Intelligent control system and method for dynamically adjusting prestress of composite material

Abstract

The invention relates to the technical field of composite material forming processing, in particular to an intelligent control system and method for dynamically adjusting prestress of a composite material, the system is designed in a layered mode according to an execution layer, a data processing layer and a decision layer, the execution layer comprises a layering belt, a prestress test bed and a curing oven, and the test bed adopts a fixed table top and a bottom plate which are arranged up and down; a left supporting roller assembly and a right supporting roller assembly are symmetrically arranged on the two sides, and height adjusting bolts are arranged at the bottom of the floating table top and matched with a prestress adjusting module and a prestress sensing module to achieve layer laying belt prestress adjustment and control. The data processing layer completes signal conversion, and the decision-making layer generates an adjustment strategy through multi-algorithm fusion analysis. The method comprises the five steps of preparation, initialization, data acquisition and processing, dynamic regulation and control and ending, and precise dynamic regulation and control of prestress in the whole curing process are achieved based on the closed-loop process. According to the scheme, the problem of component defects caused by residual stress is solved, the forming precision and the mechanical property are improved, and the method is suitable for high-end composite material forming machining.

Description

Technical Field

[0001] This invention relates to the field of composite material molding and processing technology, and more particularly to an intelligent control system and method for dynamically adjusting the prestress of composite materials. It is especially suitable for the precise control of residual stress during the curing process of carbon fiber reinforced polymer composites, and belongs to the field of intelligent equipment technology for composite material molding. Background Technology

[0002] Carbon fiber reinforced polymer composites are widely used in high-end fields such as aerospace, rail transportation, and new energy due to their excellent properties such as high specific strength, high specific modulus, and corrosion resistance. The traditional curing process for carbon fiber reinforced polymer composite products includes heating, heat preservation, and cooling. In the initial gel stage of curing, residual stress is difficult to accumulate significantly because the resin-fiber interface has not yet fully formed. Even in the later stages of the curing reaction, the viscoelastic characteristics of the resin can still alleviate the residual stress generated during curing to some extent through stress relaxation effects, due to the high-temperature environment of the reaction.

[0003] However, during the final cooling stage of the curing process, the composite material undergoes a transition from a high-temperature state to a room-temperature environment. Due to the chemical shrinkage of the resin and the mismatch in the coefficients of thermal expansion between the fiber and the matrix material, residual stress is often induced inside the composite material, which leads to the deterioration of the overall mechanical properties and structural performance of the material, affecting the performance and reliability of carbon fiber composite materials. It can also cause deformation, warping, or even cracking of components, and in severe cases, it can cause the components to be scrapped.

[0004] To mitigate these adverse effects, existing technologies can reduce residual stress by optimizing curing process parameters, utilizing low-temperature curing resin systems, and employing fiber prestressing techniques. Among these, fiber prestressing technology, by creating a specific initial strain field within the composite material structure, compensates for strain differences and counteracts the warping or bending deformation that would occur during the curing stage after the prestress is released. It is considered a superior option for improving the performance of polymer-based composite materials, effectively regulating the internal stress level of the material and thus improving its mechanical properties.

[0005] However, existing fiber prestressing technologies all involve applying a constant tension to continuous carbon fibers before the composite material cures and maintaining this tension throughout the curing process. This method ignores the evolution of residual stress—the magnitude and form of residual stress generated internally vary at different stages of curing. Applying only a constant prestress cannot precisely adjust the stress state inside the composite material, thus limiting the effectiveness of fiber prestressing technology. Furthermore, existing testing benches suffer from problems such as inconsistent component markings, unreasonable support roller assembly layout, failure to distinguish between prestress adjustment and sensing modules, and improper placement of heat insulation structures. These issues lead to uneven force transmission, low testing accuracy, and susceptibility to high-temperature damage to components, further affecting the accuracy of prestress control and the stability of the device, thus restricting the molding quality and industrial application value of the composite material.

[0006] Therefore, a new technical solution is urgently needed to solve the above-mentioned technical problems. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems of the prior art and provide an intelligent control system and method for dynamically adjusting the prestress of composite materials. This system is used to solve the problems of performance degradation and component defects caused by residual stress during the curing and cooling stage of composite materials. It also overcomes the shortcomings of the prior art, such as the inability of constant tension to adapt to dynamic stress changes and the insufficient control accuracy and stability caused by unreasonable test bench layout and protection.

