Die-free mirror image fiber placement method and die-free mirror image fiber placement system

Abstract

The invention belongs to the technical field of material processing, relates to a mold-free mirror image fiber placement method and a mold-free mirror image fiber placement system, and aims at improving the production flexibility and efficiency by laying fiber ribbons in a mirror symmetry manner without a mold. According to the method, the temperature and pressure of a ribbon are obtained in real time, the output power of a heater and the modified value of the path of a fiber placement tail end movement mechanism are calculated through the temperature difference and the pressure difference, controller parameters are optimized through reinforcement learning, and stable control over the temperature and the pressure is achieved. The system comprises a hardware part and a control system, the hardware part comprises a pressure part, a heat source part and other parts, and the control system ensures the fiber placement quality through real-time feedback adjustment. The problem that the temperature and the pressure are difficult to accurately control in the mold-free mirror image fiber placement process is solved, and the performance of a composite product is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of material processing, and relates to a moldless mirror image wire placing method and a moldless mirror image wire placing system. Background Art

[0002] In the field of material processing, wire laying technology, as a key process for composite material manufacturing, is widely used in the production of complex components such as aircraft wings. Traditional wire laying technology relies on pre-manufactured metal molds, which need to be customized according to the curved surface shape of the component. It is not only time-consuming and material-consuming, but also requires a separate mold for each different component, which greatly limits the flexibility and efficiency of production. In addition, the design and manufacturing process of the mold is complex and has high technical requirements, which further increases the technical threshold and cost investment.

[0003] In the field of material processing, mirror processing technology usually refers to the use of two or more sets of identical or symmetrical processing equipment to perform processing operations on both sides of the workpiece to be processed simultaneously, so as to achieve accurate and symmetrical processing of the workpiece. In theory, if the mirror processing technology can be combined with the wire laying process, two sets of identical wire laying equipment are used, located on both sides of the workpiece to be processed, and the two are in mirror-symmetrical positions. The two devices can provide each other with necessary support during the wire laying process without the need for molds, thus realizing moldless wire laying. However, this idea is extremely difficult to achieve because:

[0004] 1. During the wire laying process, the curing heat is provided by heaters on both sides, resulting in a complex and unstable heat transfer path. With the increase in the number of wire laying layers and the change in the structure of the middle layer, the heat transfer effect on the opposite side becomes unpredictable, which in turn causes temperature fluctuations. Such temperature fluctuations will directly affect the curing quality of thermoplastic resins and may cause serious problems such as material performance degradation, brittle cracks, and even combustion.

[0005] 2. If two driven rollers are used to squeeze each other to generate compaction pressure, the pressure may fluctuate violently due to the power source, small contact area and high curvature of the rollers. Unstable pressure not only affects the filling effect of the resin on the fiber gap, but may also form bubbles or voids, reduce the mechanical properties of the composite material, and may also cause excessive extrusion of the resin, resulting in uneven bonding between the fibers and weakening the interlayer peeling strength of the composite material.

[0006] 3. In the process of wire laying, it is usually necessary to use robotic arms, gantries, etc. as motion mechanisms. The motion accuracy and rigidity of these motion mechanisms themselves are relatively low, far lower than machine tools, which increases the difficulty of pressure and temperature control during the wire laying process.

[0007] Therefore, if we want to combine the mirror processing technology with the wire laying process, the problem that needs to be solved is: how to accurately control the temperature and pressure during the wire laying process.

[0008] Currently, there are some technologies for controlling temperature and pressure. For example, patent application US202117401138A discloses an in-situ monitoring method for compaction rollers in a composite material laying process. It uses an infrared thermal imager to collect temperature data for online monitoring and feedback control. However, this patent application is for traditional mold laying or plane laying scenarios. It infers the defects of composite materials by analyzing the temperature profile of the pressure roller. This method is easily affected by various factors and is not suitable for moldless laying.

[0009] In addition, the existing pressure control technology is usually based on the prediction of compaction force based on the mold (for example, literature "Modeling and experimental validation of compaction pressure distribution for automated fiber placement, Composite Structures, Volume 256, 2021, 113101, ISSN0263-8223", "Pressure distribution for automated fiber placement and design optimization of compaction rollers. Journal of Reinforced Plastics and Composites. 2019; 38(18): 860-870"), which is also not suitable for moldless wire placement. Summary of the invention

[0010] The purpose of the present invention is to solve the problems existing in the prior art and to provide a moldless mirror image wire placing method and a moldless mirror image wire placing system.

[0011] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0012] A moldless mirror-image laying method, which does not use a mold, lays two ribbons in a mirror-symmetrical manner, and repeats the laying process multiple times;

[0013] During the laying process, the actual ribbon temperature is obtained in real time and the temperature difference is calculated in real time. The modified value of the heater output power is calculated in real time according to the temperature difference, and the heater output power is updated in real time.

[0014] Temperature difference = actual ribbon temperature - target ribbon temperature difference;

[0015] Modified value of heater output power = kp*×T+ki*×ΣT+kd*×ΔT;

[0016] Wherein, T is the temperature difference at the current moment of the current wire laying process, ΣT is the sum of all temperature differences of the current wire laying process up to the current moment, ΔT = the temperature difference at the current moment of the current wire laying process - the temperature difference at the previous moment of the current wire laying process; kp*, ki*, kd* are controller parameter combinations that meet the requirements and are found by simulation in a virtual environment and continuous iterative optimization using a reinforcement learning model;

[0017] During the laying process, the real wire pressure is obtained in real time and the pressure difference is calculated in real time. The modified value of the path of the end-of-laying motion mechanism (robotic arm or other motion mechanism, such as any single-axis or multi-axis motion actuator such as gantry) is calculated in real time according to the pressure difference, and the path of the end-of-laying motion mechanism is updated in real time.

