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Induced Acceleration Analysis (IAA) from static optimization

Posted: Wed Oct 15, 2014 2:25 pm
by yoannblache
Good afternoon every one,

I am currently trying to perform an Induced Acceleration Analysis (IAA) with opensim 3.2.
Briefly I performed a static Optimization with an upperLimb model to know the muscle forces and activations during a lifting task.
Now I would like to know the contribution of each muscle in the box linear acceleration (the box is a segment of the model)
If I have understood performing IAA from static optimization required the following input files:

IAA_settings.xml
- compute_potentials_only : true
- bodyName : box (in our case)

other files
-model.osim
-actuators_settings.xml (the same file as the one for static optimization)
-externalForces.xml, containing external forces, torques and point of application (in our case we measured the forces and torques between the hand and the handgrip of the box, but not the ground reaction forces)
-inverse_kinematics_results.mot (no RAA in our case because we did not measure the ground reaction forces)

Then I should multiply my results by the actuators forces obtained with the static optimization.


When I performe the IAA with these previous settings I obtain the foolowing error message


Code: Select all


Adding force object set from E:\Projet_Yoann\muscle_contribution_box_acceleration\sujets\DamGd\results_constraints\Conf_SO_Actuators.xml

Loading coordinates from file E:\Projet_Yoann\muscle_contribution_box_acceleration\sujets\DamGd\results_constraints\Results_IK.mot.
Storage: file=E:\Projet_Yoann\muscle_contribution_box_acceleration\sujets\DamGd\results_constraints\Results_IK.mot (nr=429 nc=23)


Low-pass filtering coordinates data with a cutoff frequency of 6...

Found 857 state vectors with time stamps ranging from 0.87 to 9.43.
Old version storage/motion file encountered
Storage: file=DamGH6H1_2f.mot (nr=4281 nc=10)
.. assuming rotations in Degrees.
ExternalForce::Reaction
Data source being set to DamGH6H1_2f.mot
Executing the analyses from 5 to 6...
Performing Induced Accelerations Analysis
time = 5

Exception:
  ArrayPtrs.get: Array index out of bounds.
  

If I perform the IAA without the external forces, it runs perfectly

Should I add a constraint in the IAA settings file such as <RollongOnSurfaceConstraint name="Reaction"> (Reaction is the name of my external forces in the externalForces.xlm file)

My second questions concern the results, when I get some (without external forces), I obtaine 6 values for each actuator. For example for the anterior deltoid I get:

DELT1_X, DELT1_Y, DELT1_Z, DELT1_Ox, DELT1_Oy, DELT1_Oz

Could someone tell me to what these values refer?

Thank you in advance

Yoann

Re: Induced Acceleration Analysis (IAA) from static optimiza

Posted: Fri Oct 17, 2014 6:15 am
by yoannblache
Hello everyone,

finally I found the solution to run the IAA with external forces.

Nevertheless I still do not understand why I obtain 6 values for each muscle.

Any Idea ?

best regards

Yoann

Re: Induced Acceleration Analysis (IAA) from static optimization

Posted: Fri Jan 06, 2017 7:58 am
by justinwager
Hi Yohan,

What was the issue with your IAA setup? I am having a similar problem.

Justin