A metro segment pipeline concrete pouring precision metering control system and method

Abstract

The application discloses a subway segment flow line concrete pouring precision metering control system, which comprises an electric lifting and weighing mechanism, a photoelectric limit detection mechanism, an STM32 intelligent control module and a PLC linkage communication module; the electric lifting and weighing mechanism comprises multiple electric jacks arranged symmetrically, a weighing sensor is arranged at the top of each electric jack, and the weighing sensor is used for bearing and metering the weight of a steel mold. Through the layered signal linkage logic embedded in the inherent process of the flow line, the application realizes forced checking of the pouring amount, prevents the circulation of unqualified products from the process, and greatly reduces the later scrapping and rework costs.

Description

Technical Field

[0001] This invention belongs to the technical field of automated production equipment for subway tunnel segments, and particularly relates to a precise metering control system and method for concrete pouring in subway segment production lines. Background Technology

[0002] Subway tunnel segments are the core load-bearing precast components of subway tunnel engineering. The strength, density, and dimensional stability of these components directly determine the overall construction quality and service life of the tunnel. Currently, subway tunnel segments in China are generally produced using a fully automated production line casting process. The production process is highly standardized and automated, enabling integrated operations such as automatic transfer of steel molds, automatic concrete pouring, vibration, curing, and demolding.

[0003] However, existing automated production lines have a core technological flaw: after concrete is poured into the steel mold, the concrete inside the mold is prone to defects such as air bubbles, voids, and looseness due to the influence of pouring flow rate, uniformity of material distribution, and vibration and air release effects. The existing production process lacks a real-time accurate metering and verification process, and only relies on fixed pouring time and fixed output to control the amount of concrete poured, which cannot adapt to the actual filling needs of each set of steel molds.

[0004] The specific problems manifest in three aspects: 1. Uncontrollable deviation in pouring volume: Due to the space occupied by internal air bubbles and voids, the actual net weight of concrete filled into each set of steel molds is inconsistent under the same pouring parameters. Some molds are not filled with enough concrete, and the effective cross-sectional thickness and density of the tunnel segments do not meet the standards; 2. Poor consistency in product quality: The weight deviation of the tunnel segment concrete produced by different batches and different molds is large, resulting in individual differences in the compressive strength, impermeability, and structural stability of the tunnel segments. The quality of batch products is uneven and does not meet the high-precision standardized construction requirements of subway projects; 3. Lack of intermediate verification in the production line: The existing production line is fully autonomously controlled by PLC. After the empty mold is in place, pouring and vibration operations are carried out directly. After the process is completed, the PLC directly issues a departure signal to transfer to the next workstation. There is no weight verification step after pouring. Unqualified components directly flow into subsequent processes, resulting in high rework and scrap costs.

[0005] Meanwhile, traditional lifting mechanisms rely solely on timing control for start and stop, lacking physical limit protection, which can easily lead to problems such as jack over-extension and equipment damage; conventional weighing methods do not consider the load change pattern to determine the suspended state of the mold, which can easily lead to problems such as improper weighing sampling timing and data distortion; and most human-machine interaction terminals use a single programming language, resulting in shortcomings in operating efficiency, stability, and functional expandability in industrial scenarios.

[0006] In summary, the lack of real-time and accurate detection of concrete pouring weight, lifting overtravel prevention limit, dynamic load identification, process signal interception and forwarding, high-performance host computer interaction, and full-process closed-loop control technology in existing metro segment automated production lines are key technical pain points that restrict the stability of segment mass production quality. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art. By embedding layered signal linkage logic into the inherent process of the production line, this invention achieves mandatory verification of the pouring volume, thereby eliminating the flow of unqualified products from the process and significantly reducing the cost of scrapping and rework in the later stage.

[0008] To achieve the above-mentioned objectives, the technical solution provided by this invention patent is as follows: A precise metering and control system for concrete pouring in a subway segment production line, the system includes an electric lifting and weighing mechanism, a photoelectric limit detection mechanism, an STM32 intelligent control module and a PLC linkage and communication module; The electric lifting and weighing mechanism includes multiple symmetrically arranged electric jacks, each of which is equipped with a weighing sensor on its top. The weighing sensor is used to support and measure the weight of the steel mold. The photoelectric limit detection mechanism includes an upper limit photoelectric switch and a lower limit photoelectric switch installed at each electric jack. The upper limit photoelectric switch is used to prevent the jack from lifting beyond its travel range, and the lower limit photoelectric switch is used to detect the jack's return and reset state. The STM32 intelligent control module is electrically connected to the electric jack, the weighing sensor, the photoelectric limit detection mechanism, and the PLC linkage communication module, respectively. The PLC linkage communication module is used to realize bidirectional signal interaction with the production line PLC control system. The bidirectional signal interaction includes at least: receiving the mold arrival signal sent by the PLC; sending a signal to the PLC to start the casting process after the empty mold weighing is completed; intercepting the original station release signal output by the PLC after the casting process is completed to trigger secondary weighing; and selectively forwarding the final release signal to the PLC or blocking the release signal according to the secondary weighing result. The STM32 intelligent control module has a built-in dynamic weighing determination unit and a PLC signal processing unit. The dynamic weighing determination unit is used to continuously collect weighing data during the lifting process of the jack. When the weighing data changes from continuous rise to stable and unchanged, it determines that the steel mold is completely suspended and locks the current weight as a valid sample value. The PLC signal processing unit is used to receive, send, intercept and forward PLC signals, and decide whether to forward the final release signal to the PLC based on whether the secondary weighing is qualified.

