simtk.org

hi,

I read the following document and understood how to calculate the joint torque.
http://wiki.simtk.org/opensim/FrontPage ... entArm.pdf

Now i want to calculate d τθ/ d θ, where τθ is joint torque at θ, θ is the joint angle.
Is there any guidance for how to calculate it?

Thanks in advance,
jiang

Hi, Jiang. I think you would have to calculate that by numerical perturbation. You could use Simbody's Differentiator class to get a first- or second-order estimate, or just calculate it yourself by perturbing theta.

BTW, we have a more complete write-up of the moment arm calculation in this paper, although it doesn't directly address the problem you asked about.

Regards,
Sherm