Thermal shock detection circuit and method of predictive maintenance of equipment

Abstract

The present application belongs to the technical field of airborne computer, and particularly relates to a thermal vibration detection circuit and a predictive maintenance method for equipment. The thermal vibration detection circuit comprises a vibration measurement module, a temperature measurement module, a microcontroller and a memory. The predictive maintenance method for equipment is as follows: a predictive maintenance model of the equipment is established, the temperature data, the vibration data and the cumulative running time of the equipment are recorded through testing, the predictive maintenance information of each part of the equipment is calculated, including the predictive service life of the thermal vibration sensitive element of the equipment, the BIT self-checking reminder of on-board maintenance, the fastener point inspection reminder and the artificial maintenance reminder information. The present application monitors the thermal vibration environment information of the airborne computer equipment in real time, and solves the problem of inaccurate stress fatigue damage estimation in the traditional method. The stress fatigue damage condition of the equipment is calculated by establishing the predictive maintenance model.

Description

Technical Field

[0001] This invention belongs to the field of airborne computer technology, specifically relating to a thermal vibration detection circuit and a predictive maintenance method for equipment. Background Technology

[0002] Airborne computers are characterized by high complexity and high chip integration. Due to the unique airborne environment, aviation electromechanical management computers are subjected to harsh conditions of high vibration and shock, and high temperature cycling for extended periods. As aircraft age, persistent temperature shocks and mechanical vibrations will cause microscopic damage to the highly integrated circuits within the airborne computer, a phenomenon known as stress fatigue. When the stress fatigue of materials accumulates and exceeds its limit, damage will occur. At this point, the highly integrated circuits may experience explicit or implicit localized failures due to material failure, posing a threat to flight safety.

[0003] Currently, fatigue damage prediction for airborne computers is mainly achieved through calculations, simulations, and experiments during the design phase. However, these methods struggle to predict the damage to materials caused by unpredictable "large vibrations" and "intense temperature shocks" during actual flight. Therefore, the fatigue damage calculation results obtained through traditional methods during the design phase often contain certain deviations. Summary of the Invention

[0004] In view of this, this invention proposes a thermal vibration detection circuit and a predictive maintenance method for equipment. This method monitors the thermal vibration environment information of airborne computer equipment in real time, solving the problem of inaccurate stress fatigue damage prediction in traditional methods. By establishing a predictive maintenance model, the stress fatigue damage status of the equipment is calculated. When the equipment's stress fatigue status exceeds a preset stress fatigue threshold, the avionics system is notified via the airborne network bus, informing aircraft maintenance personnel to conduct further inspection and maintenance, thus ensuring flight safety.

[0005] To achieve the above-mentioned technical objectives, the specific technical solution adopted by the present invention is as follows:

[0006] A thermal vibration detection circuit includes: a vibration measurement module, a temperature measurement module, a microcontroller, and a memory;

[0007] The vibration measurement module is used to measure the amount of vibration experienced by the device under test; it consists of five accelerometers respectively located at the four corners and the center of the printed circuit board of the device under test.

[0008] The temperature measurement module is used to measure the temperature of the device under test, and includes at least two thermistors and driving and acquisition circuits; the thermistors are distributed in the heat-prone areas and the room temperature area of ​​the printed circuit board.

[0009] The memory is used to store flight time, equipment vibration and temperature data, material thermal fatigue stress data, and predictive maintenance model data;

[0010] The microcontroller is used to collect real-time acceleration and real-time temperature measured by the vibration measurement module and the temperature measurement module, and calculates the current thermal fatigue stress information by combining the data stored in the memory with the data through a mathematical model.

[0011] Furthermore, after the microcontroller collects the sampled values ​​of each accelerometer, it performs low-pass filtering to remove measurement singularities caused by noise, sorts the five filtered sampled values ​​from largest to smallest, and takes the second sampled result as the measured value.

[0012] Furthermore, this invention also proposes a predictive maintenance method for equipment based on the above-mentioned thermal vibration detection circuit, comprising the following steps:

[0013] Establish a predictive maintenance model to calculate the thermal vibration fatigue stress information of various parts of the tested equipment using real-time temperature data, historical temperature data, real-time vibration data, historical vibration data, and cumulative operating time.

[0014] Predictive maintenance information is obtained based on thermal shock fatigue stress information;

[0015] The device under test is maintained based on the predictive maintenance information;

[0016] The predictive maintenance information includes predicted lifespan of equipment thermal vibration sensitive components, on-board maintenance BIT self-test reminders, fastener inspection reminders, and manual maintenance reminders.

