Swarm robotics for a dynamic cleaning problem

Abstract

Several recent works considered multi agents robotics in static environments (e.g.[2], [4], [5] and others). In this work we examine ways of operating in dynamic environments, in which changes may take place regardless of the agents' activity. The work focuses on a dynamic variant of the known Cooperative Cleaners problem (described and analyzed in [2]). This problem assumes a grid, part of which is "dirty", when the "dirty" part is a connected region of the grid. On this dirty region several agents move, each having the ability to "clean" the place it is located in. The dynamic variant of the problem involves a deterministic evolution of the environment, simulating a spreading contamination, or fire. A cleaning protocol for the problem is presented, as well as several analytic bounds for it. In addition, the work contains simulative results for the proposed protocol.

COLLABORATIVE EXPLORATION IN GRID DOMAINS - Constructive Conjecture of a Polynomial Time Complexity

“…The cooperative cleaners problem was previously studied in (Wagner et al, 2008) (static version) and (Altshuler et al, 2005a;Altshuler et al, 2009) and others (dynamic version). A cleaning algorithm was proposed (used by a decentralized group of simple mobile agents, for exploring and cleaning an unknown "contaminated" sub-grid F, expanding every d time steps) and its performance analyzed.…”

Shape Factor’s Effect on a Dynamic Cleaners Swarm

“…Having no additional information, this can be guaranteed by assuming that whenever the contamination spreads, it is somehow organized as a digital sphere (as was the case in the bound presented in [1]). This, however, is rarely the case, since in the course of the expansions and erosion process of the contamination, the probability for the contaminated region to be accidently maintained in the form of a digital sphere, is very low.…”

“…On this dirty grid region several agents move, each having the ability to 'clean' the place ('tile', 'pixel' or 'square') it is located in (similar works appear in [15][16][17]). The dynamic variant of the cooperative cleaners problem (presented in [1] and described in section 2) involves a deterministic evolution of the environment, simulating a spreading contamination (or spreading fire). Once again, the goal of the agents is to clean the spreading contamination in as little time as possible.…”

“…A cooperative swarm cleaning protocol for the problem and a basic analysis of, as well as various experimental results are presented in [1], whereas a comparison of this swarm protocol to an A * based omniscient centralized algorithm is discussed in [19]. A scheme of a cooperative hunting protocol, designed to be used by a swarm of unmanned air vehicles seeking evading targets, which is based on the cleaning protocol mentioned above is described in [2].…”

“…The "contaminated" tiles expand deterministically, simulating a spreading of contamination, or fire. This problem, as well as a cooperative cleaning protocol for it and its analysis, were first introduced in [1]. The equivalence of this problem to another interesting multi agents problem was demonstrated in [2] by utilizing results relevant to the problem in order to design a cooperative hunting protocol for a swarm of UAVs.…”