Full-automatic calibration control method and system for metering tank scale

Abstract

According to the full-automatic calibration control method and system for the metering tank scale, a complete closed-loop control system is constructed, the calibration precision, efficiency and automation degree are remarkably improved, environment parameters such as the temperature, the hydraulic oil state and the system pressure are monitored in real time through application of a multi-source compensation algorithm, and the calibration accuracy is improved. The target pressure value is dynamically corrected, so that system deviation caused by external factors, such as oil cylinder deformation or hydraulic oil volume fluctuation caused by temperature change, is effectively offset, and the stability and accuracy of load output are ensured; and S4, controlling the hydraulic control module to output an accurate load based on the corrected control instruction, and comparing the indicating value of the standard sensor with the indicating value of the metering tank to finish the final verification of calibration, thereby solving the problem that an existing metering tank calibration device lacks an automatic compensation mechanism for error sources such as temperature fluctuation, hydraulic oil leakage and element drift, and improving the calibration accuracy. And the calibration precision is easily influenced by environmental factors and the like, so that the calibration error is increased.

Description

Technical Field

[0001] This invention belongs to the field of metrology tank calibration technology, specifically relating to a fully automatic calibration control method and system for metrology tank scales. Background Technology

[0002] Measuring vessels, also known as reaction vessels or material tanks, are widely used in petroleum, chemical, rubber, agriculture, dye, pharmaceutical, and food industries. They are common and widely used measuring devices in industrial development. Because measuring vessels are measuring instruments, their weighing accuracy needs to be calibrated periodically. This involves calibrating the weighing scales attached to the measuring vessel to ensure that the company's legitimate economic interests are not compromised in terms of production costs, cost control, and economic output.

[0003] For example, patent application CN202321127487.0 discloses a calibration device for a measuring vessel. This device uses a mechanical structure to load and calibrate the weighing sensor of the measuring vessel, replacing the traditional weight loading method and improving calibration efficiency to a certain extent.

[0004] However, due to the lack of an automatic compensation mechanism for error sources such as temperature fluctuations, hydraulic oil leakage, and component drift, its calibration accuracy is easily affected by environmental factors, leading to increased calibration errors. At the same time, it still relies on manual intervention, making it impossible to achieve closed-loop control of the entire process. The calibration time is long and it is difficult to adapt to the rapid debugging of metering tanks with different ranges, resulting in technical problems such as low calibration accuracy and insufficient automation. Summary of the Invention

[0005] To address the technical problems in the background art, where existing metering tank calibration devices lack automatic compensation mechanisms for error sources such as temperature fluctuations, hydraulic oil leaks, and component drift, making their calibration accuracy susceptible to environmental factors and leading to increased calibration errors; furthermore, they rely on manual intervention, making it impossible to achieve closed-loop control throughout the entire process, resulting in long calibration times and difficulty in adapting to rapid debugging of metering tanks with different ranges, leading to low calibration accuracy and insufficient automation, this invention provides a fully automatic calibration control method and system for metering tank scales.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a fully automatic calibration control method for a metering tank scale, comprising: S1: Obtain the target load mass value, determine multiple calibration points based on the range of the metering tank, and calculate the target pressure value that the calibration system needs to output based on the calibration points; S2: The hydraulic cylinder is extended and retracted by the hydraulic control module to apply a load corresponding to the target pressure value to the standard sensor, while the reading of the weighing sensor of the metering tank is collected at the same time. S3: Real-time monitoring of environmental parameters, including temperature, hydraulic oil status and system pressure, based on and applying a multi-source compensation algorithm to correct the target pressure value and generate corrected control commands; S4: Based on the corrected control command, control the hydraulic control module to output a precise load, and compare the reading of the standard sensor of the calibration system with the reading of the weighing sensor of the metering tank to complete the calibration; S5: Repeat steps S2 to S4 to implement the automatic calibration process for lift and descent, and output the calibration results.

[0007] Optionally, in step S1, the target pressure value is obtained as follows: The target load mass corresponding to the calibration point. It is the acceleration due to gravity. The target pressure value needs to be output to calibrate the system.

