RU2793212C2 - Method and system for reading/writing data from/to rfid tags integrated/applied to/on tires transported on conveyor belts - Google Patents

Abstract

FIELD: automotive industry.

SUBSTANCE: each tire (4, A, B, C) is provided with a corresponding RFID tag (5, 5A, 5B, 5C) storing a unique identifier of the indicated tire (4, A, B, C). The method comprises the following: an antenna (2) installed above or next to the conveyor belt (3) and configured to radiate radio frequency signals towards the coverage area (21) on the conveyor belt (3) and receive backscattered radio frequency signals from this area (21) coverage; and a reader (6) connected to the antenna (2) to control the latter during transmission and reception. The method includes applying an innovative pre-calibration step to the reader (6) and then performing a read and/or write stage while the calibrated reader (6) is operating.

EFFECT: increase in the performance of reading, detecting RFID tags.

9 cl, 6 dwg

Description

The field of technology to which the invention belongs

The present invention relates to a method and system for reading data from radio frequency identification (RFID) tags and/or writing data to RFID tags integrated/embedded or applied to/on tires transported on conveyor belts.

State of the art

There is a need in the tire industry for solutions that automatically and uniquely identify tires during production, use and disposal.

For example, with specific reference to tire production, automatic and unambiguous identification of tires allows you to optimize production processes and logistics operations, increase the use of automated control systems, perform efficient tire tracking / tracing, and therefore create smart tire enterprises.

In this context, it is known to use barcodes printed on tires to manage tire production and create a production history for individual tires. However, this solution has its limitations, as the printed barcodes can be removed or damaged during the production and/or normal use of the tires, making them illegible or, in any case, difficult to read.

To address such limitations, US 2016/0092814 A1 proposes using a tire identification system based on radio frequency identification (RFID) tags. In particular, US 2016/0092814 A1 discloses a tire manufacturing management system using RFID tags, the operation of which includes: attaching an RFID tag to a tire prior to manufacturing a finished tire in tire manufacturing processes; recognizing a tire label attached to the tire in each of the manufacturing processes; and thus managing the information according to the manufacturing process for the individual tire. The tire manufacturing management system according to US 2016/0092814 A1 includes an attachment portion of an RFID tag; many RFID readers; a plurality of control terminals for respective processes; tire batch management server; and a tire production management server. US 2016/0092814 A1 also describes code recognition of an RFID tag affixed to a tire transported on a conveyor belt, wherein the code recognition is performed by an RFID reader adjacent to said conveyor belt.

In addition, Italian Patent Application No. 102016000009727 discloses a configurable and customizable wireless RF sensing device that can be successfully integrated/incorporated into or applied to a tire to provide automatic identification of a tire during its manufacture, during logistics operations, as well as during during its normal operation. In addition, the configurable and customizable RF wireless sensor device of document 102016000009727 can conveniently be configured to also provide diagnostic data such as temperature or pressure data.

WO2016095922 discloses a method for handling and processing tires in a tire manufacturing facility. The method includes positioning the uncured tire in a support and moving the support with the tire in a conveyor system.

Document DE202017102186 discloses a pneumatic tire with an inner surface defining a cavity and with an outer surface facing away from the inner surface; wherein the bus contains a radio chip having an antenna, and the radio chip is configured to work with electromagnetic waves, and electromagnetic waves have a wavelength; while the antenna along its entire length is located at a distance from the outer surface, which on average is less than 1/10 of the wavelength and/or less than 25 mm.

EP 1792685 discloses a method and apparatus for identifying 3D coordinates of a target area on a tire, the method including: taking a digital image of the tire; finding a tire bead edge using pixel brightness values from the tire image; calculating a center and a radius of a tire bead circumference using a plurality of image pixels on a tire bead edge; and performing a pixel brightness search on the tire bead circumference using the center and radius of the tire bead circumference to determine the X, Y coordinates of the target area. The z-coordinate and slope of the target zone are determined by several point-to-point distance calculations over the entire area.

The essence of the invention

The Applicant has conducted in-depth research to develop an improved method and system for reading and/or writing data from/to RFID tags integrated/embedded or applied to/in tires transported on conveyor belts, thereby offering the present invention.

