I want the player to become a ragdoll (which I have done) then I want to rotated the arms to cover his head without using animation because animations have 0 give. It’s completely stiff. If I can manually rotate the joints with some kind of “motor” I feel like it would give me the right effect.
Is this what I’m looking for?
This may be solved by using this system AnimFollow
AnimFollow makes a ragdoll follow an animation with the strength you set for each limb. When the character falls you should play an animation that covers the head and does the stuff you want. You can set the strength of the ragdolls individual limbs so that the arms try to cover the head but flex just the right amount. After the fall you can lerp back the strength and continue animate the ragdoll with mecanim.