RFID tag with switching characteristic, passive instrument based on tag and passive encoder based on tag
By adding a status switch module to the RFID tag, wireless and passive data acquisition and event triggering are realized, which solves the problem that existing technologies cannot directly represent the dynamic changes of the physical world, improves data interaction efficiency and reduces maintenance costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-04-10
AI Technical Summary
Existing RFID tags cannot directly characterize the dynamic changes in the physical world, especially switching actions and continuously changing physical quantities, making it difficult to build complex passive measurement systems.
By adding a status switch module to the traditional passive RFID chip and antenna, the switch status can be directly determined by modulating the return signal, realizing a wireless, passive, wiring-free and power-free digital event trigger.
It enables passive, wireless, wiring-free, and power-free data acquisition, simplifies event detection logic, improves data interaction efficiency, reduces maintenance costs, and is suitable for rotating parts and harsh environments.
Smart Images
Figure CN121835718A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of industrial automation, and relates to radio frequency identification (RFID) technology and data acquisition, in particular to an RFID tag with switching characteristics, a passive instrument and a passive encoder based on the tag, and application in industrial automation and digital twin systems. BACKGROUND
[0002] Under the wave of Industry 4.0, smart manufacturing and Internet of Things (IoT), real-time, efficient and non-missing collection of physical world data is the basis for building digital twins and realizing intelligent decision-making. At present, data collection mainly relies on wired sensors and battery-powered wireless sensor networks (WSN). The wired solution has complex wiring, high cost and poor flexibility; while the battery-powered wireless solution has limited battery life, frequent maintenance and great environmental pressure.
[0003] RFID technology is widely used due to its advantages of being passive, non-contact, fast identification and low cost. However, traditional RFID tags (whether passive or active) mainly store and return a fixed ID or a small amount of static data, and cannot directly represent the dynamic changes of the physical world (such as switching actions, continuously changing physical quantities or precise positions). Although there are RFID tags integrated with sensors (such as temperature sensing tags), they usually focus on single analog measurement and lack efficient and direct capture and reporting mechanisms for simple digital events (such as switches and on-off), making it difficult to build complex passive measurement systems (such as encoders).
[0004] Therefore, there is an urgent need for a solution that can directly and efficiently convert physical state changes (especially switching quantities) into wireless digital signals and extend it to a multifunctional passive acquisition node. SUMMARY
[0005] The present application aims to overcome the shortcomings of the prior art and provide an RFID tag with switching characteristics, providing a digital "event trigger" without wiring and power supply.
[0006] Another object of the present application is to provide a passive instrument and a passive encoder based on the above-mentioned RFID tag, realizing passive and wireless acquisition and transmission of physical switching events, sensor data and position information.
[0007] The first aspect of the present application provides an RFID tag with switch feature. The tag is based on a conventional passive RFID chip and antenna, with an added state switch module. The state of the switch module (e.g. on / off) directly affects the tag's return signal. When querying the tag, an RFID reader can not only read its ID, but also directly determine the instant state of the switch by analyzing the return signal (e.g. different data zone content, specific encoding or reflection characteristic change). This is equivalent to providing a digital "event trigger" for a simple event in the physical world (switch action) without wiring or power supply.
[0008] In one implementation, the RFID tag with switch feature comprises a radio frequency antenna, an RFID chip, an energy harvesting and power management circuit, and a state switch module; the radio frequency antenna and the RFID chip are configured to communicate with an RFID reader wirelessly and receive radio frequency energy; the energy harvesting and power management circuit converts and stores the electrical energy obtained from the radio frequency energy to power the RFID chip; the state switch module is electrically connected to the radio frequency antenna and the RFID chip, and has at least two distinguishable physical or electrical states; the radio frequency antenna and the RFID chip are configured to modulate the response signal returned to the RFID reader according to the current state of the state switch module, so that the RFID reader can distinguish and read the state information of the state switch module.
