Symmetry breaking in the plane: Rendezvous by robots with unknown attributes

Jurek Czyzowicz, Leszek Gasieniec, Ryan Killick, Evangelos Kranakis

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We study a fundamental question related to the feasibility of deterministic symmetry breaking in the infinite Euclidean plane for two robots that have minimal or no knowledge of the respective capabilities and "measuring instruments'' of themselves and each other. Assume that two anonymous mobile robots are placed at different locations at unknown distance d from each other on the infinite Euclidean plane. Each robot knows neither the location of itself nor of the other robot. The robots cannot communicate wirelessly, but have a certain nonzero visibility radius r (with range r unknown to the robots). By rendezvous we mean that they are brought at distance at most r of each other by executing symmetric (identical) mobility algorithms. The robots are moving with unknown and constant but not necessarily identical speeds, their clocks and pedometers may be asymmetric, and their chirality inconsistent. We demonstrate that rendezvous for two robots is feasible under the studied model iff the robots have either: different speeds; or different clocks; or different orientations but equal chiralities. When the rendezvous is feasible, we provide a universal algorithm which always solves rendezvous despite the fact that the robots have no knowledge of which among their respective parameters may be different.

Original languageEnglish (US)
Title of host publicationPODC 2019 - Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing
PublisherAssociation for Computing Machinery
Pages4-13
Number of pages10
ISBN (Electronic)9781450362177
DOIs
StatePublished - Jul 16 2019
Externally publishedYes
Event38th ACM Symposium on Principles of Distributed Computing, PODC 2019 - Toronto, Canada
Duration: Jul 29 2019Aug 2 2019

Publication series

NameProceedings of the Annual ACM Symposium on Principles of Distributed Computing

Conference

Conference38th ACM Symposium on Principles of Distributed Computing, PODC 2019
CountryCanada
CityToronto
Period7/29/198/2/19

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Keywords

  • Anonymous
  • Asymmetric clock
  • Chirality
  • Competitive ratio
  • Infinite plane
  • Mobile robot
  • Speed

ASJC Scopus subject areas

  • Software
  • Hardware and Architecture
  • Computer Networks and Communications

Cite this

Czyzowicz, J., Gasieniec, L., Killick, R., & Kranakis, E. (2019). Symmetry breaking in the plane: Rendezvous by robots with unknown attributes. In PODC 2019 - Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing (pp. 4-13). (Proceedings of the Annual ACM Symposium on Principles of Distributed Computing). Association for Computing Machinery. https://doi.org/10.1145/3293611.3331608