[0008] Optionally, in step S3, the multi-source compensation algorithm includes at least one of cylinder temperature compensation, hydraulic oil expansion compensation, electro-hydraulic valve temperature compensation, and hydraulic oil leakage compensation. The application of the multi-source compensation algorithm is achieved through the following steps: S31: Collects real-time temperature data, including cylinder operating temperature, hydraulic oil temperature, and electro-hydraulic valve temperature; S32: Calculate the cylinder deformation compensation pressure, hydraulic oil expansion pressure deviation, and electro-hydraulic valve current correction amount based on temperature deviation; S33: Calculate the pressure loss caused by hydraulic oil leakage based on system pressure; S34: Coordinates and integrates all compensation quantities to generate corrected PID setpoint pressure and control current.

[0009] Optionally, in step S32, the cylinder temperature compensation is achieved using the following model: Hydraulic cylinder axial deformation model: ΔL = α·L0·ΔT; Compensation pressure model: ΔF comp =K·α·L0·(T T0); Where α is the coefficient of thermal expansion of the cylinder material, L0 is the effective length of the cylinder, ΔT is the temperature deviation, K is the system stiffness coefficient, T is the real-time temperature data, T0 is the standard working temperature, and ΔT = T - T0.

[0010] Optionally, in step S32, the cylinder temperature compensation is achieved using the following model: Hydraulic oil volume expansion: ΔV oil =γ·V0·ΔT; Pressure deviation model: ΔP oil =(γ·ΔT) / β; Where γ is the hydraulic oil volume expansion coefficient, V0 is the system closed volume, β is the hydraulic oil compressibility coefficient, and ΔT is the temperature deviation.

[0011] Optionally, in step S32, the cylinder temperature compensation is achieved using the following model: Current correction amount: ΔI valve =K I ·ΔT valve Final control current: I control_final =I ref +ΔI valve Among them, K I ΔT is the current-temperature compensation coefficient. valve Temperature deviation of electro-hydraulic valve; I ref This is the reference control current at the standard operating temperature.

[0012] Optionally, in step S33, the cylinder temperature compensation is achieved using the following model: Leakage flow model: Q leak =C L ·P·e k·ΔT Pressure loss model: ΔP leak =Q leak / β Among them, C L denoted as the leakage coefficient, P as the real-time system pressure, k as the viscosity-temperature coefficient, β as the hydraulic oil compressibility coefficient, and ΔT as the temperature deviation.

[0013] Optionally, in step S4, the generation of the control command is based on PLC programming, and closed-loop control logic is constructed through the CodeSys environment, integrating PID algorithm to adjust the hydraulic pump and electro-hydraulic valve.

[0014] Optionally, in step S5, the automatic calibration process includes repeatability calibration and indication error calibration, wherein the indication error calibration is performed in the order of rise and fall.

[0015] Secondly, the present invention provides a fully automatic calibration control system for a metering tank scale, which is used to implement the above-mentioned fully automatic calibration control method for a metering tank scale, including a hydraulic control module, a sensor module and a software control module; The sensor module is used to drive the hydraulic cylinder to extend and retract, and to apply a load corresponding to the target pressure value to the standard sensor. The hydraulic control module is used to collect the readings of the weighing sensor of the metering tank, monitor environmental parameters in real time, including temperature, hydraulic oil status and system pressure, and transmit them to the software control module. The software control module is used to generate corrected control commands and, based on the corrected control commands, controls the hydraulic control module to output a precise load. The calibration is completed by comparing the readings of the standard sensor in the calibration system with the readings of the weighing sensor in the metering tank.

