There are enhancements neccessary in the foot to deal with un-even ground. The small model relies on a level surface for balance. Tables and floors provide this easily. On a large model that will be presented in parking lots, grass fields, and the like, an ability to sense and compensate for bumps and holes is neccessary. The sketch shows sensors located around the foot in opposing pairs. The feedback from these opposing pairs of pressure sensors drive actuators in the ankle to move the x,y orientation until all the sensors read the same stress, balancing the weight on the foot no matter the terrain. This would be an active sense and respond loop that updated continuously.