Abstract:
An improved radio RFID tag and reader system comprising a reduced scale and scalable vehicle fitted with one or more electronic toll collection RFID tags and a track on which the vehicle may operate at a high rate of speed for long periods of time with minimal friction and without derailing or fatigue to the structure of either vehicle or track. The inventive testing system further utilizes a novel vehicle propulsion system comprising counter-rotating wheels adpated to maintain a variable and accurate speed of the vehicle upon each pass by the reader. The propulsion mechanism propels the vehicle down the track past the reader and returns it to a starting point to provide repeated interaction between RFID tag and reader.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    The present application derives priority from U.S. Provisional Patent Application Ser. No. 62/153,777 filed Apr. 28, 2015. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates generally to RFID tag testing systems and, more specifically, to a system for repeatedly propelling a vehicle around a track to automate the process for testing an electronic toll collection reader and RFID tag system. 
         [0004]    2. Description of the Background 
         [0005]    Radio-frequency identification (RFID) entails the wireless use of radio waves between an RFID tag and a tag reader for the purpose of automatically identifying and tracking an object. The RFID tag includes a RFID tag, capable of receiving a wireless signal, termed an interrogating signal, and responding by emitting an identifying signal unique to the RFID tag. There are a variety of applications for this technology, and RFID tags can be attached to most anything including cash, clothing, merchandise, and can even be implanted in people. One well-known application in the automotive field is in electronic toll collection systems, such as (but not limited to) the E-ZPass™ system used on toll roads in several states in the mid-Atlantic and New England regions. These systems typically comprise one or more readers mounted above one or more toll lanes at the entrance to a toll road, bridge or the like, and emitting a radio signal that is readable by each RFID tag passing underneath in the toll lane. Other electronic toll collection systems utilize one or more readers mounted on or below the travel lane such that vehicles pass over or beside the readers as they travel through the toll plaza. Electronic toll collection systems allow motorists with a RFID tag from an issuing authority to pass through toll stations without making a physical transaction of cash, coins, tickets, etc. and without coming to a complete stop. The toll is paid via a prepaid account or credit card linked to an account, eliminating the need for an exchange of cash or coins. RFID-based toll collection systems have greatly improved the flow of traffic through the toll lanes servicing high traffic toll roads. 
         [0006]    As RFID adoption grows, the need to validate tags for interoperability with readers from other vendors, and vice versa, and for conformance with specified wireless protocol increases. Largely as a result of conformance testing, RFID systems have significantly improved over the past several years. However, the current demand is driving mounting pressure to improve tag performance to achieve read rates closer to 100% at higher speeds, RFID test system designers face a significant challenge when attempting to meet the needs of this emerging market. Comprehensive RFID testing is complex, and entails a combination of conformance, interoperability and lifecycle testing. To be more specific, comprehensive RFID testing may require a testing system capable of moving an RFID tag beneath an antenna array at exactly one hundred miles an hour, a thousand times, followed by repeated at ninety miles an hour, eighty, etc. Thus, any designer of such a test system must provide a level of reliability higher than the tags being tested, yet allow accurate testing the operation of the RFID tag/reader combinations under repeated use at most any vehicle speed over extended (lifecycle) periods of time. 
         [0007]    Accordingly, what is needed is a test system for precisely and reliably testing conformance, interoperability, lifecycle, range and accuracy of RFID tag and reader combinations over an exceedingly high number of passes (i.e., millions) and at precisely-controllable speeds. Moreover, a scalable test system design is needed to allow various types, sizes and numbers of UM tags and readers to be tested under the above conditions. Of course, a system for achieving the above objectives will also be safe for the operator, the vehicle, and the surrounding area. 
       SUMMARY OF THE INVENTION 
       [0008]    Accordingly, it is an object of the present invention to provide an improved apparatus for testing various types of RFID tag and reader combinations especially in the context of electronic toll collection systems, capable of passing the RFID tag within an adjustable range of a reader at an adjustable speed a large number of times, all with extreme accuracy. 
