Fully automatic accelerometer testing method based on high-precision AD conversion circuit

Abstract

The present invention relates to the field of acceleration measurement technology, and in particular to a fully automatic accelerometer testing method based on a high-precision AD conversion circuit. The method comprises: establishing a target current-temperature rise relationship model corresponding to the resistor to be tested based on several sets of current and temperature test data of the resistor to be tested; when it is detected that the current current of the target resistor is greater than a preset current threshold, calculating the current operating temperature of the target resistor based on the target current-temperature rise relationship model and the current ambient temperature; and calculating the current resistance influence coefficient corresponding to the target resistor in combination with the real temperature of the resistor detected in real time. Furthermore, the total resistance influence coefficient is calculated in combination with an aging coefficient, thereby calculating the current actual resistance value of the target resistor. The present invention improves the acquisition accuracy of the voltage signal by optimizing the measurement method of the actual resistance value of the resistor, thereby improving the measurement accuracy of the accelerometer.

Description

Technical Field

[0001] The present invention relates to the technical field of acceleration measurement, and in particular to a full-automatic accelerometer testing method based on a high-precision AD conversion circuit. Background Art

[0002] Accelerometers are sensors that measure an object's acceleration and are widely used in a variety of fields. For example, applications such as automotive navigation, drone monitoring, and smart wristbands all place high demands on accelerometer accuracy. Conventional accelerometer detection methods convert the accelerometer's output current signal into a voltage signal using a resistor, followed by direct digital conversion using an analog-to-digital converter. However, the complexity of this process can lead to reduced measurement accuracy.

[0003] Currently, the invention patent application with publication number CN119945437A discloses a high-precision pseudo-differential digital conversion circuit and operating method for accelerometer signals, including an IV conversion circuit, a pseudo-differential amplifier circuit, and an AD conversion circuit. A power supply with strong anti-interference capabilities is used as a reference level in the AD conversion circuit to improve the conversion accuracy of the AD conversion circuit and enhance the acceleration measurement accuracy. However, the above technical solution does not take into account the impact of resistance factors on measurement accuracy, and the measurement accuracy of the accelerometer still needs to be improved. Summary of the Invention

[0004] In response to the above technical problems, the present invention provides a fully automatic accelerometer testing method based on a high-precision AD conversion circuit. By optimizing the measurement method of the actual resistance value of the resistor, the acquisition accuracy of the voltage signal can be improved, thereby improving the measurement accuracy of the accelerometer.

[0005] The present invention provides a fully automatic accelerometer testing method based on a high-precision AD conversion circuit, comprising the following steps:

[0006] S100 , establishing a target current-temperature rise relationship model corresponding to the resistor to be measured based on several sets of current and temperature test data of the resistor to be measured.

[0007] S200, when it is detected that the current current of the target resistor is greater than a preset current threshold, the temperature rise corresponding to the current current is obtained according to a target current-temperature rise relationship model, and the current operating temperature of the target resistor is obtained based on the current ambient temperature.

[0008] S300: Calculate the current resistance influence coefficient f corresponding to the target resistor based on the current operating temperature of the target resistor and the real temperature of the resistor detected in real time, and calculate the total resistance influence coefficient Q corresponding to the target resistor based on the current resistance influence coefficient f and the aging coefficient k corresponding to the target resistor obtained in advance.

[0009] S400 , calculating a current actual resistance value of the target resistor according to a total resistance influence coefficient Q corresponding to the target resistor and the nominal resistance value of the target resistor.

[0010] S500 , obtaining a measurement value of the accelerometer according to the current actual resistance value of the target resistor, the current current of the target resistor, and a preset AD conversion circuit.

[0011] The present invention has at least the following beneficial effects:

