This work is about the design, implementation and testing of an autonomous charging system for a three wheel drive service robot. The purpose is to find a way to autonomously drive the robot from a position close to the charging station towards the station itself. This was one subsection of an autonomous driving project from California State University, Los Angeles. At the beginning a research about the state of the art of this technology has been presented together with references to relative works and papers. The introduction also includes a comparison among the different charging systems employed for market and custom service robots and an overview of the different docking algorithm strategies.