[0018] Pressure difference = actual ribbon pressure - target ribbon pressure;

[0019] Modified value of the path of the motion mechanism at the end of the wire laying process = kp'×P+ki'×ΣP+kd'×ΔP;

[0020] Wherein, P is the pressure difference at the current moment of the current wire laying process, ΣP is the sum of all pressure differences of the current wire laying process up to the current moment, ΔP = the pressure difference at the current moment of the current wire laying process - the pressure difference at the previous moment of the current wire laying process; kp', ki', kd' are controller parameter combinations that meet the requirements and are found by simulation in a virtual environment and continuous iterative optimization using a reinforcement learning model.

[0021] As the preferred technical solution:

[0022] In a patternless mirror-image placing method as described above, kp*, ki*, and kd* are obtained by the following process:

[0023] (a) Generate a set of kp, ki, kd;

[0024] (b) Let i = 1;

[0025] (c) The same simulation as the actual process is performed in the virtual space, and the i-th wire laying process begins;

[0026] (d) Let j = 1, let the virtual heater output power = the heater output power in the actual process;

[0027] (e) inputting the virtual heater output power and the corresponding heating time into the prediction model A, which outputs the predicted ribbon temperature, and calculating the difference between the predicted ribbon temperature and the target ribbon temperature to obtain the jth temperature difference of the i-th temperature difference sequence;

[0028] Prediction model A is a trained deep learning model. During training, the heater output power and the corresponding heating time are used as the input of the deep learning model, and the ribbon temperature is used as the theoretical output of the deep learning model. The parameters of the deep learning model are continuously adjusted.

[0029] (f) Determine whether the i-th fiber laying process is completed. If not, calculate the modified value of the virtual heater output power using the following formula, update the virtual heater output power, set j=j+1, and return to step (e); otherwise, proceed to the next step;

[0030] The modified value of the virtual heater output power = kp×T+ki×ΣT+kd×ΔT;

[0031] Wherein, T is the jth temperature difference of the i-th temperature difference sequence, ΣT is the sum of all temperature differences of the i-th temperature difference sequence, ΔT = the jth temperature difference of the i-th temperature difference sequence - the j-1th temperature difference of the i-th temperature difference sequence, when j = 1, let ΔT = 0;

[0032] (g) Score the ith temperature difference sequence and determine whether the score of the ith temperature difference sequence reaches the set value. If yes, output the last group of kp, ki, and kd as kp*, ki*, and kd*; otherwise, proceed to the next step;

[0033] (h) Determine whether all the wire laying processes are completed. If not, input the last set of kp, ki, kd and the i-th temperature difference sequence into the reinforcement learning model with a reward function, which outputs a new set of kp, ki, kd. After setting i=i+1, return to step (c); otherwise, report an error to inform the technician that no suitable parameters have been found, and return to step (a).

[0034] In the above-mentioned patternless mirror-image laying method, the process of obtaining the prediction model A is as follows:

[0035] (i) Establishing a data set;

[0036] Collect the heater output power, corresponding heating time and actual ribbon temperature in the same historical process as the current process;

[0037] At the same time, the same simulation as the actual process is performed in the virtual space to obtain the virtual heater output power and the corresponding heating time and virtual ribbon temperature;

[0038] (ii) Data augmentation: increasing the size of the dataset to obtain a training set;

[0039] (iii) Establish and train a deep learning model to obtain prediction model A.

[0040] In a patternless mirror-image laying method as described above, kp', ki', and kd' are obtained by the following process:

[0041] (A) Generate a set of kp, ki, kd;

[0042] (B) Let i = 1;

[0043] (C) The same simulation as the actual process is performed in the virtual space, and the i-th wire laying process begins;

[0044] (D) Let j = 1, let the virtual wire placement end motion mechanism path = the wire placement end motion mechanism path in the actual process;

[0045] (E) inputting the virtual fiber laying end motion mechanism path into the prediction model B, which outputs the predicted ribbon pressure, and calculating the difference between the predicted ribbon pressure and the target ribbon pressure to obtain the jth pressure difference of the i-th pressure difference sequence;

[0046] Prediction model B is a trained deep learning model. During training, the path of the motion mechanism at the end of the fiber laying process is used as the input of the deep learning model, and the ribbon pressure is used as the theoretical output of the deep learning model. The parameters of the deep learning model are continuously adjusted.

[0047] (F) Determine whether the i-th wire laying process is completed. If not, calculate the modification value of the virtual wire laying terminal motion mechanism path using the following formula, update the virtual wire laying terminal motion mechanism path, and set j=j+1, then return to step (E); otherwise, proceed to the next step;

[0048] The modified value of the virtual wire laying end motion mechanism path = kp×P+ki×ΣP+kd×ΔP;

[0049] Wherein, P is the jth pressure difference of the i-th pressure difference sequence, ΣP is the sum of all pressure differences of the i-th pressure difference sequence, ΔP = the jth pressure difference of the i-th pressure difference sequence - the j-1th pressure difference of the i-th pressure difference sequence, when j = 1, let ΔP = 0;

[0050] (G) Score the ith pressure difference sequence and determine whether the score of the ith pressure difference sequence reaches a set value. If yes, output the last group of kp, ki, and kd as kp', ki', and kd'; otherwise, proceed to the next step;

[0051] (H) Determine whether all the wire laying processes are completed. If not, input the last set of kp, ki, kd and the i-th pressure difference sequence into the reinforcement learning model with a reward function, which outputs a new set of kp, ki, kd, and sets i=i+1, then returns to step (C); otherwise, report an error to inform the technician that no suitable parameters have been found, and return to step (A).

[0052] In the above-mentioned patternless mirror-image laying method, the process of obtaining the prediction model B is as follows:

[0053] (I) Establishing a data set;

[0054] Collect the path of the wire laying end motion mechanism and the actual wire pressure in the historical process that is the same as the current process;

[0055] At the same time, the same simulation as the actual process is performed in the virtual space to obtain the virtual fiber placement end motion mechanism path and the virtual ribbon pressure;

[0056] (II) Data augmentation: increasing the size of the data set to obtain a training set;

[0057] (III) Establish and train a deep learning model to obtain prediction model B.