[0009] Furthermore, the STM32 intelligent control module also has a built-in AD conversion unit, a synchronization control unit, a position protection unit, a weight calculation unit, and a threshold determination unit; The AD conversion unit is used to convert the analog signal output by the weighing sensor into a digital weight signal; the synchronization control unit is used to independently control the start, stop, and lifting speed of multiple electric jacks to ensure their synchronous operation; the position protection unit is used to monitor the upper limit photoelectric switch signal in real time, and immediately force the jack lifting to stop upon triggering, while simultaneously collecting the lower limit photoelectric switch signal to confirm the jack's reset status; the weight calculation unit is used to calculate the actual net weight of the poured concrete by the difference between the empty mold weight and the total weight after pouring; the threshold judgment unit is used to compare the actual net weight of the poured concrete with a preset standard threshold and output the judgment result of whether the pouring is qualified, insufficient, or excessive.

[0010] Furthermore, the system also includes a wireless 485 human-machine interaction module, which includes an industrial touch screen all-in-one machine and a wireless communication unit. The industrial touch screen all-in-one machine acts as a host computer and establishes data interaction with the STM32 intelligent control module through wireless frequency band and 485 communication protocol. The host computer program on the industrial touch screen all-in-one machine is used to display the weighing sensor values, empty mold weight, total weight after pouring, net weight of concrete pouring, jack position status, and PLC signal interaction status in real time.

[0011] A precise metering method for concrete pouring in a subway segment production line, applied to the aforementioned control system, specifically includes the following steps: S1. After the steel mold is transferred to the casting station and positioned, the production line PLC outputs a mold arrival signal. The STM32 intelligent control module receives the signal and starts the empty mold weighing process. S2, STM32 drives multiple electric jacks to lift synchronously. During the lifting process, the upper limit photoelectric switch monitors the stroke in real time to prevent overtravel. At the same time, STM32 continuously collects weighing sensor data. When the weighing data changes from an upward trend to a stable and unchanged state, it is determined that the steel mold has completely left the production line track, and the current weight is collected and stored as the weight of the empty mold. S3. After the empty mold is weighed, the STM32 controls the jack to descend. After the lower limit photoelectric switch is triggered and confirmed to reset, the STM32 sends a start signal to the PLC, and the production line performs concrete pouring and vibration operations. S4. After the pouring and vibration process is completed, the STM32 intercepts the original station release signal output by the PLC and starts the secondary weighing process according to the intercepted signal; the STM32 drives the jack to lift again, and collects the total weight of the mold and concrete after the weighing data stabilizes. S5, STM32 calculates the actual net weight of the poured concrete through difference calculation, and compares the net weight with the preset standard threshold to determine whether the pouring quality is qualified. S6. After the second weighing judgment is completed, the STM32 controls the jack to descend and reset. If the casting weight judgment is qualified, the STM32 forwards the final release signal to the PLC, allowing the mold to flow to the next station. If the judgment is unqualified or an equipment abnormality occurs, the STM32 blocks the release signal and locks the production line.

[0012] Furthermore, in S2, when the weighing data changes from an upward trend to a stable state, the specific implementation of determining that the steel mold is completely detached from the production line track is as follows: the dynamic weighing determination unit monitors the data of four weighing sensors in real time. When the fluctuation value of all data is less than the preset threshold within a preset time, the weight data is determined to have reached a stable state, that is, the steel mold is confirmed to be completely suspended.

[0013] Furthermore, the specific process of the STM32 in S4 intercepting the original station release signal output by the PLC and initiating the secondary weighing process based on the intercepted signal is as follows: The STM32's PLC signal processing unit listens to the PLC's output port. When it detects the rising or falling edge of the release signal issued by the PLC, it intercepts the signal inside the STM32 and prevents it from being directly transmitted to the pipeline drive mechanism. At the same time, it uses the intercepted signal as a trigger command to start the secondary weighing process. Before the secondary weighing is completed, the release signal is held inside the STM32, and the pipeline is in a waiting state.

[0014] Furthermore, the STM32 dynamically adjusts the operating parameters of multiple electric jacks to ensure their synchronization during lifting and lowering; it relies on an upper limit photoelectric switch to achieve physical hardware protection against lifting overtravel, and a lower limit photoelectric switch to ensure the timing safety of process switching; if the secondary weighing fails, the STM32 uploads the failure data to the host computer via wireless 485 communication and triggers an audible and visual warning. Only after manual intervention and successful re-inspection is the STM32 allowed to forward the final release signal to the PLC.