[0008] The above objectives are achieved through the following technical solutions: An intelligent control system for dynamically adjusting the prestress of composite materials, comprising: Execution layer: The execution layer is equipped with a prestressed test bench and a layup tape, as well as a curing oven for providing a curing environment; the prestressed test bench includes a fixed platform and a base plate arranged vertically, and a floating platform is movably arranged on the fixed platform. The bottom of the floating platform is equipped with a height adjustment bolt. A left support roller assembly and a right support roller assembly are symmetrically arranged on both sides of the fixed platform. One end of the layup tape is connected to the prestress adjustment module via the left support roller assembly, and the other end of the layup tape is connected to the prestress sensing module via the right support roller assembly, so as to realize the prestress adjustment and monitoring of the layup tape laid flat on the surface of the floating platform; the layup tape is made of composite prepreg and has an embedded FBG online sensor; Data Processing Layer: The data processing layer includes an FBG demodulator and a tensile / compression sensor data acquisition unit. The FBG demodulator is used to demodulate the stress-strain related optical signals collected by the online FBG sensor during the curing process of the layup into digital data, providing a data foundation for the analysis and prestress adjustment of the intelligent control system. The tensile / compression sensor data acquisition unit is used to perform analog-to-digital conversion on the tensile / compression analog electrical signals of the layup collected by the tensile / compression sensor, converting them into digital data for transmission to the data receiving, storage, and display unit for subsequent processing and analysis. Decision-making layer: The decision-making layer includes a data receiving, storage and display unit, an artificial intelligence platform and an intelligent control strategy generation unit. The data receiving, storage and display unit is used to receive multi-dimensional digital monitoring data uploaded by the FBG demodulator and the tensile and compressive sensor data acquisition unit, and realize data visualization display. The artificial intelligence platform couples multi-dimensional data with process curves, and judges the stress balance state through multi-algorithm fusion analysis. The intelligent control strategy generation unit generates a prestress adjustment strategy based on the analysis results, and converts it into a drive signal and sends it to the prestress adjustment module.

[0009] As a further optimization of this system, the prestressed test bench also includes a support column, a guide rail, a first slider, a first slider connecting plate, a second slider, and a second slider connecting plate; the support column is disposed between the fixed platform and the base plate, the guide rail is fixed to the fixed platform, and the first slider and the second slider are slidably connected to the two ends of the guide rail; the prestress adjustment module is connected to the first slider, and the prestress sensing module is connected to the second slider.

[0010] As a further optimization of this system, the prestress adjustment module includes a prestressing actuator, a prestressing application plate, and a first composite prepreg quick clamping mechanism; the prestressing actuator and the first slider connecting plate are respectively connected to the prestressing application plate, the first slider connecting plate is fixedly connected to the first slider, and the first composite prepreg quick clamping mechanism is disposed on the first slider connecting plate for fixing one end of the layup tape.

[0011] As a further optimization of this system, the prestress sensing module includes a sensor mounting base, a tension / compression sensor, a tension / compression sensor connecting plate, and a second composite prepreg quick clamping mechanism; the sensor mounting base is fixedly connected to the base plate, one end of the tension / compression sensor is connected to the sensor mounting base and the other end is connected to the tension / compression sensor connecting plate, the tension / compression sensor connecting plate is connected to the second slider connecting plate, the second slider connecting plate is fixedly connected to the second slider, and the second composite prepreg quick clamping mechanism is disposed on the upper surface of the second slider connecting plate for fixing the other end of the layup tape.

[0012] As a further optimization of this system, the height of the floating platform can be finely adjusted by rotating the height adjustment bolt to ensure that the bottom surface of the layup strip is completely in contact with the floating platform.

[0013] As a further optimization of this system, the prestressed test bench also includes a heat insulation and sealing unit; the heat insulation and sealing unit is located below the fixed platform and connected to the base plate, and is embedded with heat insulation cotton of replaceable thickness. The thickness of the heat insulation cotton is adapted to the curing temperature requirements of the layup tape, and is used to isolate the high temperature of the curing oven to prevent the components below the fixed platform from being damaged by high temperature.

[0014] As a further optimization of this system, the left support roller assembly and the right support roller assembly have the same structure, both including a support roller mounting base and a support roller. The support roller is connected to the support roller mounting base through a bearing to reduce friction during the transmission of the layup belt.

