The robot is an autonomous surface vehicle equipped with Wi-Fi for communication, and a compass and GPS for navigation.

<p>It has a length of 60 cm and can move at speeds of up to 1.7 m/s.</p

The control synthesis and performance assessment process for each task.

<p>The control synthesis and performance assessment process for each task.</p

Robustness experiments with Controller 1 of the monitoring behavior.

<p>The time regions highlighted in red correspond to the periods when robots where either entering or leaving the monitoring area.</p

Robustness experiments with Controller 3 of the dispersion behavior.

<p>The red area represents the period where the robots of <i>G</i>_<i>b</i> are disturbing the dispersion of <i>G</i>_<i>a</i>, and the black vertical line at <i>t</i> = 180 s indicates the point where the robots in <i>G</i>_<i>b</i> start dispersing, and where the distance error starts being measured for all eight robots.</p

Panoramic photo of the location the experiments at Parque das Nações, Lisbon, Portugal.

<p>Panoramic photo of the location the experiments at Parque das Nações, Lisbon, Portugal.</p

The robotic swarm with 10 units performing a homing task.

<p>The robotic swarm with 10 units performing a homing task.</p

Real-world homing experiments with eight robots.

<p>The robots started around S. The active waypoint was then changed at 60 second intervals, in the order A→B→C→B, for a total of four minutes per experiment. Top: comparison between the real and simulated robots, showing the average distance to the active waypoint, for similar conditions. The top of the figure shows the current active waypoint. Bottom: trajectories of the real robots for Controller 3. The waypoints are marked with yellow circles.</p

Real-world monitoring experiments with eight robots for Controller 1, over a period of five minutes.

<p>Top: coverage of the three different monitoring areas. Bottom: coverage maps in the experiments with the real swarm. The coverage of the area is presented in blue, and has a decay of 100 s. Trajectories for the full duration of the task are presented in red, and all the areas visited by the robots are filled in gray.</p

Results for the multi-controller mission.

<p>Top: robot trajectories for each sub-task. Middle and bottom: temperatures in the monitoring area. Measurements taken by the robots’ temperature sensors were spatially interpolated using kriging [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0151834#pone.0151834.ref071" target="_blank">71</a>]. Data collection started after the robots arrived at the waypoint (<i>t</i> = 100 s). The middle row shows the predicted temperatures, while the bottom row shows the estimated error of the predictions.</p

Illustration of the three types of sensors.

<p>Illustration of the three types of sensors.</p