Radio frequency identification (RFID)-based wireless passive temperature measurement system for bearing

Abstract

The invention relates to an RFID-based wireless passive temperature measurement system for a bearing, and the system comprises a temperature sensor which comprises a sensor antenna which is a linearly polarized antenna; the reader antenna is in communication connection with the temperature sensor, and the reader antenna is used for radiating a radio frequency signal; wherein the temperature sensor is fixed on the bearing, and the reader antenna is a dual-frequency dual-circularly polarized antenna. The wireless passive temperature measurement system based on the RFID can accurately monitor and obtain temperature data of the bearing in the operation process in real time, can meet frequency band requirements of different areas, and is small in size, simple in structure, flexible in design and capable of reducing research and development cost.

Description

Technical Field

[0001] The invention relates to the technical field of wireless monitoring, and in particular to an RFID-based wireless passive temperature measurement system for bearings. Background Art

[0002] Generally, the bearing fault is diagnosed by obtaining the bearing temperature data. However, it is often difficult to measure the temperature of a bearing in working state. In the related art, the bearing temperature measurement system includes: wired temperature measurement system, wireless temperature measurement system with active sensor and wireless temperature measurement system with passive sensor.

[0003] For wired temperature measurement systems, the installation and wiring of the system are complicated and not suitable for temperature measurement of high-speed rotating bearings at high speeds. For active sensors, the battery needs to be replaced after it is exhausted before it can be used, or a self-powered module needs to be designed. Due to the need for a battery module, the sensor is larger in size, which has a certain impact on the operation of high-speed bearings and is costly. For passive sensors, due to the lack of batteries, the sensitivity is higher, and the performance of wireless temperature measurement systems with passive sensors is more easily affected by the complexity of the environment (oil, metal, high-speed rotation, etc.) and the direction of the sensor antenna placement, making the energy received by the passive sensor insufficient to complete the temperature measurement.

[0004] In addition, a wireless passive temperature measurement system based on RFID is used, but its available frequency bands in different regions are different. The wireless passive temperature measurement system needs to be designed for different regions and carrying application scenarios, which will increase the R&D cost. Summary of the invention

[0005] In order to overcome the problems existing in the related art, the present disclosure provides an RFID-based wireless passive temperature measurement system for a bearing.

[0006] According to a first aspect of an embodiment of the present disclosure, the present disclosure provides an RFID-based wireless passive temperature measurement system for a bearing, comprising: a temperature sensor, comprising a sensor antenna, wherein the sensor antenna is a linearly polarized antenna; and a reader antenna, communicatively connected to the temperature sensor, wherein the reader antenna is used to radiate a radio frequency signal; wherein the temperature sensor is fixed to the bearing, and the reader antenna is a dual-frequency dual circularly polarized antenna.

[0007] In some embodiments, the reader antenna includes: a radiating unit, including a double-ring structure consisting of an inner ring and an outer ring, the inner ring and the outer ring are used to radiate electromagnetic waves of different frequency bands; a feeding network, arranged below the radiating unit and electrically feeding the radiating unit by coupling feeding; the inner ring is used to radiate 915MHz electromagnetic waves, and the outer ring is used to radiate 860MHz electromagnetic waves.

[0008] In some embodiments, the double ring structure is a double circular ring structure or a double square ring structure.

[0009] In some embodiments, the feeding network includes: a branch line coupler, including a first output branch and a second output branch; a coupled feed port, including a first coupled feed port and a second coupled feed port, the first coupled feed port is connected to the first output branch, the second coupled feed port is connected to the second output branch, the first coupled feed port and the second coupled feed port form a 90° phase gradient, wherein the coupled feed port is an I-shape, the two horizontal lines of the I-shape correspond to the inner ring and the outer ring of the radiating unit respectively, and the length of the vertical line of the I-shape is the spacing between the inner ring and the outer ring.

[0010] In some embodiments, the second output branch includes: a first line parallel to the first output branch; and a second line perpendicular to the first line, wherein the vertical lines of the first coupled feed port and the second coupled feed port are perpendicular to the first output branch and the second line of the second output branch, respectively.

[0011] In some embodiments, the branch line coupler further includes: a first input branch line, parallel to the first output branch line; a second input branch line, parallel to the first output branch line; and a square structure, wherein the first output branch line, the second output branch line, the first input branch line and the second input branch line are respectively led out from the four vertices of the square structure.

[0012] In some embodiments, the sensor antenna is a patch antenna comprising a high dielectric constant material.

[0013] In some embodiments, the RFID-based wireless passive temperature measurement system for bearings further includes: a reader; a coaxial cable for electrically connecting the reader and the reader antenna; a processing terminal; and a Zigbee module electrically connected to the processing terminal, wherein the Zigbee module is used to wirelessly transmit the data information collected by the reader to the processing terminal.