[0015] A smart control method for dynamically adjusting the prestress of composite materials includes the following steps: S1. Preparation stage: Lay the composite prepreg to form a layup tape, and embed FBG online sensors inside and on the surface of the layup tape; clamp and fix one end of the layup tape to the first composite prepreg quick clamping mechanism via the left support roller assembly, and clamp and fix the other end to the second composite prepreg quick clamping mechanism via the right support roller assembly; rotate the height adjustment bolt to make the layup tape flat and adhere to the surface of the floating platform. S2. Initialization stage: According to the curing temperature requirements of the layup tape, select and embed the insulation cotton of the corresponding thickness into the heat insulation sealing unit and fix it to the base plate; move the prestress test bench to the temperature uniform area in the curing oven, apply the preset initial prestress to the layup tape through the prestress adjustment module, and monitor it in real time by the tension and compression sensors until the prestress value stabilizes within the preset range; set the curing process curve and start the curing oven to start heating. S3. Data Acquisition and Processing Stage: Throughout the curing process, the FBG online sensor collects the stress and strain optical signals of the layup strip in real time, the tension and compression sensor collects the tension and compression analog electrical signals of the layup strip, and the temperature sensor collects the temperature signals inside the curing oven. After receiving the above signals, the data processing layer demodulates the optical signals into digital data through the FBG demodulator, and converts the analog electrical signals into digital data through the tension and compression sensor data acquisition unit, and transmits them synchronously to the data receiving, storage and display unit. S4. Dynamic Adjustment Stage: The data receiving, storage, and display unit stores and visualizes multi-dimensional digital data; the artificial intelligence platform calls a preset algorithm, couples the digital data with the solidified process curve, and analyzes and judges the current stress balance state of the ply strip; if the stress state does not meet the preset requirements, the intelligent control strategy generation unit generates a targeted prestress adjustment strategy and converts it into a drive signal to be sent to the prestress adjustment module to control the prestress actuator to adjust the prestress of the ply strip; if the stress state meets the preset requirements, the current prestress parameters are maintained. S5. End stage: Repeat steps S3-S4 until the curing oven completes the cooling process according to the preset process curve, then shut down the curing oven and all monitoring modules to complete the curing and dynamic control of the prestress of the layup.

[0016] As a further optimization of this method, in step S4, the artificial intelligence platform integrates at least two algorithms from the following: CNN, SVM, random forest, particle swarm optimization, linear regression, decision tree, and genetic algorithm.

[0017] As a further optimization of this method, the prestressing actuator is a servo linear motor or a servo hydraulic cylinder.

[0018] As a further optimization of this method, both the first composite prepreg quick clamping mechanism and the second composite prepreg quick clamping mechanism adopt a lever-type locking structure.

[0019] This invention provides an intelligent control system and method for dynamically adjusting the prestress of composite materials. Through a layered architecture and multi-algorithm fusion analysis, combined with symmetrical support roller assemblies and height adjustment bolts, it achieves dynamic control of prestress throughout the curing process, ensuring uniform tensile force transmission, adapting to different working conditions, and improving the molding accuracy and mechanical properties of components. Compared with existing technologies, the specific beneficial effects are as follows: 1. Precise stress control: The combination of a layered architecture and multi-algorithm fusion analysis enables dynamic adjustment of prestress throughout the curing process; 2. Reasonable structural layout: The left and right support roller assemblies are symmetrically arranged and work in conjunction with the separate adjustment and sensing modules to ensure uniform force transmission, while the heat insulation and sealing unit effectively protects high-temperature components; 3. High adaptability: The height of the floating platform can be finely adjusted by adjusting bolts, and the thickness of the insulation cotton can be selected to adapt to different lay-up tapes and curing temperature requirements; 4. Excellent molding quality: Effectively offsets residual stress, improves the molding accuracy and mechanical properties of components, and reduces the scrap rate; 5. High technological value: It breaks through the limitations of constant prestress and expands the application boundaries of fiber prestressing technology in the field of high-end composite material molding. Attached Figure Description

[0020] Figure 1 This is an architecture diagram of an intelligent control system for dynamically adjusting the prestress of composite materials according to the present invention; Figure 2 This is a flowchart of an intelligent control method for dynamically adjusting the prestress of composite materials according to the present invention; Figure 3 This is a schematic diagram of the prestressing test bench with heat insulation and sealing unit in the intelligent control system for dynamically adjusting the prestress of composite materials according to the present invention. Figure 4 This is a schematic diagram of the prestressing test bench in the intelligent control system for dynamically adjusting the prestress of composite materials according to the present invention; Figure 5 This is a cross-sectional view of the prestress test bench in the intelligent control system for dynamically adjusting the prestress of composite materials according to the present invention. Figure 6 This is a schematic diagram showing the connection between the height adjustment bolt and the floating and fixed platforms in an intelligent control system for dynamically adjusting the prestress of composite materials according to the present invention. Figure 7 This is a first-view structural diagram of the prestress adjustment module and the prestress sensing module in an intelligent control system for dynamically adjusting the prestress of composite materials according to the present invention. Figure 8 This is a second-view structural diagram of the prestress adjustment module and the prestress sensing module in the intelligent control system for dynamically adjusting the prestress of composite materials according to the present invention.

