This paper reviews some main results and progress in distributed multi-agent coordination, focusing on papers published in major control systems and robotics journals since 2006. Distributed coordination of multiple vehicles, including unmanned aerial vehicles, unmanned ground vehicles, and unmanned underwater vehicles, has been a very active research subject studied extensively by the systems and control community. The recent results in this area are categorized into several directions, such as consensus, formation control, optimization, and estimation. After the review, a short discussion section is included to summarize the existing research and to propose several promising research directions along with some open problems that are deemed important for further investigations.

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An Overview of Recent Progress in the Study of Distributed Multi-Agent Coordination

This article reviews some main results and progress in distributed multi-agent coordination, focusing on papers published in major control systems and robotics journals since 2006. Distributed coordination of multiple vehicles, including unmanned aerial vehicles, unmanned ground vehicles and unmanned underwater vehicles, has been a very active research subject studied extensively by the systems and control community. The recent results in this area are categorized into several directions, such as consensus, formation control, optimization, task assignment, and estimation. After the review, a short discussion section is included to summarize the existing research and to propose several promising research directions along with some open problems that are deemed important for further investigations.

An Overview of Recent Progress in the Study of Distributed Multi-agent Coordination

Formation control analysis and design problems for unmanned aerial vehicle (UAV) swarm systems to achieve time-varying formations are investigated. To achieve predefined time-varying formations, formation protocols are presented for UAV swarm systems first, where the velocities of UAVs can be different when achieving formations. Then, consensus-based approaches are applied to deal with the time-varying formation control problems for UAV swarm systems. Necessary and sufficient conditions for UAV swarm systems to achieve time-varying formations are proposed. An explicit expression of the time-varying formation center function is derived. In addition, a procedure to design the protocol for UAV swarm systems to achieve time-varying formations is given. Finally, a quadrotor formation platform, which consists of five quadrotors is introduced. Theoretical results obtained in this brief are validated on the quardrotor formation platform, and outdoor experimental results are presented.

Time-Varying Formation Control for Unmanned Aerial Vehicles: Theories and Applications

This note investigates the finite-time attitude control problems for a single spacecraft and multiple spacecraft. First of all, a finite-time controller is designed to solve finite-time attitude tracking problem for a single spacecraft. Rigorous proof shows that the desired attitude can be tracked in finite time in the absence of disturbances. In the presence of disturbances, the tracking errors can reach a region around the origin in finite time. Then, based on the neighbor rule, a distributed finite-time attitude control law is proposed for a group of spacecraft with a leader-follower architecture. Under the finite-time control law, the attitude synchronization can be achieved in finite time.

Finite-Time Attitude Tracking Control of Spacecraft With Application to Attitude Synchronization

Time-varying formation tracking analysis and design problems for second-order Multi-Agent systems with switching interaction topologies are studied, where the states of the followers form a predefined time-varying formation while tracking the state of the leader. A formation tracking protocol is constructed based on the relative information of the neighboring agents. Necessary and sufficient conditions for Multi-Agent systems with switching interaction topologies to achieve time-varying formation tracking are proposed together with the formation tracking feasibility constraint based on the graph theory. An approach to design the formation tracking protocol is proposed by solving an algebraic Riccati equation, and the stability of the proposed approach is proved using the common Lyapunov stability theory. The obtained results are applied to solve the target enclosing problem of a multiquadrotor unmanned aerial vehicle (UAV) system consisting of one leader (target) quadrotor UAV and three follower quadrotor UAVs. A numerical simulation and an outdoor experiment are presented to demonstrate the effectiveness of the theoretical results.

Time-Varying Formation Tracking for Second-Order Multi-Agent Systems Subjected to Switching Topologies With Application to Quadrotor Formation Flying

This paper addresses the leader-follower synchronization problem of uncertain networked Euler-Lagrange systems under directed interconnection graphs in the presence of communication constraints. We present an adaptive distributed control algorithm such that a group of Euler-Lagrange systems asymptotically synchronize their states to those of a dynamic leader with a time-varying trajectory. The information exchange between all systems in the network is assumed to be discrete in time, intermittent, and subject to irregular communication delays and possible packets dropouts. It is shown that leader-follower synchronization is reached for arbitrary characteristics of the communication process provided that the directed interconnection graph contains a spanning tree. Simulation results are given to illustrate the effectiveness of the proposed control scheme.

Leader-Follower Synchronization of Euler-Lagrange Systems With Time-Varying Leader Trajectory and Constrained Discrete-Time Communication

Hybrid global exponential stabilization on SO(3)

We consider the consensus problem of high-order multi-agent systems, described by multiple integrator dynamics, under general directed graphs. In contrast to the existing results, we propose a fully-distributed consensus algorithm, albeit employing static state feedback. Specifically, it is shown that, with a suitably designed similarity transformation, consensus is reached under only the necessary and sufficient condition of an interconnection graph having a spanning tree. The proposed approach relaxes some restrictive assumptions commonly considered in the available literature, such as imposing global gains in the network and/or exploiting additional information from neighboring agents other than their position-like states. In addition, the proposed approach enables the explicit determination of the final consensus state even in the presence of constant communication delays. Simulation results are provided to illustrate the effectiveness of the proposed approach.

Distributed Consensus Algorithms for a Class of High-Order Multi-Agent Systems on Directed Graphs

This paper presents an approach for the design of globally exponentially stable hybrid attitude and gyro-bias observers on $SO(3) \times \mathbb {R}^3$ . First, we propose a hybrid observer developed in a generic manner involving a generic family of potential functions with specific properties. Thereafter, we present a design method for such potential functions via an appropriate angular warping transformation applied to a new potential function on $SO(3)$ . This results in a hybrid observer that uses directly body-frame measurements of known inertial vectors.

Abdelkader Abdessameud

Papers

Leader-Follower Synchronization of Euler-Lagrange Systems With Time-Varying Leader Trajectory and Constrained Discrete-Time Communication

Hybrid global exponential stabilization on SO(3)

Distributed Consensus Algorithms for a Class of High-Order Multi-Agent Systems on Directed Graphs

Hybrid Attitude and Gyro-Bias Observer Design on $SO(3)$

Distributed output regulation of heterogeneous linear multi-agent systems with communication constraints