High-temperature-resistant weighing sensor with self-calibration function

Abstract

The invention discloses a high-temperature-resistant weighing sensor with a self-calibration function, relates to the technical field of weighing sensors, and aims to solve the technical problem of measurement misalignment caused by thermal drift and sensitivity attenuation of a traditional sensor in a high-temperature environment, and the high-temperature-resistant weighing sensor comprises a sensing module, a self-calibration execution module and a signal processing and control module. By means of a real-time temperature compensation algorithm based on multi-parameter fusion, an accurate compensation model is established for the problems of zero drift and sensitivity drift in a high-temperature environment. Non-linear zero drift is corrected through a piecewise polynomial fitting function, meanwhile, the change of sensitivity along with temperature is adjusted through a temperature coefficient correction function, dynamic compensation in a full working temperature range is achieved, it is ensured that the sensor can still keep stable measurement precision in a high-temperature environment, and the measurement accuracy of the sensor is improved. The problem of measurement misalignment caused by thermal drift and sensitivity attenuation of a traditional sensor in a high-temperature environment is solved.

Description

Technical Field

[0001] This invention relates to the field of weighing sensor technology, and more specifically, to a high-temperature resistant weighing sensor with self-calibration function. Background Technology

[0002] In many fields such as industrial production, aerospace, and energy development, load cells are key metrological components whose measurement accuracy and stability directly affect production efficiency, engineering safety, and the reliability of experimental data. However, the high-temperature environments frequently encountered in these applications pose a severe challenge to traditional load cells, becoming a core bottleneck restricting their performance.

[0003] Traditional load cells are susceptible to performance drift in their core sensing components under high-temperature conditions. The physical properties of key components such as the elastic body and strain gauge change with temperature; for example, the stiffness coefficient of the elastic body fluctuates, and the sensitivity coefficient of the strain gauge shifts. This leads to nonlinear deviations in the measurement signal, and these deviations become more pronounced with increasing temperature gradients. Furthermore, high-temperature environments accelerate the aging and fatigue of sensor materials, resulting in significant sensitivity decay after prolonged use and further reducing measurement accuracy.

[0004] When sensor accuracy deteriorates, manual disassembly and offline calibration using external standard weights and other calibration equipment are necessary. This calibration method is not only cumbersome and time-consuming, severely impacting the continuity of production or experiments, but also poses safety risks in harsh environments such as high temperatures, making the calibration process extremely difficult to implement. We propose a high-temperature resistant weighing sensor with self-calibration capabilities. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art, adapt to practical needs, and provide a high-temperature resistant weighing sensor with self-calibration function to solve the technical problem of measurement inaccuracy caused by thermal drift and sensitivity decay of current traditional sensors in high-temperature environments.

[0006] To address the aforementioned technical problems, this invention provides the following technical solution: a high-temperature resistant weighing sensor with self-calibration function, comprising a sensing module, a self-calibration execution module, and a signal processing and control module. The sensing module senses the load and generates a raw electrical signal. The self-calibration execution module is connected to the sensing module and applies a known and accurate reference load to the sensing module. The signal processing and control module is connected to both the sensing module and the self-calibration execution module, and processes the raw electrical signal and controls the execution logic of the self-calibration execution module. The signal processing and control module includes an intelligent algorithm module, which incorporates a self-calibration logic unit and a temperature compensation unit. The self-calibration logic unit automatically calculates and updates the system calibration coefficient based on the signal generated by the reference load after triggering the calibration process. The temperature compensation unit dynamically compensates the signal based on temperature data.

[0007] Preferably, the sensing module includes a sensor body unit and a temperature detection unit. The sensor body unit is composed of an elastic body unit, a strain gauge unit, and a bridge unit, and is used to convert mechanical deformation into electrical signals. The temperature detection unit is used to monitor the temperature of the sensor body unit in real time.

[0008] Preferably, the self-calibration execution module includes a reference reference unit, a drive action unit, and a status feedback unit, wherein the reference reference unit is used to provide a stable built-in reference mass block. The driving action unit is used to perform loading and unloading actions on the reference reference unit under the drive of the control signal, and the status feedback unit is used to confirm and provide feedback on the loading status of the reference reference unit.

[0009] Preferably, the reference reference unit is a built-in reference mass block made of a ceramic material with an extremely low coefficient of thermal expansion. As a calibration benchmark, providing a known weight standard for self-calibration, the drive unit consists of a piezoelectric ceramic actuator and a transmission mechanism. The piezoelectric ceramic actuator receives control signals and generates precise mechanical displacement, while the transmission mechanism converts the actuator's displacement into a reference mass block. The loading or unloading action.