Thus, it is an object of the invention to provide a method and system of the type mentioned above, providing, in general, excellent RFID-based read/write performance, and in particular, unambiguous detection of RFID tags with improved performance over currently known solutions.

This problem is solved by the present invention, as it relates to a method and system for reading and/or writing data from/to radio frequency identification (RFID) tags of tires transported on a conveyor belt, as defined in the attached claims.

More specifically, the present invention relates to a method for reading and/or writing data from/to RFID tags of tires transported on a conveyor belt in the direction of transport, each tire being provided with a corresponding RFID tag storing a unique identification of said tire. Said method comprises providing:

• an antenna installed above or next to the conveyor belt and configured to:

- emitting radio frequency (RF) signals towards the coverage area on the conveyor belt, and

- receiving backscattered RF signals from said coverage area; And

• a reader connected to the antenna to control the latter during transmission and reception.

The method also comprises performing a pre-calibration step including calibrating the reader by:

a1) placing a given tire provided with a given RFID tag on a conveyor belt and holding said given tire stationary under/next to the antenna;

a2) as long as the tire is kept stationary under/next to the antenna,

- determining the minimum transmit power required to activate a given RFID tag,

- determining a calibration transmit power higher than the minimum transmit power mentioned, and

- emitting, through the antenna, calibration RF signals with said calibration transmit power and receiving, through said antenna, backscattered calibration RF signals from the given RFID tag;

a3) while continuing to emit calibration RF signals and receive backscattered calibration RF signals, gradually move the given tire back and forth on the conveyor belt until the given RFID tag stops responding;

a4) estimates of the size of the coverage area in the direction parallel to the direction of transport, based on operation a3);

a5) measurements

- the first received power levels of the calibration RF signals received by the given RFID tag when the given tire remains stationary under/next to the antenna and when said given tire moves back and forth, and

- second received power levels of the backscattered calibration RF signals received by the reader via the antenna when the given bus remains stationary under/next to the antenna and when said given bus is moved back and forth;

a6) repeating operations a1)-a5) with different tires, thereby obtaining

- a plurality of calibration transmit powers related to different buses,

- a set of estimated coverage sizes related to different tires, and

- a set of first and second levels of received power related to different tires; And

a7) calculations

- the average transmit power based on the received calibration transmit powers,

- the average size of the coverage area based on the estimated sizes obtained,

- polling frequency based on the average size of the coverage area and the given conveyor belt speed,

- average received power levels based on the received first and second received power levels, and

- one or more thresholds based on average received power levels.

Moreover, the method further comprises performing a read and/or write step that includes operating the calibrated reader to:

b1) emitting, via the antenna, one or more RF interrogation signals with the average transmit power and the interrogation rate calculated in the pre-calibration step;

b2) receiving, via an antenna, one or more backscattered RF interrogation signals from an RF tag of a bus passing through the coverage area, wherein one or more of said backscattered RF interrogation signals bear a unique identifier of the transported bus;

b3) measurements

- one or more thirds of the received power levels of the RF interrogation signal(s) received by the RFID tag of the transported tire, and

- one or more fourth received power levels of one or more backscattered RF interrogation signals received by the reader via the antenna;

b4) detecting a transportable tire by comparing the third and fourth received power levels with the threshold(s) calculated(s) in the pre-calibration step; And

b5) identifying the detected transport bus based on a unique identifier carried by one or more backscattered RF interrogation signals.

For convenience, the step of reading and/or writing includes the operation of a calibrated reader to also:

b6) reading and/or writing data related to the tire from/to the RFID tag of the transported tire.

Preferably, the antenna is configured to have a radiation pattern that would result in a coverage area covering:

• the entire width of the conveyor belt in the direction perpendicular to the direction of transport; And

• a limited length in a direction parallel to said transport direction.

For convenience, the antenna is flat, parallel to the conveyor belt, and has a given length in a direction parallel to the conveying direction and a given width in a direction perpendicular to said conveying direction, the given length being greater than the given width.

Preferably, the first, second, third, and fourth received power levels are indicative of amplitude and phase measurements of the received power.