[0015] Based on the above technical solution, the present invention patent, a precise metering control system and method for concrete pouring in subway segment production lines, has achieved the following technical effects through practical application: 1. This invention achieves mandatory verification of the pouring volume by embedding layered signal linkage logic into the inherent process of the production line, thereby eliminating the flow of unqualified products from the process and significantly reducing the cost of scrapping and rework in the later stage.

[0016] 2. This invention intelligently determines the suspended state of the mold by tracking the changes in weighing data in real time during the lifting process, ensuring accurate timing of weighing sampling, effectively avoiding measurement errors caused by mechanical contact, and improving the authenticity and reliability of the data.

[0017] 3. This invention utilizes an upper limit photoelectric switch to achieve physical hardware protection against lifting overtravel, eliminating the risk of equipment damage; combined with a lower limit switch, it ensures strict process timing and significantly extends the service life of the equipment.

[0018] 4. This invention uses a double weighing difference measurement method of "empty mold + after pouring" to accurately verify the amount of concrete poured, effectively avoiding quality defects in the segments caused by voids, looseness, etc., and significantly improving the pass rate and consistency of batch products. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall installation structure of a precision metering and control system for concrete pouring in a subway segment production line according to the present invention.

[0020] Figure 2 This invention relates to a flowchart of the assembly line process and signal interaction in a precision metering control system for concrete pouring in a subway segment assembly line.

[0021] Figure 3 This is a flowchart of a precise metering and control system for concrete pouring in a subway segment production line according to the present invention.

[0022] Figure 4 This is a block diagram of the electrical control principle in a precision metering and control system for concrete pouring in a subway segment production line according to the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and effects of this invention clearer, specific examples are provided below. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of this invention.

[0024] Example 1, such as Figure 1 As shown, a precise metering and control system for concrete pouring in a subway segment production line is disclosed. The system includes an electric lifting and weighing mechanism, a photoelectric limit detection mechanism, an STM32 intelligent control module, and a PLC linkage communication module. The electric lifting and weighing mechanism includes multiple symmetrically arranged electric jacks 2, and each electric jack 2 is equipped with a weighing sensor 3 on its top. The weighing sensor 3 is used to support and measure the weight of the steel mold. The photoelectric limit detection mechanism includes an upper limit photoelectric switch and a lower limit photoelectric switch installed at each electric jack 2. The upper limit photoelectric switch is used to prevent the jack 2 from lifting beyond its travel range, and the lower limit photoelectric switch is used to detect the jack 2's return to its reset state. The STM32 intelligent control module is electrically connected to the electric jack 2, the weighing sensor 3, the photoelectric limit detection mechanism and the PLC linkage communication module respectively. The PLC linkage communication module is used to realize bidirectional signal interaction with the production line PLC control system. The bidirectional signal interaction includes at least: receiving the mold arrival signal sent by the PLC; sending a signal to the PLC to start the casting process after the empty mold weighing is completed; intercepting the original station release signal output by the PLC after the casting process is completed to trigger secondary weighing; and selectively forwarding the final release signal to the PLC or blocking the release signal according to the secondary weighing result. The STM32 intelligent control module has a built-in dynamic weighing determination unit and a PLC signal processing unit. The dynamic weighing determination unit is used to continuously collect weighing data during the lifting process of jack 2. When the weighing data changes from continuous rise to stable and unchanged, it determines that the steel mold is completely suspended and locks the current weight as a valid sample value. The PLC signal processing unit is used to receive, send, intercept and forward PLC signals, and decide whether to forward the final release signal to the PLC based on whether the secondary weighing is qualified.

[0025] The STM32 intelligent control module also has a built-in AD conversion unit, synchronization control unit, position protection unit, weight calculation unit and threshold determination unit. The AD conversion unit is used to convert the analog signal output by the weighing sensor 3 into a digital weight signal; the synchronization control unit is used to independently control the start, stop and lifting speed of multiple electric jacks 2 to ensure their synchronous operation; the position protection unit is used to monitor the upper limit photoelectric switch signal in real time, and immediately force the lifting of the jack 2 to stop after triggering, while collecting the lower limit photoelectric switch signal to confirm the reset state of the jack 2; the weight calculation unit is used to calculate the actual net weight of the poured concrete by the difference between the empty mold weight and the total weight after pouring; the threshold judgment unit is used to compare the actual net weight of the poured concrete with a preset standard threshold and output the judgment result of whether the pouring is qualified, insufficient or excessive.

[0026] The system also includes a wireless 485 human-machine interaction module, which includes an industrial touch screen all-in-one machine and a wireless communication unit. The industrial touch screen all-in-one machine acts as a host computer and establishes data interaction with the STM32 intelligent control module through wireless frequency band and 485 communication protocol. The host computer program on the industrial touch screen all-in-one machine is used to display the values ​​of the weighing sensor 3, the weight of the empty mold, the total weight after pouring, the net weight of the concrete pouring, the position status of the jack 2, and the PLC signal interaction status in real time.