[0009] In one implementation, the state switch module is one of a mechanical switch, a magnetic switch, a light-controlled switch, or an electronic switch.
[0010] In one implementation, the RFID chip comprises a storage unit for storing a specific identifier or data associated with the switch state.
[0011] The second aspect of the present application provides a passive instrument based on the above-mentioned tag. It integrates one or more sensors (e.g. temperature, pressure sensors) with the RFID tag with switch feature. The sensors are powered by the radio frequency energy collected by the tag. The instrument can report the switch state and sensor measurement value simultaneously or at different times. For example, an instrument on a device can automatically report the start event and the current temperature value when the device is started (the switch is closed).
[0012] In one implementation, the passive instrument comprises the RFID tag with switch feature as described above, and at least one sensor; the sensor is connected to the RFID tag and powered by the energy harvesting and power management circuit; the RFID chip is further configured to collect the measurement data of the sensor and send it to the RFID reader through the radio frequency antenna together with or selectively with the state information of the state switch module.
[0013] In an implementation, the sensor is a temperature sensor, a pressure sensor, a humidity sensor, a vibration sensor, or a proximity sensor.
[0014] In a third aspect, the application provides a passive encoder. It utilizes a plurality of RFID tags with switch features, arranged according to certain encoding rules (such as binary code, Gray code), whose trigger pieces of the switch modules are mechanically coupled with an encoding disk (or ruler) with trigger structure. When the encoding disk rotates or moves, it will change the states of the switch modules of the tags, forming a unique set of binary codes representing the absolute position. The RFID reader reads the set of codes at one time, thus calculating the precise position, without power supply and slip ring, realizing truly passive and wear-free absolute position measurement.
[0015] In an implementation, the passive encoder comprises an encoding disk or ruler and one or more RFID tags with switch features as described above; the encoding disk is provided with trigger structure; the trigger pieces of the state switch modules of the one or more RFID tags are matched with the trigger structure on the encoding disk; when the encoding disk is displaced or rotated, the trigger structure changes the states of one or more of the state switch modules, thus forming a combination of switch states corresponding to the position or displacement, and the combination is read by the RFID reader to decode the position or motion information.
[0016] In an implementation, the trigger structure is a protrusion, a groove, a magnet, or an optical grating; the state switch module is a corresponding micro switch, Hall switch, or photoelectric switch.
[0017] In an implementation, a plurality of the RFID tags are arranged according to the rules of binary code or Gray code, constituting an absolute position encoder.
[0018] Compared with the prior art, the application has the following beneficial effects:
[0019] 1) Completely passive: all devices obtain energy from the radio frequency field of the RFID reader, without the need for a battery or external power supply, with a long life cycle and extremely low maintenance cost.
[0020] 2) Flexible deployment: the wireless nature allows installation location to be free from wiring restrictions, especially suitable for rotating parts, mobile platforms, or harsh environments.
[0021] 3) Efficient data: the switch state as the most direct digital signal can be quickly and reliably identified by the reader, greatly simplifying the logic of event detection.
[0022] 4) High system integration: The switch, sensor, coding function and RFID identification are integrated into one, and multi-dimensional information (ID, status, data, location) can be obtained at a single reading, with high data interaction efficiency with the digital twin system.
[0023] 5) Cost advantage: The structure is relatively simple, and mature RFID technology can be used, with low cost for large-scale application. BRIEF DESCRIPTION OF DRAWINGS
[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.
[0025] Figure 1 The circuit block diagram of the RFID tag with switch characteristics in the first embodiment of the present application.
[0026] Figure 2 The schematic diagram of the passive instrument in the second embodiment of the present application.
[0027] Figure 3 The structural schematic diagram of the passive absolute encoder in the third embodiment of the present application (binary coding example).
[0028] Figure 4 The application scenario diagram of the present application, showing the data interaction of the passive instrument and encoder with the digital twin system on the industrial equipment. DETAILED DESCRIPTION
[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, not all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.
[0030] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.
