View Full Version : Trying to add a 2-segment swing leg to the spring-mass model?

12-18-2007, 02:47 AM
Hello Colleagues,

Is anyone else working on this problem?

The spring-mass model is an effective tool for understanding the physics of
a human runner. I think the model could be expanded to help explain the
Preferred Step Frequency (PSF) as a function of velocity (1) and the O2
consumption minimization near the PSF (2).

This may be accomplished by simultaneously integrating the equations of
motion for the spring-mass and the swing leg in a single RK4 system. If the swing
leg is treated as a double compound pendulum, the accelerations from the
spring mass model can be applied to the swing leg pendulum.

I believe that I have been able to generate correct equations of motion for
a double pendulum in an accelerating frame with a Lagrangian formulation in
MathCad8. But, they contain monstrous expressions that take hours to check and
verify. System integration is the next step.

If you are interested in collaborating on this analysis, or if you have any
references in this area, please send me an email.


Ted Andresen
Math Department (SP/G)
St. Petersburg College
Hot&Humid, Florida

(1) _http://members.aol.com/EasyExperiments/PSFVsSpeed.gif_
(2) _http://members.aol.com/EasyExperiments/Cavanagh2.gif_

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