Equipment operation life sensor

Abstract

The invention relates to an equipment operation life sensor, which comprises a product structure and a hardware circuit with an embedded software program, a shell and a circuit board assembly are rigidly connected by a sensor mounting bracket through bolts, and effective conduction of vibration signals is realized; an MEMS accelerometer sensor in a hardware circuit collects analog signals and then enters a signal conditioning circuit, an MCU main control chip modifies the collection mode of hardware according to different function configurations, controls the overall working dormancy state of the sensor and completes core calculation and storage on digital signals received by a sampling circuit, and a wireless communication module receives a data sending request and then sends the data to the signal conditioning circuit. And the power management module supplies power to the sensor acquisition chip, the MCU main control chip and the wireless communication module, and dynamically adjusts the working state of the modules according to a power management strategy, so that the power consumption of equipment is reduced, and the requirements of low power consumption, high precision and function of the service life sensor are met.

Description

Technical Field

[0001] The invention relates to a mechanical equipment state monitoring device, in particular to an equipment operation life sensor. Background Art

[0002] With the long-term use of electromechanical equipment and the influence of environmental factors, the reliability of the equipment will gradually decrease. Therefore, it is particularly important to count the operating life of electromechanical equipment, which not only helps the maintenance team monitor the status of the equipment, but also predicts the time point for maintenance or replacement, thereby avoiding sudden equipment failure. The traditional method of counting the operating time of equipment is manual detection. This method is simple, fast, and easy to execute, but it has the disadvantages of low reliability, non-real-time, inaccurate, and consumes a lot of manpower. With the development of science and technology, the electric control box detection current is gradually used in engineering applications to statistically monitor the operating time of electromechanical equipment. This method can realize the automatic judgment of the start and stop of electromechanical equipment and the automatic statistics of the operating time, but this method is a wired connection, which requires large-scale wiring and has strict requirements on the installation environment. In addition, the electronic ledgers of the start and stop of each device cannot be aggregated and transmitted to a server, and there is an information island problem.

[0003] In summary, the existing methods for counting the operating life of mechanical equipment, including manual counting and current detection, still have the following key problems:

[0004] 1. Manual statistics have low reliability, inaccuracy and low efficiency. In the traditional method of manually counting the running time of mechanical equipment, it is necessary to manually record the start and stop time of the equipment to form a handwritten ledger. Sometimes the startup time of the equipment is short, and manual statistics will miss records, and the handwritten ledger is easy to lose; because it is impossible to form an electronic ledger, manual calculation is still required when calculating the running time of a certain time interval, which is inefficient and low in precision. Therefore, it is necessary to realize automatic judgment of start and stop in the life sensor and form an electronic ledger record to solve the problems of manual statistics.

[0005] 2. There are difficulties in the layout of the electric control box to detect the current, and there is an information island problem. The method of using the electric control box to detect the current to determine the start and stop of the equipment and form an electronic ledger has high accuracy and timely response. However, this method often reserves the installation space and layout plan in advance before the mechanical equipment is installed, and it is impossible to reinstall the equipment that has been put into use; and the electronic ledger formed in this way often cannot be centrally transmitted to a server, and cannot be analyzed together according to a unified protocol and format, and there is an information island problem. Therefore, a suitable method needs to be adopted in the life sensor to achieve simple sensor layout and unified analysis of the electronic ledgers of each device to solve the problem of detecting current to determine the start and stop.

[0006] 3. Excessive power consumption. The life sensor collects vibration data from electromechanical equipment, and the built-in MCU processes and analyzes the data through algorithms to determine the start and stop status of the electromechanical equipment, and transmits the data to the host computer through wireless transmission. However, frequent data collection at a high sampling rate and Bluetooth connection will greatly increase the power consumption of the sensor, and the original limited capacity battery will significantly shorten the working time of the system. Therefore, it is still necessary to choose a suitable method to reduce the power consumption of the life sensor.