[0010] Preferably, the temperature detection unit employs a platinum resistance temperature sensor mounted on the elastomer unit to monitor the temperature at the sensor's core point in real time. .

[0011] Preferably, the signal processing and control module further includes a signal conditioning unit and a core computing unit. The signal conditioning unit is used to amplify and perform analog-to-digital conversion on the original electrical signal, and the core computing unit is used to run the intelligent algorithm module and store relevant parameters.

[0012] Preferably, the intelligent algorithm module includes a high-precision signal conditioning and digital filtering algorithm, a real-time temperature compensation algorithm based on multi-parameter fusion, a closed-loop feedback intelligent self-calibration algorithm, and an anti-creep and hysteresis compensation algorithm.

[0013] Preferably, it further includes a thermal management module, which provides thermal insulation and heat dissipation protection for the signal processing and control module. The thermal management module includes a thermal insulation protection unit and an active heat dissipation module. The thermal insulation protection unit is disposed between the sensing module and the signal processing and control module to isolate heat conduction. The active heat dissipation module is used to force-cool the signal processing and control module.

[0014] Preferably, it further includes a communication and interface module, which is connected to the signal processing and control module and is used for data interaction and command transmission with an external system. The communication and interface module includes a data output unit and a command input unit. The data output unit is used to output calibrated and compensated weight data to the external system, and the command input unit is used to receive remote control commands from the external system.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] 1. This invention establishes a precise compensation model for zero-point drift and sensitivity drift under high-temperature environments by employing a real-time temperature compensation algorithm based on multi-parameter fusion. Nonlinear zero-point drift is corrected using a piecewise polynomial fitting function, while a temperature coefficient correction function is used to adjust the sensitivity variation with temperature, achieving dynamic compensation across the entire operating temperature range. This design effectively offsets thermally induced errors caused by factors such as elastomer thermal expansion and strain gauge performance changes, ensuring stable measurement accuracy of the sensor even under high-temperature conditions. It solves the measurement inaccuracies caused by thermal drift and sensitivity decay in traditional sensors under high-temperature environments.

[0017] 2. This invention also utilizes a closed-loop feedback intelligent self-calibration algorithm. Through a built-in reference mass block and drive actuator, the calibration process is automatically triggered when the no-load judgment condition is met. During calibration, the sensitivity coefficient is calculated and updated by acquiring the reference load signal, replacing the traditional manual offline calibration method and completely solving the problem of sensitivity decay caused by long-term use and material fatigue. This fully automatic online calibration requires no external equipment or manual intervention, not only improving calibration efficiency but also ensuring the long-term metrological stability and reliability of the measurement results.

[0018] 3. This invention also employs an anti-creep and hysteresis compensation algorithm to specifically correct inherent errors such as creep in elastomer materials and signal hysteresis. This algorithm, in conjunction with temperature compensation and self-calibration algorithms, achieves end-to-end error correction from signal preprocessing and environmental compensation to system calibration, further reducing the deviation between measured and true values ​​and comprehensively improving the accuracy of the final output weight data. Attached Figure Description

[0019] Figure 1 This is a system block diagram of the present invention. Detailed Implementation

[0020] Example: Figure 1 As shown, the present invention relates to a high-temperature resistant weighing sensor with self-calibration function, comprising a sensing module, a self-calibration execution module, and a signal processing and control module. The sensing module is used to sense the load and generate a raw electrical signal. The self-calibration execution module is connected to the sensing module and is used to apply a known and accurate reference load to the sensing module. The signal processing and control module is connected to both the sensing module and the self-calibration execution module and is used to process the raw electrical signal and control the execution logic of the self-calibration execution module.

[0021] Furthermore, the sensing module includes a sensor body unit and a temperature detection unit. The sensor body unit consists of an elastic body unit, a strain gauge unit, and a bridge unit, used to convert mechanical deformation into an electrical signal. When the load being measured is applied to the elastic body unit, the elastic body unit undergoes mechanical deformation. According to Hooke's law, its deformation... With the load Satisfying Relationships ,in The strain gauge element is the stiffness coefficient of the elastic body element. It is attached to the elastic body element, converting the deformation of the elastic body element into a change in resistance. The resistance change rate of the strain gauge element is... Deformation of the elastic element There is a proportional relationship ,in The sensitivity coefficient of the strain gauge element. The initial length of the strain gauge. This represents the change in resistance of the strain gauge element due to deformation. The initial resistance value of the strain gauge element is given. The bridge element is composed of strain gauge elements forming a Wheatstone bridge, which ultimately outputs a millivolt-level analog signal proportional to the load. For a Wheatstone bridge in equilibrium, the output voltage is... satisfy ,in This is the input voltage of the bridge circuit.