[0058] The present invention also provides a patternless mirror-image wire-laying system, including a hardware part and a control system;

[0059] The hardware part includes symmetrical left and right parts. The right part includes the main plate, pressure component, shearing component, re-feeding component, tension component, heat source component, connector, and wire laying end motion mechanism.

[0060] The pressure component includes a pressure sensor;

[0061] The heat source component includes a heater and an infrared thermal imager. The heater is used to heat the ribbon, and the infrared thermal imager is used to take real-time photos of the ribbon laying area to obtain the temperature field data of the ribbon.

[0062] The control system includes a temperature stabilization control subsystem, a pressure stabilization control subsystem, a control instruction generation subsystem, a wire placement terminal motion mechanism control subsystem, and a wire placement terminal functional mechanism control subsystem;

[0063] The infrared thermal imager is used to obtain the real ribbon temperature in real time during the laying process, and send the real ribbon temperature to the temperature stabilization control subsystem in real time;

[0064] The temperature stabilization control subsystem is used to calculate the temperature difference in real time, calculate the modified value of the heater output power in real time according to the temperature difference, and send the modified value of the heater output power to the control instruction generation subsystem in real time;

[0065] Temperature difference = actual ribbon temperature - target ribbon temperature difference;

[0066] Modified value of heater output power = kp*×T+ki*×ΣT+kd*×ΔT;

[0067] Wherein, T is the temperature difference at the current moment of the current wire laying process, ΣT is the sum of all temperature differences of the current wire laying process up to the current moment, ΔT = the temperature difference at the current moment of the current wire laying process - the temperature difference at the previous moment of the current wire laying process; kp*, ki*, kd* are controller parameter combinations that meet the requirements and are found by simulation in a virtual environment and continuous iterative optimization using a reinforcement learning model;

[0068] The pressure sensor is used to obtain the real ribbon pressure in real time during the laying process, and send the real ribbon pressure to the pressure stabilization control subsystem in real time;

[0069] The pressure stabilization control subsystem is used to calculate the pressure difference in real time, calculate the modification value of the path of the motion mechanism at the end of the fiber placement in real time according to the pressure difference, and send the modification value of the path of the motion mechanism at the end of the fiber placement to the control instruction generation subsystem in real time;

[0070] Pressure difference = actual ribbon pressure - target ribbon pressure;

[0071] Modified value of the path of the motion mechanism at the end of the wire laying process = kp'×P+ki'×ΣP+kd'×ΔP;

[0072] Wherein, P is the pressure difference at the current moment of the current laying process, ΣP is the sum of all pressure differences of the current laying process up to the current moment, ΔP = the pressure difference at the current moment of the current laying process - the pressure difference at the previous moment of the current laying process; kp', ki', kd' are controller parameter combinations that meet the requirements and are found by simulation in a virtual environment and continuous iterative optimization using a reinforcement learning model;

[0073] The control instruction generation subsystem is used to generate a control instruction according to the modified value of the heater output power and the modified value of the wire placement terminal motion mechanism path, and then send the control instruction to the wire placement terminal functional mechanism control subsystem and the wire placement terminal motion mechanism control subsystem;

[0074] The control subsystem of the functional mechanism at the end of the wire placement is used to update the heater output power in real time after processing the control instructions;

[0075] The wire placement terminal motion mechanism control subsystem is used to process the control instructions and update the wire placement terminal motion mechanism path in real time.

[0076] As the preferred technical solution:

[0077] In the above-mentioned moldless mirror-image wire laying system, the pressure component further includes a pressure roller, a support device, a heat-insulating asbestos board and a cylinder a, the central axis of the pressure roller is parallel to the front-back direction, the pressure roller, the support device, the heat-insulating asbestos board, the pressure sensor and the cylinder a are connected in sequence from left to right, the cylinder a is fixed on the main plate and is used to push the pressure roller to the left, and cooperate with the pressure roller on the opposite side to squeeze and generate compaction pressure; the heat-insulating asbestos board can isolate the heat on the pressure roller to avoid damaging the pressure sensor;

[0078] The shearing component includes a cylinder c and a blade. The cylinder c is used to drive the blade to shear the ribbon. The cylinder c is fixed on the main plate.

[0079] The heavy-feeding component includes a driving wheel, a driven wheel, a motor and a cylinder b. The driving wheel and the driven wheel are arranged vertically and parallel to the left and right directions. The motor is used to drive the driving wheel to rotate, and the cylinder b is used to press the driven wheel onto the driving wheel. The motor and the cylinder b are fixed on the main body plate. Before the silk ribbon is installed and the silk laying begins, the cylinder b is not started, and the driving wheel and the driven wheel are separated. When the silk laying begins, the silk ribbon is installed in the channel and passes between the driving wheel and the driven wheel. The cylinder b is started, and the driven wheel presses the silk ribbon onto the driving wheel to achieve the pressing of the silk ribbon. The motor drives the driving wheel to rotate during the silk laying process, driving the driven wheel to squeeze out the silk ribbon together.

[0080] The tension component includes a material reel and a brake. The material reel is used to wind the ribbon. During the wire laying process, the material reel is forced to rotate under the drive of the re-feeding component to realize the feeding of the ribbon. The brake is used to provide torque for the material reel to maintain a stable tension force for wire feeding to prevent the ribbon from being unstablely fed or even falling off due to the high-speed rotation of the material reel. The material reel and the brake are both fixed on the main plate.

[0081] The heat source component also includes a support plate, the heater is fixed on the main body plate, and the infrared thermal imager is fixed on the main body plate through the support plate;

[0082] The connecting piece is fixed on the main plate and connected to the end of the wire placement end movement mechanism.

[0083] Beneficial effects:

[0084] (1) The present invention adopts the moldless mirror wire laying technology, which abandons the dependence on molds in traditional wire laying technology, avoids the time and material costs required for mold manufacturing, and avoids the problem of different molds required for different components. This makes production more flexible and can quickly adapt to various component shapes, thereby significantly improving production efficiency.

