Abstract not found

Abstract — Monitoring of environmental phenomena with embedded networked sensing confronts the challenges of both unpredictable variability in the spatial distribution of phenomena, coupled with demands for a high spatial sampling rate in three dimensions. For example, low distortion mapping of critical solar radiation properties in forest environments may require two-dimensional spatial sampling rates of greater than 10 samples/m 2 over transects exceeding 1000 m 2. Clearly, adequate sampling coverage of such a transect requires an impractically large number of sensing nodes. This paper describes a new approach where the deployment of a combination of autonomous-articulated and static sensor nodes enables sufficient spatiotemporal sampling density over large transects to meet a general set of environmental mapping demands. To achieve this we have developed an embedded networked sensor architecture that merges sensing and articulation with adaptive algorithms that are responsive to both variability in environmental phenomena discovered by the mobile sensors and to discrete events discovered by static sensors. We begin by describing the class of important driving applications, the statistical foundations for this new approach, and task allocation. We then describe our experimental implementation of adaptive, event aware, exploration algorithms, which exploit our wireless, articulated sensors operating with deterministic motion over large areas. Results of experimental measurements and the relationship among sampling methods, event arrival rate, and sampling performance are presented.

Abstract not found

Abstract not found

Despite more than a decade of experimental work in multi-robot systems, important theoretical aspects of multi-robot coordination mechanisms have, to date, been largely untreated. To address this issue, we focus on the problem of multi-robot task allocation (MRTA). Most work on MRTA has been ad hoc and empirical, with many coordination architectures having been proposed and validated in a proof-of-concept fashion, but infrequently analyzed. With the goal of bringing objective grounding to this important area of research, we present a formal study of MRTA problems. A domain-independent taxonomy of MRTA problems is given, and it is shown how many such problems can be viewed as instances of other, well-studied, optimization problems. We demonstrate how relevant theory from operations research and combinatorial optimization can be used for analysis and greater understanding of existing approaches to task allocation, and show how the same theory can be used in the synthesis of new approaches.

Multi-Robot Systems (MRS) are, nowadays, an important research area within Robotics and Artificial Intelligence and a growing number of systems has been recently presented in the literature. Since application domains and tasks that are faced by MRS are of increasing complexity, the ability of the robots to cooperate can be regarded as a fundamental feature. In this paper, we present a survey of the recent work in the area by specifically examining the forms of cooperation and coordination realized in the MRS. In particular, we propose a new taxonomy for classification of the approaches to coordination in MRS and we describe some systems, which we consider representative in our taxonomy. We finally discuss the outcomes of our analysis and try to highlight future trends of the research on MRS.

We present a Multi Field Distributed In-network Task Allocation (DINTA-MF) algorithm for online multi-robot task allocation (OMRTA) where tasks are allocated explicitly to robots by a pre-deployed, static sensor network. The idea of DINTA-MF is to compute several assignment fields in the sensor network and then distributively assign fields to different robots. Experimental results with a simulated alarm scenario show that our approach is able to compute solutions to the OMRTA problem in a distributed fashion and arguably in an optimal way. We compared DINTA-MF with a simpler implementation (DINTA) which uses one assignment field. The data show that DINTA-MF outperforms DINTA as the number of robots increases.

Although many multi-robot task allocation (MRTA) architectures can be found in the literature, relatively little has been said regarding the fundamental theoretical characteristics of the task allocation problem. We present a formal, but practical, framework for studying MRTA. In constructing our framework, we borrow from the Operations Research community and show that MRTA can be understood as an instance of the Optimal Assignment Problem. We use this framework to analyze several recently proposed approaches to MRTA, describing their fundamental characteristics in such a way that they can be objectively studied, compared, and evaluated. In so doing, we demonstrate the utility of such frameworks in formalizing robotics research, which we argue is vital to the development of the field.

Abstract — To enable the successful deployment of taskachieving multi-robot systems (MRS), coordination mechanisms must be utilized in order to effectively mediate the interactions between the robots and the task environment. Over the past decade, there have been a number of elegant experimentally demonstrated MRS coordination mechanisms. Most of these mechanisms have been task-specific in nature, typically providing only empirical insights into coordination design and little in the way of systematic techniques to assist in the design of coordinated MRS for new task domains. To fully realize the potentials of MRS, formally-grounded systematic techniques amenable to analysis are needed in order to facilitate the design of coordinated MRS. We address this problem by presenting a formal framework for describing and reasoning about coordination in a MRS. Using this principled foundation, we are developing a suite of general methods for automatically synthesizing the controllers of robots constituting a MRS such that the given task is performed in a coordinated fashion. This paper presents a method for the automatic synthesis of a specific type of controller, one that is stateless but capable of inter-robot communication. We also present a graph coloring-based approach for minimizing the number of necessary unique communication messages. The synthesis of such communicative controllers provides a means for assessing the uses and limitations of communication in MRS coordination. We present experimental validation of our formal approach of controller synthesis in a multi-robot construction domain through physically-realistic simulations and in real-robot demonstrations. I.

Abstract — Efficient exploration of unknown environments is a fundamental problem in mobile robotics. In this paper we present an approach to distributed multi-robot mapping and exploration. Our system enables teams of robots to efficiently explore environments from different, unknown locations. In order to ensure consistency when combining their data into shared maps, the robots actively seek to verify their relative locations. Using shared maps, they coordinate their exploration strategies so as to maximize the efficiency of exploration. Our system was evaluated under extremely realistic real-world conditions. An outside evaluation team found the system to be highly efficient and robust. The maps generated by our approach are consistently more accurate than those generated by manually measuring the locations and extensions of rooms and objects. I.