[0007] 4. Algorithm logic. The life sensor determines the start and stop status of the equipment through vibration data. In actual applications, the environment in which the equipment is located may have various interferences. The logic and indicators of the algorithm must be able to filter out interference conditions to improve the judgment accuracy.

[0008] 5. Ensure the accuracy of the internal clock. When the life sensor counts the running time of the equipment, the accuracy of its internal clock is closely related to the accuracy of the start and stop time ledger, so reasonable measures should be taken to ensure the accuracy of the internal clock. Summary of the invention

[0009] The present invention proposes an equipment operation life sensor for statistics of electromechanical equipment operation time. The sensor is magnetically mounted on the electromechanical equipment, and the vibration of the electromechanical equipment is sensed by a built-in MEMS acceleration chip. The vibration data is then processed by ADC analog-to-digital conversion and an algorithm in an MCU to form an electronic start and stop log of the electromechanical equipment. Finally, the log is wirelessly transmitted to a host computer through a Bluetooth module. The sensor is used to solve the key problem of automatic judgment of the start and stop of the electromechanical equipment and transmission and display in an environment with difficult wiring, narrow space, and mixed interference, thereby realizing simple layout of the life sensor, low-power operation, and high-precision judgment of the start and stop status.

[0010] To achieve the above purpose, the technical solution of the present invention is: a device operation life sensor, including a product structure, a sensor, and a hardware circuit with an embedded software program. The product structure includes a shell component, a circuit board component, an interface component, and a battery component. The circuit board component is fixedly connected to the lower shell by fasteners. The sensor mounting bracket forms a rigid connection between the shell and the circuit board component by bolts to achieve effective conduction of vibration signals; the hardware circuit includes a MEMS accelerometer, an MCU main control chip, a power management module, a wireless communication module, an RTC clock module, and a power meter module. After the MEMS accelerometer sensor collects analog signals, it enters the signal conditioning circuit, and the collected analog signals are converted by the AD analog-to-digital conversion module. The MCU main control chip modifies the hardware acquisition mode according to different functional configurations, controls the overall working dormant state of the sensor, completes the core calculation and storage of the digital signal received by the sampling circuit, and after the wireless communication module receives the request to send data, it sends the data to the companion test tablet APP. The power management module supplies power to the sensor acquisition chip, the MCU main control chip, and the wireless communication module, and dynamically adjusts the module working state according to the power management strategy to reduce the power consumption of the equipment and meet the low power consumption, high precision and functional requirements of the life sensor.

[0011] Furthermore, the product structure adopts an easy-to-open battery compartment, the upper shell and the battery compartment are connected by threads, and the outer shell is opened by rotating the upper shell to replace the battery. The sensor is installed using a magnetic base to avoid drilling holes in the device.

[0012] Furthermore, an embedded software program is used to dynamically configure the sensor according to the configuration parameters set by the user, such as determining the start-stop time interval, axis, and characteristic parameter threshold; hardware driver implementation, implementing the peripheral driver of the MCU around the MCU, including RTC, ADC, EEPROM, Bluetooth, and power meter driver; wake-up mechanism, the system is in a low-power state waiting for timed wake-up or Bluetooth wake-up, thereby reducing power consumption for long-term operation, thereby enabling the life sensor to adopt multiple working modes to complete the task.

[0013] Furthermore, in order to ensure that the sensor works in a low-power state for a long time to ensure the long-term operation of the device, different collection and calculation modes and communication modes are entered according to different task requirements. In this mode, vibration signals are collected, vibration characteristics are calculated, the operating status of the device is judged, and the total operating time of the device is updated. When the user connects to Bluetooth, the sensor should enter the communication mode, upload the acquired equipment operating time, power on and off records and other information to the user, and complete tasks such as time correction and user configuration modification. After completing the corresponding tasks in each mode, the sensor should return to the low-power state.

[0014] Furthermore, the embedded software program adds a threshold value acquisition mode for the life sensor. When a life sensor is installed on a device for the first time, the threshold value is set first, and then the start and stop status of the device at the current moment is determined regularly.