[0016] The beneficial effects of this invention are: This invention provides a fully automatic calibration control method and system for metering tank scales, constructing a complete closed-loop control system that significantly improves the accuracy, efficiency, and automation of calibration. First, step S1 obtains the target load mass value and calculates the target pressure value, providing a precise benchmark for calibration and ensuring the scientific nature and repeatability of the loading process, avoiding the arbitrariness of relying on manual estimation in traditional methods. Step S2 utilizes a hydraulic control module to drive the hydraulic cylinder to extend and retract, applying a load to a standard sensor while simultaneously acquiring the readings from the metering tank weighing sensor, achieving synchronous physical loading and data acquisition, reducing error accumulation in intermediate stages, and making the calibration process more direct and reliable. In step S3, the application of a multi-source compensation algorithm monitors environmental parameters such as temperature, hydraulic oil status, and system pressure in real time, and dynamically corrects the target pressure value, effectively offsetting system deviations caused by external factors, such as cylinder deformation or hydraulic oil volume fluctuations due to temperature changes, thereby ensuring the stability and accuracy of the load output. Step S4 controls the hydraulic control module to output a precise load based on the modified control command, and compares the standard sensor reading with the metering tank reading to complete the final verification of the calibration. Step S5 repeats steps S2 to S4 to realize the automatic calibration process of lifting and lowering, and outputs the calibration results. This comprehensively covers the performance test of the metering tank scale, including linearity and repeatability evaluation, making the calibration results more accurate and traceable. It solves the technical problems of existing metering tank calibration devices lacking an automatic compensation mechanism for error sources such as temperature fluctuations, hydraulic oil leakage, and component drift. Their calibration accuracy is easily affected by environmental factors, leading to increased calibration errors. At the same time, they still rely on manual intervention, cannot achieve closed-loop control of the entire process, have long calibration time, and are difficult to adapt to the rapid debugging of metering tanks with different ranges, resulting in low calibration accuracy and insufficient automation. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the fully automatic calibration and control method for the metering tank scale in this invention. Detailed Implementation

[0018] This invention provides a fully automatic calibration control method and system for metering tank scales, which will be described in detail below through embodiments.

[0019] It should be noted that the fully automatic calibration control method and system for metering tank scales in this invention is used to compensate and control a metering tank calibration device disclosed in the patent application document with application number CN202321127487.0. Its hardware structure and application scenario are also the same, so they will not be described in detail.

[0020] Example 1 See Figure 1 The diagram illustrates the fully automatic calibration control method for metering tank scales according to the present invention, including: S1: Obtain the target load mass value, determine multiple calibration points based on the range of the metering tank, and calculate the target pressure value that the calibration system needs to output based on the calibration points; S2: The hydraulic cylinder is extended and retracted by the hydraulic control module to apply a load corresponding to the target pressure value to the standard sensor, while the reading of the weighing sensor of the metering tank is collected at the same time. S3: Real-time monitoring of environmental parameters, including temperature, hydraulic oil status and system pressure, based on and applying a multi-source compensation algorithm to correct the target pressure value and generate corrected control commands; S4: Based on the corrected control command, control the hydraulic control module to output a precise load, and compare the reading of the standard sensor of the calibration system with the reading of the weighing sensor of the metering tank to complete the calibration; S5: Repeat steps S2 to S4 to implement the automatic calibration process for lift and descent, and output the calibration results.

[0021] In this embodiment, a complete closed-loop control system is constructed, significantly improving the accuracy, efficiency, and automation of calibration. First, step S1 obtains the target load mass value and calculates the target pressure value, providing a precise benchmark for calibration and ensuring the scientific nature and repeatability of the loading process, avoiding the arbitrariness of relying on manual estimation in traditional methods. Step S2 uses the hydraulic control module to drive the hydraulic cylinder to extend and retract, applying a load to the standard sensor while simultaneously acquiring the reading from the weighing sensor of the metering tank. This achieves synchronous physical loading and data acquisition, reducing error accumulation in intermediate links and making the calibration process more direct and reliable. In step S3, the application of a multi-source compensation algorithm monitors environmental parameters such as temperature, hydraulic oil status, and system pressure in real time, and dynamically corrects the target pressure value, effectively offsetting system deviations caused by external factors, such as cylinder deformation or hydraulic oil volume changes due to temperature variations. The system eliminates fluctuations, thus ensuring the stability and accuracy of the load output. Step S4 controls the hydraulic control module to output a precise load based on the corrected control command, and compares the standard sensor readings with the metering tank readings to complete the final verification of the calibration. Step S5 repeats steps S2 to S4 to realize the automatic calibration process of lifting and lowering, and outputs the calibration results. This comprehensively covers the performance testing of the metering tank scale, including linearity and repeatability evaluation, making the calibration results more accurate and traceable. It solves the technical problems of existing metering tank calibration devices lacking an automatic compensation mechanism for error sources such as temperature fluctuations, hydraulic oil leakage, and component drift. Their calibration accuracy is easily affected by environmental factors, leading to increased calibration errors. At the same time, they still rely on manual intervention, cannot achieve closed-loop control of the entire process, have long calibration times, and are difficult to adapt to the rapid debugging of metering tanks with different ranges, resulting in low calibration accuracy and insufficient automation.

