Proceedings of the 10th Mediterranean Conference on Control and Automation - MED2002 Lisbon, Portugal, July 9-12, 2002This paper describes the design and implementation
status of the ISePorto robotic football team for
participation in Robocup Middle Size League (F2000).
The objectives guiding the project were the
applications and research in hybrid control and
coordination systems. The system has also an
educational support role. A special attention is made to
the custom design to allow the execution of complex
manoeuvres and team coordinated behaviours. The
robot has different pass, shot, and manoeuvre
capabilities providing high level tactical and strategic
planing and coordination. The current team status is
also covered

Almeida, José

Baptista, João Paulo

Martins, Alfredo

Silva, Eduardo

Repositório Científico do Instituto Politécnico do Porto

See	discussions,	stats,	and	author	profiles	for	this	publication	at:	http://www.researchgate.net/publication/228643028Design	of	the	ISePorto	Robocup	Middle-SizeLeague	Robotic	Soccer	Team:	Control,Localisation	and	CoordinationARTICLECITATIONS3READS664	AUTHORS,	INCLUDING:Alfredo	MartinsInstitute	for	Systems	and	Computer	Engine…50	PUBLICATIONS			240	CITATIONS			SEE	PROFILEJ.M.	AlmeidaInstituto	Superior	de	Engenharia	do	Porto46	PUBLICATIONS			153	CITATIONS			SEE	PROFILEE.	Pereira	SilvaInstituto	Superior	de	Engenharia	do	Porto62	PUBLICATIONS			199	CITATIONS			SEE	PROFILEAvailable	from:	E.	Pereira	SilvaRetrieved	on:	23	October	2015 Design of the ISePorto Robocup Middle-Size League RoboticSoccer Team: Control, Localisation and CoordinationA. Martins*, J. Almeida*, E. Silva, J. P. Baptista*Instituto Superior de Engenharia do PortoRua de S. Tomé 4200 Porto, Portugale-mail: {amartins,jma,eaps,jpaulo}@dee.isep.ipp.pt,†MED2002 Conference e-mail: med2002@isr.ist.utl.pthttp://www.isr.ist.utl.pt/med2002Keywords: control applications, robocup, roboticsoccer, mobile robotics, vehicle control.AbstractThis paper describes the design and implementationstatus of the ISePorto robotic football team forparticipation in Robocup Middle Size League (F2000).The objectives guiding the project were theapplications and research in hybrid control andcoordination systems. The system has also aneducational support role. A special attention is made tothe custom design to allow the execution of complexmanoeuvres and team coordinated behaviours. Therobot has different pass, shot, and manoeuvrecapabilities providing high level tactical and strategicplaning and coordination. The current team status isalso covered.1 IntroductionThe ISEP Autonomous Systems Lab. (LSA) roboticfootball team provides an excellent tool to develop anddemonstrate the research in the areas of interestassociated with autonomous systems. These are mainlysensor fusion, mobile robotics navigation, nonlinearhybrid feedback control and coordination. Additionallyto the research interests, the laboratory has a strongeducational purpose, being the robot team a goodsupport to curricular and extra-curricular work in theareas of mechatronics, electronics and embeddedsystems.The remaining of the paper overviews the robot design,the control and navigation issues, coordination andstrategy guidelines finishing with the current team status.2 Robot DesignThe team robot was designed and implemented fromscratch in order to be a suitable testbed for advancedmultirobot coordinated control. The mechanical designhas taken in account the requirements to executecomplex manoeuvres and therefore not posing harshlimits on the control, navigation, or coordinationdevelopments.The robot is constituted by three parts: a circularmobile base, a kicker connected to a structure thatrotates around a central vertical axle and on top acomputational an electronics module fixed relatively tothe base with a pan mounted camera. The system ismechanically modular; it can be used in differentconfigurations, such as different kicker designs with thesame base. The base contains two differential traction24 V DC motors with optical encoders for motorcontrol and vehicle odometry, two 12V lead acidProceedings of the 10th Mediterranean Conferenceon Control and Automation - MED2002Lisbon, Portugal, July 9-12, 2002.batteries, the kicker rotation motor and the motorpower drives. The kicker uses a DC motor andmechanical spring with a camber and was designed toallow different kick strengths ranging from small passesto goal shots. This, coupled with the rotation allows therobot to perform complex manoeuvres.The main computational