[0022] The temperature detection unit is used to monitor the temperature of the sensor body unit in real time. The temperature detection unit uses a platinum resistance temperature sensor mounted on the elastomer unit to monitor the temperature of the core point of the sensor in real time. This provides crucial data input for subsequent temperature compensation algorithms, as high-temperature environments can easily cause sensor performance drift, and only by obtaining accurate temperature data can this drift be effectively corrected.

[0023] Furthermore, the self-calibration execution module includes a reference reference unit, a drive action unit, and a status feedback unit. The reference reference unit is used to provide a stable built-in reference mass block. The driving action unit is used to perform loading and unloading actions on the reference reference unit under the drive of the control signal. The status feedback unit is used to confirm and provide feedback on the loading status of the reference reference unit. The self-calibration execution module is connected to the sensing module and is used to apply a known and accurate reference load to the sensing module.

[0024] The reference reference unit is a built-in reference mass block made of ceramic material with an extremely low coefficient of thermal expansion. The mass block As a calibration benchmark, a known weight standard is provided for self-calibration. The drive unit consists of a piezoelectric ceramic actuator and a transmission mechanism. The piezoelectric ceramic actuator receives control signals and generates precise mechanical displacement, while the transmission mechanism converts the actuator's displacement into a reference mass block. The loading or unloading action simulates a real weighing scenario and triggers the calibration process. The status feedback unit confirms the current status of the reference mass block through the position sensor to ensure that the calibration action is performed in place and to guarantee the reliability of the calibration.

[0025] Furthermore, the signal processing and control module includes a signal conditioning unit, an intelligent algorithm module, and a core computing unit. The signal conditioning unit is used to amplify and convert the original electrical signal into an analog-to-digital signal, and is responsible for processing the weak analog signal transmitted from the sensor.

[0026] First, the weak analog signal is amplified, with an amplification factor of 1. The amplified electrical signal The amplified analog signal is then converted into a digital signal by an analog-to-digital converter (ADC) unit. This prepares for subsequent digital processing, among which... The original analog signal voltage output by the bridge unit in the sensor body unit. To represent the amplified analog signal voltage, This is the digital quantity corresponding to the analog signal after conversion. This indicates that the signal is a discrete sampled signal, where n is the sample point number (e.g., ...). (This is used to distinguish digital samples collected at different times, reflecting the time-series characteristics of the signal.)

[0027] The intelligent algorithm module has a built-in self-calibration logic unit and a temperature compensation unit. The self-calibration logic unit is used to automatically calculate and update the system calibration coefficient based on the signal generated by the reference load after the calibration process is triggered. The temperature compensation unit is used to dynamically compensate the signal based on the temperature data. The core calculation unit is used to run the intelligent algorithm module and store relevant parameters.

[0028] The intelligent algorithm unit contains a variety of algorithms to ensure accurate measurement and self-calibration of the sensor in high-temperature environments. These algorithms include high-precision signal conditioning and digital filtering algorithms, real-time temperature compensation algorithms based on multi-parameter fusion, closed-loop feedback intelligent self-calibration algorithms, and anti-creep and hysteresis compensation algorithms.

[0029] Raw analog signal output by the sensor The signal is extremely weak and mixed with high-frequency noise and power frequency interference. Direct conversion would severely affect accuracy. Therefore, the signal conditioning unit uses a programmable gain amplifier and... A high-resolution analog-to-digital converter, supplemented by digital filtering algorithms, with a gain value of [missing information]. Adaptively adjusts based on the initial signal magnitude to ensure... The full-scale range is fully utilized.

[0030]

[0031] in, for Maximum allowable input voltage For the input signal Value (root mean square value of the original signal). For the safety factor (and the stiffness coefficient of the elastic body) Unrelated; this is a dimensionless constant, usually taken as... (used to avoid signal saturation distortion).

[0032] To suppress high-frequency noise, an FIR filter is used, and its output... From the present and the past Weighted calculation of input samples:

[0033]

[0034] in, The filter coefficients are designed and determined based on the cutoff frequency and stopband attenuation requirements. for Sampled value, The order-related parameters of the FIR filter (non-negative integers, representing the total number of samples involved in the calculation minus 1). For the summation variable (taking values ​​from 0 to ... (used for traversing samples) for The output of the first The digitally sampled signal, through adaptive gain control and high-performance digital filtering, significantly improves the signal-to-noise ratio. This laid a high-quality data foundation for subsequent accurate compensation and calculation.

