CA2471781A1 - A grommet rfid asset tracking system - Google Patents

Abstract

A grommet RFID asset tracking system for tracking containers, trolleys, pulleys, bins, pallets, casing, chassis, cans and other similar structures used to aid the transport of products of various kinds.

Description

IV
TECHNICAL FIELD
The present invention relates to radio frequency identification (RFID) systems for products tracking, and in some embodiments to such systems for use in tracking 15 containers, trolleys, pulleys and bins.
BACKGROUND OF THE INVENTION
20 Containers are very reliable means for products transportation since they allow for efficient product storage and packaging at very low maintenance cost. They can be easily moved and can be loaded with products ranging from luxurious cars to cartons containing millions of steel washers from the manufacturing industry.
They exist in various dimensions and are widely used worldwide. Millions of containers 25 can be located in harbors around the globe waiting to be emptied from their content or to be filled with new goods and shipped to the other end of the world.
Traditional identification systems or tracking methods for containers include hand written numbers (usually written on the very metallic surface of the containers) or bar-code identifications plates attached to the containers. The first approach 30 greatly suffers the deterioration of the hand written numbers due to acid rains,

2 scratches on the metallic surface or highly corrosive substances the container may come in contact with in its environment. While providing a slight improvement over the first approach, the second approach mandatory requires a line of sight between the bar-code scanner and the bar-code plate attached to the container;
a requirement that cannot always be met in all circumstances. Furthermore, hard environmental conditions such as snow, mud or dust may prevent seamless reading of bar-code information.
Radio frequency identification devices (RFID's) are commonly utilized for electronically identifying objects. In a typical configuration, they include an integrated circuit that is coupled to an antenna. They may have a battery or may instead obtain energy from an external reader. RFID devices without battery may be preferred for applications in which lower cost is a dominant factor meanwhile RFID devices with battery may be preferred for application in which longer range is required. Either or both may be used in conjunction with the present invention. The integrated circuit associated with an RFID device includes a certain amount of memory which stores the unique identifier of the device and other information related either to the tag itself or to the application the tag is used in. In an exemplary application, the RFID tag is attached to the object to be identified. An interrogator provides through its antennas a carrier signal which power's stimulates the tag and causes a signal to be transmitted from the tag to the reader (the interrogator). The signal comprises data which identifies the object associated with the tag. The data identifier or any other information obtained by the reader may then be compared to entries in a database of identifiers or to any information associated with that RFID tag. Doing this way, information regarding a tagged item may be obtained, updated, and provided to a user, andlor written to an RFID
tag in a very efficient way. It is to be noted that no line-of-sigh between the reader and the tag is required for successful reading of the information contained in the tag.
Further, environmental conditions like rain, dust, snow or mud have no impact on the accuracy of the interrogation process. Successful item interrogation only

3 depends on the antennas loops of the interrogator and is also an aspect of this invention.
Various patents and publications describing the use of RFID tags in conjunction with pallets trolleys or bins have been introduced in the past years. Among these, [5] describes an asset tracking system with the interrogation of RFID-tagged pallets by a forklift equipped with one or more RFID reader antennas. No specific statement is provided on how to attach the RFID tags to the pallets. In [3]
and [4]
Forster et al. introduced a handle that encompasses an identification chip.
The RFID tag is tightly coupled to the handle whose shape in turn highly depends on the geometry of the container it is attached to. In [7], a tag identification system is provided for monitoring and tracking transport of meat in a packing plant. The system is used in conjunction with trolleys systems. The major limitation of the system described in this publication is twofold. First of all, the code used by this system is defined by a unique pattern of holes. This approach is essentially vulnerable to the usual debris and dust of packing houses. Secondly, the code is not detachable from the trolley arm and consequently hard to change or to upgrade.
The common limitation of the systems described above is their poor portability in terms of technology and location. In the case of the tag attached to the container handle, a container redesign dictated by storage constraints, requires a tag package redesign. The hole-pattern approach for example is hard to implement when the items to be tracked are small. Further, in all the methods introduced above, mounting the tags to the devices to be tracked is rather cumbersome and sometime requires highly specialized equipment and/or technicians. To the knowledge of the authors, no universal RFID system wherein the tags can be easily attached to the tracked items and which can be used in many different areas ranging from container tracking to packing plant meat control has been presented so far.

4 In an identification system comprising millions of items to be identified, the identification devices should be quickly mounted to the items (i.e. the containers).
Costs would be excessive and outweigh the benefits of the identification system if each device was timely to mount to the containers. Inherent with the quick attachment, the devices should be mounted in a straightforward manner that is not overly difficult to require specialized equipment, or highly trained technicians during the attachment process. In addition, the identification tag should securely attach to the item. This should prevent the tag from inadvertently falling off even when the item may be dropped, bounced around and otherwise roughly handled.
By providing the means for secure and reliable attachment of identifiers to items to be tracked and by combining the aforementioned with RFID technology into an efficient RFID asset tracking system, the current invention aims to solve the problems stated earlier and hence, is adequate to the identification and tracking of hundreds and even thousands of small containers located in offices or warehouses and big containers located in harbors as well as to the identification of beef, pork or Iamb carcasses and meat pieces in packing houses.
SUMMARY OF THE INVENTION
Grommet RFID tact The present invention presents a tracking system and an embodiment thereof in which the unique identifier of the tracked item is attached to the said item by the means of a fastener and a ruggedized tag. Actually, the integrated circuit containing the data together with the antenna are molded or laminated into a plastic material such as santoprene or any similar material. The inlay is reinforced with a high tensile product such as epoxy or hard nylon. A spindle shape terminates the molded device. This spindle allows for easy insertion into holes of any given diameter and also provides a lock mechanism once inserted. This realization of an identifier can be securely attached to any surface.