system is consists of a 5.25”SBC (ICP NOVA600 with an AMD K6-2 300MHzor ICP NOVA7896FW with a 900Mhz Celeron) andIDE 24Mb Flash disk. Each robot communicates withthe team and the host visualisation computer by anethernet wireless modem (OTC AirEsy2405 at 2.4GHz), to be changed to new modems compliant withIEEE 802.11.The motor control is made in a custom designed multi-axis control board, comprising a FPGA (FLEX10K10) and dedicated microcontroller (T89RD2). Itcommunicates with the main CPU trough a PC104connector (ISA bus). The PC104 form factor reducessize and it is a reliable connection system. The boardimplements 4 axis PID control at 2 KHz (traction,kicker rotation and shot), receiving encoder informationand providing a sign magnitude PWM control signal tothe power drives. Additionally, this board interface amagnetic compass (Vector 2X), and an optical switchto calibrate the angle of the rotating kicker with respectto the robot base.The onboard computer runs a Linux operating from theflash disk, with a modular and hierarchic threadedsoftware architecture [3], [4].3 Vision SystemThe vision system uses two USB cameras (PhilipsPVC740K with a new wide angular lens from MarshallElectronics optics). One mounted on a central pan unitand used mainly for long range vision and localisationand the other fixed to the kicker to be used for fine ballcontrol.Device DriverVideo4LinuxColor classificationObject detectionHardware(USB, camera)Sensor ManagerRequest  Vision dataOperating System (Linux) Hardware Vision SystemFigure 1 -  Vision system architectureThe main characteristic of our vision system is theability to perform a fast global analysis of the all imagein order to decide where to conduct a more detailedone. An additional improvement is accomplished withthe integration of the prediction the landmarks in thegrabbed image or where the camera should point.Additionally the robot has a custom developed ring ofIR range measuring sensors for short distance obstacledetection (up to 0.8m) and a magnetic compass.4 LocalisationIn the Robocup to achieve good team play capabilities,is required a good robot localisation and control.Besides the robot self-localisation it is also necessary toperform adequate ball (and if possible other players)localisation.The ball position estimation uses a Kalman filter tankingin account the robot model and the informationreceived from the vision system. Adaptive balldetection algorithms are used for different cases of ballposition and occultation in the image.Figure 2 - Different ball position and partial view withinthe image frame.An updated ball position estimate is maintained in therobot internal state.BallDetectionXball  ref.cameratoXball  ref. robotBall stateestimationballPballXrobotProbotX,ˆ,ˆXball ref. cameraXball ref. robot (timage)worldinfoballball PX ,ˆimageFigure 3 - Ball localisation process.The self-localisation is mainly done by the fusion ofvision measures of world landmarks (goals, corner andground marks), internal sensors (odometric andmagnetic compass) and external vision measures, usingKalman filtering methods. We plan to test fusionalgorithms based in covariance intersection [6].Furthermore, each robot have a world state with someknowledge of position, attitude and his derivatives, withsome uncertainty measure for all the game movingobjects. This is accomplished with distributed sensorfusion, where the vision sensors play a key role insensing. Also, a distributed dynamic camera allocationand managing is under study.In the presence of communications problems, thedesired information must be perceived individually byeach player. In the last case, in spite of an obviousdegradation of the world model, some teamcoordination must be accomplished by the perceivedinformation of our robots.5 ControlThe motion control architecture approach [1] is basedin atomic parameterised hybrid feedback controller,also known as manoeuvre. These controllersincorporate both continuous and event drivenfeedback. This approach involves the atomicparameterised hybrid controllers synthesis. A set ofmanoeuvres solving specific classes of motion problemsis defined and implemented. These are classifiedaccording to the patterns of the associated constraintsand objectives. Those manoeuvres are the resources tothe coordination level. The sets of manoeuvres that arebeing synthesised are:Motion without ball:- Move to location avoiding obstacles- Block goal path- Approach ball with defined attitude- Move to maximise target vision information- Goalkeeper