Deployment of Robotic Sensors

An important problem for systems of wireless sensor is the effective deployment of the sensor within the target space S. the deployment have to satisfy some optimization criteria with respect to the space S. they are usually deployed by external means in case of static sensors, either carefully or randomly; the distribution of the sensors may not satisfy the desired optimization criteria in the latter case.

If the sensing entities are mobile, as in the case of mobile sensor networks, robotic sensor networks and vehicular networks, they are potentially capable to position themselves in appropriate locations without the help of any external control or central coordination. However to achieve such an aim is a rather complex task, and designing localized algorithms for effective and efficient deployment of the mobile sensors is a challenging research issue.

We are interested in a specific instance of the problem, called the Uniform Dispersal problem, where the sensors have to fill completely an unknown space S entering through one or more designated entry point called doors. The sensors must avoid colliding with each other, have to terminate within finite time. The space S is assumed to be simply connected, without holes, and orthogonal, e.g. polygonal with slides either perpendicular or parallel to one another. Orthogonal spaces are interesting because Orthogonal spaces can be used to model indoor and urban environment.

It considers the problem within the context of robotics sensor network: the mobile entities rely only on sensed local information within a restricted radius, called visibility range; when active they operate in a sense-compute-move cycle; and they usually have no explicit means of communication.

A crucial difference between traditional wireless sensor networks and robotic sensor networks is in the determination of an entity’s neighbors. In robotic sensor networks, the determination of one neighbor is done by sensing capabilities, i.e. vision: any sensor in the sensing radius will be detected even if inactive.