A remote meter monitoring device and method based on internet of things

Abstract

The application belongs to the technical field of Internet of Things, and discloses a remote instrument monitoring device and method based on Internet of Things, which comprises three parts of a sensing layer, a network layer and an application layer. The sensing layer comprises a controller, a sensor, an NB-Iot wireless transmission module and an actuator. The controller and the sensor, and the controller and the NB-Iot wireless transmission module all adopt serial communication to realize bidirectional transmission of data. The network layer comprises an NB-Iot base station and a OneNet cloud platform. The application adopts the Internet of Things technology, has a communication switching function, can comprehensively consider the required communication mode according to the communication distance, the advantages and disadvantages of a channel, the energy consumption demand and other conditions, can guarantee the reliability of communication to the maximum extent, and reduces information loss and energy waste.

Description

Technical Field

[0001] The present invention belongs to the technical field of Internet of Things, and in particular relates to a remote instrument monitoring device and method based on the Internet of Things. Background Art

[0002] Traditional factories mainly rely on technicians to conduct daily instrument maintenance and inspection based on their experience, or use detectors for inspection, and record the inspection results by hand. This consumes a lot of manpower, is inefficient, cannot provide timely feedback, and is prone to errors, which is extremely detrimental to factory production.

[0003] A small number of smart meters have a single communication mode and only support short-range communication. When some mobile devices (such as robots) are in motion, the signal will be interrupted due to the long distance. Such smart meters rarely have the function of adjusting the communication mode and lack feedback, making it difficult to ensure smooth and reliable communication.

[0004] In response to the above problems, the present invention has designed a new remote instrument monitoring method based on Internet of Things technology. This method can remotely detect multiple instruments at the same time. In addition to allowing on-site staff to see the instrument data in real time, the data can be directly uploaded to the server for real-time monitoring and data storage. It can also dynamically adjust the communication mode according to actual needs, taking into account both communication quality and energy loss. Summary of the Invention

[0005] The purpose of the present invention is to provide a remote instrument monitoring device and method based on the Internet of Things to solve the above technical problems.

[0006] To solve the above technical problems, the specific technical solutions of the present invention for a remote instrument monitoring device and method based on the Internet of Things are as follows:

[0007] A remote instrument monitoring device based on the Internet of Things (IoT) comprises a perception layer, a network layer, and an application layer. The perception layer includes a controller, a sensor, an NB-IoT wireless transmission module, and an actuator. The controller and the sensor, as well as the controller and the NB-IoT wireless transmission module, all communicate via serial ports to achieve bidirectional data transmission. The network layer includes an NB-IoT base station and a OneNet cloud platform. The NB-IoT base station modulates and demodulates data transmitted by the perception layer, encapsulates the data in a network packet format, and forwards it to the OneNet cloud platform via LwM2M. A real-time message forwarding program is deployed on the cloud server for storing the data in a database and a host computer. The OneNet cloud platform issues control instructions to the perception layer via the NB-IoT base station, thereby controlling the actuators of the perception layer. The application layer includes current and voltage display channels for multiple factory instruments after power-on, for viewing real-time data from different devices and controlling the devices. Data for a specified time period is retrieved from the OneNet cloud platform database and generated and output in tables of different formats for local storage. The controller controls the NB-IoT wireless transmission module to communicate with the cloud platform using AT commands via a serial port, and transmits the data to the cloud platform.

[0008] Furthermore, it includes a power supply module, which is responsible for powering the factory equipment and the monitoring device. The controller of the perception layer includes an STM32 main control, which is responsible for receiving the collected data of the terminal and sending the data to the cloud platform through the Internet of Things module after being programmed according to the communication protocol. The NB-Iot wireless transmission module is responsible for wireless long-distance communication between the terminal and the cloud server. The sensor includes a voltage acquisition circuit, a current acquisition circuit and a temperature acquisition circuit. The voltage acquisition circuit is responsible for collecting the instrument voltage value, the current acquisition circuit is responsible for collecting the instrument current value, and the temperature acquisition circuit is responsible for collecting the current ambient temperature value; the OneNet cloud platform receives the detection results and data of the sensor through the NB-Iot wireless transmission module for unified management, and can detect whether the data is abnormal by manually setting the parameter threshold. When the corresponding value exceeds the set threshold, a warning message will be triggered, and the monitoring administrator can be notified by SMS or email.

