import the cadence varied with each crank angle

Main Forum
21

Hi sylvaincarbes
If the cadence is not constant, how can I import the variable cadence file into the main.any?
And how to set the starting angle at the CrankMomentPhase?
Thanks a lot
Chi-Yi

22

Hi Chi-Yi,

If the cadency is non constant you will need to use another driver for the cadency.

Which driver you will need depends on the variation you have in the cadency throughout one rotation

If have an “arbitary” variation you may want to use an AnyKinEqInterPolDriver for details please refer to the reference manual for details. Also see the tutorial
http://www.anybodytech.com/fileadmin/AnyBody/Docs/Tutorials/Making_things_move/intro.html

The CrankMomentPhase can be adjusted in the top of the main file in the parameter section.

Note that the motion of the the crank and the crank moment is supplied separately. So there one function defining the motion and another one for the moment. The moment function is defined as a function of the crank angle though.

Best regards
Søren

23

Dear Søren
I know that the motion of the the crank and the crank moment is supplied separately, and I adjusted the motion of the the crank already.
But the section of crank moment on CrankMomentPhase…
I’m not sure the means of -15 of
“AnyVar CrankMomentPhase = -15*pi/180”?

Thank you

24

Hi Chi-Yi,

The CrankMomentPhase is basically an angle, so the unit is Radians. The -15 is a value in degrees that is converted in radian multiplying it by pi/180. So the phase is equal to -15 degrees, or -0.26 radians.

Best regards, Sylvain.

25

Hi Sylvain
I adjusted the cadence by the txt file at the “CrankRotation” in the “BikeFrameAndWheels”.
In the “main.any”, I changed the cadence to the average rpm.
And how shold I adjust the part of “CrankMomentPhase”, it’s basically an angle(to have the right starting angle at t=0), I started from 0 deg?

26

Hi,

I can’t give you an exact number. It depends on the starting angle of the motion you have inputed in “CrankRotation”.

But just remenber that if you use a non constant cadence for the crank rotation then the crank moment should follow the cadence, and that mean you can’t use the current definition (using a cos funtion and a constant frequency). You probably have to use a text file for the moment similarly to the motion.

Best regards, Sylvain.