one force plate, two feet

[Julie Ellis]

I am working on modelling a push-up task with a full body model. We collected external load data with 3 force plates, with each hand on a separate force plate and both feet on the third. When using inverse dynamics what would be the best method of applying the forces to both feet? Will the they require a weld-constraint to fixate them to the ground?
Thanks for your help in advance!
Julie Ellis

[jimmy d]

Hi Julie,

You wont need a weld constraint. I would suggest splitting the ground reaction forces evenly across the two feet. You will need to calculate the location of feet application to the ground from kinematics and apply the forces at those locations.

Hope that helps,
-James

[Sami Khan]

Hello James,

I have a similar Problem. Could you explain how to calculate the location of feet application to the ground from kinematics?

thanks
Skipper141

[jimmy d]

Hi Skipper,

That will depend on the marker set you have used for your feet. Using the positions of the markers, and knowing that the vertical position of the ground is zero, you should be able to use some logic to get a reasonable estimate.

Hope that helps,
-james

[Sami Khan]

Thank you James!