[0017] Furthermore, the thermal shock fatigue stress information includes temperature fatigue damage. and vibration fatigue damage ;

[0018] The temperature fatigue damage Calculated by the following formula,

[0019]

[0020] in, for Temperature reading difference over a period of time The sampling time interval, That is, the rate of temperature change within the sampling time interval. The critical value for thermal fatigue damage is defined as the rate of temperature change being less than the critical value for thermal fatigue damage. The temperature fatigue damage is 0, meaning that the temperature change rate is considered to be no order of magnitude that will cause temperature fatigue damage to the equipment.

[0021] Vibration fatigue damage Calculated by the following formula:

[0022]

[0023] in, The real-time acceleration value of the device obtained by the accelerometer. For the quality of chips in equipment that are sensitive to thermal shock; This is the critical value for vibration fatigue damage; when the real-time acceleration is less than the critical value for vibration fatigue damage... The vibration fatigue stress is 0, which means that the vibration level will not cause vibration fatigue damage to the equipment.

[0024] Thermal fatigue stress information is characterized by the summation of vibration fatigue damage and temperature fatigue damage. ;

[0025] in: S This is thermal fatigue stress information.

[0026] Furthermore, the predicted lifetime of the device under test is characterized as follows: ,in, To predict lifespan, For design life, The conversion factor is determined by the stress-life characteristics.

[0027] Furthermore, the on-board maintenance BIT self-check reminder, fastener inspection reminder, and manual maintenance reminder are compared and judged based on the on-board maintenance BIT self-check reminder threshold, fastener inspection reminder threshold, and manual maintenance reminder threshold, respectively. When the equipment accumulates fatigue damage... , as well as When the thresholds for onboard maintenance BIT self-test reminder, fastener inspection reminder, and / or manual maintenance reminder are reached, the microcontroller sends an inspection and maintenance reminder message to the avionics system via the airborne network. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the composition structure of the thermal vibration detection circuit in a specific embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of the layout of the accelerometer and thermistor in a specific embodiment of the present invention;

[0031] Figure 3 This is a schematic block diagram of the predictive maintenance method in a specific embodiment of the present invention. Detailed Implementation

[0032] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0033] The following specific examples illustrate the implementation of this disclosure. Those skilled in the art can easily understand other advantages and effects of this disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. This disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this disclosure. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0034] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this disclosure, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using other structures and / or functionalities besides one or more of the aspects set forth herein.

[0035] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this disclosure. The illustrations only show the components related to this disclosure and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0036] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0037] In one embodiment of the present invention, a thermal vibration detection circuit is provided, comprising: a vibration measurement module, a temperature measurement module, a microcontroller, and a memory;

[0038] The vibration measurement module is used to measure the amount of vibration experienced by the device under test; it consists of five accelerometers respectively located at the four corners and the center of the printed circuit board of the device under test.

[0039] The temperature measurement module is used to measure the temperature of the device under test, and includes at least two thermistors and driving and acquisition circuits; the thermistors are distributed in the heat-prone areas and the room temperature area of ​​the printed circuit board.

[0040] The memory is used to store flight time, equipment vibration and temperature data, material thermal fatigue stress data, and predictive maintenance model data;

[0041] The microcontroller is used to collect real-time acceleration and real-time temperature measured by the vibration measurement module and the temperature measurement module, and calculates the current thermal fatigue stress information by combining the data stored in the memory with the data through a mathematical model.

[0042] In this embodiment, after the microcontroller collects the sampled values ​​of each accelerometer, it performs low-pass filtering to remove measurement singularities caused by noise, sorts the five filtered sampled values ​​from largest to smallest, and takes the second sampled result as the measured value.

[0043] Based on the same inventive concept, in one embodiment, the present invention also proposes a predictive maintenance method for equipment based on the above-described thermal vibration detection circuit, comprising the following steps:

[0044] Establish a predictive maintenance model to calculate the thermal vibration fatigue stress information of various parts of the tested equipment using real-time temperature data, historical temperature data, real-time vibration data, historical vibration data, and cumulative operating time.

[0045] Predictive maintenance information is obtained based on thermal shock fatigue stress information;

[0046] The device under test is maintained based on the predictive maintenance information;

[0047] The predictive maintenance information includes predicted lifespan of equipment thermal vibration sensitive components, on-board maintenance BIT self-test reminders, fastener inspection reminders, and manual maintenance reminders.

