the problem of recognising local frame during joint reaction analysis

[Linjie Wang]

Hi, there.

I am trying to use joint reaction analysis to get the ankle forces and moments. In the settings, there is one to input the frame name in 'express_in_frame'. However, whenever value, for instance, 'ankle_angle_l' or 'knee_angle_l' in the <Coordinate name=>, the output result always gave the ones in ground frame. So I presume the system didn't recognise the local frame or I input the wrong ones. Does any one know how to sort it out?

Many thanks,
Linjie

[Thomas Uchida]

In the settings, there is one to input the frame name in 'express_in_frame'. However, whenever value, for instance, 'ankle_angle_l' or 'knee_angle_l' in the <Coordinate name=>, the output result always gave the ones in ground frame.

The express_in_frame property must be either "ground", "parent", or "child". Please see the "Joint Reactions Analysis" page in the Confluence documentation (https://simtk-confluence.stanford.edu:8 ... s+Analysis, "Input" section) and the XML Browser entry for JointReaction:

Code: Select all

<!--Choice of frame (ground, parent, or child) in which the calculated reactions are expressed. ground body is default. If the array has one entry only, that selection is applied to all chosen joints.-->
<express_in_frame>ground</express_in_frame>

[Linjie Wang]

My bad. I misunderstood the meaning. Thanks a lot, Tom! Thanks