[0021] Illustration markings: 1-Layer tape, 2-Floating platform, 3-Support roller mounting base, 4-Support roller, 5-Support column, 6-Base plate, 7-Prestress sensing module, 8-Heat insulation sealing unit, 9-Prestressing actuator, 10-Sensor mounting base, 11-Tension and compression sensor, 12-Guide rail, 13-First slider, 14-First slider connecting plate, 15-First composite prepreg quick clamping mechanism, 16-Tension and compression sensor connecting plate, 17-Prestressing application plate, 18-Fixed platform, 19-Second slider connecting plate, 20-Second composite prepreg quick clamping mechanism, 21-Second slider, 22-Height adjustment bolt, 23-Left support roller assembly, 24-Right support roller assembly. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. The described embodiments are merely some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] like Figure 1 As shown, this solution provides an intelligent control system for dynamically adjusting the prestress of composite materials. The system is designed in layers: "execution layer - data processing layer - decision layer". The structure, composition and function of each layer are as follows: like Figures 3-8 As shown, the execution layer in this system is used to implement prestress application, data acquisition, and the provision of the curing environment, specifically including: Layup strip 1: It is formed by laying prepregs of composite materials such as carbon fiber / epoxy according to a preset layup method. An FBG online sensor is embedded inside, which is the direct object of prestress control. Prestressed test bench: Provides installation support and prestress adjustment foundation for the ply strip 1, including a fixed platform 18 and a base plate 6 set at the top and bottom, and the fixed platform 18 and the base plate 6 are connected by support columns 5; a floating platform 2 is movably set on the fixed platform 18, and a height adjustment bolt 22 is set at the bottom of the floating platform 2. A left support roller assembly 23 and a right support roller assembly 24 are symmetrically arranged on both sides of the fixed platform 18. The ply strip 1 is laid flat on the surface of the floating platform 2, one end of which is connected to the prestress adjustment module through the left support roller assembly 23, and the other end is connected to the prestress sensing module 7 through the right support roller assembly 24; Curing oven: Provides a stable temperature environment for curing the layup tape 1, and is compatible with preset curing process curves; Supporting sensing components: FBG online sensor, tensile and compressive sensor 11, and temperature sensor. The FBG online sensor is embedded in the layup tape 1, the tensile and compressive sensor 11 is integrated into the prestress sensing module 7, and the temperature sensor is set in the curing oven.

[0024] like Figure 1 As shown, the data processing layer in this system is used for data signal conversion and preprocessing, including: FBG demodulator: Demodulates the stress-strain related optical signals collected by the FBG online sensor during the curing process of the layup tape 1 into digital data, providing a basis for subsequent analysis; Tension and Compression Sensor Data Acquisition Unit: Converts the analog electrical signals of tension and compression of the ply strip 1 acquired by the tension and compression sensor 11 into digital data for transmission and processing.

[0025] like Figure 1 As shown, the decision-making layer in this system is used for data processing, analysis, decision-making, and control command generation, including: Data receiving, storage and display unit: Receives multi-dimensional digital monitoring data uploaded by the data processing layer, and realizes local data storage and visualization curve display; Artificial intelligence platform: Deployed on an offline server, integrating at least two algorithms, coupling curing process parameter curves with multi-dimensional monitoring data, and analyzing and judging the current stress balance state of layup strip 1; Intelligent control strategy generation unit: Based on the analysis results of the artificial intelligence platform, it generates a targeted prestress adjustment strategy and converts the strategy into a drive signal that can be recognized by the prestress actuator 9.

[0026] like Figures 3-8 As shown, the specific structure of the prestressed test bench in this system is as follows: In this system, the prestressed test bench uses a base plate 6 as the basic support component. The base plate is made of thick steel plate, with precisely machined positioning holes, sensor mounting positions 10, and connection points for the heat insulation and sealing unit 8. Anti-slip pads are fitted to the bottom to ensure overall stability. High-strength steel support columns 5 are evenly distributed between the base plate 6 and the fixed platform 18. These support columns 5 are securely connected to ensure the fixed platform 18 maintains a good level, providing a stable reference for the installation of various components and subsequent prestress control. The fixed platform 18 is also made of thick steel plate, with guide rail grooves and pre-drilled holes on its surface. These serve to support various components and forces on the upper layer and provide space for the installation of the guide rail 12. The guide rail 12 can be fixed within the guide rail groove, providing smooth sliding guidance for the first slider 13 and the second slider 21.