[0022] Optionally, in step S1 of the present invention, the target pressure value is obtained as follows: The target load mass corresponding to the calibration point. It is the acceleration due to gravity. The target pressure value needs to be output to calibrate the system.

[0023] It should be noted that in this embodiment, the target load mass unit corresponding to the calibration point is kg, and the target pressure value output by the calibration system is kN.

[0024] Optionally, in step S3 of the present invention, the multi-source compensation algorithm includes at least one of cylinder temperature compensation, hydraulic oil expansion compensation, electro-hydraulic valve temperature compensation, and hydraulic oil leakage compensation. The application of the multi-source compensation algorithm is achieved through the following steps: S31: Collects real-time temperature data, including cylinder operating temperature, hydraulic oil temperature, and electro-hydraulic valve temperature; S32: Calculate the cylinder deformation compensation pressure, hydraulic oil expansion pressure deviation, and electro-hydraulic valve current correction amount based on temperature deviation; S33: Calculate the pressure loss caused by hydraulic oil leakage based on system pressure; S34: Coordinates and integrates all compensation quantities to generate corrected PID setpoint pressure and control current.

[0025] In this embodiment, steps S31 to S34 achieve integrated processing of cylinder temperature compensation, hydraulic oil expansion compensation, electro-hydraulic valve temperature compensation, and hydraulic oil leakage compensation. These compensation items cover the most common error sources in the calibration process, ensuring the stability of the system under various operating conditions. Specifically, step S31 collects real-time temperature data, including cylinder operating temperature, hydraulic oil temperature, and electro-hydraulic valve temperature. This real-time monitoring mechanism can promptly capture environmental changes, providing data support for compensation and avoiding error accumulation caused by delayed monitoring in traditional methods. Step S32 calculates cylinder deformation compensation pressure, hydraulic oil expansion pressure deviation, and electro-hydraulic valve current correction based on temperature deviation. These calculation models directly address thermal expansion and contraction effects and component drift, such as deformation caused by cylinder material expansion or changes in hydraulic oil viscosity, thereby accurately offsetting the effects of temperature. Step S33 calculates the pressure loss caused by hydraulic oil leakage. By quantifying the leakage flow, the system pressure is dynamically corrected, solving the problem of load attenuation caused by leakage during long-term operation. Step S34 integrates all compensation quantities to generate corrected PID set pressure and control current. This integration method ensures that the compensation items do not conflict with each other but work synergistically, ultimately outputting stable control commands.

[0026] Optionally, in step S32 of the present invention, the cylinder temperature compensation is achieved through the following model: Hydraulic cylinder axial deformation model: ΔL = α·L0·ΔT; Compensation pressure model: ΔF comp =K·α·L0·(T T0); Where α is the coefficient of thermal expansion of the cylinder material, L0 is the effective length of the cylinder, ΔT is the temperature deviation, K is the system stiffness coefficient, T is the real-time temperature data, T0 is the standard working temperature, and ΔT = T - T0.

[0027] It should be noted that in this embodiment, the effective length of the hydraulic cylinder is in meters (m), and the units for temperature deviation, real-time temperature data, and standard operating temperature are in degrees Celsius (°C).

[0028] In this embodiment, the cylinder axial deformation model and the compensation pressure model calculate the deformation and compensation pressure based on the material expansion coefficient and temperature deviation. This model considers the thermal expansion and contraction characteristics of the cylinder during operation and can adjust the target pressure value in real time to avoid stroke errors caused by temperature fluctuations. For example, in high-temperature environments, cylinder elongation may cause deviations in the loading force, but this model, through compensation pressure correction, ensures that the actual output of the hydraulic cylinder is consistent with the theoretical value. This compensation method of the present invention not only improves the accuracy of a single calibration but also enhances the reliability of the system under varying temperature conditions, making the calibration results unaffected by seasonal or regional temperature differences.

