CN110261082A - A kind of RFID label tag and the screw loosening condition monitoring system based on it - Google Patents

Abstract

The invention discloses an RFID tag and a screw loosening state monitoring system based on it; it is applied in the field of screw state monitoring, aiming at the problems of missed detection and false detection in the prior art, the RFID tag structure of the present invention is mainly composed of an antenna and a tag chip. When the chip and the antenna are organically connected, the tag can be accessed through the reader device; the metal screw body is used as a switch-type mechanical structure, which determines the connection between the tag chip and the tag antenna. "Off", that is, when the screw is firm, the tag can be read and can communicate with the reader; when the screw is loose, the chip and the tag antenna will be disconnected, which will cause the communication between the tag and the reader to be interrupted; The switch-type mechanical structure of the present invention can be respectively integrated in the tag antenna or the impedance matching network, and forms a whole with the tag, thereby improving the reliability of the screw detection state.

Description

An RFID tag and a monitoring system for loosening of screws based on it

technical field

The invention belongs to the field of screw state monitoring, in particular to a method and a system for detecting the tightening/relaxing state of a screw through the communication transition between an RFID tag and an RFID reader.

Background technique

Automatically monitoring the mechanical condition of certain structures is becoming increasingly necessary, especially in industrial or vehicular environments. In fact, the loose state of the screw can greatly reduce the reliability of the system, and it can also endanger the safety.

Manual inspection by an operator is a possible solution, with physical marking from the outside, for example, a spiral of colored sticky material can be used to detect the working condition of a screw. However, for large structures, such as the inspection of fixing screws at the rear of a train, manual inspections can take a long time. Another possible solution would be to use a vision system capable of recognizing any physical changes in the screw's position, however, such a system would require comparing the actual state with older images that would have to be saved, which is not very practical for large structures.

The patent US7360435B2 describes the monitoring of bolt tightening by measuring the round-trip time change of the longitudinal wave propagating at the end of the bolt; however, this method is only suitable for the detection of tightened screws, not for the detection of the tightened/loose state of screws.

Patent US0089727A1 describes a device for monitoring the temperature and tightening of the screw, including a temperature detector on the screw head and a tightening sensor. The monitoring system proposed in this patent detects the working state of the screw through a complex sensing system, wherein the sensor The system consists of two parts, the first part is fixedly attached to the screw head and the second part is used for the positioning of the structure of the first part. The device needs to design multiple functional module structures, and the device structure is relatively complicated.

The patent (invention patent application number 201810141225.7) describes that the RFID communication system mainly includes readers and RFID tags. The RFID tag structure is divided into two parts, wherein the first part includes a first coupling circuit; the second part includes a second coupling circuit; when the screw is tightened, the first coupling circuit communicates with the second coupling circuit, indicating that the RFID tag is valid; When the screw is loose, the first coupling circuit and the second coupling circuit are disconnected, and the RFID tag is invalid; however, this detection method may miss or misdetect the screw; the details are as follows:

1) When the screw is loose, according to its disclosed implementation, the two parts through which the screw rod passes may not be separated. At this time, the tag can continue to communicate with the reader normally, and the screw is still detected as a tightened state , there is a problem of missed detection of screws;

2) When the tag is in use, the coupling circuit fixed on the two components is offset, etc. At this time, the tag cannot communicate with the reader normally, and the screw is detected as loose, and the screw will have an error detection state at this time . Therefore there is the problem of screw misdetection in the technical scheme disclosed by the patent.

Contents of the invention

In order to solve the above-mentioned technical problems, the present invention proposes an RFID tag and a monitoring system for loosening of screws based on it. When the screw is firm, the tag can be read and can communicate with the reader; when the screw is loose, the chip and the tag antenna will be disconnected, which will cause the communication between the tag and the reader to be interrupted.

One of the technical solutions adopted in the present invention is: including: a tag chip, a tag antenna, an impedance matching network, and a switch-type mechanical structure, the switch-type mechanical structure is integrated in the tag antenna, and when the switch-type mechanical structure is in a closed state, the RFID tag In the working state; when the switch-type mechanical structure is in the open state, the working state of the RFID tag is interrupted; the switch-type mechanical structure is realized by screws. When the screw is tightened, the switch-type mechanical structure is in the closed state. When the screw is loose, the switch-type mechanical structure The structure is open.