         [0009]    It is also an object of the present invention to provide such a system capable of carrying out the foregoing with cir without operator intervention. 
         [0010]    It is further an object of the present invention to provide such a system that is scalable to allow testing of various sizes of RFID tag and reader combinations and at increasing volumes. 
         [0011]    It is further an object of the present invention to provide a testing system that is safe for the operator, equipment, and surroundings. 
         [0012]    These and other features and benefits are achieved with an improved radio RFID tag and reader system comprising a reduced scale and scalable vehicle fitted with one or more electronic toll collection RFID tags and a track on which the vehicle may operate at a high rate of speed for long periods of time with minimal friction and without derailing or fatigue to the structure of either vehicle or track. The inventive testing system further utilizes a novel vehicle propulsion system comprising a custom designed synchronized motor chive with two or more balanced wheels to maintain a variable and accurate speed of the vehicle upon each pass by the reader. 
         [0013]    For a more complete understanding of the invention. its objects and advantages, refer to the remaining specification and to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    Other objects features and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiment and certain modifications thereof, in which: 
           [0015]      FIG. 1  is a from perspective view of the improved tracked vehicle propulsion system according to the present invention depicting two propulsion systems  200  and one portal  300 . 
           [0016]      FIG. 2  is a side perspective view of the improved tracked vehicle propulsion system according to the present invention depicting two propulsion systems  200  and one portal  300 . 
           [0017]      FIG. 3  is a top perspective view of the improved tracked vehicle propulsion system according to the present invention depicting a vehicle  5  just before it passes through propulsion mechanism  200  at a first end  2   a  of test area  2 . 
           [0018]      FIG. 4  is a side perspective view of the track as in  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0019]    As seen in  FIG. 1 , a comprehensive test system  100  for testing RFID tag/reader combinations according to an embodiment of the invention generally comprises a track  1  forming a closed circuit or loop, most preferably in the shape of an extended oval, and fitted with one or more rotating-wheel propulsion mechanisms  200 . In addition, at least one portal  300  is provided comprising an elevated mount for supporting an RFID reader of antenna directly above the track  1 . A passive moving vehicle  5  rolls and/or slides freely on the track  1 . In a preferred embodiment the moving vehicle  5  is constrained on the track  1  by vertical sidewalls, but one skilled in the art will understand that a slot-car mechanism is also possible as described below. Vehicle  5  is sized as necessary as a matter of design choice to carry one or more electronic toll collection RFID tags  6  being tested. The portal  300  comprises a pair of vertical freestanding legs with a height-adjustable cross-beam mounted there atop for supporting a reader  301 . Although portal  300  is shown as a freestanding mount extending above the travel surface to allow vehicle  5  to pass underneath, it will be understood that a reader  301  or antenna (described further herein) may be positioned at various locations relative to passing vehicle  5 , with or without the need for an accompanying portal  300  mount, based on reader  301  accuracy, the location of RFID tag  6  on vehicle  5 , as will be described, or other considerations. The track  1  is configured with opposing side-walls to define a channel of appropriate size to substantially constrain the vehicle  5  to forward and rearward motion. The preferred propulsion mechanism  200  comprises two counter-rotating wheel assemblies  201 . The wheels  201  are speed-synchronized and may be direct-driven by motors  210  as shown. Motors  210  are preferably high-speed DC brushless motors with integrated speed controllers capable of operating at 4000 rpm with power rating of from 200-700 watts. 