[0029] Meanwhile, model parameters such as the effective length of the cylinder and the system stiffness coefficient can be calibrated experimentally, ensuring the practicality and customizability of the model, which is applicable to hydraulic systems of different specifications. Overall, the compensation model of this invention provides a theoretical basis for cylinder temperature compensation, reduces systematic errors in calibration, and reflects the optimization of the invention in the details.

[0030] Optionally, in step S32 of the present invention, the cylinder temperature compensation is achieved through the following model: Hydraulic oil volume expansion: ΔV oil =γ·V0·ΔT; Pressure deviation model: ΔP oil =(γ·ΔT) / β; Where γ is the hydraulic oil volume expansion coefficient, V0 is the system closed volume, β is the hydraulic oil compressibility coefficient, and ΔT is the temperature deviation.

[0031] It should be noted that the unit of the system's sealed volume in this embodiment is m³.

[0032] In this embodiment, by using a hydraulic oil volume expansion and pressure deviation model, the compensation can calculate and correct the impact of oil expansion on pressure in real time. For example, when the hydraulic oil temperature rises, volume expansion leads to an increase in system pressure, causing load deviation. This model dynamically adjusts the PID set pressure through pressure deviation calculation to offset the expansion effect. This compensation mechanism of the present invention is particularly suitable for calibration processes that operate for extended periods, avoiding drift errors caused by cumulative changes in oil temperature. Simultaneously, model parameters such as the volume expansion coefficient and compressibility coefficient are set based on the oil type, ensuring the accuracy of the compensation and enhancing the system's adaptability under different hydraulic oil conditions.

[0033] Optionally, in step S32 of the present invention, the cylinder temperature compensation is achieved through the following model: Current correction amount: ΔI valve =K I ·ΔT valve Final control current: I control_final =I ref +ΔI valve Among them, K I ΔT is the current-temperature compensation coefficient. valve Temperature deviation of electro-hydraulic valve; I ref This is the reference control current at the standard operating temperature.

[0034] It should be noted that the unit of the reference control current at the standard operating temperature in this embodiment is amperes (A).

[0035] In this embodiment, the control current of the electro-hydraulic valve is adjusted by a current correction, ensuring the accuracy of the valve core's movement and thus maintaining the stability of flow control. Specifically, the model calculates the current correction based on the temperature deviation of the electro-hydraulic valve and ultimately generates the control current, effectively offsetting the drift of the electromagnet characteristics or the change in valve core clearance caused by temperature variations. For example, in low-temperature environments, the electro-hydraulic valve may exhibit a slow response, but the current correction can compensate in advance, ensuring that the flow output is consistent with the target. This compensation method improves the response speed and control accuracy of the hydraulic system, reduces calibration errors caused by valve performance fluctuations, and enhances the reliability of the electro-hydraulic valve under variable temperature conditions.

[0036] Optionally, in step S33 of the present invention, the cylinder temperature compensation is achieved through the following model: Leakage flow model: Q leak =C L ·P·e k·ΔT Pressure loss model: ΔP leak =Q leak / β Among them, C L denoted as the leakage coefficient, P as the real-time system pressure, k as the viscosity-temperature coefficient, β as the hydraulic oil compressibility coefficient, and ΔT as the temperature deviation.

[0037] It should be noted that the unit of real-time system pressure in this embodiment is Pa.

[0038] In this embodiment, the system pressure is dynamically corrected by calculating leakage flow and pressure loss, thus solving the load attenuation problem caused by hydraulic oil leakage. The model quantifies leakage flow and calculates pressure loss based on real-time system pressure and temperature deviations, compensating for this in control commands. This mechanism can handle leaks caused by seal wear or oil aging, ensuring stability during long-term calibration. For example, during high-pressure loading, leakage may cause a slow pressure drop; this model, through real-time correction, avoids load loss and improves system durability and calibration consistency.

[0039] Optionally, in step S4 of the present invention, the generation of the control command is based on PLC programming, and closed-loop control logic is constructed through the CodeSys environment, integrating PID algorithm to adjust the hydraulic pump and electro-hydraulic valve.

