Model editing issue : muscle stiffness & external force

[YONGJIN JO]

Hi, everyone.

I'm trying to see change of hemiplegic gait with cable assistance. I'm using Moco to see the change of gait according to condition. However, I'm struggling to implement 3D hemiplegic gait. While editing model code to add patients characteristics, the change couldn't reflect the patients motion.

I want to implement the muscle stiffness like patients so that it could affect the model's gait. So I added stiffness to my .osim model file. However, that doesn't affect the calculation result. I just added stiffness or edited strain_at_norm_force, but both doesn't show change. is there any way which can make muscle stiffness so that it can affect the gait?

I also want to implement cable assistance. Unlike exoskeleton assistance which is normally aligned with joint, I tried to make cable force assistance. however as the force is a linear one and not act to joint directly, I'm not sure how to implement it. I want to make a force property which is applied to upward(opposite direction of gravity). How can I set this up and make trajectory of it?

As I'm not used to Opensim yet, any advice will be very appreciated.
Thanks