[0009] Furthermore, the temperature sensor model is PT100, and the controller model is STM32F103VET6.

[0010] Furthermore, the application layer includes an LED screen, which is used to display data collected by the temperature sensor PT100 and the voltage and current collection circuit.

[0011] Furthermore, the application layer includes a client, which is used to view data in real time, retrieve past data, and control factory equipment.

[0012] The present invention also discloses a monitoring method for a remote instrument monitoring device based on the Internet of Things, including a communication switching method, wherein the communication switching method comprises the following steps:

[0013] Step 1: Estimate the current communication distance and determine the default communication mechanism for device initialization based on the initial unlimited communication distance measurement data.

[0014] Step 2: When the device is located at the boundary of the long-distance and short-distance signal communication distance, the controller sends a signal to switch the communication mode according to the signal stability;

[0015] Step 3: The device begins the authentication process by sending an authentication request frame. The authentication request frame is a message sent by the device to inform the new AP of its identity.

[0016] Step 4: The new AP responds to the authentication request by sending an authentication response frame to indicate whether the new AP accepts or rejects the device.

[0017] Step 5: Once the authentication process is successfully completed, the device sends a reassociation request frame to the new AP. Step 6: Finally, the new AP sends a reassociation response frame containing information about whether the device has been accepted or rejected.

[0018] Furthermore, 433M wireless communication is used for short distances, and 3 / 4G and LoRa wireless communication are used for long distances.

[0019] Furthermore, the controller collects measurement data on the digital communication bandwidth of the wireless channel and determines the robot's communication mechanism for each cycle through computational analysis. This process then sends a switching instruction to the controller, setting up two transceivers that independently perform communication tasks in parallel. The specific process for selecting and switching between 433M wireless communication and LoRa wireless communication is as follows:

[0020] Step 1: Estimate and calculate the current communication distance. Based on the initial unlimited communication distance measurement data, determine the default communication mechanism for device initialization at this time. The wireless communication distance calculation formula is expressed as formula (1):

[0021] Los=32.44+20lgD+20lgF(1)

[0022] In formula (1), Los, D, and F correspond to transmission loss, transmission distance, and communication frequency, respectively. When switching the communication mode, the communication distance is estimated based on the calculation results and the communication mode is selected.

[0023] Step 2: When the device is located at the boundary of the long-distance and short-distance signal communication distance, the communication mode of the controller sending the signal is switched according to the signal stability. The calculation formula for extracting the time series signal feature statistics is shown in formulas (2)(3)(4)(5):

[0024]

[0025]

[0026] γ(t,s)=E[(X t -μ t )(X s -μ s )] (4)

[0027]

[0028] Where μ t 、 γ(t, s) and ρ(t, s) are the signal mean, variance, autocovariance, and autocorrelation coefficient, respectively. According to the above calculation results, if the following conditions are met, the time series is wide-stationary. This indicator is used as one of the indicators to measure the stability of wireless signal quality:

[0029] 1. For any t∈T, we have

[0030] 2. For any t∈T, there is EX t =μ, where μ is a constant;

[0031] 3. For any t, s, k∈T, k+st∈T, γ(t, s) = γ(k, k+st).

[0032] Furthermore, before disconnecting from the current AP, the device finds a set of APs that may be associated with it.

[0033] Furthermore, the communication mode switching method is soft switching, which is the switching between different base stations at the same frequency. During the switching process, the mobile station maintains communication links with both the original base station and the new base station until it enters the new base station and measures that the transmission quality of the new base station meets the index requirements, and then disconnects from the original base station.

[0034] The present invention provides a remote instrument monitoring device and method based on the Internet of Things, which has the following advantages:

[0035] The present invention checks the instrument based on mobile Internet of Things technology, eliminating the trouble of meter reading and preventing problems such as missed reading and wrong reading. It uses the MQTT transmission protocol to store data in the cloud server database, and designs PC clients and mobile phone APPs to facilitate enterprises to retrieve and analyze data at any time.

