Passive UHF RFID tags are well matched to robots' needs. Unlike lowfrequency (LF) and
high-frequency (HF) RFID tags, passive UHF RFID tags are readable from across a room,
enabling a mobile robot to efficiently discover and locate them. Using tags' unique IDs, a
semantic database, and RF perception via actuated antennas, this paper shows how a robot
can reliably interact with people and manipulate labeled objects.

LABELING THE WORLD arbitrary associated data. For example, EL-E can use an ID to
access a database with information about the tagged object such as its name and a photo,
actions that EL-E can perform with it, and the actions' icons.• RF perception. By perceiving
the presence and strength of RF signals emanating from a tag, EL-E can estimate its
location. If EL-E detects a tag with its long-range antennas, the tag is likely in the room. If EL-
E detects the tag with its short-range antennas, the tag is likely close to its hand. EL-E's …