Tolerance to changes in normal robot swarm behavior.

<p>Proportion of false-positive incidents across the 20 robots of the multirobot system, in each of 20 replicates, and two transitions in normal behavior: (A) aggregation to dispersion to aggregation, (B) dispersion to flocking to dispersion, and (C) flocking to homing to flocking. Robots transitioned between the swarm behaviors in intervals of 0 s (instantaneously across the swarm), 12.5 s, and 25 s, in three separate and independent experimental setups.</p

Types of faults, simulated on one robot, selected at random from the swarm.

<p>Types of faults, simulated on one robot, selected at random from the swarm.</p

Types of data packets for inter-robot communication.

<p>A depiction of the data packet (4 bytes) transmitted by the range-and-bearing device of the robot. The first byte (shaded) identifies the header of feature vectors of observed robots, normal/abnormal votes on estimated feature vectors, and coalition information on observed robots. The remaining three bytes comprise the actual message, corresponding to each observed robot (feature vector and coalition packet types), and each observed feature vector (voter packet type).</p

Foraging experiment setup for heterogeneously behaving swarm of 20-e-puck robots.

<p>A: The 9 m² arena comprising a nest site, and the foraging space with a randomly placed resource site. B: Finite state machine diagram controlling each and every robot of the swarm.</p

Fault detection for homogeneously behaving robot swarm.

<p>Proportion of time the faulty robot is detected across 20 replicates, in each of the 28 distinct combinations of normal (aggregation, dispersion, flocking and homing) homogeneous swarm behaviors, and fault types (PMIN, PMAX, PRND, ROFS, LACT, RACT, and BACT). On each box, the mid-line marks the median, and the box extends from the lower to upper quartile below and above the median. Whisker outside the box indicate the maximum and minimum values, except in case of outliers, which are shown as crosses. Outliers are data points outside of 1.5 times the interquartile range.</p

Fault detection for heterogeneously behaving robot swarm.

<p>Proportion of time the faulty robot is detected across 20 replicates, in each of the seven distinct combinations of normal (cooperative foraging) swarm behavior, and fault types (PMIN, PMAX, PRND, ROFS, LACT, RACT, and BACT).</p

Parameters of the crossregulation model.

<p>Parameters of the crossregulation model.</p

Tolerance to normal robot swarm behavior.

<p>Mean and variation in proportion of time robots tolerated, across the 20 robots of the multirobot system, in each of 20 replicates, and five normal behaviors: (A) aggregation (circles), (B) dispersion (crosses), (C) homing towards stationary landmark (pluses), (D) flocking (squares), and (E) cooperative foraging (asterisks).</p

Tolerance to perturbations in the foraging environment.

<p>The robots were first perturbed to a foraging environment comprising an absence of resources (Stage 1 to Stage 2), and subsequently to an environment with an abundance of resources (Stage 2 to Stage 3): (A) Median ± IQR of robots exhibiting distinct behaviors of exploration, signaling, retrieval of resources at foraging site, and returning foraged resource to the nest, all during cooperative foraging, and (B) the proportion of false-positive incidents across the 20 robots of the swarm, in each of 20 replicates.</p

Parameters of the robot swarm.

<p>Parameters of the robot swarm.</p