Comment by imtringued

Inverse kinematics are piss easy.

When grasping an object you need to know the normal force on the contact point of the object and check that you're still in the friction cone.

This is hard, because you need to know the friction coefficient of the object and finger tip combination, you need to know the exact coordinates on the object you're putting that finger plus the orientation and graspable surfaces of the object and you have an imperfect model of the robot dynamics that doesn't account for friction or the dynamics of the manipulated objects.

Basically nothing is easy. You don't know anything about what you're manipulating.