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> Peak at change of clutch mode, Peak at torque and acceleration
Henrik
post Jul 25 2008, 05:14 PM
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Normally, I use an interval length of 0.01 and a tolerance of 0.0001. I have tested my simulations with an interval length of 1e-4 and a tolerance of 1e-9, but this doesn't change the result. I get the same peaks described below. I am using the Dassl Solver.

Has somebody any other suggestions, experiences, hints ... ?!

Henrik
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smoss
post Jul 19 2008, 05:52 AM
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Henrik,

In the dymola Simulation->Experiment Setup->General menu, what is your 'Number of Intervals'?

Is it possible these spikes are occuring at every gear shift, however only being recorded every now and then because your Number of Intervals is small?

If you haven't tried it already, increase the Number of Intervals to 5e5, and reduce the Tolerance to 1e-9 and see if the glitches are different?

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Henrik
post Jul 18 2008, 10:26 AM
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Hello,

I'am modelling a vehicle power train with a double clutch transmission with Dymola 6.1 and MSL 2.2. There, I use clutches (Modelica.Mechanics.Rotational.Clutch) for the two clutches and the particular synchronisiers of the gears.

Sometime I get infinite small peaks during simulation at the torque, the derivate of the speed and the vehicle acceleration. These quantities are a function of each others, so if the peak occures, it occures at all these signals at the same time. At the peak I get for one timestep a correct signal value and the peak value.

Here is an example: Attached Image

Does anybody have the same experiences? Do you have a solution or a hint? The occurance of the peaks is not deterministic. If I change parameters or the control bahaviour, the peaks occure sometimes and sometimes not.

The peak occures if a clutch changes from locked to slidding, or vice versa. My modell contains only ideal components yet, is that the reason?

Best regards,

Henrik
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