[0027] The first slider 13 is slidably connected to the left end of the guide rail 12 and is fixedly connected to the first slider connecting plate 14 made of rectangular aluminum alloy, which can drive the prestress adjustment module to move synchronously. The bottom of the first slider connecting plate 14 is firmly connected to the first slider 13, and the top is equipped with a first composite material prepreg quick clamping mechanism 15 with a lever-type locking structure. This clamping mechanism can easily fix and disassemble one end of the layup tape 1. One side is connected to the prestress application plate 17 with a high-strength alloy structure. The other end of the prestress application plate 17 is connected to the prestress execution mechanism 9 integrated into the prestress adjustment module. The prestress execution mechanism 9 adopts a servo linear motor or servo hydraulic cylinder, which can receive drive signals and output stable drive force. Through the force transmission between the prestress application plate 17 and the first slider connecting plate 14, the prestress of the layup tape 1 is applied. The second slider 21 is slidably connected to the right end of the guide rail 12 and fixed to the second slider connecting plate 19 made of rectangular aluminum alloy. The top of the second slider connecting plate 19 is equipped with a second composite prepreg quick clamping mechanism 20 with the same structure as the first composite prepreg quick clamping mechanism 15, which is used to fix the other end of the layup tape 1. One side of it is connected to the T-shaped steel tension and compression sensor connecting plate 16, and the other end of the tension and compression sensor connecting plate 16 is connected to the tension and compression sensor 11. The tension and compression sensor 11 is integrated into the prestress sensing module and is stably installed by the steel sensor fixing seat 10 fixed to the base plate 6. It can collect the tension and compression data of the layup tape 1 in real time and transmit it to the subsequent processing unit.

[0028] A lightweight alloy floating platform 2 is movably mounted above the fixed platform 18. The surface of the floating platform 2 is polished to reduce friction with the layup tape 1. A height adjustment bolt 22 is installed at its bottom; rotating the bolt allows for fine-tuning of the floating platform 2's height, ensuring complete contact between the layup tape 1 and the floating platform 2, effectively preventing localized stress concentration. A left support roller assembly 23 and a right support roller assembly 24 are symmetrically fixed on both sides of the fixed platform 18. Both assemblies have identical structures, using support roller mounting seats 3 as their mounting carriers. The support roller mounting seats 3 have bearing mounting holes on their surfaces. The support rollers 4 are connected to the support roller mounting seats 3 via deep groove ball bearings. The two support roller assemblies work together to guide and transmit the layup tape 1. The deep groove ball bearings significantly reduce frictional resistance during the transmission of the layup tape 1, ensuring uniform prestress transfer. In this embodiment, support rollers 4 are symmetrically arranged above and below each support roller assembly.

[0029] In addition, a heat insulation and sealing unit 8 is connected between the fixed platform 18 and the base plate 6. The unit is equipped with heat insulation cotton of replaceable thickness according to the curing temperature requirements of the layup strip 1. It can effectively isolate the high temperature generated by the curing oven and provide good protection for various components under the test platform, ensuring that the entire test platform can operate stably under complex working conditions. All components work together to achieve precise adjustment and real-time monitoring of the prestress of the layup strip 1.

[0030] This solution also provides an intelligent control method for dynamically adjusting the prestress of composite materials. This method is based on the above system and the steps are as follows: S1. Preparation stage: Lay the composite prepreg in a preset layup pattern to form layup tape 1, and implant FBG online sensors at the layup interface and corresponding positions on the surface. After guiding one end of layup tape 1 through left support roller assembly 23, clamp and fix it to the first composite prepreg quick clamping mechanism 15, and after guiding the other end through right support roller assembly 24, clamp and fix it to the second composite prepreg quick clamping mechanism 20. Rotate height adjustment bolt 22 to finely adjust the height of floating platform 2 to ensure that layup tape 1 is flat and adheres to the surface of floating platform 2 without wrinkles or suspension.

[0031] S2. Initialization stage: Based on the curing temperature requirements of the composite prepreg used in the layup tape 1, select insulation cotton of corresponding thickness, embed it into the heat insulation sealing unit 8 and fix it to the base plate 6; move the assembled prestress test bench to the temperature uniform area inside the curing oven; start the prestress actuator 9 of the prestress adjustment module to apply the preset initial prestress to the layup tape 1, and monitor the prestress value in real time through the tension and compression sensors 11 of the prestress sensing module 7 until the value stabilizes within the preset range; set the preset curing process curve in the curing oven control system and start the curing oven to begin heating.

