Zero Fiber Length Error in Millard2012 Muscle when running CMC with MoBL-Arms Upper Extremity Model
Posted: Wed Apr 19, 2023 2:53 pm
Hello,
I have been troubleshooting with an error that I keep getting when I run CMC using the MoBL-ARMS Upper Limb model (Saul et al., 2015). The error reads:
The motion of interest is a high reach, and I have successfully used CMC with this motion from other subjects. Furthermore, I have successfully ran CMC for other motions with the scaled model for this subject. For some reason this particular trial is not working, and I have been exploring different solutions to address this problem. I have attached the scaled .osim file and the .mot file for reference.
I have looked at other related forum posts (viewtopicPhpbb.php?f=91&t=13307&p=38202&start=0&view=) and attempted the following solutions:
Thank you in advance for any suggestions!
Kaleb
I have been troubleshooting with an error that I keep getting when I run CMC using the MoBL-ARMS Upper Limb model (Saul et al., 2015). The error reads:
Code: Select all
Exception:
Exception caught in Millard2012EquilibriumMuscle::calcMuscleDynamicsInfo
from DELT1
Exception caught in Millard2012EquilibriumMuscle::calcFiberVelocityInfo
from DELT1
SimTK Exception thrown at MuscleFixedWidthPennationModel.cpp:169:
Error detected by Simbody method
MuscleFixedWidthPennationModel::calcPennationAngularVelocity: Fiber length
cannot be zero.
(Required condition 'fiberLength > 0' was not met.)
I have looked at other related forum posts (viewtopicPhpbb.php?f=91&t=13307&p=38202&start=0&view=) and attempted the following solutions:
- Making the tendon of DELT1 rigid
- Reducing the tendon slack length of DELT1
- Reducing stiffness properties of BIClong, TRIlong, and DELT1. I attemped this since I noticed some larger passive forces, especially in BIClong
- Applying new scaling settings for this subject and then running inverse kinematics and CMC with the new scaled model
- Adjusting numerical derivative step size in CMC settings
Thank you in advance for any suggestions!
Kaleb