In addition, the present invention also relates to a system for reading and/or writing data from/to RFID tags of tires transported on a conveyor belt in the direction of transport, each tire being provided with a corresponding RFID tag storing the unique identifier of said tire. Said system contains:

• an antenna mounted above or next to the conveyor belt and configured to

- emitting RF signals towards the coverage area on the conveyor belt, and

- receiving backscattered RF signals from said coverage area; And

• a reader which is connected to the antenna in order to control the latter in transmitting and receiving and is intended to perform the pre-calibration step and, after calibration, can perform the reading and/or writing step of the above method according to the present invention.

Preferably, the system comprises a plurality of antennas that:

• installed in different positions along the conveyor belt;

• made, each separately, with the possibility of emitting RF signals in the direction of the corresponding coverage area on the conveyor belt and receiving backscattered RF signals from it; And

• connected to the reader with the ability to operate in transmission and reception modes;

where the position of each detected tire is determined by the reader or ECU connected to it or integrated/built into it, based on the antenna (for convenience, based on the position of the antenna) that received the backscattered one or more RF interrogation signals from which it was detected said tire.

Brief description of the drawings

For a better understanding of the present invention, preferred embodiments, which are intended solely as non-limiting examples, will now be described with reference to the accompanying drawings (all not to scale), in which:

Figure 1 schematically shows an RFID gateway according to a preferred (albeit non-limiting) embodiment of the present invention;

figures 2, 3 and 4 show an example of the antenna pattern of the RFID gateway shown in figure 1;

Fig. 5 schematically shows an example script for pre-calibrating the RFID gateway shown in Fig. 1; And

FIG. 6 schematically shows an example of detecting a sequence of three buses passing through the RFID gateway shown in FIG.

Detailed description of the invention

The following discussion is provided to enable a person skilled in the art to make and use the present invention. Various modifications of the embodiments shown and described will be apparent to those skilled in the art without departing from the scope of the present invention as stated herein. Thus, the present invention is not intended to be limited to the embodiments shown and described, but is intended to provide the broadest scope of protection consistent with the principles and features disclosed herein and defined in the appended claims.

The present invention relates to the use of one or more RFID reading and/or writing systems (hereinafter referred to as RFID gateway(s)) installed along the path of a conveyor belt to monitor tires transported on said conveyor belt and installed, each individually, with a corresponding An RFID tag that stores data related to the tire, including a unique tire identifier and, for convenience, also additional information (for example, information elements indicating the tire model, date and / or place of production, materials used for the manufacture of tires, etc.) .

The present invention can advantageously be used for automatic control, monitoring and tracking applications in (smart) tire manufacturing, sorting and recycling plants that use conveyor belts. In fact, using the present invention, it is possible to deploy RFID gateways along the paths of conveyor belts to control/monitor/track tires moving on said conveyor belts, and RFID gateways, when used, read data that is related to tires and is stored on RFID tags of transported tires , and may also write (i.e., store) data on them (eg, unique identifiers and/or, as previously explained, also additional information) for convenience if desired.

In particular, when using an RFID gateway according to the present invention, it is possible to uniquely and individually identify each transported tire, avoiding the problem of multiple reads from adjacent tires/conveyors. This allows you to automatically perform certain actions with each individual transported tire and unambiguously monitor / control the sequence of transported tires.

For a better understanding of the present invention, FIG. 1 schematically shows an RFID gateway (generally referred to as 1) according to a preferred (albeit non-limiting) embodiment of the present invention.

Specifically, the RFID gateway 1 includes an antenna 2 (usually an antenna array) positioned above a conveyor belt 3 transporting tires 4 along (i.e. parallel to) a predetermined transport direction, each tire 4 being provided with a corresponding RFID tag (FIG. 1 not shown) storing the (at least) unique identifier of said tire 4.

The antenna 2 is essentially flat and parallel to the conveyor belt 3 and the xy reference plane defined by:

• the first reference direction x, parallel to the given direction of transport of the tires 4 on the conveyor belt 3; And

• a second reference direction y perpendicular to the first reference direction x (and therefore also orthogonal to said predetermined transport direction).

Antenna 2 has a given length L along the first reference direction x (i.e. parallel to it) and a given width W along the second reference direction y (i.e. parallel to it), where the given length L is greater than the given width W (i.e. L>W)

The antenna 2 is located at a predetermined distance D from the conveyor belt 3 along (ie, parallel to) a third reference direction orthogonal to the first and second reference directions x and y.

