Infrared heating control system, method, and fiber placement machine

Abstract

The application discloses an infrared heating control system of a fiber laying machine, which comprises an acquisition unit, a control unit and an adjusting unit. The control unit is connected with the fiber laying machine and receives current operation data of the fiber laying machine. The output end of the control unit is connected with the adjusting unit, and the output end of the adjusting unit is connected with the input end of the control unit, so that the adjusting unit feeds back output temperature data to the control unit. The acquisition unit is connected with the control unit and acquires current temperature data of the fiber laying machine. The control unit is used for receiving and processing the current temperature data and the current operation data to obtain set temperature data, and generating real-time control instructions according to the set temperature data and the output temperature data. The adjusting unit is connected with an infrared heating element, and the adjusting unit is used for adjusting current parameters of the infrared heating element according to the real-time control instructions. The control unit obtains real-time control instructions by continuously receiving and processing the transmitted data, and adjusts the parameters of the infrared heating element through the adjusting unit to improve the heating effect.

Description

Technical Field

[0001] This application relates to the field of composite material molding and processing technology, and in particular to an infrared heating control system and method for a fiber placement machine, as well as a fiber placement machine. Background Technology

[0002] In the molding and processing of composite materials, a common scenario is the use of automated layup equipment in aerospace equipment manufacturing to lay composite materials onto target equipment according to predetermined standards and requirements. Some composite materials require cross-linking, polycondensation, and chemical reactions under heat to solidify and form. For example, prepreg narrow strips commonly used in automated fiber placement equipment are made by impregnating unidirectional fibers with a resin matrix to create a composition of resin matrix and reinforcement, i.e., prepreg tape is slit and rewound. Prepreg narrow strips are normally stored in a low-temperature environment of minus ten degrees Celsius. When needed for layup, they are usually taken out 24 hours in advance and thawed in a clean environment at approximately 20 degrees Celsius. After being loaded into the yarn box of the fiber placement machine, the yarn box and yarn feed lines also need to maintain a suitable ambient temperature. If the temperature is too high, the filaments will undergo a cross-linking reaction, causing the filaments to stick to the yarn feeding device and yarn feed lines, leading to difficulties in yarn feeding or yarn blockage, resulting in layup process failures, seriously affecting the working efficiency of the fiber placement machine and product quality. When the fiber lays the fiber, the temperature of the laying surface must reach the optimal temperature for crosslinking of the prepreg to ensure that the resin of the previous layer and the current layer of the fiber bundle are fully bonded. Typically, the temperature of low-temperature curing prepreg is about 80°C, the temperature of medium-temperature curing prepreg is about 120°C, and the temperature of high-temperature curing prepreg is equal to or greater than 180°C. Temperature control directly affects the laying quality and efficiency, so it is particularly important to control the temperature of the prepreg in the fiber lay system. Summary of the Invention

[0003] The main purpose of this application is to provide an infrared heating control system and method for a filament placing machine, as well as a filament placing machine, in order to solve the technical problem of poor infrared heating effect in existing filament placing machine equipment.

[0004] To achieve the above objectives, this application provides an infrared heating control system for a fiber placement machine. The fiber placement machine is used for laying composite materials, and the fiber placement machine includes an infrared heating element. The infrared heating control system includes a data acquisition unit, a control unit, and an adjustment unit.

[0005] The control unit is connected to the filament placement machine and is used to receive the current operating data of the filament placement machine;

[0006] The output terminal of the control unit is connected to the adjustment unit, and the output terminal of the adjustment unit is connected to the input terminal of the control unit, so that the adjustment unit can feed back output temperature data to the control unit;

[0007] The acquisition unit is connected to the input terminal of the control unit, and the acquisition unit is used to acquire the current temperature data of the filament laying machine;

[0008] The control unit is used to receive and process the current temperature data and the current operating data to obtain the set temperature data, and to generate real-time control commands based on the set temperature data and the output temperature data;

[0009] The adjustment unit is connected to the infrared heating element, and the adjustment unit is used to adjust the current parameters of the infrared heating element according to the real-time control command.

[0010] Optionally, the control unit includes a first analog input module, a second analog input module, an analog output module, and a control processing module, wherein the first analog input module, the second analog input module, and the analog output module are respectively connected to the control processing module.

[0011] Optionally, the acquisition unit includes a first sensing module, a second sensing module, and a third sensing module.

[0012] The first sensing module and the second sensing module are respectively connected to the first analog input module, and the third sensing module is connected to the second analog input module.

[0013] The first sensing module is used to collect the ambient temperature of the fiber placement area of ​​the fiber placement machine, the second sensing module is used to collect the heating temperature of the infrared heating element, and the third sensing module is used to collect the actual temperature of the composite material layup.

