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

Abstract

The invention relates to a wireless passive bearing temperature measurement system based on a radio frequency identification (RFID) technology. The wireless passive bearing temperature measurement system comprises a processing terminal; the reader is configured to send data information to the processing terminal; the reader antenna is electrically connected with the reader and is used for transmitting and receiving signals; and the temperature sensor is used for collecting temperature data and sending the temperature data to the reader. Wherein the reader antenna comprises a source antenna and a transmission array, so that wave beams of signals transmitted by the reader antenna are subjected to steering control and aggregation. In the wireless passive bearing temperature measurement system provided by the invention, the reader antenna comprises the transmission array, so that the gain of the reader antenna can be improved, and beam steering control is realized. In addition, the reader antenna and the sensor antenna can adopt patch antennas, so that the reader antenna and the sensor antenna can resist metal interference and can be used in severe environments.

Description

Technical Field

[0001] The present application relates to the field of wireless monitoring technology, and in particular to a wireless passive bearing temperature measurement system based on RFID. Background Art

[0002] Generally, the working state of the device under test (such as a bearing, etc.) can be diagnosed by sensing the temperature, and the temperature measurement system used to diagnose faults can diagnose whether the device under test has a fault by obtaining the temperature data of the bearing. Therefore, a temperature measurement system that can obtain temperature data in real time is needed.

[0003] Known temperature measurement systems include: wired temperature measurement systems, wireless temperature measurement systems with active sensors, and wireless temperature measurement systems with passive sensors. For wired temperature measurement systems, the installation and wiring of the system are relatively complicated. For active sensors, they include batteries, and when the batteries are exhausted, they need to be replaced before they can continue to be used, or a self-powered module needs to be designed. Due to the need for a battery module, the sensor occupies a large space, which may have an impact on the device being measured, and the cost is very high.

[0004] For passive sensors, this type of sensor has a longer service life, but at the same time, due to the lack of a power supply module, the sensor is more sensitive and more susceptible to environmental influences. For example, the factory environment in the raw material industry is extremely harsh, full of oil, and works under a large amount of water vapor. In addition, there are multiple bearings on multiple raw material machines, which means that multiple temperature measurement points are required. In order to meet the temperature measurement requirements, multiple reader antennas and multiple readers may be required, which will increase the complexity of the temperature measurement system structure and manufacturing costs. Summary of the invention

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

[0006] According to an embodiment of the present application, the present application provides a wireless passive bearing temperature measurement system based on radio frequency identification technology (RFID), which includes: a processing terminal, a reader, a reader antenna, and multiple temperature sensors. The reader is configured to send data information to the processing terminal; the reader antenna is electrically connected to the reader and is used to send and receive signals; the temperature sensor is used to collect temperature data and send it to the reader. Among them, the reader antenna includes a source antenna and a transmission array, so that the beam of the signal emitted by the reader antenna is steered and focused; the reader antenna is configured to send and receive signals to multiple temperature sensors.

[0007] In some embodiments, the transmission array includes a plurality of phase control units arranged in an array, and each phase control unit is provided with a radio frequency element.

[0008] In some embodiments, the RF element is a PIN diode or a varactor diode.

[0009] In some embodiments, the transmission array further comprises a microcontroller for controlling the radio frequency element to control the phase change of the beam of the signal transmitted by the reader antenna.

[0010] In some embodiments, the source antenna is one of a horn antenna, a patch antenna, and a patch array antenna.

[0011] In some embodiments, the source antenna is a 2x2 patch array antenna.

[0012] In some embodiments, the sensor antenna in the temperature sensor is a patch antenna.

[0013] In some embodiments, the patch antenna in the temperature sensor is made of a high dielectric constant material.

[0014] In some embodiments, the temperature sensor is fixed to the inner wall of the inner ring or the outer wall of the outer ring of the bearing, or the end faces of the inner ring and the outer ring, and rotates with the bearing.

[0015] In some embodiments, the wireless passive bearing temperature measurement system further includes: a Zigbee module connected to the terminal, and the Zigbee module is used to wirelessly receive the data information collected by the reader and transmit it to the processing terminal.