[0032] S3. Data Acquisition and Processing Stage: Throughout the curing process, the FBG online sensor continuously acquires the stress-strain optical signal of the layup 1 in real time, the tensile-compression sensor 11 continuously acquires the tensile-compression analog electrical signal of the layup 1, and the temperature sensor in the curing oven continuously acquires the temperature signal inside the oven. The data processing layer simultaneously receives the above three types of signals. The FBG demodulator demodulates the stress-strain optical signal into digital stress-strain data, the tensile-compression sensor data acquisition unit converts the tensile-compression analog electrical signal into digital tensile-compression data, and the temperature signal is converted into digital temperature data by the matching conversion unit. The three types of digital data are then synchronously transmitted to the data receiving, storage, and display unit.

[0033] S4. Dynamic Adjustment Stage: The data receiving, storage, and display unit stores the received multi-dimensional digital data in real time and displays it in the form of a visual curve for easy monitoring by operators. The artificial intelligence platform calls at least two preset fusion algorithms to couple and analyze the multi-dimensional digital data with the preset curing process curve. Based on the preset stress balance threshold, it determines whether the current stress state of the layup strip 1 meets the requirements. If the stress state does not meet the preset requirements, the intelligent control strategy generation unit immediately generates a targeted prestress adjustment strategy and converts the adjustment strategy into a drive signal that the prestress actuator 9 can recognize. This signal is then sent to the prestress adjustment module to control the action of the prestress actuator 9, thereby realizing the dynamic adjustment of the prestress of the layup strip 1. If the stress state meets the preset requirements, the current prestress parameters remain unchanged.

[0034] S5. Ending stage: Repeat the closed-loop process of "data acquisition-processing-analysis-control" in steps S3-S4 until the curing oven completes the entire cooling process according to the preset process curve and the layup strip 1 is cured and formed; shut down the curing oven, data processing layer and decision layer modules, release the fixation of the layup strip 1 by the first composite prepreg quick clamping mechanism 15 and the second composite prepreg quick clamping mechanism 20, take out the formed component, and complete the entire curing and prestress dynamic control process.

[0035] As a specific embodiment of this solution, this embodiment takes carbon fiber / epoxy layup strip 1 as an example, including: I. Assembly and Debugging of the Prestressed Test Bench 1. Assembly: Fix the support column 5 to the base plate 6, install the fixed platform 18 and adjust its level; fix the guide rail 12 to the fixed platform 18, and install the first slider 13 and the second slider 21; symmetrically assemble the left support roller assembly 23 and the right support roller assembly 24 on both sides of the fixed platform 18; connect the prestressing actuator 9, the prestressing application plate 17, the first slider connecting plate 14 and the first composite material prepreg quick clamping mechanism 15 in sequence; connect the sensor fixing seat 10, the tension and compression sensor 11, the tension and compression sensor connecting plate 16, the second slider connecting plate 19 and the second composite material prepreg quick clamping mechanism 20; install the height adjustment bolt 22 at the bottom of the floating platform 2, and then assemble the floating platform 2 to the fixed platform 18; finally, assemble the heat insulation sealing unit 8.

[0036] 2. Debugging: Test the communication stability between the FBG online sensor and the FBG demodulator; drive the prestressed actuator 9 to move back and forth to verify the smooth sliding of the first slider 13 and the second slider 21; clamp the simulated sample to test the accuracy of the tensile and compressive sensor 11; rotate the height adjustment bolt 22 to verify the height adjustment function of the floating platform 2; simulate the curing temperature environment to test the protective effect of the heat insulation sealing unit 8 on the internal components.

