Abstract-The main contribution of this paper is an improved algorithm for the GRAPH-CLEAR problem, a novel NP-complete graph theoretic problem we recently introduced as a tool to model multi-robot surveillance tasks. The proposed algorithm combines two previously developed solving techniques and produces strategies that require less robots to be executed. We provide a theoretical framework useful to identify the conditions for the existence of an optimal solution under special circumstances, and a set of mathematical tools characterizing the problem being studied. Finally we also identify a set of open questions deserving more investigations. The use of multi-robot systems for the surveillance of vast regions is one of the well established areas in multi-robot research. Up to now, however, there have been still very few on-field deployments of these systems for real world applications. Besides the obvious matter of cost, another reason for their moderate use is the fact that many basic questions about the efficient coordination of these systems are still unanswered. A big fraction of former theoretical research developed models where robots were equipped with sensors abstractions pretty far from realistic applications, e.g. sensors with infinite range and the alike. In this paper we instead extend our previous findings aimed to investigate surveillance tasks by multi-robot systems where individual agents use sensors with limited capabilities. We started this research thread with two papers [5] [6] aimed to extend the CMOMMT (Cooperative Multi-robot Observation of Multiple Moving Targets) problem initially posed by Parker [11] . One of the main limitations of these algorithms is the requirement that robots operate in open areas. Our following efforts have therefore been devoted to scenarios where robots operate in cluttered environments [7] . In particular, we modeled the problem of discovering multiple intruders in a complex environment using a novel graph theoretic problem, dubbed GRAPH-CLEAR. Informally speaking, the problem asks what is the minimum number of robots needed to detect all possible intruders in a given complex environment that can be modeled as a graph. In [8] we proved that the associated decision problem is NP-complete. As clarified later on, a way to circumvent the intractability of the problem on graphs, is to perform certain guard operations that turn graphs into trees. In [7] and [8] we have provided two algorithms that produce search strategies for trees, i.e. course of actions for a robot team that ensures each intruder will be discovered. Both algorithms are known to be suboptimal. In this paper
Kolling and Carpin REF present an algorithm to find the minimum number of robots needed to detect possible intrusions, in indoor environments with many rooms connected by multiple doors.
Multi-robot surveillance: An improved algorithm for the GRAPH-CLEAR problem
2008 IEEE International Conference on Robotics and Automation
2008 IEEE International Conference on Robotics and Automation
Computer Science