamics, with/without perturbation. Then, using the timed IDA-PBC method and the contraction analysis, a new method for controlling a family of SFF dynamics is developed. The numerical simulations show the efficiency of the approach in two different cases of missions.

This paper mainly studies the distributed fixed-time coordinated attitude tracking control problem of spacecraft formation with a dynamic leader spacecraft under directed communication topology. Follower spacecraft cannot communicate directly with the leader spacecraft; therefore, in order to enable them to obtain the target attitude information, a fixed-time state estimator that can be applied to directed graphs is designed. Based on the estimators, a distributed fixed-time attitude tracking control law is proposed. The settling time of the fixed-time algorithm is only related to the parameters of the control law and independent of the initial state; thus, the proposed control law can reduce the influence of the dynamic leader attitude on the spacecraft formation-coordinated attitude tracking control system. Moreover, external disturbances and spacecraft inertia uncertainty were also considered in the design of the control law. The stability of the system was verified by Lyapunov stability theory, and the effectiveness of the control law was verified by numerical simulation.

This paper studies the attitude synchronization control problem for a group of spacecraft. Considering inertia uncertainties and external disturbances with unknown bounds, a decentralized adaptive control scheme is developed using nonsingular fast terminal sliding mode (NFTSM). A multispacecraft NFTSM is firstly designed, which contains the advantages of the nonsingular terminal sliding mode and the traditional linear sliding mode together. Then, the continuous decentralized adaptive NFTSM control laws with boundary layer by employing NFTSM associated with novel adaptive architecture are proposed, which can eliminate the chattering, and guarantee the attitude tracking errors converge to the regions containing the origin in finite time. At last, numerical simulations are presented to demonstrate the performance of the proposed control strategy.

This study explores the challenge of tracking control for spacecraft formation flying (SFF) in the presence of dynamic uncertainties and external perturbations. Firstly, sliding mode control combined with backstepping control is used to address saturation issues. Then, neural networks, minimal parameter learning, and adaptive control are integrated to handle dynamic uncertainties and actuator failures. To alleviate the communication load, an event‐triggered mechanism is ultimately implemented, which leads to the development of an adaptive sliding mode fault‐tolerant control algorithm based on an event‐triggered neural network. This control architecture achieves significant advancements over traditional techniques: (1) ensuring system robustness and adaptability in complex scenarios with uncertain system dynamics and external disturbances, effectively counteracting actuator failures and input saturation issues; (2) significantly reducing transmission and computational burdens in resource‐limited networked systems through the adoption of event‐triggered control (ETC) mechanisms; (3) achieving high‐precision tracking performance for SFF without relying on prior knowledge of the system’s inherent dynamics, environmental disturbances, or potential actuator deficiencies. The Lyapunov approach is utilized to confirm the closed‐loop system’s boundedness. Finally, the proposed method’s efficacy is confirmed via simulations with a two‐satellite formation.