[0036] The present invention adopts Internet of Things technology and has no restrictions on the use distance of the equipment. When employees of some instrument manufacturing companies are on business trips to maintain the company's instruments, they can directly upload the current status of the instruments to the server, making it convenient for the company to detect the current usage of products in the market and optimize the products.

[0037] The present invention can not only upload data to the server, but also control the device through the host computer. It can be deployed in the factory for a long time, so that the device can be turned on at any time on the mobile terminal to detect and monitor the instrument without manpower, greatly reducing labor costs and improving production efficiency.

[0038] At the same time, the present invention can comprehensively consider the currently required communication mode according to conditions such as communication distance, channel quality, energy consumption requirements, etc., and can ensure the reliability of communication to the greatest extent, reduce information loss and energy waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a network architecture diagram of the remote instrument monitoring device based on the Internet of Things of the present invention;

[0040] Figure 2 This is a hardware module diagram of the remote instrument monitoring device based on the Internet of Things of the present invention;

[0041] Figure 3 It is the principle diagram of the microcontroller STM32F103VET6 of the present invention;

[0042] Figure 4 This is a schematic diagram of the voltage and current acquisition circuit of the present invention;

[0043] Figure 5 This is a schematic diagram of the power supply module circuit of the present invention;

[0044] Figure 6 This is a client design diagram of the present invention. DETAILED DESCRIPTION

[0045] In order to better understand the purpose, structure and function of the present invention, the following is a further detailed description of a remote instrument monitoring device and method based on the Internet of Things of the present invention in conjunction with the accompanying drawings.

[0046] like Figure 1 As shown, the network architecture of a remote instrument monitoring device based on the Internet of Things of the present invention includes three parts: a perception layer, a network layer, and an application layer.

[0047] The perception layer includes the controller, sensors, NB-IoT wireless transmission modules, and various actuators. The controller and sensors, as well as the controller and NB-IoT wireless transmission modules, use serial ports to communicate, enabling bidirectional data transmission. The controller uses AT commands via the serial port to control the NB-IoT wireless transmission module to communicate with the cloud platform and transmit data to the cloud platform.

[0048] The network layer includes NB-IoT base stations and the OneNet cloud platform. The NB-IoT base station modulates and demodulates data transmitted by the perception layer, encapsulates it in network packet format, and forwards it to the OneNet cloud platform via LwM2M. A real-time message forwarding program is deployed on the cloud server for storage in a database and on a host computer. The OneNet cloud platform issues control commands to the perception layer through the NB-IoT base station, thereby controlling the actuators in the perception layer.

[0049] Application Layer: Leveraging the API provided by the cloud platform, the application layer provides channels for displaying the current and voltage of multiple factory instruments after power-on, as well as information about the remaining battery level and ambient temperature of the current detection devices. A host computer was developed to view real-time data from various devices, retrieve data for a specified time period from the OneNet cloud platform database, and generate and output tables in various formats for local storage. A mobile app was developed to facilitate mobile data viewing and device control.

[0050] Specifically, a remote instrument monitoring device based on the Internet of Things of the present invention also includes a power supply module, which is responsible for supplying power to factory equipment and the monitoring device. The controller of the perception layer includes an STM32 main control, which is responsible for receiving the collected data of the terminal and sending the data to the cloud platform through the Internet of Things module after programming according to the communication protocol. The NB-Iot wireless transmission module is responsible for wireless long-distance communication between the terminal and the cloud server. The sensor includes a voltage acquisition circuit, a current acquisition circuit and a temperature acquisition circuit. The voltage acquisition circuit is responsible for collecting the instrument voltage value. The current acquisition circuit is responsible for collecting the instrument current value. The temperature acquisition circuit is responsible for collecting the current ambient temperature value. The OneNet cloud platform receives the detection results and data of the sensor through the NB-Iot wireless transmission module for unified management, and can detect whether the data is abnormal by manually setting the parameter threshold. When the corresponding value exceeds the set threshold, a warning message will be triggered, and the monitoring administrator can be notified by SMS or email.

[0051] Hardware design example:

[0052] Take temperature measurement as an example, Figure 2The device, shown here, is an IoT-based remote instrument monitoring device. It includes a PT100 temperature sensor, a voltage and current acquisition circuit, an STM32F103VET6 microcontroller, an NB-IoT wireless transmission module, an LED screen, and a power supply module. The power supply module powers factory equipment and the monitoring device, enabling measurements even when the equipment is powered off. The LED screen displays data collected by the PT100 temperature sensor and the voltage and current acquisition circuit.

