Radio communication device for vertically stacking objects
By designing an elliptical polarized RF antenna communication device suitable for linear polarized RF transponders, the problem of difficulty in radio frequency communication of vertical stacking of physical assets is solved, and robust and reliable communication and production costs are achieved.
Patent Information
- Application Number
- CN202380057090.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-07-28
- Filing Date
- 2023-07-25
- Publication Date
- 2025-03-14
AI Technical Summary
In logistics management, radio frequency communication of multiple physical assets stacked vertically is difficult, resulting in high production costs and unstable communication.
A radio frequency communication device is designed to communicate with an elliptical polarized radio frequency antenna using a radio frequency transponder with a linearly polarized antenna. The device includes a base, a radio frequency communication reader and a plurality of radio frequency antennas. Through a rotating system and a positioning system, the antenna is ensured to be colinear with the polarization axis of the transponder and optimize communication energy.
It realizes robust and reliable RF communication between multiple physical assets stacked vertically without changing the physical assets stacking, reducing production costs and improving communication efficiency.
Smart Images
Figure CN119631079A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of logistical management of connected or connectable assets, in particular assets of the tyre casing type, whether or not mounted on a rim. Background Art
[0002] The development of electronic objects in matter or physical assets (such as tire casings), enabling said assets to be connectable and connected, has facilitated the development of new services, for example, to optimize the use or identification of physical assets. The emergence of such digital capabilities has caused a rethinking of certain operations (in particular those managing physical assets) in order to focus actions when physical assets are rarely used or when the electronic objects contained in said physical assets are available or rarely used. For operations such as digital identification of stacked physical assets or checking the compliance of stacks of physical assets, all the physical assets to be communicated must be legible to ensure the reliability of the information exchanged with them, without hampering the formation of said physical assets. Changing the formation of a physical asset will lead to the downtime of the physical asset, which is detrimental to the productivity related to said physical asset: its transportation time is extended and the physical asset is not used during this phase. Although physical assets are capable of communication, the devices of these physical assets are usually silent to save their own energy or because they have no energy.
[0003] It is therefore necessary to activate the communication of the communication devices of these physical assets, in particular to supply them with energy so that they can respond, or to check the suitability of the information sent by the communication devices for the purpose of the stack of physical assets. All these operations are time-consuming and therefore detrimental to the productivity of these physical assets provided with the communication devices. Typically, the devices communicate via radio frequency waves and include a transponder capable of capturing the transmitted radio frequency signal, interpreting it and performing an action in response to it (which may be, for example, the transmission of another radio frequency signal).
[0004] In the logistics stage, physical assets exist in large quantities, and the devices that handle assets are usually made of metal, which is not conducive to the radio frequency communication of the communication device. In order to overcome this communication difficulty, the physical assets must be positioned so that the communication device is oriented away from the metal area. These operations are time-consuming because they require operating the physical assets on the conveyor line or outside the conveyor device, which is not conducive to the productivity of the physical assets transported by the conveyor line. Another solution is to increase the radio frequency communication power, which may lead to spontaneous inquiries of some physical assets located near the target physical assets, resulting in a higher scrap rate of physical assets, which is also not conducive to reducing the production cost of physical assets.
[0005] The subject matter of the invention described below aims to ensure radio frequency communication of multiple physical assets stacked vertically, in order to reduce the production costs associated with the use of said physical assets, while ensuring robust and reliable radio frequency communication between said physical assets and external systems. Everything is done in the stacking flow of the physical assets, without having to change the stack if it is as expected. The first goal is to read all the identifiers in the stack. The second goal is to be able to recognize the order of the identifiers in the stack, even according to the orientation of the objects corresponding to the orientation of the stack, when the radio frequency transponders of the objects are set on one side or the other of the objects, and to be able to recognize the direction in which the objects are placed in the stack. Summary of the invention
[0006] The invention relates to a radio frequency communication device adapted to communicate with a radio frequency transponder having a linearly polarized antenna, said radio frequency transponder being attached to a geometrically stable object, said device being adapted to receive at least two of said objects placed vertically adjacent to each other so as to form a stack surrounded by a cylinder, and wherein the polarization of the radio frequency transponders of the geometrically stable objects is mainly oriented in a circumferential direction relative to the axis of rotation of the cylinder surrounding the stack of at least two objects, said device comprising:
[0007] - a base adapted to receive a stack of vertically arranged objects, a normal to said base defining a vertical direction,
[0008] - at least one radio frequency communication reader adapted to generate an electrical signal to be sent to the radio frequency antenna or to read an electrical signal from the radio frequency antenna,
[0009] - a first arm, the major dimension of which extends along a first direction, said first direction preferably being co-linear with the vertical direction,
[0010] - the first arm comprises at least two radio frequency antennas spaced apart from each other by a distance d along a first direction.