[0027] A precise metering method for concrete pouring in a subway segment production line, applied to the aforementioned control system, specifically includes the following steps: S1, after steel mold 1 is transferred to the casting station and positioned, the production line PLC outputs a mold arrival signal, and the STM32 intelligent control module receives the signal and starts the empty mold weighing process. S2, STM32 drives multiple electric jacks 2 to lift synchronously. During the lifting process, the upper limit photoelectric switch monitors the stroke in real time to prevent overtravel. At the same time, STM32 continuously collects data from the weighing sensor 3. When the weighing data changes from an upward trend to a stable and unchanged state, it is determined that the steel mold 1 has completely left the production line track, and the current weight is collected and stored as the weight of the empty mold. S3, after the empty mold is weighed, the STM32 controls the jack 2 to descend. After the lower limit photoelectric switch is triggered and confirmed to reset, the STM32 sends a start signal to the PLC, and the production line performs concrete pouring and vibration operations. S4. After the pouring and vibration process is completed, the STM32 intercepts the original station release signal output by the PLC and starts the secondary weighing process according to the intercepted signal; the STM32 drives the jack 2 to lift again, and collects the total weight of the mold and concrete after the weighing data stabilizes. S5, STM32 calculates the actual net weight of the poured concrete through difference calculation, and compares the net weight with the preset standard threshold to determine whether the pouring quality is qualified. S6. After the second weighing judgment is completed, the STM32 controls the jack 2 to descend and reset. If the casting weight judgment is qualified, the STM32 forwards the final release signal to the PLC, allowing the mold to flow to the next station. If the judgment is unqualified or an equipment abnormality occurs, the STM32 blocks the release signal and locks the production line.

[0028] In S2, when the weighing data changes from an upward trend to a stable state, the specific implementation of determining that the steel mold 1 is completely removed from the production line track is as follows: the dynamic weighing determination unit monitors the data of the four weighing sensors 3 in real time. When the fluctuation value of the data of all channels is less than the preset threshold within a preset time, it is determined that the weight data has reached a stable state, that is, it is confirmed that the steel mold 1 is completely suspended.

[0029] The specific process of the STM32 in S4 intercepting the original station release signal output by the PLC and initiating the secondary weighing process based on the intercepted signal is as follows: The STM32's PLC signal processing unit listens to the PLC's output port. When it detects the rising or falling edge of the release signal issued by the PLC, it intercepts the signal inside the STM32 and prevents it from being directly transmitted to the pipeline drive mechanism. At the same time, it uses the intercepted signal as a trigger command to start the secondary weighing process. Before the secondary weighing is completed, the release signal is held inside the STM32, and the pipeline is in a waiting state.

[0030] The STM32 dynamically adjusts the operating parameters of multiple electric jacks 2 to ensure their synchronization during lifting and lowering. It relies on upper limit photoelectric switches to achieve physical hardware protection against lifting overtravel and lower limit photoelectric switches to ensure the timing safety of process switching. If the secondary weighing fails, the STM32 uploads the failure data to the host computer via wireless 485 communication and triggers an audible and visual alarm. Only after manual intervention and successful re-inspection can the STM32 forward the final release signal to the PLC.

[0031] Example 2, as Figure 1-2 As shown, this invention discloses a precise metering and control system for concrete pouring in a subway segment production line. It integrates six core units: an electric lifting and weighing mechanism, a photoelectric limit detection mechanism, a signal acquisition and conversion module, an STM32 intelligent control module, a wireless 485 human-machine interaction module, and a PLC linkage communication module. It is fully compatible with the existing automated subway segment production line layout, without the need for major modifications to the original production line, and can be quickly installed and adapted.

[0032] The system's core operating logic is as follows: After the steel mold moves along the production line to the pouring station and is positioned, the production line PLC outputs a trigger signal. The STM32 control system receives the signal and initiates the metering process. Four electric jacks are simultaneously lifted, with upper limit photoelectric switches monitoring the entire process to prevent over-lifting. During the lifting process, the STM32 collects weighing data in real time. When the data changes from rising to stable, it is determined that the steel mold is completely suspended, completing the empty mold weight sampling. After the empty mold is weighed, the STM32 sends a start signal to the PLC, and the production line executes the concrete pouring and vibration processes. After the pouring and vibration operations are completed, the STM32 intercepts the original station release signal output by the PLC, triggering a secondary weighing process. The mold is lifted again, and the total weight is collected, calculating the net weight of the poured concrete and determining whether it meets the standard. The touch screen all-in-one machine acts as the host computer, and its supporting operating program is developed in C++. It interacts with the STM32 via a 433MHz wireless band and the RS485 communication protocol, displaying various parameters and equipment status in real time. If the weight of the poured concrete meets the standard, the STM32 forwards the final release signal to the PLC, and the production line continues to operate normally; if the weight is abnormal or the equipment malfunctions, the production line is locked and an early warning is triggered, thus achieving closed-loop control of the entire process.

[0033] (II) Core System Composition and Detailed Structure 1. Electric lifting and weighing actuator Four electric jacks are symmetrically installed at the four corners of the bottom of the pouring station on the production line. Each electric jack has a high-precision seat-type weighing sensor fixedly integrated on its top. The four sets of sensors are symmetrically distributed in a rectangle and correspond precisely to the support points at the bottom of the steel mold to ensure uniform force and accurate measurement.

