2,504 research outputs found
Bio-inspired vision-based leader-follower formation flying in the presence of delays
Flocking starlings at dusk are known for the mesmerizing and intricate shapes they generate, as well as how fluid these shapes change. They seem to do this effortlessly. Real-life vision-based flocking has not been achieved in micro-UAVs (micro Unmanned Aerial Vehicles) to date. Towards this goal, we make three contributions in this paper: (i) we used a computational approach to develop a bio-inspired architecture for vision-based Leader-Follower formation flying on two micro-UAVs. We believe that the minimal computational cost of the resulting algorithm makes it suitable for object detection and tracking during high-speed flocking; (ii) we show that provided delays in the control loop of a micro-UAV are below a critical value, Kalman filter-based estimation algorithms are not required to achieve Leader-Follower formation flying; (iii) unlike previous approaches, we do not use external observers, such as GPS signals or synchronized communication with flock members. These three contributions could be useful in achieving vision-based flocking in GPS-denied environments on computationally-limited agents
Bearing-Based Distributed Control and Estimation of Multi-Agent Systems
This paper studies the distributed control and estimation of multi-agent
systems based on bearing information. In particular, we consider two problems:
(i) the distributed control of bearing-constrained formations using relative
position measurements and (ii) the distributed localization of sensor networks
using bearing measurements. Both of the two problems are considered in
arbitrary dimensional spaces. The analyses of the two problems rely on the
recently developed bearing rigidity theory. We show that the two problems have
the same mathematical formulation and can be solved by identical protocols. The
proposed controller and estimator can globally solve the two problems without
ambiguity. The results are supported with illustrative simulations.Comment: 6 pages, to appear in the 2015 European Control Conferenc
Dynamic Quantized Consensus of General Linear Multi-agent Systems under Denial-of-Service Attacks
In this paper, we study multi-agent consensus problems under
Denial-of-Service (DoS) attacks with data rate constraints. We first consider
the leaderless consensus problem and after that we briefly present the analysis
of leader-follower consensus. The dynamics of the agents take general forms
modeled as homogeneous linear time-invariant systems. In our analysis, we
derive lower bounds on the data rate for the multi-agent systems to achieve
leaderless and leader-follower consensus in the presence of DoS attacks, under
which the issue of overflow of quantizer is prevented. The main contribution of
the paper is the characterization of the trade-off between the tolerable DoS
attack levels for leaderless and leader-follower consensus and the required
data rates for the quantizers during the communication attempts among the
agents. To mitigate the influence of DoS attacks, we employ dynamic
quantization with zooming-in and zooming-out capabilities for avoiding
quantizer saturation
Efficient, Optimal -Leader Selection for Coherent, One-Dimensional Formations
We study the problem of optimal leader selection in consensus networks with
noisy relative information. The objective is to identify the set of leaders
that minimizes the formation's deviation from the desired trajectory
established by the leaders. An optimal leader set can be found by an exhaustive
search over all possible leader sets; however, this approach is not scalable to
large networks. In recent years, several works have proposed approximation
algorithms to the -leader selection problem, yet the question of whether
there exists an efficient, non-combinatorial method to identify the optimal
leader set remains open. This work takes a first step towards answering this
question. We show that, in one-dimensional weighted graphs, namely path graphs
and ring graphs, the -leader selection problem can be solved in polynomial
time (in both and the network size ). We give an solution for
optimal -leader selection in path graphs and an solution for
optimal -leader selection in ring graphs.Comment: 7 pages, 5 figures, submitted to ECC1
Formation control of non-identical multi-agent systems
The problem considered in this work is formation control for non-identical linear multi-agent systems (MASs) under a time-varying communication network. The size of the formation is scalable via a scaling factor determined by a leader agent. Past works on scalable formation are limited to identical agents under a fixed communication network. In addition, the formation scaling variable is updated under a leader-follower network. Differently, this work considers a leaderless undirected network in addition to a leader-follower network to update the formation scaling variable. The control law to achieve scalable formation is based on the internal model principle and consensus algorithm. A biased reference output, updated in a distributed manner, is introduced such that each agent tracks a different reference output. Numerical examples show the effectiveness of the proposed method
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