In the literature and this forum, I have seen that the Hunter-Crossley Force has been applied to model the contacts on plane and sphere geometries. The paper "Seth A, Sherman M, Reinbolt JA, Delp SL. OpenSim: a musculoskeletal modeling and simulation framework for in silico investigations and exchan...

Thanks Ayman for the quick reply. To clarify: the Logger.addSink(JavaLogSink()) was originally called only once at the beginning of the script, not in the loop. However, when RRATool was called in a loop to run multiple times, Matlab threw a Java exception as described in the original post. With som...

When I initiate a model from a model file path (e.g. Model(filePathToModelFile)), Matlab throws a Java exception as below: Java exception occurred: java.lang.NullPointerException: null upcall object in OpenSim::LogSink::sinkImpl at org.opensim.modeling.opensimSimulationJNI.new_Model__SWIG_1(Native M...

Hi,

If I script in Matlab and want to change the objective function in static optimization or CMC for a gait simulation, what would be the best way to do it?

Thanks!

Xiao

Hi, I am trying to use printCurveToCSVFile method in Thelen2003Muscle to see how the tendon force-length curve looks like after I change tendon parameters. I am scripting in Matlab, and so far cannot get it to work. I think I did not correctly provide the CurveType argument, which requires an Enumer...

If eventually I would like to use Matlab script to automate the process so that I can simulate eccentric contraction at various muscle activation levels and look at the developed muscle forces, what would be the best way of doing it?

Hi, I am working on simulating muscle eccentric contraction as done in animal experiments with in vitro setup. Basically, the muscle is first being fully activated, and then stretched to certain extent, like 20% of Lo. The muscle forces are being measured. I built a simple model with one muscle and ...

Hi, I am trying to use the Gait2392 model to run CMC. Both the model and the walking data come with the OpenSim 3.2 installation package. I got everything to run appropriately from scaling, IK to RRA. But, the CMC always generated small variation in the ankle angle during stance phase, which RRA doe...

Hi, I was trying to upload a picture of my simulation results and ask questions about these results. But, the forum did not allow me to upload the picture as an attachment, saying that "Sorry, the board attachment quota has been reached." Could the administrator of the forum fix this? Thanks! Xiao

<t>Hi Ayman,<br/> <br/> Thanks a lot for your response!<br/> <br/> I am thinking to call OpenSim from Matlab to pull out muscle parameters necessary for the computation in Matlab.<br/> <br/> For example, I specify arm posture (joint angles) in Matlab; Matlab passes it to OpenSim; then OpenSim calcul...