[0034] The electric jack has a synchronous drive structure, which is responsible for the smooth lifting and lowering of the steel mold. The lifting height meets the requirements of weighing and suspended measurement, avoids the force interference of rollers and tracks on the production line, ensures that the weight data is collected purely from the mold load, and eliminates the measurement error caused by mechanical contact.

[0035] 2. Photoelectric limit detection mechanism Each electric jack is equipped with an upper limit photoelectric switch and a lower limit photoelectric switch, and the signal output of the photoelectric switch is connected to the digital input of the STM32 chip.

[0036] Upper limit photoelectric switch: Its main function is to prevent overtravel protection during lifting. When the jack rises to the limit position, it is triggered immediately. After receiving the signal, the STM32 will forcibly stop the lifting action to avoid the mechanism from jamming, deforming, or being damaged. Lower limit photoelectric switch: Used to detect the jack's descent into position. After the jack returns to its initial position and the mold is completely back on the production line track, the photoelectric switch is triggered and sends a reset signal to the STM32 as a condition for process switching.

[0037] 3. STM32 intelligent main control module As the core control hub of this system, it undertakes all data processing, equipment control, logic operations, and signal interaction functions. Its core functions are as follows: Synchronous lifting and overtravel protection control: Individually control the start / stop, lifting speed, and lifting stroke of four electric jacks; read the upper limit photoelectric switch signal in real time, and immediately cut off the lifting output once triggered to achieve overtravel protection; dynamically adjust the output power of each jack to ensure that the four lifting mechanisms operate synchronously and avoid tilting or shifting of the steel mold.

[0038] Dynamic weighing monitoring and sampling judgment: During the lifting process of the jack, the STM32 continuously collects the analog signals of four weighing sensors, and tracks the changes in weight data in real time after AD conversion; when the mold is not off the track, the weighing value is close to 0, and the value continues to rise as the mold is gradually lifted. When the weight data remains stable and no longer increases, it is determined that the mold is completely suspended, and the current weight is immediately locked as the valid sampling value.

[0039] Signal AD conversion processing: Receives the analog voltage signal output from the four-position weighing sensor, converts the analog signal into a digital weight signal through the built-in AD conversion unit, filters out fluctuation noise and mechanical vibration interference, and outputs an accurate and stable weight value.

[0040] Intelligent calculation of pouring volume: Automatically stores empty mold weight data, collects the total weight of the mold after pouring and vibration, and accurately calculates the actual net weight of the poured concrete through the difference algorithm.

[0041] Threshold determination logic: The built-in standard concrete pouring weight upper and lower limit thresholds for tunnel segments are automatically compared with the measured net weight and the standard threshold to determine three working conditions: qualified pouring, insufficient pouring, and excessive pouring.

[0042] Wireless 485 communication processing: An external 433MHz wireless communication module is connected to establish wireless data interaction with the host computer touch screen all-in-one machine based on the 485 communication protocol, upload weight data, equipment status, and fault information, and receive parameter setting and calibration instructions issued by the host computer.

[0043] PLC bidirectional signal interaction and interception forwarding: Receives the mold arrival signal sent by the PLC; after the empty mold is weighed, it sends a signal to the PLC to start the pouring and vibration process; after the pouring and vibration are completed, it intercepts the original station release signal of the PLC and starts the secondary weighing; after the secondary weighing is qualified, it forwards the final release signal to the PLC; if it is unqualified or the equipment is abnormal, it blocks the release signal and locks the production line.

[0044] 4. Wireless 485 Human-Computer Interaction Display Module This module uses an industrial touch screen all-in-one machine as the host computer. The accompanying operating program is developed in C++, offering advantages such as high execution efficiency, good real-time performance, strong compatibility with industrial environments, and easy functional expansion. The hardware is equipped with a 433MHz wireless communication module, using the 433MHz wireless band and the 485 communication protocol to achieve long-distance wireless data transmission with the lower-level STM32 microcontroller, eliminating the constraints of wired cabling on-site. Real-time synchronous display of independent values ​​of four weighing sensors, weight change status, empty mold weight, total weight after pouring, net weight of concrete pouring, lifting position status of jack, photoelectric switch signal status, and PLC signal interaction status. It dynamically displays the jack's operating status, equipment fault codes, metering progress, and production station status; it supports manual issuance of instructions via wireless communication, preset pouring weight standard thresholds, calibrate sensor parameters, set limit parameters, configure weight stability judgment conditions, view historical metering data, and export production reports. Automatic pop-up warnings and audio-visual prompts will be issued for abnormal working conditions (unqualified pouring volume, sensor failure, jack asynchrony, over-travel, and incomplete lifting).

