Including BushingForce in the MuJoCo Model

[SamerAbdelmoeti]

Hello,

Thanks for the handy package! I'm trying to convert the HYOID model of the head and neck, however the BushingForce of OpenSim is not included. The BushingForce in this case is the rotational stiffness and damping in the joints between the cervicals.

Since I'm new to MuJoCo, my question is how to include this in the MuJoCo XML, is it just the 'stiffness' and 'damping' parameters in the hinge joints of those bodies (cervicals)?

[aikkala]

Hi,

I'm not very familiar with the concept of a bushing force. It says in the OpenSim documentation that "damping is proportional to the deflection rate of change", which I guess means that the damping parameter changes dynamically as a parameter of the "deflection rate of change". I'm not sure if that can be achieved only by using the XML file, you might need to change the joints' damping and/or stiffness parameters programmatically during simulations (dof_damping and jnt_stiffness).