[0031] It should be noted that: similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.
[0032] In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly used when the product of the present application is used, or the orientation or positional relationship commonly understood by those skilled in the art, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" and the like are only used to distinguish the description and cannot be understood as indicating or implying relative importance.
[0033] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "set", "mount", "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, it can be directly connected, or indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.
[0034] Embodiment one: RFID tag with switching characteristics
[0035] As shown in Figure 1 The present embodiment provides a kind of RFID tag with switching characteristics, which includes radio frequency antenna 101, RFID chip 102, energy collection and power management circuit 103 and a mechanical normally open micro switch 104.
[0036] Radio frequency antenna 101 is used to collect radio frequency energy, and is converted into electrical energy by energy collection and power management circuit 103 and stored.
[0037] RFID chip 102 has readable and writable memory. One end of micro switch 104 is connected to a general input / output (GPIO) pin of chip 102, and the other end is grounded. In the default state (switch is off), the GPIO of RFID chip 102 is pulled high, and its internal logic is set to return the data of storage area A (for example "ID: 001, Status: OFF") when queried by RFID reader. When external force presses micro switch 104 to make it closed, GPIO becomes low. RFID chip 102 detects this change and switches to return the data of storage area B (for example "ID: 001, Status: ON") when queried. RFID reader can know the switch state by parsing the "Status" field in the returned data. Alternatively, the state change can also be realized by changing the backscatter modulation depth and the like.
[0038] Example 2: Passive temperature monitoring instrument
[0039] As shown in Figure 2 , this example provides a passive temperature monitoring instrument, which integrates an RFID tag board 201 as in Example 1, a digital temperature sensor 202 and a magnetic reed switch 203 for equipment start-stop detection. All circuits are powered by the tag board's energy harvesting and power management circuit. The RFID chip is programmed to periodically (e.g. once per second) read the value of the temperature sensor 202 and the state of the magnetic reed switch 203, and write these data into its user memory area. When in the effective field of an RFID reader, the RFID reader can read the data packet in the format of "ID: T_Unit_05, Temp: 25.3°C, Running: YES", realizing the synchronous passive monitoring of state and analog quantity.
[0040] Example 3: Passive absolute position encoder
[0041] As shown in Figure 3 , this example provides a passive absolute position encoder, which includes an RFID tag integrated unit and a rotating encoder disc 301 rotating relative to the RFID tag integrated unit. Four concentric magnetic ring tracks are arranged radially on a rotating encoder disc 301, corresponding to 4-bit binary encoding (0000-1111 representing 0-15, a total of 16 positions). Each track is embedded with a small magnet 302 (representing '1') at a specified sector, and the unembedded part represents '0'. In the fixed RFID tag integrated unit corresponding to the rotating encoder disc 301, an RFID tag 303 integrated with a Hall switch is installed corresponding to each track (i.e. the state switch module is a Hall switch). When the rotating encoder disc rotates, the magnet approaches the Hall switch of the corresponding tag, causing its state to change from '0' to '1'. The ID of the four tags is associated with their bit weight (e.g. 1, 2, 4, 8). An RFID reader can read the switch state of the four RFID tags at the same time (e.g. Tag 1 = ON (1), Tag 2 = OFF (0), Tag 3 = ON (1), Tag 4 = OFF (0)), and the binary code "1010" is obtained by combination, and after decoding, it can be known that the current position is the 10th sector. This design realizes absolute position measurement without contact and without power supply.
[0042] Application scenarios
[0043] As shown in Figure 4As shown, in an intelligent manufacturing production line, the passive absolute position encoder 402 given in embodiment three is installed at the joint of the rotary mechanical arm 401 to monitor the rotation angle. For example, the rotary encoder disc of the passive absolute position encoder 402 is coaxially connected with the output shaft of the joint motor. The RFID tag integrated unit of the passive absolute position encoder 402 is fixedly arranged relative to the joint of the rotary mechanical arm 401, and the RFID tag integrated unit is provided with one RFID tag integrated with a Hall switch corresponding to each track.