[0085] (2) The present invention obtains the actual ribbon temperature and pressure in real time, and uses the controller parameter combination optimized by the reinforcement learning model to calculate and adjust the heater output power and the path of the end-of-laying motion mechanism in real time, thereby ensuring the stable control of temperature and pressure during the moldless mirror-shaped laying process. This effectively avoids problems such as uneven or excessive curing and degradation of material properties caused by temperature fluctuations, as well as defects such as poor bonding performance and air bubbles caused by pressure fluctuations, thereby significantly improving the final performance of composite products. BRIEF DESCRIPTION OF THE DRAWINGS

[0086] Figure 1 It is a front view structural schematic diagram of the hardware part of the patternless mirror-image wire placing system of the present invention;

[0087] Figure 2 It is a rear view structural schematic diagram of the left part of the hardware part of the patternless mirror-image wire placement system of the present invention;

[0088] Figure 3 It is a front view structural schematic diagram of the right part of the hardware part of the patternless mirror-image wire placing system of the present invention;

[0089] Figure 4 This is a schematic diagram of the ribbon installation process;

[0090] Figure 5 Comparison of the wire laying distance-temperature curve between experimental group 1 and control group 1;

[0091] Figure 6 Comparison of the laying distance-temperature curve between experimental group 2 and control group 2;

[0092] Figure 7 Comparison of the wire laying distance-temperature curve between experimental group 3 and control group 3;

[0093] Figure 8 Comparison of the laying distance-pressure curves between the experimental group 4 and the control group 4;

[0094] Fig. 9 Comparison of the laying distance-pressure curves between the experimental group 5 and the control group 5;

[0095] Fig.10 Comparison of the laying distance-pressure curves between the experimental group 6 and the control group 6;

[0096] Fig.11 This is the full flow chart of the present invention. The cycle from generating the system control instruction file to judging whether the wire laying is completed is the wire laying process flow, reward calculation, model training, PID parameter (i.e., kp, ki, kd below) adjustment, and PID parameter decision process;

[0097] Fig.12It is a logic diagram of reward calculation, model training and PID parameter adjustment of the present invention;

[0098] Among them, 1-pressure sensor, 2-cylinder a, 3-connecting part, 4-material roll, 5-support plate, 6-heater, 7-infrared thermal imager, 8-cylinder c, 9-pressure roller, 10-driving wheel, 11-cylinder b, 12-driven wheel, 13-motor, 14-blade, 15-brake, 16-insulating asbestos board, 17-main body plate, 19-ribbon, 20-bracket. DETAILED DESCRIPTION

[0099] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0100] A mirror-image wire placement system without a mold, such as Figure 1 , Figure 2 , Figure 3 , Fig.11 and Fig.12 As shown, it includes hardware parts and control system;

[0101] like Figure 1 to Figure 3 As shown, the hardware part includes a symmetrical left part and a right part, and the right part includes a main plate 17, a pressure component, a shearing component, a re-feeding component, a tension component, a heat source component, a connecting part 3, and a wire placement end movement mechanism;

[0102] like Figure 1 , Figure 3 As shown, the pressure component includes a pressure sensor 1, a pressure roller 9, a supporting device, a heat-insulating asbestos board 16 and a cylinder a2; the central axis of the pressure roller 9 is parallel to the front-back direction, the pressure roller 9, the supporting device, the heat-insulating asbestos board 16, the pressure sensor 1 and the cylinder a2 are connected in sequence from left to right, and the cylinder a2 is fixed on the main body plate 17 and is used to push the pressure roller 9 to the left;

[0103] The shearing component includes a cylinder c8 and a blade 14. The cylinder c8 is used to drive the blade 14 to shear the ribbon 19. The cylinder c8 is fixed on the main plate 17.

[0104] like Figure 2 , Figure 3As shown, the heavy-feeding component includes a driving wheel 10, a driven wheel 12, a motor 13 and a cylinder b 11. The driving wheel 10 and the driven wheel 12 are arranged vertically and parallel to the left and right directions. The motor 13 is used to drive the driving wheel 10 to rotate. The cylinder b 11 is used to press the driven wheel 12 onto the driving wheel 10. The motor 13 and the cylinder b 11 are fixed on the main body plate 17;

[0105] The tension component includes a material reel 4 and a brake 15. The material reel 4 is used to wind the ribbon 19. The brake 15 is used to provide torque for the material reel 4 to maintain a stable tension force for wire feeding. The material reel 4 and the brake 15 are both fixed on the main plate 17.

[0106] The heat source component includes a heater 6, an infrared thermal imager 7 and a support plate 5; the heater 6 is used to heat the ribbon 19; the infrared thermal imager 7 is used to photograph the wire laying area in real time to obtain temperature field data of the ribbon 19; the heater 6 is fixed on the main plate 17, and the infrared thermal imager 7 is fixed on the main plate 17 through the support plate 5;

[0107] The connecting member 3 is fixed on the main plate 17 and connected to the end of the wire placement end movement mechanism;

[0108] The control system includes a temperature stabilization control subsystem, a pressure stabilization control subsystem, a control instruction generation subsystem, a wire placement terminal motion mechanism control subsystem, and a wire placement terminal functional mechanism control subsystem;

[0109] The infrared thermal imager 7 is also used to obtain the real ribbon temperature in real time during the laying process, and send the real ribbon temperature to the temperature stabilization control subsystem in real time; the temperature stabilization control subsystem is used to calculate the temperature difference in real time, calculate the modified value of the heater output power in real time according to the temperature difference, and send the modified value of the heater output power to the control instruction generation subsystem in real time;

[0110] Temperature difference = actual ribbon temperature - target ribbon temperature difference;

[0111] Modified value of heater output power = kp*×T+ki*×ΣT+kd*×ΔT;

[0112] Wherein, T is the temperature difference at the current moment of the current wire laying process, ΣT is the sum of all temperature differences from the current wire laying process to the current moment, ΔT = the temperature difference at the current moment of the current wire laying process - the temperature difference at the previous moment of the current wire laying process; kp*, ki*, kd* are obtained through the following process:

