The OpenRDK framework:The OpenRDK framework:a not-so-short tutorial a not-so-short tutorial

Part 2: advanced topicsPart 2: advanced topics

Daniele Calisi, Andrea Censi

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In a multithreaded application, all accesses to shared data must be “protected” with a mutex

Concurrent access management: locksConcurrent access management: locks

Thread 1…;…;…;lock(a);a.something();…;…;unlock(a);…;…;

Thread 2…;…;…;…;lock(A);…;a.something();…;unlock(A);…;…;

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Concurrent memory access: the session objectConcurrent memory access: the session object

RAgent

Module ModuleModule Module

Repository

session session session session

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OpenRDK provides implicit locks/unlocks…

…and explicit locks/unlocks (e.g., large objects)

Concurrent access management: locksConcurrent access management: locks

double a = session->getDouble(…)

lock()get valueunlock()return value

session->lock(A)myObject = session->getObject(A)myObject.function1();myObject.function2();session->unlock(A)

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The The sessionsession object object

Similar to DBMS sessions Recover locked properties

Repository and ModuleManager communication e.g. session->wait() URL context (e.g., “/robot/”) Caching of property names Starting and ending a session collect statistics (e.g.,

iteration duration, time between two start, etc.) Sessions and threads

Mutex (lock/unlock) clean management One session for each thread (you can create other

sessions for your own threads)

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Module codeModule code

class TemplateModule {public: TemplateModule(); virtual ~TemplateModule();

bool initConfigurationProperties(); // bool initInterfaceProperties(); bool init(); void exec(); // void exitRequested(); // void cleanup(); // void asyncAgentCmd(cstr cmd);};

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#define PROPERTY_ALPHA “in/alpha”#define PROPERTY_BETA “in/beta”#define PROPERTY_RESULT “out/result”#define PROPERTY_MY_MAP “out/myMap”

bool MyModule::initConfigurationProperties(){ SESSION_TRY_START(session) // ... session->createDouble(PROPERTY_ALPHA, "Alpha", RDouble::SEC, 10.); session->createDouble(PROPERTY_BETA, "Beta", RDouble::RAD, deg2rad(20.)); session->createDouble(PROPERTY_RESULT, “Result", RDouble::M, 100.); session->createMap(PROPERTY_MY_MAP, “The map", 1., 2., 0., 10., 20, 20); SESSION_END(session) return true; SESSION_CATCH_TERMINATE(session) return false;}

initConfigurationProperties()initConfigurationProperties()

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bool MyModule::init(){ SESSION_TRY_START(session) // open sockets... // connect to hardware... session->listenToTimer(500.); SESSION_END(session) return true; SESSION_CATCH_TERMINATE(session) return false;}

Can listen to: timers property changes nothing (non-OpenRDK entities: sockets, drivers, ...)

init()init()

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void MyModule::exec(){ while (session->wait(), !exiting) { SESSION_TRY_START(session)

double alpha = session->getDouble(PROPERTY_ALPHA); double beta = session->getDouble(PROPERTY_BETA); double gamma = alpha * beta; session->setDouble(PROPERTY_RESULT, gamma);

session->lock(PROPERTY_MY_MAP, HERE); RMapImage* m = session->getObjectAsL<RMapImage>(PROPERTY_MY_MAP); m->setPixelB(0, 0, RImage::C8Red); session->unlock(PROPERTY_MY_MAP);

SESSION_END_CATCH_TERMINATE(session) }}

exec()exec()

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Under the hood: startup order Under the hood: startup order

module1

module2

module3

>> Load configuration file <<

>> Instantiate modules <<

module1.initConfigurationProperties()module2.initConfigurationProperties()module3.initConfigurationProperties()

>> Configure properties (1) <<

module1.initInterfaceProperties()module2.initInterfaceProperties()module3.initInterfaceProperties()

>> Configure properties (2) <<

module1.init()module2.init()module3.init()

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Under the hood: execution and terminationUnder the hood: execution and termination

module1

module2

module3

module1.init()module2.init()module3.init()

>> Multithreading starts <<

module2.exec()module1.exec() module3.exec()

module1.exitRequested()module2.exitRequested()module3.exitRequested()

>> Multithreading ends <<

module1.cleanup()module2.cleanup()module3.cleanup()

>> Agent terminated <<

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Queues as object dispatchersQueues as object dispatchers Producer/consumer problem; FIFO

Addressed like other properties (URL)

Features multiple consumers (concurrently)

no object duplication

automatic garbage collection

filters

passive

Can be used for localization (e.g., laser)

logging

Module

Queue

ModuleModule

QueueQueue

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The The SimpleTcpInterfaceModuleSimpleTcpInterfaceModule

Text-based interactionExternal applicationTELNET

> propertyList/robot/enabled/robot/odometryPose/localizer/estimatedPose

> getValue /robot/enabledYes

> getValue /robot/estimatedPose10.4 32.12 45°

> setValue /robot/enabled No

> getValue /robot/enabledNo

Example:

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Connection to RT systemsConnection to RT systems

RT-Process

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The build systemThe build system

$ cd TheDirectoryOfMyModules$ rdk-create-module-dir.sh –m MyNewModule$ lsmynewmodule$ ls mynewmoduleCMakeLists.txt mynewmodule.h mynewmodule.cpp mynewmodule_names.h$ cd mynewmodule$ cat CMakeLists.txtRDK_ADD_RAGENT_MODULE(ALL_FILES)$

…$ cat CMakeLists.txtIF(PALTALIB_FOUND) RDK_ADD_RAGENT_MODULE(ALL_FILES) INCLUDE_DIRECTORIES(${PALTALIB_INCLUDE_DIR}) LINK_DIRECTORIES(${PALTALIB_LINK_DIRECTORIES}) TARGET_LINK_LIBRARIES(${RDK_THIS_MODULE_NAME} ${PALTALIB_LIBRARIES})ENDIF(PALTALIB_FOUND)$

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OpenRDK current applicationsOpenRDK current applications Rescue wheeled robots (real robots, USARSim)

RoboCare project (assistive robots for the elders)

Quadrotor, tarantula (real robots, USARSim)

RoboCup Standard Platform League (“Nao league”)

HRI experiments (robot side)

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SummarySummary OpenRDK features

Modularity and concurrent engineering Full multi-thread support Blackboard-style communication (properties can be shared among

different processes) Tools (Logging/replaying, RConsole, etc.) Open source (GPL license)

Extend the property sharing mechanism More network QoS (e.g., from DDS: latency budget)

On-line fault detection system Configuration file editing and analysis tools

Graphical on-line configuration editor Detect possible deadlocks Verify constraints on schedule

More connectivity with the rest of the world Scripting (Ruby, Python) support Design a better logo!

On-going and future workOn-going and future work

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QuestionsQuestions

Questions?We are on SourceForge:

http://openrdk.sourceforge.net

Credits:Prof. Daniele Nardi

Developers: Daniele Calisi, Andrea CensiEarly contributors: A. Farinelli, G. Grisetti, L. Iocchi

Current contributors: F. Giannone, L. Iocchi,M. Leonetti, L. Marchetti, D. Nardi, P. de la Puente,

G. Randelli, M. Sbarigia, A. Valero, R. Vicario