[0014] Optionally, the adjustment unit includes an execution module and a measurement module.

[0015] The input terminal of the execution module is connected to the output terminal of the analog output module, and the output terminal of the execution module is connected to the infrared heating element;

[0016] The measurement module is connected to the first analog input module, and the measurement module is used to feed back the output temperature data to the first analog input module.

[0017] On the other hand, this application also provides a fiber placement machine for laying composite materials, the fiber placement machine including an infrared heating element, and the fiber placement machine including the fiber placement machine infrared heating control system as described above.

[0018] Furthermore, this application also provides an infrared heating control method, which is used in the infrared heating control system of the filament laying machine as described above, and includes the following steps:

[0019] The current temperature data and the current operating data are obtained through the acquisition unit and the fiber placement machine;

[0020] Based on the current temperature data and the current operating data, obtain the set temperature data for infrared heating;

[0021] Based on the output temperature data and the set temperature data, generate real-time control commands;

[0022] The real-time control command is output to the adjustment unit so that the adjustment unit adjusts the current parameters of the infrared heating element of the filament laying machine according to the real-time control command.

[0023] Optionally, obtaining the current temperature data and current operating data of the fiber placement machine includes:

[0024] Determine whether the fiber placement speed of the fiber placement machine is zero;

[0025] If the determination result is negative, the current operating data and the current temperature data are obtained; wherein, the current operating data includes the placement speed of the filament placer, and the current temperature data includes the heating temperature, the ambient temperature, and the actual temperature of the layup layer;

[0026] If the judgment result is yes, stop the operation of the infrared heating element of the filament laying machine.

[0027] Optionally, the set temperature data includes a set power, and obtaining the set temperature data for infrared heating based on the current temperature data and the current operating data includes:

[0028] The set power of the infrared heating element of the filament laying machine is obtained according to the following relationship;

[0029] P 设定 =K·v·(T) 设定 -T 实际 ),

[0030] Among them, P 设定 The value represents the set power of the infrared heating element of the fiber placement machine, K represents the proportional coefficient, v represents the placement speed, and T represents the setting power of the infrared heating element of the fiber placement machine. 设定 Indicates the set temperature for the layup, T 实际 This indicates the actual temperature of the ply.

[0031] Optionally, obtaining the real-time control command for infrared heating based on the output temperature data and the set temperature data includes:

[0032] Calculate the deviation between the output temperature data and the set temperature data;

[0033] The deviation is used as the input to the PID control algorithm, and the control quantity corresponding to the deviation is obtained according to the following relationship:

[0034]

[0035] Where u(t) is the control variable, e(t) is the deviation, and K p For the proportional gain of the control law, T i Let T be the integral time constant of the control law. d Let be the differential time constant of the control law;

[0036] The real-time control command is generated based on the control quantity corresponding to the deviation.

[0037] Optionally, after outputting the real-time control command to the adjustment unit so that the adjustment unit adjusts the current parameters of the infrared heating element of the filament laying machine according to the real-time control command, the method further includes:

[0038] Return to the step of obtaining the current temperature data and the current operating data.

[0039] The infrared heating control system for a filament placement machine provided in this application includes a data acquisition unit, a control unit, and an adjustment unit. The control unit is connected to the filament placement machine and is used to receive the current operating data of the filament placement machine. The output terminal of the control unit is connected to the adjustment unit, and the output terminal of the adjustment unit is connected to the input terminal of the control unit, so that the adjustment unit can feed back output temperature data to the control unit. The data acquisition unit is connected to the input terminal of the control unit and is used to acquire the current temperature data of the filament placement machine. The control unit is used to receive and process the current temperature data and the current operating data to obtain set temperature data, and generate real-time control commands based on the set temperature data and the output temperature data. The adjustment unit is connected to the infrared heating element and is used to adjust the current parameters of the infrared heating element according to the real-time control commands. By connecting the control unit to the filament placement machine, the data acquisition unit, and the adjustment unit, the current temperature data, operating data, and output temperature data of the filament placement machine can be received, and real-time control commands can be calculated and obtained based on these data and actual needs to control the temperature of the infrared heating element, thereby improving the control effect of infrared heating during the filament placement process. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the structure of an embodiment of the infrared heating control system for a filament laying machine according to this application;

[0042] Figure 2 This is a schematic diagram of the structure of an embodiment of the infrared heating control system for a filament laying machine according to this application;

[0043] Figure 3 This is a schematic diagram of the structure of an embodiment of the infrared heating control system for a filament laying machine according to this application;

[0044] Figure 4 This is a schematic flowchart of one embodiment of the infrared heating control method of this application;

[0045] Figure 5 This illustrates the positional relationship between the infrared heating element and the ply in one embodiment of the infrared heating control method of this application.