[0016] The technical solution provided by the embodiments of the present application may include the following beneficial effects: through the wireless passive bearing temperature measurement system of the present application, the reader antenna includes a transmission array, which can improve the gain of the reader antenna and realize beam steering control. In addition, the temperature measurement system is a wireless passive system, so the temperature sensor can omit the power supply module, saving the volume of the temperature sensor. In addition, the reader antenna and the sensor antenna can adopt patch antennas, so they can be resistant to metal interference and can be used in harsh environments. Moreover, a reader antenna in the wireless passive bearing temperature measurement system provided by the present application can send and receive signals to multiple temperature sensors, without the need for multiple reader antennas to correspond one-to-one with multiple temperature sensors, thereby simplifying the system structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A schematic diagram of a wireless passive bearing temperature measurement system based on RFID according to an embodiment of the present application is shown;

[0019] Figure 2 (a) shows a schematic diagram of the structure of a reader antenna according to an embodiment of the present application;

[0020] Figure 2 (b) shows a front view of a transmission array according to an embodiment of the present application;

[0021] Figure 3 A schematic diagram of a source antenna according to an embodiment of the present application is shown;

[0022] Figure 4 A curve diagram showing the relationship between the angle and gain of the beam of the source antenna according to an embodiment of the present application is shown;

[0023] Figure 5 (a) and Figure 5 (b) is a schematic diagram showing the principle of beam steering and focusing of a signal transmitted by a reader antenna according to an embodiment of the present application;

[0024] Figure 6 An equivalent circuit diagram of a radio frequency element according to an embodiment of the present application is shown;

[0025] Figure 7 (a) shows the beam of the reader antenna according to an embodiment of the present application. Figure 5 (b) is a graph of the relationship between the angle and gain in the XOZ plane; and

[0026] Figure 7 (b) shows the beam of the reader antenna according to an embodiment of the present application. Figure 5 (b) is a graph showing the relationship between the angle and gain on the YOZ plane. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the embodiment of the present application clearer, the technical scheme of the embodiment of the present application will be clearly and completely described below in conjunction with the drawings of the embodiment of the present application. Obviously, the described embodiment is a part of the embodiment of the present application, not all of the embodiments. Based on the described embodiment of the present application, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of this application.

[0028] According to an embodiment of the present application, a wireless passive bearing temperature measurement system based on RFID is provided. The wireless passive bearing temperature measurement system is used to monitor the temperature data of the device under test during operation to diagnose the device under test. For example, the wireless passive bearing temperature measurement system can, but is not limited to, monitor the temperature data of the bearing during operation.

[0029] Figure 1 A schematic diagram of an RFID-based wireless passive bearing temperature measurement system according to an embodiment of the present application is shown. Figure 2 (a) shows a schematic structural diagram of a reader antenna 3 according to an embodiment of the present application; Figure 2 (b) shows a front view of the transmission array 32 according to an embodiment of the present application. Figure 1 , 2 As shown in (a) and 2(b), the wireless passive bearing temperature measurement system includes: a processing terminal 1, a reader 2, a reader antenna 3 and a plurality of temperature sensors 4. The reader 2 is configured to send data information to the terminal 1; the reader antenna 3 is connected to the reader 2 through a coaxial line and is used to send and receive signals; and the reader antenna 3 is configured to send and receive signals to a plurality of temperature sensors 4; the temperature sensor 4 is used to collect temperature data and send it to the reader antenna 3. The reader antenna 3 includes a source antenna 31 and a transmission array 32, and the beams of the signal emitted by the source antenna 31 in each direction are shaped into directional beams through the transmission array 32, so that the beam of the signal emitted by the reader antenna 3 is subject to steering control and gain.