[0011] The device is characterized in that it includes a system for rotating around a rotation axis colinear with the vertical direction, the system is suitable for rotating a part of a base suitable for receiving a stack of vertically arranged objects relative to at least one first arm, each of the at least two radio frequency antennas is connected to a single port of the at least one radio frequency communication reader, the at least two radio frequency antennas are elliptically polarized, preferably linearly polarized, the radio frequency antennas have an electric field E, the radial component of the electric field E is less than one quarter of the modulus of the electric field E, and the circumferential component of the electric field E is greater than 0.7 times the modulus of the electric field E in a cylindrical coordinate system related to the rotation axis of the rotation system, and the first arm is radially positioned outside relative to the rotation axis of the rotation system, suitable for being presented on the outside of a cylinder surrounding the stack of objects received by the device.
[0012] The physical asset may have communication devices disposed within its structure or on its surface. If the physical asset is axisymmetric about an axis of rotation, even if the angular position of the communication devices within the physical asset can be limited, the assets will be stacked rather than angularly positioned relative to each other to avoid wasting cycle time for this purpose. The axisymmetry of the physical asset often makes the azimuthal positioning of the physical assets relative to each other irrelevant.
[0013] In this case, the angular scan between the stacked physical assets and the first arm by the rotation system ensures that all transponders of the physical assets are read. The rotation system can rotate the stack of objects alone, or the first arm alone, or rotate both objects in different ways (e.g., in different rotation directions or different rotation speeds). As long as each geographical area of the physical assets is observed for the same period of time during the reading phase, all radio frequency transponders associated with all stacked physical assets will be read evenly.
[0014] In order to distinguish the vertical position of the radio frequency transponders, at least two radio frequency antennas spaced vertically apart from each other must be provided in order to communicate with different areas of the stack. Therefore, radio frequency transponders present only in this area of the stack will communicate with the radio frequency antenna associated with this area. In order to divide the stack of physical assets into different areas, the antennas are spaced apart from each other in the direction of the stack, for example, the method can start the transmission and reception of radio frequency waves on another antenna when one of the antennas is turned off. By having multiple radio frequency antennas and alternating the use of antennas that communicate with the radio frequency transponders of the assets, all transponders can be read and the relative vertical position of the transponders relative to each other can be established. The second function determines the order of the physical assets in the stack. For this purpose, it is sufficient to connect the radio frequency antennas to a radio frequency communication reader.
[0015] The radio frequency transponder of the physical asset has a linearly polarized antenna oriented mainly in the circumferential direction relative to the axis of rotation of the cylinder surrounding the stack, that is, the electric field E of the antenna has a radial component in the cylindrical coordinate system related to the axis of rotation of the rotating system, the amplitude of which is less than one quarter of the magnitude of the electric field E. In fact, for a physical asset such as a tire, the electric field E of the linearly polarized antenna is mainly circumferential if the transponder is located on the sidewall of the tire, and may be axial if the transponder is located on the crown of the tire. In order to ensure effective communication between the radio frequency transponder of the physical asset and the radio frequency antenna of the device, the polarization axis of the radio frequency antenna of the device must be colinear with the polarization axis of the radio frequency transponder of the physical asset. To this end, the polarization axis of the radio frequency antenna is mainly oriented in the circumferential direction relative to the axis of rotation of the stack by the component of the electric field E surrounding each radio frequency antenna relative to the axis of rotation of the rotating system. In a cylindrical coordinate system, the unique characteristics of the components of the electric field generated by the radiofrequency antenna of the device according to the invention ensure that the circumferential component of the electric field E is at least equal to 0.7 times the modulus of the electric field E generated by the radiofrequency antenna when transmitting. In addition, the radial component of the electric field E is the component with the smallest amplitude. Therefore, the polarization axis of the radiofrequency antenna of the device is substantially collinear with the polarization axis of the transponder of the physical asset, which ensures high-quality radiofrequency communication. Therefore, due to the collinearity between the axis of the linear antenna and the electric field E, the communication energy of the device is optimized to communicate with the transponder of the physical asset, which ensures improved communication between the antennas, which makes it possible to apply higher relative rotation speeds between the stack of physical assets and the arm provided with the antenna, while maintaining high-quality communication. To this end, the radiofrequency antenna of the device is elliptically polarized, preferably linearly polarized, as long as the circumferential component is dominant. The polarization of the antenna is the adaptation of the antenna to the electric field to optimize the energy exchanged between the antenna and the electric field, and must not be confused with the directivity of the antenna, which enables the energy to be concentrated in the spatial area around the antenna.