[0015] Furthermore, the life sensor is divided into two modes for judging the start and stop of the equipment: a threshold setting mode and a normal working mode; the threshold configuration mode sets personalized thresholds for different electromechanical equipment; three sets of data are collected in the normal working mode, and the equipment is judged to be in the start-up state only when all three sets of data are greater than the set thresholds.

[0016] Furthermore, embedded software programs are used on mobile terminals to customize the monitored equipment and parameters. In the host computer, electromechanical equipment is classified according to the cabin and equipment name, and the electronic ledgers uploaded by the sensors are arranged and displayed in a unified format. After the sensor is installed, the user performs basic configuration of the interface and sets the start-stop vibration threshold of the acquisition equipment. After the life sensor has run for a period of time, the sensor data is obtained and stored through wireless transmission on the APP. The start-stop time ledger, usage time, vibration status and other information of the installed equipment can be directly viewed on the interface, and the platform software can be connected to realize the upload of time data to provide data support for further maintenance tasks.

[0017] The beneficial effects of the present invention are:

[0018] The present invention proposes a life sensor that uses wireless Bluetooth transmission and signal processing to determine the start and stop of equipment and to count the running time. The specific beneficial effects are:

[0019] 1. Automatically determine the start and stop of the equipment and form an electronic ledger. The life sensor automatically determines the start and stop status of the equipment by sensing the vibration data of the equipment and the built-in algorithm, and transmits the electronic ledger to the host computer according to the Bluetooth communication protocol, overcoming the problems of low reliability, low accuracy and low efficiency of traditional manual statistics.

[0020] 2. Wireless transmission, unified upload, adaptability to complex environments: Life sensors wirelessly transmit time records and other data to a tablet host computer via Bluetooth, which can avoid wiring problems in narrow spaces, simplify layout conditions, and allow sensors to adapt to the environments of most electromechanical equipment. Sensors installed on different electromechanical equipment can transmit electronic records to the host computer in a unified format, and the electronic records are displayed on the host computer in a classified manner according to the compartment and name of the equipment, thereby solving the layout difficulties and information island problems of traditional current detection to determine start and stop.

[0021] 3. Low power consumption of the sensor: The life sensor is designed with embedded software to switch between three working modes: low power sleep mode, communication mode, and computing mode. The sensor is in sleep mode most of the time and only experiences a short period of high power consumption when it wakes up regularly to collect and transmit data. Therefore, the sensor can work for a long time and the battery replacement frequency is low.

[0022] 4. Improve the accuracy of judging the start and stop of equipment: The life sensor selects time-frequency indicators, square root amplitude and total vibration value; adds a threshold configuration mode, and uses three sets of data to reduce the misjudgment rate, which can eliminate interference conditions and improve the accuracy of judging the start and stop of equipment.

[0023] 5. Improve the accuracy of time records: The life sensor ensures that the error between the clock in the sensor and the standard clock is controlled within a certain range by regularly sending calibration data packets and the clock power-off retention function, thereby improving the accuracy of the time record. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structural composition of the life sensor of the present invention;

[0025] Figure 2 is a schematic diagram of embedded software for a life sensor of the present invention;

[0026] Figure 3 This is a working diagram of the low power consumption mode of the life sensor of the present invention. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0028] An embodiment of the present invention provides a device operation life sensor, including:

[0029] (1) Product structure: The life sensor is specifically designed for special scenarios. It is designed to be as compact as possible while meeting the collection and heat dissipation requirements to reduce the size of the sensor. The overall structure includes the shell component, circuit board component, interface component, and battery component, which achieves the IP44 protection level. The product can work safely in harsh environments. The structural design requires that on the basis of functional realization, multiple constraints such as environmental adaptability, heat dissipation, electromagnetic protection, and wireless communication efficiency be comprehensively considered to ensure that the product is safe and durable, stable in operation, and has excellent performance. The structural composition of the life sensor is as follows: Figure 1 shown.

