Attitude Synchronization Of Multiple Spacecraft Research Articles

Chattering Free Distributed Event-triggered Adaptive Attitude Synchronization of Multiple Spacecraft with Positive Minimum Inter-event Times

Chattering Free Distributed Event-triggered Adaptive Attitude Synchronization of Multiple Spacecraft with Positive Minimum Inter-event Times

Finite-Time Distributed Attitude Synchronization for Multiple Spacecraft With Angular Velocity and Input Constraints

The attitude synchronization problem for multiple spacecraft with angular velocity and input constraints is investigated in this article, under the mild assumptions that the leader’s states can reach each follower through a path and the communications between followers are bidirectional. An adaptive finite-time distributed observer is designed to estimate the leader’s states for each follower spacecraft, which has the superiority in the fully distributed that the communication topology or some other global information is not required, and the finite-time convergence can be guaranteed. Furthermore, the novel auxiliary systems are first proposed to avoid the angular velocity and input constraints being violated, while the finite-time command filtered backstepping controller is designed to track the leader’s attitude motion. The remarkable features of the developed algorithm are the global finite-time attitude consensus of multiple spacecraft, with the constraints satisfied. Moreover, the efficiency of the proposed method is illustrated by numerical simulations and real-time platform verification.

Distributed Adaptive Attitude Synchronization of Multiple Spacecraft With Event-Triggered Communication

This article investigates the distributed adaptive attitude synchronization problem for multiple rigid spacecraft with unknown inertial matrices and event-triggered communication. Under a directed topology condition, two distributed event-based adaptive attitude synchronization schemes are proposed. By introducing a reference system for each spacecraft, a distributed adaptive control algorithm is first developed, based on which a group of rigid spacecraft can be synchronized at a common attitude with zero angular velocity. Then, the case without angular velocity measurements is considered. By redesigning the reference system and resorting to a pseudovelocity filter, an event-based adaptive output feedback attitude synchronization algorithm is presented. It is shown that with the proposed control schemes, all the closed-loop signals are uniformly bounded and the attitude synchronization can be achieved, while Zeno behavior in each spacecraft can be excluded. Simulation results are provided to illustrate the effectiveness of the proposed control schemes.

Decentralized adaptive control for attitude synchronization of multiple spacecraft via quantized information exchange

This paper investigates the problem of decentralized attitude synchronization and tracking for a group of spacecraft, whose communication topology is undirected, subject to inter-spacecraft communication resources constraints, model uncertainties and external disturbances. In order to reduce inter-spacecraft communication burden, a quantization mechanism is developed. In the quantization mechanism, the quantized sequences, whose storage size are much smaller than that of spacecraft's attitude information, are required to be transmitted among spacecraft only when the quantized sequences changes compared with the previous one. Thus, the size of inter-spacecraft communication data can be greatly reduced. A decentralized adaptive attitude synchronization and tracking control scheme is proposed to align spacecraft's attitude and track the desired attitude. By resorting to Barbalat's Lemma, the resulting closed-loop system is proved to be uniformly ultimately bounded stable. Finally, numerical simulation results are presented to demonstrate the effectiveness of the theoretical results.

Distributed adaptive event-triggered control for attitude synchronization of multiple spacecraft

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.

Finite-time output feedback attitude synchronization for multiple spacecraft

Distributed attitude control for spacecraft formation without angular velocity measurement is complicated and challenging. Based on nonsingular terminal sliding mode, this paper designs two kinds of finite-time attitude synchronization controllers with inertia uncertainties and external disturbances. Aiming at calculating angular velocity in finite time, a nonlinear state observer and an angular velocity calculation algorithm are firstly developed. Then, two strategies for estimating reference signals and two distributed output feedback controllers, based on continuous adaptive technology and adaptive disturbance observer, are designed respectively. Different from existing results, the controllers are inherently continuous and the control chattering is greatly reduced. Also, the designed nonlinear observers need no prior knowledge on the upper bound of uncertain state and are proved finite-time convergent via Lyapunov theory. Finally, simulations and comparisons demonstrate the effectiveness of the proposed schemes.

