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Method for RFIDs to track movement and automate safety-related warning systems for movable factory equipment

IP.com Disclosure Number: IPCOM000125472D
Publication Date: 2005-Jun-02
Document File: 5 page(s) / 71K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for radio frequency identifiers (RFIDs) to track movement and automate safety-related warning systems for movable factory equipment. Benefits include improved functionality, improved safety, and improved cost effectiveness.

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Method for RFIDs to track movement and automate safety-related warning systems for movable factory equipment

Disclosed is a method for radio frequency identifiers (RFIDs) to track movement and automate safety-related warning systems for movable factory equipment. Benefits include improved functionality, improved safety, and improved cost effectiveness.

Background

      On movable factory equipment, such as wafer carts and forklifts, the operator is required to manually sound a warning when driving through pedestrian-occupied areas. An automated solution is required to improve pedestrian safety.

              Global positioning systems (GPS) and sonar are candidates as solutions for locating movable factory equipment. However, each has associated problems. GPS cannot work in shielded buildings due to satellite signals not being able to penetrate the shielding. Sonar can detect when other objects are coming into proximity but has difficulty differentiating fixed position, such as walls and furniture, and moving objects, such as people. Another hindrance to these technologies may be the price.

      An RFID transmitter/receiver (reader) interrogates an RFID chip (tag or transponder) by transmitting a radio frequency (RF) signal that is intended to stimulate the tag. In response, the chip returns an electromagnetic field with a signal of a specific frequency modulation related to its own identification number. The response frequency is translated by the reader into a specific number, uniquely identifying that specific tag. A 4-digit hexadecimal RFID system can respond with 65,535 (“0000” - “FFFF”) different ID numbers. An 8-digit system has more than 4 billion combinations. These numbers directly determine the number of independent tags that can be used in the system.

 

      Readers can receive transponder response signals simultaneously within the interrogation zone. As a result, multiple tags can occupy the same or near location relative to the reader and the reader can read all tags within that region.

      Reduced energy consumption of an RFID reader translates directly to a reduction in the RF field generated and the power of the resulting RFID signal returned by a passive tag. Passive RFID tags use field energy and do not require an external electrical connection. Active RFID tags and readers use external electricity. For the most efficient use of onboard, battery powered RFID readers, a balance must be achieved between the number of affixed tags with their path locations and the field output of the readers.

      RFIDs can operate at varying frequencies, including UHF (225-400 MHz) and higher, 2.45, 5 and 13.56 GHz.

General description

      The disclosed method uses an RFID transmitter/detector device (reader) affixed to a moving piece of factory equipment. The reader emits an RF field and detects RFID chip signals when the moving equipment brings the reader’s emitted field within the proximity of a...