[0030] (2) Hardware design: The hardware circuit mainly includes MEMS accelerometer, MCU main control chip, power management module, wireless communication module, RTC clock module and fuel gauge module. After the MEMS accelerometer sensor collects analog signals, it enters the signal conditioning circuit and converts the collected analog signals through the AD analog-to-digital conversion module. The MCU main control chip modifies the hardware acquisition method according to different functional configurations, controls the overall working sleep state of the sensor, and completes the core calculation and storage of the digital signal received by the sampling circuit. After receiving the request to send data, the wireless communication module sends the data to the companion tablet APP. During the operation of the entire device, the power module supplies power to the sensor acquisition chip, MCU main control chip, and wireless communication module, and dynamically adjusts the module working state according to the power management strategy to reduce the power consumption of the equipment and meet the low power consumption, high precision and functional requirements of the life sensor.

[0031] (3) Embedded software design: The embedded software mainly completes three tasks: dynamically configure the sensor according to the configuration parameters set by the user, such as judging the start-stop time interval, axis, and characteristic parameter threshold; hardware driver implementation, implement the peripheral driver of the MCU around the MCU, including RTC, ADC, EEPROM, Bluetooth, and power meter driver; wake-up mechanism, the system is in a low-power state waiting for timed wake-up or Bluetooth wake-up to reduce power consumption for long-term operation. Therefore, multiple working modes of the life sensor can be designed to complete the task. Specifically, the sensor should work in a low-power state for a long time to ensure the long-term operation of the equipment. According to different task requirements, it enters different acquisition and calculation modes and communication modes. In this mode, vibration signals are collected, vibration characteristics are calculated, the operating status of the equipment is judged, and the total operating time of the equipment is updated. When the user connects to Bluetooth, the sensor should enter the communication mode, upload the acquired equipment operating time, power on and off records and other information to the user, and complete tasks such as time correction and user configuration modification. After completing the corresponding tasks of each mode, the sensor should return to a low-power state. The embedded software flow box is as follows Figure 2 shown.

[0032] (4) Algorithm design

[0033] The vibration levels of different devices when starting and stopping vary greatly, and it is impossible to find a threshold value that applies to the characteristic values ​​of all devices. In response to this situation, the life sensor has added a threshold acquisition mode. When a life sensor is installed on a device for the first time, the threshold is set first, and then the start and stop status of the device at the current moment is determined regularly. The life sensor determines the start and stop of the device in two main steps: threshold setting mode and normal working mode. The threshold configuration mode can set personalized thresholds for different electromechanical equipment separately; 3 sets of data are collected in the normal working mode, and the device is judged to be in the start state only when all three sets of data are greater than the set threshold.

[0034] Regarding the selection of characteristic value indicators, one indicator is selected from each of the time domain and the frequency domain. The total vibration value is selected in the frequency domain because the total vibration value can reflect the vibration energy within the selected frequency range. The vibration energy of electromechanical equipment is significantly different when it is started and stopped. The square root amplitude is selected in the time domain because the square root amplitude can eliminate the misjudgment of equipment startup under interference conditions such as knocking. Figure 3 .

[0035] (5) Application software design

[0036] Develop a mobile software that can be used to customize the monitored equipment and parameters. In the host computer, electromechanical equipment is classified according to the cabin and equipment name, and the electronic ledger uploaded by the sensor is arranged and displayed in a unified format. After the sensor is installed, the user can perform basic configuration of the interface and set the start-stop vibration threshold of the acquisition equipment. After the life sensor has been running for a period of time, the sensor data and storage data can be obtained through wireless transmission on the APP. The start-stop time ledger, usage time, vibration status and other information of the installed equipment can be directly viewed on the interface. It can also be connected to the platform software to upload time data to provide data support for further maintenance tasks.