         [0020]    Wheels  201  are mounted such that the space between the peripheries of opposing wheels  201  is slightly less than the width of vehicle  5 . The vehicle  5  is momentarily pinched between the wheels  201  and expelled at a speed ranging between 0-100 mph. The vehicle  5  and portal  300  are designed cooperatively such that the portal  300  mount holds one or more RFID reader(s)  301  each at a measured and preferably-adjustable distance from the one or more RFID tags. In use, the counter-rotating wheels  201  of propulsion mechanisms  200  propel the vehicle  5  around the track  1  at a predetermined speed and, as its RFID tags  6  pass underneath reader  301  at a predetermined distance, the system effectively simulates field use of the RFID tag/reader combination, allowing precise and reliable testing for conformance, interoperability, lifecycle, range and accuracy of the RFID tag and reader combination over months or years of use. 
         [0021]    One skilled in the art should understand that multiple vehicles  5  can be run sequentially on the same track  1 . Similarly, multiple propulsion mechanisms  200  may be provided as shown in  FIG. 1  to reduce or maintain the speed of vehicle  5  around remote portions of the track  1 . Propulsion mechanism(s)  200  control the speed of vehicle(s)  5  as they pass under RFID tag  301  to within accurate increments of 15 mph or less. Propulsion mechanisms  200  are capable of propelling vehicles  5  at speeds of 100 mph or more for as long as testing is desired. Thus, for example, if the total length of track  1  is 0.002 miles (approx. 11 feet), a vehicle  5  traveling at 100 mph is capable of achieving one million test runs of the electronic toll collection RFID tag  6  and reader  301  system in 20 hours. Two vehicles  5  each containing an RFID tag  6  traveling on the same track  1  under the same conditions would be able to achieve the same number of test runs in 10 hours. However, the precise vehicle  5  speed control afforded by the propulsion mechanism(s) also allows accurate testing of the RFID tag  6  and reader  301  system at slower vehicle  5  speeds, such as those suitable for low-speed electronic toll collection systems comprising an array of toll booths and/or machine operated gates. 
         [0022]    With reference to the embodiment shown in  FIGS. 1-2 , track  1  preferably comprises a straight testing area  2  and a return loop section  3  which collectively form the preferably oval loop of track  1 . As shown in  FIGS. 1 and 2 , testing area  2  is preferably one of the two main straightaway sections of track  1 , and propulsion mechanism(s)  200  are mounted proximate the ends of testing area  2 , at least one mechanism  200  at end  2   a  as shown. The testing area  2  of track  1  preferably comprises a flat, elongate-extended floor surface  7  bordered on each long side by a perpendicular sidewall  4  extending upwards from the floor surface. As seen in  FIG. 4 , the height H of sidewalls  4  may be determined as a matter of design preference, but is preferably at least ¼ the height of vehicle  5  so as to constrain vehicle  5  within the track of testing area  2  even when traveling at a high rate of speed. And, as shown in  FIG. 3 , testing area  2  has a width W between sidewalls  4  just slightly wider than the vehicle  5  (described in greater detail below) to prevent vehicle  5  from bouncing between sidewalls  4 , and which further ensures that vehicle  5  will continue on a straight path between propulsion mechanism  200  and mount  300  so that a consistent angle is maintained between reader  301  and RFID tag  6 . 
         [0023]    Portal  300  may be removably or permanently fastened over testing area  2 . Portal  300  preferably comprises two extended support legs  302  mounted perpendicularly relative to the travel surface of test area  2  and joined at the top by transverse member  303  spanning the width of testing area  2  above track  1  and supporting reader  301 . However, other configurations of mount  300  are envisioned. As shown in  FIGS. 1-2  portal mount  300  may be a freestanding member that can be moved into place straddling testing area  2  at various locations along the length thereof. Alternatively, portal  300  may be supported by an attachment to the sidewalls  4  or other portion of testing area  2  with or without a stand allowing portal  300  to rest on the ground beside track  1 . A freestanding or removably affixed portal mount  300  may advantageously alloy the electronic toll collection manufacturer or testing body to adjust the location of reader  301  relative to propulsion mechanism  200  to achieve the desired characteristics of the interaction between RFID tag  6  (not shown) and reader  301 . In use, portal mown  300  is preferably situated in the lengthwise half of testing area  2  proximate second end  2   b.  Optionally, a radar gun  345  or other known tool for measuring the speed of vehicle  5  may be mounted on or near portal mount  300  to measure the speed of vehicle  5  as it passes under portal mount  300 . In addition, any other means of securing reader  301  in the appropriate location to interact with a passing RFID tag  6  may be used without departing from the spirit of the instant invention. For example, reader  301  may be mounted underneath a portion of testing area  2  to capture signals from a RFID tag  6  mounted on the underside of vehicle  5 , at a height above the surface of testing area  2  that is less than the anticipated height of vehicle  5 , and/or may be omitted altogether in favor of a direct attachment of reader  301  to testing area  2 . Where a separate antenna is used to send an interrogating signal to RFID tag  6 , such an antenna is not necessarily mourned adjacent to the RFID reader  301 . 