[0046] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0047] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0048] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0049] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0050] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0051] Current temperature control methods for prepreg placement equipment primarily rely on empirical methods and mathematical modeling of thermal radiation. Empirical methods, which summarize the relationship between the heating power of infrared heating elements and various parameters during placement based on extensive experimental data, lack theoretical basis, have limited experimental data, and restrict application scenarios. Mathematical modeling of thermal radiation, on the other hand, establishes thermal radiation equations and determines the coefficients to represent the relationship between the power of infrared heating elements and various parameters during placement. However, this method does not consider the impact of the response time of the infrared heating element wavelength during high-speed placement; that is, the radiation from the infrared heating element may only heat the surface of the prepreg and fail to penetrate the narrow bands within the prepreg. Generally, the reaction time from the introduction of current into the filament of the infrared heating element to the normal generation of thermal radiation exceeds one minute. The heating power determined according to the thermal radiation equation may not meet the heating requirements of high-speed prepreg placement. Furthermore, during the placement process, it is necessary to continuously adjust the power of the infrared heating elements in real time according to the ideal temperature of each layer, increasing the difficulty of placement.

[0052] Based on the problems in the prior art, this application proposes an infrared heating control system and method for a filament laying machine, as well as a filament laying machine, to realize that the infrared heating element is controlled to heat according to real-time control commands during the filament laying process, thereby achieving a better heating effect.

[0053] Figure 1The diagram illustrates the structure of a basic embodiment of the infrared heating control system for a filament placement machine according to this application. The control system includes: a data acquisition unit, a control unit, and an adjustment unit. The control unit is connected to the filament placement machine and is used to receive the current operating data of the machine. The output terminal of the control unit is connected to the adjustment unit, and the output terminal of the adjustment unit is connected to the input terminal of the control unit, enabling the adjustment unit to feed back output temperature data to the control unit. The data acquisition unit is connected to the input terminal of the control unit and is used to acquire the current temperature data of the filament placement machine. The control unit is used to receive and process the current temperature data and the current operating data to obtain set temperature data, and to generate real-time control commands based on the set temperature data and the output temperature data. The adjustment unit is connected to the infrared heating element of the filament placement machine and is used to adjust the current parameters of the infrared heating element according to the real-time control commands.

[0054] It should be noted that the infrared heating control system in the basic embodiment of this application does not include an infrared heating element. Infrared heating elements are generally provided in the yarn laying machine. When applying the infrared heating control system of this application embodiment, the adjustment unit can be connected to the infrared heating element. In particular, in some other embodiments, for the sake of completeness of the technical solution, the infrared heating system of this application may also include an infrared heating element (such as...). Figure 1 , Figure 2 As shown, the connection method and function of the infrared heating element in this system are consistent with those described in the basic embodiment above. The main inventive point of this application lies in controlling the output parameters such as current, voltage, and power, which are therefore omitted in the infrared heating control system of the above embodiment, but this does not mean that this embodiment is to be understood in a way that limits the scope of protection.

[0055] In this embodiment, the fiber placement machine is a machine used in the manufacturing process of composite material rotating components in the aerospace industry. It can automatically perform fiber placement of composite materials according to a predetermined planning model and trajectory. With current technology, fiber placement machines have achieved efficient fiber placement operations by establishing an automatic fiber placement trajectory planning model based on a general mathematical model of a rotating body and calculating the coverage between the center lines of adjacent fiber placement trajectories using geodesics. The composite material in the placement portion of the fiber placement machine needs to be heated to better fuse the layers; therefore, fiber placement machines are generally equipped with heating components, among which infrared heating elements, such as infrared radiation heaters, are commonly used. Therefore, in the embodiments of this application, the fiber placement machines mentioned all include infrared heating elements and are understood as implementation carriers for the infrared heating control system and infrared heating control method embodiments in this application.

[0056] The data acquisition unit is used to acquire the current temperature data of the yarn laying machine. It can be a thermistor. Alternatively, to maintain continuous transmission of the current temperature data, the acquisition unit can also be a quasi-digital sensor that outputs a periodic signal. The control unit is used to receive and process data and issue real-time control commands. It has functions such as signal transmission and reception, data processing and storage, and can be implemented as a PLC (Programmable Logic Controller). The regulating unit is used to receive and execute the real-time control commands from the control unit and feed back the output temperature data to the control unit. In the embodiments of this application, it can consist of relays, power regulators, etc., for controlling circuit current, voltage, and power changes, current transformers for current detection, and thermocouples for temperature detection.

