Abstract:
Radio Frequency Identification (RFID) tags are used for automatically determining the connectivity or alignment between physical components, including, for example, connectivity of network cables and device ports, as well as alignment of components assembled by automated manufacturing systems. In one embodiment of the invention, accurate determinations of the physical three-dimensional locations of cables and equipment are employed to determine which cables are plugged into which device ports of which pieces of equipment. In another embodiment of the invention, multiple RFID tags are used to determine the appropriate alignment between components being assembled by an automated manufacturing system.

Description:
FIELD OF THE INVENTION 
   The present invention relates generally to the field of Radio Frequency Identification (RFID) systems and more particularly to the use of RFID tags for determining the connectivity of or the proper alignment (e.g., abutment) between physical components. 
   BACKGROUND OF THE INVENTION 
   The management of complicated networks such as telecommunications networks or sophisticated computer networks is tremendously expensive. A substantial portion of this cost arises from incomplete, incorrect or ambiguous knowledge about a network. For example, a telecommunications network operator may not have an accurate record of how network switches are configured, leading to failed attempts to fix problems or provision new services. This lack of knowledge can in some instances be remedied by polling the networking equipment to determine its actual settings. 
   However, a more fundamental ambiguity arises at the physical level of network cable management. Network cables may be added, removed or moved by support personnel for a variety of reasons, often to solve urgent problems. However, it is very difficult to maintain an accurate record of exactly which cable is connected to what device port of what piece of equipment, since the cables may so easily be connected, disconnected, and reconnected. 
   Typically, network cable locations and connections are tracked manually, by, for example, putting printed tags on each cable, storing the tag-to-cable mappings in a database, and then attempting to manually keep the database up to date. In addition, physical inventories of network offices, in which the cables are identified, tagged and mapped, are themselves typically performed manually. In a large telecommunications or computer network system, it is an extremely expensive proposition to keep track of every cable, where it is, where it runs, and what device port on which piece of equipment it is plugged into. As a result, equipment inventory databases are notoriously inaccurate, and the negative results include, inter alia, loss of network capacity, increased service times and a much greater chance of disruptive service errors. 
   Another problem, seemingly unrelated to the network cable connectivity problem discussed above, involves automated manufacturing systems. Such systems typically involve the automated assembly of components, requiring the attachment of two components (at a time) in a predetermined way. Computer vision systems are often used in such environments to provide feedback from the manufacturing process to the controlling software, thereby allowing the components to be located precisely and correctly in three-dimensional space relative to one another. For example, in an automobile manufacturing facility, if a hood is to be attached to a car body, a computer vision system may be able to determine that the two edges are attached evenly and at the correct distance from one another. Unfortunately however, vision systems are extremely expensive and work only very locally within a limited field of view. In addition, the three-dimensional location information must be indirectly inferred from two-dimensional camera images. 
   Thus, to address both of the above-described problems, it would be highly advantageous if there were an automated mechanism for tracking the precise three-dimensional physical locations of components, from which one could thereby determine the appropriate connectivity or alignment between them. For example, it would be highly desirable to be able to track the physical location of network cables in general, and to be able to identify the connections between cables and equipment device ports in particular. In addition, it would be highly desirable to be able to automatically determine the correct alignment between two components in an automated manufacturing system in a direct manner in a relatively inexpensive way. 
   SUMMARY OF THE INVENTION 
   The present inventor has recognized that Radio Frequency Identification (RFID) tags can be advantageously used to provide a framework for automatically determining the connectivity of or the proper alignment (e.g., abutment) between physical components, including, for example, network cables and devices, as well as components assembled by automated manufacturing systems. As is well known to those skilled in the art, RFD technology allows an object bearing an RFID tag to be located in physical space—for example, it is well known that it can easily be determined that an object bearing an RFID tag is at least “near” an RFID sensing device. This is clearly quite useful in a number of common prior art applications of this technology, such as inventory management in retail and wholesale applications, automatic toll collection, tracking of vehicles, etc. Recently, however, the accuracy with which the location of an RFID tag (and thus the object bearing the RFID tag) can be located in three-dimensional space has improved significantly, which advantageously enables an additional and valuable class of new applications. 
   Specifically, with respect to the network inventory problem described above, for example, the use of RFID tags can be advantageously employed to automatically identify the presence and locations of network resources such as cables and equipment, and with the use of multiple, highly sensitive sensors, the use of such RFID technology can also allow for a real-time determination of the physical locations of these resources in three-dimensional space. In particular, and in accordance with one illustrative embodiment of the present invention however, such accurate determinations of the locations of cables and equipment can be advantageously employed to further determine which cables are connected to (ie., plugged into) which device ports of which pieces of equipment. 
