Hi, I've been trying to use the API to compute moment arms for my musculoskeletal model for different values of the generalized coordinates. Out of around 15 dofs in the model, only 4 are truly independent and each of the remaining 11 are functions of one of the 4, linked through a 'CoordinateCouple...

I am trying to read an opensim model described in a .osim file into MATLAB, and then add a wrapping ellipsoid to the same. % I first initialize an empty WrapEllipsoid object W = WrapEllipsoid(); However beyond this point, I am not sure how to specify the dimensions, translation and XYZ rotation of t...

I am using version 2.2.1. All earlier versions seem to export the "moving muscle points" as fixed points when converting into the SIMM format. This leads to unreasonably high passive forces the affected muscles due to over-stretching. Thanks!

<t>When I export the gait2354.osim model into the corresponding joint and muscle files (Using OpenSIM version 2.2.1), SIMM fails to read in the muscles with "Moving Muscle points" such as the rectus femoris and the vastus. Is there some edit to the muscle file I could manually perform, so that these...

<t>Hi,<br/> One of the settings for CMC requires the user to specify a file containing "Kinematics for External Loads". This is by default always the IK motion file. I presume this has something to do with specifying Ground reaction forces during walking, since CMC does not use a ground contact mode...

<t>Hi,<br/> <br/> I was looking at how the reserve actuators work during CMC. It seemed like although their excitations remained constant during a time step (T=<t<T+0.01) the reserve actuator forces took on a different value at the start of the timestep (i.e at t=T). <br/> <br/> My understanding is ...

Hi,

The moment of inertia tensors for each body segment are reported in the osim file. Are these values taken w.r.t the center of mass of the body segment or the origin of the body frame??

Thanks
Ananth

Hi,

During static optimization in CMC, how many equations are used as constraints on the cost function??

Regards
Ananth

Are you referring to the 'joint moment' (Moment required to actuate the joint) or the 'joint reaction moment' (Moment of forces at joint contact, about the joint center)???

For joint reaction moment, you would have to use the 'JointReaction' analysis from the analyze toolbox.

<t>Thanks Matt,<br/> <br/> But the RRA states file only contains the joint coordinates and their velocities. So shouldn't we include the RRA controls file so that the values of the residual forces and joint actuators are known?? ..... and these would affect the values of the joint reaction forces. <...