Preferably, to facilitate detection of transported tires 4, antenna 2 is a directional antenna configured to emit and receive radio frequency (RF) signals to/from a coverage area covering:

• the entire width of the conveyor belt 3 along the second reference direction y (that is, parallel to it); And

• a limited length along (ie, parallel to) the first reference direction x.

For convenience, the antenna 2 is a directional antenna configured to have a blade-shaped radiation pattern that is oriented orthogonally with respect to a given direction of transport of the tires 4 on the conveyor belt 3 (that is, perpendicular to the first reference direction x and parallel to the second reference direction y). ) and which has a main lobe spanning the entire width of the conveyor belt 3 along the second bearing direction y and a limited length along the first bearing direction x.

In this regard, FIGS. 2, 3, and 4 show an example of a radiation pattern for an antenna 2, respectively, in the xyz base space, the xz base plane, and the xy base plane (the RFID tag applied to the tire 4 shown in FIG. 3 and 4 marked pos.5).

For convenience, antenna 2 is configured to emit/receive RF signals having frequencies in the ultra high frequency (UHF, UHF) range, preferably in the 860-960 MHz frequency range, more preferably in the 865-868 MHz subband and/or in the frequency subband 902 -928 MHz.

In addition, additional requirements for Antenna 2 may include:

• gain above 0 dB;

• work on the basis of circular polarization;

• Beam width less than 90° in at least one plane.

Referring again to FIG. 1, the RFID gateway 1 further includes a reader and/or writer unit/device 6 (hereinafter simply referred to as a reader for brevity) connected to the antenna 2 in a wired manner, for example with a coaxial cable. Moreover, a control and processing unit 7 (for example, a computer) is locally or remotely connected to the reader 6 to control its operation. In this regard, it should be noted that the processing and control unit 7 can also be integrated/embedded in the reader 6 for convenience.

For convenience, the reader 6 may be connected to a plurality of antennas 2 installed at different positions along the path of the conveyor belt 3. time/power sharing strategies are adopted).

In addition, optional requirements for the reader 6 may conveniently include:

• support for the entire frequency range of 860-960 MHz, or the aforementioned frequency subranges;

• ability to support multiple antenna connections and operate up to +31.5 dBm;

• Ability to work with separate read and write levels and command-adjustable power, eg from 5 dBm to 31.5 dBm with an accuracy of at least +/- 0.5 dBm.

In view of the above, in use where the tires 4 are transported on the conveyor belt 3, the RFID gateway 1 can uniquely detect and automatically identify each tire 4 passing under the antenna 2. Therefore, a command/control system using a plurality of RFID gateways 1 (and /or a plurality of antennas 2 connected to one or more readers 6) installed along the path of the conveyor belt 3 (or along the paths of multiple conveyor belts 3) can accurately determine the location of each moving tire 4.

In addition, with the convenient use of proper processing of transmitted and received RF signals (amplitude, phase and time), it is also possible to monitor/monitor the sequence of buses 4 passing through one/each RFID gateway 1 (or, in the case of multiple antennas 2, connected to one or more readers 6, a series of tires 4 passing under each antenna 2).

Moreover, each reader 6 for convenience can be configured to:

• reading, in addition to unique tire identifiers, also additional data related to tires that are stored on RFID tags 5 of transported tires 4 (for example, data on information elements indicating the tire model, date and/or place of production, materials used for manufacturing tires, etc.); And

• if necessary, also recording (that is, saving) data on RFID tags 5 of transported tires 4.

In this regard, it should be noted that, as is clear, one/each reader 6 can be used for convenience to record also unique identifiers on RFID tags 5.

Read and/or write operations can be conveniently controlled by:

• a control and processing unit 7 connected to all used readers 6, said control and processing unit 7 being configured (particularly programmed) to selectively control each reader 6 to perform one or more respective predetermined reads and/or writes; or

• a central control unit remotely connected to all used processing and control units 7, said central control unit being configured (in particular programmed) to selectively control each processing and control unit 7 in order to cause the latter to selectively control each reader 6, connected to it to perform one or more corresponding specified read and/or write operations.

More generally, a method for reading and/or writing data from/to RFID tags 5 of tires 4 transported on a conveyor belt 3 according to a preferred embodiment of the present invention includes:

• a pre-calibration step including the calibration of the reader 6, wherein said pre-calibration step is conveniently performed immediately after the installation of the RFID Gateway 1 or in case the environment undergoes significant changes that may affect the RF communication scenario (for example, changes in the positions of scattering objects) ; And

• the stage of reading and/or writing, performed using a calibrated reader 6.

