In this work, we will discuss the design of a team of robots to play soccer at RoboCup E-League. This task is being carried out in the Cognitive Robotics group of the Laboratory of Research and Development in Artificial Intellgence (LIDIA), Department of Computer Science and Engineering, Universidad Nacional del Sur. The RoboCup competition provides a great opportunity to develop a multi-agent system in which we can test and apply new ideas and results. In the following sections, we will briefly describe the league in which we will participate, and our proposal for the implementation of a team.Eje: Inteligencia artificial distribuida, aspectos teóricos de la inteligencia artificial y teoría de computaciónRed de Universidades con Carreras en Informática (RedUNCI

Delladio, Telma

García, Alejandro Javier

García, Diego R.

Gottifredi, Sebastián

Martínez, F. A.

Rotstein, Nicolás D.

Simari, Gerardo I.

Tucat, Mariano

English

Servicio de Difusión de la Creación Intelectual

Cognitive Robotics in a Soccer Game Domain:a Proposal for the E-League CompetitionAlejandro J. Garc´ıa Gerardo I. SimariTelma Delladio Diego R. Garc´ıaMariano Tucat Nicola´s D. RotsteinFernando A. Mart´ın Sebastia´n GottifrediGrupo de Robo´tica CognitivaLaboratorio de Investigacio´n y Desarrollo en Inteligencia Artiﬁcial (LIDIA) 1Departamento de Ciencias e Ingenier´ıa de la Computacio´nUniversidad Nacional del Sur. Av. Alem 1253, (8000) Bah´ıa Blanca, ArgentinaTel: ++54 291 4595135 - Fax: ++54 291 4595136{ajg,gis,td,drg,mt,ndr,fam,sg}@cs.uns.edu.ar1 IntroductionIn this work, we will discuss the design of a team of robots to play soccer at RoboCup E-League[7, 6, 1, 8]. This task is being carried out in the Cognitive Robotics group of the Laboratory ofResearch and Development in Artiﬁcial Intellgence (LIDIA), Department of Computer Scienceand Engineering, Universidad Nacional del Sur. The RoboCup competition provides a greatopportunity to develop a multi-agent system in which we can test and apply new ideas andresults. In the following sections, we will brieﬂy describe the league in which we will participate,and our proposal for the implementation of a team.2 Robocup E-LeagueThe E-League is part of RoboCup Soccer, which provides an entry point for teams that donot have the resources to compete in Small Size or higher leagues. This league’s setup isbased on the Small Size League, and includes common vision and communication software.Figure 1 shows E-League’s support for vision and communication. A video camera overlooksthe ﬁeld, capturing images that are sent to a video server called Doraemon [4]. This programwill process the images, extracting information about each robot and the ball. This informationis condensed in a package with the following format:0 No. obj. Frame no. Time diff.1 CamX CamY CamZ2 Type Name Found? PosX PosY PosZ Orient. VelX VelY... . . . . . . . . . . . . . . . . . . . . . . . . . . .10 Type Name Found? PosX PosY PosZ Orient. VelX VelY1Member of the IICyTI (Instituto de Investigacio´n en Ciencia y Tecnolog´ıa Informa´tica).Line 0 contains the number of objects being identiﬁed by the video server, the current framenumber, and the time diﬀerence between the last two frames. Line 1 contains the (x, y, z)coordinates of the camera with respect to the ﬁeld. Afterwards, the following nine lines containinformation about each of the robots, and the ball. Each of these lines contains the followinginformation:• Object type: ball, robot, etc.• Object name: “ball” for the ball, and an identiﬁer for each robot.• Whether the object was found by the video server or not. In case it wasn’t found, theserver will predict the information for this frame.• The (x, y, z) coordinates of the object.• The object’s orientation, in radians.• The object’s velocity with respect to the x and y directions.This information is then processed by each of the two teams’ agents (see Figure 1), which willbe running on computers which we will call PC Shuttles (one for each team). Communicationfollows a client/server model. Therefore, the agents are clients which receive the video server’spackages by means of the league’s local network. In Figure 1, this can be seen in the connectionfrom Doraemon to PC Shuttle. This completes the “vision path”, which carries perceptualinformation from the environment to the agents.Figure 1: E-League setupFigure 2: A proposed architecture for the implementation of an E-League team.The “eﬀectoric path” also responds to a client/server model, in which the teams are clientsof the Command Server. At every time step, the Command Server gathers commands fromeach of the teams which are sent to the robots on the ﬁeld. The teams send commands ofthe form “[name]:[msg]\n”, where name is the robot’s name, and msg is the message sent toit. The Command Server has a command buﬀer for each robot, which is updated as messagesarrive. Periodically, the Command Server will send these messages to the robots by means ofone or more infra-red transmitters directed towards the ﬁeld. Each robot is capable of receivingthese messages, and obtaining the command that is directed to him.3 Architecture for Team ImplementationWe are currently working on the implementation of a team for competing in Robocup E-League2004 [3]. The organization of this implementation is being carried out in layers, each of whichoﬀers support at a given level of abstraction. The objective of this model is to modularizethe solution to this problem, isolating the diﬀerent aspects that must be solved by means ofthese layers. For instance, the problem of communicating with the vision server should not beintertwined with the task of reasoning about the best strategy for scoring a goal.In the following, we will describe our approach to this separation into layers (see Figure 2):• Low Level Communication Layer: This layer contains the low level communica-tion support provided by the league. This includes infra-red transmitters, video camera,network support, and the software that is necessary for processing visual information(Doraemon) and processing commands that will be sent to the ﬁeld (Command Server).