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This article studies the multiagent control problem for affine, rigid, and translational formation, with the aim of developing a unified distributed control strategy for global and finite-time convergence. Global stabilization of rigid formation in arbitrary dimensional spaces still remains open and challenging. This article provides a general solution to this open problem based on the sliding mode control idea. The control law design consists of two parts: the main control force regulates the trajectories of all agents to reach a sliding surface defined by an affine formation space in finite time and remain in it thereafter; the extra control force governs certain chosen leader agents towards the desired formation in the sliding surface. The article then presents in detail two approaches for designing the extra control force, one based on distance constraints and the other based on relative position constraints. For the first time, the proposed sliding mode formation control laws solve the open problem of (almost) global and finite-time stabilization of affine, rigid, and translational formations in any dimensional space. Simulation results are provided to illustrate the effectiveness of the proposed control schemes. [ABSTRACT FROM AUTHOR]

This paper discusses the distributed fixed-time containment control for networked nonlinear systems via the event/self-triggered approaches over directed graphs. A distributed event-triggered control protocol without continuous control updates is first proposed. In order to relieve the chattering effect, a modified distributed event-triggered control law is developed. To further overcome the drawback of continuous state monitoring and reduce the communication frequency between neighboring agents, a distributed chattering-free self-triggered control strategy is accordingly designed. A favorable aspect of our work is that the unnecessary resource utilizations of computation, communication as well as control updates can be saved while sustaining the desired control properties and excluding the Zeno behavior. Another distinct feature of this paper lies in that the containment control objective is realized in fixed time and the estimate of settling time can be prescribed without dependence on initial states of networked agents. Finally, some simulation results are provided to illustrate the effectiveness of the theoretical control schemes. [ABSTRACT FROM AUTHOR]

In this paper, we propose a distance-based formation control strategy for a group of mobile agents to achieve almost global convergence to a target formation shape provided that the formation is represented by a complete graph, and each agent is governed by a single-integrator model. The fundamental idea of achieving almost global convergence is to use a virtual formation of which the dimension is augmented with some virtual coordinates. We define a cost function associated with the virtual formation and apply the gradient-descent algorithm to the cost function so that the function has a global minimum at the target formation shape. We show that all agents finally achieve the target formation shape for almost all initial conditions under the proposed control law. [ABSTRACT FROM AUTHOR]

This paper proposes a general approach to design convergent coordination control laws for multiagent systems subject to motion constraints. The main contribution of this paper is to prove in a constructive way that a gradient-descent coordination control law designed for single integrators can be easily modified to adapt for various motion constraints such as nonholonomic dynamics, linear/angular velocity saturation, and other path constraints while preserving the convergence of the entire multiagent system. The proposed approach is applicable to a wide range of coordination tasks such as rendezvous and formation control in two and three dimensions. As a special application, the proposed approach solves the problem of distance-based formation control subject to nonholonomic and velocity saturation constraints. [ABSTRACT FROM AUTHOR]

Use of a gradient descent control law has been a popular method to effectively stabilize undirected rigid formations, by assuming that interagent distances between a certain set of neighboring agent pairs can be accurately specified and measured. This paper examines the collective motion behavior for an infinitesimally rigid formation in a three-dimensional ambient space, in the case that neighboring agent pairs have slightly differing views or measurements of the desired interagent distances they are tasked to maintain. It is shown that the formation shape will converge exponentially fast to a rigid one, while additional rigid helical motions of the final formation will occur. We further discuss the convergence to the equilibrium motions, and derive certain motion parameter formulas to describe the rigid formation movements by employing the angular momentum concept from classical mechanics. Finally, we explain how the idea can be used for steering a rigid formation to move as a rigid body. [ABSTRACT FROM AUTHOR]