Abstract:
Methods and systems for a monitoring system for a vehicle are provided. The system includes at least one radio frequency identification (RFID) system comprising at least one transceiver and a plurality of RFID tags, the tags coupled to a plurality of vehicle components, a plurality of vehicle component retaining assemblies coupled to the plurality of components and operatively configured to substantially shield the amount of radio frequency (RF) energy received from the transceiver by each tag in a first position and unshield each tag in a second position, and an alert system for receiving information regarding the plurality of vehicle components and for generating an alert based on the information received.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application claims the priority of U.S. Provisional Patent Application No. 60/719,318 entitled “System and Method for Conditional Door Latch and Sensor Status Using Radio Frequency Identification” filed Sep. 21, 2005, which is hereby incorporated by reference in its entirety. 

   BACKGROUND OF THE INVENTION 
   This invention relates generally to radio frequency identification (RFID) systems, and more particularly, to systems and methods for monitoring components using RFID systems. 
   Component monitoring for transportation vehicles, for example, airplanes, is essential to ensure safety, security, and operational readiness. At least some airlines rely on personnel to physically inspect doors, latches, and containers to verify their status and location. However, relying on the skill level of the inspector may result in errors and/or the expenditure of significant man hours. Currently, life vests can be detected on the airplane by attaching an RFID tag onto the vest. By this method, an RFID reader can detect the plurality of life vests on the airplane, and by counting, can determine that all required vests are on the plane. This does not determine that all vests are properly stowed, as stolen items placed in passengers&#39; baggage are still detected. Further, numerous signals are received from all the RID tags attached to all the various types of equipment present, and the desired signals may be difficult to differentiate. 
   Currently, life vest tampering can be detected by placing a frangible RFID tag on the life vest pocket, such that removing the life vest destroys the RFID tag. Again, an RFID reader can detect the life vests on the airplane, and can, by counting, verify that all the required vests are present and not tampered with. In this case, a hand-held short range RFID tag reader can be used to find the tampered life vest pocket by looking for the absence of an RFID response from the tampered seat group. The stolen vest cannot be detected at all, and the problem of multiple signals remains. 
   Other airlines rely on elaborate system of wired sensors positioned throughout the airplane. Each door, latch, and component may be wired to visually or audibly to notify flight personnel regarding their status. However, wired systems add weight and complexity to the design of airplanes. 
   BRIEF DESCRIPTION OF THE INVENTION 
   In one embodiment, a system for monitoring a vehicle includes at least one radio frequency identification (RFID) system comprising at least one transceiver and a plurality of RFID tags, the tags coupled to a plurality of vehicle components, a plurality of vehicle component retaining assemblies coupled to the plurality of components and operatively configured to substantially shield the amount of radio frequency (RF) energy received from the transceiver by each tag in a first position and unshield each tag in a second position, and an alert system for receiving information regarding the plurality of vehicle components and for generating an alert based on the information received. 
   In another embodiment, a method for monitoring vehicle components includes coupling at least one RFID tag to at least one vehicle component, coupling at least one RFID transceiver configured to emit an RF energy within the vehicle to the at least one tag, shielding an amount of RF energy received by the at least one tag such that the at least one tag can not transmit to the at least one transceiver, and coupling an alert system for receiving information from the at least one transceiver. 