[0113] (a) Generate a set of kp, ki, kd;

[0114] (b) Let i = 1;

[0115] (c) The same simulation as the actual process is performed in the virtual space, and the i-th wire laying process begins;

[0116] (d) Let j = 1, let the virtual heater output power = the heater output power in the actual process;

[0117] (e) inputting the virtual heater output power and the corresponding heating time into the prediction model A, which outputs the predicted ribbon temperature, and calculating the difference between the predicted ribbon temperature and the target ribbon temperature to obtain the jth temperature difference of the i-th temperature difference sequence;

[0118] The process of obtaining prediction model A is as follows:

[0119] (i) Establishing a data set;

[0120] Collect the heater output power, corresponding heating time and actual ribbon temperature in the same historical process as the current process;

[0121] At the same time, the same simulation as the actual process is performed in the virtual space to obtain the virtual heater output power and the corresponding heating time and virtual ribbon temperature;

[0122] (ii) Data augmentation: increasing the size of the dataset to obtain a training set;

[0123] (iii) Establish and train a deep learning model to obtain prediction model A;

[0124] (f) Determine whether the i-th fiber laying process is completed. If not, calculate the modified value of the virtual heater output power using the following formula, update the virtual heater output power, set j=j+1, and return to step (e); otherwise, proceed to the next step;

[0125] The modified value of the virtual heater output power = kp×T+ki×ΣT+kd×ΔT;

[0126] Wherein, T is the jth temperature difference of the i-th temperature difference sequence, ΣT is the sum of all temperature differences of the i-th temperature difference sequence, ΔT = the jth temperature difference of the i-th temperature difference sequence - the j-1th temperature difference of the i-th temperature difference sequence, when j = 1, let ΔT = 0;

[0127] (g) Score the ith temperature difference sequence and determine whether the score of the ith temperature difference sequence reaches the set value. If yes, output the last group of kp, ki, and kd as kp*, ki*, and kd*; otherwise, proceed to the next step;

[0128] (h) Determine whether all the fiber laying processes are completed. If not, input the last set of kp, ki, kd and the i-th temperature difference sequence into the reinforcement learning model with a reward function, which outputs a new set of kp, ki, kd, and sets i=i+1, then returns to step (c); otherwise, returns to step (a);

[0129] The pressure sensor 1 is used to obtain the real ribbon pressure in real time during the wire laying process, and send the real ribbon pressure to the pressure stabilization control subsystem in real time; the pressure stabilization control subsystem is used to calculate the pressure difference in real time, calculate the modification value of the wire laying terminal motion mechanism path in real time according to the pressure difference, and send the modification value of the wire laying terminal motion mechanism path to the control instruction generation subsystem in real time;

[0130] Pressure difference = actual ribbon pressure - target ribbon pressure;

[0131] Modified value of the path of the motion mechanism at the end of the wire laying process = kp'×P+ki'×ΣP+kd'×ΔP;

[0132] Wherein, P is the pressure difference at the current moment of the current laying process, ΣP is the sum of all pressure differences of the current laying process up to the current moment, ΔP = the pressure difference at the current moment of the current laying process - the pressure difference at the previous moment of the current laying process; kp', ki', kd' are obtained through the following process:

[0133] (A) Generate a set of kp, ki, kd;

[0134] (B) Let i = 1;

[0135] (C) The same simulation as the actual process is performed in the virtual space, and the i-th wire laying process begins;

[0136] (D) Let j = 1, let the virtual wire placement end motion mechanism path = the wire placement end motion mechanism path in the actual process;

[0137] (E) inputting the virtual fiber laying end motion mechanism path into the prediction model B, which outputs the predicted ribbon pressure, and calculating the difference between the predicted ribbon pressure and the target ribbon pressure to obtain the jth pressure difference of the i-th pressure difference sequence;

[0138] The acquisition process of prediction model B is as follows:

[0139] (I) Establishing a data set;

[0140] Collect the path of the wire laying end motion mechanism and the actual wire pressure in the historical process that is the same as the current process;

[0141] At the same time, the same simulation as the actual process is performed in the virtual space to obtain the virtual fiber placement end motion mechanism path and the virtual ribbon pressure;

[0142] (II) Data augmentation: increasing the size of the data set to obtain a training set;

[0143] (III) Establish and train a deep learning model to obtain prediction model B;

[0144] (F) Determine whether the i-th wire laying process is completed. If not, calculate the modification value of the virtual wire laying terminal motion mechanism path using the following formula, update the virtual wire laying terminal motion mechanism path, and set j=j+1, then return to step (E); otherwise, proceed to the next step;

[0145] The modified value of the virtual wire laying end motion mechanism path = kp×P+ki×ΣP+kd×ΔP;

[0146] Wherein, P is the jth pressure difference of the i-th pressure difference sequence, ΣP is the sum of all pressure differences of the i-th pressure difference sequence, ΔP = the jth pressure difference of the i-th pressure difference sequence - the j-1th pressure difference of the i-th pressure difference sequence, when j = 1, let ΔP = 0;

[0147] (G) Score the ith pressure difference sequence and determine whether the score of the ith pressure difference sequence reaches a set value. If yes, output the last group of kp, ki, and kd as kp', ki', and kd'; otherwise, proceed to the next step;

[0148] (H) Determine whether all the fiber laying processes are completed. If not, input the last set of kp, ki, kd and the i-th pressure difference sequence into the reinforcement learning model with a reward function, which outputs a new set of kp, ki, kd, and sets i=i+1, and then returns to step (C); otherwise, returns to step (A);

[0149] The control instruction generation subsystem is used to generate a control instruction according to the modified value of the heater output power and the modified value of the wire placement terminal motion mechanism path, and then send the control instruction to the wire placement terminal functional mechanism control subsystem and the wire placement terminal motion mechanism control subsystem;

[0150] The control subsystem of the functional mechanism at the end of the wire placement is used to update the heater output power in real time after processing the control instructions;

[0151] The wire placement terminal motion mechanism control subsystem is used to process the control instructions and update the wire placement terminal motion mechanism path in real time.

