Described are the motivation and a method for combining readings of RFID tags placed in static locations in a plant environment using a mobile reader attached to a forklift and inertial measurements of the motion of the forklift to track its position and ultimately the positions of containers it moves within the plant. Strengths and limitations of RFID-based and inertial-based methods are presented along with an algorithm for postprocessing and combining the readings of each. The accuracy of the resulting position estimates are shown to be on the same order as the accuracy of RFID reader range variation. Presented here is an effective method of indoor localization of forklift vehicles equipped with mobile RFID readers. The method is based on the fusion of inertial measurements with information from static RFID location tags. While each individual method alone is prone to substantial errors, fusion of the two can provide results of reasonable quality while minimizing the cost of implementation. The accuracy of the resulting location estimate depends on the spacing of the location tags throughout the plant as well as the variability of the RFID reader detection range. In practice it is possible to achieve an accuracy within 5-7 feet which is acceptable for the stamping plant problem. The ultimate goal of this development is to determine and record the locations of the RFID tagged containers handled by a given forklift. Specifically, the described approach has been developed to track the rack locations for automotive stamping plants. While this paper has focused on the fusion of the inertial measurements with the static information from the RFID tag locations for the purpose of tracking the delivery vehicle, it should be noted that the full material tracking problem is more complex. In addition to location awareness, the pick-up and delivery event with its associated inventory must be identified by monitoring the stream of RFID tag readings seen by the mobile reader. This must be accomplished robustly despite delivery complexities such as moving stacks of racks where not all of the moved racks will be seen by the reader during the entirety of the delivery event.
Integration of mobile RFID and inertial measurement for indoor tracking of forklifts moving containers
Integration von mobilen RFID und Inertialmessung für die Verfolgung von Container transportierenden Gabelstaplern innerhalb von Gebäuden
2009
10 Seiten, 3 Bilder, 16 Quellen
Aufsatz (Konferenz)
Englisch
MOTOR DRIVING DEVICE FOR ELECTRIC FORKLIFTS AND FORKLIFTS USING SAME
Europäisches Patentamt | 2015
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