[0040] Optionally, in step S5 of the present invention, the automatic calibration process includes repeatability calibration and indication error calibration, wherein the indication error calibration is performed in the order of rise and fall.

[0041] In this embodiment, the performance of the weighing tank scale was comprehensively evaluated through a complete test sequence. The lifting and lowering sequence covered the load increase and decrease process, which could detect hysteresis error and ensure the comprehensiveness of the calibration.

[0042] It should be noted that in the various calculation models of the present invention, only the numerical correspondence is considered, and the units are not considered. Therefore, there is no need to consider the balancing of units on both sides of the equal sign.

[0043] Example 2 Secondly, the present invention also provides a fully automatic calibration control system for a metering tank scale, used to implement the fully automatic calibration control method for the metering tank scale in Embodiment 1, including a hydraulic control module, a sensor module and a software control module; The sensor module is used to drive the hydraulic cylinder to extend and retract, and to apply a load corresponding to the target pressure value to the standard sensor. The hydraulic control module is used to collect the readings of the weighing sensor of the metering tank, monitor environmental parameters in real time, including temperature, hydraulic oil status and system pressure, and transmit them to the software control module. The software control module is used to generate corrected control commands and, based on the corrected control commands, controls the hydraulic control module to output a precise load. The calibration is completed by comparing the readings of the standard sensor in the calibration system with the readings of the weighing sensor in the metering tank.

[0044] In this embodiment, a fully automatic calibration control system for a metering tank scale is provided. Through the integration of hardware and software modules, the physical carrier of the method is realized. The hydraulic control module, sensor module, and software control module work together to ensure the integration and efficiency of the calibration process. It should be noted that the implementation process and beneficial effects of the fully automatic calibration control system for a metering tank scale in this embodiment are the same as those of the fully automatic calibration control method for a metering tank scale in Embodiment 1.

[0045] Example 3 In this embodiment, the fully automatic calibration control method for the metering tank scale in Embodiment 1 is described in detail by way of example.

[0046] This example uses a weighing tank scale with a maximum capacity of 30 tons as the calibration object to illustrate the implementation process of the method described in this invention.

[0047] S1: Obtain the target load mass value and calculate the target pressure value. First, according to the national verification standard JJG539-2016 "Digital Indicating Scales", for a measuring tank scale with a capacity of 30 tons, its repeatability calibration point is determined to be 15 tons, and the indication error calibration points include 100 kg, 2500 kg, 10000 kg, 15000 kg, and 30000 kg. These target load mass values ​​are then substituted into the formula... In the figure, the gravitational acceleration g is taken as 9.8 m / s², and the initial target pressure value that the hydraulic system needs to output is calculated.

[0048] For example, for a calibration point of 30,000 kg, the calculated target pressure value is 294,000 N. This step establishes a precise numerical benchmark for the entire calibration process, ensuring the accuracy and repeatability of subsequent loading.

[0049] S2: Hydraulic loading and synchronous data acquisition Based on the target pressure value calculated by S1, the control system drives the hydraulic control module to start working. The electro-hydraulic pump starts, and the high-precision electro-hydraulic valve receives the command, controlling the flow of hydraulic oil into the hydraulic cylinder, causing its extension end to push the standard sensor upward. This force is effectively transmitted to the support legs of the metering tank, thereby loading the weighing sensor of the metering tank. During this process, the standard sensor monitors and reports the actual load value in real time, and its reading is displayed through the standard sensor instrument; simultaneously, the reading of the weighing sensor of the metering tank is also synchronously collected by the weighing instrument of the metering tank.

[0050] S3: Application of Real-time Environmental Parameter Monitoring and Multi-Source Compensation Algorithms This step is the core of achieving high precision in this method. The system monitors environmental parameters in real time, including hydraulic cylinder body temperature, hydraulic oil temperature, electro-hydraulic valve body temperature, and system pipeline pressure, through temperature and pressure sensors integrated into key components. This real-time data is sent to the software control module to activate the multi-source compensation algorithm defined in this invention.