[0030] The basic working principle of the RFID-based wireless passive bearing temperature measurement system is as follows: the reader 2 sends a radio frequency signal of a specific frequency through the reader antenna 3. When the electronic tag from the temperature sensor 4 enters the effective working area, an induced current is generated, thereby obtaining energy and being activated, so that the electronic tag transmits its own encoded information through the sensor antenna; the reader antenna 3 receives the modulated signal sent from the tag, which is transmitted to the signal processing module of the reader 2 via the reader antenna 3. After demodulation and decoding, the valid information is transmitted to the processing terminal 1 for related processing; the processing terminal 1 identifies the identity of the tag according to logical operations, and diagnoses the bearing based on the received temperature data information.

[0031] Specifically, the temperature sensor 4 can be fixed to the inner wall of the inner ring of the bearing or the outer wall of the outer ring, or the end faces of the inner ring and the outer ring, and rotate with the bearing. The multiple temperature sensors 4 can be evenly arranged in the circumferential direction of the bearing. The temperature sensor 4 includes a temperature measuring chip and a sensor antenna (not shown in the figure), and the temperature measuring chip is integrated on the sensor antenna.

[0032] The temperature sensor 4 is a wireless passive sensor. Compared with an active sensor, it does not require an additional battery or cable to power the temperature sensor 4, and reduces the use of cables and avoids complicated wiring, so it is more suitable for the working environment of the bearing. 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, is easy to install, and does not need to worry about running out of power, avoiding frequent battery replacement.

[0033] Furthermore, the reader antenna 3 is wirelessly connected to the sensor antenna. The reader antenna 3 is used to radiate or transmit radio frequency signals. The reader antenna 3 transmits a radio frequency signal (also known as electromagnetic wave, radio wave) energy of a specific frequency to the temperature sensor 4 to drive the temperature sensor 4 to send out its internal signal or data.

[0034] Through the wireless passive bearing temperature measurement system of the present application, the reader antenna includes a transmission array 32, which can improve the gain of the reader antenna 3 and realize beam steering control. In addition, the temperature measurement system is a wireless passive system, so the temperature sensor can omit the power supply module, saving the volume of the temperature sensor. In addition, the reader antenna and the sensor antenna can use patch antennas, so they can be resistant to metal interference and can be used in harsh environments. Moreover, a reader antenna in the wireless passive bearing temperature measurement system provided by the present application can send and receive signals to multiple temperature sensors without the need for multiple reader antennas to correspond one-to-one with multiple temperature sensors, which simplifies the system structure and saves space.

[0035] The sensor antenna 4 generates an induced current by receiving the radio frequency signal emitted by the reader antenna 3, 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 3 through the sensor antenna 4.

[0036] Through the wireless passive bearing temperature measurement system of the present application, the reader antenna 3 includes a transmission array 32, which can improve the gain of the reader antenna 3 and realize beam steering control. Among them, the high-gain reader antenna 3 is conducive to overcoming the influence of harsh environment; and the beam steering control by the transmission array 32 can enable a reader antenna 3 to send and receive signals to multiple temperature sensors 4, without the need for multiple reader antennas to correspond to multiple temperature sensors 4 one by one, so that the system structure is more simplified and space can be saved.

[0037] In some embodiments, the source antenna 31 may be one of a horn antenna, a patch antenna, and a patch array antenna. These types of antennas have certain anti-interference performance against metals.

[0038] In some embodiments, taking the source antenna 31 as a patch array antenna as an example, Figure 3 FIG. 3 shows a schematic diagram of a source antenna 31 according to an embodiment of the present application. Figure 3 As shown, the source antenna 31 may be a 2x2 patch array antenna.

[0039] Through simulation, a curve diagram showing the relationship between the angle of the beam of the source antenna 31 and the gain can be obtained. Figure 4 FIG. 4 shows a curve diagram showing the relationship between the beam angle and gain of the source antenna 31 according to an embodiment of the present application. Figure 4 As shown, the peak gain of the source antenna 31 using a 2x2 patch array antenna is about 8dBi. Through simulation, the 2x2 patch array antenna has a good gain effect. Of course, other numbers of patch array antennas can also be used, and this application does not limit this.

