Bolt connection state monitoring device and method based on passive radio frequency identification

Abstract

The invention discloses a passive radio frequency identification-based bolt connection state monitoring device and method, and belongs to the field of spaceflight, and the device comprises a monitoring device, an RFID reader and an upper computer. The monitoring device is provided with an ID and is installed corresponding to the paired bolts and nuts to be monitored. The lower end of a shell of the monitoring device is open and is coaxially fixed to a nut, and the tail end of a screw of a bolt extends into an inner cavity of the shell. An inductance coil is packaged on the side wall of an inner cavity of the shell, the RFID module is fixed to the top of the shell, and the two ends of the coil are connected into a circuit of the RFID module to form a closed loop. The electric signal change generated when the nut rotates relative to the bolt is sensed through the coil, and bolt loosening information is obtained. The RFID module is used for monitoring electric signals in real time, the upper computer is used for issuing monitoring commands and processing data, and the RFID reader is used for establishing two-way information communication between the RFID module and the upper computer. The problem of simultaneous monitoring of the connection states of a plurality of bolts under the working conditions that the bolts are relatively small in size and relatively dense in spaceflight satellites and the installation space of a monitoring device is very limited is solved.

Description

Technical Field

[0001] The present invention belongs to the field of aerospace, and in particular relates to a bolt connection state monitoring device and method based on passive radio frequency identification, which is used to monitor whether the bolt connection state in a satellite structure changes and the position and degree of the change. Background Art

[0002] Considering the differences in component materials and the processing and disassembly procedures, there are often multiple components in a space satellite that are connected by bolts to form an integral structure. During the test, the satellite structure will be subjected to dynamic loads such as vibration and impact, and the state of the bolt connection is prone to change, which may be due to irregular structural deformation or due to faults such as looseness or cracks. Changes in the state of the bolt connection will seriously damage the integrity and reliability of the satellite structure, affect the normal operation of the internal precision instruments, or cause serious problems such as failure and damage of the satellite structure. Therefore, it is very necessary to monitor the state of the bolt connection in the satellite structure in real time (changes, location and degree), and take timely protection and control measures to avoid structural failure and damage.

[0003] In order to monitor the state of bolt connections, domestic and foreign scholars have proposed monitoring equipment and methods based on strain gauges, elongation, vibration, ultrasound and impedance. Compared with these wired communication equipment and methods, equipment and methods based on wireless radio frequency identification (RFID) have received more extensive attention and application. RFID uses radio signals to identify specific targets and read and write related data without establishing mechanical or optical contact between the identification system and the specific target. RFID has significant advantages such as fast recognition speed, large data capacity, long service life and wide application range.

[0004] In the prior art, passive RFID-based bolt connection status monitoring mainly involves installing a device integrated with looseness detection and RFID wireless communication modules on the bolts and nuts. This technical solution has the following shortcomings:

[0005] (1) The monitoring end of the bolt connection status monitoring device includes a fixed component and a rotating component. The connection status is determined by monitoring the relative rotation of the fixed component and the rotating component. The number of parts is large, the structure is complex, and the installation process is increased. The fixed component and the rotating component are exposed to the outside without casing protection and are easily affected by the external environment, resulting in inaccurate monitoring information or device failure.

[0006] (2) Bolt connection status monitoring equipment is mainly used for bolts in locomotives, railways, bridges and towers. The monitoring device is relatively large and complex in structure. Components such as circuit boards and RFID chips are installed on the side of the device, making the overall lateral size of the device large. It is only suitable for application scenarios where the open area around the bolt is large enough. It is mostly used for single bolt monitoring and is not suitable for simultaneous installation and monitoring of multiple bolts at a close distance. The monitoring equipment as a whole does not consider the solution of simultaneous monitoring of multiple bolts. However, the bolts in aerospace satellites are relatively small and densely packed. The installation space of the monitoring device is very limited, and it is often necessary to monitor multiple bolts simultaneously. Summary of the invention

[0007] Technical issues to be solved:

[0008] In order to avoid the shortcomings of the prior art, the present invention provides a bolt connection status monitoring device and method based on passive radio frequency identification to solve the problems that the existing monitoring equipment has many monitoring end components, complex structure installation, and large size that is not suitable for simultaneous installation and monitoring of multiple bolts at close range.

