Static Optimization for Stair Climbing

[Kang Li]

I have a question about applying GRF in Static Optimization for Stair Climbing.

The center of pressure location in vertical direction should be zero or the height of stair?

Thank you very much,

Kang

[Ayman Habib]

Kang,

The GRF is assumed to be measured in ground frame so you'd use the stairs height. Various tools in OpenSim transform the application point to the frame of the segment specified in the tool(usually calcn) before application. If your data does not come in this format you may need to perform some preprocessing to fix it.

In general you can verify if what you ended up with is correct as seen by OpenSim using the motion-data-previewer capability and synchronizing the display of the motion/trc file with the ground reaction forces file.

Good luck,
-Ayman

[Kang Li]

Thanks, Ayman

[Kang Li]

Now SO works for stair climbing after I apply the right GRF