[0016] Advantageously, the communication device comprises a system for positioning the arm relative to the axis of rotation of the rotation system, the system defining the orbit of the first arm.
[0017] Thus, the communication device can adapt, regardless of the diameter of the cylinder surrounding the stack of physical assets, while ensuring an acceptable distance between the radio frequency transponders of the physical assets rotating about the axis of rotation of the rotation system and the radio frequency antenna of the communication device. However, the communication device can also adapt, regardless of the angle of the cone of the stack of physical assets, by tilting the first direction of the arm with the vertical direction of the base, while ensuring a similar distance between the radio frequency transponders of the physical assets forming the cone and the radio frequency antenna of the communication device. The trajectory followed by the arm in positioning relative to the stack can be, for example, a translation, a rotation about an axis, or a combination of a translation and a rotation about an axis.
[0018] Preferably, the system for positioning the first arm comprises a system for guiding the first arm in translation along a translation direction, said translation direction preferably intersecting the axis of rotation of the rotation system.
[0019] The most basic movement of the arm is a translation in a single direction. Preferably, this direction intersects the axis of rotation of the rotating system, which permanently ensures that the polarization axis of the radio frequency antenna of the device remains mostly circumferential relative to the axis of rotation of the rotating system.
[0020] According to another embodiment, the device comprises an actuation system adapted to move the first arm relative to the trajectory defined by the positioning system.
[0021] This allows the arm to be automatically positioned relative to the stack of physical assets without human intervention.
[0022] Advantageously, the communication means comprise a stopper, preferably comprising a sensor, suitable for stopping the movement of the first arm along the trajectory defined by the positioning system when a threshold value is reached.
[0023] In order to automate the device and in order not to damage the stacked physical assets, the device comprises a stop suitable for stopping the movement of the arm on the track defined by the positioning system. The stop can be provided with a sensor or comprise an open loop, evaluating the proximity of the arm to the stacked physical assets by a specific value. The sensor can be a force sensor measuring the contact force between the arm and the physical asset, or a proximity sensor evaluating the distance between the arm and the outer surface of the vertical stack. However, in the case of an open loop, pneumatic or hydraulic or electrical or magnetic set points can be used.
[0024] According to a particular embodiment, the communication device comprises a system for centering relative to the axis of rotation of the rotating system.
[0025] Preferably, the centering system comprises at least one vertical second arm connected to the first arm radially with respect to the axis of rotation of the rotation system.
[0026] The stack of physical assets and / or the first arm are preferably positioned relative to the axis of rotation of the rotating system. Thus, the arm is positioned relative to the stack at an angular position relative to the axis of rotation that enables a higher speed angular scanning of the stack of physical assets or the first arm. The centering system may include a series of vertical arms, in particular including a first arm, whose concentric movement is uniform relative to the axis of rotation. Thus, the concentric movement of the arm tends to position the stack of physical assets so that the axis of rotation of the cylinder surrounding the stack coincides with the axis of rotation of the rotating system. To achieve this, the second arm only needs to extend vertically at least on the physical assets located at one end of the stack. Typically, the physical assets located in the vicinity of the base have the largest radial dimensions to ensure the stability of the vertical stack, in which case the second arm is located in the vicinity of the base. The arm system is capable of moving the stack of physical assets on the base.
[0027] Preferably, the rotation system is integrated into a base of the communication device.
[0028] This is a compact embodiment in which the rotation system extends from the base to rotate the stack of physical assets and / or the first arm (e.g., by lifting them from the base). Once the rotation is completed, the rotation system disappears under the base to be able to handle the stack of physical assets. An alternative embodiment is to position the rotation system vertically above the stack, which requires specific components that are connected to the stack but do not form part of the stack.
[0029] According to a particular embodiment, the communication device comprises movement means integrated into the base, the movement means defining a track passing through the axis of rotation of the rotation system, the movement means being suitable for moving along the track a stack of physical assets received by the device.
[0030] These moving means enable the stack of physical assets to be handled on a base. For example, the moving means may be a roller belt. Furthermore, the moving means can also center the stack of physical assets relative to the axis of rotation of the rotating system by facilitating the movement of the stack along a defined track, since the track intersects the axis of rotation.
