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Control >> Cooperative transport >> Blind and non-blind s-bots

Transport by swarms of blind and non-blind s-bots

In this study we focus on the situation in which some robots of the transport group are given the opportunity to localise the target, while the others (called the blind ones) are not. We propose the use of relatively simple robots capable of self-assembling into structures which pull or push the prey. To enable a blind robot to contribute to the group's performance, it can locally perceive traction forces, and whether it is moving or not.



A simulation lasts 35 simulated seconds. At any point in time, there is only one beacon (selected randomly) emitting light indicating the target location. Initially, the prey is put in the centre, and N s-bots are placed at random positions and with random orientations no more than 50 cm from the prey. The s-bot controllers are supposed to let the s-bots localise and approach the prey, self-assemble into structures, each of them physically linked to the prey, and pull or push the prey towards the light-emitting beacon. Task

Experimental setup

We have decomposed the problem of control at the level of an s-bot into sub problems:
  • assembly,
  • transport by non-blind s-bots,
  • transport by blind s-bots.

The robot group is controlled in a distributed manner, using this modular control architecture. We investigated a collection of simple hand-coded and artificially evolved control modules.

Results

We have considered groups of 2 to 16 s-bots. The mass of the prey is kept proportional to the group size. The performance measure we use is the distance the prey gains wrt to the target location during the entire simulation period (35 seconds).

Unless no robot was able to localise the target, having blind robots controlled by an evolved individual was superior in performance to the alternative of removing them from the experiment. On the contrary, in most of the trials, controlling the blind s-bots by the hand-coded solutions was inferior in performance to the alternative of removing them from the experiment. If no more than half of the robots were blind, the contribution of the blind robots, if controlled by the best evolved controller, was 40 to 60% of the contribution non-blind robots would provide (in average) if put in the same situation.

For the best evolved solution the performance seems to scale well with group size, which should make it possible to transport heavier prey by larger swarms of robots.


References



Control >> Cooperative transport >> Blind and non-blind s-bots

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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