[0057] Specifically, when the system of this embodiment is applied to a filament placing machine, the acquisition unit can collect the current temperature data during the filament placing process in real time and transmit it to the control unit. The control unit is connected to the filament placing machine and can read the current operating data of the filament placing machine. By combining the current temperature data and the current operating data with the quantitative data of actual needs (the quantitative data can be pre-stored in the control unit), the set temperature data that needs to be output during the filament placing process can be calculated. The mathematical relationship between the current temperature data, the current operating data, the quantitative data, and the set temperature data is stored in the control unit in the form of an equation for calculation. After receiving the output temperature data fed back by the adjustment unit, the control unit processes the set temperature data and the output temperature data to generate real-time control commands and transmits them to the adjustment unit for execution, so as to continuously determine and adjust the heating amount during the filament placing process to achieve real-time and accurate temperature control.

[0058] Specifically, the acquisition of current temperature data and current operating data is real-time and continuous, thus forming two sets of dynamic data. Correspondingly, the set temperature data and output temperature data are also dynamic data. The control commands generated from this are real-time control commands. It can be understood that the generated real-time control commands are the result of integrating countless control signals within a unit of time. The smaller the unit of time, the better and more precise the control effect of the real-time control commands.

[0059] As one implementation method, in order to enable the control unit to receive and process current temperature data, current operating data, and output temperature data, see [link to relevant documentation]. Figure 2 The control unit includes an analog output module A1, a first analog input module A2, a second analog input module A3, and a control processing module CMD. The first analog input module A2, the second analog input module A3, and the analog output module A1 are respectively connected to the control processing module CMD.

[0060] In some implementations, the control processing module (CMD) can read data such as the placement mode M and heating trajectory length L of the filament placer, and process this data to achieve full-process infrared heating control. Furthermore, the control processing module CMD is connected to the heating control switch K, and the infrared heating system is turned on and off via the heating control switch K.

[0061] In this embodiment, the control processing module (CMD) is a key module for receiving and processing data, and can be implemented using the FB function block with data storage function in the PLC integrated with the CNC system. The first analog input module A2 and the second analog input module A3 are used to convert analog signals such as electrical signals and temperature signals into unified digital signals. The analog output module A1 is used to convert the processed digital signals back into electrical signals for output. That is, the analog output module A1, the first analog input module A2, and the second analog input module A3 are all implemented as digital-to-analog conversion functions in this embodiment, and are typically part of an integrated PLC. Through the first analog input module A2 and the second analog input module A3, non-electrical physical quantities such as temperature and power received by the control unit are converted from digital to analog into unified standard electrical quantities. The analog output module A1 converts the standard electrical quantities back into non-electrical physical quantities, so that the control processing module CMD can perform digital processing and issue control command signals. Furthermore, the control processing module CMD is also connected to the yarn laying machine, specifically to the CNC system of the yarn laying machine, and directly reads the current operating data from the data system. This connection is conventional prior art and will not be described in detail here.

[0062] In some implementations, the first analog input module A2 is a 4-20mA current-type A / D converter with a resolution of 13 bits, and may also include a thermistor RTD / thermocouple TC for measuring temperature; the second analog input module A3 is a thermistor RTD / thermocouple TC with a resolution of 15 bits; and the analog output module A1 is a 4-20mA current-type D / A converter with a resolution of 13 bits.

[0063] As one implementation method, to obtain data on different variables affecting the set temperature data, see [link to relevant documentation]. Figure 2 The acquisition unit includes a first sensing module R1, a second sensing module R2, and a third sensing module R3. The first sensing module R1 and the second sensing module R2 are respectively connected to the first analog input module A3, and the third sensing module R3 is connected to the second analog input module A3. The first sensing module R1 is used to acquire the ambient temperature of the fiber placement area of ​​the fiber placement machine, the second sensing module R2 is used to acquire the heating temperature of the infrared heating element, and the third sensing module R3 is used to acquire the actual layup temperature of the composite material.

[0064] In this embodiment, the first sensing module R1, the second sensing module R2, and the third sensing module R3 are used to detect different current temperature data, including ambient temperature, heating temperature, and actual layup temperature. The acquisition units can all be temperature sensors. It should be noted that the temperature data detected and transmitted by the first sensing module R1, the second sensing module R2, and the third sensing module R3 are all actual values ​​under the current operating conditions. By collecting temperature data of different attributes from multiple sensing modules and transmitting it to the control unit, the control unit can continuously and in real-time acquire the current temperature data and perform further processing.

[0065] In some embodiments, the first sensing module R1 is an ambient temperature sensor, installed in the middle of the filament placement machine, at a distance of more than 1.5m away from the infrared heating element and cooling device, unaffected by radiation and convection from the heating and cooling devices, and capable of detecting the ambient temperature at the filament placement machine site; the second sensing module R2 is installed near the infrared heating element to detect its temperature; the third sensing module R3 is installed at a fixed position on the filament placement head to detect the temperature of the layup surface. The first sensing module R1 and the second sensing module R2 are connected using a two-wire system, while the third sensing module R3 is connected using a three-wire system. Through these embodiments, the accuracy and efficiency of data acquisition by the acquisition unit can be improved.

