Static Optimization actuators

[Alejandra Prado]

Greetings,

I've been trying to perform the tutorial using the latest version of the model and I get the message of Static Optimization Failed. However I don't know which actuators should I add to have a better result and the analysis to run faster.

Can you give me more information on how to proceed. I want to use the model to evaluate static poses with different lifting load values.

Thanks,

Alejandra

[Jacob J. Banks]

Alejandra,
Thanks for you interest in our model.

Sounds like you are a new to OpenSim?

At any rate, the best way to add residual actuators is to use the 'createActuatorsFile.m' that is now downloaded with OpenSim (and attached here). This will create a residual file (*.xml) accounting for every DoF. Note: you will need to have Matlab working with Opensim. If you don't have access to Matlab, I can send you a residual *.xml file.
If you do and run the script, you will still most likely need to manually increase the residual magnitudes on the Pelvis (the base segment) or feet (to simulate GRFs), by a factor of 10,000 (if I recall). This is crucial if you do not have GRFs, as the model needs something to 'hold it up' (and this is where I think things may be going wrong for you). If you do have GRFs, adding residuals can still help with solving efficiency (as you note)... however given the number of DoF and MTAs in the model it still takes a little time to solve each frame.

Otherwise, try opening the log file and see if you can get more specifics as to why it fails. Could just be that your static task (i.e., pose and lifting load) are too difficult for the base model. In which case, I would suggest increasing the MTAs strengths.

Let me/us know how it goes and if you have any other questions.
Jake Banks