[0053] Specifically, the schematic diagram of the microcontroller STM32F103VET6 is as follows Figure 3 As shown in the figure, the chip uses a 32-bit Cortex-M3 core, adopts a 100-pin package, has multiple general IO ports, and also integrates multiple high-precision time controllers, analog-to-digital converters, digital-to-analog converters, asynchronous serial communication controllers and other functional modules. Figure 4 As shown in the figure, the temperature sensor PT100 is a thermistor with a positive temperature coefficient. As the temperature rises, the resistance value of the resistor increases. On the contrary, if the resistance value of the resistor decreases as the temperature rises, it is a thermistor with a negative temperature coefficient. The power supply module circuit designed for the microcontroller STM32F103VET6 in this device and the NB-IOT wireless transmission module is as follows: Figure 5 As shown, the STM32F103VET6 microcontroller contains multiple modules. During its design, the chip also included multiple power inputs to power different modules. This chip integrates both analog and digital circuits, so it includes both analog and digital power supplies. It also has a battery power input for backup in the event of a system power outage.

[0054] Client design example:

[0055] In order to facilitate users to view data in real time and retrieve past data, and control factory equipment, the host computer is designed using Python. Figure 6 As shown,

[0056] The main functions are as follows:

[0057] The left half shows the device ID currently in use and the data measured in real time.

[0058] Send the POST command to NB-IOT to control the switches of eight measurement channels.

[0059] By selecting a time period, you can retrieve database information and export it to local files in different formats.

[0060] Algorithm design example:

[0061] In order to enable the communication terminal to support both long-distance and short-distance communication, this project adopts a reliable seamless switching mechanism for long-distance and short-distance communication, taking the advantages of each communication mechanism so that the switching of the modes can be effectively controlled to ensure the security of data communication. The specific switching process is as follows:

[0062] (1) Estimation of the current communication distance is calculated, and the default communication mechanism for the robot to be initialized is determined based on the infinite communication distance measurement data at the initial moment.

[0063] (2) When the device is located at the boundary of long-distance and short-distance signal communication distance, the controller sends a signal to switch the communication mode according to the signal stability.

[0064] (3) The device begins the authentication process by sending an authentication request frame. The authentication request frame is a message sent by the device to inform the new AP of its identity.

[0065] (4) The new AP responds to the authentication request by sending an authentication response frame to indicate whether the new AP accepts or rejects the device.

[0066] (5) Once the authentication process is successfully completed, the device can send a reassociation request frame to the new AP.

[0067] (6) Finally, the new AP sends a reassociation response frame containing information about whether to accept or reject this device.

[0068] For short-range communication, 433MHz wireless communication is used. The operating frequency of this data transmission module is 315MHz, and it uses a surface acoustic wave resonator (SAW) for frequency stabilization, which has the advantages of low communication delay and low cost. Using high-frequency RF technology, it consists of a single-IC RF front-end and an ATMEL AVR microcontroller. This miniature transceiver can transmit data signals at high speed and package, detect errors, and correct errors in wirelessly transmitted data. Due to the high reception sensitivity and good diffraction performance of 433MHz, we generally use 433MHz products to implement master-slave communication systems. This method has the advantages of relatively easy networking, low cost requirements, and a relatively complex operating environment, so the use of a 433MHz wireless module is appropriate.

[0069] When communicating over long distances outdoors, a combination of 3G / 4G and LoRa wireless communications ensures seamless communication. LoRa technology's advantages, such as wide coverage, low power consumption, and ease of deployment, have led to the proposal to apply it to remote robotic communications. LoRa is a low-power local area network wireless standard designed to address the conflict between power consumption and transmission distance, achieving a balance between low power consumption and long distances.

[0070] To enable communication terminals to support both long- and short-range communications, a rigorous and reliable automatic switching mechanism for long- and short-range communications is required. Leveraging the strengths of each communication mechanism, switching between these modes can be effectively controlled to ensure secure data communications. Handover refers to the process of switching the communication channel from one wireless channel to another while ensuring uninterrupted communication during mobile communications. This refers to the process of reassociating with a new access point and disconnecting from the original access point when a robot reaches the boundary between the coverage areas of two basic service sets. To cope with the ubiquitous wireless communication technology of today, and given the limited coverage of access points for 433M wireless communications, handover undoubtedly plays a crucial role.