In the following, a preferred (albeit non-limiting) embodiment of said method will be described in detail with specific reference to the RFID gateway 1, namely in the case of one single antenna 2, one single reader 6 and one single processing and control unit 7, it being clear that the following ideas of the invention can be applied mutatis mutandis to various system architectures, including the use of one or more processing and control units 7, each connected to one or more readers 6, each connected to one or more antennas 2 (which for convenience can be have a different spatial arrangement with respect to the conveyor belt, for example, can be located near / close to its edge).

Preferably, the detection of the RFID tag is based on the combined use of the power amplitude and phase of the RF signals transmitted by the reader 6 through the antenna 2 to the RFID tag 5 and backscattered from the latter into the antenna 2 and hence received by the reader 6.

For convenience, some preliminary operations may be common to both the pre-calibration step and the read and/or write step, for example:

• connecting the reader 6 to the processing and control unit 7 by selecting the appropriate communication port/interface (eg Ethernet, serial interface, USB, Wi-Fi, etc.);

• select reader 6 (if multiple readers 6 are used) and switch on its antenna 2 (or its antenna 2 if multiple antennas 2 are connected to one/each reader 6);

• Definition of specific polling methods in terms of operating frequency, polling rate (that is, the number of polls per second (or other unit of time)) and radiated power.

For convenience, at the beginning of the communication between the reader and the tag, the reader 6 activates the RFID tag 5 passing under the antenna 2 by sending a continuous signal. The activated RFID tag 5 then receives commands from the reader 6 and finally sends back data (i.e. a unique identifier and/or additional data associated with the bus) by modulating the backscattered continuous signal received from the RFID gateway 1. Backscattered powers and transmitted signals are measured using received signal strength indicators (RSSI) on the reader side (RSSI _R , in amplitude and phase) and on the side of the RFID tag (RSSI _T , in amplitude and phase).

For a better understanding of the pre-calibration step, a preferred (albeit non-limiting) embodiment thereof will be described in detail below.

In this regard, figure 5 schematically shows an example of a scenario for performing pre-calibration of the reader 6.

In particular, as shown in FIG. 5, the tire 41 provided with the RFID tag 51 is conveniently placed on the conveyor belt 3 directly below the antenna 2, and the minimum power (P _min ) that the reader 6 must emit through the antenna 2 to activate the RFID -mark 51, is determined in a convenient way (preferably by performing a power measurement procedure at power on).

Further, the transmission power value P _TX = P _min + P _sm , where P _sm denotes a safety margin (e.g., 3 dB), is conveniently set to ensure sufficiently reliable communication between the reader 6 and the RFID tag 51 regardless of the position of the RFID tag. marks 51 in/on rail 41 (polar orientation).

Said transmit power P _TX is then used to transmit RF signals from antenna 2, while RSSI values are measured both on the side of the RFID tag and on the side of the reader (RSSI _T , RSSI _R ) both in amplitude/modulus and in phase.

Then the size of the coverage area 21 of the antenna 2 on the conveyor belt 3 (i.e. the area in which there is a maximum probability that the RFID tag 51 will be detected) can be experimentally determined by gradually moving the tire 41 back and forth (manually or using a conveyor belt 3) from the starting position until the RFID tag 51 stops responding. In this regard, it should be noted that the size of the coverage area usually depends on the particular configuration used (eg, transmit power P _TX , antenna beamwidth, type of conveyor belt, etc.).

In order to reduce the multiple responses from the RFID tags 51, 52, 53 of adjacent tires 41, 42, 43, the adjacent tires 41, 42, 43 on the conveyor belt 3 can be suitably spaced for convenience so that only one tire 41/42/43 is present at a time. within a certain coverage area 21 (e.g., assuming that the reading volume 22 has an approximately ellipsoidal shape, the minimum distance d _min between adjacent tires 41, 42, 43 can be taken more conveniently than the semi-major axis a _x /2 of the coverage area 21, parallel to the conveying direction of the tires 41, 42, 43 on the conveyor belt 3).

