Limb Center of Mass during subject scaling

Upload mocap files and get an optimally scaled OpenSim model and IK back in minutes. Share your data with the community. Browse and download biomechanics data. Hosted by Stanford University.

Available at https://addbiomechanics.org
POST REPLY
User avatar
Duncan Lee
Posts: 24
Joined: Thu Sep 14, 2023 10:15 am

Limb Center of Mass during subject scaling

Post by Duncan Lee » Thu Jun 27, 2024 5:38 pm

Hello,

I was wondering whether AddBiomechanics takes into account limb center of mass position in the subject model during subject scaling. I have noticed that in limb local coordinates, the position coordinates of the COM do not change between the unscaled model and the scaled model. For example, the shank COM coordinates are (0,-0.1867,0) with respect to the shank origin at the knee joint, and this is true in both the scaled and unscaled models. Is limb COM taken into account, and if so how does the specified COM and limb inertia affect the inverse dynamics?

Thank you,
Duncan Lee

User avatar
Nicholas Bianco
Posts: 1050
Joined: Thu Oct 04, 2012 8:09 pm

Re: Limb Center of Mass during subject scaling

Post by Nicholas Bianco » Sat Jun 29, 2024 11:23 am

Hi Duncan,

We tried including limb center-of-mass optimization in AddBiomechanics, but found that the benefit was neglible relative to the added complexity in the dynamics fitting optimization.

-Nick

POST REPLY