[0031] Preferably, each of the radio frequency antennas is connected to a single port of said at least one radio frequency communication reader.
[0032] Therefore, the communication between the radio frequency antenna of the communication device and the radio frequency transponder of the physical asset is not necessarily sequential, which enables saving the communication time between the communication device and the stack of objects.
[0033] Preferably, each RF antenna defines a communication area according to the electric power provided, the communication area is characterized by a gain defining a maximum distance Di from the communication area and a beam angle αi, and a distance d between two adjacent RF antennas along the first direction is less than a threshold value A defined by the following formula: [Mathematical Formula 1] A=∑ i D i *cos(α i ).
[0034] This ensures that no white spots of electromagnetic radiation will appear between two antennas that are adjacent on the stack. One of the possible means for ensuring the geographical coverage of the antennas is to adjust the electrical power supplied to the radio frequency antennas within the limits of the current standards. Providing the first arm with sufficient radio frequency antennas to cover a height higher than the highest height of the stack of physical assets ensures that the communication device covers the interrogation and reading of any stack of physical assets. This ensures that all radio frequency transponders of the physical assets of the stack will be interrogated and listened to by the communication device.
[0035] Preferably, the at least two radio frequency antennas are selected from the group consisting of a dipole antenna, a slot antenna, a loop antenna and a patch antenna.
[0036] The first two antennas (dipole antenna and slot antenna) are linearly polarized antennas, and the axis of the dipole antenna or the axis of the slot antenna defines the polarization axis of the antenna. The last two antennas (loop antenna and patch antenna) are circularly polarized or elliptically polarized antennas. The plane of the antenna will be positioned in a plane, the normal of which is essentially the radial direction of a cylindrical coordinate system associated with the axis of rotation of the rotating system. Optionally, the shape of the antenna can be determined so as to be biased towards one of the two directions defining the plane of the antenna, thereby obtaining an elliptically polarized antenna that can be biased towards the circumferential direction of a cylindrical coordinate system associated with the axis of rotation of the rotating system, rather than the radial direction.
[0037] The invention also relates to the use of a communication device with a stack of objects selected from the group consisting of a tire casing, a wheel, a wheel valve such as a valve of the TPMS (Tire Pressure Monitoring System) type, and an elastic element of a mounting assembly.
[0038] For example, these are physical assets that can be stacked to define a mounting assembly for a particular vehicle. The tire casing may include an RFID (radio frequency identification) tag located in the sidewall of the tire and oriented circumferentially relative to the natural rotation axis of the tire casing. The wheel and valve of the mounting assembly may also be provided with a radio frequency transponder whose communication antenna is oriented circumferentially relative to the natural rotation axis of the wheel, which natural rotation axis coincides with the rotation axis of the tire casing of the mounting assembly.
[0039] The invention also relates to a conveyor line suitable for conveying stacked objects along a given path, said conveyor line comprising communication means suitable for communicating with radio frequency transponders connected to these objects.
[0040] Preferably, the radio frequency communication device is located between two conveying devices, the first conveying device located upstream of a given path comprising a centering system suitable for positioning the stack of objects relative to the width of the radio frequency communication device.
[0041] In the field of logistics, the integration of radio frequency communication devices along a conveyor line makes it possible to monitor the stacking of objects while conveying the stacking, while minimizing the fixing of the stacking of objects, which ensures competitive production costs. If the stacking is non-compliant, it is also possible to remove the stack of non-compliant objects from the stacking flow by integrating the radio frequency communication device between two conveying devices of the conveyor line; thus, the identification function and the ordering of the products and optionally their placement direction are optimized. The stacking is centered in a direction transverse to the track defined by the radio frequency communication device, ensuring that the stack is pre-set relative to the communication device. Therefore, if the communication device is provided with an integrated moving device and a centering device, the centering of the stack relative to the track can minimize the centering of the stack in a direction perpendicular to the track of the moving device of the communication device. Therefore, the centering device of the communication device consists of aligning the axis of rotation of the cylinder surrounding the stack of physical assets with the axis of rotation of the rotation system included in the communication device. Therefore, the size of the centering system is minimized, thereby reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0042] The invention will be better understood on reading the following description, which is given by way of non-encircling example only, and with reference to the accompanying drawings, in which like reference numerals refer to like parts in all cases, and in which:
[0043] Figure 1 is a perspective view of a first radio frequency communication device according to the present invention,
[0044] Figure 2 is a perspective view of a second radio frequency communication device according to the present invention,
[0045] Figure 3 is the radiation pattern of the RF antenna,
[0046] Figure 4 shows a stack of physical assets including tire casings provided with RFID (radio frequency identification) tags,
[0047] Figure 5 is a perspective view of a conveyor line including a radio frequency communication device. DETAILED DESCRIPTION
[0048] Figure 1A first radio frequency communication device 1 is shown. The device comprises a base 2, the base 2 defining a vertical direction 21 along a normal to an outer surface of the base, the other elements of the radio frequency device 1 being positioned relative to the base 2, and the base 2 corresponding to a surface in contact with a stack of physical assets. The device 1 further comprises a first arm 4, the main direction of which defines a first direction 22. The first direction 22 is colinear with the vertical direction 21.