• Logical Communication Layer: Composed by a set of routines that interface the LowLevel Communication Layer with the higher layers. They provide the necessary servicesthat enable communication with the servers.• Sensorial/Efectorial Layer (SEL): In this layer, raw visual information is processedand translated into environment states that reﬂect a higher level of abstraction. Forexample, given a set of coordinates and speed for each of the robots and the ball, thisinformation could be translated into “robot r3 is in position to kick the ball”. Anotherfunction implemented by this layer involves the translation of actions selected by theagents into packets that will be sent to the Command Server.• Cognitive Layer: This layer models the behavior of the team of robots. It containsthe implementation of the agents that represent the team. These agents perceive theenvironment only through the information oﬀered by the SEL. Diﬀerent alternatives arepossible in this layer. For example, one of the choices involves implementing the team as asociety of agents, or as a single agent that controls all of the robots. In the case of a multi-agent model, decisions concerning communication among the agents must be made (directcommunication through messages, blackboards, multi-agent cooperation protocols, etc).3.1 Robotic EquipmentOur team is composed of four robots, built with Lego MindstormsTM [5]. The league onlyimposes restrictions on processor speed and memory size, and this robotic kit falls within theserestrictions with a speed of 10MHz and 32KB of RAM. This equipment can be loaded with avariety of ﬁrmwares, which determine the programming language that can be used. In this case,we will use BrickOS [2] and the C programmig language for the program that will be runningon the robots’ processors. This should not be mistaken with the programs that correspond tothe agents, as we will see in the following section.3.2 Implementation of the Cognitive LayerThe implementation of the Cognitive Layer is currently under development, and it is composedby logic-based agents that will be implemented using Prolog. This approach has a series ofadvantages, such as declarative programming, which allows a more or less direct translationfrom behavior models to the code that will be directly executed by the agents.In this proposal, each agent is implemented by a Prolog program. Based on the environmentinformation provided by the SEL, these agents will reason and select the next action that willbe executed. This decision is communicated to the SEL, which will build a packet that will bereceived by the Command Server via the Logical Communication Layer. Finally, the CommandServer will gather these packets and sends them to the robots on the ﬁeld.Another design issue that must be resolved is the basic set of actions that will be available tothe agents in order to carry out their plans. An important aspect of this decision is the tradeoﬀbetween the length of a given basic action and its reliability. That is, a long basic action avoidsexcessive sensing and deliberation, but is more prone to failure (for example, due to slipping,collision, etc). Therefore, we need to decide which actions will be directly implemented in therobots’ code (which will be activated by messages), and which actions are left as decisions tobe made by the agents as part of their plans.4 ConclusionsIn this work, we have described a proposal for the implementation of a team of robots that willbe participating in the RoboCup E-League competition. We regard this as an opportunity tobuild a multi-agent system in which new research ideas and developments can be tested, such asplanning, knowledge representation, argumentation, and multi-agent cooperation mechanisms.AcknowledgementsWe are very grateful to the Association of Computing Machinery (ACM) for granting us ascholarship that will allow us to cover most of the costs of participating this year in the com-petition in Lisbon, and to Dr. Elizabeth Sklar of the University of Columbia in New York,for making this possible. We are also grateful to the Department of Computer Science andEngineering, Universidad Nacional del Sur, for making its space and resources available to usat any time. The project is also partially supported by the Agencia Nacional de Promocio´nCient´ıfica y Tecnolo´gica (PICT 13096).Finally, Gerardo Simari is partially supported by Comisio´n de Investigaciones Cient´ıficas,(CIC) Gobierno de la Provincia de Buenos Aires. Telma Delladio is partially supported byConsejo Nacional de Investigaciones Cient´ıficas y Te´cnicas (CONICET).References[1] http://agents.cs.columbia.edu/eleague/.[2] http://brickos.sourceforge.net/.[3] http://cs.uns.edu.ar/∼gis/robocup-tdp.htm.[4] http://sourceforge.net/projects/robocup-video.[5] http://www.legomindstorms.com.[6] http://www.robocup2004.pt.[7] http://www.robocup.org.[8] Anderson, J., Baltes, J., Livingston, D., and Sklar, E. Toward an undergraduate leaguefor robocup. In Proceedings of the RoboCup Symposium (2003).

