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Trouble to model friction
Trouble to model friction
Hi everybody,
I'm starting using OpenModelica and I have a question :
I would like to model constant friction for both BearingFriction and LossyGear (in Modelica.Mechanics.Rotational components).
In the documentation, it seems that the friction depend on the velocity (which is a good thing) but I don't have the information for my mechanism.
How can I choose parameters to have a constant friction torque in the bearing friction and to have a constant efficiency in the lossy gear whatever the velocity/speed is ?
Currently, I have this :
BearingFriction, tau pos : [0,0.0003] to have 0.0003N.m
LossyGear, lossTable : [0,0.95,0.95,0,0] to have 95% efficiency in the gear.
For information, the mechanism I'm trying to model is composed of :
spring (it's the driving torque) - bearing friction - inertia (to model a body) - lossy gear - itertia (to model a motor, no driving torque) - bearing friction
All this is using rotational components and the goal is to get the transitional time between initial state (spring compression with a given angle) to the balance (equilibrium) position.
Current result shows a too long transitional time according to measure on a real mechanism. That's why I'm first looking for friction mistake but I may be wrong and made other mistakes in my model.
Thanks for reading, I can share more details if needed.
Re: Trouble to model friction
Hi,
Unfortunately we are not modelers, but compiler developers.
You can try: http://stackoverflow.com/questions/tagged/modelica
as you get far more modelers there.
You could also ask this question on openmodelicainterest@ida.liu.se or openmodelica@ida.liu.se
as you might have a better outcome there.
Cheers,
Adrian Pop/
- adrpo
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