   In addition, with respect to the automated manufacturing system problem described above, the use of multiple RFID tags with highly sensitive sensors can be advantageously employed in accordance with the principles of the present invention to determine the appropriate juxtaposition (e.g., proper alignment and/or abutment) between inventory components being assembled by the automated manufacturing system. Note that the word “juxtaposition” as used herein and in the claims hereof, is intended to encompass both “connectedness,” such as in the case of a cable plugged into a port, as well as “abutment” and “alignment,” such as in the case of two automated assembly system inventory components which are properly positioned and aligned or (Le., “lined up”) for assembly. In other words, as used herein, two components are in “juxtaposition” when they are proximate (ie., near to or touching one other) and spatially coordinated with each other in a predetermined manner. 
   More specifically, in accordance with a first illustrative embodiment of the present invention, one or more reference RFID tags are attached to fixed locations on the faceplate of a network element, and other RFID tags are incorporated into the connectors at the end of each cable. Then, by precisely locating the tag at the end of a cable relative to the reference tag on the element, the exact port into which the cable is plugged (if any) may be advantageously determined. This capability may, for example, be advantageously used to automatically and rapidly conduct a physical inventory of a network. 
   And in accordance with a second illustrative embodiment of the present invention, one or more reference RFID tags are attached to fixed locations on a first inventory component to be assembled, and one or more other RFID tags are attached to a second inventory component to be attached to the first inventory component. Then, by precisely determining the location of each of these RFID tags relative to each other, it can be advantageously determined that the two inventory components have been appropriately connected to each other. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows an illustrative cable and a piece of equipment, each with RFID tags attached thereto in accordance with a first illustrative embodiment of the present invention. 
       FIG. 2  shows a flowchart of the method of the present invention in accordance with the first illustrative embodiment thereof. 
       FIG. 3  shows an illustrative automated manufacturing system environment including a car body and a hood, each with RFID tags attached thereto in accordance with a second illustrative embodiment of the present invention. 
       FIG. 4  shows a flowchart of the method of the present invention in accordance with the second illustrative embodiment thereof. 
   

   DETAILED DESCRIPTION 
   A First Illustrative Embodiment of the Present Invention 
     FIG. 1  shows an illustrative cable and a piece of equipment, each with RFID tags attached thereto in accordance with a first illustrative embodiment of the present invention. The illustrated piece of equipment, device  10 , has three device ports—device port  11 , device port  12  and device port  13 —each with a corresponding RFID tag—namely, tag  14 , tag  15  and tag  16 , respectively—attached to the faceplate of device  10  in very close proximity to the corresponding device ports. In addition, cable  17  has RFID tag  18  attached to cable connector  19  thereof. It will be obvious to those skilled in the RFID art that a number of high precision RFID sensors, which are not explicitly shown in the figure, will necessarily be located in the general vicinity of the components shown in the figure—such as, for example, on the walls of the room in which the components are located—in order to be able to accurately determine the locations of the various RFID tags. 
   Given the environment provided in  FIG. 1 , and in accordance with the principles of the present invention, the precise location in three-dimensional space of cable connector  19  can be determined, as can the precise location in three-dimensional space of each of the three device ports—device port  11 , device port  12  and device port  13 . Then, these determined locations can be advantageously compared to identify whether cable  17  is, in fact, connected to device port  11 , device port  12 , device port  13  or to none of these ports. As can be seen from the figure and as will be determined by the use of the method in accordance with the first illustrative embodiment of the present invention, cable connector  19  is, in fact, in close proximity to device port  12 , and therefore it will be identified that cable  17  is connected to that particular port. 
     FIG. 2  shows a flowchart of the method of the present invention in accordance with the first illustrative embodiment thereof. Note that, in accordance with one illustrative embodiment of the present invention, the illustrative method shown in  FIG. 2  may in particular be used to determine whether a given cable is connected to a given device port. Clearly, it will be obvious to one of ordinary skill in the art that this method can not only be used to verify an anticipated connection between a cable and a device port, but may, alternatively and in accordance with other illustrative embodiments of the present invention, be used iteratively to determine which of a plurality of cables is connected to a given device port, which of a plurality of device ports is connected to a given cable, or, more generally, which ones of a plurality of cables are connected to which ones of a plurality of device ports, to thereby perform a general network cable connection “inventory.” 