Cognitive robotics in a soccer game domain: a proposal for the e-league competition

SEDICI - Repositorio de la UNLP

Cognitive Robotics in a Soccer Game Domain:
a Proposal for the E-League Competition
Alejandro J. Garc´ıa Gerardo I. Simari
Telma Delladio Diego R. Garc´ıa
Mariano Tucat Nicola´s D. Rotstein
Fernando A. Mart´ın Sebastia´n Gottifredi
Grupo de Robo´tica Cognitiva
Laboratorio de Investigacio´n y Desarrollo en Inteligencia Artificial (LIDIA) 1
Departamento de Ciencias e Ingenier´ıa de la Computacio´n
Universidad Nacional del Sur. Av. Alem 1253, (8000) Bah´ıa Blanca, Argentina
Tel: ++54 291 4595135 - Fax: ++54 291 4595136
{ajg,gis,td,drg,mt,ndr,fam,sg}@cs.uns.edu.ar
1 Introduction
In this work, we will discuss the design of a team of robots to play soccer at RoboCup E-League
[7, 6, 1, 8]. This task is being carried out in the Cognitive Robotics group of the Laboratory of
Research and Development in Artificial Intellgence (LIDIA), Department of Computer Science
and Engineering, Universidad Nacional del Sur. The RoboCup competition provides a great
opportunity to develop a multi-agent system in which we can test and apply new ideas and
results. In the following sections, we will briefly describe the league in which we will participate,
and our proposal for the implementation of a team.
2 Robocup E-League
The E-League is part of RoboCup Soccer, which provides an entry point for teams that do
not have the resources to compete in Small Size or higher leagues. This league’s setup is
based on the Small Size League, and includes common vision and communication software.
Figure 1 shows E-League’s support for vision and communication. A video camera overlooks
the field, capturing images that are sent to a video server called Doraemon [4]. This program
will process the images, extracting information about each robot and the ball. This information
is condensed in a package with the following format:
0 No. obj. Frame no. Time diff.
1 CamX CamY CamZ
2 Type Name Found? PosX PosY PosZ Orient. VelX VelY
... . . . . . . . . . . . . . . . . . . . . . . . . . . .
10 Type Name Found? PosX PosY PosZ Orient. VelX VelY
1Member of the IICyTI (Instituto de Investigacio´n en Ciencia y Tecnolog´ıa Informa´tica).
Line 0 contains the number of objects being identified by the video server, the current frame
number, and the time difference between the last two frames. Line 1 contains the (x, y, z)
coordinates of the camera with respect to the field. Afterwards, the following nine lines contain
information about each of the robots, and the ball. Each of these lines contains the following
information:
• Object type: ball, robot, etc.
• Object name: “ball” for the ball, and an identifier for each robot.
• Whether the object was found by the video server or not. In case it wasn’t found, the
server will predict the information for this frame.
• The (x, y, z) coordinates of the object.
• The object’s orientation, in radians.
• The object’s velocity with respect to the x and y directions.
This information is then processed by each of the two teams’ agents (see Figure 1), which will
be running on computers which we will call PC Shuttles (one for each team). Communication
follows a client/server model. Therefore, the agents are clients which receive the video server’s
packages by means of the league’s local network. In Figure 1, this can be seen in the connection
from Doraemon to PC Shuttle. This completes the “vision path”, which carries perceptual
information from the environment to the agents.
Figure 1: E-League setup
Figure 2: A proposed architecture for the implementation of an E-League team.
The “effectoric path” also responds to a client/server model, in which the teams are clients
of the Command Server. At every time step, the Command Server gathers commands from
each of the teams which are sent to the robots on the field. The teams send commands of
the form “[name]:[msg]\n”, where name is the robot’s name, and msg is the message sent to
it. The Command Server has a command buffer for each robot, which is updated as messages
arrive. Periodically, the Command Server will send these messages to the robots by means of
one or more infra-red transmitters directed towards the field. Each robot is capable of receiving
these messages, and obtaining the command that is directed to him.
3 Architecture for Team Implementation
We are currently working on the implementation of a team for competing in Robocup E-League
2004 [3]. The organization of this implementation is being carried out in layers, each of which
offers support at a given level of abstraction. The objective of this model is to modularize
the solution to this problem, isolating the different aspects that must be solved by means of
these layers. For instance, the problem of communicating with the vision server should not be
intertwined with the task of reasoning about the best strategy for scoring a goal.
In the following, we will describe our approach to this separation into layers (see Figure 2):
• Low Level Communication Layer: This layer contains the low level communica-
tion support provided by the league. This includes infra-red transmitters, video camera,
network support, and the software that is necessary for processing visual information
(Doraemon) and processing commands that will be sent to the field (Command Server).