[0071] Supporting both short-range and long-range communications simultaneously is actually contradictory. Short-range communications not only require communication at close range, but also specifically require that the effective coverage of the RF signal must not exceed the range specified for short-range communications to ensure secure communication. This obviously makes long-range communications impossible, creating a contradiction. However, short-range communications are possible in long-range communications, presenting no problem. Therefore, the core issue in supporting both short-range and long-range communications is enabling communication terminals to switch operating modes and control RF coverage.

[0072] The controller collects digital communication bandwidth measurement data from the wireless channel and determines the robot's communication mechanism for each cycle through computational analysis. It then sends a switching instruction to the controller to set up two transceivers in parallel that can independently perform communication tasks. The specific process for selecting and switching between 433M wireless communication and LoRa wireless communication is as follows:

[0073] 1) Estimate the current communication distance and determine the default communication mechanism for initializing the device based on the initial wireless communication distance measurement data. The wireless communication distance calculation formula can be expressed as:

[0074] Los=32.44+20lgD+20lgF(1)

[0075] In formula (1), Los, D, and F correspond to transmission loss, transmission distance, and communication frequency, respectively. When switching communication modes, the communication distance can be estimated based on the calculation results, and the appropriate communication mode can be selected.

[0076] 2) When the device is located at the boundary of the long-distance and short-distance signal communication distance, the controller sends the signal to switch the communication mode according to the signal stability. The calculation formula for extracting the characteristic statistics of the time series signal is shown in formulas (2)(3)(4)(5):

[0077]

[0078]

[0079] γ(t,s)=E[(X t -μ t )(X s -μ s )] (4)

[0080]

[0081] Where μ t 、 γ(t, s) and ρ(t, s) are the signal mean, variance, autocovariance, and autocorrelation coefficient, respectively. According to the above calculation results, if the following conditions are met, the time series is wide-stationary, and this indicator can be used as one of the indicators to measure the stability of wireless signal quality:

[0082] 1. For any t∈T, we have

[0083] 2. For any t∈T, there is EX t =μ, where μ is a constant

[0084] 3. For any t, s, k∈T, k+st∈T, we have γ(t, s)=γ(k, k+st)

[0085] When choosing between different communication methods, there is no need to switch frequently within the applicable range of each communication method. In principle, communication stability, communication quality, bit error rate, and packet loss rate are the primary considerations where the applicable distances of each communication method overlap. However, if there are special requirements such as energy consumption, the most suitable communication mode can be comprehensively considered.

[0086] AP discovery: Due to device mobility, the signal strength and signal-to-noise ratio (SNR) of the signal from the device's current associated AP decrease. When these values ​​drop below a certain threshold, the device loses connection with the current AP, triggering a handover. At this point, communication between the device and the current AP is likely to be lost. Therefore, to reduce handover latency, the device must identify a set of potential associated APs before disconnecting from the current AP.

[0087] Reauthentication between a device and a new AP: The reauthentication process between a device and a new AP involves both authentication and reassociation. This is the process of transferring the device's credentials from the previously associated AP to the new AP. The authentication process involves the AP either accepting or rejecting the device's identity.

[0088] Communication mode switching can generally be divided into hard switching and soft switching.

[0089] A hard handoff involves switching between base stations or sectors on different frequencies. During the handoff process, the mobile station must first disconnect from the original base station, tune to the new frequency, and then reconnect to the new base station within a specified timeframe. Therefore, the hard handoff process is: disconnect first, then handoff. During the handoff, a handoff command is sent on the original channel, temporarily suspending communication, and then tuning to the new channel frequency.

