simtk.org

Hi all,
I would like to add passive joint torques to my model to prevent unusual joint angles during forward dynamics.
I can add the passive torque in older versions (like 2.0.2) but version 2.2 does not recognize the passive torque!! Is it deleted in new versions? If yes, why?
Cheers

Hi Sina,

Version 2.2 comes with an alternative (CoordinateLimitForce) that allows you to apply a force when a coordinate gets close to the end of the Range-of-motion. Please check the documentation on Doxygen. The XML snippet for it is included below, you'd include an instance of these under the <ForceSet> tag in the osim file.

Hope this helps,
-Ayman

<CoordinateLimitForce> <isDisabled>False</isDisabled> <coordinate>Unassigned</coordinate>
<!--Stiffness of the passive limit force when coordinate exceeds upper limit. Note, rotational stiffness expected in N*m/degree.--> <upper_stiffness>1</upper_stiffness>
<!--The upper limit of the coordinate range of motion (rotations in degrees).--> <upper_limit>0</upper_limit>
<!--Stiffness of the passive limit force when coordinate exceeds lower limit. Note, rotational stiffness expected in N*m/degree.--> <lower_stiffness>1</lower_stiffness>
<!--The lower limit of the coordinate range of motion (rotations in degrees).--> <lower_limit>0</lower_limit>
<!--Damping factor on the coordinate's speed applied only when limit is exceeded--> <damping>0.001</damping>
<!--Transition region width in the units of the coordinate (rotations in degrees).Dictates the transition from zero to constant stiffness as coordinate exceeds its limit.--> <transition>0.1</transition> </CoordinateLimitForce>

Thanks Ayman