[0045] 5. PLC linkage communication module Establish a bidirectional signal interface between the STM32 control system and the native PLC control system of the subway segment production line to achieve signal reception, transmission, interception, and forwarding: First input: Captures the mold positioning completion signal sent by the production line PLC, which serves as the start condition for the first round of metering process in this system; First output: After the empty mold weighing is completed and the jack falls back to the lower limit, a pouring and vibration start signal is sent to the PLC to trigger the production line to perform concrete pouring and vibration operations. Second input: After the pouring and vibration process is completed, the original station release signal output by the PLC is intercepted as the start condition for the secondary weighing process; Second output: If the secondary weighing test is successful and the jack falls back to the lower limit, a final station release signal is sent to the PLC; if the weighing fails or the equipment malfunctions, the release signal is blocked and the production line is locked.

[0046] (III) Complete production measurement and control methods This invention also provides a precise measurement production method adapted to the above system, comprising the following steps: Equipment standby calibration: After the production line is powered on, the STM32 system automatically completes sensor zero-point calibration, jack synchronization self-test, and photoelectric limit signal self-test; the touch screen all-in-one computer (C++ program) starts running and sends the standard threshold for concrete pouring weight and weight stability judgment parameters for the corresponding specification of pipe segment to the STM32 through 433MHz wireless 485 communication, and the system enters standby monitoring state.

[0047] Workstation positioning trigger: The steel mold automatically flows to the casting station with the production line. After precise positioning and locking, the production line PLC outputs a mold arrival signal. The STM32 receives the signal and starts the first round of measurement program.

[0048] Empty mold weighing operation 3.1 The STM32 drives four electric jacks to rise synchronously, and monitors the upper limit photoelectric switch signal in real time throughout the process. If triggered, the lifting will stop immediately and an overtravel fault will be reported. 3.2 During the lifting process, weighing data is continuously collected. The initial value is close to 0, and the weight value continues to rise as the mold is gradually lifted. 3.3 When the weighing data is stable and no longer increases, it is determined that the steel mold is completely detached from the production line track and is in a suspended state. The system locks and stores the current total weight of the empty mold.

[0049] Reset and start pouring and vibration: After the empty mold sampling is completed, the STM32 controls the jack to descend synchronously. Upon receiving the lower limit photoelectric switch signal, the mold is confirmed to be reset. Then, the STM32 sends a start signal to the PLC, and the production line automatically executes the concrete pouring and vibration process.

[0050] Intercept the release signal and start the secondary weighing: After the concrete pouring and vibration are completed, the production line PLC outputs the original station release signal; the STM32 intercepts the signal and starts the secondary weighing process.

[0051] Total weight acquisition after pouring: The STM32 drives the four jacks to rise synchronously again, and the upper limit photoelectric switch continues to perform overtravel protection; the dynamic weighing monitoring logic is repeated, and after the weighing data stabilizes and stops increasing, the total weight of the mold and concrete is acquired, and all data is uploaded to the upper computer interface developed in C++ for real-time display via 433MHz wireless 485 communication.

[0052] Data Calculation and Acceptance Judgment: STM32 automatically calculates "Total weight after pouring - weight of empty formwork = actual net weight of poured concrete" and compares it with the preset standard weight range. If the measured net weight is within the standard threshold range, the pouring is deemed qualified. If the measured net weight is lower than the lower limit, it is determined that the concrete filling is insufficient and there are voids. The actual net weight was higher than the upper limit, indicating that excessive pouring and waste of raw materials were identified.

[0053] Secondary reset and process flow 8.1 After the judgment is completed, control the jack to fall back synchronously, and receive the lower limit photoelectric switch to the position signal; 8.2 Casting weight meets the standard: STM32 forwards the final release signal to PLC, and the production line drives the mold to the next process; 8.3 Abnormal pouring weight, excessive lifting, or abnormal position signal: Block the release signal, lock the production line and trigger an audible and visual alarm, save the abnormal data, and wait for manual material replenishment or rework.

[0054] Data storage iteration: All measurement data, weight change records, equipment operation data, signal interaction status, and qualification judgment results are stored in real time and synchronized to a C++ host computer for archiving and display. It supports background traceability and data analysis, providing data support for production process optimization.

[0055] (iv) Core Innovation Points Layered process signal linkage logic: It is the first to create a phased signal interaction mode. After the empty mold is weighed, a signal is sent to start the pouring and vibration. After the pouring and vibration are completed, the PLC's original release signal is intercepted to trigger a second weighing. After the weighing is qualified, the release signal is sent again to realize the mandatory verification of the pouring volume throughout the entire process.

[0056] Intelligent determination of suspension state based on weight change: Real-time tracking of weighing data during the lifting process, and accurate determination of the moment when the mold is completely suspended based on the change pattern of the value from 0 to a stable state. Reasonable sampling timing improves weighing accuracy from the source.

[0057] Photoelectric switch graded limit protection: The upper limit photoelectric switch is dedicated to preventing the jack from lifting beyond its travel range, realizing the hard protection of the equipment; the lower limit photoelectric switch is used for reset status determination. The dual limit protection works together to ensure the safety and timing of equipment operation.