[0014] The technical solution provided by the embodiments of the present disclosure may include the following beneficial effects: the RFID-based wireless passive temperature measurement system for bearings disclosed in the present disclosure can monitor and obtain the temperature data of the bearings during operation in real time and accurately, and can meet the frequency band requirements of different regions. In addition, the circularly polarized antenna does not need to be aligned with the polarization of the sensor antenna. The circularly polarized antenna can reduce the system's sensitivity to the orientation of the sensor antenna and can effectively avoid the loss caused by polarization mismatch. It has a small size, a simple structure, a flexible design, and reduces R&D costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0016] Figure 1 is a schematic diagram of an RFID-based wireless passive temperature measurement system for a bearing according to an exemplary embodiment;

[0017] Figure 2 is a top view of a radiation unit according to an exemplary embodiment;

[0018] Figure 3 is a top view of a radiation unit according to another exemplary embodiment;

[0019] Figure 4 is a top view of a feeding network according to an exemplary embodiment. DETAILED DESCRIPTION

[0020] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0021] In order to solve the above technical problems, the present disclosure provides an RFID-based wireless passive temperature measurement system 100 for a bearing, which is used to monitor and obtain temperature data of a bearing 70 in real time and accurately during operation.

[0022] like Figure 1 As shown, the RFID-based wireless passive temperature measurement system 100 includes a temperature sensor 10 , a reader antenna 20 , a coaxial cable 40 , a reader 30 , a Zigbee module 60 and a processing terminal 50 .

[0023] The reader 30 is electrically connected to the reader antenna 20 via a coaxial cable 40. The Zigbee module 60 is electrically connected to the processing terminal 50. The Zigbee module 60 is used to wirelessly receive the data information collected by the reader 30 and transmit it to the processing terminal 50.

[0024] Radio Frequency Identification (RFID) technology uses non-contact data communication between the reader 30 and the tag to achieve the purpose of identifying the target. The basic working principle of RFID is as follows: after the tag enters the magnetic field, it receives the radio frequency signal sent by the reader 30, and the generated induced current provides energy for sending the product information stored in the chip.

[0025] Furthermore, the temperature sensor 10 can be equivalent to the tag in the above-mentioned RFID. The temperature sensor 10 is fixed to the inner wall of the inner ring or the outer wall of the outer ring of the bearing 70, or the end face of the inner ring or the outer ring, and rotates with the bearing 70. The temperature sensor 10 includes a temperature measuring chip (not shown in the figure) and a sensor antenna 11, and the temperature measuring chip is integrated on the sensor antenna 11.

[0026] Furthermore, the antenna type of the sensor antenna 11 is a microstrip patch antenna, which can resist metal interference, and realize dual-band by cutting a groove on the radiation surface of the sensor antenna 11, which is convenient for realizing dual-frequency. In addition, the impedance matching (also called conjugate matching) with the temperature measurement chip is achieved by adjusting the width of the groove. The sensor antenna 11 adopts a high dielectric constant material, so that the sensor antenna 11 can be miniaturized.

[0027] Among them, the temperature sensor 10 is a wireless passive sensor. Compared with an active sensor, no additional battery or cable is required to power the temperature sensor 10, and the use of cables is reduced, and complex wiring is avoided, so it is more suitable for the working environment of the bearing 70. In addition, the wireless passive sensor does not need to install batteries, which reduces the weight and volume of the battery, has little impact on the operation of the bearing 70, is easy to install, and there is no need to worry about running out of power, avoiding frequent battery replacement.

[0028] Furthermore, the reader antenna 20 is wirelessly connected to the sensor antenna 11, and the reader antenna 20 is used to radiate or transmit radio frequency signals. The reader 30 transmits a radio frequency signal (also known as electromagnetic wave, radio wave) energy of a specific frequency to the temperature sensor 10 to drive the temperature sensor 10 to send out its internal signal or data.

[0029] Specifically, the sensor antenna 11 generates an induced current by receiving the radio frequency signal emitted by the reader antenna 20 , thereby providing sufficient energy for the temperature measuring chip in a short period of time during the rotation temperature measurement, so that the temperature measuring chip transmits the temperature signal to the reader antenna 20 .

[0030] The reader antenna 20 is a dual-frequency dual-circular polarization antenna, and the sensor antenna 11 is a linear polarization antenna.

[0031] The size of the RF signal induced by the linear polarization antenna is related to the polarization direction of the transmitting and receiving antennas. That is, when the polarization directions of the transmitting and receiving antennas are consistent, the polarization loss is minimal. The linear polarization antenna can be installed vertically, horizontally or on any other plane, and can receive RF signals.