         [0024]    The propulsion mechanism(s)  200  are designed to propel vehicle  5  from the one end  2   a  to the other end  2   b  end of testing area  2 , or vice versa. Accordingly, vehicle  5  passes through propulsion mechanism  200  and travels down a short length of testing area  2  before passing reader  301 . Track  1  (and specifically, testing area  2 ) is preferably constructed of steel or another hard, smooth material that is able to withstand repeated traffic and apply a minimal amount of friction to test vehicle  5 . This will ensure that vehicle  5  only loses a small amount of speed after leaving propulsion mechanism  200  and before encountering reader  301 . The speed of vehicle  5  as it passes reader  301  can thus be accurately controlled to within only a few miles per hour, or less with the use of a speed measuring radar or like tool mounted proximate reader  301 . 
         [0025]    At the second end  2   b  of testing area  2 , testing area  2  is joined to the return loop  3  portion of track  1 , which completes the loop of track  1  back to the first end  2   a  of testing area  2 . Optionally, as shown in  FIGS. 1-2 , a propulsion system  200  may be mounted at the second end  2   b  of testing area  2  or at one or more locations along return loop  3  for braking, speed reduction and/or to maintain propulsion of the vehicle  5  back around to the first end  2   a  of testing area  2 , where it re-encounters the other propulsion mechanism  200  mounted there for another pass by reader  301 . The loop of track  1  is continuous so that the vehicle  5  motion may remain continuous for unattended operation over days or even weeks. Like testing area  2 , return loop  3  may be formed of a flat surface  8  lined by sidewalls  4 , which may form a continuous loop around the entirety of track  1 . The roadbed  8  may be solid, or, as shown in  FIGS. 1-2 , may be comprised of a plurality of spaced independently-movable rollers  240  mounted to provide a relatively friction-free passage to vehicle  5 . Return loop  3  may take any shape that guides vehicle  5  to turn 360 degrees in traveling back to the first end  2   a  of testing area  2 . Preferably, however, return loop  3  forms a “U” shape at either end of track  1  with a relatively straight portion along the side of track  1  opposite testing area  2  as shown in  FIG. 1 , wherein the “U” shape formed by return loop  3  at either end of track  1  is wide enough to prevent vehicle  5  from flying off of track  1  when propelled at high speeds by propulsion mechanism(s)  200 . The portion of sidewall  4  at the outer edge of each “U” turn of return loop  3  may have an increased height H to prevent this as well. 
         [0026]    Vehicle  5  may be any type of object capable of being propelled by propulsion mechanism  200  and moving in a straight line down testing area  2 , but is preferably a model of a box truck-type vehicle having a roughly rectangular portion to provide a smooth surface to interact with sidewalls  4  mounted on three (3) or more wheels to provide relatively friction-less movement down metal testing area  2 . As an alternative to wheels, vehicle  5  may ride atop low-friction sleds or runners. A rectangular, box-shaped vehicle  5  also provides ample flat surface on which any of the most common types of electronic toll payment RFID tags  6  may be mounted by, i.e., industrial Velcro® or any other (preferably non-permanent) securement means known in the art. 
