Care-O-bot® is the product vision of a mobile robot assistant to actively support humans in domestic environments. The meanwhile fourth generation of this successful development series is more agile and modular than its predecessors and offers various ways of interaction. It also stands out through the use of cost-reducing construction principles. In this way, large parts of its internal construction feature folding sheet metal, which is economical to produce in small quantities. The enhanced agility of Care-O-bot 4 is owed to the patented spherical joints around discreet pivot points on its neck and hips. They extend the robot’s working space and allow 360 degree rotations of head and torso. Based on its modular system design, the fields of application for Care-O-bot 4 are wide-ranging. While the concept for the Care-O-bot 3 was a more reserved, cautious butler, its successor is as courteous, friendly, and affable as a gentleman.