[0049] The device 1 comprises a rotation system 5 of the stack of physical assets, here integrated into the base 2 of the device 1 and represented by a cross that rotates around a rotation axis 31. This cross 5 also translates in a vertical direction 21, so that it is located below or above a fixed outer surface of the base 2, depending on the communication phase between the device 1 and the stack of physical assets. Thus, the stack of physical assets can be fixed or translated relative to the fixed part of the base 2 of the device 1.
[0050] The first arm 4 is provided with radio frequency antennas 10a, 10b, 10c spaced apart by a distance d. These radio frequency antennas 10a, 10b, 10c are electrically connected to the radio frequency reader 3, which transmits or receives radio frequency signals to or from the radio frequency antennas. The radio frequency antennas 10a, 10b and 10c are physically connected to the radio frequency reader 3 through ports on the radio frequency reader 3. The antennas of the device are elliptically polarized, preferably linearly polarized, so that the main component of the transmitted electric field is borne by the circumferential direction in a cylindrical coordinate system related to the rotation axis 31 of the rotating system 5.
[0051] Here, the stack of physical assets is translated relative to the device 1 by means 12 for moving the stack. These moving means 12, which are integrated into the base 2, comprise here a series of rollers parallel to one another. Each roller rotates around an axis, and here, the axes are colinear. Thus, a track 121 for the stack of physical assets is formed with the rollers. Here, this track 121 passes through the axis of rotation 31 of the rotating system 5. These moving means 12 can easily guide the stack of physical assets on the base 2 so that the stack of physical assets is positioned relative to the axis of rotation 31 of the rotating system 5 of the device 1. In this case, the rotating system 5 rises above the outer surface of the base 2 so that it carries the stack of physical assets, thereby separating the stack of physical assets from the outer surface of the base 2. Then, the rotating system 5 begins to rotate around its axis of rotation 31 to rotate the stack of physical assets.
[0052] In this configuration, the first arm 4 is guided in translation by a positioning system 6. Here, the positioning system 6 comprises a translation guide system 7 comprising a groove in the outer surface of the base 2. The groove 7 defines a translation direction 71 passing through the axis of rotation 31 of the rotation system 5. This enables the first arm 4 to be brought closer relative to the stack of physical assets, regardless of the radial size of the stack of physical assets.
[0053] The first arm 4 is driven by an actuation system comprising an electric, pneumatic or hydraulic power source and ensuring automatic translation of the first arm 4 along the direction 71. Likewise, in order to automate the positioning of the first arm 4, the device 1 here comprises a stopper which controls the movement of the first arm along the track 7 as a function of the proximity of the first arm 4 relative to the stack of real assets. Thus, the stopper comprises a sensor which determines the distance between the sensor and the stack of real assets in order to stop the movement of the first arm 4 as a function of the relationship between the measurement value provided by the sensor and a threshold value representing a collision of the first arm 4 with the stack of real assets. The sensor is an electromagnetic or optical proximity sensor or a contact sensor.
[0054] The translation guidance system 7 enables the radio frequency antennas 10a, 10b and 10c of the first arm 4 to be uniquely positioned such that the polarization direction of these antennas 10a, 10b and 10c is mainly circumferential with respect to the rotation axis 31 of the rotation system 5. Here, the radio frequency antennas 10a, 10b and 10c are elliptically polarized loop antennas, the main direction of which extends circumferentially with respect to the rotation axis 31.