   In yet another embodiment, a monitoring system for a plurality of airplane components includes a radio frequency identification (RFID) system comprising at least one of a RFID tag and a RFID transceiver, each positioned within a fuselage of the airplane, said tag coupled to at least one of an airplane component, and at least one radio frequency (RF) energy shield extending circumferentially around said at least one RFID tag such that RF energy directed from said RFID transceiver is blocked or detuned when said at least one RF energy shield is in a first position. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic side view of an exemplary fuselage of an aircraft  10  in accordance with an embodiment of the present invention; 
       FIG. 2  is a perspective view of a portion of the RFID component status monitoring system shown in  FIG. 1  that may be used to monitor a lavatory area; 
       FIG. 3  is a perspective view of an exemplary latch that may be used with the lavatory area portion of the system shown in  FIG. 2 ; 
       FIG. 4  is a perspective view of a portion of the RFID component status monitoring system shown in  FIG. 1  that may be used to monitor a galley area; 
       FIG. 5  is a perspective view of an exemplary latch that may be used with the galley area portion of system shown in  FIG. 4 ; and 
       FIG. 6  is a perspective view of an exemplary RFID enabled tag that may be used with the various embodiments of the system shown in  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   As used herein a shield refers to an object configured to interrupt, obstruct, or otherwise degrade or limit the effective performance of an RFID transponder assembly. Although many objects are capable of interrupting, obstructing, or otherwise degrading or limiting the effective performance of an RFID transponder assemblies, only items configured to perform this function are referred to as sheilds. 
   Many specific details of certain embodiments of the invention are set forth in the following description in order to provide a thorough understanding of such embodiments. One skilled in the art, however, will understand that the present invention may have additional embodiments, or that the present invention may be practiced without several of the details described in the following description. 
     FIG. 1  is a schematic side view of an exemplary fuselage of an aircraft  10  in accordance with an embodiment of the present invention. Aircraft  10  includes an RFID component status monitoring system  12  that includes at least one RFID reader  14  positioned at a predetermined corresponding number of locations within aircraft  10 . Typically such locations are a lavatory area  16  and a galley area  18 . Additional readers  14  may be positioned at further locations depending upon the monitoring needs of a particular aircraft model or other type of vehicle. A plurality of aircraft access doors  20  includes respective latches  22  for maintaining access door closed and sealed during a flight. RFID component status monitoring system  12  includes an alert system  24  for receiving information regarding a plurality of vehicle components, for example, but not limited to, access doors  20 , latches  22 , and stowable components such as life jackets, and other personnel protective equipment, and for generating an alert based on the information received. 
     FIG. 2  is a perspective view of a portion of RFID component status monitoring system  12  (shown in  FIG. 1 ) that may be used to monitor lavatory area  16 . In the exemplary embodiment, system  12  is configured to monitor an aircraft door latch status. Although  FIG. 2  illustrates system  12  in the context of lavatory doors and latches, it is to be understood that the present invention is a system and method for reporting door, cabinet, and food cart latch status over a wireless link to the airplane avionics, eliminating the complex wiring and sensors used in traditional implementations providing a reduction in system complexity, wiring and weight. 
   In addition, some door latches are linked to signs indicating the status or condition of the door. System  12  includes a plurality of RFID tags  102 ,  104 , each coupled to a respective door  106 ,  108  of a lavatory  110 ,  112 . System  12  also includes RFID antennas  116 ,  114 , and RFID reader  14  that are complementary to RFID tags  102 ,  104 . In the exemplary embodiment, system  12  monitors a door latch status of each latch on a respective lavatory door  106 ,  108 . The latch status drives occupied/unoccupied signage on an aircraft and also provides an indication to the aircraft avionics for situational awareness for both pilots and flight attendants. RFID reader  14  is located proximate to lavatory area  16  to be monitored. In the exemplary embodiment, RFID readers  14  are placed above the ceiling panels  118  and reader antennas  114  and  116  are incorporated into ceiling panels  118 , under carpet  120 , and/or into the laminate used on the monuments to be monitored. Because reader antennas  114 ,  116  are able to be manufactured out of etched metal, copper tape, or thin wire; they can easily be incorporated into the space between a floor panel  122  and carpet  120 , and onto the backside of ceiling panels  118  or decorative laminates used on most monuments. 
     FIG. 3  is a perspective view of an exemplary latch  300  that may be used with the lavatory area  16  portion of system  12  (shown in  FIG. 2 ). Latch  300  includes a bolt portion  302  configured to engage a slot (not shown) in a jamb (not shown) of door  106 ,  108 . Bolt portion  302  is positioned within door  106 ,  108  adjacent a peripheral edge of door  106 ,  108 . Bolt portion  302  is coupled to a knob  304  extending away from bolt portion  302  such that bolt  302  is actuated through a slot  306  in an inside surface of door  106 ,  108 . 
