© 2009 IBM Corporation Verification of embedded system specifications using collaborative simulation of SysML and Simulink models Ryo Kawahara*, Hiroaki Nakamura*, Dolev Dotan**, Andrei Kirshin**, Takashi Sakairi*, Shinichi Hirose*, Kohichi Ono*, Hiroshi Ishikawa* *Tokyo Research Laboratory, IBM Research **Haifa Research Laboratory, IBM Research

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation Abstract  The authors propose an extension of SysML which enables description of continuous-time behavior.  The authors also develop its execution tool integrated on Eclipse-based platform by exploiting co-simulation of SysML and MATLAB / Simulink.  To demonstrate the effectiveness of the tool and the extension to SysML in verifying specifications of an embedded system, we create a sample model and analyze its execution results by checking constraints under a test case.

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation Introduction  In the development of an embedded system, it is important to verify that the specification of the system satisfies the requirements at an early stage –One approach to achieve this is to model and simulate the system during the analysis –Systems Modeling Language (SysML) is an extension of UML for embedded systems to include heterogeneous elements such as software, electronics, or mechanics

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation Subject  Embedded systems often include control systems –A control system is usually a hybrid system, the mixture of continuous-time and discrete behavior –Continuous-time behavior in UML / SysML has not been defined –Simulation of control system is usually done in a specialized tools, such as the MathWorks MATLAB / Simulink –A UML / SysML behavior is not associated with time  Integration of the continuous-time behavior into the systems model is desired

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation Background: SysML  SysML is an extension of UML2 for systems engineering  Requirements –Requirement diagram  Behaviors –Activity diagram –State machine diagram  Structures –Block definition diagram => class diagram –Internal block diagram => composite structure diagram  Parametrics –Parametric diagram => internal block diagram

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation Background: Simulink  Simulink uses Block diagram –Block diagram describes the flow of signal between blocks, which process the signal –This example calculates:

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation Approach  Use SysML for a system architecture description  Use specific languages for each domain –Simulink for continuous-time behavior in a control system  Time duration assignment to SysML action  Verify specification by collaborative simulation –Run multiple simulation in parallel with time synchronization –Independent time management module

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation Extended Modeling for Simulation in SysML Time assignment to action Continuous data exchange between blocks Specifying Simulink model as a block behavior MARTE > stereotype, or sleep() method in action code SysML flow ports with connectors in internal block diagram > stereotype to specify model file

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation SysML Execution and Debugging  Debugging of behavioral UML models by emulation, supporting: -Class, Composite Structure Diagrams -State Machines, Activities -Java as Action Language  Extensible to support UML profiles (in this case SysML)  Debugging UI – Model Debugging Perspective (next slide)  Diagram animation  Debugging modes:  Traditional Debugging -Start “main” -Run to breakpoint -Stepping  Interactive debugging (model “exerciser”) -Manually create objects -Invoke operations -Send signals Current State Execution Pending Running Transition Breakpoint

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation Model Debugging Perspective Debug Variables Console Diagram Animation Signals Event Pools Instances Breakpoints I/O Snippet Watch Sleeping

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation Sleeping View Shows the queue of sleeping behaviors and behavior elements. Wakeup time Current virtual time

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation Time Management  Data is exchanged and the next Simulink step is executed at: –End of timed SysML behavioral step ( > or sleep() ) –Periodic data exchange event SysML object MATLAB / Simulink Timed scheduler UML execution engine Time management module Demands of time Add periodic data exchange events into the list consists of the discrete events Time demands to scheduler MATLAB / Simulink command execution … Simulation start / stop SysML object 400 Time Periodic data exchange events Discrete events Action1 Action2 Action3

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation Co-simulation with Simulink  All the Simulink models are referred from a single temporary Simulink model –Only one Simulink process is used  Simulation data is sent or received through Input/Output S-Functions Model reference1 Input S-Function Model reference2 Output S-Function Temporary generated Simulink model Model 1Model 2 Simulink models which are assigned to SysML behaviors Data from SysMLData to SysML

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation Overview of Sample model: Humidifier  Requirements –The humidifier starts vapor emission within 5 minutes since the power on signal –The humidifier ends cool down within 10 minutes since the power off signal –The humidifier keeps the room humidity at a constant level specified by the user automatically Heater Reservoir Circulator fan Pan  Basic mechanism –The water is boiled by the heater –Vapor is emitted to the environment by circulator fan

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation Structure of HumidifierSystem Simulink model assigned block State machine assigned block Block definition diagram Internal block diagram of HumidifierSystem Flow ports for continuous I/O Standard ports for discrete signals Simulink model assigned block State machine assigned block

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation Behavior of Control block State machine diagram Signal from user interface Change event that monitors values from a Simulink blocks

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation Simulink model for VaporGenerationPlant heating subsystem radiation subsystem evaporation subsystem

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation Test context Simulink model assigned block Block definition diagram Internal block diagram of TestContext Flow ports for continuous I/O to consist a closed loop Definition of test environment Test target

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation Cooling down taking too long time Test case and results Time(s)Command 0Test start 10Power on 2000Power off 3600Test end Automatic humidity control

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation Parametric and time constraint evaluation Parametric diagram Sequence diagram with time constraint using MARTE profile Constraint block: Humidity should be kept near target value Timed constraint: Cool down should be finished within 10 minutes

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation Conclusion  We have developed a verification tool based on co-simulation of Simulink and SysML  We have extended the modeling capability of SysML to be able to reference Simulink models and specify timed behavior  These extensions enable one to test specifications of a system which includes continuous-time behavior in a closed control loop

© 2009 IBM Corporation

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation Overview of the verification tool Block2 Integer b = 1 Block3 Integer c = 2 Integer eval eval = f(bb, cc) bbcc eval Eval > 80 eval Virtual time scheduler Time-aware UML execution engine Simulink pq {h,i} pq {j,k}lm {n,o} {a,b,c} |{d,e,(f|g}} Parametric constraint evaluatorTime constraint evaluator Binary tree for fast eval. TPTP-based test driver Timed test casesTimed discrete behaviorContinuous behavior Parametric constraints (OMG SysML) Time constraints (OMG MARTE profile)

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation Simulink model for Room block saturation_vapor_pressure subsystem relative_humidity subsystem

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation State machine diagram of HeaterControl block

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation Related works Reichmann et al. (2004), Telelogic Rhapsody® C. Nytsch-Geusen (2007), A. Pop et al., (2007), T. A. Johnson et al., (2008) Hooman et al. (2004) Our approach Coupling method Conversion to source code Conversion to Modelica Co- simulation of Simulink and Rose® RT Co- simulation Simulation time management By independent module (Rhapsody) By ModelicaBy SimulinkBy independent module Studies on coupling of UML/SysML and continuous-time simulation (e.g., Simulink)

Haifa Research Lab – Model Driven Engineering Technologies Group © 2009 IBM Corporation Related works  Source code level linkage of UML and Simulink –Reichmann et al., Telelogic Rhapsody®  Co-simulation of Simulink and UML model on IBM Rational Rose® RealTime –J. Hooman, N. Mulyar and L. Posta, 2004  Conversion of UML/SysML to Modelica language –C. Nytsch-Geusen, A. Pop et al., T. A. Johnson et al., 2008 –Modelica is a new language to model continuous-time system