[0058] Double weighing difference measurement process: The "empty mold + double weighing difference measurement method after pouring" is adopted to accurately calculate the actual amount of concrete poured, and completely solve the problems of inaccurate pouring volume and uneven product quality caused by air bubbles and voids.

[0059] The C++ host computer is paired with a wireless communication architecture: the human-machine interaction program is developed in C++ language, which is adapted to the high real-time and high stability requirements of industrial sites; combined with 433MHz wireless + 485 communication, it eliminates the need for complex wiring on site, and the equipment is flexible in deployment, has strong anti-interference ability, and is easy to maintain.

[0060] Four-synchronous lifting precision weighing structure: Four sets of jacks are independently controlled by STM32 to operate synchronously. Combined with the four-corner symmetrical weighing layout, the measurement error caused by eccentric force and mechanical vibration is eliminated, and the measurement accuracy is adapted to the production standards of industrial prefabricated components.

[0061] Full-process closed-loop control: No need to modify the original PLC core program, quality verification is achieved through signal reception, transmission, interception and forwarding. Unqualified components cannot enter the next process, realizing integrated closed-loop management of production, inspection and interception.

[0062] The beneficial effects of this invention are: 1. Thorough process verification and closed-loop quality control: Weight detection is embedded in the inherent process nodes of the production line, and a second verification is required after pouring and vibration. This prevents the circulation of products with unqualified pouring quantities from the process and greatly reduces the cost of scrap and rework in the later stage.

[0063] 2. Significantly improved weighing sampling accuracy: Based on the changing characteristics of weighing data during the lifting process, the suspended state of the mold is determined, the sampling timing is accurate, and the weighing error caused by the mold not being completely off the track is effectively avoided, so the measurement results are true and reliable.

[0064] 3. Safe and reliable equipment operation: The upper limit photoelectric switch plays an overtravel protection role, eliminating problems such as mechanism deformation, equipment damage, and mold displacement caused by excessive lifting of the jack; the lower limit switch ensures strict process sequence and significantly extends the overall service life of the equipment.

[0065] 4. Excellent host computer performance: The host computer program is developed based on C++, with fast running speed, strong real-time performance, and high fault tolerance. It can run stably in complex industrial environments for a long time, and is also easy to iterate and develop in subsequent functions.

[0066] 5. Significantly improve the consistency of segment product quality: By accurately verifying the concrete pouring volume through double weighing, quality defects such as insufficient segment strength, substandard impermeability, and dimensional deviations caused by voids, looseness, and insufficient filling are effectively avoided, and the batch product qualification rate is significantly improved.

[0067] 6. More convenient on-site deployment: Utilizing 433MHz wireless 485 communication for human-machine interaction reduces on-site cabling, keeps the production line tidy, and makes equipment relocation, installation, and maintenance more convenient, reducing wiring and subsequent maintenance costs; Adaptable to rapid retrofitting of existing production lines: This system has a modular installation structure, only connecting to the PLC signal port, without the need to disassemble or modify the original automated production line's main equipment and control program, making installation convenient, highly compatible, low-cost, and extremely easy to implement.

[0068] Achieve intelligent and quantitative control of production: All pouring data, weight change data, equipment status, and signal interaction records can be viewed, recorded, queried, and exported in real time through a C++ host computer, providing accurate data support for production process optimization, quality traceability, and project acceptance; High degree of automation: The entire process requires no manual intervention, automatically completing the lifting, overtravel protection, dynamic weighing, signal interaction, calculation and judgment, and wireless transmission processes, and can be adapted to 24-hour continuous mass production operations on assembly lines.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A precise metering and control system for concrete pouring in a subway segment production line, characterized in that, The system includes an electric lifting and weighing mechanism, a photoelectric limit detection mechanism, an STM32 intelligent control module, and a PLC linkage communication module; The electric lifting and weighing mechanism includes multiple symmetrically arranged electric jacks, each of which is equipped with a weighing sensor on its top. The weighing sensor is used to support and measure the weight of the steel mold. The photoelectric limit detection mechanism includes an upper limit photoelectric switch and a lower limit photoelectric switch installed at each electric jack. The upper limit photoelectric switch is used to prevent the jack from lifting beyond its travel range, and the lower limit photoelectric switch is used to detect the jack's return and reset state. The STM32 intelligent control module is electrically connected to the electric jack, the weighing sensor, the photoelectric limit detection mechanism, and the PLC linkage communication module, respectively. The PLC linkage communication module is used to realize bidirectional signal interaction with the production line PLC control system. The bidirectional signal interaction includes at least: receiving the mold arrival signal sent by the PLC; sending a signal to the PLC to start the casting process after the empty mold weighing is completed; intercepting the original station release signal output by the PLC after the casting process is completed to trigger secondary weighing; and selectively forwarding the final release signal to the PLC or blocking the release signal according to the secondary weighing result. The STM32 intelligent control module has a built-in dynamic weighing determination unit and a PLC signal processing unit. The dynamic weighing determination unit is used to continuously collect weighing data during the lifting process of the jack. When the weighing data changes from continuous rise to stable and unchanged, it determines that the steel mold is completely suspended and locks the current weight as a valid sample value. The PLC signal processing unit is used to receive, send, intercept and forward PLC signals, and decide whether to forward the final release signal to the PLC based on whether the secondary weighing is qualified.

