The mobility concept of care-O-bot 3

Next generation service robots impose high requirements on the employed mobility concepts. Usage in and manipulation of man-made environments requires high flexibility. The aspect of commercialization puts a limit to available computational performance and acceptable power consumption. Finally, aspects as the robustness on different, changing grounds and uneven terrain have to be considered. This work gives an in-depth view on the omnidirectional, non-holonomic, mobile base of Care-Obot 3. The mechanical structure and the resulting kinematic constraints of the mobile base are addressed. The problem of wheel coordination - intrinsic to the employed kind of mobile base with four steerable standard wheels - and its implications on the applied control method are highlighted. A control scheme - based on a spherical ICM representation - is outlined and the resulting control structure is particularized for the Care-O-bot 3 system