Another technical solution adopted by the present invention is: an RFID tag, including: a tag chip, a tag antenna, an impedance matching network and a switch-type mechanical structure, the switch-type mechanical structure is integrated in the impedance matching network, and the switch-type mechanical structure is In the closed state, the impedance of the tag chip matches the tag antenna; when the switch-type mechanical structure is in the open state, the impedance of the tag chip and the tag antenna does not match; the switch-type mechanical structure is realized by screws, and when the screw is tightened, the switch-type mechanical structure is In the closed state, when the screw is loose, the switch type mechanical structure is in the open state.

One of the implementations of the switch-type mechanical structure includes: a dielectric substrate, a first wire, a second wire, and a screw. The dielectric substrate includes at least a screw hole matching the thread of the screw, and the screw passes through the screw hole. When the screw When the screw is tightened, the first wire and the second wire are connected through the screw head; when the screw is loosened, the first wire and the second wire are in an open circuit state.

The second implementation of the switch-type mechanical structure includes: a first switch contact, a second switch contact, a wire and a screw, the wire is fixed on the screw body, and when the screw is tightened, the first end of the wire and the first The switch contact is connected, and the second end of the wire is connected with the second switch contact; when the screw is loose, the first end of the wire and the first switch contact are in an open circuit state, and the second end of the wire is in an open circuit with the second switch contact state.

The present invention also provides an RFID system for monitoring the loose state of screws, including any one of the above-mentioned RFID tags, and an RFID reader; when the switch-type mechanical structure is in a closed state, the RFID reader and the RFID tag are in a normal communication state; When the switch-type mechanical structure is in the open state, the communication status between the RFID reader and the RFID tag is abnormal.

Beneficial effects of the present invention: the present invention realizes the change of the state of the mechanical switch through the slack of the screw, thus presenting as a communication change between the RFID tag and the RFID reader, so that by monitoring the communication between the RFID tag and the RFID reader The monitoring effect of the communication change on the tightness of the screw in advance; the present invention can not only obtain the tightness of the screw by judging the disconnection of the communication between the RFID tag and the RFID reader; it also affects the impedance matching network through the closing and opening of the switch-type mechanical structure Matching and mismatching, by judging whether the communication between the RFID tag and the RFID reader is normal to obtain the tightness of the screw; the advantages of the present invention are as follows:

1. The detection system of the present invention adopts a complete RFID tag structure, and the switch-type mechanical structure can be integrated into the tag antenna or impedance matching network respectively, without considering factors such as the fixation of the tag structure, which improves the reliability of the screw detection state ;

2. The switch-type mechanical structure makes full use of the screw body. When the screw rotates loosely, the wire connected to the screw body immediately shifts; thus causing the antenna or matching network part of the switch mechanical structure to fail; according to the relationship between the label and the antenna Whether the impedance matches or not, to judge the state of the screw.

Description of drawings

Fig. 1 is the screw loose state detection system based on RFID communication provided by the embodiment of the present invention;

Fig. 2 is a block diagram of a tag chip provided by an embodiment of the present invention;

FIG. 3 is an implementation of the tag chip shown in FIG. 2 provided by an embodiment of the present invention;

FIG. 4 is an implementation of the switch-type mechanical structure provided by the embodiment of the present invention;

Fig. 5 is another implementation of the switch-type mechanical structure provided by the embodiment of the present invention;

Among them, 1 is the RFID reader, 2 is the RFID tag, 11 is the transceiver module of the RFID reader, 12 is the antenna of the RFID reader, 21 is the antenna of the RFID tag, 22 is the tag chip of the RFID tag, and 23 is Impedance matching network, 3 is a switch-type mechanical structure, 4 is a PC, 5 is a screw, 311 is a first wire, 312 is a second wire, 313 is a dielectric substrate, 321 is a first switch contact, 322 is a second switch contact Head, 323 is the third wire.

Detailed ways

In order to facilitate those skilled in the art to understand the technical content of the present invention, the content of the present invention will be further explained below in conjunction with the accompanying drawings.

