simtk.org

Hello;
I use Lee-Son ToolBox v1.5. I am wonder why you write that this toolbox dosn't work for Kistler plate. I have Vicon and Kistler plates and toolbox works very good.
But I have problem. When I run ID the results what I obtain in OpenSim are
smaller then the results from Vicon... and I have very bad for RRA:

Computing average residuals between 0 and 2.25
Average residuals before adjusting torso COM:
FX=-13.989 FY=526.023 FZ=-5.91928
MX=-0.886387 MY=2.29242 MZ=-2.29544

RRATool.adjustCOMToReduceResiduals:
torso weight = 351.544
dx=-0.0065296, dz=0.00252141

dmass = -53.6394

Recommended mass adjustments:
ground: orig mass = 0, new mass = 0
pelvis: orig mass = 12.3311, new mass = 4.68096
femur_r: orig mass = 9.73906, new mass = 3.69699
tibia_r: orig mass = 3.88195, new mass = 1.47361

I am wonder what is wrong. GRF and CoP looks good. The same issue is for
every subject.

I hope that someone will give me some suggestion.
Best regards Michalina

Hi Michalina,

It's not possible to compare the outputs from different packages unless you have complete access to all the inputs. In ID these would be:
1. Model definition (particularly Joints and Mass Properties)
2. Input motion (in our case is described in terms of coordinates specified in 1.)
3. External Forces

Outputs would be Joint forces/torques and residuals in the likely scenario where the data is not dynamically consistent (F=Ma is not satisfied).

Item 1. above is the most likely cause of differences I suspect. If you can export the model and motion from your other packages into OpenSim then you should get similar answers but it's your call to decide if that would be worth the effort.

Best regards and please let us know if you continue to have questions,
-Ayman

Hi Michalina,

I'm Sangjun Lee, the developer of the Lee-Son's Toolbox.

Although our toolbox was developed based on data from AMTI force plates,
it seems to work fine with any kind of force plates so far.

If you have any problem in using our toolbox,
please contact us via our project page, https://simtk.org/home/lee-son
Then I can help you more quickly.

Thank you,
Sangjun Lee

Hi Michalina
I'm facing the same problem you faced, please advice my who you got it fix.
thanks
abeer