[0009] The technical solution of the present invention is: a bolt connection state monitoring device based on passive radio frequency identification, including a monitoring device, an RFID reader and a host computer;

[0010] The monitoring device is installed one-to-one with the pairs of bolts and nuts to be monitored on the satellite, and each monitoring device is provided with an ID; the monitoring device includes an RFID module, a housing and an inductor coil;

[0011] The shell is a hollow shell with an opening at the lower end, and the open end is coaxially sleeved on the nut of the bolt to be tested and fixedly connected to the nut; the tail end of the screw rod of the bolt to be tested extends into the inner cavity of the shell;

[0012] The inductor coil is wrapped and packaged on the side wall of the inner cavity of the shell, and its two ends are connected to the circuit of the RFID module to form a closed loop. The inductor coil is used to sense the electrical signal generated when the nut rotates relative to the bolt;

[0013] The RFID module is fixed on the top of the housing and is connected to the RFID reader by wireless communication; the RFID reader is connected to the host computer by wired electrical connection;

[0014] Among them: the RFID reader is used to establish two-way information communication between the RFID module and the host computer; the RFID module is used to read the current signal in the closed loop, and transmit the read current signal and the monitoring device ID to the host computer through the RFID reader; the host computer is used to send a monitoring command to the RFID module through the RFID reader, and perform data processing on the feedback current signal and ID.

[0015] A further technical solution of the present invention is: the RFID module includes an RFID circuit, an RFID chip and an RFID antenna, and the RFID circuit, the RFID chip and the RFID antenna are electrically connected and packaged to form the RFID module; the two ends of the inductor coil are connected to the RFID circuit to form a closed loop with the RFID chip.

[0016] A further technical solution of the present invention is: the ID is set on an RFID chip of the monitoring device.

[0017] A further technical solution of the present invention is that the RFID module and the housing are packaged as a whole.

[0018] A further technical solution of the present invention is: the shell is prismatic, matching the radial outer contour shape and size of the nut of the bolt to be tested, and the opening at the lower end of the shell is tightly fitted with the outer wall of the nut; the axial inner cavity size of the shell is sufficient to allow the bolt rod passing through the nut to be accommodated in the cavity.

[0019] A method for simultaneously monitoring multiple bolts in a space satellite using the bolt connection status monitoring device based on passive radio frequency identification comprises the following steps:

[0020] Step 1: Install the monitoring device:

[0021] Determine the positions of the bolts to be monitored simultaneously on the assembled satellite structure, determine the nut size of each bolt to be monitored and the length of the bolt rod exposed from the nut, select a monitoring device with matching specifications for each bolt to be monitored, and install it;

[0022] Step 2: Monitoring equipment debugging and value initialization:

[0023] Connect the RFID reader to the host computer, set the number and location of monitoring devices on the software side of the host computer, and mark the ID corresponding to each location;

[0024] The host computer software starts the initialization mode, the host computer reads the initial value of each monitoring device, and initializes it to 00%, forming a preliminary visual interface;

[0025] Step 3: Monitor equipment operation and visualize results:

[0026] The host computer software starts the real-time monitoring mode, and the ID of each monitoring device and the loosening results of the monitored bolts are viewed in real time through the software end; specifically:

[0027] Step 3.1, the host computer sends a monitoring command to the RFID reader;

[0028] Step 3.2, the RFID reader receives the monitoring command and converts it into a radio frequency signal and sends it to each monitoring device;

[0029] Step 3.3, the RFID module of each monitoring device receives the radio frequency signal from the RFID reader; its RFID chip obtains the activation instruction and starts real-time monitoring to read the current signal of the current circuit; each RFID module transmits the real-time read current signal and its own ID to the host computer through the RFID reader;

[0030] Step 3.4: The upper computer software compares the current value corresponding to each ID obtained with the initial value of the corresponding ID in step 2 to determine whether the connection state of the bolt corresponding to the ID has changed, and displays it visually.

[0031] A further technical solution of the present invention is: the initialization in step 2 includes the following steps:

[0032] Step 2.1, the host computer sends the initial connection status monitoring command of all the bolts to be monitored to the RFID reader;

[0033] Step 2.2, the RFID reader receives the command and converts it into a radio frequency signal and transmits it to the RFID module of the corresponding ID;

[0034] Step 2.3, the RFID module that receives the radio frequency signal in step 2.2 converts the current information in the closed loop and its own ID into a radio frequency signal and sends it to the RFID reader;

[0035] Step 2.4: The RFID reader converts all the signals obtained in step 2.3 into digital signals and transmits them to the host computer, which then performs initialization and calibration.

