Balance Walking

[Samane Amini]

Hi friends
Recently, I was wondering if I can actuate lower limb joints to drive skeletal model. In fact, I tried to drive the skeletal human body by forward dynamic in closed loop. Now I want to know that the human model could be balanced only by lower limb joints(hip-knee-ankle )?
In detailed, the joints of skeletal human body (hip-knee-ankle) are derived by a controller and finally the skeletal model walk with maintaining upright balance? What problems this issue could be have?