[0044] The passive temperature and vibration instrument 403 is installed on the equipment shell. The fixed position RFID reader / writer 404 regularly reads these data and uploads them to the cloud digital twin system 406 through the industrial gateway 405. The digital twin system updates the posture of the virtual mechanical arm and the health status of the equipment in real time, realizes visual monitoring and predictive maintenance. At the same time, when the system discovers temperature abnormalities, it can send instructions to the instrument through the reader / writer through the reverse link to increase the data reporting frequency.
[0045] Therefore, the passive encoder can convert mechanical displacement or angle into a trigger sequence of a switch array to realize passive coding of absolute position or incremental trajectory. The device of the present application does not need external power supply and works through radio frequency energy, can efficiently and reliably collect and transmit physical signals to the upper system or digital twin platform, greatly simplifies the wiring complexity and maintenance cost in the industrial automation, intelligent manufacturing and Internet of Things scenes.
Claims
1. An RFID tag with switching characteristics, characterized in that, include: Radio frequency antenna, RFID chip, energy harvesting and power management circuit, and status switch module; The radio frequency antenna and RFID chip are used to communicate wirelessly with the RFID reader and receive radio frequency energy; the energy harvesting and power management circuit converts and stores the electrical energy obtained from the radio frequency energy to power the RFID chip. The status switch module is electrically connected to the radio frequency antenna and the RFID chip, and has at least two distinguishable physical or electrical states; the radio frequency antenna and the RFID chip are configured to modulate the response signal returned by the status switch module to the RFID reader according to the current state of the status switch module, so that the RFID reader can distinguish and read the status information of the status switch module.
2. The RFID tag with switching characteristics according to claim 1, characterized in that, The status switch module is one of a mechanical switch, a magnetic switch, a light-controlled switch, or an electronic switch.
3. The RFID tag with switching characteristics according to claim 1 or 2, characterized in that, The RFID chip includes a storage unit for storing a specific identifier or data associated with the switch state.
4. A passive instrument, characterized in that, include: The RFID tag with switching characteristics as described in any one of claims 1-3, and at least one sensor; the sensor is connected to the RFID tag and powered by the energy harvesting and power management circuit; the RFID chip is further configured to: collect measurement data from the sensor and transmit it, together with or selectively, the status information of the status switch module through the radio frequency antenna to an RFID reader.
5. The passive instrument according to claim 4, characterized in that, The sensor is a temperature sensor, pressure sensor, humidity sensor, vibration sensor, or proximity sensor.
6. A passive encoder, characterized in that, include: The encoding disk or encoding ruler and one or more RFID tags with switching characteristics as described in any one of claims 1-3; the encoding disk is provided with a trigger structure; the trigger element of the status switch module of the one or more RFID tags cooperates with the trigger structure on the encoding disk; when the encoding disk is displaced or rotated, the trigger structure changes the state of one or more of the status switch modules, thereby forming a switch state combination corresponding to the position or displacement, and the combination is read by an RFID reader to decode the position or motion information.
7. The passive encoder according to claim 6, characterized in that, The triggering structure is a protrusion, a groove, a magnet, or a grating; the status switch module is a corresponding micro switch, Hall switch, or photoelectric switch.
8. The passive encoder according to claim 6 or 7, characterized in that, Multiple RFID tags are arranged according to the rules of binary encoding or Gray code to form an absolute position encoder.
9. A data acquisition and interaction system, characterized in that, include: The system comprises an RFID reader / writer, a passive instrument as described in claim 4 or 5, and / or a passive encoder as described in claims 6-8, and a digital twin system; the RFID reader / writer reads the switch status, sensor data, and / or location information reported by the passive instrument and / or passive encoder, and uploads the information to the digital twin system; the digital twin system updates the status of the virtual model according to the received information, and can send configuration or control commands to the passive instrument and / or passive encoder via the RFID reader / writer.