Human-Oriented Opportunistic Control for Time-Varying Formation of NASVs With Opportunistic-Moving Leader and Intermittent Human–Computer Interactions

Distributed time-varying output formation (TVOF) control problems are addressed in this paper using an adaptive output-feedback approach for general linear swarm systems with directed interaction topology. Compared with the previous work on formation control, a desired TVOF can be achieved by the swarm system without using any global information about the interaction topology. Firstly, an adaptive formation controller is constructed via dynamic output feedback information and sequential observers. Then,a distributed algorithm is proposed to determine the parameters in the adaptive formation controller. A feasible TVOF set is given. Moreover, the stability of the proposed distributed algorithm is proved. Finally, a simulation example is presented to demonstrate the effectiveness of the obtained results.

This paper tackles the robust leaderless Time-Varying Formation (TVF) control problem for the Unmanned Aerial Vehicle (UAV) swarm system with Lipschitz nonlinear dynamics, external disturbances and directed switching topologies. In comparison with the previous achievements on formation control problems, the UAV swarm system with Lipschitz nonlinear dynamics can accomplish the pre-designed TVF while tracking a pre-given trajectory which is produced by a virtual leader UAV in the presence of external disturbances. Firstly, by applying the consensus theory, a TVF controller is developed with the local neighborhood status information, the errors of real time status of all UAVs, the expected formation configuration and the pre-given trajectory under directed switching topologies. Secondly, through a certain matrix variable substitution, the UAV swarm system formation control issue is transformed into a lower dimensional asymptotically stable control issue. Thirdly, by introducing the minimum dwell time, the design steps of formation control algorithm are further acquired. In the meantime, the stability of the UAV swarm system is analyzed through the construction of a piecewise continuous Lyapunov functional and via the Linear Matrix Inequalities (LMIs) method. Finally, the comparison results of a numerical simulation are elaborated to verify the validity of the proposed approach.

Optimal distributed time-varying formation control for second-order multiagent systems: LQR-based method

Fully distributed time-varying formation (TVF) control problems are addressed in this paper using an adaptive output-feedback approach for general linear swarm systems with fixed and switching topologies. In contrast to the earlier results on formation control problems, the general linear swarm system can achieve the predefined TVF using only local output information and independent of the Laplacian matrix associated with the communication topologies. The implementation cost of calculating the global information and requiring full state information is avoided when achieving the desired TVF. First, a node-based TVF control protocol is constructed via dynamic output feedback for the case with fixed communication topology, where adaptive-based coupling weights are introduced to eliminate the dependence on the global information about the topology. Then an algorithm is presented to determine the gain matrices in the node-based adaptive TVF control protocol, and a feasible formation constraint is provided. The stability of the algorithm is proved based on the Lyapunov theory. Furthermore, under the case of switching communication topologies, an edge-based TVF control protocol is constructed with dynamic output feedback and an adaptive law for adjusting the coupling weights among agents. A sufficient condition is derived using the common Lyapunov theory for general linear swarm systems to achieve the predefined TVF satisfying the feasible formation constraint. Two numerical examples are presented to illustrate the theoretical results.

This article investigates the tracking-oriented robust leaderless time-varying formation (TVF) control problem for unmanned aerial vehicle swarm systems (UAVSSs) with Lipschitz nonlinear dynamics under directed topology, where external disturbances are random and bounded, and communication delays (CDs) are bounded. In this article, a state-feedback control approach is adopted to make sure that a UAVSS forms a desired TVF and follows a specified trajectory when CDs and external disturbances occur. First, a novel PD-like formation control protocol with several unknown parameters and CDs is designed. The protocol contains the information of the local neighborhood status and its differential quantities. Second, the tracking-oriented robust leaderless TVF control problem with Lipschitz dynamics, external disturbances, and CDs is transformed into a problem about asymptotic stability of a lower dimensional closed-loop control system through a special matrix decomposition. Third, a theorem is proposed to determine the unknown parameters of the control protocol and the upper bound of CDs. In the theorem, sufficient conditions for a UAVSS to attain the anticipated TVF and trajectory tracking are obtained. A Lyapunov-Krasovskii (LK) functional is constructed to verify that the error among the practical flight state of UAVs, the anticipant TVF configuration, and tracking trajectory can asymptotically converge to 0. Finally, with the presentation of a simulation case, the effectiveness of the theoretical results is illustrated.

In this paper, distributed time-varying formation (TVF) control problems for general linear swarm systems with switching interaction topologies are investigated using an adaptive dynamic protocol. First, a TVF control protocol for switching interaction topologies is constructed using the states of neighboring agents. In the protocol, an adaptive controller that employs gain scheduling technique is provided to estimate the coupling weights among agents. Compared with the previous studies on formation control, the desired formation can be specified by piecewise continuously time-varying differentiable vectors, the interaction topology can be switching, and the disadvantage of requiring global information of the interaction topologies is removed in this paper. Then, an algorithm including a feasible formation condition is proposed to determine the gain matrices of the distributed adaptive formation protocol by solving a linear matrix inequality for swarm systems with switching interaction topologies. Moreover, under the designed distributed adaptive formation protocol, sufficient condition for general linear swarm systems with switching interaction topologies to achieve the given TVF is derived using the Lyapunov theory. Finally, numerical simulations are presented to demonstrate the obtained results.

