Search found 8 matches

by Hongyuan Chen
Fri Sep 13, 2024 10:47 pm
Forum: OpenSim
Topic: Cannot play the animation after inverse kinematics succeed ,even by loading the mot file obtained from the inversion
Replies: 4
Views: 1153

Re: Cannot play the animation after inverse kinematics succeed ,even by loading the mot file obtained from the inversion

Hello Ayman, Thanks for the analysis and answers you gave. Actually, I got the marker position by optitrack acquisition and then solved the individual joint angles inversely by modeling the upper limb. But as I said before, in some cases, after the inverse solution is finished, an entry of the inver...
by Hongyuan Chen
Thu Sep 12, 2024 11:25 pm
Forum: OpenSim
Topic: Cannot play the animation after inverse kinematics succeed ,even by loading the mot file obtained from the inversion
Replies: 4
Views: 1153

Re: Cannot play the animation after inverse kinematics succeed ,even by loading the mot file obtained from the inversion

I can see the red cross in the right below of the messages window. A java.lang.ArithmeticException exception has occurred. Detailed error message: java.lang.ArithmeticException: / by zero at org.opensim.threejs.ModelVisualizationJson.calculateWrapPointsToVisualzerPointsMapping(ModelVisualizationJson...
by Hongyuan Chen
Thu Sep 12, 2024 1:07 am
Forum: OpenSim
Topic: Cannot play the animation after inverse kinematics succeed ,even by loading the mot file obtained from the inversion
Replies: 4
Views: 1153

Cannot play the animation after inverse kinematics succeed ,even by loading the mot file obtained from the inversion

Helle, everyone! I'm having problems using the MobL_ARMS_unimanual model in Upper Extremity Dynamic Model. I have changed the osim file of the model (including range limits and marker point locations). In some cases this works, but in some cases, after I successfully run the inverse kinematics tool,...
by Hongyuan Chen
Tue Jul 23, 2024 7:09 pm
Forum: OpenSim
Topic: How to record the errors output using InverseKinematicsTool in python
Replies: 2
Views: 691

Re: How to record the errors output using InverseKinematicsTool in python

Thank you so much Aaron,

I've noticed the '_ik_marker_errors.sto' file in directory of my python file. I used to think it will appear in the folder of my model. By following your way, I've succeeded in recording the errors output.

Hongyuan
by Hongyuan Chen
Tue Jul 23, 2024 4:15 am
Forum: OpenSim
Topic: How to record the errors output using InverseKinematicsTool in python
Replies: 2
Views: 691

How to record the errors output using InverseKinematicsTool in python

I am trying to using the python and opensim4.5 to do the IK with python. The following sentences is written: import opensim as osim model = osim.Model('mypath/model.osim') state = model.initSystem() ik_tool = osim.InverseKinematicsTool() ik_tool.setModel(model) ik_tool.setMarkerDataFileName(trc_file...
by Hongyuan Chen
Thu Jun 27, 2024 7:25 pm
Forum: OpenSim
Topic: Cannot lock the joint using Python API with Opensim 4.5
Replies: 2
Views: 582

Re: Cannot lock the joint using Python API with Opensim 4.5

Thank you very much for your response. As a first-time user of the OpenSim API, I'm not yet clear on all the differences. I tried what you suggested, and it turns out that setValue only changes the current state, having no effect in the InverseKinematicsTool(). However, using set_default_value() and...
by Hongyuan Chen
Thu Jun 27, 2024 6:58 am
Forum: OpenSim
Topic: Cannot lock the joint using Python API with Opensim 4.5
Replies: 2
Views: 582

Cannot lock the joint using Python API with Opensim 4.5

I attempted to use the Python API to achieve the functionality of locking certain values in the Coordinates section within OpenSim. The overall code is shown below. In Python, I first perform IK on the first 50 data points to obtain the mean values, then I lock the trunk coordinates (such as 'r_x', ...
by Hongyuan Chen
Mon May 27, 2024 10:55 pm
Forum: OpenSim
Topic: forward kinematics (jacobian) calculation and muscle jacobian (muscle moment arm) calculation
Replies: 1
Views: 876

forward kinematics (jacobian) calculation and muscle jacobian (muscle moment arm) calculation

Hello, I am new to OpenSim and SimTK and I am trying to use upper extremity dynamic model to simulate human movements and get two matrixes ( Jacobian J and muscle Jacobian Jm). The Jacobian is a matrix of partial derivates that relates small end-effector (hand) velocity V with small joint angle chan...