Robots acting in the proximity of humans belong to the most challenging mechatronic systems and attract increasing interest in sciences and in commercial applications. The autonomous wheelchair EASY (electric wheelchair with driver assistance system) is an example of such a system of high autonomy. It is developed in the department of System Dynamics and Control of the Institute of Automation, University of Bremen. This paper gives an overview of the system and its hierarchical control, and presents the modelling and feedback control of two particular sub-problems: the dynamics and trajectory tracking of the wheelchair, and the 3D vision modelling and image-based path control.