For more information on RFID tags, refer to, for example, G. Casati et al., “The Interrogation Footprint of RFID-UAV: Electromagnetic Modeling and Experimentations”, IEEE Journal of Radio Frequency Identification, Volume 1, Issue 2, pages 155-162, 25 October 2017.

For convenience, to account for tuning variability, the above procedure is repeated N times (for example, at least three times) with different buses 41, 42, 43 to determine the average transmit power P _TX-av , average RSSI RSSI _T-av , RSSI _R-av (amplitude and phase) and the average size of the coverage area 21.

Thus, at the end of the pre-calibration step, the transmit power value that will be used to perform the read and/or write step is set to P _TX-av , while the average values of RSSI RSSI _T-av , RSSI _R-av are used to set one or multiple thresholds to be used to detect transported tires and to distinguish between/among multiple readings (eg due to insufficient tire spacing, multiple tires on adjacent conveyor belts, random multipath phenomena, etc.).

Various threshold calculations can be conveniently adopted based on the average RSSI RSSI _T-av , RSSI _R-av and depending on various factors such as the particular configuration used (i.e. transmit power P _TX , antenna beamwidth, type of pipeline tapes, etc.). For example, you can calculate:

• one common threshold value to be used for all RSSI measurements; or

• amplitude threshold for all RSSI amplitude measurements and/or phase threshold for all RSSI phase measurements; or even

• four thresholds, namely a first amplitude threshold and a first phase threshold for RSSI amplitude and phase measurements, respectively, performed on the RFID tag side, and a second amplitude threshold and a second phase threshold for RSSI amplitude measurements, respectively. and phases on the reader side.

The final choice regarding threshold calculation for a particular configuration/setup may conveniently be made based on the estimates made in the pre-calibration step that is performed for that particular configuration/setup.

Moreover, during the pre-calibration step, it is also possible to determine the polling rate that will be used to detect the tires being transported. In fact, knowing the given average size a _x of the coverage area along the direction of transport of the tires on the conveyor belt (for example, the major axis of the elliptical coverage area 21 shown in Fig. 5) and the speed v _{x of} the moving tires (which can reasonably be considered constant), one can determine the time t _x required for the tire to get completely into the coverage area, or, equivalently, the time during which the tire is in the coverage area. Thus, the polling rate that will be used by the reader 6 to detect the tires being transported can be conveniently defined to have at least one poll during the time t _x .

In addition, for a better understanding of the read and/or write step, a preferred (albeit non-limiting) embodiment of bus detection operations performed in said read and/or write step will be described below in detail.

For convenience, during normal operation, reader 6 continuously transmits "read" commands via antenna 2, using as the transmit power value the average transmit power P _TX-av determined in the pre-calibration step, P _TX-av being such that only one RFID tag passing under the antenna could be read.

In addition, thresholds calculated from the average RSSI RSSI _T-av , RSSI _R-av in the pre-calibration step are used to detect RFID tags passing under antenna 2 and to distinguish between multiple read readings (which, as explained earlier, may be due to insufficient distance between adjacent tires on the same conveyor belt, or multiple tires on adjacent conveyor belts, or stochastic multipath phenomenon, etc.).

For convenience, the detection of an RFID tag can be generally expressed as follows:

• if RSSI _R/Tm ≥ RSSI _th , then the RFID tag (and hence the tire) is detected, or,

• if RSSI _R/Tm < RSSI _th , then the RFID tag/tire is not detected (for example, it could be before/after antenna 2 on the same conveyor belt 3 or on an adjacent conveyor belt),

where RSSI _R/Tm denotes one or more RSSI amplitude and/or phase values measured at the side(s) of the reader and/or RFID tag, and RSSI _th denotes one or more threshold values determined, as previously explained, in the preliminary step. calibration based on average values of RSSI RSSI _T-av , RSSI _R-av .

For convenience, one or more of the RSSI _th thresholds may also change dynamically and in real time to tailor the detection to a particular installation and/or environment (eg, by adding an offset value to improve detection robustness/reliability).

For convenience, proper handling of the time variation of one or more RSSI _R/Tm values also allows monitoring/monitoring of the sequence of transported tires, as shown in FIG. 6, which schematically illustrates:

• from above, a sequence of three transportable tires A, B, C, each with a corresponding RFID tag 5A/5B/5C; And,

• below, the corresponding RSSI values measured over time (assuming tires A, B, C are moving at 1 m/s and spaced 100 cm apart, and that a read power of 30 dBm is used).