[0012] The present invention provides a fully automatic accelerometer testing method based on a high-precision AD conversion circuit. First, based on several groups of current and temperature test data of the resistor to be tested, a target current-temperature rise relationship model corresponding to the resistor to be tested is established, which can better characterize the relationship between current and temperature rise. Then, when measuring acceleration, when it is detected that the current current of the target resistor is greater than a preset current threshold, the current operating temperature of the target resistor is calculated based on the target current-temperature rise relationship model and the current ambient temperature. The temperature calculated in this way can better reflect the current actual working state of the resistor. Combined with the real temperature of the resistor detected in real time, the current resistance influence coefficient corresponding to the target resistor is calculated, and then combined with the aging coefficient to obtain the total resistance influence coefficient. By combining the two obtained temperatures and introducing the aging coefficient for comprehensive analysis, the obtained total resistance influence coefficient is made more reliable, and the current actual resistance value of the target resistor is calculated. The present invention can improve the acquisition accuracy of the voltage signal by optimizing the measurement method of the actual resistance value of the resistor, thereby improving the measurement accuracy of the accelerometer. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0014] Figure 1 This is a flow chart of a fully automatic accelerometer testing method based on a high-precision AD conversion circuit provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0015] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0016] The present invention provides a fully automatic accelerometer testing method based on a high-precision AD conversion circuit, such as Figure 1 As shown, the method includes the following steps:

[0017] S100 : Based on several sets of current and temperature test data for the resistor under test, a target current-temperature rise relationship model corresponding to the resistor under test is established. In a specific implementation, to minimize the effects of age on the resistor, the resistor under test is an unused factory-made resistor, and each set of current and temperature tests is performed at a fixed interval, for example, five minutes.

[0018] In a specific embodiment, step S100 includes the following steps:

[0019] S101, based on several sets of current and temperature test data of the resistor to be measured, obtain the temperature rise corresponding to each test current of the resistor to be measured; it can be understood that: the temperature rise refers to the difference between the operating temperature of the resistor and the ambient temperature. The operating temperature of the resistor can be directly measured by using a temperature sensor close to the resistor to be measured or calculated through the power loss and thermal resistance of the resistor. The above two measurement methods are both existing technologies and will not be repeated here.

[0020] S102, each test current of the resistor to be tested and the temperature rise corresponding to each test current are respectively substituted into the preset current-temperature rise relationship model to be processed ΔT=a×e bI -a, the values of a and b are obtained after processing; where ΔT refers to the temperature rise corresponding to the test current, I represents the test current of the resistor to be measured, a represents the amplitude adjustment coefficient, and b represents the horizontal scaling factor.

[0021] Furthermore, in step S102, the values of a and b are obtained by the following steps:

[0022] S1021: Receive the value range of the amplitude adjustment coefficient and the horizontal scaling factor input by the user, and construct a target grid based on the value range of the amplitude adjustment coefficient and the horizontal scaling factor. For example, the user can determine the approximate value range based on multiple experiments and observation of the curve trajectory of the model.

[0023] S1022 : Generate an intermediate current-temperature rise relationship model for the values of the amplitude adjustment coefficient and the horizontal scaling factor corresponding to any grid point in the target grid.

[0024] S1023, based on several groups of test currents and temperature rises, and according to the curve corresponding to the intermediate current-temperature rise relationship model, the loss value corresponding to the grid point itself is calculated; this can be understood as: the loss value is calculated based on the difference between each group of test currents and temperature rises and the corresponding points on the curve corresponding to the intermediate current-temperature rise relationship model.

[0025] Specifically, the loss value L corresponding to the j-th grid pointj Meet the following conditions:

[0026] , where n is the number of grid points, is the predicted value of the temperature rise of the jth grid point by the intermediate current-temperature rise relationship model, ΔT j is the measured value of the temperature rise corresponding to the j-th grid point.

[0027] S1024 , based on the loss value corresponding to each grid point, the amplitude adjustment coefficient and the horizontal scaling factor corresponding to the grid point with the smallest loss value are used as the values of a and b respectively.

[0028] As described above, several grid points are constructed based on several sets of current and temperature rise test data, and the loss value corresponding to each grid point is calculated. The target current-temperature rise relationship model thus determined has the smallest comprehensive error with all measurement data, and the obtained model is more accurate and has better prediction effect.

[0029] S103 , substituting the value of the amplitude adjustment coefficient a into the current-temperature rise relationship model to be processed to obtain a target current-temperature rise relationship model.

[0030] As mentioned above, since there is a certain changing relationship between current and temperature rise, for example, in the low current stage, as the current increases, the temperature rise increases and the increasing rate is relatively slow, while in the high current stage, as the current increases, the increasing rate of temperature rise will accelerate sharply, which is in line with the changing trend of the exponential function. Therefore, the above-mentioned current-temperature rise relationship model function to be processed is constructed, which can better characterize the relationship between current and temperature rise, and provides a basis for the subsequent corresponding numerical value search.