   Specifically, the method shown in the flowchart of  FIG. 2  determines whether a given cable is connected to a give device port. First, block  21  checks database  29  to determine the identity (e.g., identification code) of the RFID tag attached to the connector of the given cable. Then, using conventional RFID technology, block  22  determines the precise location in three-dimensional space of the cable connector (ie., of the identified RFID tag). Next, block  23  checks database  29  to determine the identity (e.g., identification code) of the RFID tag attached to the device faceplate next to the given device port. And then, again using conventional RFID technology, block  24  determines the precise location in three-dimensional space of the given device port. Finally, block  25  compares the two determined locations, and, if they are in sufficiently close proximity to each other (as determined by the comparison of decision block  26 ), the connection between the given cable and the given device port is verified in block  27 . Otherwise, the connection does not exist, as reported in block  28 . (Note that it will be clear to those skilled in the art that “sufficiently close proximity” to determine connectivity will depend on the particular application, such as, for example, the distance between neighboring device ports, and will be easily specifiable based thereupon.) 
   In certain alternative illustrative embodiments of the present invention, the relative locations of two RFD tags of interest (e.g., the RFID tag attached to the given cable and the RFID tag attached to the given device port) can be alternatively determined in other well-known ways. For example, in accordance with one illustrative embodiment of the present invention, rather than determining the location of each of these RFID tags and then comparing these locations, an “indirect” approach may be advantageously employed in which a signal is sent simultaneously to both RFID tags which immediately respond thereto, and a time difference is measured between the return signals from each of the tags. (This approach of measuring a time difference in a signal returned from multiple objects is conventional and will be fully familiar to those skilled in the art.) 
   And, in other illustrative embodiments of the present invention, individual RFID tags may not be specifically attached to (e.g. in close proximity to) individual device ports, but rather, one or more RFID tags may be located in fixed positions on the faceplate of the given piece of equipment (ie., the “device”). Then, in accordance with these other illustrative embodiments of the invention, the connectivity of a cable to a given device port may be advantageously determined based on the location of the RFID tag attached to the cable connector relative to the location of the one or more RFID tags attached to the faceplate. That is, rather than determining connectivity based merely on the physical proximity of one RFID tag (ie., the cable connector&#39;s tag) to another (i.e., the device port&#39;s tag), connectivity can instead be determined based on the relative locations of the cable connector&#39;s RFID tag to the one or more RFID tags attached to the faceplate of the device in combination with an a priori knowledge of the fixed location of the device port on the faceplate of the device relative to the fixed locations of the one or more RFID tags attached thereto. 
   With use of the above-described procedure, the connectivity of various cables to various device ports—on one or on a plurality of devices—can be easily determined and/or verified in accordance with one illustrative embodiment of the present invention. Note also that in accordance with another illustrative embodiment of the present invention, by repeatedly sampling these connections (or lack thereof), an automated system can advantageously raise an alarm whenever a cable is unplugged without authorization. Finally, by also incorporating multiple RFID tags at interval lengths along a cable, as well as at a variety of known locations in a building, the physical path of a cable can be traced all the way from its connection to one device port at one end of the cable to its connection to another device port at the other end of the cable, providing substantial value in planning for network upgrades or for construction around cable installations. 
   A Second Illustrative Embodiment of the Present Invention 
     FIG. 3  shows an illustrative automated manufacturing system environment including a car body and a hood, each with RFID tags attached thereto in accordance with a second illustrative embodiment of the present invention. In particular, the figure shows hood  31 , being placed into position on car body  32  by mechanical “arm”  33 . In accordance with the principles of the present invention, hood  31  illustratively includes three RFID tags—tag  34 , tag  35  and tag  36 —each attached thereto and positioned at well-defined and precise locations on the rear of the hood. Similarly, car body  32  illustratively includes three RFID tags—tag  37 , tag  38  and tag  39 —each attached thereto and positioned at well-defined and precise locations on the car body (where the hood is to be attached). Again, it will be obvious to those skilled in the RFID art that a number of high precision RFID sensors, which are not explicitly shown in the figure, will necessarily be located in the general vicinity of the components shown in the figure—such as, for example, on the walls of the room in which the components are located—in order to be able to accurately determine the locations of the various RFID tags. 