[0051] Data Acquisition and Calculation: The system first acquires real-time temperature data and calculates its deviation ΔT from the standard operating temperature (e.g., 20℃). Subsequently, multiple compensation calculations are performed in parallel: Hydraulic cylinder temperature compensation: Based on the axial deformation model and compensation pressure model of the hydraulic cylinder in Example 1, and considering the linear expansion coefficient α, effective length L0, and temperature deviation ΔT of the hydraulic cylinder material, the axial deformation compensation pressure ΔF caused by thermal expansion and contraction is calculated. comp .

[0052] Hydraulic oil expansion compensation: Based on the hydraulic oil volume expansion amount and pressure deviation model in Embodiment 1, according to the volume expansion coefficient γ of the hydraulic oil, the closed volume V0 of the system, and the temperature deviation ΔT, calculate the pressure deviation ΔP caused by the change in the volume of the oil oil .

[0053] Electro-hydraulic valve temperature compensation: Based on the current correction amount model and the final control current model in Embodiment 1, according to the temperature compensation coefficient K of the electro-hydraulic valve I and ΔT, calculate the control current correction amount ΔI required to maintain the target flow rate valve .

[0054] Hydraulic oil leakage compensation: Based on the leakage flow rate model and pressure loss model in Embodiment 1, according to the real-time pressure P of the system, the characteristic parameters of the hydraulic oil, and the temperature deviation ΔT, calculate the pressure loss ΔP caused by system leakage leak .

[0055] Collaborative integration and instruction generation: The software control module collaboratively integrates all the above compensation amounts. Specifically, the complete correction of the final PID control is: … .

[0056] This process is implemented through the control logic based on PLC and CodeSys environment described in Embodiment 1, forming a precise closed-loop control.

[0057] S4: Precise load output and calibration comparison The hydraulic control module receives the corrected control instruction generated in S3. The high-precision electro-hydraulic valve precisely adjusts the opening according to the corrected current, and the hydraulic pump outputs the flow rate as required, so that the hydraulic cylinder outputs a precise load that highly matches the target load mass value. At this time, the standard sensor displays the traceable "standard value" after multi-source compensation. The system automatically compares this standard value with the "measured value" displayed by the weighing sensor of the metering tank. If the difference between the two is within the error range allowed by the regulation (for example, for the 15000 kg point, the allowable error is ±5 kg), it is determined that the calibration of this point is qualified; otherwise, the deviation is recorded. This comparison process is fully automated, eliminating the human reading error.

[0058] S5: Execution of the full-automatic calibration process and result output The system automatically repeats steps S2 to S4 according to a preset program to complete the entire calibration process. First, repeatability calibration is performed: the 15-ton calibration point is repeatedly loaded and unloaded five times, and the comparison results are recorded each time. Then, indication error calibration is performed: loading, stabilizing, comparing, and recording point by point in the ascending sequence of 100kg → 2500kg → 10000kg → 15000kg → 30000kg; immediately afterward, without interruption, unloading, comparing, and recording point by point in the descending sequence of 15000kg → 10000kg → 2500kg → 100kg. The entire ascending and descending sequence generates a total of 9 sets of calibration data. After the entire process is completed, the system automatically generates a calibration report containing all calibration point data, error analysis, and pass / fail conclusions, which is stored in the host computer's portable control box and can be printed. Thus, a complete fully automated calibration process is completed.

Claims

1. A fully automatic calibration control method for a metering tank scale, characterized in that, include: S1: Obtain the target load mass value, determine multiple calibration points based on the range of the metering tank, and calculate the target pressure value that the calibration system needs to output based on the calibration points; S2: The hydraulic cylinder is extended and retracted by the hydraulic control module to apply a load corresponding to the target pressure value to the standard sensor, while the reading of the weighing sensor of the metering tank is collected at the same time. S3: Real-time monitoring of environmental parameters, including temperature, hydraulic oil status and system pressure, based on and applying a multi-source compensation algorithm to correct the target pressure value and generate corrected control commands; S4: Based on the corrected control command, control the hydraulic control module to output a precise load, and compare the reading of the standard sensor of the calibration system with the reading of the weighing sensor of the metering tank to complete the calibration; S5: Repeat steps S2 to S4 to implement the automatic calibration process for lift and descent, and output the calibration results.

