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   Physics-Based Control of Swarm LEGO® Robots   [View] 
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 Author(s)   Robert Gasowski 
 Abstract   Author introduces a framework based on LEGO® “MINDS STORM®” robots, called “Robo-ant”, that provides distributed control of large collection of mobile physical robots in sensor networks. The robots sense and will react to virtual forces, which are motivated by natural physics laws. This framework provides an effective basis for self-organization, fault-tolerance, and three primary factors will distinguish our framework from others that are related: an emphasis on minimality, ease of implementation and run-time efficiency. “Robo-ant” will be implement both in simulation and on a team of three mobile LEGO© robots and CC1000DK Development kit (remote transmitter/receiver). Specifics of the robotics bodiment are presented in the paper. The focus of author research is to design and build rapidly deployable, scalable, adaptive, cost-effective, and robust networks of autonomous distributed LEGO® vehicles. This combines sensing, computation and networking with mobility, thereby enabling deployment, and reconfiguration of the multiagent collective. Author objective is to provide a scientific, approach to the design and analysis of aggregate sensor systems. The general purpose for deploying tens to hundreds of such agents can be summarized as “factor control”. Factor control means monitoring, detecting, tracking, reporting, and responding to environmental conditions within a specified physical region. This is done in a distributed manner by deploying numerous vehicles, each carrying one or more sensors, to collect, aggregate, and fuse distributed data into a tactical assessment. The result is enhanced situational awareness and the potential for rapid and appropriate response. Author goal is to design fully automated, coordinated, multi-agent sensor systems. An agent’s sensors perceive theworld, including other agents, and an agent’s effectors make changes to that agent and/or the world, including other agents. It is assumed that agents can only sense and affect nearby agents; thus, a key challenge has been to design “local” control rules. Not only do author want the desired global behavior to emerge from the local interaction between agents (self-organization), but also require fault-tolerance, that is, the global behavior degrades very gradually if individual agents are damaged. Self-repair is also desirable, in the event of damage. Self-organization, faulttolerance, and self-repair are precisely those principles exhibited by natural physical systems. Thus, many answers to the problems of distributed control can be found in the natural laws of physics. This paper presents a framework, called “Roboant”. Although the forces will be virtual, agents act as if they were real. Thus the agent’s sensors must see enough to allow it to compute the force to which it is reacting. The agent’s effectors must allow it to respond to this perceived force. Author see two potential advantages to this approach. First, in the real physical world, collections of small entities yield surprisingly complex behavior from very simple interactions between the entities. Thus there is a precedent for believing that complex control is achievable through simple local interactions. This is required for very small agents, since their sensors and effectors will necessarily be primitive. Second, since the approach is largely independent of the size and number of agents, the results scale well to larger agents and larger sets of agents. Three primary emphases distinguish the “Robo-ant” framework from others that are related: minimality, ease of implementation, and runtime efficiency. First, robots formations will be achieved with a minimal set of sensors and sensor information. The rationale for this emphasis is that it will: (1) reduce overall vehicle cost, (2) enable physical embodiment with small agents, and (3) increase vehicle stealthiness if sensing is active. Second, the paper presents the toretical results that translate directly into practical advice on how to set system parameters for desired swarm performance. This makes the robotic implementation straightforward. 
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Filename:171
Filesize:405.3 KB
 Type   Members Only 
 Date   Last modified 2006-02-08 by System