   Given the environment provided in  FIG. 3 , and in accordance with the principles of the present invention, the precise location and orientation of both hood  31  and car body  32  can be advantageously determined in three-dimensional space. Then, these locations and orientations can advantageously be compared to determine whether the components are properly attached (or in proper positioning to be attached). As can be seen in the figure, and as will be determined by the use of the method in accordance with the second illustrative embodiment of the present invention, hood  31  and car body  32  are properly positioned for attachment. 
     FIG. 4  shows a flowchart of the method of the present invention in accordance with the second illustrative embodiment thereof. Specifically, the method shown in the flowchart of  FIG. 4  determines whether a first component is in appropriate alignment for connection to a second component. Illustratively, this procedure assumes that each component has a corresponding plurality of RFID tags arranged such that when the components are properly aligned, the corresponding RFID tags are in close proximity to each other. It will be obvious to those skilled in the art that numerous other approaches, all within the spirit and scope of the present invention, can be alternatively employed to verify that two components are in proper alignment for connection to each other (or, in other illustrative embodiments of the present invention, are in fact, properly connected) with use of one or more RFID tags attached thereto. 
   Specifically, in the method shown in  FIG. 4 , block  41  first checks database  49  to determine the number and identity (e.g., identification code) of the RFID tags attached to the first component. For example, with illustrative reference to  FIG. 3 , the first component may be the hood, and the database may indicate that there are three RFID tags which are attached thereto—a rear left corner tag, a rear center tag, and a rear right corner tag—each having a particular identity (e.g., identification code). Then, using conventional RFID technology, block  42  determines the precise location in three-dimensional space of each of these RFID tags, thereby defining the precise location and orientation of the hood. Next, block  43  checks database  49  to determine the number and identity (e.g., identification code) of the corresponding RFID tags attached to the second component. For example, again with illustrative reference to  FIG. 3 , the second component may be the car body, and the database may indicate that there are three RFID tags which are attached thereto—a left corner tag, a center tag, and a right corner tag—each having a particular identity (e.g., identification code). And then, again using conventional RFID technology, block  44  determines the precise location in three-dimensional space of each of these RFID tags, thereby defining the precise location and orientation of the car body. Finally, block  45  compares each of the corresponding pairs of determined RFID tag locations, and, if they are each in sufficiently close proximity to each other (as determined by the comparison of decision block  46 ), the proper alignment between the first component and the second component (e.g., hood and car body) can be confirmed in block  47 . Otherwise, the alignment is not proper, as reported in block  48 . (Note that it will be clear to those skilled in the art that “sufficiently close proximity” to confirm alignment will depend on the particular application, such as, for example, the particular type of components and the means which will be used to assemble them, and will be easily specifiable based thereupon.) 
   As pointed out above, it will be obvious to one skilled in the art that other procedures may be performed to verify correct alignment or connection of components. For example, referring again to the illustrative example of  FIG. 3 , additional RFID tags could advantageously be placed on the front end of the hood (as well as the rear) to ensure a proper orientation of the hood in the vertical dimension. In addition, similar procedures may be used to detect assembly line problems by, for example, noticing when a component is off of its desired location. And finally, if the precise three-dimensional locations of the RFID tags can be determined quickly enough, such procedures can advantageously be used directly to guide the actual movement of the manufacturing robot itself. 
   Addendum to the Detailed Description 
   It should be noted that all of the preceding discussion merely illustrates the general principles of the invention. It will be appreciated that those skilled in the art will be able to devise various other arrangements, which, although not explicitly described or shown herein, embody the principles of the invention, and are included within its spirit and scope. Furthermore, all examples and conditional language recited herein are principally intended expressly to be only for pedagogical purposes to aid the reader in understanding the principles of the invention and the concepts contributed by the inventors to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. It is also intended that such equivalents include both currently known equivalents as well as equivalents developed in the future—i.e., any elements developed that perform the same function, regardless of structure. 
   Thus, for example, it will be appreciated by those skilled in the art that any flow charts, flow diagrams, state transition diagrams, pseudocode, and the like represent various processes which may be substantially represented in computer readable medium and so executed by a computer or processor, whether or not such computer or processor is explicitly shown. Thus, the blocks shown, for example, in such flowcharts may be understood as potentially representing physical elements, which may, for example, be expressed in the instant claims as means for specifying particular functions such as are described in the flowchart blocks. Moreover, such flowchart blocks may also be understood as representing physical signals or stored physical data, which may, for example, be comprised in such aforementioned computer readable medium such as disc or semiconductor storage devices.