block goal pathCoordinated robot and kicker motion:- Smooth ball receptionBall guidance:- With robot rotation around ball centre- Straight line- Curve- With directional shoot and defined strength- Interception and kick- Lateral pass with kicker rotationFigure 4 - Robot photoIn the following figure overall control systemarchitecture is presented.HLow level motion controlVision SystemH H HHSensors boardVector2XIrodometryKicker SystemMotion SystemManoeuvre Control Game Status Identification Strategy CoordinatorSelflocalisationBalllocalisationOther robotslocalisationcompassFigure 5 - Robot subsystems6 Coordination StrategyThe team game evolution is coordinated in structuralway [2], [5], by defining the tactical function (goalkeeper; defence; middle field; attack) for each robot.The robot adopts the corresponding tactical policyaccordingly to its perception about the companions inthe field. The player has one main place in the overallstrategy (as consequence of its tactical position), butthis can be reconfigured dynamically. Only one robothas the possibility to adopt the goal keeper position.The overall strategy solution results from thecomposition of the decisions taken in a distributed wayby the operational robots in the field. The analysis ofthe vectors: game phase, ball possession and currenttopology formation in conjunction with the currentrobot game role and its perceived topological positiondetermines the coordination level for each robot. Anevaluation of the next action to be taken is made by themaximisation of hypothesis success.The coordination level is implemented by a modularand distributed controller synthesis trough thecomposition of discrete observers (corresponding tothe analysis vectors) and a discrete controllerparameterised by the adopted tactical functionality7 Current Team StatusWe have a full team plus a spare robot ready. We havestable versions of the axis control, motors powerdrives, compass, kicker control, power distribution,and power monitoring boards. The old NOVA-600SBC are being replaced by the new NOVA-7896FWboards, and a new IR range finder ring is in final tests.Figure 7 - Team photo8 Conclusions and Future WorkThe robotic soccer team ISePorto design is presented.This complex mobile robotics is a motivating exampleto the research and development of control andnavigation. The control and navigation architecture forthe robots is described.This hierarchic architecture entails the use of hybridcontrol automata in order to achieve complexbehaviours.The coordination and game strategy issues are alsoreferred.The team status is still at an initial development stage,with a vast number of areas to be developed. In thesewe could name the other players localisation, gamestatus observer development, team topologicalformation classifier, additional control manoeuvres andgame control/API software development.AcknowledgementsThe authors would like to thank the LSA team for theirefforts and dedication in developing the robots andsupport on the participation of competitions and events.References[1] J. M. Almeida, F. L. Pereira, J. B. Sousa, “AHybrid Feedback Control System for aNonholonomic Car-like Vehicle” IEEEInternational Conference on Robotics andAutomation, Albuquerque, New Mexico, (1997)[2] E. P.Silva, F. L. Pereira and J. B. Sousa, “On theDesign of a Control Architecture for anAutonomous Mobile Robot”, chap. 15, inAdvances In Intelligent Autonomous Systems,ed. S.G. Tzafestas, Kluwer Academic Publishers,(1999).[3] E. P. Silva, J. M. Almeida, A. Martins, et al,"Multi-task Real-Time environment for anautonomous mobile platform", PO-ROBOTProject Final Report, (1999).[4] J. M. Almeida, E. P. Silva, A. Martins, et al,"Functional Layer of the control architecture PO-ROBOT Project Final Report, (1999).[5] E. P. Silva, F. L. Pereira, J. M. Almeida,"Coordination and Organisation layer", PO-ROBOT Project Final Report, (1999).[6] Covariance Intersection Working Group (CIWG),"A Culminating Advance in the Theory andPractice of Data Fusion, Filtering, andDecentralised Estimation".[7] Jose Almeida, Alfredo Martins, "Designing aMiddle Size League Team - The ISePorto Case",in RoboSoccer Tutorial - 10th EPIA, (2001)

Design of the ISePorto robocup Middle-Size League Robotic Soccer Team: Control, Localisation and Coordination

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Design of the ISePorto robocup Middle-Size League Robotic Soccer Team: Control, Localisation and Coordination

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