[0036] A further technical solution of the present invention is: the visual display displays the looseness status of the monitored bolt in percentage to show the degree of bolt looseness. The larger the percentage, the more serious the looseness; the visual display also displays the corresponding ID to determine the position of the loose bolt.

[0037] A further technical solution of the present invention is that the visual display also includes displaying the looseness status of the monitored bolts in different colors, and the darker the color, the greater the degree of looseness of the bolt.

[0038] Beneficial Effects

[0039] The beneficial effects of the present invention are as follows: the bolt connection state monitoring device based on passive radio frequency identification provided by the present invention has a simple structure. The monitoring device as the monitoring end only includes a shell installed on the nut, an inductor coil encapsulated in the shell, and an RFID module coaxially encapsulated on the top of the shell and integrally formed with the shell. The entire monitoring device is tightly matched with the nut. When the connection state between the bolt and the nut changes, the monitoring device rotates with the nut, and the length of the bolt rod in the induction coil changes along the axial direction, causing changes in the inductance and current in the circuit where the coil is located. The changed electrical signal is read and processed by the RFID chip, and transmitted to the host computer through the RFID reader. By comparing with the electrical signal value of the initial state, the connection status information of the bolt to be tested can be obtained.

[0040] The RFID module in the monitoring device of the present invention is installed in the axial direction of the shell, which will not increase the size of the shell side wall, so that the lateral size of the monitoring device can be close to the radial outer dimension of the nut, saving space, and is suitable for simultaneous installation and monitoring of multiple bolts in dense bolt connection scenarios.

[0041] The bolt rod and the inductor coil of the present invention are both enclosed in a shell, and the shell is sleeved on the outer wall of the nut, so that the entire process of induction caused by the displacement of the bolt is not affected by the external environment, and the monitoring stability is good.

[0042] The present invention sets an ID for the RFID module of each monitoring device and realizes simultaneous monitoring of multiple bolt connection conditions and position locking by cooperating with computer software, which is convenient for subsequent maintenance processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is an overall schematic diagram of the device of the present invention;

[0044] Figure 2 This is a schematic diagram of the overall appearance of the monitoring device of the present invention when it is installed;

[0045] Figure 3 This is a schematic diagram of the internal structure of the monitoring device of the present invention when it is installed;

[0046] Figure 4 is a schematic diagram of the device of the present invention;

[0047] Figure 5 This is a visual interface diagram of the device of the present invention.

[0048] Explanation of the accompanying drawings: 1. Monitoring device, 11. RFID module, 111. RFID antenna, 12. Shell, 13. Inductor, 2. RFID reader, 3. Host computer, 4. Bolt, 5. Nut, 6. Satellite body, 7. Satellite connector, A. Loose state of bolt No. 4, B. Loose state of bolt No. 12, C. Loose state of bolt No. 21, D. Loose state of bolt No. 23. DETAILED DESCRIPTION

[0049] The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0050] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0051] Embodiment 1:

[0052] See also Figure 1 This embodiment provides a bolt connection status monitoring device based on passive radio frequency identification. The device is suitable for simultaneous monitoring of multiple bolt connection states in aerospace satellites where the bolts are relatively small and dense and the installation space of the monitoring device is very limited.

[0053] The device includes a monitoring device 1, an RFID reader 2 and a host computer 3. The monitoring device 1 is installed as a test end on a pair of bolts and nuts to be tested. The host computer 3 is used to send monitoring commands and receive and process monitoring data. The RFID reader 2 serves as a communication medium between the monitoring device 1 and the host computer 3 to achieve two-way information exchange between the two. The monitoring device 1 is connected to the RFID reader 2 by wireless communication, and the RFID reader 2 is connected to the host computer 3 by wired electricity. The host computer 3 is specifically a computer.

[0054] Specifically, Figure 1-3 As shown, a plurality of satellite connectors 7 are usually connected to the satellite body 6 by bolt and nut assemblies, and the bolt shank of the bolt 4 sequentially passes through the satellite body 6, the satellite connector 7 and the nut 5, and the satellite connector 7 is fixed by tightening the nut 5. The head of the bolt 4 is located on one side of the satellite body 6, and the tail of the bolt 4 is exposed outside the nut 5. To ensure connection reliability, each satellite connector 7 may be densely provided with multiple groups of bolts and nuts for connection.