[0040] Figure 5 5(a) and 5(b) are schematic diagrams showing the principle of beam steering and focusing of the signal transmitted by the reader antenna 3 according to an embodiment of the present application. Figure 2 As shown in (a), 2(b), 5(a) and 5(b), in some embodiments, the transmission array 32 includes a plurality of phase control units 32a arranged in an array, and each phase control unit 32a is provided with a radio frequency element. The source antenna 31 is arranged behind the transmission array 32, and the source antenna 31 transmits a beam through a plurality of phase control units 32a, and each phase control unit 32a respectively steers the beam at the corresponding position to a corresponding angle, so as to shape the beam of the signal emitted by the source antenna 31, so that the signal beam is oriented in a certain direction.

[0041] Specifically, see Figure 5 As shown in (a) and 5(b), assuming that the beam steering angle is (θ, φ), the transmission phase of each phase control unit 32a is:

[0042]

[0043]

[0044]

[0045]

[0046] Among them, f m,n is the distance between the source and the (m, n)th phase control unit, k 0 f m,n (k 0 =2π / (λ 0 )) is the phase of the EM wave reaching the (m)th unit, is a unit vector in the (θ, φ) direction, is the coordinate vector of the (m, n)th phase control unit, so the phase delay of the (m, n)th phase control unit is The transmission phase of each phase control unit can be obtained by formula (1): It is a reference phase used to provide design freedom.

[0047] In some embodiments, the RF element 32a is a PIN diode or a varactor diode. Taking a PIN diode (0 / 1 distribution) as an example, Figure 6 FIG. 4 shows an equivalent circuit diagram of a radio frequency element 32a according to an embodiment of the present application. Figure 6 As shown in Figure 1, the PIN diode exhibits two different circuit characteristics when forward biased and reverse biased. Each PIN diode can be controlled by the DC voltage applied on both sides. When the PIN diode is forward biased, it is equivalent to the resistor R s and inductor L s When the PIN diode is reverse biased, it is equivalent to a resistor R s and capacitor C t After parallel connection with inductor L s The PIN diodes are connected in series. The phase change is controlled by controlling the forward bias and reverse bias of the PIN diodes. The 0 / 1 distribution of multiple PIN diodes is digitally quantized to achieve beam steering control.

[0048] Furthermore, a curve diagram showing the relationship between the angle and gain of the beam of the transmission array 32 can be obtained through simulation. Figure 7 (a) shows the beam of the reader antenna 3 according to an embodiment of the present application. Figure 5 (b) is a graph showing the relationship between the angle and gain on the XOZ plane; Figure 7 (b) shows the beam of the reader antenna according to an embodiment of the present application. Figure 5(b) is a graph showing the relationship between the angle and gain on the YOZ plane. In this simulation, the distance between the source antenna 31 and the transmission array 32 is set to 180 mm, and the 0 / 1 distribution at different angles can be obtained by formula (1). Figure 7 (a) and 7(b) show the simulation results, at various beam steering angles ( Figure 7 (a) and 7(b) show graphs when the beam steering angle θ is 10 degrees, 20 degrees, 30 degrees and 40 degrees), and the gain of the reader antenna 3 is about 12dBi.

[0049] Based on Figure 4 From the simulation results shown, the gain of the source antenna 31 is about 8 dBi, and it can be obtained that the gain of the reader antenna 3 is increased by about 4 dB, so the reader antenna 3 can achieve beam steering control and focusing.

[0050] In some embodiments, the transmission array 32 further includes a microcontroller 33 for controlling the RF element 32 a, for example, controlling the 0 / 1 distribution of the PIN diode to control the phase change of the beam of the signal transmitted by the reader antenna 3 .

[0051] In some other embodiments, the reader antenna 3 may further include a reader antenna housing to prevent foreign matter from entering the interior of the reader antenna 3 .

[0052] In some embodiments, the sensor antenna in the temperature sensor 4 is a patch antenna, which can have a good anti-metal interference effect.

[0053] In some embodiments, the patch antenna in the temperature sensor 4 is made of a high dielectric constant material, so that the temperature sensor 4 can be miniaturized.