[0090] Both existing TACS and GSM systems use hard handoffs. When a handoff occurs, because the carrier frequencies of the original and new base stations differ, the mobile station must disconnect from the original base station before receiving signals from the new one. Once the mobile station's link with the original base station is severed, it often cannot immediately reestablish a link with the new one (GSM has a disconnection time of approximately 200ms, while TACS has a disconnection time of approximately 500ms). Therefore, hard handoffs can affect call quality to a certain extent. Furthermore, because hard handoffs involve a "disconnect first, then switch" approach, interference during the disconnection time or improper handoff parameter settings can lead to handoff failures and dropped calls. When the hard handoff area is narrow, a "ping-pong effect" of back-and-forth handoffs between the new and original base stations can occur, impacting traffic channel transmission.

[0091] Soft handoff is a switch between different base stations on the same frequency. During the handoff process, the mobile station maintains a communication link with both the original and new base stations. It does not disconnect from the original base station until it enters the new base station and measures the transmission quality of the new base station to meet the required specifications. Therefore, soft handoff is a "handoff first, disconnect later" process. During the handoff process, the mobile station does not lose contact with the original base station, truly achieving "seamless" handoff. Because soft handoff is a "handoff first, disconnect later" process, the mobile station only loses contact with the original base station after establishing a link with the new base station. Therefore, there is no interruption during the handoff process, and call quality is not affected. Because soft handoff is performed between base stations with the same frequency, at the junction of the two base station coverage areas, the mobile station communicates with multiple base stations simultaneously, which acts as a service channel diversity, thereby greatly reducing call drops caused by handoff. In addition, since both the mobile station and the base station use diversity reception technology in soft switching, they have low fading resistance. At the same time, through reverse power control, we can reduce the transmission power of the mobile station to a minimum, thereby reducing the interference of the mobile station to the system. Even if the mobile station entering the soft switching area cannot immediately obtain a link with the new base station, it can enter the switching waiting arrangement, thereby reducing the blocking rate of the system.

[0092] The present invention checks the instrument based on mobile Internet of Things technology, eliminating the trouble of meter reading and preventing problems such as missed reading and wrong reading. It uses the MQTT transmission protocol to store data in the cloud server database, and designs PC clients and mobile phone APPs to facilitate enterprises to retrieve and analyze data at any time.

[0093] The present invention adopts Internet of Things technology and has no restrictions on the use distance of the equipment. When employees of some instrument manufacturing companies are on business trips to maintain the company's instruments, they can directly upload the current status of the instruments to the server, making it convenient for the company to detect the current usage of products in the market and optimize the products.

[0094] The present invention can not only upload data to the server, but also control the device through the host computer. It can be deployed in the factory for a long time, so that the device can be turned on at any time on the mobile terminal to detect and monitor the instrument without manpower, greatly reducing labor costs and improving production efficiency.

[0095] At the same time, the present invention can comprehensively consider the currently required communication mode according to conditions such as communication distance, channel quality, energy consumption requirements, etc., and can ensure the reliability of communication to the greatest extent, reduce information loss and energy waste.

[0096] It will be understood that the present invention is described by way of some embodiments, and it will be appreciated by those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are intended to be protected by the present invention.