[0152] Taking the wire laying process twice as an example, the steps of using the system of the present invention to lay wires are described as follows:

[0153] (1) Ribbon installation;

[0154] like Figure 4As shown, after the ribbon is wound on the material roll, the ribbon passes between the driving wheel and the driven wheel, passes through the blade to the pressure roller, and the ribbon is fixed on the bracket 20, which is a vertical frame or a truss fixed on the ground. After that, the connecting piece is connected to the end of the wire laying end movement mechanism;

[0155] When the ribbon passes between the driven wheel and the driving wheel, cylinder b starts to press the ribbon between the driven wheel and the driving wheel;

[0156] When the ribbon reaches the pressing roller, cylinder a starts to push out the pressing rollers on both sides and squeeze with the pressing rollers on the opposite side to achieve the compression of the ribbon;

[0157] (2) First wire laying;

[0158] First, the terminal motion mechanism of the wire laying starts to move along the wire laying path. At the same time, the heater is started to heat the wire. The infrared thermal imager starts to capture the temperature field data of the wire laying area in real time and monitors the temperature of the wire. The pressure sensor obtains the pressure of the wire in real time. The motor drives the driving wheel and the driven wheel to rotate, driving the wire to move forward. In this process, the temperature stabilization control subsystem and the pressure stabilization control subsystem calculate the modification value of the heater output power and the modification value of the path of the terminal motion mechanism of the wire laying according to the real-time data, and send them to the corresponding control subsystem (i.e., the terminal functional mechanism control subsystem or the terminal motion mechanism control subsystem) through the control instruction generation subsystem to adjust the heating power and the wire laying path in real time to ensure that the temperature and pressure of the wire remain within the target range.

[0159] Then, when the laying is about to be completed, the cylinder c is started to drive the blade to shear the ribbon and cut off the excess part. After shearing, the cylinder c is reset;

[0160] Finally, the reserved ribbon between the blade and the pressure roller continues to be laid until the first laying is completed;

[0161] (3) Second wire laying;

[0162] First, the wire placement end motion mechanism moves to the initial position;

[0163] Then, the wire laying end motion mechanism starts to move along the wire laying path. When the laying is about to be completed, the cylinder c is started to drive the blade to shear the ribbon and cut off the excess part. After shearing, the cylinder c is reset.

[0164] Finally, continue laying the reserved ribbon from the blade to the pressure roller until the second laying is completed, turn off the heater, motor, infrared thermal imager, cylinder a, cylinder b, and disconnect the connector from the end of the wire laying end motion mechanism.

[0165] In order to prove that the control system in the patternless mirror fiber placement system of the present invention can accurately control the temperature and pressure, the following experiments are conducted to verify:

[0166] Experimental group 1: using the moldless mirror-image fiber placement system of the present invention, setting the target fiber temperature to 230°C, the initial speed of the fiber placement end motion mechanism to 10 mm / s, the initial output power of the heater to 90 W, and the fiber placement to 300 mm;

[0167] Control group 1: basically the same as experimental group 1, except that there is no control system in the patternless mirror placement system;

[0168] Experimental group 2: using the moldless mirror-image fiber placement system of the present invention, setting the target ribbon temperature to 380°C, the initial speed of the fiber placement end motion mechanism to 50 mm / s, the initial output power of the heater to 210 W, and the fiber placement to 300 mm;

[0169] Control group 2: basically the same as experimental group 2, except that there is no control system in the patternless mirror placement system;

[0170] Experimental group 3: using the moldless mirror-image fiber placement system of the present invention, setting the target ribbon temperature to 500°C, the initial speed of the fiber placement end motion mechanism to 10 mm / s, the initial output power of the heater to 135 W, and the fiber placement to 300 mm;

[0171] Control group 3: basically the same as experimental group 3, except that there is no control system in the patternless mirror placement system;

[0172] Experimental group 4: using the moldless mirror-image wire laying system of the present invention, setting the target wire pressure to 15N, the vertical spacing of the wire laying end motion mechanism to 4mm, and the wire laying distance to 300mm;

[0173] Control group 4: basically the same as experimental group 4, except that there is no control system in the patternless mirror placement system;

[0174] Experimental group 5: using the moldless mirror-image fiber placement system of the present invention, setting the target ribbon pressure to 30N, the vertical spacing of the fiber placement end motion mechanism to 4mm, and the fiber placement to 300mm;

[0175] Control group 5: basically the same as experimental group 5, except that there is no control system in the patternless mirror placement system;

[0176] Experimental group 6: using the moldless mirror-image wire laying system of the present invention, setting the target wire pressure to 45N, the vertical spacing of the wire laying end motion mechanism to 4mm, and the wire laying distance to 300mm;

[0177] Control group 6: basically the same as experimental group 6, except that there is no control system in the patternless mirror placement system;

[0178] The comparison of the wire laying distance-temperature curves of experimental group 1 and control group 1, experimental group 2 and control group 2, and experimental group 3 and control group 3 during the wire laying process are shown in Figure 2. Figure 5 , Figure 6 and Figure 7 As shown, from Figure 5 to Figure 7 It can be seen that compared with control groups 1 to 3, experimental groups 1 to 3 can stably control the actual ribbon temperature within a range close to the target ribbon temperature;

[0179] The comparison of the wire laying distance-pressure curves of experimental group 4 and control group 4, experimental group 5 and control group 5, and experimental group 6 and control group 6 during the wire laying process are shown in Figure 2. Figure 8 , Fig. 9 and Fig.10 As shown, from Figure 8 to Figure 10 It can be seen that compared with control groups 4 to 6, experimental groups 4 to 6 can stably control the actual ribbon pressure within a range close to the target ribbon pressure;

[0180] The above verification process and verification results are sufficient to prove that the control system in the moldless mirror fiber placement system of the present invention can accurately control the temperature and pressure.