[0037] Specific embodiment: A device operation life sensor of the present invention includes:

[0038] 1) In terms of structural design, the battery compartment is designed to be easy to open. The upper shell and the battery compartment are connected by threads. The upper shell can be opened to replace the battery by rotating it. The sensor is installed on a magnetic base to avoid drilling holes on the device. The internal structure circuit board and the lower shell are fixed with four screws. In addition, in terms of vibration transmission design, the sensor mounting bracket forms a rigid connection between the shell and the circuit board assembly through four bolts with a diameter of 2mm. Effective transmission of vibration signals is achieved.

[0039] 2) In terms of the specific implementation of hardware design, it mainly includes accelerometer, MCU main control chip, power management module, etc. MEMS accelerometer provides a voltage output signal after signal conditioning, which is proportional to acceleration, does not require temperature compensation circuit, and does not have quantization error; MCU normally works in standby mode, which is the lowest power consumption mode among the three low-power modes of MCU. In standby mode, MCU turns off all clocks, turns off the core 1.8V power supply, and register and RAM data cannot be retained (except for the power control / status register (PWR_CSR) and backup register, all other data are lost); it can be awakened by the rising edge of the wake-up pin (PA0), RTC alarm interrupt, or reset; wake-up is equivalent to reset, and execution starts from the reset address; in terms of power management module, it is converted into 3.3V digital and 3V analog power supply through DC-DC and LDO power management chips, which provide power supply to digital devices and analog devices respectively, to avoid the pulse interference voltage on the digital circuit affecting the analog signal in the analog circuit, and adding power supply filtering and overvoltage protection design can reduce power supply noise interference and prevent overvoltage and overcurrent from damaging the circuit.

[0040] 3) Specific implementation and calculation of low-power design mode. When the sensor is turned on for the first time, it will initialize the system clock, configure Bluetooth low-power broadcast, initialize RTC, configure Bluetooth wake-up pins, and initialize the battery meter. Then the software will read the power and determine the power status to control the indicator light change, and finally enter the low-power mode. The two working modes after waking up from the low-power mode are computing mode and communication mode. The workflow of the low-power mode is as follows: Figure 3 As shown. It is determined that the current of the sensor in sleep state is 400μA, and the current during data collection and transmission is 43mA. The data collection time interval that can be set in the sensor configuration is 5min. The sensor is woken up by the timer every 5min, and vibration data is collected three times in succession, each time for 0.5s, which is equivalent to continuous collection for 1.5s. The power consumption during this period is 0.4*1 / 12+43*1.5 / 3600=0.051mAh. If the battery capacity is 3000mAh, the usable time is: 3000 / 0.051*301.5=17648780.487s=204.268 days.

[0041] 4) The specific implementation of the algorithm design is divided into threshold configuration mode and normal working mode. In the threshold configuration mode, the life sensor will continuously collect 10 sets of data when the device is turned on, and 10 sets of data when the device is turned off, with 1024 points in each set of data. In the upper computer interface, the power-on and power-off curves of the square root amplitude and the power-on and power-off curves of the total vibration value are formed. According to the difference between the two curves of power on and off, the user sets a judgment threshold for the two characteristic values ​​respectively, so as to realize the personalized threshold setting for different devices; in the normal working mode, the acceleration data of the current device is collected regularly, the characteristic value is calculated, and compared with the threshold set in the previous step to determine the start and stop status of the device at the current moment. Collect data three times in succession and judge. When the three judgment results are all power on, the device is judged to be powered on to prevent misjudgment caused by impact and other situations.

[0042] 5) The specific implementation of improving the accuracy of the time record is as follows: the clock inside the sensor is provided by the RTC. Under normal conditions, the RTC is powered by the No. 5 battery in the battery compartment. However, considering that the battery may be detached from the battery compartment when the sensor is replaced or impacted, in order to ensure that the RTC continues to run, a button battery is added to the circuit board to provide backup power supply to the BAT area of ​​the MCU; in addition, the crystal oscillator of the life sensor will have accumulated errors over time. In order to control this error, the host computer will send a time calibration data packet when sending a request data instruction to the sensor to ensure the accuracy of the time record.