[0066] In one implementation, the adjustment unit includes an execution module E and a measurement module D, see [link to relevant documentation]. Figure 2 The input terminal of the execution module E is connected to the output terminal of the analog output module, and the output terminal of the execution module E is connected to the infrared heating element; the measurement module D is connected to the first analog input module, and the measurement module D is used to feed back the output temperature data to the first analog input module.

[0067] In this embodiment, the execution module E is used to adjust the circuit current and voltage according to the real-time control command electrical signal issued by the control unit to directly drive the controlled object and change the output. Specifically, it may include a solid-state relay or a power regulator. The measurement module D is used to detect the controlled quantity (which may be current, voltage, or power) and convert it into the required electrical signal. The measurement module D is connected to the control unit, forming a closed-loop feedback loop between the adjustment unit and the control unit. Taking the circuit power as an example, when the control unit receives the preset output power P from the CNC system... 设 After issuing a control command to the regulating unit, the execution module E of the regulating unit adjusts the circuit power according to the command, while the measurement module D detects the actual power P in the circuit. 实 And feedback is sent to the control unit, which then processes the data according to P. 设 With P 实The deviation is processed to obtain a new real-time control command, so that the power output to the infrared heating element is close to P. 设 And it tends to stabilize. Furthermore, the connection between the measurement module D and the control unit, and the feedback of current output data, is achieved through the first analog input module A2 in the aforementioned embodiment. The electrical signal output by the measurement module D is converted from analog to digital by the first analog input module A2 so that the control unit can perform digital processing. By feeding back the current output data to the control unit through the measurement module D in the adjustment unit, a closed-loop circuit is formed between the control unit and the adjustment unit, thereby enabling the control unit to process the feedback data and issue continuous real-time control commands.

[0068] In some implementations, the execution module E can be a solid-state relay, with its output connected to an infrared heating element (IR), and the measurement module D can be a current transformer. Specifically, connecting a current transformer to the solid-state relay circuit allows for direct acquisition of the current input to the infrared heating element, resulting in more accurate data transmission of the current output to the control unit.

[0069] Figure 3 A filament placement machine is shown, including an infrared heating element and an infrared heating control system as described in the foregoing embodiments. The output of the infrared heating control system is connected to the infrared heating element and is used to control the infrared heating element.

[0070] Understandable Figure 3 The description only provides a logical explanation of the filament placing machine that uses the aforementioned infrared heating control system. The specific structure and positional relationship of the filament placing machine are not the inventive points of this application embodiment, and therefore will not be specifically shown.

[0071] In some implementations, short-wave infrared heating elements are selected, and the power is estimated and selected based on the composite material requiring high temperatures. Taking an 8-bundle prepreg with a narrow strip width of 6.35mm as an example, the theoretical bundle width is 50mm, but the actual heating width should be greater than 50mm. When selecting the actual heater, 10-15mm is added to each side, resulting in a heating length of 70-80mm. An approximately 800W short-wave infrared heating element can be selected. Short-wave heaters are characterized by fast response time; the thermal radiation response time from cold start to rated power is approximately 1 second, and the starting current is greater than 12 times the rated current. Short-wave infrared heating elements can respond quickly to power changes, thereby reducing the time to reach the predetermined temperature and improving the heating efficiency during the fiber placement process.

[0072] By applying the infrared heating control system of the foregoing embodiments to the filament placement machine of this embodiment, the technical effects of the foregoing embodiments can be realized on existing filament placement machine equipment.

[0073] Figure 4An infrared heating control method is shown, which is used in the infrared heating control system of the yarn laying machine in the foregoing embodiments, and includes the following steps:

[0074] S1, the current temperature data and the current operating data are obtained through the acquisition unit and the fiber placement machine.

[0075] S2, based on the current temperature data and the current operating data, obtain the set temperature data for infrared heating.

[0076] S3, generate real-time control commands based on the output temperature data and the set temperature data.

[0077] S4, output the real-time control command to the adjustment unit so that the adjustment unit adjusts the current parameters of the infrared heating element of the filament laying machine according to the real-time control command.

[0078] In this embodiment, the steps of the infrared heating control method correspond one-to-one with the steps of the control processing module CMD receiving, processing data and obtaining real-time control commands in the infrared heating control system of the aforementioned basic embodiment. The specific implementation method and the technical effects that can be achieved can be found in the aforementioned basic embodiment, and will not be repeated here.