[0037] II. The execution of intelligent control methods includes: S1. Preparation stage: The carbon fiber / epoxy prepreg is laid in a preset layup pattern to form a layup tape 1. FBG online sensors are implanted at the layup interface and corresponding positions on the surface of the tape. One end of the layup tape 1 is guided by the left support roller assembly 23 and fixed to the first composite prepreg quick clamping mechanism 15. The other end is guided by the right support roller assembly 24 and fixed to the second composite prepreg quick clamping mechanism 20. The height adjustment bolt 22 is rotated to make the layup tape 1 flat and adhered. S2. Initialization stage: Select and embed thermal insulation cotton of corresponding thickness into the heat insulation sealing unit 8 and fix it. Move the prestress test bench to the temperature uniform area in the curing oven. Start the prestress actuator 9 to apply the initial prestress. The tensile and compressive sensors 11 monitor the values ​​until they are stable within the preset range. Set the curing process curve and start the curing oven. S3. Data Acquisition and Processing Stage: During the heating stage, the FBG online sensor collects stress and strain data fluctuations, the tensile and compressive sensor 11 collects tensile data in real time, and the temperature sensor collects the furnace temperature synchronously. The three types of signals are converted into digital data by the data processing layer and transmitted to the data receiving, storage and display unit. S4, Dynamic Adjustment Stage: The data receiving, storage, and display unit displays temperature-time, stress-time, and tension-time data in curve form; the artificial intelligence platform uses two fusion algorithms to couple the data with the process curves, determines that the current stress state does not meet the balance requirements, and generates a targeted adjustment strategy; the intelligent control strategy generation unit converts this into a driving signal to control the prestressing actuator 9 to adjust the prestress of the layup strip 1; during the heat preservation stage, the stress state is stable, and the current prestress is maintained; during the cooling stage, residual stress is generated, and after algorithm analysis, an adjustment strategy is generated to drive the prestressing actuator 9 to adjust; S5. End stage: The curing oven completes the cooling process according to the preset process curve, automatically shuts down, and all monitoring modules stop working; release the fixation of the first composite prepreg quick clamping mechanism 15 and the second composite prepreg quick clamping mechanism 20, take out the molding layup belt 1 component, and complete the adjustment.

[0038] The above description is merely illustrative of the embodiments of the present invention and is not intended to limit the present invention. For those skilled in the art, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An intelligent control system for dynamically adjusting the prestress of composite materials, characterized in that, include: Execution layer: The execution layer is provided with a prestress test bench and a layup tape (1), as well as a curing oven for providing a curing environment; the prestress test bench includes a fixed platform (18) and a base plate (6) arranged on the upper and lower sides, a floating platform (2) is movably arranged on the fixed platform (18), a height adjustment bolt (22) is provided at the bottom of the floating platform (2), and a left support roller assembly (23) and a right support roller assembly (24) are symmetrically arranged on both sides of the fixed platform (18). One end of the layup tape (1) is connected to the prestress adjustment module through the left support roller assembly (23), and the other end of the layup tape (1) is connected to the prestress sensing module (7) through the right support roller assembly (24), so as to realize the prestress adjustment and monitoring of the layup tape (1) laid flat on the surface of the floating platform (2); the layup tape (1) is made of composite prepreg and has an embedded FBG online sensor; Data processing layer: The data processing layer includes an FBG demodulator and a tensile and compressive sensor data acquisition unit. The FBG demodulator is used to demodulate the stress-strain related optical signal collected by the FBG online sensor during the curing process of the layup tape (1) into digital data. The tensile and compressive sensor data acquisition unit is used to perform analog-to-digital conversion on the tensile and compressive analog electrical signal of the layup tape (1) collected by the tensile and compressive sensor (11) and convert it into digital data. Decision layer: The decision layer includes a data receiving, storage and display unit, an artificial intelligence platform and an intelligent control strategy generation unit. The data receiving, storage and display unit is used to receive multi-dimensional digital monitoring data uploaded by the FBG demodulator and the tensile and compressive sensor data acquisition unit, and realize data visualization display. The artificial intelligence platform couples multi-dimensional data with process curves, and judges the stress balance state through multi-algorithm fusion analysis. The intelligent control strategy generation unit generates a prestress adjustment strategy based on the analysis results and converts it into a drive signal to be sent to the prestress adjustment module.

2. The intelligent control system for dynamically adjusting the prestress of composite materials according to claim 1, characterized in that, The prestressed test bench also includes a support column (5), a guide rail (12), a first slider (13), a first slider connecting plate (14), a second slider (21), and a second slider connecting plate (19); the support column (5) is disposed between the fixed platform (18) and the base plate (6), the guide rail (12) is fixed to the fixed platform (18), and the first slider (13) and the second slider (21) are slidably connected to the two ends of the guide rail (12); the prestress adjustment module is connected to the first slider (13), and the prestress sensing module (7) is connected to the second slider (21).

3. The intelligent control system for dynamically adjusting the prestress of composite materials according to claim 2, characterized in that, The prestress adjustment module includes a prestressing actuator (9), a prestressing application plate (17), and a first composite prepreg quick clamping mechanism (15). The prestressing actuator (9) and the first slider connecting plate (14) are respectively connected to the prestressing application plate (17). The first slider connecting plate (14) is fixedly connected to the first slider (13). The first composite prepreg quick clamping mechanism (15) is disposed on the first slider connecting plate (14) and is used to fix one end of the layup strip (1).

