no difference in gait pattern with or without load

[Karishma Sebastian]

hie..!!

I am working on a full body model. I made changes to the model by adding an external load(eg. a backpack) and describing the points on the back where the forces due to this load would occur. I took the normal.mot file from the example gait2392_simbody folder and applied to both my models i.e one with load and 1 without load.
My problems:

1. While plotting I selected the Y quantity as normal gait but no quantity shows up for my model when the 'select motion' window opens up.
2. Now suppose if I plot the Y quantity as normal gait and select 'pattern' in the 'select motion Quantity' window it doesn't show muscles instead only the coordinates data(eg. knee flexion,lumbar_extension) from the coordinates window.
3. Let's say I selected one of these angles(y-axis) and plotted it against the normal gait (X-axis) for both with or without load the graph is same for both which of course is wrong.
4. Should I be using my own .mot file? aren't mot files only for verification purposes?
4. Shouldn't there be a change in how the model looks when we add a load on the back( like a model without a load is upright while a model with load should be hunchbacked)? Should this difference come on its own when I add the load using Matlab or should I programmatically bring this change by changing the lumbar angles?

[Thomas Uchida]

1. While plotting I selected the Y quantity as normal gait but no quantity shows up for my model when the 'select motion' window opens up.

The "Plotting" section in the Confluence documentation describes how to use the plotter (https://simtk-confluence.stanford.edu/d ... m/Plotting).

2. Now suppose if I plot the Y quantity as normal gait and select 'pattern' in the 'select motion Quantity' window it doesn't show muscles instead only the coordinates data(eg. knee flexion,lumbar_extension) from the coordinates window.

The "normal.mot" file contains only coordinate data (see https://simtk-confluence.stanford.edu/d ... t%29+Files).

3. Let's say I selected one of these angles(y-axis) and plotted it against the normal gait (X-axis) for both with or without load the graph is same for both which of course is wrong.
4. Should I be using my own .mot file? aren't mot files only for verification purposes?
4. Shouldn't there be a change in how the model looks when we add a load on the back( like a model without a load is upright while a model with load should be hunchbacked)? Should this difference come on its own when I add the load using Matlab or should I programmatically bring this change by changing the lumbar angles?

You either need to specify different values for the model's coordinates or generate a simulation that computes these values. I suggest working through the tutorials and looking at the examples here: https://simtk-confluence.stanford.edu/d ... +Tutorials.

[Karishma Sebastian]

Thank you so much for your clarification. I now understand the coordinates.