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

Abstract

The invention relates to the technical field of acceleration measurement, in particular to a full-automatic accelerometer test method based on a high-precision AD conversion circuit, and the method comprises the steps: building a target current-temperature rise relation model corresponding to a to-be-tested resistor according to a plurality of groups of current and temperature test data of the to-be-tested resistor, when it is detected that the current current of the target resistor is larger than a preset current threshold value, the current working temperature of the target resistor is calculated according to the target current-temperature rise relation model and the current environment temperature, and the current resistance influence coefficient corresponding to the target resistor is calculated by combining the real temperature of the resistor detected in real time; combining the aging coefficient to obtain a total resistance influence coefficient, and calculating the current actual resistance value of the target resistor; according to the invention, by optimizing the measurement mode of the actual resistance value of the resistor, the acquisition precision of the voltage signal can be improved, so that the measurement precision of the accelerometer is improved.

Description

Technical Field

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

[0002] An accelerometer is a sensor for measuring the acceleration of an object and is widely used in multiple fields. For example, in fields such as automotive navigation, drone monitoring, and smart bracelets, high requirements are placed on the accuracy of the accelerometer. The conventional accelerometer detection method is to directly perform digital conversion on the voltage signal obtained by converting the current signal output by the accelerometer through a resistor by an AD converter. However, due to the complex circuit in the whole process, the measurement accuracy will decrease.

[0003] Currently, as disclosed in the invention patent application with publication number CN119945437A, a high-precision accelerometer signal pseudo-differential digital conversion circuit and working method, including an I-V conversion circuit, a pseudo-differential amplification circuit, and an AD conversion circuit, uses a power supply with strong anti-interference ability as a reference level in the AD conversion circuit to improve the conversion accuracy of the AD conversion circuit, thereby improving the measurement accuracy of the acceleration. However, the above technical solution does not consider the influence of the resistance factor on the measurement accuracy, and the measurement accuracy of the accelerometer still needs to be improved. Summary of the Invention

[0004] In view of the above technical problems, the present invention provides a fully automatic accelerometer test 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 test method based on a high-precision AD conversion circuit, including the following steps: S100, based on several groups of test data of current and temperature of the resistor to be measured, establish a target current-temperature rise relationship model corresponding to the resistor to be measured.

[0006] S200, when it is detected that the current of the target resistor is greater than the preset current threshold, obtain the temperature rise corresponding to the current according to the target current-temperature rise relationship model, and obtain the current working temperature of the target resistor based on the current ambient temperature.

[0007] S300, calculate the current resistance influence coefficient f corresponding to the target resistor according to the current working temperature of the target resistor and the real-time detected true temperature of the resistor, and calculate the total resistance influence coefficient Q corresponding to the target resistor according to the current resistance influence coefficient f and the aging coefficient k corresponding to the target resistor obtained in advance.

[0008] 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.

[0009] S500. Obtain the measurement value of the accelerometer based on the current actual resistance value of the target resistor, the current of the target resistor, and a preset AD conversion circuit.

[0010] The present invention has at least the following beneficial effects: The present invention provides a fully automatic accelerometer test method based on a high-precision AD conversion circuit. First, based on several groups of test data of current and temperature 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 of the target resistor is greater than the preset current threshold, the current working temperature of the target resistor is calculated according to 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. Then, combined with the real-time detected true temperature of the resistor, the current resistance influence coefficient corresponding to the target resistor is calculated, and the total resistance influence coefficient is obtained by combining with the aging coefficient. By combining the two obtained temperatures and introducing the aging coefficient for comprehensive analysis, the obtained total resistance influence coefficient is more reliable, and thus 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, can improve the acquisition accuracy of the voltage signal, and thus improve the measurement accuracy of the accelerometer. Description of the Drawings

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0012] Figure 1 It is a flowchart of the fully automatic accelerometer test method based on a high-precision AD conversion circuit provided by the embodiments of the present invention. Detailed Embodiments

[0013] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0014] The present invention provides a fully automatic accelerometer testing method based on a high-precision AD conversion circuit, as Figure 1 shown, the method includes the following steps: S100, based on several groups of test data of current and temperature of the resistor to be measured, establish a target current-temperature rise relationship model corresponding to the resistor to be measured. In a specific implementation, in order to avoid the influence of the service life on the resistor, the resistor to be measured used is a brand-new factory resistor, and there is a certain interval between each group of current and temperature tests, for example, five minutes.