Identification Svstem The other aspect of the invention relates to the electronic identification of the parts originating from a common source as for example the meat pieces that originate from a common carcass in a slaughterhouse. Usually the animal carcass is

5 associated with an initial tag that uniquely identifies the animal. However after the carcass is split into two or more parts, there is the urgent need to further identify the parts newly created while preserving their relationship to the original animal carcass. The present invention solves this problem with two different approaches.
The first approach introduces a parent-child relationship in the memory of the integrated circuit of the tags and by dividing the meat processing plant into logical pipeline stages which convey the parental information as the meat parts are processed in the pipeline.
In the second approach, single root information is added to the part identifier of each newly created part. This root information which is essentially the identifier of the original carcass is broadcasted to the single processing units which this time are loosely coupled. The advantage of this approach is that only one single piece of information needs to be broadcasted to the units. However, the parent child relationship between the single meats pieces is not given any more. Further a new carcass cannot enter the system prior to completion of processing of the previous carcass.
In the two approaches the single meat processing units may be connected to one another using a legacy RS232, or RS485 serial line, an Internet connection, a WIFI connection or any other adequate transmission medium and protocol.
Antennas arrangement for the identification system Another aspect of the present invention pertains to an antenna arrangement that maximizes the read/write accuracy of the system, The goal is to be able to read 100 % of the tags passing through the antenna's field. This arrangement consist of a so called active antenna loop connected to the processor and an passive antenna loop which should be as parallel as possible to the active antenna [8].
BRIEF DESCRIPTION OF THE DRAWINGS
~ Figure 1 depicts a 3 dimensional view of the described grommet RF(D tag.
The spindle is visible in foreground.
~ Figure 2 depicts the grommet with the molded tag inside. Part of Figure 2 also shows how the grommet can be mounted to any plane surface such as a wall.
~ Figure 3 is a sectional view of the grommet with the chip inside.
~ Figure 4 shows the chip antenna of a typical grommet chip. Part of the picture also shows how the grommet described here can be mounted on a container.
~ Figure 5 shows the memory organization of a chip that is to be used in the case of a parent-child relationship identification system.
~ Figure 6 shows the memory organization of chip that is to be used in the case of a root-leaf relationship identification system.
~ Figure 7 is the typical antenna arrangement for the identification described here. It consists of:
o A reader or interrogator, o An active antenna o A passive antenna ~ Figure 8 depicts a typical processing plant that can be used in a slaughterhouse. The processing plant consist of processing nodes that in turn consist of traditional slaughterhouse accessories and mandatory antenna arrangement as the one depicted in Figure 7.

