Rotational inertia with spring

[JPGraphX]

Hi,

I would like to calculate the function of a rotating disc that has 2 spring slowing it down. (look at my pictures to understand)

Let say I turn my disc 90 degrees clockwise and release it, it is going to oscillate a certain moment than stop.

I want to plot that function and to have a sinus function decreasing to 0 after a "x" number of period.

Thanks for your help,
Jean-Philippe

 

[JPGraphX]

For more detail about my project/issue: Link

 

[asimpson]

Look up balance wheel for mechanical watch.

 

[PNachtwey]

Interesting application. See this:

http://deltamotion.com/peter/Mathcad/Mathcad - T0C1 MassOnASpring-PID.pdf

The pdf uses a mass on a spring in a linear application but you would need to know the inertia and the spring constant as a function of rotation.

Everything can be calculate, even how to control the oscillation but it doesn't look like you are interested in control. You are after the natural frequency and damping factor. You can see this requires knowing the parameters for a second order differential equation.

Since you probably can't change your springs much you can 'tune' your instrument by placing weights near the edges of the rotating disks to increase the inertia and make the notes lower.





Peter Nachtwey
Delta Computer Systems

http://www.deltamotion.com