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> Open Source Real Time Option for Dymola
Jawhar
post Apr 28 2008, 08:20 AM
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Hello wagner,

I mean by "more little time steps" the sampling time.

CODE
    //create event to update simulation speed reference point in time
    s:=sample(0, samplingTime);


can we say that if we decrease samplingtime the simulation is more precise?

Regards,
Jawhar


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wagner
post Apr 28 2008, 07:39 AM
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Hello Jawhar,

I don't get your points.

What do you mean by "more little time steps" and "more real time"?

And what about accelerate the simulation?

In general, the covered real time problems arise when you use an integration method with variable step size (like Dassl) where simulation speed varies (due to varying step size).

Regards

Florian
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Jawhar
post Apr 28 2008, 07:20 AM
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QUOTE(Jawhar @ Mar 7 2008, 10:32 AM) *

Hello Wagner,

Ok for the english abstract, i haven't see it. Can i put the web adress of the forum in my thesis as reference? It will be a free advertising for the modelica forum biggrin.gif

I will inform you when i port the code and test it under OpenModelica and linux. It's a good idea to put this work on the Modelica homepage.

Regards,
Jawhar


I am back.. I lost time working with another simulator wacko.gif

I have a remark: can we say that using a more little time step make our simulation "more real time"? if true, we will have a time lost for computation (many time steps) unsure.gif

Is there a method to accelerate the simulation? (i think the answer is no, we had to use more calculators or somethinng like that).


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Jawhar
post Mar 7 2008, 10:32 AM
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QUOTE(wagner @ Mar 6 2008, 09:12 PM) *

Hello Jawhar,

unfortunately we don't have an english version of the paper, but the german paper has an english abstract ;-) .
But I see, I should write a technical report in English to fix this mistake.

When you port the library to linux and OpenModelica it would be quite nice if we merged things together and put it on the Modelica homepage.

Regards

Florian


Hello Wagner,

Ok for the english abstract, i haven't see it. Can i put the web adress of the forum in my thesis as reference? It will be a free advertising for the modelica forum biggrin.gif

I will inform you when i port the code and test it under OpenModelica and linux. It's a good idea to put this work on the Modelica homepage.

Regards,
Jawhar


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wagner
post Mar 6 2008, 08:12 PM
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Hello Jawhar,

unfortunately we don't have an english version of the paper, but the german paper has an english abstract ;-) .

QUOTE
Testing is an integral part of modern controller development. Hardware-in-the-Loop (HIL) simulation plays a prominent role as test method. In HIL, the implemented controller is tested against a computer model of the process. Besides the communication between simulation and controller, HIL requires their synchronization. However, in long simulations of complex models exact synchronization over time is hard to guarantee. The paper investigates the im-pact of a temporarily too slow simulation on the test. As a result, a new synchronisation ap-proach is presented and applied (in the simulator Dymola) to an industrial example.


But I see, I should write a technical report in English to fix this mistake.

When you port the library to linux and OpenModelica it would be quite nice if we merged things together and put it on the Modelica homepage.

Regards

Florian
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Jawhar
post Mar 6 2008, 06:45 PM
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Hello wagner,

I hope that you are fine.

I tested your realtime library, it's working.. I tried to download the paper but it's in german langage unsure.gif
Have you an english version? If i had to use this option i had to make your paper as reference in my thesis smile.gif

I will try the next week to port your code into Linux but under OpenModelica. I wil tell you if it will work fine or not!

Thank you for sharing your idea!

Best regards,

Jawhar


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wagner
post Jun 6 2007, 04:04 PM
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Hello,

I created an open source (and thus free of charge) real time option for Dymola called JPAARealTime. It can be used as replacement for the "Synchronize with realtime" feature in Dymola. Maybe some Dymola users might be interested in it.

JPAARealTime is a Modelica Model which can be inserted in Modelica other models which are then synchronized with real time. It provides the same features like the Dymola realtime feature. Additionally simulation speed can be limited. This feature is quite usefull in hardware in the loop simulations.

If the simulation of the process got stuck for while (probably due to a lot of events) the lost simulation time (compared to realtime) is regained as fast as possible by simulating as fast as possible. This can lead to unpredictable behaviour in the externally attached controller since simulated signals are changing extremly fast in the regain-phase. By limiting simulation speed this behaviour can be avoided.

JPAARealTime can also be used with Library UserInteraction 0.52 which allows manual interference with the simulated model during simulation time.

Since JPAARealTime makes use of Windows libraries it can only be run on Windows operating system. Maybe there'll be Linux support in future versions.

Currently JPAARealTime cannot be used with DDE Compiler option enabled.

The newest version of JPAARealTime is available on http://www.eit.uni-kl.de/frey.

To use JPAARealTime copy JPAARealTime.mo, TimerAccess.h and TimerAccesLibrary.lib to the directory of the model you want to simulate.

Error reports and user feedback are quite welcome.


Regards

Florian
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