[0035] High temperature at the core of the sensor This leads to the strain gauge sensitivity coefficient ( The changes in strain gauge sensitivity coefficient (dimensionless) with temperature, the thermal expansion of the elastomer, and material creep introduce complex temperature drift (including zero-point drift). Zero-point drift voltage and sensitivity drift as a function of temperature (The sensitivity coefficient is a function of temperature). The temperature compensation unit in the intelligent algorithm module utilizes temperature data monitored in real time by the built-in temperature sensor. It executes a high-precision composite compensation algorithm.

[0036] Among them, zero-point drift The relationship with temperature is non-linear; a piecewise polynomial is used for high-precision fitting.

[0037]

[0038] in, These are the polynomial fitting coefficients (dimensionless constants) determined through a global temperature calibration experiment, where... The value is a non-negative integer. These correspond to the constant, linear, quadratic, and cubic coefficients of the polynomial, respectively, and the optimal fitting strategy is adopted for different temperature ranges. These are the first and second temperature ranges, respectively, which together cover the entire operating temperature range of the sensor.

[0039] The sensitivity variation with temperature is also modeled and compensated for:

[0040]

[0041] in, Reference temperature The nominal sensitivity, the reference sensitivity calibrated by the sensor at the factory. The reference temperature for sensitivity calibration is usually room temperature. , These are the first-order and second-order sensitivity temperature coefficients, respectively.

[0042] Intermediate weight value after temperature and filter compensation:

[0043]

[0044] This is the intermediate weight value after temperature and filter compensation. To represent the filtered signal voltage after processing by the FIR digital low-pass filter, the corresponding formula is... The sampled value after the signal stabilizes. To represent the real-time temperature based on the sensor The calculated zero-point drift voltage, To represent the real-time temperature based on the sensor The corrected sensor sensitivity coefficient, this composite compensation model can accurately characterize the sensor's drift characteristics across the entire temperature range, and effectively suppress thermal errors through real-time calculation, enabling the sensor to maintain high-precision output over a wide temperature range.

[0045] The present invention integrates a built-in reference mass block controlled by a piezoelectric ceramic actuator. A closed-loop control algorithm is executed by a self-calibrating logic unit.

[0046] Calibration trigger condition determination (continuously monitored by the core computing unit):

[0047]

[0048] in, For a very small weight threshold, such as full scale This ensures that the sensor is essentially unloaded before the calibration process begins.

[0049] Calibration execution and coefficient update:

[0050] Drive action unit loads reference mass block .

[0051] After the status feedback unit confirms that the loading is in place, the signal conditioning unit acquires the stable output signal at this time. .

[0052] The self-calibrating logic unit calculates new, more accurate sensitivity coefficients. (Updated accuracy and sensitivity coefficients):

[0053]

[0054] The drive unit unloads the reference mass block, and the calibration is complete.

[0055] The final output is the precise weight value:

[0056]

[0057] in, To represent the stable output signal voltage acquired by the signal conditioning unit after the reference mass block is loaded during the calibration process, For real-time temperature Calculated zero-point drift voltage, To represent the standard mass of the built-in reference mass block, The original sensitivity coefficient, based on real-time temperature correction before calibration, will be... Replacement to eliminate sensitivity decay errors caused by long-term use. This is the final, precise weight value after the entire process. This is the filtered signal voltage after processing by the FIR filter.

[0058] This algorithm enables fully automatic, online, and closed-loop self-calibration without the need for manual intervention or external equipment. It completely solves the problem of sensitivity degradation caused by long-term use, overload, or material fatigue of sensors in harsh environments such as high temperatures, ensuring the long-term metrological stability and reliability of measurements.

[0059] Furthermore, it also includes a thermal management module, which provides thermal insulation and heat dissipation protection for the signal processing and control module, enabling it to operate within the rated temperature range. The thermal management module includes a thermal insulation protection unit and an active heat dissipation module. The thermal insulation protection unit is disposed between the sensing module and the signal processing and control module to isolate heat conduction, and the active heat dissipation module is used to forcibly cool the signal processing and control module.

[0060] The function of the thermal management module is to solve the problem of damage to electronic components caused by high temperature environment, and to create a stable operating temperature. The active heat dissipation module can be equipped with a cooling system such as water cooling jacket or air cooling device (optional) to provide additional cooling for signal processing and control modules. When the thermal insulation protection effect is insufficient, it further ensures that the module operates within the rated temperature range.

