11,337 research outputs found
Consensus for switched networks with unknown but bounded disturbances
We consider stationary consensus protocols for networks of dynamic agents
with switching topologies. The measure of the neighbors' state is affected by
Unknown But Bounded disturbances. Here the main contribution is the formulation
and solution of what we call the -consensus problem, where the states
are required to converge in a tube of ray asymptotically or in
finite time.Comment: 18 pages, 3 figures. The manuscript has been submitted for the
Special issue on Control and optimization in Cooperative Networks. Submitted
to SIAM SICO
Finite-Time Resilient Formation Control with Bounded Inputs
In this paper we consider the problem of a multi-agent system achieving a
formation in the presence of misbehaving or adversarial agents. We introduce a
novel continuous time resilient controller to guarantee that normally behaving
agents can converge to a formation with respect to a set of leaders. The
controller employs a norm-based filtering mechanism, and unlike most prior
algorithms, also incorporates input bounds. In addition, the controller is
shown to guarantee convergence in finite time. A sufficient condition for the
controller to guarantee convergence is shown to be a graph theoretical
structure which we denote as Resilient Directed Acyclic Graph (RDAG). Further,
we employ our filtering mechanism on a discrete time system which is shown to
have exponential convergence. Our results are demonstrated through simulations
Robust Distance-Based Formation Control of Multiple Rigid Bodies with Orientation Alignment
This paper addresses the problem of distance- and orientation-based formation
control of a class of second-order nonlinear multi-agent systems in 3D space,
under static and undirected communication topologies. More specifically, we
design a decentralized model-free control protocol in the sense that each agent
uses only local information from its neighbors to calculate its own control
signal, without incorporating any knowledge of the model nonlinearities and
exogenous disturbances. Moreover, the transient and steady state response is
solely determined by certain designer-specified performance functions and is
fully decoupled by the agents' dynamic model, the control gain selection, the
underlying graph topology as well as the initial conditions. Additionally, by
introducing certain inter-agent distance constraints, we guarantee collision
avoidance and connectivity maintenance between neighboring agents. Finally,
simulation results verify the performance of the proposed controllers.Comment: IFAC Word Congress 201
Consensus-based control for a network of diffusion PDEs with boundary local interaction
In this paper the problem of driving the state of a network of identical
agents, modeled by boundary-controlled heat equations, towards a common
steady-state profile is addressed. Decentralized consensus protocols are
proposed to address two distinct problems. The first problem is that of
steering the states of all agents towards the same constant steady-state
profile which corresponds to the spatial average of the agents initial
condition. A linear local interaction rule addressing this requirement is
given. The second problem deals with the case where the controlled boundaries
of the agents dynamics are corrupted by additive persistent disturbances. To
achieve synchronization between agents, while completely rejecting the effect
of the boundary disturbances, a nonlinear sliding-mode based consensus protocol
is proposed. Performance of the proposed local interaction rules are analyzed
by applying a Lyapunov-based approach. Simulation results are presented to
support the effectiveness of the proposed algorithms
Opinion Dynamics in Social Networks with Hostile Camps: Consensus vs. Polarization
Most of the distributed protocols for multi-agent consensus assume that the
agents are mutually cooperative and "trustful," and so the couplings among the
agents bring the values of their states closer. Opinion dynamics in social
groups, however, require beyond these conventional models due to ubiquitous
competition and distrust between some pairs of agents, which are usually
characterized by repulsive couplings and may lead to clustering of the
opinions. A simple yet insightful model of opinion dynamics with both
attractive and repulsive couplings was proposed recently by C. Altafini, who
examined first-order consensus algorithms over static signed graphs. This
protocol establishes modulus consensus, where the opinions become the same in
modulus but may differ in signs. In this paper, we extend the modulus consensus
model to the case where the network topology is an arbitrary time-varying
signed graph and prove reaching modulus consensus under mild sufficient
conditions of uniform connectivity of the graph. For cut-balanced graphs, not
only sufficient, but also necessary conditions for modulus consensus are given.Comment: scheduled for publication in IEEE Transactions on Automatic Control,
2016, vol. 61, no. 7 (accepted in August 2015
Prescribed Performance Control for Signal Temporal Logic Specifications
Motivated by the recent interest in formal methods-based control for dynamic
robots, we discuss the applicability of prescribed performance control to
nonlinear systems subject to signal temporal logic specifications. Prescribed
performance control imposes a desired transient behavior on the system
trajectories that is leveraged to satisfy atomic signal temporal logic
specifications. A hybrid control strategy is then used to satisfy a finite set
of these atomic specifications. Simulations of a multi-agent system, using
consensus dynamics, show that a wide range of specifications, i.e., formation,
sequencing, and dispersion, can be robustly satisfied.Comment: 9 pages - this an extended version of the 56th IEEE Conference on
Decision and Control (2017) versio
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