[0054] In some embodiments, Figure 1 As shown, the wireless passive bearing temperature measurement system further includes: a Zigbee module 5 , which is electrically connected to the processing terminal 1 , and the Zigbee module 5 is used to wirelessly receive the data information collected by the reader 2 and transmit it to the processing terminal 1 .

[0055] Among them, the Zigbee module 5 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 5 and the reader 2, which are not listed here one by one.

[0056] Through the wireless passive bearing temperature measurement system of the present application, the reader antenna 3 includes a transmission array 32, which can improve the gain of the reader antenna 3 and realize beam steering control. In addition, the temperature measurement system is a wireless passive system, so the temperature sensor 4 can omit the power supply module, saving the volume of the temperature sensor. In addition, the reader antenna 3 and the sensor antenna can use patch antennas, so they can be resistant to metal interference and can be used in harsh environments. In addition, a reader antenna 3 in the wireless passive bearing temperature measurement system provided by the present application can send and receive signals to multiple temperature sensors 4, without the need for multiple reader antennas to correspond one by one to multiple temperature sensors, which simplifies the system structure and saves space.

[0057] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and embodiments are only considered as exemplary, and the true scope and spirit of the present application are indicated by the following scope of rights.

[0058] It should be understood that the present application is not limited to the precise structures 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 application is limited only by the scope of the appended claims.

[0059] Reference numerals list

[0060] 1. Processing terminal;

[0061] 2. Reader;

[0062] 3. Reader antenna; 31. Source antenna; 32. Transmitter array; 32a. Phase control unit;

[0063] 33. Microcontroller;

[0064] 4. Temperature sensor;

[0065] 5.Zigbee module.

Claims

1. A wireless passive bearing temperature measurement system based on radio frequency identification technology, include: Processing terminal (1); A reader (2) configured to send data information to the processing terminal (1); a reader antenna (3) electrically connected to the reader (2) and used for sending and receiving signals; as well as A plurality of temperature sensors (4) for collecting temperature data and sending the temperature data to the reader (2); The invention is characterized in that the reader antenna (3) comprises a source antenna (31) and a transmission array (32), so that the beam of the signal emitted by the reader antenna (3) is steered and controlled and the gain is increased, and one reader antenna (3) is configured to send and receive signals to a plurality of temperature sensors (4).

2. The wireless passive bearing temperature measurement system according to claim 1, It is characterized in that The transmission array (32) comprises a plurality of phase control units (32a) arranged in an array, and each phase control unit (32a) is provided with a radio frequency element.

3. The wireless passive bearing temperature measurement system according to claim 2, It is characterized in that The radio frequency element (32a) is a PIN diode or a varactor diode.

4. The wireless passive bearing temperature measurement system according to claim 2, It is characterized in that The transmission array (32) further comprises a microcontroller (33) for controlling the radio frequency element (32a) to control the phase change of the beam of the signal transmitted by the reader antenna (3).

5. The wireless passive bearing temperature measurement system according to claim 1, It is characterized in that The source antenna (31) is one of a horn antenna, a patch antenna and a patch array antenna.

6. The wireless passive bearing temperature measurement system according to claim 5, It is characterized in that The source antenna (31) is a 2x2 patch array antenna.

7. The wireless passive bearing temperature measurement system according to claim 1, It is characterized in that The sensor antenna in the temperature sensor (4) is a patch antenna.

8. The wireless passive bearing temperature measurement system according to claim 7, It is characterized in that The patch antenna in the temperature sensor (4) is made of a material with a high dielectric constant.

9. The wireless passive bearing temperature measurement system according to claim 1, It is characterized in that The temperature sensor (4) is fixed on the inner wall of the inner ring or the outer wall of the outer ring of the bearing, or the end faces of the inner ring and the outer ring, and rotates with the bearing.

10. The wireless passive bearing temperature measurement system according to claim 1, It is characterized in that Also includes: Zigbee A module (5) is electrically connected to the processing terminal (1), and the Zigbee module (5) is used to wirelessly receive the data information collected by the reader (2) and transmit it to the processing terminal (1).

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