Claims

1. A moldless mirror-image wire laying method, It is characterized in that Without using a mold, two ribbons are laid in a mirror-symmetrical manner, and the laying process is repeated multiple times; During the laying process, the actual ribbon temperature is obtained in real time and the temperature difference is calculated in real time. The modified value of the heater output power is calculated in real time according to the temperature difference, and the heater output power is updated in real time. Temperature difference = actual ribbon temperature - target ribbon temperature difference; Modified value of heater output power = kp*×T+ki*×ΣT+kd*×ΔT; Wherein, T is the temperature difference at the current moment of the current wire laying process, ΣT is the sum of all temperature differences of the current wire laying process up to the current moment, ΔT = the temperature difference at the current moment of the current wire laying process - the temperature difference at the previous moment of the current wire laying process; kp*, ki*, kd* are controller parameter combinations that meet the requirements and are found by simulation in a virtual environment and continuous iterative optimization using a reinforcement learning model; During the laying process, the real wire pressure is obtained in real time and the pressure difference is calculated in real time. The modification value of the movement mechanism path at the end of laying is calculated in real time according to the pressure difference, and the movement mechanism path at the end of laying is updated in real time. Pressure difference = actual ribbon pressure - target ribbon pressure; Modified value of the path of the motion mechanism at the end of the wire laying process = kp'×P+ki'×ΣP+kd'×ΔP; Wherein, P is the pressure difference at the current moment of the current wire laying process, ΣP is the sum of all pressure differences of the current wire laying process up to the current moment, ΔP = the pressure difference at the current moment of the current wire laying process - the pressure difference at the previous moment of the current wire laying process; kp', ki', kd' are controller parameter combinations that meet the requirements and are found by simulation in a virtual environment and continuous iterative optimization using a reinforcement learning model.

2. A patternless mirror-image wire laying method according to claim 1, It is characterized in that kp*, ki*, kd* are obtained by the following process: (a) Generate a set of kp, ki, kd; (b) Let i = 1; (c) The same simulation as the actual process is performed in the virtual space, and the i-th wire laying process begins; (d) Let j = 1, let the virtual heater output power = the heater output power in the actual process; (e) inputting the virtual heater output power and the corresponding heating time into the prediction model A, which outputs the predicted ribbon temperature, and calculating the difference between the predicted ribbon temperature and the target ribbon temperature to obtain the jth temperature difference of the i-th temperature difference sequence; Prediction model A is a trained deep learning model. During training, the heater output power and the corresponding heating time are used as the input of the deep learning model, and the ribbon temperature is used as the theoretical output of the deep learning model. The parameters of the deep learning model are continuously adjusted. (f) Determine whether the i-th fiber laying process is completed. If not, calculate the modified value of the virtual heater output power using the following formula, update the virtual heater output power, set j=j+1, and return to step (e); otherwise, proceed to the next step; The modified value of the virtual heater output power = kp×T+ki×ΣT+kd×ΔT; Wherein, T is the jth temperature difference of the i-th temperature difference sequence, ΣT is the sum of all temperature differences of the i-th temperature difference sequence, ΔT = the jth temperature difference of the i-th temperature difference sequence - the j-1th temperature difference of the i-th temperature difference sequence, when j = 1, let ΔT = 0; (g) Score the ith temperature difference sequence and determine whether the score of the ith temperature difference sequence reaches the set value. If yes, output the last group of kp, ki, and kd as kp*, ki*, and kd*; otherwise, proceed to the next step; (h) Determine whether all the wire laying processes are completed. If not, input the last set of kp, ki, kd and the i-th temperature difference sequence into the reinforcement learning model with a reward function, which outputs a new set of kp, ki, kd. After setting i=i+1, return to step (c); otherwise, return to step (a).

3. A patternless mirror-image wire laying method according to claim 2, It is characterized in that The process of obtaining prediction model A is as follows: (i) Establishing a data set; Collect the heater output power, corresponding heating time and actual ribbon temperature in the same historical process as the current process; At the same time, the same simulation as the actual process is performed in the virtual space to obtain the virtual heater output power and the corresponding heating time and virtual ribbon temperature; (ii) Data augmentation: increasing the size of the dataset to obtain a training set; (iii) Establish and train a deep learning model to obtain prediction model A.

4. A patternless mirror-image fiber placement method according to claim 1, It is characterized in that kp', ki', kd' are obtained by the following process: (A) Generate a set of kp, ki, kd; (B) Let i = 1; (C) The same simulation as the actual process is performed in the virtual space, and the i-th wire laying process begins; (D) Let j = 1, let the virtual wire placement end motion mechanism path = the wire placement end motion mechanism path in the actual process; (E) inputting the virtual fiber laying end motion mechanism path into the prediction model B, which outputs the predicted ribbon pressure, and calculating the difference between the predicted ribbon pressure and the target ribbon pressure to obtain the jth pressure difference of the i-th pressure difference sequence; Prediction model B is a trained deep learning model. During training, the path of the motion mechanism at the end of the fiber laying process is used as the input of the deep learning model, and the ribbon pressure is used as the theoretical output of the deep learning model. The parameters of the deep learning model are continuously adjusted. (F) Determine whether the i-th wire laying process is completed. If not, calculate the modification value of the virtual wire laying terminal motion mechanism path using the following formula, update the virtual wire laying terminal motion mechanism path, and set j=j+1, then return to step (E); otherwise, proceed to the next step; The modified value of the virtual wire laying end motion mechanism path = kp×P+ki×ΣP+kd×ΔP; Wherein, P is the jth pressure difference of the i-th pressure difference sequence, ΣP is the sum of all pressure differences of the i-th pressure difference sequence, ΔP = the jth pressure difference of the i-th pressure difference sequence - the j-1th pressure difference of the i-th pressure difference sequence, when j = 1, let ΔP = 0; (G) Score the ith pressure difference sequence and determine whether the score of the ith pressure difference sequence reaches a set value. If yes, output the last group of kp, ki, and kd as kp', ki', and kd'; otherwise, proceed to the next step; (H) Determine whether all the wire laying processes are completed. If not, input the last set of kp, ki, kd and the i-th pressure difference sequence into the reinforcement learning model with a reward function, which outputs a new set of kp, ki, kd. After setting i=i+1, return to step (C); otherwise, return to step (A).