Claims

1. A monitoring method for a remote instrument monitoring device based on the Internet of Things, wherein the remote instrument monitoring device comprises three parts: a perception layer, a network layer, and an application layer. The perception layer comprises a controller, a sensor, an NB-Iot wireless transmission module, and an actuator. The controller and the sensor, and the controller and the NB-Iot wireless transmission module all use serial communication to achieve two-way data transmission. The network layer comprises an NB-Iot base station and a OneNet cloud platform. The NB-Iot base station modulates and demodulates the data transmitted by the perception layer, encapsulates it in a network data packet format, and forwards it to the OneNet cloud platform via LwM2M. In the cloud service A program for real-time message forwarding is deployed on the device, and the cloud server transfers the program to the database and the host computer; the OneNet cloud platform sends control instructions to the perception layer through the NB-Iot base station, thereby controlling the actuators of the perception layer. The application layer includes multiple current and voltage display channels after the power is turned on for factory instruments, which are used to view the real-time data of different devices and control the devices; the data of the specified time period is retrieved from the OneNet cloud platform database, and tables of different formats are generated and saved locally; the controller controls the NB-Iot wireless transmission module to communicate with the cloud platform through the serial port with AT instructions, and transmits data to the cloud platform, which is characterized in that The monitoring method includes a communication switching method, and the communication switching method includes the following steps: Step 1: Estimate the current communication distance and determine the default communication mechanism for device initialization based on the initial unlimited communication distance measurement data. Step 2: When the device is located at the boundary of the long-distance and short-distance signal communication distance, the controller sends a signal to switch the communication mode according to the signal stability; Step 3: The device begins the authentication process by sending an authentication request frame. The authentication request frame is a message sent by the device to inform the new AP of its identity. Step 4: The new AP responds to the authentication request by sending an authentication response frame to indicate whether the new AP accepts or rejects the device. Step 5: Once the authentication process is successfully completed, the device sends a reassociation request frame to the new AP. Step 6: Finally, the new AP sends a reassociation response frame containing information about accepting or rejecting the device. The controller collects wireless channel digital communication bandwidth measurement data and determines the robot's communication mechanism for each cycle through computational analysis. It then sends a switching instruction to the controller, setting up two transceivers that independently perform communication tasks in parallel. The specific process for selecting and switching between 433M wireless communication and LoRa wireless communication is as follows: Step 1: Estimate and calculate the current communication distance. Based on the initial unlimited communication distance measurement data, determine the default communication mechanism for device initialization at this time. The wireless communication distance calculation formula is expressed as formula (1): Los = 32.44 + 20lgD + 20lgF (1) In formula (1), Los, D, and F correspond to transmission loss, transmission distance, and communication frequency, respectively. When switching the communication mode, the communication distance is estimated based on the calculation results and the communication mode is selected. Step 2: When the device is located at the boundary of the long-distance and short-distance signal communication distance, the communication mode of the controller sending the signal is switched according to the signal stability. The calculation formula for extracting the time series signal feature statistics is shown in formulas (2)(3)(4)(5): γ(t,s)=E[(X t -m t )(X s -m s )] (4) Where μ t 、 γ(t,s) and ρ(t,s) are the signal mean, variance, autocovariance, and autocorrelation coefficient, respectively. According to the above calculation results, if the following conditions are met, the time series is wide-stationary. The characteristic statistics of the time series signal are used as one of the indicators to measure the stationarity of wireless signal quality:

1. For any t∈T, there is 2. For any t∈T, there is EX t =μ, where μ is a constant; 3. For any t, s, k∈T, k+st∈T, γ(t, s) = γ(k, k+st); Before disconnecting from the current AP, the device finds a set of possible associated APs in advance; the communication mode switching method is soft switching, which is switching between different base stations with the same frequency. During the switching process, the mobile station maintains communication links with both the original base station and the new base station until it enters the new base station and measures that the transmission quality of the new base station meets the index requirements, at which time it disconnects from the original base station.

2. The monitoring method according to claim 1, characterized in that: It includes a power supply module, which is responsible for powering the factory equipment and the monitoring device. The controller of the perception layer includes an STM32 main control, which is responsible for receiving the collected data of the terminal and sending the data to the cloud platform through the Internet of Things module after programming according to the communication protocol. The NB-Iot wireless transmission module is responsible for wireless long-distance communication between the terminal and the cloud server. The sensor includes a voltage acquisition circuit, a current acquisition circuit and a temperature acquisition circuit. The voltage acquisition circuit is responsible for collecting the instrument voltage value, the current acquisition circuit is responsible for collecting the instrument current value, and the temperature acquisition circuit is responsible for collecting the current ambient temperature value. The OneNet cloud platform receives sensor detection results and data through the NB-Iot wireless transmission module for unified management, and can detect whether the data is abnormal by manually setting parameter thresholds. When the corresponding value exceeds the set threshold, a warning message will be triggered and the monitoring administrator can be notified via SMS or email.

3. The monitoring method according to claim 2, characterized in that: The temperature acquisition circuit model is PT100, and the controller model is STM32F103VET6.

4. The monitoring method according to claim 2, characterized in that: The application layer includes an LED screen, which is used to display data collected by the temperature acquisition circuit PT100 and the voltage and current acquisition circuit.

5. The monitoring method according to claim 2, characterized in that: The application layer includes a client, which is used to view data in real time, retrieve past data, and control factory equipment.

6. The monitoring method according to claim 1, characterized in that: 433M wireless communication is used for short distance, and 3 / 4G and LoRa wireless communication are used for long distance.

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