[0055] The monitoring device 1 of the present invention is installed one-to-one with the paired bolts and nuts to be monitored on the satellite. Each monitoring device 1 is provided with an ID, and multiple monitoring devices 1 can be installed simultaneously to monitor the bolts 4 to be tested.

[0056] See also Figure 3 The monitoring device 1 includes an RFID module 11, a shell 12 and an inductor 13. The shell 12 is a hollow shell with an opening at the lower end, and its open end is coaxially mounted on the nut 5 of the bolt 4 to be tested, and is fixedly connected to the nut 5, so that the tail end of the screw of the bolt 4 to be tested extends into the inner cavity of the shell 12. The shell 12 matches the radial outer contour shape and size of the nut of the bolt 4 to be tested. In this embodiment, the shell 12 is a hexagonal prism, which is consistent with a conventional hexagonal nut. A snap-fit ​​groove is provided around the inner wall of the lower end opening of the shell 12, which is tightly snap-fitted with the outer wall of the nut 5 and can rotate with the nut 5. The axial inner cavity size of the shell 12 satisfies that the rod of the bolt 4 passing through the nut 5 can be accommodated in the cavity. The material of the shell 12 can be plastic or metal.

[0057] The inductor 13 is wound and packaged on the inner cavity side wall of the housing 12, and its two ends are connected to the circuit of the RFID module 11 to form a closed loop. The inductor 13 is used to sense the electrical signal generated when the nut 5 rotates relative to the bolt 4. When the housing 12 rotates with the nut 5, the axial length of the bolt 4 rod passing through the inductor 13 will change.

[0058] The RFID module 11 is fixed to the top of the housing 12. The RFID module 11 is composed of an RFID circuit, an RFID chip and an RFID antenna package. The RFID circuit, the RFID chip and the RFID antenna 111 are electrically connected to realize information exchange, wherein the RFID chip serves as a control processing unit, the RFID antenna is used to send and receive wireless radio frequency signals, and the RFID circuit forms the internal circuit of the RFID module 11. Both ends of the inductor 13 are connected to the RFID circuit to form a closed loop with the RFID chip.

[0059] The RFID module 11 and the housing 12 are packaged as a whole, and rotate with the housing 12. When the bolt 4 becomes loose and the nut 5 rotates relative to the bolt 4, the entire monitoring device 1 rotates with the nut 5. The ID of each monitoring device 1 is set in the RFID chip of the RFID module 11, which is set at the factory.

[0060] The RFID module 11 is connected to the RFID reader 2 by wireless communication, and the RFID reader 2 is connected to the host computer 3 by wired electrical connection. The RFID reader is used to establish a two-way information communication between the RFID module and the host computer 3, and the RFID reader includes a computer-side RFID circuit, a computer-side RFID chip, and a computer-side RFID antenna. The RFID chip of the RFID module reads the current signal in the RFID circuit connected to the inductor 13, and transmits the read current signal and its own ID to the host computer 3 through the RFID reader 2. The host computer 3 sends a monitoring command to the RFID module 11 through the RFID reader 2, and performs data processing on the current signal and ID fed back.

[0061] Embodiment 2:

[0062] This embodiment provides a method for simultaneously monitoring multiple bolts in a space satellite using the passive radio frequency identification bolt connection status monitoring device of embodiment 1, comprising the following steps:

[0063] Step 1: Install the monitoring device:

[0064] The positions of the bolts 4 to be monitored simultaneously are determined on the assembled satellite structure, the size of the nut 5 of each bolt 4 to be monitored and the length of the bolt rod exposed from the nut 5 are determined, and a monitoring device 1 with matching specifications is selected for each bolt 4 to be monitored and installed.

[0065] Step 2: Monitoring equipment debugging and value initialization:

[0066] The RFID reader 2 and the host computer 3 are connected by cables, and the number and position of the monitoring devices 1 are set on the software end of the host computer 3, and the ID corresponding to each position is marked.

[0067] The main functions of the software in the host computer 3 include initialization and real-time monitoring.

[0068] The upper computer 3 software starts the initialization mode, the upper computer 3 reads the initial value of each monitoring device 1, and initializes it to 00%, forming a preliminary visual interface. The initialization specifically includes the following steps:

[0069] Step 2.1: The host computer 3 sends an initial connection status monitoring command of all the bolts 4 to be monitored to the RFID reader 2.

