The simple grid polygon exploration problem


This paper considers an on-line exploration problem. We use a mobile robot to explore an unknown simple grid polygon. The robot is assumed to have limited sensing capability that can only detect the four basic cells adjacent to it. The robot’s task is to explore each cell and to return to the start. To explore a cell, the robot has to enter it. We ask for a short exploration tour, that is, minimizing the number of multiple-visit cells. The competitive ratio is used to measure the performance of our strategy. It is the ratio between the length of the on-line exploration path and the length of the shortest path achieved with full knowledge of the polygon. As our main result, we present a new on-line exploration strategy and prove that the robot’s path is at most 7/6 times longer than the shortest path. This matches the previously known lower bound.

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Correspondence to Qi Wei or Yonggong Ren.

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This work was supported in part by National Natural Science Foundation of China (No. 61702242, 61976109) and Doctoral Scientific Research Foundation of Liaoning Province (No. 2019-BS-153, 2019-BS-014).

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Wei, Q., Sun, J., Tan, X. et al. The simple grid polygon exploration problem. J Comb Optim (2021).

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  • Path planning
  • On-line Exploration
  • Competitive analysis
  • Grid polygon
  • Mobile robot