Dear All: I'm trying to get the accelerations from a model with a StatesTrajectory object created from a .sto file through MATLAB . The sto file is generated from StatesReporter Analyze Tool in OpenSim GUI (see the attachment). The code is as below: import org.opensim.modeling.* osimModel = Model('s...

ed_morra wrote:Hi Jack,

Which data set are you working with? (Third, Fourth, etc)

- Ed -

Dear Dr Morra:
Sorry for replying late!
I am using the overground motion data including EMGs in 4th-JW data set on the JW musculoskeletal model.

Best regards
Jack

Thanks, Dimitar. The problem was caused by petallar ligments which jointed the calculation during the inverse dynamics. And its scale factor of force magnitude decides how much force would be produced on the knee joint acting like an external load. Thanks, Linjie Dear Dr Wang: I am a PhD graduate f...

SO can approximate the muscle behavior linearly (f = fmax * a) or non-linearly (f = fmax * fl * fv * a). When you choose the check box you use the non-linear model which accounts for the length and velocity of the fibers https://github.com/opensim-org/opensim-core/blob/master/OpenSim/Analyses/Stati...

Hi, When a muscle produces zeros force it can be that the muscle is not required. It also can mean that the muscle is at a bad operational region (too short). If it is the second case you can check the muscle activations (for saturation). You may think that if you increase the maximum isometric for...

Dear all: The tutorial " Working with Static Optimization " on the OpenSim website has pointed out that, when muscles are not strong enough to produce required accelerations, static optimization will produce only invalid results (zero force) that indicate "here are wrong". (Figure below is a sample)...

Dear All: I performed inverse dynamics (ID), static optimization (SO) and MuscleAnalysis using gait2392 model and the same motion and ground reaction force of subject01 sample data , while finding that the moment calculated from ID (in "inverse dynamics.sto" file) do not equal to the sum of the prod...

The model is from the project data "Grand Challenge Competition to Predict In Vivo Knee Loads" Perhaps your question has been answered in the Forum associated with the "Grand Challenge Competition to Predict In Vivo Knee Loads" project ( https://simtk.org/plugins/phpBB/indexPhpbb.php?group_id=413&p...

Dear All: I performed inverse dynamics using the lower limb model with implants (see the attached image) for normal gait, based on kinematic motion data and GRF data. The inverse kinematic is normal and correct, which produced good animation of gait motion. The ankle moments in the output sto file f...

Dear All: I performed inverse dynamics using the lower limb model with implants (see the attached image) for normal gait, based on kinematic motion data and GRF data. The inverse kinematic is normal and correct, which produced good animation of gait motion. The ankle moments in the output sto file f...