Simulink disc rotation

[JPGraphX]

Hi!

I want to simulate the reaction of a rotating disc with 2 spring in simulink. On my picture, you can see a disk rotating over a shaft. My disc has 2 spring attached to the shaft. They slow my rotation.

http://s21.postimg.org/9q3z9yvbr/forum.png

Here is how it work: You turn the disk (90 degrees) and release it, then it oscillate until it completely stops.

I would like to do a simulink with a response like my chart(graphic) on the picture. I need to enter my spring k constant and somewhere to enter friction of bearing (that friction factor is going to be the one to help me align reality and theory).

Thanks a lot for your help, I know this is a really simple simulink, but it's been a lot of time since my last use of simulink!!

Jean-Philippe

 

[FeX32]

Do you want to conduct a simulation based on the systems differential equation? Or via Simulink's mechanical modeling blocks?

If you want to simulate it by solving the differential equation you can do so using ode45 in Matlab. You don't even need Simulink.
However, this can also be done in Simulink too.
The general differential equation for the system you describe is:

theta(t)_dd+k*theta(t)=0



"Simplicity is the ultimate sophistication." L. da Vinci
G. Coppola

 

[JPGraphX]

Hi!

Thanks for you answer, but i would like to solve it with Simulink's mechanical modeling blocks.

Can you help me do that ?

Thanks,
JP

 

[FeX32]

I felt like solving it using ode45.
Here it is:

http://goo.gl/CMYscT

Complete with a quick picture and the 2 .m files. Run ode_disc.m
If you need to solve it in simulink let me know.

Cheers,


"Simplicity is the ultimate sophistication." L. da Vinci
G. Coppola

 

[JPGraphX]

Yeah I need a simulink, is it possible?

Thanks very much!!!
JP

 

[JPGraphX]

I'm not sure if I explain clearly my situation.

It is a disc rotating around a shaft, and the deceleration is due to 2 "rubberband" fix from the shaft to the disc.

When I move the disc 90 degree and release it, my rubberband angle change.

JP

 

[FeX32]

If I understand you correctly, the "rubber bands" can just be interpreted as a stiffness. You can use the model I gave above or slightly modify it.
Attached is a crude sketch I drew to show you how to model it in Simulink. (not using simscape as it's not useful in this case)


"Simplicity is the ultimate sophistication." L. da Vinci
G. Coppola

 

[JPGraphX]

This is my setup:

http://s21.postimg.org/9q3z9yvbr/forum.png

 

[FeX32]

From that picture all I can gather is that the bands act as a torsional stiffness component.


"Simplicity is the ultimate sophistication." L. da Vinci
G. Coppola

 

[JPGraphX]

Sorry, wrong picture:

http://s14.postimg.org/4qyp03uw1/sandbox_model2.png

(TOP VIEW)

 

[JPGraphX]

This is the application:

http://www.youtube.com/watch?v=jgIRu39fH18

I need to simulate that disc movement on simulink.

 

[FeX32]

That's pretty cool. Never heard of a "sandbox".

I hope you understand that what I gave you is a good start to modeling that. Start with the Simulink diagram I gave you (which is equivalent to the .m codes)
Then if you really want to use simscape/simmechanics for visualization I suggest you look into simmechanics link. This will allow you to import your CAD assembly (complete with motion constraints) into Simulink/simmechanics for simulation.


"Simplicity is the ultimate sophistication." L. da Vinci
G. Coppola

 

[FeX32]

Think of the rubber bands as a rod with very large compliance. The dynamic model is the same (neglecting the inertia of the rod)


"Simplicity is the ultimate sophistication." L. da Vinci
G. Coppola