Abstract
Task partitioning consists in dividing a task into sub-tasks that can be tackled separately. Partitioning a task might have both positive and negative effects: On the one hand, partitioning might reduce physical interference between workers, enhance exploitation of specialization, and increase efficiency. On the other hand, partitioning may introduce overheads due to coordination requirements. As a result, whether partitioning is advantageous or not has to be evaluated on a case-by-case basis. In this paper we consider the case in which a swarm of robots must decide whether to complete a given task as an unpartitioned task, or utilize task partitioning and tackle it as a sequence of two sub-tasks. We show that the problem of selecting between the two options can be formulated as a multi-armed bandit problem and tackled with algorithms that have been proposed in the reinforcement learning literature. Additionally, we study the implications of using explicit communication between the robots to tackle the studied task partitioning problem. We consider a foraging scenario as a testbed and we perform simulation-based experiments to evaluate the behavior of the system. The results confirm that existing multi-armed bandit algorithms can be employed in the context of task partitioning. The use of communication can result in better performance, but in may also hinder the flexibility of the system.
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Notes
In the experiments, α is set to 0.5, refer to Sect. 5 for details.
In our previous work, we selected for each algorithm one method for computing the threshold. In this study we use for each algorithm the corresponding method that was selected in the previous work (refer to Sect. 5).
Notice that γ and η are not constants, due to their dependency on n D +n H .
Each control cycle lasts 0.1 seconds.
Acronym for first in, first out.
The TAMs can communicate via WiFi. The behavior of a cache slot, that is, the coordination between two paired TAMs, can be easily implemented in the real-world by interfacing the TAMs with a PC.
An analogous plot for Exp3 is available in Pini et al. (2012c).
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Acknowledgements
The research leading to the results presented in this paper has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement n∘ 246939. Giovanni Pini acknowledges support from Université Libre de Bruxelles through the “Fonds David & Alice Van Buuren”. Arne Brutschy, Marco Dorigo, and Mauro Birattari acknowledge support from the Belgian F.R.S.–FNRS.
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Pini, G., Gagliolo, M., Brutschy, A. et al. Task partitioning in a robot swarm: a study on the effect of communication. Swarm Intell 7, 173–199 (2013). https://doi.org/10.1007/s11721-013-0078-7
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DOI: https://doi.org/10.1007/s11721-013-0078-7