         [0027]    With reference to  FIG. 3 , in a preferred embodiment, the roadbeds  7 ,  8  of testing area  2  and return loop  3  may instead be formed by two extended flat surfaces mounted side by side within the plane of the roadbed with a slotted gap  9  there between running the length of the track  1 . Slot  9  may be sized to cooperatively engage with a bracket or rod (not shown) on the base of vehicle  5 . By way of example, vehicle  5  may further comprise an extended (1-4″) bar mounted in the center of its underside and extending perpendicularly down from the underside of vehicle  5  such that the rod is captured within slot  9  when vehicle  5  is situated on track  1 . Such a rod should have a diameter slightly less than the width of slot  9  to prevent. any friction from building up between these elements but also to allow the cooperation of slot  9  and the rod to hold vehicle  5  within a straight path along, track  1 . Such rod preferably has a “bulb” or T-shaped bracket on its distal end to prevent the rod from moving vertically up and out of slot  9 . This feature may be removable from the rod, or the rod may be movable from vehicle  5 , to allow vehicle  5  to be removed from track  1  to allow testing with another vehicle. 
         [0028]    As described above, track I further includes one or more propulsion mechanism(s)  200  mounted thereon, at least one such propulsion mechanism  200  being mounted at a first end  2   a  of test area  2  where vehicle  5  begins its trip through test area  2  towards reader  301 . As best shown in  FIG. 3 , propulsion mechanism  200  comprises two mirror image motorized wheels assemblies  201  mounted permanently or removably on either side of track  1 . Wheels  201  are mounted horizontally, parallel to the plane of roadbeds  7 ,  8 , and have an axis of rotation perpendicular to the plane of roadbeds  7 ,  8 , so as to display an angular rotation parallel to the plane of the roadbeds  7 ,  8 . Alternatively, wheels  201  may be mounted vertically, perpendicular to the plane of roadbeds,  7 ,  8 , to propel vehicle  5  through the application of force on both top and bottom of vehicle  5 . Preferably, a motor  210  is mounted below each wheel  201  to provide the proper axis of rotation. Motors  210  may be servo-controlled, pulley drive, or the like provided they are capable of synchronous counter-rotation at the same angular velocity. Alternatively, one motor may be used to provide power to rotate both wheels  201  in synchronization using a serpentine pulley drive. Motors  210  are synchronized so as to provide the same angular velocity to both wheels  201  but in opposite directions. As described above, the two wheels  201  of each propulsion mechanism  200  are preferably mounted on either side of track  1 . The distance between wheels  201  across track  1  is preferably slightly less than the width of vehicle  5  to enable each wheel  201  to come into contact with a side of vehicle  5  as it passes through propulsion mechanism  200 . In an alternative embodiment, where wheels  201  are mounted above and below the passing vehicle  5 , the distance between wheels  201  is preferably slightly less than the height of vehicle  5  to enable each wheel to come into contact with a corresponding horizontal surface of vehicle  5 . Because the system is scalable and designed for use with different types of vehicles  5  carrying different types of electronic toll collection RFID tags  6 , wheels  201  and motor(s)  210  may be mounted on a sliding track perpendicular to the direction of travel of vehicle  5  along test area  2  such that the distance between wheels  201  may be adjusted in a lateral direction (or, where wheels  201  are mounted vertically, in a vertical direction). Where vertically-mounted wheels  201  are used, the upper wheel  201  may also be mourned on an axel outfitted with a spring or other device to allow upper wheel  201  to be forced upward upon the passing of vehicle  5  there beneath, wherein the operation of a spring or other device or the gravity acting on the weight of upper wheel maintains sufficient downward force on upper wheel  201  to allow wheel  201  to apply force to the top of vehicle  5  to project it forward. Such a configuration may thus be adjustable for various vehicles  5  having different heights. Wheels  201  also preferably have a sufficient height at an outer edge thereof to allow contact between the outer edges of wheels  201  and the sides of vehicles  6  of various heights. Thus, wheels may preferably have a height of 1-4 inches at an outer edge thereof. As best seen in  FIG. 4 , wheels  201  preferably extend slightly into and overhang roadway  7 ,  8  to allow contact between the outer edges of wheels  201  and the sides of vehicle  5 , which, as described above, is slightly more narrow than roadbeds  7 ,  8 . To accommodate, this, depending on the height of sidewalls  4 , sidewalls  4  may include a portion of lessened height proximate each wheel  201  as compared to the remainder of sidewalls  4 . 