[0061] Furthermore, it also includes a communication and interface module, which is connected to the signal processing and control module and is used to interact with external systems for data and transmit commands. The communication and interface module includes a data output unit and a command input unit. The data output unit is used to output calibrated and compensated weight data to the external system, and the command input unit is used to receive remote control commands from the external system.

[0062] The data output unit outputs the calibrated and compensated final weight data via a digital communication interface (such as RS-485 or Ethernet). .

[0063] The embodiments disclosed in this invention are preferred embodiments, but are not limited thereto. Those skilled in the art can easily understand the spirit of this invention based on the above embodiments and make different extensions and variations, but as long as they do not depart from the spirit of this invention, they are all within the protection scope of this invention.

Claims

1. A high-temperature resistant weighing sensor with self-calibration function, characterized in that, It includes a sensing module, a self-calibration execution module, and a signal processing and control module; The sensing module is used to sense the load and generate raw electrical signals; The self-calibration execution module is connected to the sensing module and is used to apply a known and accurate reference load to the sensing module. The signal processing and control module is connected to the sensing module and the self-calibration execution module respectively, and is used to process the raw electrical signal and control the execution logic of the self-calibration execution module. The signal processing and control module includes an intelligent algorithm module, which has a built-in self-calibration logic unit and a temperature compensation unit. The self-calibration logic unit is used to automatically calculate and update the system calibration coefficient based on the signal generated by the reference load after the calibration process is triggered. The temperature compensation unit is used to dynamically compensate the signal based on the temperature data.

2. A high-temperature resistant weighing sensor with self-calibration function according to claim 1, characterized in that, The sensing module includes a sensor body unit and a temperature detection unit. The sensor body unit is composed of an elastic body unit, a strain gauge unit and a bridge unit, and is used to convert mechanical deformation into electrical signals. The temperature detection unit is used to monitor the temperature of the sensor body unit in real time.

3. A high-temperature resistant weighing sensor with self-calibration function according to claim 2, characterized in that, The self-calibration execution module includes a reference unit, a drive action unit, and a status feedback unit; The reference unit is used to provide a stable built-in reference mass block. ; The driving action unit is used to perform loading and unloading actions on the reference reference unit under the drive of control signals; The status feedback unit is used to confirm and provide feedback on the loading status of the reference unit.

4. A high-temperature resistant weighing sensor with self-calibration function according to claim 3, characterized in that, The reference reference unit is a built-in reference mass block made of ceramic material with an extremely low coefficient of thermal expansion. As a calibration benchmark, it provides a known weight standard for self-calibration; The driving unit consists of a piezoelectric ceramic actuator and a transmission mechanism. The piezoelectric ceramic actuator receives control signals and generates precise mechanical displacement, while the transmission mechanism converts the actuator's displacement into a motion relative to a reference mass block. The loading or unloading action.

5. A high-temperature resistant weighing sensor with self-calibration function according to claim 3, characterized in that, The temperature detection unit employs a platinum resistance temperature sensor mounted on the elastomer unit for real-time monitoring of the temperature at the sensor's core point. .

6. A high-temperature resistant weighing sensor with self-calibration function according to claim 1, characterized in that, The signal processing and control module also includes a signal conditioning unit and a core computing unit; The signal conditioning unit is used to amplify and convert the original electrical signal into an analog-to-digital signal; The core computing unit is used to run the intelligent algorithm module and store relevant parameters.

7. A high-temperature resistant weighing sensor with self-calibration function according to claim 1, characterized in that, The intelligent algorithm module includes a high-precision signal conditioning and digital filtering algorithm, a real-time temperature compensation algorithm based on multi-parameter fusion, a closed-loop feedback intelligent self-calibration algorithm, and an anti-creep and hysteresis compensation algorithm.

8. A high-temperature resistant weighing sensor with self-calibration function according to claim 1, characterized in that, It also includes a thermal management module, which provides thermal insulation and heat dissipation protection for the signal processing and control module; The thermal management module includes a thermal insulation protection unit and an active heat dissipation module; The heat insulation protection unit is disposed between the sensing module and the signal processing and control module to isolate heat conduction; The active heat dissipation module is used to forcibly cool the signal processing and control module.

9. A high-temperature resistant weighing sensor with self-calibration function according to claim 1, characterized in that, It also includes a communication and interface module, which is connected to the signal processing and control module and is used to interact with external systems for data and transmit commands. The communication and interface module includes: a data output unit and an instruction input unit; The data output unit is used to output calibrated and compensated weight data to an external system; The instruction input unit is used to receive remote control instructions from external systems.

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