• Logical Communication Layer: Composed by a set of routines that interface the Low
Level Communication Layer with the higher layers. They provide the necessary services
that enable communication with the servers.
• Sensorial/Efectorial Layer (SEL): In this layer, raw visual information is processed
and translated into environment states that reflect a higher level of abstraction. For
example, given a set of coordinates and speed for each of the robots and the ball, this
information could be translated into “robot r3 is in position to kick the ball”. Another
function implemented by this layer involves the translation of actions selected by the
agents into packets that will be sent to the Command Server.
• Cognitive Layer: This layer models the behavior of the team of robots. It contains
the implementation of the agents that represent the team. These agents perceive the
environment only through the information offered by the SEL. Different alternatives are
possible in this layer. For example, one of the choices involves implementing the team as a
society of agents, or as a single agent that controls all of the robots. In the case of a multi-
agent model, decisions concerning communication among the agents must be made (direct
communication through messages, blackboards, multi-agent cooperation protocols, etc).
3.1 Robotic Equipment
Our team is composed of four robots, built with Lego MindstormsTM [5]. The league only
imposes restrictions on processor speed and memory size, and this robotic kit falls within these
restrictions with a speed of 10MHz and 32KB of RAM. This equipment can be loaded with a
variety of firmwares, which determine the programming language that can be used. In this case,
we will use BrickOS [2] and the C programmig language for the program that will be running
on the robots’ processors. This should not be mistaken with the programs that correspond to
the agents, as we will see in the following section.
3.2 Implementation of the Cognitive Layer
The implementation of the Cognitive Layer is currently under development, and it is composed
by logic-based agents that will be implemented using Prolog. This approach has a series of
advantages, such as declarative programming, which allows a more or less direct translation
from behavior models to the code that will be directly executed by the agents.
In this proposal, each agent is implemented by a Prolog program. Based on the environment
information provided by the SEL, these agents will reason and select the next action that will
be executed. This decision is communicated to the SEL, which will build a packet that will be
received by the Command Server via the Logical Communication Layer. Finally, the Command
Server will gather these packets and sends them to the robots on the field.
Another design issue that must be resolved is the basic set of actions that will be available to
the agents in order to carry out their plans. An important aspect of this decision is the tradeoff
between the length of a given basic action and its reliability. That is, a long basic action avoids
excessive sensing and deliberation, but is more prone to failure (for example, due to slipping,
collision, etc). Therefore, we need to decide which actions will be directly implemented in the
robots’ code (which will be activated by messages), and which actions are left as decisions to
be made by the agents as part of their plans.
4 Conclusions
In this work, we have described a proposal for the implementation of a team of robots that will
be participating in the RoboCup E-League competition. We regard this as an opportunity to
build a multi-agent system in which new research ideas and developments can be tested, such as
planning, knowledge representation, argumentation, and multi-agent cooperation mechanisms.
Acknowledgements
We are very grateful to the Association of Computing Machinery (ACM) for granting us a
scholarship that will allow us to cover most of the costs of participating this year in the com-
petition in Lisbon, and to Dr. Elizabeth Sklar of the University of Columbia in New York,
for making this possible. We are also grateful to the Department of Computer Science and
Engineering, Universidad Nacional del Sur, for making its space and resources available to us
at any time. The project is also partially supported by the Agencia Nacional de Promocio´n
Cient´ıfica y Tecnolo´gica (PICT 13096).
Finally, Gerardo Simari is partially supported by Comisio´n de Investigaciones Cient´ıficas,
(CIC) Gobierno de la Provincia de Buenos Aires. Telma Delladio is partially supported by
Consejo Nacional de Investigaciones Cient´ıficas y Te´cnicas (CONICET).
References
[1] http://agents.cs.columbia.edu/eleague/.
[2] http://brickos.sourceforge.net/.
[3] http://cs.uns.edu.ar/∼gis/robocup-tdp.htm.
[4] http://sourceforge.net/projects/robocup-video.
[5] http://www.legomindstorms.com.
[6] http://www.robocup2004.pt.
[7] http://www.robocup.org.
[8] Anderson, J., Baltes, J., Livingston, D., and Sklar, E. Toward an undergraduate league
for robocup. In Proceedings of the RoboCup Symposium (2003).


http://sedici.unlp.edu.ar/bitstream/handle/10915/21247/Documento_completo.pdf?sequence=1

Cognitive robotics in a soccer game domain: a proposal for the e-league competition

Abstract

Similar works

Full text

Available Versions

Servicio de Difusión de la Creación Intelectual

SEDICI - Repositorio de la UNLP