         [0029]    Wheels  201  preferably comprise a round rubber pneumatic tire  203  mounted to a hub  204 , which in turn may be connected directly or indirectly to the drive mechanisms of motors  210 , The tires preferably utilize a soft-tread design for grip, and are preferably inflated to 20-40 lbs pressure to provide sufficient elasticity to enable them to deform slightly as vehicle  5  passes between them. The friction coefficient between wheels  201  and vehicle  5  should be high to maximize the force with which the angular velocity of wheels  201  will propel vehicle  5  forward, and yet minimize scuffing of the vehicle  5 . The rubber of wheels  201  may be provided with an adherent white coating, or may be fabricated from a white material, such as polyurethane, to preclude any discoloration of the vehicle  5 . The pressure for the two wheels  201  must be maintained at substantially identical and prescribed levels in order to obtain uniform propulsion. 
         [0030]    Alternatively, wheels  201  and/or motor(s)  210  may be mounted on a gimbal to allow wheels  201  to angle slightly towards or away from track  1  so that wheels  201  can spread apart slightly as vehicle  5  passes through and close around the tail end of vehicle  5  to further propel vehicle  5  forward. Vehicle  5  may also have a portion of extended width at a height corresponding to the height of the outer edges of wheels  201  to facilitate a smooth physical interaction between wheels  201  and vehicle  5  as it passes there between. 
         [0031]    When viewed from the back of vehicle  5 , the wheel mounted on the left of vehicle  5  ( 201   a ) is geared to move in a counter-clockwise direction when viewed from the top (above track  1  where vehicle  5  rests) and the wheel mounted on the right of vehicle  5  ( 201   b ) is geared to move in a clockwise direction when viewed from the top. 
         [0032]    Motors  210  preferably comprise sufficient torque to maintain an axial rotation of up to 100 mph in each wheel  201 , and adjustability of same in increments of, at most, 15 mph. Thus, the operator may adjust the speed of vehicle  5  as it proceeds down test area  2  and passes reader  301  by adjusting the speed of motors  210 . In this way, vehicle  5 , carrying one or more RFID tags  6  of the type typically used by electronic toll collection systems, can be caused to pass within range of an reader at variable, controllable speeds. 
         [0033]    Although well suited for use with RFID tags  6  and corresponding readers  301 , it will also be understood that the herein described test system  100  may also advantageously be used to test other types of wireless transmission systems operating as between moving objects. Other useful applications for test system  100  may be found in wireless transmission systems that operate between two or more moving vehicles traveling in proximity to one another, between moving vehicles and infrastructure not limited to electronic toll collection systems, and the like. 
         [0034]    It should now be apparent that the above-described system provides an improved way of testing various types of REID tag and reader combinations by passing the RFID tag within an adjustable range of a reader at an adjustable speed a large number of times, all with extreme accuracy, and without a teed for operator intervention, effectively simulating the operation of an electronic toll collection reader and RFID tag system over months or years of use prior to installing same on an actual toll road. 
         [0035]    Having now fully set forth the preferred embodiments and certain modifications of the concept underlying the present invention, various other embodiments as well as certain variations and modifications of the embodiments herein shown and described will obviously occur to those skilled in the art upon becoming familiar with said underlying concept. It is to be understood, therefore, that the invention may be practiced otherwise than as specifically set forth in the appended claims.