[0032] The radio frequency signal transmitted or received by the circularly polarized antenna is independent of the polarization direction of the sensor antenna 11. The circularly polarized antenna does not need to be polarized and aligned with the sensor antenna 11. The circularly polarized antenna can reduce the system's sensitivity to the orientation of the sensor antenna 11 and can effectively avoid losses caused by polarization mismatch.

[0033] Furthermore, the reader antenna 20 includes a radiation element 21 and a feeding network 22 .

[0034] like Figure 2 and Figure 3 As shown, the radiation unit 21 includes a double-ring structure consisting of an inner ring 211 and an outer ring 212, and the inner ring 211 and the outer ring 212 are used to radiate electromagnetic waves of different frequency bands; the feeding network 22 is arranged below the radiation unit 21 and is fed with the radiation unit 21 by coupling feeding; wherein, the inner ring 211 is used to radiate 915 MHz electromagnetic waves, and the outer ring 212 is used to radiate 860 MHz electromagnetic waves (also called radio waves, radio frequency signals).

[0035] Among them, the electromagnetic wave of 915MHz can measure the temperature of the bearing 70 in the Chinese region, and the electromagnetic wave of 860MHz can measure the temperature of the bearing 70 in the European region. It can be seen that the reader antenna 20 disclosed in the present invention can be applied to different regions without special design for a specific region, thereby reducing the design cost.

[0036] In the embodiment, the double ring structure is a double circular ring structure (such as Figure 2 as shown) or a double ring structure (as Figure 3 The design of the dual-loop structure facilitates the reader 30 to achieve the dual-frequency radiation characteristic.

[0037] Furthermore, if Figure 4 As shown, the feed network 22 includes branch line couplers and coupled feed ports.

[0038] The branch line coupler includes a square structure 227 and a first output branch line 221, a second output branch line 222, a first input branch line 225 and a second input branch line 226. The coupling feed port includes a first coupling feed port 223 and a second coupling feed port 224, which are respectively connected to the first output branch line 221 and the second output branch line 222, wherein the first coupling feed port 223 and the second coupling feed port 224 form a phase gradient of 90°.

[0039] Among them, Figure 4 As shown, the coupling feed port is an I-shaped, and the two horizontal lines 228 of the I-shaped correspond to the inner ring 211 and the outer ring 212 of the radiation unit 21 respectively. The length of the vertical line 229 of the I-shaped is the distance between the inner ring 211 and the outer ring 212, wherein the two horizontal lines 228 of the first coupling feed port 223 correspond to Figure 2 and Figure 3 In section A, the second coupling feed port 224 corresponds to Figure 2 and Figure 3 Part B in.

[0040] Thus, the first output branch line 221 and the second output branch line 222 of the branch line coupler generate circularly polarized radiation on the radiation unit 21 by coupling feeding with the first coupling feeding port 223 and the second coupling feeding port 224 with two phase gradients of 90° on the coupling feeding port.

[0041] The radiation unit 21 needs to have dual-frequency characteristics for radiating two frequency bands, and the feeding network 22 also needs to provide the required phase gradient in both frequency bands, which is usually 90°. The reader antenna 20 disclosed in the present invention can achieve dual-frequency operation under the condition of a feeding network 22, and can achieve circular polarization radiation in each frequency band.

[0042] Specifically, the square structure 227 is a rectangular structure, and the first output branch 221, the second output branch 222, the first input branch 225, and the second input branch 226 are respectively led out from the four vertices of the square structure 227. Among them, the first output branch 221 is adjacent to the second output branch 222 and is located at one end of the square structure 227 (such as Figure 4 The first input branch 225 is adjacent to the second input branch 226 and is located at the other end of the square structure 227 (as shown in FIG. Figure 4 The first input branch line 225 and the first output branch line 221 are located on one side of the square structure 227 (as shown in FIG. Figure 4 upper side shown).

[0043] In addition, the first output branch 221, the first input branch 225 and the second input branch 226 are parallel. The second output branch 222 includes a first line 2221 and a second line 2222, the second output branch 222 is an integrated branch, the first line 2221 is parallel to the first output branch 221, and the second line 2222 is perpendicular to the first line 2221, that is, perpendicular to the first output branch 221. The vertical line 229 of the first coupled feeding port 223 and the second coupled feeding port 224 are perpendicular to the first output branch 221 and the second line 2222 of the second output branch 222, respectively. Further, the impedance of the first input branch 225, the second input branch 226, the first output branch 221 and the second output branch 222 is Z0, which is usually equal to 50Ω.

[0044] Furthermore, if Figure 1 As shown, the Zigbee module 60 is electrically connected to the processing terminal 50. The Zigbee module 60 is used to wirelessly receive the data signal collected and transmitted by the reader 30, and transmit the data signal to the processing terminal 50 for data processing in a wired or wireless manner.