Upon reading the foregoing description, those skilled in the art will immediately appreciate the technical advantages and innovative features of the present invention.

In particular, it is important to note that the present invention provides generally superior RFID read/write performance and in particular unambiguous detection of RFID tags with improved performance over currently known solutions.

Thus, the present invention can be advantageously used for automatic control, monitoring and tracking applications in the production, sorting and recycling of (smart) tires where conveyor belts are used.

Moreover, the present invention allows the implementation of tire inventory databases that store important data relating to each tire produced and are accessible (e.g. via the Internet) to relevant stakeholders (e.g., production operators, logistics operators, dealers, customers). etc.).

In conclusion, it is clear that numerous modifications and variations may be made to the present invention, all of which fall within the scope of the invention as defined in the appended claims. In this regard, it should be noted that although the invention has been described previously with specific reference to an antenna positioned above a conveyor belt, the teachings of the present invention can be immediately applied, mutatis mutandis, to various spatial configurations/positions of the antenna in relation to the conveyor. For example, the antenna may be conveniently mounted along the side edge of the conveyor belt, next to or in close proximity to said conveyor belt, and may extend perpendicular or oblique to the plane of the conveyor belt (i.e., to the aforementioned xy reference plane) and parallel to the direction of transport. . More generally, the antenna may be located next to the conveyor belt, while having such a radiation pattern that would result in a coverage area covering the entire width of the conveyor belt in the direction perpendicular to the conveyance direction, and a limited length in the direction parallel to said conveyance direction. (for convenience, it should be flat and have a given length in a direction parallel to the direction of transport, and a given width in a direction perpendicular to said direction of transport, and the given length is greater than said given width).

Claims (56)