DETAILED DESCRIPTION OF THE INVENTION
RFID Grommet This aspect of the present invention presents an RFID tracking system and an embodiment thereof in which the unique identifier of the tracked item (the tag) is attached to the said item by the means of a fastener. The fastener comprises two parts: The first part 100 which actually bears the integrated circuit and the second part 104 which acts as a lock for the system. The chip 107 containing identification data is molded or laminated into the tag bearer 100 which may be a plastic material such as santoprene or any similar material. A spindle shape 102 terminates the molded device. This spindle allows for easy insertion into holes 103 of any given geometric shape and also provides the channel through which the lock mechanism goes. The cross section of the part of the spindle attached to the bearer should preferably be greater than the cross section of the part that is to be inserted into the hole. The lock mechanism 104 consists of a plastic rod (which may be a cylinder or of other geometric shape) whose two ends the head 109 and the tail 110 are shaped to allow for optimal attachment of the tag to the item once the rod is inserted into the spindle. The tail 110 of the rod may be circular or of any other geometric shape but the surface of the tail should be much greater than the surface of the geometric figure defined by the hole through which the rod is inserted. The head 109 which is mushroom shaped easily goes through the hole of the spindle when inserted from one side but then expands itself once it reaches the other end of the spindle such as to prevent the rod from being removed from the spindle by drawing it back. The present invention poses no restriction upon the lengths 113 or the sectional dimensions 113 of the rod and the spindle. The said identifier can be securely attached to a container, to a trolley, or to any surface or portion of surface into which a hole can be drilled.
When used in conjunction with a container 108, the identifier should preferably be attached to the container according to 101 from which it results that the identifier will be located inside the container. Doing this way will significantly help shielding the identification tag from damage while being handled.
RFID Identification System with the antennas arrangement RFID Identification System This aspect of the invention relates to an electronic identification system.
The said system is used for reliable identification of parts originating from a common source as for example the meat pieces that originate from a common carcass in a slaughterhouse.
Prior solutions for tracking units originating from a common source include among others, physically associating a first transponder to the common source and then splitting the common source into three or more units and subsequently associating a second transponder to one of the parts whereby the code of the second transponder is electrically associated with an identifier of the common source. A
variant of this approach consists in physically associating a first transponder with the common source and then splitting the source into at least two first units and one or more of the units is physically separated from the first transponder after such splitting. One or more second transponders are physically associated with at least one of the first units that were physically separated from the first transponder by splitting. The codes of the second transponders are electrically associated with the identifiers of the first transponder.
The common limitation of the aforementioned approaches is the fact that they do not provide a mechanism that efficiently links the source information to the derived units. Since the code of the transponders of the derived units is simply electrically associated to the identifier of the first transponder, counterfeiting the origin of a unit by a simple manipulation of the associated transponder code is very easy and cannot be detected if the performed manipulation is done keeping some criteria in mind. Further, the codes of the associated transponders of the unit parts do not carry any information on their origin. Since this link information is missing, backtracking of the origin of a given unit is substantially hard and cumbersome.
In the respective RFID tags, the unique identifiers are stored in a read-only non volatile memory area, hence modification of these identifiers is assumed to be absolutely impossible without partial or total destruction of the tag.
However, application data such as the potential parent information which is written in the field is normally stored in a read/write memory area that can be easily modified.
Ensuring the authenticity of such information is the key for a flawless identification system .
The present invention proposes the use of a cryptographic keyed hash function to uniquely link the identifier code of the source (stored in the read/write memory area) to the unique identifier of the derived units (stored in a read-only area).
Doing this way, any modification to the stored value of the source identifier will be easily detected. Consequently, the source identifier and the identifier of the derived units are definitely bound to one another. This approach efficiently counters any attempt to modify or falsify the origin of a given unit. Further backtracking the origin of the unit is also significantly simplified since the required information is directly stored in the memory of the item.
~ As depicted in Figure 5, in the case of a direct parent-child relationship between the source and the derived unit, the identifier of the parent is stored in the memory of the child unit. Further, a hash value of the child's unique identifier, stored with the parent identifier and a system master key is also stored in memory.
~ In the case of a root-leaf relationship, where the root identifier should never be stored in clear text in the memory of the leaf RFID tag, the root identifier is stored to the a keyed hash value of the leaf identifier and the system's master key before being stored in memory. Further, a keyed hash value of the root identifier is also stored in leaf tag's memory (see Figure 6). To verify the authenticity of the origin, the verifier first computes the keyed hash value of the leaf identifier and uses this value to recover a potential root identifier value. Further, using this value and the system's master key, 5 the verifier computes the keyed hash value of the potential root identifier and compares this value against the value stored in the leaf memory.
In both cases, any hash function such as MDS, SHA-2 or RIPEMD can be used.
10 The antennas arrangement Figure 8 depicts a typical arrangement for the realization of the identification system presented herein. Each of the processing elements consists of a traditional meat processing element such as cutting accessories and a mandatory antenna arrangement as depicted in Figure 7. The antenna arrangement consists of a reader or interrogator together with an active antenna and a mirror. Adding a mirror to an active antenna to increase the read/write range of the interrogation is peculiar to the system presented here. The processing nodes are connected to one another in accordance with the type of relationship (parent-child or root-leaf) that the system implements. In a root-leaf relationship, the root identifier is broadcasted to all the leaf nodes that depend on the given root. In a parent-child relationship, instead, the parent identifier is only forwarded to the nodes that reside immediately after the considered node in the processing direction. If the processing system is viewed as a pipeline and functions as such the parent-child relationship should be preferred since it allows for simple sequencing of the processing steps. It is the duty of each processing node to attach a unique identifier to any unit that is generated within the node. This ensures that each new identifier will contain the correct source information and that each unit that reaches the end of the work bench will carry the correct information. If a unit arrives at a processing node and is not split before leaving the node, no additional identifier should be added to the unit.

Although the present invention has been explained hereinabove by way of a preferred embodiment thereof, it should be pointed out that any modifications to this preferred embodiment within the scope of the appended claims is not deemed to alter or change the nature and scope of the present invention.
References [1] US Pat N. 6,520,544 B1 Mitchell et al. Radio Frequency Labels on Reusable Containers.
[2] US Pat N.6,483,434 B1 Hans Umiker, Container Tracking System. [3] US Pat N. 6,469,627 B1 Forster et al. Mounting Clip Having a Wireless Communication Device.
[4] US Pat N. 6,580,357 B1 Forster et al. Handle Tag for Identification of a Container.
[5] US Pat N. 6,669,089 B2 Cybulski et al. Radio Frequency Identification Systems For Asset Tracking.

[6] US Pat N. 6,545,604 B1 Dando et al. Methods For Electronic Tracking of Units Originating From A Common Source And Assemblies Comprising Transponders Attached To Meat Spikes.

[7] W09836645 Boatner et al. Trolley Identification System.

[8] US Pat N. 6,703,935 Chung et ai. Antenna Arrangement for RFID Smart Tags

Claims