I stole it from numerous Rick Neptune papers!

It would be nice if the weights could be time-varying, e.g. heavy/light weight during portions of the gait cycle when variance is low/high. Nick, is this possible (either now, or potentially)?

Ross

Hi Oliver, I've done parameter optimization with MocoTrack before (adjusting prosthesis stiffness, for example). I think Nick mentioned this already but in your initial guess for MocoTrack, is the parameter included in the guess? If I'm starting from a solution that didn't have parameter optimizatio...

Hi Ziang, I think these errors are typically from things in the model that violate IPOPT's expectations of the state equations being "smooth and continuous". I would guess in your model the best candidates for where things might not be smooth and continuous are the wrapping geometries. Echoing Nick'...

Hi Hojin, I've used the Goal Nick mentioned to minimize the deviations of the torso in global frame, it worked well. You could try that Goal with a high weight and see if it makes the deviations of the arms small enough for your purpose. If you want the deviations to be literally zero, I think you'd...

5x wow, I'm surprised it makes that much of a difference. I will have to try this. Nick, is there a way of assessing/reporting the goodness-of-fit of the polys? Apologies if this is obvious, nothing jumped out at me in the documentation. My struggle when exclusively using polynomial functions for mu...

Glad the codes are helpful! I don't normally track the GR moments, just the forces. My rationale is if the tracking of the GRF and of the kinematics are both good, and if the model itself is good, then the CoP should look good too (a gauge of validity). But if you want to make sure the model's CoP i...

What Aaron described for (2) is how I've previously gotten joint moments from a Moco solution. If you have other actuators at the joint besides muscles, you'd want to add those too. You can also get joint forces and moments from doing a Joint Reaction Analysis, but I'm not sure I'm doing that right ...

Hi Kayla, If the model's GRF are from the usual foot-ground contact elements, the states being periodic should also result in periodic GRF. Did you set all the generalized speeds (e.g. joint angular velocities) to be periodic too? Below is the code I use to get states and controls that are periodic ...

Hi Hojin,

Ligament length isn't a control, state, or parameter, so I don't think it can be directly bounded.

You could bound the allowed ranges on the DOF spanned by the ligament to indirectly limit its length.

Ross

Hi Azarang, Apologies if I'm missing some details here, I wasn't sure if I fully followed what your workflow is: If you are tracking kinematic data using MocoTrack or MocoStateTrackingGoal, the GRF produced by contact elements on the feet will not typically resemble experimentally measured GRF very ...