[0070] Step 2.2: After receiving the monitoring command in step 2.1, the RFID reader 2 modulates the digital signal and converts it into a radio frequency signal, which is then sent to the RFID module 11 of the corresponding ID through the antenna of the RFID reader.

[0071] Step 2.3, the RFID module 11 receives the radio frequency signal of step 2.2, and the RFID chip in the RFID module 11 reads the current information in the circuit at this time, that is, in the initial state, and converts the current information and its own ID into a radio frequency signal, which is sent to the RFID reader 2 by the RFID antenna in the RFID module 11.

[0072] Step 2.4, the RFID reader 2 modulates the current information and corresponding ID information fed back by all RFID modules 11 obtained in step 2.3, converts them into digital signals and transmits them to the host computer 3, which performs initialization calibration. The initial current value of each ID monitoring device 1 obtained by the host computer 3 will be used as a comparison standard for subsequent changes in the current signal of the monitoring device 1.

[0073] Step 3: Monitor equipment operation and visualize results:

[0074] The upper computer 3 software starts the real-time monitoring mode, and the ID of each monitoring device 1 and the loosening result of the monitored bolt 4 can be viewed in real time through the software end visualization interface. Specifically:

[0075] Step 3.1: The host computer 3 sends a real-time monitoring command to the RFID reader 2.

[0076] Step 3.2: The RFID reader 2 receives the monitoring command of step 3.1, converts it into a radio frequency signal and sends it to each monitoring device 1.

[0077] Step 3.3, the RFID antenna of the RFID module 11 of each monitoring device 1 receives the radio frequency signal from the RFID reader 2 in step 3.2, and its RFID chip obtains the activation instruction to start real-time monitoring and read the current signal of the current circuit. Each RFID module 11 modulates the real-time read current signal and its own ID, converts it into a radio frequency signal and sends it to the RFID reader 2.

[0078] Step 3.4: The RFID reader 2 receives the current signal and the corresponding ID fed back by each monitoring device 1, processes all the data, converts them into digital signals and sends them to the host computer 3.

[0079] Step 3.5: The software end of the host computer 3 compares the current value corresponding to each ID obtained with the initial current value corresponding to the ID in step 2, determines whether the connection state of the bolt 4 corresponding to the ID has changed, and visualizes the result.

[0080] See also Figure 4The specific principle of the monitoring device of the present invention is that when the bolt 4 connecting the satellite body and the satellite connector becomes loose, the nut 5 will rotate around the bolt 4, and at the same time drive the shell 12 to rotate around the bolt 4, and the inductor 13 arranged in the shell 12 will rotate around the bolt 4 synchronously, thereby changing the length of the rod of the bolt 4 in the inductor 13 passing axially through the inductor 13, thereby changing the inductance and current of the circuit in the RFID module 11, and the RFID chip in the RFID module 11 reads the current signal in the circuit and feeds it back to the host computer 3 together with the ID. The host computer 3 compares the received current signal with the signal value initially calibrated with the corresponding ID through its own software to determine whether the connection state of the bolt 4 has changed.

[0081] See also Figure 5 In this embodiment, the monitoring device 1 for each ID is set to 00% during initialization calibration, and the looseness of the monitoring bolt 4 is displayed as a percentage. The larger the percentage, the more serious the looseness. The visual display simultaneously displays the corresponding ID, which can easily and quickly determine the location and degree of looseness. Figure 5 A indicates that the loose state of bolt No. 4 is 00%, and no loosening has occurred; B indicates that the loose state of bolt No. 12 is 10%; C indicates that the loose state of bolt No. 21 is 30%; D indicates that the loose state of bolt No. 23 is 40%. In order to facilitate viewing and make the monitoring results more eye-catching, the present invention also sets color display on the visualization interface, and displays the corresponding percentage values ​​in different colors. The darker the color, the greater the looseness of bolt 4. If it exceeds the set threshold, the monitoring result will be displayed in red, indicating a warning. The threshold setting is determined according to actual use needs, such as being set to 80%.

