The CENTAUROB is a mobile service robot which can operate in unstructured environments while always remain in a statically stable position. The special feature of this system is the use of two Stewart platforms as leg structures, providing high flexibility and maneuverability. By a special foot geometry (shape like a C), it has been possible for the first time to realize a walking biped which can even handle spiral staircases. In this paper, we present a new and advanced prototype of this system.