[0055] Finally, the device 1 here comprises a centering system 9 which enables the stack of physical assets to be properly positioned relative to the rotation system 5, more precisely, the axis of rotation of the cylinder surrounding the stack of physical assets to be coaxial with the axis of rotation 31 of the rotation system 5. This makes it possible to improve the dynamic stability of the stack of physical assets (especially when the stack of physical assets is in high-speed rotation) by balancing the centrifugal forces applied to the stack of physical assets over the entire periphery of the stack of physical assets. Here, the centering system 9 comprises a first arm 4 and a second arm 11. The two arms are connected to each other to ensure relative translation so that the distance between each arm and the axis of rotation 31 of the rotation system is the same. To this end, the second arm 11 translates in the same direction 71 as the first arm 4 through a groove formed in the outer surface of the base 2.
[0056] Furthermore, this centering of the stack of physical assets ensures that the distance between the first arm 4 and any material point of the stack of physical assets located at the height H of the stack along the vertical direction 21 is the same. Therefore, the radio frequency communication between the radio frequency transponder of the physical asset and the radio frequency antennas 10a, 10b and 10c of the first arm 4 is uniform.
[0057] Figure 2A second radio frequency communication device 1 according to the present invention is shown. The device 1 still comprises a base 2 adapted to support a stack of physical assets. The device 1 further comprises a first arm 4 provided with radio frequency antennas 10a, 10b, 10c, which are connected to the radio frequency reader 3 via connection ports on the radio frequency reader 3. However, here, the first arm 4 extends mainly along a first direction 22, which is not necessarily co-linear with a vertical direction 21 defined by an outer surface of the base 2, which is used to receive the stack of physical assets.
[0058] The device 1 comprises a system 5 for rotating about an axis of rotation 31. However, the rotating system 5 drives the rotation of the first arm 4, rather than Figure 1 Rotation of the stack of physical assets shown.
[0059] The device 1 also comprises a system 6 for positioning the first arm 4 relative to the axis of rotation 31 of the rotation system 5. The positioning system 6 comprises firstly a system 7 for guiding the translation by means of a groove. The groove defines a trajectory of the first arm 4 along a translation direction 71. Here, the translation direction 71 intersects the axis of rotation 31 of the rotation system 5. The positioning system 6 also comprises a system for rotating the first arm 4 relative to the axis of rotation 41, so as to define the first direction 22 of the first arm 4.
[0060] The movement of the first arm 4 by the positioning system 6 is performed automatically by an actuation system. This actuation system controls the rotation of the first arm 4 around the rotation axis 41 and the translation of the first arm 4 along the translation direction 71 to ensure the proximity of the first arm 4 relative to the stack of physical assets. In addition, the device 1 comprises a stopper controlling the drive of the first arm 4. Therefore, this stopper comprises a sensor that determines the distance between the sensor and the stack of physical assets in order to stop the movement of the first arm 4 according to the relationship between the measurement value provided by the sensor and the threshold value representing the collision of the first arm 4 and the stack of physical assets. The sensor is an electromagnetic or optical proximity sensor or a contact sensor.
[0061] Here, the stack of physical assets is translated relative to the device 1 by means of stacking moving devices 12. These moving devices 12, which are integrated into the base 2, here comprise a series of rollers parallel to one another, which can also be slide beds. Each roller rotates around an axis, and here, the axes are colinear. Thus, a track 121 for the stack of physical assets is formed by means of the rollers.
[0062] Here, the rail 121 passes through the rotation axis 31 of the rotation system 5. These moving devices 12 can easily guide the stack of physical assets on the base 2 so that the stack of physical assets is positioned relative to the rotation axis 31 of the rotation system 5 of the device 1.
[0063] Finally, the device 1 here comprises a centering system 9 which enables the stack of physical assets to be properly positioned relative to the rotation system 5, more precisely, the axis of rotation of the cylinder surrounding the stack of physical assets to be coaxial with the axis of rotation 31 of the rotation system 5. Here, the centering system 9 comprises four second arms evenly arranged on both sides of the device 12 for moving the stack of physical assets. The four second arms are connected to each other to ensure a clamping movement around the axis of rotation 31 of the rotation system 5, so that the distance between each arm and the axis of rotation 31 of the rotation system 5 is the same. To this end, the second arms here translate along two translation directions by means of grooves formed in the outer surface of the base 2. The two translation directions intersect each other at the axis of rotation 31 of the rotation system 5.
[0064] Furthermore, this centering of the stack of physical assets ensures that the distance between the first arm 4 and any material point of the stack of physical assets located at the height H of the stack along the vertical direction 21 is the same. Therefore, the radio frequency communication between the radio frequency transponder of the physical asset and the radio frequency antennas 10a, 10b and 10c of the first arm 4 is uniform.