[0079] As one implementation, step S1 of acquiring the current temperature data and current operating data of the fiber placement machine includes:

[0080] S11, determine whether the laying speed of the fiber laying machine is zero.

[0081] S12, if the determination result is negative, obtain the current operating data and the current temperature data; wherein, the current operating data includes the laying speed of the filament laying machine, and the current temperature data includes the heating temperature, the ambient temperature, and the actual layup temperature.

[0082] S13, if the judgment result is yes, stop the operation of the infrared heating element of the filament laying machine.

[0083] In this embodiment, determining whether the placement speed of the filament placer is zero is used as the condition for obtaining the current temperature and current operating data of the filament placer. When the placement speed of the filament placer is zero, it may be in a state of low infrared heating demand, such as being stopped or in standby mode. If continuous infrared heating is maintained, it may affect the placement effect in some placement areas. When the placement speed of the filament placer is not zero, it means that it is working, and the current operating data and current temperature data need to be obtained for subsequent processing. By setting the condition for obtaining data, energy can be saved and machine wear can be reduced, and the automation and working efficiency of infrared heating control can also be improved.

[0084] As one implementation, step S2, which involves obtaining the set temperature data for infrared heating based on the current temperature data and the current operating data, includes:

[0085] S21, the set power of the infrared heating element of the filament laying machine is obtained according to the following relationship;

[0086] P 设定 =K·v·(T) 设定 -T 实际 ),

[0087] Among them, P 设定 The value represents the set power of the infrared heating element of the fiber placement machine, K represents the proportional coefficient, v represents the placement speed, and T represents the setting power of the infrared heating element of the fiber placement machine. 设定 Indicates the set temperature for the layup, T 实际 This indicates the actual temperature of the ply.

[0088] The above formula will be further explained below in conjunction with specific application scenarios.

[0089] In some implementations, the composite material layup laid by the fiber placer is a narrow strip of prepreg. Figure 5 The relationship between the infrared heating element and the prepreg layer is illustrated. The infrared heating element is an infrared lamp, consisting of a tungsten filament, a quartz tube, and a gold-plated reflective film with a heat-insulating layer. The filament is wound into a spiral cylinder, and the electrical connector is fixed with ceramic material. Since the rated operating wavelength of the infrared lamp is short-wave, the filament surface is considered a diffuse surface. The gold-plated reflective film is coated on the upper half of the quartz tube, and the entire reflective film layer can be considered as a specular reflection. The thermal radiation performance of the filament surface approximates that of a blackbody surface as defined in the Stefan-Boltzmann law. When the infrared lamp and the prepreg laying environment are in thermal equilibrium during layup, the heat source relationship is as follows:

[0090]

[0091] Where P is the infrared lamp power, S is the effective radiant area of ​​the filament, E is the filament radiation intensity, ε is the filament emissivity, σ is the Boltzmann constant, T is the filament temperature, ζ is the filament helical packing density coefficient, R is the filament radius, and L is the filament length.

[0092] The heat transfer mechanism of infrared heating elements for prepreg surfaces is primarily thermal radiation. Although thermal conduction and convection also occur, the heat energy transferred through these two methods is negligible for engineering applications of prepreg surface heating. Since the infrared lamps are mounted on fixed supports, their relative positions to the prepreg surface remain constant during installation, and thermal radiation occurs only within a limited area. Therefore, the thermal radiation energy Q absorbed by the prepreg consists of two parts: one part is the energy Q directly radiated from the filament to the prepreg surface.直 The other part is the energy Q indirectly reflected to the surface of the prepreg through the reflective film coating. 间 If the surface of the prepreg is considered as a gray body with a constant absorptivity α, then the effective thermal radiation energy absorbed by the surface of the prepreg per unit time is:

[0093] Q=α(Q 直 +Q 间 )=α(E 灯 S 灯 X 1.3 +ρE 灯 S 灯 X 1.2 X 2.3 )=α(X 1.3 +ρX 1.2 X 2.3 )P

[0094] Where ρ is the reflectivity of the reflective coating, and X 1.3 X is the angle coefficient between the filament surface and the prepreg surface, i.e., the proportion of energy directly radiated from the filament surface to the prepreg surface. 1.2 X is the angular coefficient of radiation from the filament surface to the reflective film surface, i.e., the proportion of energy radiated from the filament surface to the reflective film coating surface. 2.3 It is the angle coefficient of the reflective coating reflected to the surface of the prepreg, that is, the proportion of energy reflected by the reflective coating to the surface of the prepreg.

