Adaptive walking pattern generation and balance control of the passenger-carrying biped robot, HUBO FX-1, for variable passenger weights

A passenger-carrying biped robot is a practical robot capable of carrying a passenger for both entertainment purposes and disabled transport by means of biped walking. In the walking controls of the biped walking robot, changes in the payload are not generally considered. However, in the case of a passenger-carrying biped robot, the range of possible payloads for passenger weight is relatively wide, from zero to approximately one hundred kgf. In the authors' previous research pertaining to passenger-carrying biped robots, the robot was modeled using a specific passenger weight; hence, the control parameters were tuned for it and kept to be constant. However, the previous method's weakness was a decrease in the walking performance and walking stability of the robot when the passenger's weight was much heavier or lighter than the predefined passenger weight. Therefore, in this paper, the walking pattern generation and balance control methods are developed to adaptively cope with variable passenger weights. These methods are then experimentally verified to ensure that the walking performance could be preserved uniformly for a variation of passenger weights.