[0082] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A bolt connection status monitoring device based on passive radio frequency identification, characterized in that: It includes monitoring device, RFID reader and host computer; The monitoring device is installed one-to-one with the pairs of bolts and nuts to be monitored on the satellite, and each monitoring device is provided with an ID; the monitoring device includes an RFID module, a housing and an inductor coil; The shell is a hollow shell with an opening at the lower end, and the open end is coaxially sleeved on the nut of the bolt to be tested and fixedly connected to the nut; the tail end of the screw rod of the bolt to be tested extends into the inner cavity of the shell; The inductor coil is wrapped and packaged on the side wall of the inner cavity of the shell, and its two ends are connected to the circuit of the RFID module to form a closed loop. The inductor coil is used to sense the electrical signal generated when the nut rotates relative to the bolt; The RFID module is fixed on the top of the housing and is connected to the RFID reader by wireless communication; the RFID reader is connected to the host computer by wired electrical connection; Among them: the RFID reader is used to establish two-way information communication between the RFID module and the host computer; the RFID module is used to read the current signal in the closed loop, and transmit the read current signal and the monitoring device ID to the host computer through the RFID reader; the host computer is used to send a monitoring command to the RFID module through the RFID reader, and perform data processing on the feedback current signal and ID.

2. The bolt connection state monitoring device based on passive radio frequency identification according to claim 1 is characterized in that: The RFID module includes an RFID circuit, an RFID chip and an RFID antenna, which are electrically connected and packaged to form the RFID module; the two ends of the inductor coil are connected to the RFID circuit to form a closed loop with the RFID chip.

3. The bolt connection state monitoring device based on passive radio frequency identification according to claim 2 is characterized in that: The ID is set on the RFID chip of the monitoring device.

4. The bolt connection state monitoring device based on passive radio frequency identification according to claim 1 is characterized in that: The RFID module and the housing are packaged as a whole.

5. The bolt connection state monitoring device based on passive radio frequency identification according to claim 1 is characterized in that: The shell is prismatic and matches the radial outer contour shape and size of the nut of the bolt to be tested. The opening at the lower end of the shell is tightly fitted with the outer wall of the nut; the axial inner cavity size of the shell is sufficient to accommodate the bolt rod passing through the nut.

6. A method for simultaneously monitoring multiple bolts in a space satellite using the bolt connection status monitoring device based on passive radio frequency identification as claimed in claim 3, characterized in that: The following steps are involved: Step 1: Install the monitoring device: Determine the positions of the bolts to be monitored simultaneously on the assembled satellite structure, determine the nut size of each bolt to be monitored and the length of the bolt rod exposed from the nut, select a monitoring device with matching specifications for each bolt to be monitored, and install it; Step 2: Monitoring equipment debugging and value initialization: Connect the RFID reader to the host computer, set the number and location of monitoring devices on the software side of the host computer, and mark the ID corresponding to each location; The host computer software starts the initialization mode, the host computer reads the initial value of each monitoring device, and initializes it to 00%, forming a preliminary visual interface; Step 3: Monitor equipment operation and visualize results: The host computer software starts the real-time monitoring mode, and the ID of each monitoring device and the loosening results of the monitored bolts are viewed in real time through the software end; specifically: Step 3.1, the host computer sends a monitoring command to the RFID reader; Step 3.2, the RFID reader receives the monitoring command and converts it into a radio frequency signal and sends it to each monitoring device; Step 3.3, the RFID module of each monitoring device receives the radio frequency signal from the RFID reader; Its RFID chip receives the activation command and starts real-time monitoring to read the current signal of the current circuit; each RFID module transmits the real-time read current signal and its own ID to the host computer through the RFID reader; Step 3.4: The upper computer software compares the current value corresponding to each ID obtained with the initial value of the corresponding ID in step 2 to determine whether the connection state of the bolt corresponding to the ID has changed, and displays it visually.

7. The method according to claim 6, characterized in that The initialization in step 2 includes the following steps: Step 2.1, the host computer sends the initial connection status monitoring command of all the bolts to be monitored to the RFID reader; Step 2.2, the RFID reader receives the command and converts it into a radio frequency signal and transmits it to the RFID module of the corresponding ID; Step 2.3, the RFID module that receives the radio frequency signal in step 2.2 converts the current information in the closed loop and its own ID into a radio frequency signal and sends it to the RFID reader; Step 2.4: The RFID reader converts all signals obtained in step 2.3 into digital signals and transmits them to the host computer, which then performs initialization and calibration.

8. The method according to claim 6, characterized in that: The visual display will display the looseness status of the monitored bolt in percentage to show the degree of looseness of the bolt. The larger the percentage, the more serious the looseness. The visual display will also display the corresponding ID to determine the location of the loose bolt.

9. The method according to claim 8, characterized in that: The visual display also includes displaying the looseness status of the monitored bolts in different colors, where the darker the color, the greater the degree of looseness of the bolt.

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