Inverse Dynamics of an Underactuated System

[Priyanshu Agarwal]

Hi,

I'm working on simulating the inverse dynamics of a musculoskeletal model with some of the bodies having rotational joints and connected through multiple PointToPointSprings with the neighboring bodies. The angular position of these bodies should be determined by the solver as the spring forces determine the position of these bodies. So, the degrees of freedom corresponding to these bodies are constrained and are not independent. However, there isn't a well-defined coupler constraint between the coordinates of these bodies and the neighboring bodies as the dynamics of the system govern the spring forces and hence, the position of these bodies. How can I model such an underactuated system in OpenSim?

Thanks,
Priyanshu