Stability maintenance of a humanoid robot under disturbance with fictitious zero-moment point (FZMP)

The goal of the project SFB588 supported by the Deutsche Forschungs-gemeinschaft (DFG) is to generate concepts, methods and a concrete prototype of a humanoid robot. The intended application area is, for instance, a generic kitchen, where the robot is planed to perform actions autonomously at the user's request. In this paper, a model of stable analysis of a humanoid robot is given, in which the different environments are considered. By introducing a concept of fictitious zero-moment (FZMP), a method to maintain the whole body stability of robot under disturbance is presented. The support polygon and the rotation edge in the case of losing balance are determined by means of simulation. In order to maintain stability in different environments a new control strategy is presented including the adjustment of the support polygon, the push or pull support of hand with environment, the movement of upper robot body. The relative position between FZMP and support polygon is specially emphasized. The feasibility of the proposed method is demonstrated through the simulation.