[0048] In this embodiment, the thermal fatigue stress information includes temperature fatigue damage. and vibration fatigue damage ;

[0049] The temperature fatigue damage Calculated by the following formula,

[0050]

[0051] in, for Temperature reading difference over a period of time The sampling time interval, That is, the rate of temperature change within the sampling time interval. The critical value for thermal fatigue damage is defined as the rate of temperature change being less than the critical value for thermal fatigue damage. The temperature fatigue damage is 0, meaning that the temperature change rate is considered to be no order of magnitude that will cause temperature fatigue damage to the equipment.

[0052] Vibration fatigue damage Calculated by the following formula:

[0053]

[0054] in, The real-time acceleration value of the device obtained by the accelerometer. For the quality of chips in equipment that are sensitive to thermal shock; This is the critical value for vibration fatigue damage; when the real-time acceleration is less than the critical value for vibration fatigue damage... The vibration fatigue stress is 0, which means that the vibration level will not cause vibration fatigue damage to the equipment.

[0055] Thermal fatigue stress information is characterized by the summation of vibration fatigue damage and temperature fatigue damage. ;

[0056] in: S This is thermal fatigue stress information.

[0057] In this embodiment, the predicted lifetime of the device under test is characterized as follows: ,in, To predict lifespan, For design life, The conversion factor is determined by the stress-life characteristics.

[0058] In this embodiment, the on-board maintenance BIT self-test reminder, fastener inspection reminder, and manual maintenance reminder are compared and judged based on the on-board maintenance BIT self-test reminder threshold, the fastener inspection reminder threshold, and the manual maintenance reminder threshold, respectively. When the equipment accumulates fatigue damage... , as well as When the thresholds for onboard maintenance BIT self-test reminder, fastener inspection reminder, and / or manual maintenance reminder are reached, the microcontroller sends an inspection and maintenance reminder message to the avionics system via the airborne network.

[0059] Figure 1 This is a schematic diagram of the thermal vibration detection circuit provided in an embodiment of the present invention, including accelerometers 1-5 and I.2 The C-bus circuit forms a vibration measurement module, the thermistor 1, thermistor 2 and the driving acquisition circuit form a temperature measurement module, and the microcontroller acquires the temperature through the analog interface.

[0060] Figure 2 This is a schematic diagram of the layout of an accelerometer and a thermistor in a thermal vibration detection circuit provided by an embodiment of the present invention. The accelerometers, used to measure the amount of vibration experienced by the device under test, are symmetrically arranged at the four corners and the center of the printed circuit board. The thermistors are arranged in locations on the device that are prone to heat generation and in locations where the temperature is less affected by the heat generated during device operation.

[0061] Five accelerometer samples were low-pass filtered to remove outliers caused by noise. The filtered five samples were then sorted from largest to smallest, and the second sample was taken as the measured value. Temperature change was measured. When the temperature measurement results of the two thermistors are taken, the maximum value is taken.

[0062] The predictive maintenance method for equipment, implemented using the thermal vibration detection circuit described above, includes: establishing a predictive maintenance model; calculating predictive maintenance information for various parts of the equipment based on equipment temperature data, equipment vibration data, and cumulative operating time; including predicted lifespan of thermal vibration-sensitive components, on-board maintenance BIT self-test reminders, fastener inspection reminders, and manual maintenance reminders. Figure 3 As shown.

[0063] Calculate temperature fatigue damage using equipment temperature data. Calculated by the following formula,

[0064]

[0065] In this embodiment, the sampling frequency is selected as 50Hz, i.e., the sampling time interval. It takes 20ms. The critical value for thermal fatigue damage is taken as 5℃ / min. When the collected and calculated data... At that time, that is S T If the value is not equal to 0, the microcontroller will... S T Stored in memory.

[0066] Vibration fatigue damage is calculated using equipment vibration data. Calculated by the following formula,

[0067]

[0068] In this embodiment, the chip mass in the device is sensitive to thermal shock. The value is 5g, which is the critical value for vibration fatigue damage. The value is 150m / s 2 That is, when the vibration acceleration is less than 150 m / s² 2 When the vibration acceleration is greater than 150 m / s², fatigue damage is not considered. Conversely, when the vibration acceleration is greater than 150 m / s², fatigue damage is not considered. 2 At that time, the microcontroller will... S v Stored in memory.

[0069] Fatigue damage is obtained by summing vibration fatigue damage and temperature fatigue damage, i.e. .

[0070] Based on the stress-life characteristics of thermal shock sensitive elements, their predicted life is calculated as follows: ,in, To predict lifespan, For design life, In this embodiment, the conversion factor is... Take 1. Through temperature fatigue damage and vibration fatigue damage Summing yields its cumulative amount , Combined with the above formula, the predicted lifespan of thermally sensitive elements can be calculated.

