Mobile human interface robot

A mobile robot (100) including a drive system (200) having a forward drive direction (F), a controller (500) in communication with the drive system, and a volumetric point cloud imaging device (450) supported above the drive system and directed to be capable of obtaining a point cloud from a volume of space that includes a floor plane (5) in a direction of movement of the mobile robot. A dead zone sensor (490) has a detection field (492) arranged to detect an object in a volume of space (453) undetectable by the volumetric point cloud imaging device. The controller receives point cloud signals from the imaging device and detection signals from the dead zone sensor and issues drive commands to the drive system based at least in part on the received point cloud and detection signals.