Coordinating Distributed Autonomous Agents with a Real-Time Database: The CAMBADA Project

Abstract

Interest on using mobile autonomous agents has been growing, recently, due to their capacity to cooperate for diverse purposes, from rescue to demining and security. However, such cooperation requires the exchange of state data that is time sensitive and thus, applications should be aware of data temporal coherency. In this paper we describe the architecture of the agents that constitute the CAMBADA robotic soccer team developed at the University of Aveiro, Portugal. This architecture is built around a real-time database that is partially replicated in all team members and contains both local and remote state variables. The temporal coherency of the data is enforced by an adequate management system that refreshes each database item transparently at a rate specified by the application. The application software accesses the state variables of all agents with local operations, only, delivering both value and temporal coherency.

CAMBADA Soccer Team: from Robot Architecture to Multiagent Coordination

“…The players are capable of holonomic motion, based on three omni-directional roller wheels. The general architecture of the CAMBADA robots has been described in (Almeida et al, 2004;Silva et al, 2005). Basically, the robots follow a biomorphic paradigm, each being centered on a main processing unit (a laptop), the brain, which is responsible for the higher-level behavior coordination, i.e.…”

“…15). We call this replicated blackboard the Real-time Data Base (RTDB), (Almeida et al, 2004) which holds the state data of each agent together with local images of the relevant state data of the other team members. A specialized communication system triggers the required transactions at an adequate rate to guarantee the freshness of the data.…”

“…The project started in 2003, coordinated by the Transverse Activity on Intelligent Robotics group of the Institute of Electronic and Telematic Engineering of Aveiro (IEETA). This project involves people working on several areas for building the mechanical structure of the robot, its hardware architecture and controllers (Almeida et al, 2002;Azevedo et al, 2007) and the software development in areas such as image analysis and processing (Caleiro et al, 2007;Cunha et al, 2007;Martins et al, 2008;Neves et al, 2007;, sensor and information fusion (Silva et al, 2008;, reasoning and control , cooperative sensing approach based on a Real-Time Database (Almeida et al, 2004), communications among robots (Santos et al, 2009; and the development of an efficient basestation. The main contribution of this chapter is to present the new advances in the areas described above involving the development of an MSL team of soccer robots, taking the example of the CAMBADA team that won the RoboCup 2008 and attained the third place in the last edition of the MSL tournament at RoboCup 2009.…”

Communicating among Robots in the RoboCup Middle-Size League

“…DataBase (RTDB) middleware, originally developed in 2004 [7], and the reconfigurable adaptive-TDMA protocol described in [8]. The RTDB middleware targets providing an efficient and timely support for the fusion of the distributed perception and the development of coordinated behaviors by providing a seamless access to the complete team state using a distributed database that is partially replicated in all team members.…”

Control and Monitoring of a Robotic Soccer Team: The Base Station Application

“…At each communication cycle the agents report their internal state creating a virtual representation, shared by all, of the global WorldState. This virtual representation is named Real-Time DataBase (RTDB) [10]. This mechanism simplifies the information management and access.…”