Search found 48 matches

by Brian Umberger
Fri Apr 09, 2021 10:19 am
Forum: OpenSim Moco
Topic: Matlab version of example2DWalking with metabolic cost minimization
Replies: 20
Views: 3582

Re: Matlab version of example2DWalking with metabolic cost minimization

Hi Ross, Thanks for the questions. 1) I think that is the new behavior in Moco 1.0.0. In my opinion, the output file behavior is an improvement, as it should only write that out if you want, and to the filename that you want (i.e. using solution.write('filename.sto')). The objective and its terms ca...
by Brian Umberger
Wed Apr 07, 2021 7:09 pm
Forum: OpenSim Moco
Topic: Matlab version of example2DWalking with metabolic cost minimization
Replies: 20
Views: 3582

Matlab version of example2DWalking with metabolic cost minimization

Hello All, First, a big congratulations to Nick, Chris, and the whole team for the 1.0 release of Moco! It is a major contribution to the biomechanics community. One of the great additions in the new release is a smooth muscle energetics model, contributed by Antoine Falisse. Antoine provided a C++ ...
by Brian Umberger
Sun Apr 19, 2020 1:06 pm
Forum: OpenSim Moco
Topic: Matlab version of example2DWalking
Replies: 47
Views: 6165

Re: Matlab version of example2DWalking

This is a reply to Mritula: Except for a few additions I made, everything in the Matlab version of example2DWalking is based on a C++ example Antoine Falisse created (located in Resources\Code\CPP). To provide targets for the tracking problem, Antoine used results from walking simulations in his rec...
by Brian Umberger
Mon Mar 23, 2020 4:49 pm
Forum: OpenSim Moco
Topic: Matlab version of example2DWalking
Replies: 47
Views: 6165

Re: Matlab version of example2DWalking

Hi Ross, You can make the tendon forces periodic in the Matlab example with something like this for i = 1:model.getNumStateVariables() currentStateName = string(model.getStateVariableNames().getitem(i-1)); if endsWith(currentStateName,'/normalized_tendon_force') if contains(currentStateName,'_r') sy...
by Brian Umberger
Sat Mar 14, 2020 4:25 pm
Forum: OpenSim Moco
Topic: Matlab version of example2DWalking
Replies: 47
Views: 6165

Re: Matlab version of example2DWalking

Hi All, With regards to Aaron's last question, the best source for understanding the implicit formulation and its numerical advantages over the typical explicit formulation for the EOM is this paper by Ton van den Bogert: https://www.ncbi.nlm.nih.gov/pubmed/22102983 and for the muscle model equation...
by Brian Umberger
Thu Mar 05, 2020 5:43 pm
Forum: OpenSim Moco
Topic: Matlab version of example2DWalking
Replies: 47
Views: 6165

Re: Matlab version of example2DWalking

Hi Karthick, Here is a potential solution that arose in trying to address a similar issue with my own model. After you create the model object, set the tendon compliance dynamics mode to "implicit" modelProcessor.append(ModOpTendonComplianceDynamicsModeDGF('implicit')); You can then comment out the ...
by Brian Umberger
Mon Feb 24, 2020 12:16 pm
Forum: OpenSim Moco
Topic: Tropter Solver
Replies: 9
Views: 1125

Re: Tropter Solver

Hi Aaron, I was also considering optimizing contact sphere parameters in one of our application where it might actually be worth the effort. I appreciate the discussion in this thread about whether that is worthwhile, and suggestions for more efficient ways to go about it. Regardless, I do have a pr...
by Brian Umberger
Mon Feb 24, 2020 10:16 am
Forum: OpenSim Moco
Topic: Matlab version of example2DWalking
Replies: 47
Views: 6165

Re: Matlab version of example2DWalking

Hello Karthick, Thanks for your patience. I became busy with work and was not checking the forum. For the example, I used a finer mesh and tighter tolerance because in the initial solutions I obtained there were oscillations in the GRFs, which appeared to be due to oscillation in the tendon forces f...
by Brian Umberger
Sun Jan 26, 2020 1:36 pm
Forum: OpenSim Moco
Topic: Matlab version of example2DWalking
Replies: 47
Views: 6165

Re: Matlab version of example2DWalking

Hi Aaron, I'll preface this response by noting that varying the target speed was something I only played around with when I was starting out with Moco and did not investigate thoroughly or try to fine tune. In addition to widening the bounds on the states I did also widen the bounds on the final tim...
by Brian Umberger
Thu Jan 16, 2020 7:03 pm
Forum: OpenSim Moco
Topic: Matlab version of example2DWalking
Replies: 47
Views: 6165

Re: Matlab version of example2DWalking

Hi Aaron, Your post is a few days old so maybe you have already worked through this, but I did try faster speeds for the predictive case when I was first testing this out. I solved a sequence of problems with progressively faster target speeds and easily got the model to run at moderate speeds (I fo...