   Bolt  302  includes a shield  307  extending from a side of bolt  302 . Shield  307  blocks RF energy in the frequencies used by RFID tag  102 ,  104 , for example, by creating a faraday cage. In another embodiment, shield  307  detunes the RFID tag antenna sufficiently to prevent normal function. Moreover, shield  307  may be formed from an RF-opaque material, for example, carbon fiber. Bolt  302  is translatable between a first unlatched position  308  and a second latched position  310 . An RFID enabled component such as an RFID tag  102 ,  104  is coupled to door  106 ,  108  proximate latch  300  and in alignment with a path of shield  307  as bolt  302  is moved between first position  308  and second position  310 . 
   In the exemplary embodiment, lavatory latch status is read without the traditional wiring and door contact sensors using RFID tag  102 ,  104  and shield  307 . RFID tag  102 ,  104  is located adjacent the latch  300  such that tag  102 ,  104  is uncovered when bolt  302  is in position  308  and covered when bolt  302  is in position  310 . Such configuration permits tag  102 ,  104  to receive enough energy to transmit only when RFID tag  102 ,  104  is in unlatched position  308 . 
   An optional second RFID tag  314  is coupled to door  106 ,  108  proximate latch  300  and in alignment with a path of shield  307  as bolt  302  is moved between second position  310  and first position  308 . The RFID tags transmit different codes such that system  12  recognizes the position of bolt  302  from the received code. 
     FIG. 4  is a perspective view of a portion  400  of RFID component status monitoring system  12  (shown in  FIG. 1 ) that may be used to monitor galley area  18 . The galley area portion of system  12  includes a reader  402  mounted between an interior panel  404  and the skin  406  of aircraft  10 . System  12  also includes one or more reader antenna  408 , which may be positioned above interior panel  404  and/or under carpet  410 . 
     FIG. 5  is a perspective view of an exemplary latch  500  that may be used with the galley area  18  portion of system  12  (shown in  FIG. 4 ). Food carts and cabinet latch status for galley area  18  is monitored using a galley area portion of system  12  that is substantially similar to the lavatory area portion of system  12  (shown in  FIG. 2 ). In the exemplary embodiment, a standard food cart latch  500  includes a rotatable bolt  504  coupled to a knob  506  is used. An RFID enabled component such as an RFID tag  508  is coupled to a food cart  510  in a position where RFID tag  508  is uncovered by bolt  504  when bolt  504  is in a first unlatched position  508  and is covered by bolt  504  when bolt  504  is in a second latched position  510 . In the exemplary embodiment, RFID tag  508  comprises a peel and stick substrate that is adhesively coupled to food cart  510 . In various alternative embodiments, a shield plate is coupled to an edge of a door, such that an associated RFID tag is shielded or detuned when the door is in the closed position, and exposed to an RFID reader when the door is in the open position. 
   System  12  is also configured to detect a missing component such as a line replaceable unit (LRU), by placing a shield plate onto the edge of the LRU mounting tray, such that the RFID tag is shielded or detuned when the LRU is present, and exposed to an RFID reader when the LRU is removed or incompletely installed. 
   In an alternative embodiment, an unfastened seat belt can be detected if an RFID tag is placed in the one half of the buckle such that the RFID tag is shielded when the two halves of the buckle are joined together. 
     FIG. 6  is a perspective view of an exemplary RFID enabled tag  600  that may be used with the various embodiments of system  12  described above. In the exemplary embodiment, RFID enabled tag  600  includes a substrate  602 . An RFID device  604  is coupled to a surface  605  of substrate  602 . In an alternative embodiment, device  604  is coupled to a recess  606  formed in surface  605  of substrate  602 . In another alternative embodiment, device  604  is embedded in an interior of substrate  602 . RFID enabled tag  600  also includes a shield  608  coupled to surface  605 . Shield  608  shields or detunes RFID device  604  from an RFID reader (not shown). In the exemplary embodiment, shield  608  is formed of a metallic foil that is weakly coupled to surface  605  using an adhesive  610  such that a pulling or shearing action between shield  608  and surface  605  would separate them and expose RFID device  604  to an RFID reader. 
