Skip to main content

Cost-Based Target Selection Techniques Towards Full Space Exploration and Coverage for USAR Applications in a Priori Unknown Environments


Full coverage and exploration of an environment is essential in robot rescue operations where victim identification is required. Three methods of target selection towards full exploration and coverage of an unknown space oriented for Urban Search and Rescue (USAR) applications have been developed. These are the Selection of the closest topological node, the Selection of the minimum cost topological node and the Selection of the minimum cost sub-graph. All methods employ a topological graph extracted from the Generalized Voronoi Diagram (GVD), in order to select the next best target during exploration. The first method utilizes a distance metric for determining the next best target whereas the Selection of the minimum cost topological node method assigns four different weights on the graph’s nodes, based on certain environmental attributes. The Selection of the minimum cost sub-graph uses a similar technique, but instead of single nodes, sets of graph nodes are examined. In addition, a modification of A* algorithm for biased path creation towards uncovered areas, aiming at a faster spatial coverage, is introduced. The proposed methods’ performance is verified by experiments conducted in two heterogeneous simulated environments. Finally, the results are compared with two common exploration methods.

This is a preview of subscription content, access via your institution.


  1. Ma, L., Yu, Y., Zhang, Y.: A skeletonization algorithm based on euclidean distance maps and morphological operators. J. Electron. (China) 18(3), 272–276 (2001)

    Google Scholar 

  2. Calisi, D., Farinelli, A., Iocchi, L., Nardi, D.: Autonomous navigation and exploration in a rescue environment. In: Proceedings of the 2nd European Conference on Mobile Robotics (ECMR), pp. 110–115

  3. Stachniss, C., Burgard, W.: Mapping and exploration with mobile robots using coverage maps. In: IEEE/RSJ IROS, pp. 467–472 (2003)

  4. Gonzalez-Banos, H.H., Latombe, J.C: Navigation strategies for exploring indoor environments. Int. J. Robot. Res., 829–848 (2002)

  5. Stachniss, C., Burgard, W.: Mapping and Exploration with Mobile Robots using Coverage Maps. In: Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Las Vegas, pp. 476–481 (2003)

  6. Morales, M., Tapia, L., Pearce, R., Rodriguez, S., Amato, N.M.: A machine learning approach for feature-sensitive motion planning. In: International Workshop on Algorithmic Foundations of Robotics, pp. 361–376 (2004)

  7. Garrido, S., Moreno, L.: Path planning for mobile robot navigation using Voronoi diagram and fast marching. In: International conference on Intelligent robots and systems, pp. 2376–2381 (2006)

  8. Kim, J., Zhang, F., Egerstedt, M.: A provably complete exploration strategy by constructing Voronoi diagrams. In: Autonomous Robots, Nov. 2010, vol. 29, no. 3-4, pp. 367–380

  9. Endo, Y., Arkin, R.C.: Anticipatory robot navigation by simultaneously localizing and building a cognitive map. In: Proceedings of the 2003 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2003), vol. 1, pp. 460–466 (2003)

  10. Konolige, K., Marder-Eppstein, E., Marthi, B.: Navigation in hybrid metric-topological maps. In: 2011 IEEE International Conference on Robotics and Automation (ICRA), pp. 3041–3047

  11. Choset, H.: Coverage for robotics A survey of recent results. Ann. Math. Artif. Intell. 31(1-4), 113–126 (2001)

    MATH  Google Scholar 

  12. Elfes, A.: Sonar-based real-world mapping and navigation. IEEE J. Robot. Autom. 3(3), 249–265 (1987)

    Google Scholar 

  13. Gabriely, Y., Rimon, E.: Spanning-tree based coverage of continuous areas by a mobile robot. Ann. Math. Artif. Intell. 31(1-4), 77–98 (2001)

    MATH  Google Scholar 

  14. Gabriely, Y., Rimon, E.: Competitive on-line coverage of grid environments by a mobile robot. Comput. Geom. 24(3), 197–224 (2003)

    MathSciNet  MATH  Google Scholar 

  15. Agmon, N., Hazon, N., Kaminka, G.A., MAVERICK Group: The giving tree: constructing trees for efficient offline and online multi-robot coverage. Ann. Math. Artif. Intell. 52(2-4), 143–168 (2008)

    MathSciNet  MATH  Google Scholar 

  16. Hert, S., Tiwari, S., Lumelsky, V.: A terrain-covering algorithm for an AUV. In: Underwater Robots, pp. 17–45. Springer US (1996)

  17. Sachs, S., LaValle, S.M., Rajko, S.: Visibility-based pursuit-evasion in an unknown planar environment. The Int. J. Robot. Res. 23(1), 3–26 (2004)

    Google Scholar 

  18. Choset, H.: Coverage of known spaces: The boustrophedon cellular decomposition. Auton. Robot. 9(3), 247–253 (2000)

    Google Scholar 

  19. Tsardoulias, E., Petrou, L.: Critical Rays Scan Match SLAM. J. Intell. Robot. Syst., 1–22 (2013)

  20. Tsardoulias, E.G., Serafi, A.T., Panourgia, M.N., Papazoglou, A., Petrou, L.: Construction of minimized topological graphs on occupancy grid maps based on GVD and sensor coverage information. J. Intell. Robot. Syst. 75(3-4), 457–474 (2014)

    Google Scholar 

  21. Tsardoulias, E.G., Iliakopoulou, A., Kargakos, A., Petrou, L.: A review of global path planning methods for occupancy grid maps regardless of obstacle density. J. Intell. Robot. Syst., 1–30 (2016)

  22. Hart, P.E., Nilsson, N.J., Raphael, B.: A Formal Basis for the Heuristic Determination of Minimum Cost Paths. IEEE Transactions on Systems Science and Cybernetics 4(2), 100–107 (1968)

    Google Scholar 

  23. Carpin, S., Lewis, M., Wang, J., Balakirsky, S., Scrapper, C.: USARSim: A Robot Simulator for Research and Education. In: Proceedings of the IEEE International Conference on Robotics and Automation, 2007, pp. 1400–1405

  24. Gerkey, B.P., Vaughan, R.T., Howard, A.: The Player/Stage Project: Tools for Multi-Robot and Distributed Sensor Systems. In: Proceedings of the Intl. Conf. on Advanced Robotics (ICAR), Coimbra, Portugal, July 2003, pp. 317–323

Download references

Author information

Authors and Affiliations


Corresponding author

Correspondence to E. G. Tsardoulias.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Tsardoulias, E.G., Iliakopoulou, A., Kargakos, A. et al. Cost-Based Target Selection Techniques Towards Full Space Exploration and Coverage for USAR Applications in a Priori Unknown Environments. J Intell Robot Syst 87, 313–340 (2017).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


  • Autonomous robot
  • Exploration
  • Full coverage
  • Costs
  • Topological graph
  • A* algorithm