Distributed adaptive time-varying formation for multi-agent systems with general high-order linear time-invariant dynamics

Currently, autonomous underwater vehicles (AUVs) are facing various challenges, rendering multiple-AUV (multi-AUV) formation control a pivotal research direction. The issues surrounding formation control for a multi-AUV system to establish time-varying formations must be investigated. This paper discusses the formation protocol of multi-AUV systems in order to establish the defined time-varying formations. First, when these systems establish formations, the speed of each AUV can be equivalent. After that, consensus-based methods are used to solve the time-varying formation-control problem. The necessary and sufficient process of multi-AUV in achieving time-varying formations is proved. Furthermore, the formula for the time-varying formation center function is provided. Further, we present a protocol law for multi-AUVs to establish time-varying formations. Finally, the theoretical results of a simulation are presented, which validate the formation protocol.

In this paper, distributed time-varying formation control problems for general high-order linear time invariant (LTI) multiagent systems are studied using an adaptive based approach. Firstly, constructed by the states of neighboring agents, a time-varying formation control protocol is proposed, where the adaptive gain scheduling technique is employed to adjusting the coupling weights between neighboring agents. Secondly, an algorithm with two steps is presented to design the distributed adaptive formation control protocol, where a description of the feasible time-varying formation set is given. In contrast to the existing results on formation control, no global information about the interaction topologies is required. Then, the stability of the algorithm is proved using the Lyapunov theory. If the predefined time-varying formation belongs to the feasible formation set, time-varying formation is shown to be achieved by general high-order LTI multi-agent systems using the distributed adaptive formation protocol designed in the proposed algorithm. Finally, a numerical example is given to demonstrate the effectiveness of the theoretical results.

Robust time-varying formation control for underactuated autonomous underwater vehicles with disturbances under input saturation

ABSTRACTTime-varying formation analysis and design problems for double-integrator multi-agent systems with jointly connected topologies are investigated. Different from the previous work on formation control, in this paper, the formation is specified by time-varying piecewise continuously differentiable vectors and the topology can be disconnected at any time instant. First, a distributed formation control protocol is constructed using local neighbour-to-neighbour information. In the case where the switching topology is jointly connected, necessary and sufficient conditions for double-integrator multi-agent systems to achieve time-varying formations are proposed, where the formation feasibility constraint is also derived. To describe the macroscopic movement of the whole formation, explicit expressions of the formation reference are presented, the motion modes of which can be partially assigned. Moreover, an approach to design the formation control protocol is given, which is fully distributed and requires no global information about the topology. Finally, the obtained theoretical results are applied to deal with the time-varying formation control problems of multi-vehicle systems.

Distributed time-varying formation control problems are considered for general high-order linear time-invariant multi-agent systems using an adaptive based approach with undirected interaction topology. Based on relative neighboring state information, by distributing each node a time-varying coupling weight, a distributed adaptive control protocol is proposed for achieving time-varying formation. A set of the feasible time-varying formation constraint is given. It is revealed that the formation can be specified by piecewise continuously differentiable vectors, under the distributed adaptive formation control protocol, and no global information about the interaction topology is required. Then an algorithm is presented to determine the distributed adaptive formation control protocol. On the basis of the Lyapunov theory, the stability of the algorithm is investigated. A numerical simulation example is finally given to verify the theoretical results.

This paper mainly addresses the formation control problem for a group of tail-sitters in transition flight between forward and vertical flight. A robust formation control method is proposed to achieve the aggressive time-varying formation subject to nonlinear dynamics and uncertainties. For each tail-sitter, the proposed control method results in a composite controller that includes a trajectory tracking controller and an attitude controller to achieve the translational and rotational motion control, respectively. It is proven that tracking errors of the proposed global closed-loop system can converge to a given neighborhood around the origin in a finite time. Finally, the simulation studies for multiple tail-sitters to accomplish the time-varying formation in transition flight are presented to show the effectiveness of the proposed control strategy.

Event-triggered time-varying formation control for general linear multi-agent systems

Time-varying formation analysis problems for double-integrator multi-agent systems with jointly connected topologies are investigated. Different from the previous work on formation control, in this paper, the formation is specified by time-varying piecewise continuously differentiable vectors and the topology can be disconnected at any time instant. Firstly, a distributed formation control protocol is constructed using local neighbor-to-neighbor information. In the case where the switching topology is jointly connected, necessary and sufficient conditions for double-integrator multi-agent systems to achieve time-varying formations are proposed, where the formation feasibility constraint is also derived. To describe the macroscopic movement of the whole formation, explicit expressions of the formation reference are presented, the motion modes of which can be partially assigned. Finally, the obtained theoretical results are applied to deal with the time-varying formation control problems of multi-vehicle systems.