2. The fully automatic calibration control method for metering tank scales according to claim 1, characterized in that, In step S1, the target pressure value is obtained as follows: The target load mass corresponding to the calibration point. It is the acceleration due to gravity. The target pressure value needs to be output to calibrate the system.

3. The fully automatic calibration control method for metering tank scales according to claim 2, characterized in that, In step S3, the multi-source compensation algorithm includes at least one of cylinder temperature compensation, hydraulic oil expansion compensation, electro-hydraulic valve temperature compensation, and hydraulic oil leakage compensation. The application of the multi-source compensation algorithm is achieved through the following steps: S31: Collects real-time temperature data, including cylinder operating temperature, hydraulic oil temperature, and electro-hydraulic valve temperature; S32: Calculate the cylinder deformation compensation pressure, hydraulic oil expansion pressure deviation, and electro-hydraulic valve current correction amount based on temperature deviation; S33: Calculate the pressure loss caused by hydraulic oil leakage based on system pressure; S34: Coordinates and integrates all compensation quantities to generate corrected PID setpoint pressure and control current.

4. The fully automatic calibration control method for metering tank scales according to claim 3, characterized in that, In step S32, the cylinder temperature compensation is achieved through the following model: Hydraulic cylinder axial deformation model: ΔL = α·L0·ΔT; Compensation pressure model: ΔF comp =K·α·L0·(T T0); Where α is the coefficient of thermal expansion of the cylinder material, L0 is the effective length of the cylinder, ΔT is the temperature deviation, K is the system stiffness coefficient, T is the real-time temperature data, T0 is the standard working temperature, and ΔT = T - T0.

5. The fully automatic calibration control method for metering tank scales according to claim 3, characterized in that, In step S32, the cylinder temperature compensation is achieved through the following model: Hydraulic oil volume expansion: ΔV oil =γ·V0·ΔT; Pressure deviation model: ΔP oil =(γ·ΔT) / β; Where γ is the hydraulic oil volume expansion coefficient, V0 is the system closed volume, β is the hydraulic oil compressibility coefficient, and ΔT is the temperature deviation.

6. The fully automatic calibration control method for metering tank scales according to claim 3, characterized in that, In step S32, the cylinder temperature compensation is achieved through the following model: Current correction amount: ΔI valve =K I ·ΔT valve Final control current: I control_final =I ref +ΔI valve Among them, K I ΔT is the current-temperature compensation coefficient. valve Temperature deviation of electro-hydraulic valve; I ref This is the reference control current at the standard operating temperature.

7. The fully automatic calibration control method for metering tank scales according to claim 3, characterized in that, In step S33, the cylinder temperature compensation is achieved through the following model: Leakage flow model: Q leak =C L ·P·e k·ΔT Pressure loss model: ΔP leak =Q leak / β Among them, C L denoted as the leakage coefficient, P as the real-time system pressure, k as the viscosity-temperature coefficient, β as the hydraulic oil compressibility coefficient, and ΔT as the temperature deviation.

8. The fully automatic calibration control method for metering tank scales according to claim 1, characterized in that, In step S4, the generation of the control instructions is based on PLC programming. Closed-loop control logic is constructed through the CodeSys environment, and PID algorithm is integrated to adjust the hydraulic pump and electro-hydraulic valve.

9. The fully automatic calibration control method for metering tank scales according to claim 1, characterized in that, In step S5, the automatic calibration process includes repeatability calibration and indication error calibration, wherein the indication error calibration is performed in the order of rise and fall.

10. A fully automatic calibration control system for a measuring tank scale, used to implement the fully automatic calibration control method for a measuring tank scale as described in any one of claims 1 to 9, characterized in that, Includes a hydraulic control module, a sensor module, and a software control module; The sensor module is used to drive the hydraulic cylinder to extend and retract, and to apply a load corresponding to the target pressure value to the standard sensor. The hydraulic control module is used to collect the readings of the weighing sensor of the metering tank, monitor environmental parameters in real time, including temperature, hydraulic oil status and system pressure, and transmit them to the software control module. The software control module is used to generate corrected control commands and, based on the corrected control commands, controls the hydraulic control module to output a precise load. The calibration is completed by comparing the readings of the standard sensor in the calibration system with the readings of the weighing sensor in the metering tank.

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