Claims

1. A device operation life sensor, characterized in that: It includes product structure, sensor, and hardware circuit with embedded software program. The product structure includes shell component, circuit board component, interface component, and battery component. The circuit board component is fixedly connected to the lower shell by fasteners. The sensor mounting bracket forms a rigid connection between the shell and the circuit board component by bolts to realize the effective transmission of vibration signals. The hardware circuit includes MEMS accelerometer, MCU main control chip, power management module, wireless communication module, RTC clock module and power meter module. The MEMS accelerometer sensor collects analog signals and enters the signal conditioning circuit. The collected analog signals are converted by the AD analog-to-digital conversion module. The MCU main control chip modifies the hardware collection method according to different functional configurations, controls the overall working sleep state of the sensor, completes the core calculation and storage of the digital signal received by the sampling circuit, and sends the data to the companion tablet APP after receiving the data sending request. The power management module supplies power to the sensor acquisition chip, MCU main control chip, and wireless communication module, and dynamically adjusts the module working state according to the power management strategy to reduce the power consumption of the equipment and meet the low power consumption, high precision and functional requirements of the life sensor.

2. The equipment operation life sensor according to claim 1, characterized in that: The product structure adopts an easy-to-open battery compartment. The upper shell and the battery compartment are connected by threads. The battery can be replaced by rotating the upper shell to open the outer shell. The sensor is installed with a magnetic base to avoid drilling holes in the device.

3. The equipment operation life sensor according to claim 1, characterized in that: Embedded software program, used to dynamically configure the sensor according to the configuration parameters set by the user, such as judging the start-stop time interval, axis, and characteristic parameter threshold; hardware driver implementation, implementing the peripheral driver of the MCU around the MCU, including RTC, ADC, EEPROM, Bluetooth, and power meter driver; wake-up mechanism, the system is in a low-power state waiting for timed wake-up or Bluetooth wake-up, reducing power consumption for long-term operation, thereby enabling the life sensor to adopt multiple working modes to complete the task.

4. The equipment operation life sensor according to claim 3, characterized in that: To ensure that the sensor works in a low-power state for a long time to ensure the long-term operation of the device, different acquisition and calculation modes and communication modes are entered according to different task requirements. In this mode, vibration signals are collected, vibration characteristics are calculated, the operating status of the device is judged, and the total operating time of the device is updated; When the user makes a Bluetooth connection, the sensor should enter the communication mode and upload the acquired information such as the device operating time and power on / off records to the user. At the same time, it should complete tasks such as time correction and user configuration modification. After completing the corresponding tasks in each mode, the sensor should return to a low power consumption state.

5. The equipment operation life sensor according to claim 1, characterized in that: The embedded software program adds a threshold acquisition mode for the life sensor. When a life sensor is installed on a device for the first time, the threshold is set first, and then the start and stop status of the device at the current moment is determined regularly.

6. The equipment operation life sensor according to claim 5, characterized in that: The life sensor determines the start and stop of the equipment in two modes: threshold setting mode and normal working mode. The threshold configuration mode sets personalized thresholds for different electromechanical equipment. Three sets of data are collected in the normal working mode. When all three sets of data are greater than the set threshold, the equipment is judged to be in the start state.

7. The equipment operation life sensor according to claim 1, characterized in that: Embedded software program, used on mobile terminals, customizes the monitored equipment and parameters. In the host computer, electromechanical equipment is classified according to the cabin and equipment name, and the electronic ledger uploaded by the sensor is arranged and displayed in a unified format. After the sensor is installed, the user performs basic configuration of the interface and sets the start-stop vibration threshold of the acquisition equipment. After the life sensor has been running for a period of time, the sensor data is obtained and stored through wireless transmission on the APP. The start-stop time ledger, usage time, vibration status and other information of the installed equipment can be directly viewed on the interface, and the platform software can be connected to realize the upload of time data to provide data support for further maintenance tasks.

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