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Trouble solving pendulum model

#3077  Permalink Top

Trouble solving pendulum model

Jan-18-13 13:54:43

Hello,

I am trying to simulate the pendulum model in the user guide (release 1.9.0 beta), and am encountering the following issue:

Code:

record SimulationResult

    resultFile = "C:/DOCUME~1/ajpm/LOCALS~1/Temp/OpenModelica/MyPendulum3D_res.mat",

    simulationOptions = "startTime = 0.0, stopTime = 5.0, numberOfIntervals = 500, tolerance = 1e-06, method = 'dassl', fileNamePrefix = 'MyPendulum3D', storeInTemp = false, noClean = false, options = '', outputFormat = 'mat', variableFilter = '.*', measureTime = false, cflags = '', simflags = ''",

    messages = "warning | Error solving nonlinear system residualFunc2 (size 1) at time 1.3237

warning | Error solving nonlinear system residualFunc2 (size 1) at time 1.32375

warning | Error solving nonlinear system residualFunc2 (size 1) at time 1.32373

warning | Error solving nonlinear system residualFunc2 (size 1) at time 1.32373

etc...

The model itself is as per the user guide:

Code:

class MyPendulum3D "Planar Pendulum"

constant Real PI=3.141592653589793;

parameter Real m=1, g=9.81, L=5;

Real F;

Real x(start=5),y(start=0);

Real vx,vy;

equation

m*der(vx)=-(x/L)*F;

m*der(vy)=-(y/L)*F-m*g;

der(x)=vx;

der(y)=vy;

x^2+y^2=L^2;

end MyPendulum3D;

If I then try to add the 3D visulisation, it crashes in a similar manner to the one described in https://www.openmodelica.org/index.php/ … pic?id=817, even when changing the location of the SimpleVisual.PositionSize type commands to be just before the equation section.

Any suggestions?

Thanks,

Arnaud

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