[0095] During automatic laying, the infrared lamps move at a fixed height on the prepreg surface at a given laying speed. The prepreg surface receives the radiation energy from the infrared lamps. The relationship between the temperature change of the prepreg surface and the thermal radiation energy received from the infrared lamps is as follows:

[0096]

[0097] Where C is the specific heat capacity of the prepreg, M is the mass of the prepreg on the effective radiating surface, ΔT is the temperature rise of the prepreg surface, L is the length of the effective radiating surface along the layup trajectory, and V is the layup speed of the fiber placement machine cutter center point along the layup trajectory. At the optimal temperature that meets the process requirements of the prepreg layup surface, the relationship between the infrared lamp power and the layup speed is:

[0098]

[0099] Since the filament surface is considered a diffuse surface, its normal operating condition can be regarded as equal-intensity radiation. The angle factor is only related to the size and shape of the filament and prepreg surfaces, as well as the installation position of the infrared lamp bracket. The installation position of the infrared lamp bracket takes into account the overall layout of the filament layup head, and the optimal installation position can be selected through simulation and experimentation to obtain the highest possible radiation intensity and the best temperature uniformity. Because the relative position of the heating infrared lamp and the prepreg layup surface on the filament layup head is constant, the effective heating area S of the prepreg layup layer remains unchanged, and the angle factor X 1.3 X 1.2 X 2.3 Since the constant is constant, the mathematical formula for controlling the heating infrared lamp is:

[0100] P = KVΔT

[0101] in, In the expression for the value of K, all values ​​are constants, so K is a constant.

[0102] According to the formula P = KVΔT, the set power of the infrared lamp is directly proportional to the laying speed and the temperature difference required to heat the prepreg. K is a constant, which is related to the specific heat capacity, mass, absorptivity of the prepreg, the effective radiating surface area of ​​the heating lamp, and the installation position of the lamp holder. When the ambient temperature changes, the surface temperature of the prepreg will change accordingly. Similarly, when using different grades of prepreg, the viscosity of the prepreg surface will also change. In these cases, the value of K needs to be corrected.

[0103] In this embodiment, the infrared heating control system acquires the heating temperature of the infrared heating unit, the ambient temperature, and the actual layup temperature through its acquisition unit. This data is then transmitted to the control processing module (CMD) via the first analog input module A2 and the second analog input module A3. Simultaneously, the control processing module can directly read the layup speed of the filament placer, allowing the CMD to process the received data. Detecting the infrared lamp temperature ensures that the lamp operates in the short-wave mid-band under rated conditions; otherwise, it can lead to shorter filament life and slow cold-start response. Detecting the ambient temperature determines whether the temperature difference between the ambient temperature and the layup surface temperature exceeds 2°C; if it does, the K value needs correction. Detecting the layup surface temperature calculates the electrical power output control based on the prepreg's required layup temperature.

[0104] Specifically, taking actual operation as an example, the control processing module CMD reads the ambient temperature every 0.5 seconds or continuously. When the filament placer is in operation, it directly reads the combined speed of the tool center through the CNC system, i.e., the real-time placement speed of the filament placer. Then, it reads the required power command setting value from the set parameter set DB block (the DB module is a data block in the PLC and is used for data transmission within the PLC), and converts this value into the range input corresponding to the analog output module A1. The analog output module A1 outputs a 4-20mA drive current according to the range, driving the adjustment unit to adjust (e.g., change the conduction angle of the power regulator PR), thereby controlling the current flowing through the infrared heating element and changing the magnitude of the infrared radiation power. The adjustment unit is connected to the measurement module D (e.g., a current transformer), which can directly obtain the magnitude of the current flowing through the infrared heating element and directly feed it back to the control processing module CMD.

[0105] In some implementations, the ambient temperature data ranges from 0 to 35°C, the ambient temperature step change range is 1°C, the layup speed ranges from 0.01 to 1.2 times the maximum layup speed of the fiber layup machine, and the number of segments is set according to the requirements of the composite material layup process parameters; in addition, the power of the infrared heating element can be divided into 256 equal parts from 0 to the rated power, corresponding to an analog output current of 4-20mA from the analog output module A1.

[0106] In some implementations, in particular, the relationship between the laying speed and the laying temperature (which can be converted to and from the set power using the aforementioned formula) can be found through a data fitting algorithm, thereby enabling the control processing module (CMD) to generate real-time control commands.

[0107] In one implementation, the set temperature data includes a set power. Specifically, the set temperature data is selected as comparison data for the output temperature data; that is, the data attributes of the set temperature data are consistent with the data attributes of the output temperature data. The data attributes of the set temperature data and the output temperature data may include power, current, and voltage, etc. In this embodiment, the set power is used as the set temperature data, which can be calculated according to the aforementioned formula. The data is obtained without conversion, making it convenient to compare with the feedback output temperature data (output power) in subsequent steps for further adjustments.