5. A patternless mirror-image fiber placement method according to claim 4, It is characterized in that The acquisition process of prediction model B is as follows: (I) Establishing a data set; Collect the path of the wire laying end motion mechanism and the actual wire pressure in the historical process that is the same as the current process; At the same time, the same simulation as the actual process is performed in the virtual space to obtain the virtual fiber placement end motion mechanism path and the virtual ribbon pressure; (II) Data augmentation: increasing the size of the data set to obtain a training set; (III) Establish and train a deep learning model to obtain prediction model B.

6. A moldless mirror-image wire placement system, It is characterized in that Including hardware part and control system; The hardware part includes a symmetrical left part and a right part, the right part includes a main plate (17), a pressure component, a shearing component, a re-feeding component, a tension component, a heat source component, a connecting piece (3), and a wire laying end movement mechanism, and the pressure component, the shearing component, the re-feeding component, and the tension component are arranged in sequence from front to back along the wire running direction; The pressure component comprises a pressure sensor (1); The heat source component comprises a heater (6) and an infrared thermal imager (7), wherein the heater (6) is used to heat the ribbon (19), and the infrared thermal imager (7) is used to photograph the ribbon laying area in real time to obtain temperature field data of the ribbon (19); The control system includes a temperature stabilization control subsystem, a pressure stabilization control subsystem, a control instruction generation subsystem, a wire placement terminal motion mechanism control subsystem, and a wire placement terminal functional mechanism control subsystem; The infrared thermal imager (7) is used to obtain the real temperature of the ribbon in real time during the ribbon laying process, and send the real temperature of the ribbon to the temperature stabilization control subsystem in real time; The temperature stabilization control subsystem is used to calculate the temperature difference in real time, calculate the modified value of the heater output power in real time according to the temperature difference, and send the modified value of the heater output power to the control instruction generation subsystem in real time; Temperature difference = actual ribbon temperature - target ribbon temperature difference; Modified value of heater output power = kp*×T+ki*×ΣT+kd*×ΔT; Wherein, T is the temperature difference at the current moment of the current wire laying process, ΣT is the sum of all temperature differences of the current wire laying process up to the current moment, ΔT = the temperature difference at the current moment of the current wire laying process - the temperature difference at the previous moment of the current wire laying process; kp*, ki*, kd* are controller parameter combinations that meet the requirements and are found by simulation in a virtual environment and continuous iterative optimization using a reinforcement learning model; The pressure sensor (1) is used to obtain the real ribbon pressure in real time during the fiber laying process, and send the real ribbon pressure to the pressure stabilization control subsystem in real time; The pressure stabilization control subsystem is used to calculate the pressure difference in real time, calculate the modification value of the path of the motion mechanism at the end of the fiber placement in real time according to the pressure difference, and send the modification value of the path of the motion mechanism at the end of the fiber placement to the control instruction generation subsystem in real time; Pressure difference = actual ribbon pressure - target ribbon pressure; Modified value of the path of the motion mechanism at the end of the wire laying process = kp'×P+ki'×ΣP+kd'×ΔP; Wherein, P is the pressure difference at the current moment of the current laying process, ΣP is the sum of all pressure differences of the current laying process up to the current moment, ΔP = the pressure difference at the current moment of the current laying process - the pressure difference at the previous moment of the current laying process; kp', ki', kd' are controller parameter combinations that meet the requirements and are found by simulation in a virtual environment and continuous iterative optimization using a reinforcement learning model; The control instruction generation subsystem is used to generate a control instruction according to the modified value of the heater output power and the modified value of the wire placement terminal motion mechanism path, and then send the control instruction to the wire placement terminal functional mechanism control subsystem and the wire placement terminal motion mechanism control subsystem; The control subsystem of the functional mechanism at the end of the wire placement is used to update the heater output power in real time after processing the control instructions; The wire placement terminal motion mechanism control subsystem is used to process the control instructions and update the wire placement terminal motion mechanism path in real time.

7. The patternless mirror-image wire placement system according to claim 6, It is characterized in that The pressure component further comprises a pressure roller (9), a supporting device, a heat-insulating asbestos board (16) and a cylinder a (2); the central axis of the pressure roller (9) is parallel to the front-rear direction; the pressure roller (9), the supporting device, the heat-insulating asbestos board (16), the pressure sensor (1) and the cylinder a (2) are connected in sequence from left to right; the cylinder a (2) is fixed on the main body plate (17) and is used to push the pressure roller (9) to the left; The shearing component comprises a cylinder c (8) and a blade (14), wherein the cylinder c (8) is used to drive the blade (14) to shear the ribbon (19), and the cylinder c (8) is fixed on the main body plate (17); The re-feeding component comprises a driving wheel (10), a driven wheel (12), a motor (13) and a cylinder b (11); the driving wheel (10) and the driven wheel (12) are arranged vertically and parallel to the left and right directions; the motor (13) is used to drive the driving wheel (10) to rotate; the cylinder b (11) is used to press the driven wheel (12) onto the driving wheel (10); the motor (13) and the cylinder b (11) are fixed on the main body plate (17); The tension component comprises a material reel (4) and a brake (15), wherein the material reel (4) is used to wind the ribbon (19), and the brake (15) is used to provide torque for the material reel (4) to maintain a stable tension force for wire feeding, and the material reel (4) and the brake (15) are both fixed on the main plate (17); The heat source component also includes a support plate (5), a heater (6) is fixed on the main plate (17), and an infrared thermal imager (7) is fixed on the main plate (17) through the support plate (5); The connecting piece (3) is fixed on the main plate (17) and connected to the end of the wire placement end movement mechanism.

Images