[0015] In a specific embodiment, step S100 includes the following steps: S101, based on several groups of test data of current and temperature 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 working temperature and the ambient temperature of the resistor, and the working temperature of the resistor can be directly measured by a temperature sensor closely attached 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 prior arts and will not be elaborated here.

[0016] S102, substitute each test current of the resistor to be measured and the temperature rise corresponding to each test current into the preset current-temperature rise relationship model to be processed ΔT = a×e bI -a, and obtain the values of a and b 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.

[0017] Further, in step S102, the values of a and b are also obtained through the following steps: S1021, receive the value ranges of the amplitude adjustment coefficient and the horizontal scaling factor input by the user, and construct a target grid according to the value ranges of the amplitude adjustment coefficient and the horizontal scaling factor. For example, the user can determine the approximate value ranges based on multiple experiments and observing the curve trajectory of the model.

[0018] S1022, for the values of the amplitude adjustment coefficient and the horizontal scaling factor corresponding to any grid point in the target grid, generate an intermediate current-temperature rise relationship model.

[0019] S1023, according to several groups of test currents and temperature rises, and calculate the loss value corresponding to the grid point itself according to the curve corresponding to the intermediate current-temperature rise relationship model; it can be understood that: according to 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, calculate the loss value.

[0020] Specifically, the loss value L j corresponding to the jth grid point meets the following conditions: , where n is the number of grid points, is the predicted value of the temperature rise of the j-th grid point by the intermediate current-temperature rise relationship model, and ΔT j is the measured value of the temperature rise corresponding to the j-th grid point.

[0021] S1024. Based on the loss value corresponding to each grid point, use the amplitude adjustment coefficient and the horizontal scaling factor corresponding to the grid point with the smallest loss value as the values of a and b respectively.

[0022] As described above, several grid points are constructed according to several groups of test data of current and temperature rise, and the loss value corresponding to each grid point is calculated. The target current-temperature rise relationship model determined thereby has the smallest comprehensive error with all the measurement data, and the obtained model is more accurate and has a better prediction effect.

[0023] S103. Substitute the value of the amplitude adjustment coefficient a into the current-temperature rise relationship model to be processed to obtain the target current-temperature rise relationship model.

[0024] As described above, since there is a certain variation relationship between current and temperature rise. For example, in the low current stage, as the current increases, the temperature rise increases and the increase rate is relatively slow. While in the high current stage, as the current increases, the increase rate of the temperature rise will increase sharply, which conforms to the variation trend of the exponential function. Therefore, the above 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 subsequent corresponding numerical search.

[0025] S200. When it is detected that the current of the target resistor is greater than the preset current threshold, obtain the temperature rise corresponding to the current according to the target current-temperature rise relationship model, and obtain the current working temperature of the target resistor based on the current ambient temperature.

[0026] Specifically, the current working temperature of the target resistor is the sum of the current ambient temperature and the temperature rise corresponding to the current; it can be understood that: the current working temperature of the target resistor refers to the temperature generated due to the current factor on the basis of the current ambient temperature. For example, when the ambient temperature is 25 °C, due to the high current, the working temperature of the resistor reaches 30 °C.

[0027] As described above, the current working temperature of the target resistor is obtained by superimposing the ambient temperature and the temperature rise, so that the obtained working 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 rises sharply, the obtained data is close to the surface temperature of the resistor, but cannot fully reflect the true state of the internal temperature of the resistor. Therefore, the above method is used to obtain the current working temperature of the target resistor.

[0028] Further, the preset current threshold is obtained through the following steps: S10. Determine several test currents corresponding to the measured temperature rise values less than the preset temperature rise threshold according to several groups of test data of current and temperature of the resistance to be measured.

[0029] S20. Take the maximum current value among several test currents as the preset current threshold.

[0030] S300. Calculate the current resistance influence coefficient f corresponding to the target resistance according to the current working temperature of the target resistance and the actually detected true resistance temperature, and calculate the total resistance influence coefficient Q corresponding to the target resistance according to the current resistance influence coefficient f and the aging coefficient k corresponding to the target resistance obtained in advance.

[0031] Specifically, the current resistance influence coefficient f corresponding to the target resistance is obtained through the following steps: S301. Calculate the current resistance influence temperature t corresponding to the target resistance according to the current working temperature of the target resistance and the actually detected true resistance temperature.