The system of the present invention is used to detect the state of the fastener. When the fastener is in a fastened state, the RFID chip reader and RFID tag are in a normal communication state; when the fastener is in a loose state, the RFID reader ( That is, the reader in Fig. 1) and the RFID tag communication state are abnormal; the fasteners here can be thread fastening or buckle fastening, and the present embodiment takes thread fastening as an example

The present invention realizes the mechanical structural switch by simulating the screw (or a part of the structural screw head), and the effect on the working state of the RFID chip (tag chip in Fig. 2) is realized to monitor the tightness of the screw, as shown in Fig. 1 The screw loose state detection system based on RFID communication provided by the embodiment includes: an RFID chip, an RFID reader-writer, and a switch-type mechanical structure. When the switch-type mechanical structure is in a closed state, the RFID reader-writer and the RFID tag are in normal communication State; when the switch mechanical structure is in the open state, the communication state between the RFID reader and the RFID tag is abnormal.

The RFID reader/writer 1 is composed of a reader/writer radio frequency transceiver module 11 and a radiation part (antenna) 12 .

PC 5 can be used to manage the whole system.

As shown in Figure 2, it is a block diagram of a tag chip provided by the embodiment of the present invention, the RFID tag 2 includes: an antenna 21, a tag chip 22, an impedance matching network 23 (impedance matching network in Figure 2), and the tag chip 22 includes All the circuit structures required for normal communication also include the switch-type mechanical structure 3 (switch like mechanism in Fig. 2) for detecting the loose state of the screw; the antenna is realized by designing an impedance matching network 23 between the tag chip 22 and the tag antenna 21 Optimum power transmission between 21 and tag chip 22 .

As shown in Figure 3, the switch-type mechanical structure 3 is connected in series between the tag antenna 21 and the impedance matching network 23; The electrical continuity between them (through the impedance matching network), the tag chip 22 can normally receive and respond to the inquiry signal from the RFID reader 1; otherwise, when the screw is loose, the switch-like mechanical structure is in an open state, and the antenna 21 and the The tag chips 22 are isolated and disconnected, so that the tags cannot communicate normally.

The switchable mechanical structure 3 can be integrated into the tag antenna 21 or the impedance matching network 23 respectively. When the switchable mechanical structure 3 is disconnected, the tag chip 22 and the antenna impedance are mismatched, and the tag cannot communicate with the reader normally, thus detecting Get the loose state of the screw.

Two implementations of the switch-type mechanical structure 3 are given in this embodiment:

One of the implementations is shown in FIG. 4, including: a first wire 311, a second wire 312, and a dielectric substrate 313. The dielectric substrate 313 includes at least a screw hole matching the thread of the screw 4, and the screw passes through the screw hole. When the screw 4 is tightened, the first wire 311 and the second wire 312 are connected through the screw head; when the screw is loosened, the first wire 311 and the second wire 312 are disconnected. Specifically, it also includes: the other ends of the first wire 311 and the second wire 312 are respectively connected to the antenna 21 or the impedance matching network 23 . In this embodiment, the first wire 311 and the second wire 312 are fixed on the dielectric substrate 313 by welding, and when the screw is tightened, the first wire 311 and the second wire 312 are strengthened and fixed. When loosening, the electrical connection between the first wire 311 and the second wire 312 will be disconnected.

Another implementation is shown in Figure 5, including: a first switch contact 321, a second switch contact 322 and a third wire 323, the third wire 323 is fixed on the screw body, in this embodiment , the third wire 323 is fixed on the screw head, when the screw is tightened, the first end of the third wire communicates with the first switch contact 321, and the second end of the third wire communicates with the second switch contact 322; when the screw is loose , the first end of the third wire 323 and the first switch contact 311 are in an open circuit state, and the second end of the third wire 323 and the second switch contact 322 are in an open circuit state. Specifically, it also includes: the first switch contact 321 and the second switch contact 322 are respectively connected to the antenna 21 or the impedance matching network 23 .

In the implementation manner shown in FIG. 5 , since the conductive performance of the screw and the metal plane will affect the normal communication function of the tag, the third wire needs to be provided with an isolation coating. The third wire 323 in FIG. 5 has a certain strength, and only when the screw body is loose, displacement will occur, causing the third wire 323 to be disconnected from the first switch contact 321 and the second switch contact 322 .