Distributed fault‐tolerant control design for spacecraft finite‐time attitude synchronization

SummaryThis paper develops two distributed finite‐time fault‐tolerant control algorithms for attitude synchronization of multiple spacecraft with a dynamic virtual leader in the presence of modeling uncertainties, external disturbances, and actuator faults. The leader gives commands only to a subset of the followers, and the communication flow between followers is directed. By employing a novel distributed nonsingular fast terminal sliding mode and adaptive mechanism, a distributed finite‐time fault‐tolerant control law is proposed to guarantee all the follower spacecraft that finite‐time track a dynamic virtual leader. Then utilizing three distributed finite‐time sliding mode estimators, an estimator‐based distributed finite‐time fault‐tolerant control law is proposed using only the followers' estimates of the virtual leader. Both of them do not require online identification of the actuator faults and provide robustness, finite‐time convergence, fault‐tolerant, disturbance rejection, and high control precision. Finally, numerical simulations are presented to evaluate the theoretical results. Copyright © 2015 John Wiley & Sons, Ltd.

Distributed cooperative control design for finite‐time attitude synchronisation of rigid spacecraft

Two finite-time control algorithms are developed for distributed cooperative attitude synchronization of multiple spacecraft with a dynamic virtual leader. Each spacecraft is modeled as a rigid body incorporating with model uncertainty and unknown external disturbance. The virtual leader gives commands to some of the follower spacecraft, and the communication network between followers can be an undirected or a directed graph. By using two neighborhood synchronization error signals, a finite-time control algorithm is designed associated with adaptive mechanism such that all follower spacecraft synchronize to the virtual leader in finite time. Then, a novel estimator-based finite-time distributed cooperative control algorithm is developed by using the followers estimates of the virtual leader, and the convergence of the attitude and angular velocity errors can be guaranteed in finite time. Moreover, both of the control strategies are chattering-free for their continuous design. Simulation examples are illustrated to demonstrate the validity of the two algorithms.

Attitude synchronization of multiple spacecraft with cone avoidance constraints

In this paper, we consider a team of spacecraft which requires changing its orientation to a common attitude using a decentralized control scheme under a connected communication topology, while satisfying cone avoidance constraints due to blind celestial objects, plume impingement and so on. For this purpose, we first combine consensus theory and optimization theory to develop a quaternion-based attitude consensus protocol. Based on the communication graph at each time step, each spacecraft generates a guidance command or reference attitude trajectory by synthesizing a series of Laplacian-like matrix P(t), using semidefinite programming (SDP) which involves linear matrix inequalities (LMIs). It is analytically shown that this series of matrices P(t) is capable of collectively driving the initial attitudes to a common consensus attitude. For satisfying cone avoidance constraints, exclusion zones are then identified and expressed as LMIs. This identification of the exclusion zones gives rise to selecting safe waypoints from the reference attitude trajectory and then to passing through the selected waypoints while avoiding the exclusion zones via proper control inputs. This solution procedure is demonstrated via numerical simulations of coordinated attitude rendezvous and attitude formation acquisition of multiple spacecraft with cone avoidance manoeuvres.

Attitude synchronization for multiple spacecraft with input constraints

The attitude synchronization problem for multiple spacecraft with input constraints is investigated in this paper. Two distributed control laws are presented and analyzed. First, by introducing bounded function, a distributed asymptotically stable control law is proposed. Such a control scheme can guarantee attitude synchronization and the control inputs of each spacecraft can be a priori bounded regardless of the number of its neighbors. Then, based on graph theory, homogeneous method, and Lyapunov stability theory, a distributed finite-time control law is designed. Rigorous proof shows that attitude synchronization of multiple spacecraft can be achieved in finite time, and the control scheme satisfies input saturation requirement. Finally, numerical simulations are presented to demonstrate the effectiveness and feasibility of the proposed schemes.

Distributed adaptive attitude synchronization of multiple spacecraft

This paper addresses the distributed attitude synchronization problem of multiple spacecraft with unknown inertia matrices. Two distributed adaptive controllers are proposed for the cases with and without a virtual leader to which a time-varying reference attitude is assigned. The first controller achieves attitude synchronization for a group of spacecraft with a leaderless communication topology having a directed spanning tree. The second controller guarantees that all spacecraft track the reference attitude if the virtual leader has a directed path to all other spacecraft. Simulation examples are presented to illustrate the effectiveness of the results.