The goal of this thesis is the development of an autonomous navigation system for a mobile robot named Paquitop. Its main peculiarity is to achieve omnidirectional motion exploiting conventional wheels. The Paquitop platform has been designed and prototyped by the researches at Politecnico di Torino during the last two years. This work represents the first step to enable the robot with autonomous navigation capability to perform indoor assistive tasks in full autonomy. The software architecture is designed to fulfill the following tasks: Mapping, Localization, Obstacle Avoidance and Path Planning. The first step for the design is the definition of a Hybrid Control Architecture based on the primitive functions Sense-Plan-Act.