[0032] Among them, the current resistance influence 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 working temperature of the target resistance and the actually detected true resistance temperature respectively, t1 is the current working temperature of the target resistance, t2 is the actually detected true resistance temperature, w1 + w2 = 1 and w1 < w2.

[0033] When obtaining the aging coefficient k corresponding to the target resistance, for example, if the initial resistance value of the resistance is 100 Ω and the resistance value is 105 Ω after natural use for 2 years, the corresponding aging coefficient is (105 - 100) / (100×2)×100% = 2.5%; in a specific implementation, other methods can also be used to calculate the aging coefficient, which will not be elaborated here.

[0034] S302. Calculate the current resistance influence coefficient f corresponding to the target resistance according to the current resistance influence temperature corresponding to the target resistance.

[0035] In a preferred embodiment, 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 is the current resistance influence temperature corresponding to the target resistance, and R t0 is the resistance value of the target resistance at t0. In a specific implementation, both t0 and R t0 are values obtained in advance.

[0036] Further, the total resistance influence coefficient Q corresponding to the target resistance satisfies the following conditions: Q = λf + (1 - λ)k, where λ is a preset proportionality factor and λ > 0.5.

[0037] As described above, since the comprehensive temperature of the resistance will change with the change of current and should be between the calculated operating temperature and the detected actual surface temperature, the current resistance influence temperature obtained by the above calculation method is more reasonable, and thus the obtained current resistance influence coefficient is more reliable.

[0038] S400. Calculate the current actual resistance value of the target resistance according to the total resistance influence coefficient Q corresponding to the target resistance and the nominal resistance value of the target resistance. In a specific implementation, the current actual resistance value of the target resistance can be calculated periodically, for example, updated every 1 minute.

[0039] Specifically, the current actual resistance value R1 of the target resistance satisfies the following conditions: R1 = R0×(1 + Q), where R0 is the nominal resistance value of the target resistance.

[0040] In another specific implementation manner, when it is detected that the current current of the target resistance is not greater than the preset current threshold, calculate the current actual resistance value of the target resistance according to the aging coefficient k corresponding to the target resistance and the nominal resistance value of the target resistance.

[0041] The current actual resistance value R2 of the target resistance satisfies the following conditions: R2 = R0×(1 + k).

[0042] As described above, by analyzing the total resistance influence coefficient, the obtained current actual resistance value is more reliable, and considering that when the current is too small, the temperature rise of the resistance is not obvious, so the influence of the temperature rise on the resistance value can be ignored, and only the aging coefficient is used as the resistance influence factor, reducing the calculation complexity in the whole process.

[0043] S500. Obtain the measurement value of the accelerometer according to the current actual resistance value of the target resistance, the current current of the target resistance, and the preset AD conversion circuit.

[0044] In a specific embodiment, step S500 includes the following steps: S501. Obtain the detected sampled voltage signal according to the current actual resistance value of the target resistance and the current current of the target resistance; it can be understood that: the sampled voltage value is the current actual resistance value and the current current of the target resistance.

[0045] S502, digitally convert the detected sampled voltage signal through a preset AD conversion circuit to obtain the measurement value of the accelerometer. Those skilled in the art are aware of the specific implementation of obtaining the accelerometer measurement value from the voltage signal, which will not be elaborated here.

[0046] Based on the above-mentioned high-precision AD conversion circuit, the measurement method of the actual resistance value of the target resistor is also optimized, making the measured resistance value closer to the actual resistance value during the operation of the resistor, thereby improving the acquisition accuracy of the voltage signal and thus enhancing the measurement accuracy of the accelerometer.

[0047] In summary, the present invention provides a fully automatic accelerometer test method based on a high-precision AD conversion circuit. First, according to several groups of test data of current and temperature of the resistor to be measured, establish a target current-temperature rise relationship model corresponding to the resistor to be measured, which can better characterize the relationship between current and temperature rise; then when measuring acceleration, when it is detected that the current of the target resistor is greater than the preset current threshold, calculate the current operating temperature of the target resistor according to the target current-temperature rise relationship model and the current ambient temperature. The temperature calculated in this way can better reflect the current actual operating state of the resistor. Then, combined with the real-time detected true temperature of the resistor, calculate the current resistance influence coefficient corresponding to the target resistor, and then obtain the total resistance influence coefficient by combining with the aging coefficient. By combining the two obtained temperatures and introducing the aging coefficient for comprehensive analysis, the obtained total resistance influence coefficient is more reliable, and thus calculate the current actual resistance value of the target resistor. By optimizing the measurement method of the actual resistance value of the resistor, the present invention can improve the acquisition accuracy of the voltage signal, thereby enhancing the measurement accuracy of the accelerometer.

