Search found 1043 matches

by Nicholas Bianco
Fri Nov 15, 2024 8:31 pm
Forum: OpenSim
Topic: Moving Path Point
Replies: 1
Views: 184

Re: Moving Path Point

Hi Maria,

If you could provide a minimum working example that reproduces the errors that you are encountering, along with the error messages, then we can assist with debugging your issue.

Best,
Nick
by Nicholas Bianco
Fri Nov 15, 2024 8:21 pm
Forum: OpenSim Moco
Topic: Solver Error
Replies: 1
Views: 71

Re: Solver Error

Hi Sakamo,

That error usually occurs when the optimizer struggles with the problem initial guess. Are you using the default initial guess or providing your own? Some general details about your problem would be helpful too.

Best,
Nick
by Nicholas Bianco
Mon Oct 28, 2024 9:04 am
Forum: OpenSim Moco
Topic: Required additional External Forces needed for MocoInverse
Replies: 1
Views: 156

Re: Required additional External Forces needed for MocoInverse

Hi Adam, Yes, you would likely need to add a foot-ground contact force element to your model to model the effects of the shoe/sole stiffness. You will probably need to use MocoTrack or a custom MocoStudy though, since your input kinematics will probably not produce correct forces at the feet "out-of...
by Nicholas Bianco
Sat Oct 19, 2024 9:46 am
Forum: OpenSim Moco
Topic: how to calculate muscle force
Replies: 11
Views: 683

Re: how to calculate muscle force

Hi Neha, I am not sure what you mean by this. If you problem converged and the controls are at the middle of the control bounds, then it probably converged to a local minima. There are many factors that might explain this: cost functions terms (and their weights), model complexity, choice of initial...
by Nicholas Bianco
Sat Oct 19, 2024 9:42 am
Forum: OpenSim Moco
Topic: Linear Velocity Constraint or Goal
Replies: 9
Views: 649

Re: Linear Velocity Constraint or Goal

Hi Cedric,

OpenSim (and Moco) uses SI units: meters, radians, Newtons, etc. Speed is measured in meters per second (m/s).

Best,
Nick
by Nicholas Bianco
Thu Oct 17, 2024 1:14 pm
Forum: OpenSim
Topic: calculation of center of pressure using Hunt and Crossley contact model
Replies: 3
Views: 520

Re: calculation of center of pressure using Hunt and Crossley contact model

Hi Park, You will be able to calculate forces that way, but I don't think the forces from a foot-ground contact model computed directly with IK kinematics will be very accurate. The IK solution will not capture the fine kinematic between the foot and the ground that are important for good force esti...
by Nicholas Bianco
Mon Oct 14, 2024 10:20 am
Forum: OpenSim Moco
Topic: Capturing terminal output in Google Colab
Replies: 2
Views: 277

Re: Capturing terminal output in Google Colab

Hi Ana,

If you're looking for the Ipopt output, you can add an ipopt.opt (Ipopt options) file to your working directory to specify where the Ipopt output should be directed to.

I haven't found a more general solution for this, but will let you know if I do!

Best,
Nick
by Nicholas Bianco
Thu Oct 10, 2024 10:41 am
Forum: OpenSim Moco
Topic: how to calculate muscle force
Replies: 11
Views: 683

Re: how to calculate muscle force

Hi Neha, Your problem appears to be infeasible (i.e., the problem cannot enforce the dynamics constraints in the direct collocation problem). I'm not sure about the MUMPS memory issue, but it might be related to Ipopt entering "restoration mode" in order to address the infeasibility issue. I would r...
by Nicholas Bianco
Thu Oct 10, 2024 10:25 am
Forum: OpenSim Moco
Topic: Determining Muscle Forces From MOCO Solution
Replies: 9
Views: 792

Re: Determining Muscle Forces From MOCO Solution

Hi Brodie, MocoTrack is just a tool for configuring a MocoStudy for tracking optimization problems. You can access the internally configured MocoStudy using "initialize": track = MocoTrack(); % your tracking problem configuration study = track.initialize(); solution = study.solve(); outputPaths = St...
by Nicholas Bianco
Wed Oct 09, 2024 9:14 pm
Forum: OpenSim Moco
Topic: Changing Weld Joints to Track Kinematics and Actuation around that Joint
Replies: 2
Views: 247

Re: Changing Weld Joints to Track Kinematics and Actuation around that Joint

Hi Adam, As long the actuators (including muscles, if relevant) are strong enough to produce the joint motion for the MTP joint, you should be able to get your problem to solve. However, we usually apply ground reaction forces to the model when using MocoInverse, and currently there is no good way t...