   In another alternative embodiment, an improperly stowed device or missing device can be detected, such as a missing life preserver, fire extinguisher, life raft or other device by attaching an RFID tag to the carrying tray for the device, and a foil metal shield onto the device being protected. As described above, the RFID tag is shielded or detuned when the equipment is properly stowed, and exposed to an RFID tag reader when removed. Accordingly, system  12  permits an instantaneous high confidence test of the presence of life vests on the aircraft prior to an overseas flight, thus reducing aircraft turn time. 
   For removable or frequently stolen equipment like life vests, it may be desirable to attach the RFID tag to the equipment, and the shield onto the carrier. With this alternate method, a wide range RFID reader within the cabin detects the theft, and a hand held short range RFID reader detects the stolen equipment, wherever it has been hidden. 
   In an alternative embodiment, system  12  is configured detect exposure to solvents or water. For example, by manufacturing RFID tag  600  with adhesive  610  configured to de-bond and permit shield  608  to peel away from substrate  602  in the presence of the solvent or water, thereby exposing RFID device  604  to detection by a reader. 
   In another alternative embodiment, system  12  is configured detect exposure to high temperatures. For example, by manufacturing RFID tag  600  with adhesive  610  configured to de-bond and permit shield  608  to peel away from substrate  602  in the presence of high temperatures, thereby exposing RFID device  604  to detection by a reader. 
   The performance of the above described embodiments can be aided by the use of disbond promoters, which react with heat or solvents to push apart the two layers of substrate  602  and shield  608 . For example, a heat-sensing disbond promoter includes water filled microspheres that burst when the temperature rises above a predetermined range. At least some known materials become brittle, or liberate gas when exposed to radiation. 
   In still another alternative embodiment such materials are used to form an RFID shield that disbonds after exposure to a predetermined dose of radiation. At least some known materials lose structural integrity when corroded. In yet another alternative embodiment such materials are used to form an RFID shield that is sensitive to corrosion. 
   In another embodiment, a mass is attached to shield  608  such that a mechanical shock or vibration above a predetermined level is detected by the shield disbonds above a certain acceleration rate. Such a device is particularly useful for detecting improper handling of sensitive equipment during shipping. 
   In another embodiment, a reusable heat detector includes a bimetallic strip configured to couple shield  608  to substrate  602  such that shield  608  is moved away from substrate  602  outside a predetermined temperature range, and moved back to a position covering substrate  602  and RFID device  604  when the temperature returns to the predetermined temperature range. 
   In another embodiment, a reusable pressure detector includes a gas-filled mechanism configured to couple shield  608  to substrate  602  such that shield  608  is moved away from substrate  602  outside a predetermined pressure range, and moved back to a position covering substrate  602  and RFID device  604  when the pressure returns to the predetermined pressure range. 
   The foregoing description of the exemplary embodiments of the invention are described for the purposes of illustration and are not intended to be exhaustive or limiting to the precise embodiments disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not with this detailed description, but rather by the claims appended hereto. 
   The above-described methods and systems for identifying aircraft component parts and for mistake proof aircraft maintenance is cost-effective and highly reliable. The system permits monitoring of a plurality of vehicle components without using costly and heavy hard-wired monitoring systems. Accordingly, the methods and systems described herein facilitate operation of vehicles including aircraft in a cost-effective and reliable manner. 
   Exemplary embodiments of systems for identifying aircraft component parts and for mistake proof aircraft maintenance are described above in detail. The components of these systems are not limited to the specific embodiments described herein, but rather, components of each system may be utilized independently and separately from other components described herein. Each components of each system can also be used in combination with other component identifying systems. 
   While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.