[0071] Set the on-machine maintenance BIT self-test reminder threshold, fastener inspection reminder threshold, and manual maintenance reminder threshold. Each threshold is derived from design parameters or experiments. When the equipment accumulates fatigue damage... , , When each threshold is reached, a message is sent to the avionics system via the airborne network to remind ground maintenance personnel to perform further maintenance and testing on the equipment in a timely manner.

[0072] The circuit and method described in this invention can effectively measure and monitor the thermal vibration environment of airborne equipment, and calculate the stress fatigue damage status of the equipment in real time through a predictive maintenance model. This solves the problem of inaccurate stress fatigue damage prediction in traditional methods. By reporting equipment fatigue information via the airborne network bus, ground maintenance personnel can perform early maintenance and inspection of airborne equipment, improving flight safety.

[0073] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A thermal vibration detection circuit, characterized in that, include: Vibration measurement module, temperature measurement module, microcontroller, and memory; The vibration measurement module is used to measure the amount of vibration experienced by the device under test; it consists of five accelerometers respectively located at the four corners and the center of the printed circuit board of the device under test. The temperature measurement module is used to measure the temperature of the device under test, and includes at least two thermistors and driving and acquisition circuits; the thermistors are distributed in the heat-prone areas and the room temperature area of ​​the printed circuit board. The memory is used to store flight time, equipment vibration and temperature data, material thermal fatigue stress data, and predictive maintenance model data; The microcontroller is used to acquire real-time acceleration and real-time temperature measured by the vibration measurement module and the temperature measurement module, and calculates the current thermal fatigue stress information through a mathematical model using the data stored in the memory; wherein, the thermal fatigue stress information includes temperature fatigue damage. and vibration fatigue damage ; The temperature fatigue damage Calculated by the following formula, in, for Temperature reading difference within a time period The sampling time interval, That is, the rate of temperature change within the sampling time interval. The critical value for thermal fatigue damage is defined as the rate of temperature change being less than the critical value for thermal fatigue damage. The temperature fatigue damage is 0, meaning that the temperature change rate is considered to be no level that will cause temperature fatigue damage to the equipment. Vibration fatigue damage Calculated by the following formula: in, The real-time acceleration value of the device obtained by the accelerometer. For the quality of chips in equipment that are sensitive to thermal shock; This is the critical value for vibration fatigue damage; when the real-time acceleration is less than the critical value for vibration fatigue damage... The vibration fatigue stress is 0, which means that the vibration level will not cause vibration fatigue damage to the equipment. Thermal fatigue stress information is characterized by the summation of vibration fatigue damage and temperature fatigue damage. ; in: S This is thermal fatigue stress information.

2. The thermal vibration detection circuit according to claim 1, characterized in that, After the microcontroller collects the sampled values ​​of each accelerometer, it performs low-pass filtering to remove measurement singularities caused by noise. The five filtered sampled values ​​are sorted from largest to smallest, and the second sampled value is taken as the measurement value.

3. A predictive maintenance method for equipment based on the thermal vibration detection circuit described in claim 1 or 2, characterized in that, Includes the following steps: Establish a predictive maintenance model to calculate the thermal vibration fatigue stress information of various parts of the tested equipment using real-time temperature data, historical temperature data, real-time vibration data, historical vibration data, and cumulative operating time. Predictive maintenance information is obtained based on thermal shock fatigue stress information; The device under test is maintained based on the predictive maintenance information; The predictive maintenance information includes predicted lifespan of equipment thermal vibration sensitive components, on-board maintenance BIT self-test reminders, fastener inspection reminders, and manual maintenance reminders.

4. The predictive maintenance method for equipment according to claim 3, characterized in that, The predicted lifetime of the device under test is characterized as follows: ,in, To predict lifespan, For design life, The conversion factor is determined by the stress-life characteristics.

5. The predictive maintenance method for equipment according to claim 4, characterized in that, The on-board maintenance BIT self-check reminder, fastener inspection reminder, and manual maintenance reminder are compared and judged based on the on-board maintenance BIT self-check reminder threshold, fastener inspection reminder threshold, and manual maintenance reminder threshold, respectively. When the equipment accumulates fatigue damage... , as well as When the thresholds for onboard maintenance BIT self-test reminder, fastener inspection reminder, and / or manual maintenance reminder are reached, the microcontroller sends an inspection and maintenance reminder message to the avionics system via the airborne network.

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