Explore the vast range of titles available.

This study studies the problem of synchronisation control for spacecraft formation via extended state observer approach over directed communication topology. The attitude kinematics and dynamics of spacecraft are described by Lagrangian formulations, and the decentralised controller is designed with time-varying external disturbances and unmeasurable velocity information. In particular, the estimation of disturbances obtained via extended state observer is used for the decentralised controller design. A novel Lyapunov function is proposed to show that both static regulation and dynamic synchronisation are realised. Finally, simulation results are given to demonstrate the effectiveness of the controllers proposed in this study.

This paper investigates the problem of attitude synchronization tracking of multiple spacecraft in the presence of limited inter-spacecraft communication, model uncertainties and external disturbances. A distributed adaptive event-triggered control scheme for attitude synchronization tracking of multiple spacecraft is proposed. In the proposed control scheme, the controllers are updated in an aperiodic manner at the event-sampled instants when a defined event-triggered error exceeds a state-dependent threshold. The inter-spacecraft communication topology in the control scheme is assumed to be undirected. The stability of the resulting closed-loop systems can be guaranteed by application of the Lyapunov function, and no accumulation of triggering instants is also ensured. Finally, simulation results are given to illustrate the effectiveness of the proposed control scheme.

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.

Purpose This paper aims to investigate the attitude synchronization issue of multi-spacecraft formation flying systems under the limited communication resources. Design/methodology/approach The authors propose a distributed learning Chebyshev neural network controller (LCNNC) combining a dynamic event-triggered (DET) mechanism and a learning CNN model to achieve accurate multi-spacecraft attitude synchronization under communication constraints. Findings The proposed method can significantly reduce the internal communication frequency and improve the attitude synchronization accuracy. Practical implications This method requires the low communication resources, has a high control accuracy and is thus suitable for engineering applications. Originality/value A novel DET mechanism-based LCNNC is proposed to achieve the accurate multi-spacecraft attitude synchronization under communication constraints.

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.

This work investigates the attitude stabilization and synchronization problem for multi-combined spacecraft with time-varying inertia parameters, external disturbances, and input constraints. First, the comprehensive disturbance is reconstructed considering the influence of inertia uncertainties for controller system design. And then, a novel disturbance observer is developed, and a state feedback controller developed through comprehensive disturbance estimation is proposed. The characteristic of uniform ultimate boundedness for the closed-loop attitude system is proved according to Lyapunov stability analysis, producing the sufficient linear matrix inequality (LMI) condition for the disturbance observer and state feedback controller designs. It is worth noting that the observer and controller gain matrices are solved simultaneously. The feasibility of the attitude stabilization control strategy is demonstrated through numerical simulations.

This paper investigates the distributed fixed-time attitude synchronization control problem for multiple rigid spacecraft system with external disturbances. Based on sliding-mode estimators, the authors remove the requirement of neighbours’ input control information. Using the fixed-time-based terminal sliding mode, the distributed adaptive control laws are developed to guarantee the attitude tracking errors converge to the regions in fixed time independent of initial conditions, and adaptive laws are employed to deal with external disturbances. Finally, numerical simulations are presented to illustrate the performance of the proposed controllers.

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.

Most of the recent research on distributed formation control of unmanned aerial vehicle (UAV) swarms is founded on position, distance, and displacement-based approaches; however, a very promising approach, i.e., bearing-based formation control, is still in its infancy and needs extensive research effort. In formation control problems of UAVs, Euler angles are mostly used for orientation calculation, but Euler angles are susceptible to singularities, limiting their use in practical applications. This paper proposed an effective method for time-varying velocity and orientation leader agents for distributed bearing-based formation control of quadcopter UAVs in three-dimensional space. It combines bearing-based formation control and quaternion-based attitude control using undirected graph topology between agents without the knowledge of global position and orientation. The performance validation of the control scheme was done with numerical simulations, which depicted that UAV formation achieved the desired geometric pattern, translation, scaling, and rotation in 3D space dynamically.

This research addresses an event-triggered fault-tolerant impulsive sliding mode control scheme that ensures fixed-time attitude synchronization between two non-identical satellites. The designed controller works based on an event-triggered linear feedback law which acts as a single estimator for the unknown dynamics as well as two types of actuator fault. Firstly, the sliding surface functions with delayed impulse are defined in a way that the system’s response becomes rapid in the presence of both small and large errors. Secondly, the proposed optimal weight constant minimizes the approximation error and provides an optimized approximation process. Furthermore, utilizing the generalized error dynamics and the proposed reaching law, the system’s stability is shown by Lyapunov analysis. Finally, the controller’s efficiency is confirmed by conducting two numerical simulation results.