According to the embodiment shown in Fig. 2 and Fig. 5, the present invention can also directly implement a switch-type mechanical structure on the screw structure to ensure electrical continuity when the screw is tightened, and the structure is isolated and interrupted when the screw is loose; for example, connecting the first The third wire 323 of the switch contact 321 and the second switch contact 322 is fixed on the screw structure. When the screw is tightened, the first end of the third wire communicates with the first switch contact 321, and the second end of the third wire communicates with the second end of the third wire. The two switch contacts 322 are connected to ensure the electrical continuity between the antenna and the tag chip; when the screw is loose, the first end of the third wire 323 and the first switch contact 311 are in an open circuit state, and the second end of the third wire 323 It is in an open circuit state with the second switch contact 322, so that the tag cannot communicate normally.

Those skilled in the art will appreciate that the embodiments described here are to help readers understand the principles of the present invention, and it should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Various modifications and variations of the present invention will occur to those skilled in the art. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of the claims of the present invention.

Claims (10)

1. a kind of RFID label tag characterized by comprising label chip, label antenna, impedance matching network and switching regulator machine Tool structure, the switching regulator mechanical structure are integrated in label antenna, when switching regulator mechanical structure is closed state, RFID label tag It is in running order；When switching regulator mechanical structure is in an open state, RFID label tag working condition is interrupted；The switching regulator machinery knot Structure is realized using screw, and when screw is tightened, switching regulator mechanical structure is closed state, when screw relaxation, switch Formula mechanical structure is in an open state.

2. a kind of RFID label tag according to claim 1, the switching regulator mechanical structure includes: medium substrate, first leads Line, the second conducting wire and screw, the medium substrate include at least the screw hole corresponding with screw, and screw passes through The screw hole, when screw is tightened, first conducting wire is connected to the second conducting wire by head of screw；When screw relaxation, It is in off state between first conducting wire and the second conducting wire.

3. a kind of RFID label tag according to claim 1, the switching regulator mechanical structure includes: first switch contact, Two switch contacts, conducting wire and screw, the conducting wire are fixed on screw ontology, when screw is tightened, conducting wire first End is connected to first switch contact, and conducting wire second end is connected to second switch contact；When screw relaxation when, conducting wire first end with It is in off state between first switch contact, is in off state between conducting wire second end and second switch contact.

4. a kind of RFID label tag characterized by comprising label chip, label antenna, impedance matching network and switching regulator machine Tool structure, the switching regulator mechanical structure are integrated in impedance matching network, when switching regulator mechanical structure is closed state, label Chip and label antenna impedance matching；When switching regulator mechanical structure is in an open state, label chip and label antenna impedance are not Match；The switching regulator mechanical structure is realized using screw, and when screw is tightened, switching regulator mechanical structure is closed state, When screw relaxation, switching regulator mechanical structure is in an open state.

5. a kind of RFID label tag according to claim 4, the switching regulator mechanical structure includes: medium substrate, first leads Line, the second conducting wire and screw, the medium substrate include at least the matched screw hole of screw thread with screw, and screw is worn The screw hole is crossed, when screw is tightened, first conducting wire is connected to the second conducting wire by head of screw；When screw relaxation When, it is in off state between first conducting wire and the second conducting wire.

6. a kind of RFID label tag according to claim 4, the switching regulator mechanical structure includes: first switch contact, Two switch contacts, conducting wire and screw, the conducting wire are fixed on screw ontology, when screw is tightened, conducting wire first End is connected to first switch contact, and conducting wire second end is connected to second switch contact；When screw relaxation when, conducting wire first end with It is in off state between first switch contact, is in off state between conducting wire second end and second switch contact.

7. the RFID system that a kind of monitoring screw loosens state, which is characterized in that include at least: any in claims 1 to 3 RFID label tag described in one claim.

8. the RFID system that a kind of monitoring screw according to claim 7 loosens state, which is characterized in that further include: RFID reader, when switching regulator mechanical structure is closed state, RFID reader and RFID label tag are in communications status；Switching regulator When mechanical structure is in an open state, RFID reader and RFID label tag communications status are interrupted.

9. the RFID system that a kind of monitoring screw loosens state, which is characterized in that include at least: any in claim 4 to 6 RFID label tag described in one claim.

10. the RFID system that a kind of monitoring screw according to claim 9 loosens state, which is characterized in that further include: RFID reader, when switching regulator mechanical structure is closed state, RFID reader and RFID label tag are in normal communication state；It opens When pass formula mechanical structure is in an open state, RFID reader and RFID label tag communications status are abnormal.