[0031] S200, when it is detected that the current current of the target resistor is greater than a preset current threshold, the temperature rise corresponding to the current current is obtained according to a target current-temperature rise relationship model, and the current operating temperature of the target resistor is obtained based on the current ambient temperature.

[0032] Specifically, the current operating temperature of the target resistor is the sum of the current ambient temperature and the temperature rise corresponding to the current current. This means the current operating temperature of the target resistor is the temperature generated by the current current in addition to the current ambient temperature. For example, when the ambient temperature is 25°C, the high current will cause the resistor's operating temperature to reach 30°C.

[0033] As described above, the current operating temperature of the target resistor is obtained by superimposing the ambient temperature and the temperature rise, so that the obtained operating temperature can better reflect the current working condition of the resistor. If the working temperature of the resistor is directly detected by a sensor, when the current increases sharply, the data obtained is close to the surface temperature of the resistor, but cannot fully reflect the true internal temperature state of the resistor. Therefore, the above method is used to obtain the current operating temperature of the target resistor.

[0034] Furthermore, the preset current threshold is obtained through the following steps:

[0035] S10 , determining, based on several groups of current and temperature test data of the resistor to be measured, several test currents whose corresponding temperature rise measurement values are less than a preset temperature rise threshold.

[0036] S20: Taking the maximum current value among the multiple test currents as a preset current threshold.

[0037] S300: Calculate the current resistance influence coefficient f corresponding to the target resistor based on the current operating temperature of the target resistor and the real temperature of the resistor detected in real time, and calculate the total resistance influence coefficient Q corresponding to the target resistor based on the current resistance influence coefficient f and the aging coefficient k corresponding to the target resistor obtained in advance.

[0038] Specifically, the current resistance influence coefficient f corresponding to the target resistance is obtained through the following steps:

[0039] S301 , calculating a current resistor influence temperature t corresponding to the target resistor based on the current operating temperature of the target resistor and the real temperature of the resistor detected in real time.

[0040] The current resistance-affected temperature t corresponding to the target resistance meets the following conditions:

[0041] t=w1t1+w2t2, where w1 and w2 are weight factors corresponding to the current operating temperature of the target resistor and the real temperature of the resistor detected in real time, respectively. t1 is the current operating temperature of the target resistor, t2 is the real temperature of the resistor detected in real time, w1+w2=1, and w1<w2.

[0042] When obtaining the aging coefficient k corresponding to the target resistor, for example, if the initial resistance of the resistor is 100Ω and the resistance after two years of use is 105Ω, the corresponding aging coefficient is (105-100) / (100×2)×100%=2.5%. In specific implementations, other methods can also be used to calculate the aging coefficient, which will not be repeated here.

[0043] S302 , calculating a current resistance influence coefficient f corresponding to the target resistance according to the current resistance influence temperature corresponding to the target resistance.

[0044] In a preferred embodiment, the current resistance influence coefficient f corresponding to the target resistance meets the following conditions:

[0045] f=(R t -R t0 ) / (R t0 ×(t-t0))×100%, where t0 is the preset reference temperature, R tThe current resistance influence temperature corresponding to the target resistance, R t0 is the resistance value of the target resistor at t0. In a specific implementation, t0 and R t0 These are pre-obtained values.

[0046] Furthermore, the total resistance influence coefficient Q corresponding to the target resistance meets the following conditions:

[0047] Q=λf+(1-λ)k, where λ is a preset scaling factor, λ>0.5.

[0048] As mentioned above, when the current changes, the integrated temperature of the resistor will also change accordingly, and should be between the calculated operating temperature and the detected actual surface temperature. Therefore, the current resistance influence temperature obtained by the above calculation method is more reasonable, and thus the current resistance influence coefficient obtained is more reliable.

[0049] S400: Calculate the current actual resistance value of the target resistor based on the total resistance influence coefficient Q corresponding to the target resistor and the nominal resistance value of the target resistor. In a specific implementation, the current actual resistance value of the target resistor can be calculated periodically, for example, updated every 1 minute.

[0050] Specifically, the current actual resistance value R1 of the target resistor meets the following conditions:

[0051] R1=R0×(1+Q), where R0 is the nominal resistance value of the target resistor.

