Hi
I want to model the lifting task maneuver. I recorded the MoCap of the task, when I run the model there is no warning or error. But when I want to do the KinematicStudy, or optimization I get follwoing error:
Macro command : RunMotionAndParameterOptimizationSequence(5:5)> run
5.0) Kinematics (Operation: Main.Studies.MotionOptimization.Kinematics):
5.0.0) PreOperation (Operation: Main.Studies.MotionOptimization.Kinematics.PreOperation):
5.0.0.0) InitialConditions (Operation: Main.Studies.MotionOptimization.InitialConditions):
5.0.0.0) …Design variables have been updated.
5.0.0.1) …Load-time positions have been re-established.
WARNING! NAN reached!
Unexpected error in computational kernel
Constraint no. #0 in ‘Main.Studies.HumanModel.BodyModel.Right.ShoulderArm.Mus.ArtificialRake.LinCom2Drv’ above error tolerance 0.000001, error = 0.100000.
Constraint no. #0 in ‘Main.Studies.HumanModel.BodyModel.Left.ShoulderArm.Mus.ArtificialRake.LinCom2Drv’ above error tolerance 0.000001, error = 0.100000.
ERROR(OBJ.MCH.KIN3) : C:/Users/ak…li/M…s/M…g/Model/Kinematics.any(74) : MotionOptimization.InitialConditions : Kinematic analysis failed in time step 0
Can anyone help me on this? I don’t know how to fix it.
Hi Amin,
what motion capture system do you use? can you upload a c3d file, so we can have a look what happened?
Hi Amir
We use AMDI force plate. The gravity force is in z direction, so I already change it in the MoCap file.
Could you please let me know what software you suggest for post-processing the c3d file? We are thinking to purchase one but we don’t know what options we have.
Attached is the c3d file that I use.
Thank you for your help.
Hi Amir
We use AMDI force plate. The gravity force is in z direction, so I already change it in the MoCap file. The sample rate is 120Hz.
Could you please let me know what software you suggest for post-processing the c3d file? We are thinking to purchase one but we don’t know what options we have.
Attached is the c3d file that I use. It is a 5sec lifting task.
Thank you for your help.
Amin,
I don’t think that there is a problem with your MoCap system in general. I have attached a MoCapModel with your C3D based on the lower extremities only. I recommend to look first at the lower extremities and if that works nice add the upper extremities (if needed at all). It loads and it starts the MotionAndParamterOptimization, however, there are still several issues with it. Main issue is that several markers are dropping out: in AnyBody, when a marker is dropping out it will go to the origin (coordinate 0,0,0). You can see that when you run the optimization.
Hi Amir,
Thanks for the file. I guess our marker placement was not accurate. Is there any instruction on marker placement for MoCap model?
Also, please let me know if you know a good software for post-processing the c3d files.
Regards,
Amin
Amin,
I think the placement is ok. It’s just that the cameras did lost the vision to the markers, or the tracking system made some errors. Are you using Vicon, Qualisys, or…?
Hi Amir,
We are using Vicon. I fixed the issue of missing markers as you suggested. Model runs good now. However, when I run the inverse-dynamic it stops at step 91/139 with the following error.
I attached the new c3d file for you.
- InverseDynamics (Operation: Main.Studies.InverseDynamicStudy.InverseDynamics):
0.0) PreOperation (Operation: Main.Studies.InverseDynamicStudy.InverseDynamics.PreOperation):
0.0.0) InitialConditions (Operation: Main.Studies.InverseDynamicStudy.InitialConditions):
0.0.0) …Design variables have been updated.
0.0.1) …Load-time positions have been re-established.
0.0.2) …Kinematic analysis completed. The kinematic constraints have been resolved.
0.0.3) …Initial conditions are fully updated.
- Inverse dynamic analysis…
ERROR(OBJ1) : C:/U…s/a…i/M…s/M…2/M…l/JointsAndDriversOptimized.any(12) : JntDriverTrunk : Time, ‘t’, has an invalid value for this interpolation
Did you run the optimization completely to the end? That sounds that you stopped the Optimization Study at step 91.