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HARDWARESIMULATIONSCONTROL

Control >> Aggregation >> Center Periphery

Centre/Periphery Pattern Formation

Centre/periphery patterns are observed in ant colonies and animal societies. For example, soldier ants create a periphery around the trail protecting the other ants that are bringing food to the nest. Inside the nests of social insects, the specialists are segregated (two or more concentric rings) or form a cluster at the centre of the swarm. In some species of birds and mammals, cubs are usually kept at the centre of the group, protected by a ring of adults.

Designing Centre/Periphery Formation

Two different types of s-bots are used for centre/periphery formation:
  • Centre s-bots (red ones in the pictures) are mainly attracted by sound. They turn their speaker on with a very low probability when they are not connected. When they are surrounded from different directions tightly, they try to connect to surrounding robots for the formation of a stable centre. If centre s-bots are connected to others, their sound emission probability increases in order to inform other s-bots that the centre cluster is formed.
  • Periphery s-bots (blue ones) are attracted by sound like centre s-bots. They connect whenever it is possible but there are two different situations in which they disconnect: first, when periphery s-bots are connected to some other s-bots and they are not located in the border of any cluster. Second, when a periphery s-bot is approached from back by a centre s-bot. In this case, the periphery s-bot must disconnect and allow the centre s-bot to go into cluster. After that, the periphery s-bot may connect again. In both situations, periphery s-bots should disconnect first, be repelled by the cluster, randomly move around for a certain period and then return to the cluster.
Snapshot of the initial position of a center/periphery pattern formation. Snapshot of the final position of a center/periphery pattern formation.
initial positions final positions

See the movie (MPEG, 7.5Mb)


Control >> Aggregation >> Center Periphery

Swarm-bots project started
on October 1,2001
The project terminated
on March 31, 2005.
Last modified:
Fri, 27 Jun 2014 11:26:47 +0200
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