Lab Papers (GRASP)

Document Type

Journal Article

Date of this Version

8-2009

Comments

Copyright 2009 IEEE.
Reprinted from:
Berman, S.; Halasz, A.; Hsieh, M.A.; Kumar, V., "Optimized Stochastic Policies for Task Allocation in Swarms of Robots," Robotics, IEEE Transactions on , vol.25, no.4, pp.927-937, Aug. 2009
URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=5161293&isnumber=5191252

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Abstract

We present a scalable approach to dynamically allocating a swarm of homogeneous robots to multiple tasks, which are to be performed in parallel, following a desired distribution. We employ a decentralized strategy that requires no communication among robots. It is based on the development of a continuous abstraction of the swarm obtained by modeling population fractions and defining the task allocation problem as the selection of rates of robot ingress and egress to and from each task. These rates are used to determine probabilities that define stochastic control policies for individual robots, which, in turn, produce the desired collective behavior. We address the problem of computing rates to achieve fast redistribution of the swarm subject to constraint(s) on switching between tasks at equilibrium. We present several formulations of this optimization problem that vary in the precedence constraints between tasks and in their dependence on the initial robot distribution. We use each formulation to optimize the rates for a scenario with four tasks and compare the resulting control policies using a simulation in which 250 robots redistribute themselves among four buildings to survey the perimeters.

Keywords

Markov processes, distributed control, multi-robot systems, optimisation, stochastic systems, Markov processes, decentralized strategy, distributed control, homogeneous swarm robots, optimization problem, optimized stochastic policies, stochastic systems, task allocation, Distributed control, Markov processes, optimization, stochastic systems, swarm robotics, task allocation

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Date Posted: 30 September 2009

This document has been peer reviewed.