[0052] In another specific embodiment, when it is detected that the current current of the target resistor is not greater than the preset current threshold, the current actual resistance value of the target resistor is calculated according to the aging coefficient k corresponding to the target resistor and the nominal resistance value of the target resistor.

[0053] The current actual resistance value R2 of the target resistor meets the following conditions:

[0054] R2=R0×(1+k).

[0055] As mentioned above, by analyzing the total resistance influence coefficient, the current actual resistance value obtained is made more reliable. In addition, considering that the temperature rise of the resistor is not obvious when the current is too small, the influence of the temperature rise on the resistance value can be ignored. Only the aging coefficient is used as the resistance influence factor, which reduces the calculation complexity of the whole process.

[0056] S500 , obtaining a measurement value of the accelerometer according to the current actual resistance value of the target resistor, the current current of the target resistor, and a preset AD conversion circuit.

[0057] In a specific embodiment, step S500 includes the following steps:

[0058] S501 , obtaining a detected sampled voltage signal according to the current actual resistance value of the target resistor and the current current of the target resistor; it can be understood that the sampled voltage value is the current actual resistance value and the current current of the target resistor.

[0059] S502: digitally convert the detected sampled voltage signal through a preset AD conversion circuit to obtain an accelerometer measurement value. Those skilled in the art know the specific implementation method of obtaining the accelerometer measurement value based on the voltage signal, which will not be described in detail here.

[0060] As described above, based on the high-precision AD conversion circuit, the measurement method of the actual resistance value of the target resistor is also optimized, so that the measured resistance value is closer to the actual resistance value of the resistor during operation, thereby improving the acquisition accuracy of the voltage signal and thus improving the measurement accuracy of the accelerometer.

[0061] In summary, the present invention provides a fully automatic accelerometer testing method based on a high-precision AD conversion circuit. First, based on several groups of current and temperature test data of the resistor to be measured, a target current-temperature rise relationship model corresponding to the resistor to be measured is established, which can better characterize the relationship between current and temperature rise; then, when measuring acceleration, when it is detected that the current current of the target resistor is greater than the preset current threshold, the current operating temperature of the target resistor is calculated based on the target current-temperature rise relationship model and the current ambient temperature. The temperature calculated in this way can better reflect the current actual working state of the resistor. Combined with the real temperature of the resistor detected in real time, the current resistance influence coefficient corresponding to the target resistor is calculated, and then combined with the aging coefficient to obtain the total resistance influence coefficient. By combining the two temperatures obtained and introducing the aging coefficient for comprehensive analysis, the total resistance influence coefficient obtained is more reliable, and the current actual resistance value of the target resistor is calculated. The present invention optimizes the measurement method of the actual resistance value of the resistor, which can improve the acquisition accuracy of the voltage signal, thereby improving the measurement accuracy of the accelerometer.

[0062] Although some specific embodiments of the present invention have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It should also be understood by those skilled in the art that various modifications may be made to the embodiments without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A fully automatic accelerometer testing method based on a high-precision AD conversion circuit, characterized in that: The method comprises the following steps: S100, establishing a target current-temperature rise relationship model corresponding to the resistor to be measured based on several sets of current and temperature test data of the resistor to be measured; S200, when it is detected that the current current of the target resistor is greater than a preset current threshold, obtaining a temperature rise corresponding to the current current according to a target current-temperature rise relationship model, and obtaining a current operating temperature of the target resistor based on the current ambient temperature; S300: Calculate a current resistance influence coefficient f corresponding to the target resistor based on the current operating temperature of the target resistor and the real temperature of the resistor detected in real time, and calculate a total resistance influence coefficient Q corresponding to the target resistor based on the current resistance influence coefficient f and a previously acquired aging coefficient k corresponding to the target resistor. S400, calculating a current actual resistance value of the target resistor based on a total resistance influence coefficient Q corresponding to the target resistor and a nominal resistance value of the target resistor; S500 , obtaining a measurement value of the accelerometer according to the current actual resistance value of the target resistor, the current current of the target resistor, and a preset AD conversion circuit.