[0048] Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art should understand that the above examples are only for illustration and not for limiting the scope of the present invention. Those skilled in the art should also understand that various modifications can 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 includes the following steps: S100. Establish a target current-temperature rise relationship model corresponding to the resistance to be measured according to several groups of test data of current and temperature of the resistance to be measured; S200. When it is detected that the current of the target resistance is greater than the preset current threshold, obtain the temperature rise corresponding to the current according to the target current-temperature rise relationship model, and obtain the current working temperature of the target resistance based on the current ambient temperature; S300. Calculate the current resistance influence coefficient f corresponding to the target resistance according to the current working temperature of the target resistance and the actually measured real temperature of the resistance in real time, and calculate the total resistance influence coefficient Q corresponding to the target resistance according to the current resistance influence coefficient f and the aging coefficient k corresponding to the target resistance obtained in advance; S400. Calculate the current actual resistance value of the target resistance according to the total resistance influence coefficient Q corresponding to the target resistance and the nominal resistance value of the target resistance; S500. Obtain the measured value of the accelerometer according to the current actual resistance value of the target resistance, the current of the target resistance, and the preset AD conversion circuit.

2. The fully automatic accelerometer test method based on a high-precision AD conversion circuit according to claim 1, wherein Step S100 includes the following steps: S101. Obtain the temperature rise corresponding to each test current of the resistance to be measured according to several groups of test data of current and temperature of the resistance to be measured; S102, substitute each test current of the resistor to be measured and the temperature rise corresponding to each test current into the preset current-temperature rise relationship model to be processed ΔT = a×e bI -a, and obtain the values of a and b through 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; S103. Substitute the value of the amplitude adjustment coefficient a into the to-be-processed current-temperature rise relationship model to obtain the 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, wherein In step S102, the values of a and b are also obtained through the following steps: S1021. Receive the value ranges of the amplitude adjustment coefficient and the horizontal scaling factor input by the user, and construct a target grid according to the value ranges of the amplitude adjustment coefficient and the horizontal scaling factor; 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; S1023. Calculate the loss value corresponding to the grid point itself according to several groups of test currents and temperature rises and according to the curve corresponding to the intermediate current-temperature rise relationship model; Among them, the loss value L corresponding to the j-th grid point j satisfies the following conditions: , where n is the number of grid points, is the predicted value of the temperature rise of the j-th 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, use the amplitude adjustment coefficient and the horizontal scaling factor corresponding to the grid point with the smallest loss value 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, wherein Obtain the preset current threshold through the following steps: S10. Determine several test currents corresponding to the measured temperature rise values less than the preset temperature rise threshold according to several groups of test data of current and temperature of the resistance to be measured; S20. Use the maximum current value among the several test currents as the 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. Calculate the current resistance influence temperature t corresponding to the target resistance according to the current working temperature of the target resistance and the actually measured real temperature of the resistance in real time; Among them, the current resistance influence 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 working temperature of the target resistance and the actually measured real temperature of the resistance in real time respectively, t1 is the current working temperature of the target resistance, t2 is the actually measured real temperature of the resistance in real time, w1 + w2 = 1 and w1 < w2; S302. Calculate the current resistance influence coefficient f corresponding to the target resistance based on the temperature affected by the current resistance of the target resistance. Among them, 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 is the current resistance corresponding to the target resistance that affects the temperature, and R t0 is the resistance value of the target resistance at t0.

6. The fully automatic accelerometer test method based on a high-precision AD conversion circuit according to claim 1, wherein 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 proportionality factor and λ > 0.

5.

7. The fully automatic accelerometer testing method based on a high-precision AD conversion circuit according to claim 1, wherein Step S500 includes the following steps: S501. Obtain the detected sampled voltage signal based on the current actual resistance value of the target resistance and the current of the target resistance. S502. Perform digital conversion on the detected sampled voltage signal through a preset AD conversion circuit to obtain the measured value of the accelerometer.

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

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