Aethon Adds RFID to Robotic Hospital Helpers

A Tug might be called upon to pick up a specimen on a particular floor, in a specified patient room. After it arrives, a nurse presses a red stop button on the robot and places the specimen inside its carrier, then pushes a green button, instructing the Tug to deliver the sample to the lab.

In addition, a Homer or Tug retrofitted with an RFID reader can be dispatched to a given floor or unit to collect tag data, enabling the Aethon software to generate an inventory of the area. Seiff says Aethon's asset-location software, running on the automaton's computer, determines the location of each tag sensed by its onboard RFID interrogator. It accomplishes this task using a proprietary algorithm to calculate the time it takes for a tag's RF signal traveling to reach the reader's antenna, while ascertaining the interrogator's location based on the robot's internal mapping function. The software pulls the signal data from the reader when the machine is at least three different distances from the tag. "The software might take one reading at 20 feet away," he explains, "then another 10 feet away and one 2 feet from the tag." Seiff says the software can determine the tag's location to an accuracy of approximately 3 feet.

A Homer or retrofitted Tug stores the location data of all the tags it reads throughout its "shift," then uploads this information to the main Tug OS software, running on a dedicated server at the hospital. This software is also used to send delivery commands to the robot, or to update its set route around the hospital. If the hospital has a Wi-Fi network, however, the robot sends the location data in real time to this server—or, if the facility has only partial Wi-Fi coverage, then it transmits its tag data as soon as it's within Wi-Fi range.

Although Aethon does not have an exclusive relationship with any single RFID hardware provider, Seiff says, all hospitals evaluating the RFID asset-tracking component of the Tug and Homer offerings are employing active UHF tags and readers manufactured by Identec Solutions. Seiff notes that Aethon customers can chose to retrofit their Tugs already in use with RFID interrogators and antennas, or to purchase the Homer robots, then pay a monthly fee for each tag used. Thus, they don't need to pay the full price of each tag in addition to the licensing cost of the Aethon location software.

For example, if a hospital decides to track 100 assets, they might pay $500 per month ($5 per tag) to have all tagged assets tracked. Maintenance of the tags and software, as well as the license to use the software, would be included in this price.

"We're getting a lot of interest from hospitals that are already using RFID to track assets in their operating or emergency rooms, but don't want to pay to install a reader infrastructure throughout their entire hospitals," says Seiff. "By using Homer or adding readers to their Tugs, they don't need to worry about shutting down rooms in order to install readers. And if they change the location of departments within the hospital down the line, they won't have to also move the reader infrastructure."