[0065] Figure 3 The main RF radiation lobe 51 of the RF antenna 10a of the first arm of the RF communication device is shown in a plane defined by the polarization axis 50 of the RF antenna 10a and the first direction 22 of the first arm. Here, the RF antenna 10a is a half-wave dipole antenna.
[0066] According to the power supplied to the antenna, it radiates omnidirectionally so that the equal power curves show closed contours at both ends of the antenna 10a. Figure 3 The RF radiation isopower curve 51 is shown. Then, the distance D and the beam angle α associated with the RF antenna can be determined, which can characterize the effective communication area of the antenna 10a. Here, since the communication area of the dipole antenna is axisymmetric relative to the polarization axis 50 of the antenna, the description is limited to the subspace.
[0067] Therefore, an effective distance D' is determined, which corresponds to the product of cos α and the distance D of the equal power curve 51, which determines the distance at which at least half of the RF power is exchanged between the RF antenna 10a and the material point in space located at the distance D'.
[0068] Since the RF antennas are positioned along the first direction of the first arm, the spacing d between two adjacent antennas along the first direction must be smaller than the sum of the distances D' associated with the RF antennas.
[0069] Figure 4A stack 200 of physical assets is shown. Here, the physical assets are four mounted assemblies of which only tire casings 210a, 210b, 210c and 210d are shown. The casings are stacked on top of each other along a direction defined by axis 202. Thus, the stack 200 may be surrounded by a right cylinder having axis 202, the diameter of which corresponds to the outermost diameter of the tire casings 210a, 210b, 210c and 210d.
[0070] Here, the stack 200 is placed on a base 201 to facilitate the movement of the stack 200. The base 201 is provided with a moving device (such as casters) on the surface opposite to the surface in contact with the stack 200. Figure 4 Thus, the stack 200 can be manually positioned relative to the RF communication device, in particular, the stack 200 can be positioned relative to the first arm of the RF communication device and the axis of rotation of the rotation system. In this case, the RF communication device does not necessarily require a device for moving the stack of physical assets.
[0071] Each tire casing 210a, 210b, 210c and 210d is provided with a radio frequency transponder 211a, 211b, 211c and 211d, which in this case is an RFID tag comprising an electronic chip coupled to a half-wave dipole radio frequency antenna, which is a linearly polarized antenna. The radio frequency antenna extends circumferentially relative to the axis 202 along its major dimension.
[0072] Figure 5 A conveyor line 100 for stacking physical assets is shown, the conveyor line 100 comprising a radio frequency communication device 1. Here, the device 1 corresponds to Figure 1 The device shown in .
[0073] The conveyor line 100 defines a path 110 along which a stack of physical assets travels from a starting point to an end point. Here, the path 110 extends over three combined parts of the conveyor line 100, namely a first conveyor device 101a located upstream of the path 110, a second conveyor device 101b located downstream of the path 110, and a radio frequency communication device 1 located between the two conveyors 101a and 101b. Here, the two conveyors 101a and 101b are provided with drive rollers, the main direction of which is perpendicular to the path 110. The first conveyor device 101a includes a centering system 102 to guide the stack of physical assets to the middle of the width of the conveyor device 101a, thereby preparing for the stack of physical assets to pass in front of the radio frequency communication device 1. Since the radio frequency communication device 1 is located in the middle of the width of the first conveyor device 101a, the centering system is provided with two channel constriction elements 102 symmetrically relative to the path 110.