2. The fully automatic accelerometer testing method based on a high-precision AD conversion circuit according to claim 1, characterized in that: Step S100 includes the following steps: S101, obtaining a temperature rise corresponding to each test current of the resistor to be measured based on several sets of current and temperature test data of the resistor to be measured; S102, each test current of the resistor to be tested and the temperature rise corresponding to each test current are respectively substituted into the preset current-temperature rise relationship model to be processed ΔT=a×e bI -a, the values of a and b are obtained after processing; where ΔT is the temperature rise corresponding to the test current, I is the test current of the resistor to be tested, a is the amplitude adjustment coefficient, and b is the horizontal scaling factor; S103 , substituting the value of the amplitude adjustment coefficient a into the current-temperature rise relationship model to be processed to obtain a target current-temperature rise relationship model.

3. The fully automatic accelerometer testing method based on a high-precision AD conversion circuit according to claim 2, characterized in that: In step S102, the values of a and b are obtained by the following steps: S1021, receiving a value range of an amplitude adjustment coefficient and a horizontal scaling factor input by a user, and constructing a target grid according to the value range of the amplitude adjustment coefficient and the horizontal scaling factor; S1022 , generating an intermediate current-temperature rise relationship model for the values of the amplitude adjustment coefficient and the horizontal scaling factor corresponding to any grid point in the target grid; S1023, based on several sets of test currents and temperature rises, and according to a curve corresponding to an intermediate current-temperature rise relationship model, a loss value corresponding to the grid point itself is calculated; Among them, the loss value L corresponding to the j-th grid point j Meet the following conditions: , where n is the number of grid points, is the predicted value of the temperature rise of the jth grid point by the intermediate current-temperature rise relationship model, ΔT j is the measured value of the temperature rise corresponding to the j-th grid point; S1024 , based on the loss value corresponding to each grid point, the amplitude adjustment coefficient and the horizontal scaling factor corresponding to the grid point with the smallest loss value are used as the values of a and b respectively.

4. The fully automatic accelerometer testing method based on a high-precision AD conversion circuit according to claim 1, characterized in that: To obtain the preset current threshold, follow these steps: S10, determining, based on several sets of current and temperature test data of the resistor to be tested, several test currents whose corresponding temperature rise measurement values are less than a preset temperature rise threshold; S20: Taking the maximum current value among the multiple test currents as a preset current threshold.

5. The fully automatic accelerometer testing method based on a high-precision AD conversion circuit according to claim 1, characterized in that: In step S300, the current resistance influence coefficient f corresponding to the target resistance is obtained through the following steps: S301, calculating the current resistance influence temperature t corresponding to the target resistor based on the current operating temperature of the target resistor and the real temperature of the resistor detected in real time; The current resistance-affected temperature t corresponding to the target resistance meets the following conditions: t=w1t1+w2t2, where w1 and w2 are the weight factors corresponding to the current operating temperature of the target resistor and the real temperature of the resistor detected in real time, respectively. t1 is the current operating temperature of the target resistor, t2 is the real temperature of the resistor detected in real time, w1+w2=1 and w1<w2; S302, calculating a current resistance influence coefficient f corresponding to the target resistance based on the current resistance influence temperature corresponding to the target resistance; The current resistance influence coefficient f corresponding to the target resistance meets the following conditions: f=(R t -R t0 ) / (R t0 ×(t-t0))×100%, where t0 is the preset reference temperature, R t The current resistance influence temperature corresponding to the target resistance, R t0 is the resistance value of the target resistor at t0.

6. The fully automatic accelerometer testing method based on a high-precision AD conversion circuit according to claim 1, characterized in that: In step S300, the total resistance influence coefficient Q corresponding to the target resistance meets the following conditions: Q=λf+(1-λ)k, where λ is a preset scaling factor, λ>0.

5.

7. The fully automatic accelerometer testing method based on a high-precision AD conversion circuit according to claim 1, characterized in that: Step S500 includes the following steps: S501, obtaining a detected sampled voltage signal according to the current actual resistance value of the target resistor and the current current of the target resistor; S502 , performing digital conversion on the detected sampled voltage signal through a preset AD conversion circuit to obtain a measurement value of the accelerometer.

8. The fully automatic accelerometer testing method based on a high-precision AD conversion circuit according to claim 1, characterized in that: The method further comprises the steps of: When it is detected that the current current of the target resistor is not greater than the preset current threshold, the current actual resistance value of the target resistor is calculated according to the aging coefficient k corresponding to the target resistor and the nominal resistance value of the target resistor.

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