4. The intelligent control system for dynamically adjusting the prestress of composite materials according to claim 2, characterized in that, The prestress sensing module (7) includes a sensor mounting base (10), a tension / compression sensor (11), a tension / compression sensor connecting plate (16), and a second composite prepreg quick clamping mechanism (20). The sensor mounting base (10) is fixedly connected to the base plate (6). One end of the tension / compression sensor (11) is connected to the sensor mounting base (10), and the other end is connected to the tension / compression sensor connecting plate (16). The tension / compression sensor connecting plate (16) is connected to the second slider connecting plate (19). The second slider connecting plate (19) is fixedly connected to the second slider (21). The second composite prepreg quick clamping mechanism (20) is disposed on the upper surface of the second slider connecting plate (19) and is used to fix the other end of the layup tape (1).

5. The intelligent control system for dynamically adjusting the prestress of composite materials according to claim 1, characterized in that, The height of the floating platform (2) can be finely adjusted by rotating the height adjustment bolt (22) to ensure that the layup strip (1) is fully attached to the floating platform (2).

6. The intelligent control system for dynamically adjusting the prestress of composite materials according to claim 1, characterized in that, The prestressed test bench also includes a heat insulation and sealing unit (8); the heat insulation and sealing unit (8) is located below the fixed platform (18) and connected to the base plate (6), and is embedded with heat insulation cotton of replaceable thickness. The thickness of the heat insulation cotton is adapted to the curing temperature requirements of the layup tape (1) and is used to isolate the high temperature of the curing oven to prevent the components below the fixed platform (18) from being damaged by high temperature.

7. The intelligent control system for dynamically adjusting the prestress of composite materials according to claim 1, characterized in that, The left support roller assembly (23) and the right support roller assembly (24) have the same structure, both including a support roller mounting seat (3) and a support roller (4). The support roller (4) is connected to the support roller mounting seat (3) through a bearing to reduce friction during the transmission of the layup belt (1).

8. A control method for an intelligent control system based on the dynamic adjustment of composite material prestress as described in any one of claims 1-7, characterized in that, Includes the following steps: S1, Preparation stage: Lay the composite prepreg to form a layup tape (1), and implant FBG online sensors inside and on the surface of the layup tape (1); clamp and fix one end of the layup tape (1) to the first composite prepreg quick clamping mechanism (15) via the left support roller assembly (23), and clamp and fix the other end to the second composite prepreg quick clamping mechanism (20) via the right support roller assembly (24); rotate the height adjustment bolt (22) to make the layup tape (1) flat and adhere to the surface of the floating table (2); S2, Initialization stage: According to the curing temperature requirements of the layup tape (1), select and embed the insulation cotton of corresponding thickness into the heat insulation sealing unit (8) and fix it to the base plate (6); move the prestress test bench to the temperature uniform area in the curing oven, apply the preset initial prestress to the layup tape (1) through the prestress adjustment module, monitor it in real time by the tension and pressure sensor (11) until the prestress value is stable within the preset range; set the curing process curve and start the curing oven to start heating; S3. Data Acquisition and Processing Stage: Throughout the curing process, the FBG online sensor collects the stress-strain optical signal of the layup strip (1) in real time, the tension and compression sensor (11) collects the tension and compression analog electrical signal of the layup strip (1), and the temperature sensor collects the temperature signal inside the curing oven. After receiving the above signals, the data processing layer demodulates the optical signal into digital data through the FBG demodulator, and converts the analog electrical signal into digital data through the tension and compression sensor data acquisition unit, and transmits it synchronously to the data receiving, storage and display unit. S4, Dynamic Control Stage: The data receiving, storage, and display unit stores and visualizes multi-dimensional digital data; The artificial intelligence platform calls a preset algorithm, couples digital data with curing process curves, and analyzes and judges the current stress balance state of the layup strip (1); If the stress state does not meet the preset requirements, the intelligent control strategy generation unit generates a targeted prestress adjustment strategy and converts it into a drive signal to be sent to the prestress adjustment module to control the prestress actuator (9) to adjust the prestress of the layup strip (1); If the stress state meets the preset requirements, maintain the current prestress parameters; S5. End stage: Repeat steps S3-S4 until the curing oven completes the cooling process according to the preset process curve, shut down the curing oven and each monitoring module, and complete the curing and prestress dynamic control of the layup strip (1).

9. The intelligent control method for dynamically adjusting the prestress of composite materials according to claim 8, characterized in that, In step S4, the artificial intelligence platform integrates at least two algorithms from CNN, SVM, random forest, particle swarm optimization, linear regression, decision tree, and genetic algorithm.

10. The intelligent control method for dynamically adjusting the prestress of composite materials according to claim 8, characterized in that, The prestressing actuator (9) is a servo linear motor or a servo hydraulic cylinder.

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