Claims
1. A radio frequency communication device (1) adapted to communicate with a radio frequency transponder having a linearly polarized antenna, the radio frequency transponder being attached to a geometrically stable object, the device (1) being adapted to receive at least two of the objects placed vertically adjacent to each other to form a stack surrounded by a cylinder, and the polarization of the radio frequency transponders of the geometrically stable objects being oriented mainly in a circumferential direction relative to an axis of rotation of the cylinder surrounding the stack of at least two objects, the device (1) comprising: - a base (2) suitable for receiving a stack of vertically arranged objects, the normal of said base defining a vertical direction (21), - at least one radio frequency communication reader (3) adapted to generate an electrical signal to be sent to the radio frequency antenna or to read an electrical signal from the radio frequency antenna, - a first arm (4) having a major dimension extending along a first direction (22), said first direction (22) being preferably colinear with the vertical direction (21), - the first arm (4) comprises at least two radio frequency antennas (10a, 10b, 10c) spaced apart from each other by a distance d along a first direction (22), Characterized in that the radio frequency communication device (1) comprises a system (5) for rotating around a rotation axis (31) colinear with the vertical direction (21), the system (5) being adapted to rotate a portion of a base (4) adapted to receive a stack of vertically arranged objects relative to a first arm (4), each of the at least two radio frequency antennas (10a, 10b, 10c) being connected to a port of the at least one radio frequency communication reader (3), the at least two radio frequency antennas (10a, 10b, 10c) being elliptically polarized, preferably linearly polarized, the radio frequency antennas having an electric field E, the radial component of the electric field E being less than one quarter of the modulus of the electric field E, and the circumferential component of the electric field E being greater than 0.7 times the modulus of the electric field E in a cylindrical coordinate system relative to the rotation axis (31) of the rotation system (5), and the first arm (4) being radially positioned outside relative to the rotation axis (31) of the rotation system (5), being adapted to be presented on the outside of a cylinder surrounding the stack of objects received by the device.
2. The radio frequency communication device (1) according to claim 1, wherein: The radio frequency communication device (1) comprises a system (6) for positioning the first arm (4) relative to the axis of rotation (31) of the rotation system (5), the system (6) defining the trajectory of the first arm (4).
3. The radio frequency communication device (1) according to claim 2, wherein: The system (6) for positioning the first arm (4) comprises a system (7) for guiding the first arm (4) in translation along a translation direction (71) which preferably intersects the axis of rotation (31) of the rotation system (5).
4. The radio frequency communication device according to any one of claims 2 and 3, wherein: The radio frequency communication device (1) comprises an actuation system adapted to move a first arm (4) relative to a trajectory defined by a positioning system (6).
5. The radio frequency communication device (1) according to any one of claims 2 to 4, wherein: The radio frequency communication device (1) comprises a stopper, preferably comprising a sensor, adapted to stop the movement of the first arm (4) along a trajectory defined by the positioning system (6) when a threshold value is reached.
6. A radio frequency communication device (1) according to any one of the preceding claims, wherein: The radio frequency communication device (1) comprises a system (9) for centering relative to an axis of rotation (31) of a rotating system (5).
7. The radio frequency communication device (1) according to claim 6, wherein: The centering system (9) comprises at least one vertical second arm (11) connected to the first arm (4) radially relative to the axis of rotation (31) of the rotation system (5).
8. The radio frequency communication device (1) according to any one of claims 1 to 7, wherein: The rotating system (5) is integrated into the base (2) of the device (1).
9. The radio frequency communication device (1) according to any one of claims 1 to 8, wherein: The radio frequency communication device (1) comprises a moving device (12) integrated into a base (2), the moving device (12) defining a track (121) passing through the axis of rotation (31) of the rotating system (5), the moving device (12) being suitable for moving a stack of physical assets received by the device along the track (121).
10. The radio frequency communication device (1) according to any one of claims 1 to 9, wherein: Each of the radio frequency antennas (10a, 10b, 10c) is connected to a single port of the at least one radio frequency communication reader (3).
11. The radio frequency communication device (1) according to any one of claims 1 to 10, wherein: Each radio frequency antenna (10a, 10b, 10c) defines a communication area according to the electric power provided, the communication area is characterized by a gain defining a maximum distance Di from the communication area and a beam angle αi, and a distance d between two adjacent radio frequency antennas (10a, 10b, 10c) along a first direction (22) is less than a threshold value A defined by the following formula: [Mathematical formula 1] A = ∑ i D i *cos(α i ).
12. The radio frequency communication device (1) according to any one of claims 1 to 11, wherein: The at least two radio frequency antennas (10a, 10b, 10c) are selected from the group consisting of a dipole antenna, a slot antenna, a loop antenna and a patch antenna.
13. Use of a radio frequency communication device (1) according to any one of claims 1 to 12 with an object selected from the group consisting of a tire casing, a wheel, a wheel valve such as a TPMS (Tire Pressure Monitoring System) type valve, and an elastic element of a mounting assembly.
14. A conveyor line (100) adapted to convey objects placed in a stack along a given path (110), the conveyor line (100) comprising a radio frequency communication device (1) according to any one of claims 1 to 12.
15. The conveyor line (100) according to claim 14, wherein: The radio frequency communication device (1) is located between two conveying devices (101a, 101b), the first conveying device (101a) located upstream of a given path (110) comprising a centering system (102) suitable for positioning the stack of objects relative to the width of the radio frequency communication device (1).