2. The precise metering and control system for concrete pouring in a subway segment production line according to claim 1, characterized in that, The STM32 intelligent control module also has a built-in AD conversion unit, synchronization control unit, position protection unit, weight calculation unit and threshold determination unit. The AD conversion unit is used to convert the analog signal output by the weighing sensor into a digital weight signal; the synchronization control unit is used to independently control the start, stop, and lifting speed of multiple electric jacks to ensure their synchronous operation; the position protection unit is used to monitor the upper limit photoelectric switch signal in real time, and immediately force the jack lifting to stop upon triggering, while simultaneously collecting the lower limit photoelectric switch signal to confirm the jack's reset status; the weight calculation unit is used to calculate the actual net weight of the poured concrete by the difference between the empty mold weight and the total weight after pouring; the threshold judgment unit is used to compare the actual net weight of the poured concrete with a preset standard threshold and output the judgment result of whether the pouring is qualified, insufficient, or excessive.

3. The precise metering and control system for concrete pouring in a subway segment assembly line according to claim 1, characterized in that, The system also includes a wireless 485 human-machine interaction module, which includes an industrial touch screen all-in-one machine and a wireless communication unit. The industrial touch screen all-in-one machine acts as a host computer and establishes data interaction with the STM32 intelligent control module through wireless frequency band and 485 communication protocol. The host computer program on the industrial touch screen all-in-one machine is used to display the weighing sensor values, empty mold weight, total weight after pouring, net weight of concrete pouring, jack position status, and PLC signal interaction status in real time.

4. A precise metering method for concrete pouring in a subway segment assembly line, applied to the control system described in any one of claims 1-3, characterized in that, The method specifically includes the following steps: S1. After the steel mold is transferred to the casting station and positioned, the production line PLC outputs a mold arrival signal. The STM32 intelligent control module receives the signal and starts the empty mold weighing process. S2, STM32 drives multiple electric jacks to lift synchronously. During the lifting process, the upper limit photoelectric switch monitors the stroke in real time to prevent overtravel. At the same time, STM32 continuously collects weighing sensor data. When the weighing data changes from an upward trend to a stable and unchanged state, it is determined that the steel mold has completely left the production line track, and the current weight is collected and stored as the weight of the empty mold. S3. After the empty mold is weighed, the STM32 controls the jack to descend. After the lower limit photoelectric switch is triggered and confirmed to reset, the STM32 sends a start signal to the PLC, and the production line performs concrete pouring and vibration operations. S4. After the pouring and vibration process is completed, the STM32 intercepts the original station release signal output by the PLC and starts the secondary weighing process according to the intercepted signal; the STM32 drives the jack to lift again, and collects the total weight of the mold and concrete after the weighing data stabilizes. S5, STM32 calculates the actual net weight of the poured concrete through difference calculation, and compares the net weight with the preset standard threshold to determine whether the pouring quality is qualified. S6. After the second weighing judgment is completed, the STM32 controls the jack to descend and reset. If the casting weight judgment is qualified, the STM32 forwards the final release signal to the PLC, allowing the mold to flow to the next station. If the judgment is unqualified or an equipment abnormality occurs, the STM32 blocks the release signal and locks the production line.

5. The precise measurement method for concrete pouring in a subway segment assembly line according to claim 4, characterized in that, In S2, when the weighing data changes from an upward trend to a stable state, the specific implementation of determining that the steel mold is completely removed from the production line track is as follows: the dynamic weighing determination unit monitors the data of four weighing sensors in real time. When the fluctuation value of all data is less than the preset threshold within a preset time, the weight data is determined to have reached a stable state, that is, the steel mold is confirmed to be completely suspended.

6. The precise measurement method for concrete pouring in a subway segment assembly line according to claim 4, characterized in that, The specific process of the STM32 in S4 intercepting the original station release signal output by the PLC and initiating the secondary weighing process based on the intercepted signal is as follows: The STM32's PLC signal processing unit listens to the PLC's output port. When it detects the rising or falling edge of the release signal issued by the PLC, it intercepts the signal inside the STM32 and prevents it from being directly transmitted to the pipeline drive mechanism. At the same time, it uses the intercepted signal as a trigger command to start the secondary weighing process. Before the secondary weighing is completed, the release signal is held inside the STM32, and the pipeline is in a waiting state.

7. The precise measurement method for concrete pouring in a subway segment assembly line according to claim 4, characterized in that, The STM32 dynamically adjusts the operating parameters of multiple electric jacks to ensure their synchronization during lifting and lowering. It relies on an upper limit photoelectric switch to achieve physical hardware protection against lifting overtravel and a lower limit photoelectric switch to ensure the timing safety of process switching. If the secondary weighing fails, the STM32 uploads the failure data to the host computer via wireless 485 communication and triggers an audible and visual warning. Only after manual intervention and successful re-inspection can the STM32 forward the final release signal to the PLC.

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