1. Method for reading and/or writing data from/to RFID tags (5, 5A, 5B, 5C) of tires (4, A, B, C) transported on a conveyor belt (3) in the direction of transport, with each tire ( 4, A, B, C) is provided with a corresponding RFID tag (5, 5A, 5B, 5C) storing the unique identifier of said bus (4, A, B, C), this method is characterized by providing: an antenna (2) installed above or next to the conveyor belt (3) and configured to: radiation of radio frequency signals in the direction of the coverage area (21) on the conveyor belt (3), and receiving backscattered RF signals from said coverage area (21); And a reader (6) connected to the antenna (2) to control the antenna during transmission and reception; wherein the method also includes a pre-calibration step including calibrating the reader (6), wherein: a1) placing a predetermined tire (41) provided with a predetermined RFID tag (51) on a conveyor belt (3) and holding said predetermined tire (41) in a stationary state under/next to the antenna (2); a2) when the given tire (41) remains stationary under/next to the antenna (2), determine the minimum transmission power required to activate a given RFID tag (51), determining a calibration transmit power higher than said minimum transmit power, and emitting, via the antenna (2), calibration RF signals with said calibration transmission power and receiving, via said antenna (2), backscattered calibration RF signals from a predetermined RFID tag (51); a3) while continuing to emit calibration RF signals and receive backscattered calibration RF signals, gradually move the target tire (41) back and forth along the conveyor belt (3) until the target RFID tag (51) stops responding; a4) estimate the size (a _x ) of the coverage area (21) in a direction parallel to the transport direction based on operation a3); a5) measure the first received power levels of the calibration RF signals received by the predetermined RFID tag (51) when the predetermined tire (41) remains stationary under/next to the antenna (2), and when the predetermined tire (41) is moved back and forth, and second received power levels of the backscattered calibration RF signals received by the reader (6) via the antenna (2) when the target bus (41) remains stationary under/next to the antenna (2) and when said target bus (41) is moved back and forth ; a6) repeat operations a1) - a5) with different tires (41, 42, 43), thereby obtaining as a result: a plurality of calibration transmit powers related to different buses (41, 42, 43), a plurality of estimated sizes (a _x ) of the coverage area (21) related to different tires (41, 42, 43), and a plurality of first and second received power levels related to different tires (41, 42, 43); And a7) calculate average transmit power based on the received calibration transmit powers, the average size of the area (21) of the coverage based on all the estimated sizes obtained (a _x ), polling frequency based on the average area size (21) of the coverage and the given conveyor belt speed (3), average received power levels based on the received first and second received power levels, and one or more thresholds based on average received power levels; wherein the method comprises performing a reading and/or writing step, which includes operating the calibrated reader (6) in such a way that: b1) emitting, via the antenna (2), one or more RF polling signals with an average transmission power and a polling rate calculated in the pre-calibration step; b2) receiving, via the antenna (2), one or more backscattered RF interrogation signals from the RFID tag (5, 5A, 5B, 5C) of the bus (4, A, B, C) passing through the coverage area (21), wherein one or more of said backscattered interrogation RF signals carry a unique transport bus identifier (4, A, B, C); b3) measure one or more third received power levels of one or more RF polling signals received by the RFID tag (5, 5A, 5B, 5C) of the transportable bus (4, A, B, C), and one or more fourth received power levels of the backscattered RF interrogation signal received by the reader (6) via the antenna (2); b4) detecting a transportable tire (4, A, B, C) by comparing the third and fourth received power levels with one or more threshold values calculated in the pre-calibration step; And b5) identifying the detected transportable bus (4, A, B, C) based on the unique identifier carried by the backscattered interrogation RF signals. 2. The method of claim 1, wherein the step of reading and/or writing includes operating the calibrated reader (6) also to: b6) reading and/or writing tire related data from/to the RFID tag (5, 5A, 5B, 5C) of the transportable tire (4, A, B, C). 3. The method according to claim 1 or 2, wherein the antenna (2) is configured to have a radiation pattern such that results in a coverage area (21) covering: the entire width of the conveyor belt (3) in the direction perpendicular to the direction of transport; And a limited length in a direction parallel to said transport direction. 4. The method according to any one of claims 1 to 3, wherein the antenna (2) is flat, parallel to the conveyor belt (3) and has a predetermined length (L) in the direction parallel to the conveyance direction and a predetermined width (W) in the direction , perpendicular to the mentioned direction of transport, and the given length (L) is greater than the given width (W). 5. A method according to any one of the preceding claims, wherein the first, second, third, and fourth received power levels are indicative of amplitude and phase measurements of the received power. 6. System (1) for reading and/or writing data from/to RFID tags (5, 5A, 5B, 5C) of tires (4, A, B, C) transported on a conveyor belt (3) in the direction of transport, wherein each bus (4, A, B, C) is provided with a corresponding RFID tag (5, 5A, 5B, 5C) storing a unique identifier of said bus (4, A, B, C), while system (1) contains: an antenna (2) installed above or next to the conveyor belt (3) and configured to radiation of radio frequency signals in the direction of the area (21) of the coating on the conveyor belt (3) and receiving RF signals backscattered by RFID tags (5, 51, 52, 53, 5A, 5B, 5C) of tires (4, 41, 42, 43, A, B, C) passing through said coverage area (21); And a reader (6) connected to the antenna (2) for controlling the latter during transmission and reception of the antenna; wherein the reader (6) is configured to perform the pre-calibration step and, after calibration, is capable of performing the reading and/or writing step of the method according to any of the preceding claims. 7. The system of claim 6, wherein the antenna (2) is configured to have a radiation pattern that results in a coverage area (21) covering: the entire width of the conveyor belt (3) in the direction perpendicular to the direction of transport; And a limited length in a direction parallel to said transport direction. 8. The system according to claim 6 or 7, in which the antenna (2) is flat, parallel to the conveyor belt (3) and has a given length (L) in the direction parallel to the direction of transport, and a given width (W) in the direction perpendicular to said transport direction, wherein the predetermined length (L) is greater than the predetermined width (W). 9. A system according to any one of claims 6 to 8, comprising a plurality of antennas (2) which: installed in different positions along the conveyor belt (3); made, each, with the possibility of emitting radio frequency signals in the direction of the corresponding area (21) coverage on the conveyor belt (3) and receiving backscattered radio frequency signals from it; And connected to the reader (6) with the ability to operate in the transmission and reception modes; the position of each detected tire (4, A, B, C) is determined by the reader (6) or the electronic control unit (7) connected to it or integrated / built into it, based on the antenna (2) that received the backscattered radio frequency a polling signal based on which said bus is detected (4, A, B, C).

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