[0045] Among them, the Zigbee module 60 is a new technology for deploying wireless sensor networks, which belongs to a communication protocol and can perform short-distance, low-rate wireless data transmission. In some other embodiments, other wireless communication protocols can also be used between the processing terminal 50 and the reader 30, which are not listed here one by one.

[0046] It is further understood that the terms "first", "second", etc. are used to describe various structures, but these structures should not be limited to these terms. These terms are only used to distinguish structures of the same type from each other, and do not indicate a specific order or importance. In fact, the expressions "first", "second", etc. can be used interchangeably. For example, without departing from the scope of the present disclosure, the first output branch 221 can also be referred to as the second output branch 222, and similarly, the second output branch 222 can also be referred to as the first output branch 221.

[0047] It can be further understood that, unless otherwise specified, “connection” includes a direct connection without other components between the two, and also includes an indirect connection with other components between the two.

[0048] It is further understood that, although the operations are described in a specific order in the drawings in the embodiments of the present disclosure, it should not be understood as requiring the operations to be performed in the specific order shown or in a serial order, or requiring the execution of all the operations shown to obtain the desired results. In certain environments, multitasking and parallel processing may be advantageous.

[0049] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the following scope of rights.

[0050] It should be understood that the present disclosure is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the scope of the appended claims.

Claims

1. A RFID-based wireless passive temperature measurement system (100) for a bearing, characterized in that: include: A temperature sensor (10) comprises a sensor antenna (11), wherein the sensor antenna (11) is a linearly polarized antenna; as well as A reader antenna (20) is connected to the temperature sensor (10) for radiating radio frequency signals; Wherein, the temperature sensor (10) is fixed to the bearing (70), and the reader antenna (21) is a dual-frequency dual circular polarization antenna.

2. The RFID-based wireless passive temperature measurement system (100) for bearings according to claim 1, characterized in that: The reader antenna (20) comprises: The radiation unit (21) comprises a double ring structure consisting of an inner ring (211) and an outer ring (212); A feeding network (22) is arranged below the radiating unit (21) and feeds the radiating unit (21) by coupling feeding; The inner ring (211) is used to radiate electromagnetic waves of 915 MHz, and the outer ring (212) is used to radiate electromagnetic waves of 860 MHz.

3. The RFID-based wireless passive temperature measurement system (100) for bearings according to claim 2, characterized in that: The inner ring (211) and the outer ring (212) are double circular ring structures or double-sided ring structures.

4. The RFID-based wireless passive temperature measurement system (100) for bearings according to claim 2, characterized in that: The feed network (22) comprises: A branch line coupler comprising a first output branch line (221) and a second output branch line (222); A coupled feeding port, comprising a first coupled feeding port (223) and a second coupled feeding port (224), wherein the first coupled feeding port (223) is connected to the first output branch line (221), and the second coupled feeding port (224) is connected to the second output branch line (222), and the first coupled feeding port (223) and the second coupled feeding port (224) form a phase gradient of 90°, The coupling feed port is in the shape of an I-shape, the two horizontal lines (228) of the I-shape respectively correspond to the inner ring (211) and the outer ring (212) of the radiation unit (21), and the length of the vertical line (229) of the I-shape is the distance between the inner ring (211) and the outer ring (212).

5. The RFID-based wireless passive temperature measurement system (100) for bearings according to claim 4, characterized in that: The second output branch (222) comprises: a first line (2221) parallel to the first output branch line (221); and a second line (2222), perpendicular to the first line (2221), The vertical lines (229) of the first coupling feeding port (223) and the second coupling feeding port (224) are respectively perpendicular to the first output branch line (221) and the second line (2222) of the second output branch line (222).

6. The RFID-based wireless passive temperature measurement system (100) for bearings according to claim 5, characterized in that: The branch line coupler further includes: A first input branch line (225) parallel to the first output branch line (221); A second input branch line (226) parallel to the first output branch line (221); A square structure (227), wherein the first output branch line (221), the second output branch line (222), the first input branch line (225) and the second input branch line (226) are respectively led out from four vertices of the square structure (227).

7. The RFID-based wireless passive temperature measurement system (100) for bearings according to claim 1, characterized in that: The sensor antenna (11) is a patch antenna comprising a high dielectric constant material.

8. The RFID-based wireless passive temperature measurement system (100) for bearings according to claim 1, characterized in that: Also includes: Reader (30); A coaxial cable (40) for electrically connecting the reader (30) and the reader antenna (20); Processing terminal (50); as well as A Zigbee module (60) is electrically connected to the processing terminal (50), and the Zigbee module (60) is used to wirelessly receive data information collected by the reader (30) and transmit it to the processing terminal (50).

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