[0108] The above analysis shows that the embodiments of this application can calculate and adjust the required set power based on the real-time data collected by the acquisition unit of the filament placement machine's placement speed and the actual temperature of the layer. The power output to the infrared heating element is controlled by the real-time control command of the control processing module CMD, thereby achieving a better layer state by controlling the placement temperature in real time, thus improving the placement effect of the filament placement machine.

[0109] As one implementation, step S3, which involves obtaining a real-time control command for infrared heating based on the output temperature data and the set temperature data, includes:

[0110] S31, calculate the deviation between the output temperature data and the set temperature data;

[0111] S32, the deviation is used as the input to the PID control algorithm, and the control quantity corresponding to the deviation is obtained according to the following relationship:

[0112]

[0113] Where u(t) is the control variable, e(t) is the deviation, and K p For the proportional gain of the control law, T i Let T be the integral time constant of the control law. d Let be the differential time constant of the control law;

[0114] S33, Generate the real-time control command based on the control quantity corresponding to the deviation.

[0115] As can be seen from the foregoing embodiments, a closed-loop circuit is formed between the control unit and the adjustment unit in the infrared heating control system. The adjustment unit can feed back the current, voltage, or power output to the infrared heating element to the control unit, thereby enabling the control unit to generate real-time control commands based on the PID control algorithm. These real-time control commands may include the current, voltage, or power values ​​output to the infrared heating unit.

[0116] It should be noted that outputting control quantities based on PID control algorithms is a common technique in the field of automation, and the principles and applications of this control algorithm will not be explained in detail here.

[0117] As one implementation, after step 4, in which the real-time control command is output to the adjustment unit so that the adjustment unit adjusts the current parameters of the infrared heating element of the filament laying machine according to the real-time control command, the method further includes:

[0118] S5, return to the step of obtaining the current temperature data and the current operating data.

[0119] In this embodiment, after the infrared heating element receives the real-time control command to adjust the parameters, its temperature may not be constant and may fluctuate, and there may be a need to adjust the temperature. Therefore, the step of obtaining the current temperature data and the current running data is returned to form a cycle in time and issue dynamic and continuous real-time control commands, thereby obtaining a better heating effect.

[0120] The above description is merely an optional embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the inventive concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. An infrared heating control system for a fiber placement machine, the fiber placement machine being used for laying composite materials, the fiber placement machine including an infrared heating element, characterized in that, The infrared heating control system includes a data acquisition unit, a control unit, and an adjustment unit; The control unit is connected to the filament placement machine and is used to receive the current operating data of the filament placement machine; The output terminal of the control unit is connected to the adjustment unit, and the output terminal of the adjustment unit is connected to the input terminal of the control unit, so that the adjustment unit can feed back output temperature data to the control unit; The acquisition unit is connected to the input terminal of the control unit, and the acquisition unit is used to acquire the current temperature data of the filament laying machine; The control unit is used to receive and process the current temperature data and the current operating data to obtain the set temperature data, and generate real-time control commands based on the set temperature data and the output temperature data; the control unit includes a first analog input module, a second analog input module, an analog output module and a control processing module, wherein the first analog input module, the second analog input module and the analog output module are respectively connected to the control processing module; The adjustment unit is connected to the infrared heating element, and the adjustment unit is used to adjust the current parameters of the infrared heating element according to the real-time control command; The acquisition unit includes a first sensing module, a second sensing module, and a third sensing module. The first sensing module and the second sensing module are respectively connected to the first analog input module, and the third sensing module is connected to the second analog input module. The first sensing module is used to acquire the ambient temperature of the fiber placement area of ​​the fiber placement machine, the second sensing module is used to acquire the heating temperature of the infrared heating element, and the third sensing module is used to acquire the actual layup temperature of the composite material. By acquiring temperature data of different properties through multiple sensing modules and transmitting it to the control unit, the control unit can continuously acquire the current temperature data in real time and perform further processing.

2. The infrared heating control system for the filament laying machine according to claim 1, characterized in that, The adjustment unit includes an execution module and a measurement module. The input terminal of the execution module is connected to the output terminal of the analog output module, and the output terminal of the execution module is connected to the infrared heating element; The measurement module is connected to the first analog input module, and the measurement module is used to feed back the output temperature data to the first analog input module.

3. A fiber placement machine, said fiber placement machine being used for laying composite materials, said fiber placement machine including an infrared heating element, characterized in that, The filament placement machine includes the infrared heating control system for filament placement machines as described in claim 1 or 2.

4. An infrared heating control method, wherein the infrared heating control method is used in the infrared heating control system of the filament laying machine as described in claim 1 or 2, characterized in that, Includes the following steps: The current temperature data and the current operating data are obtained through the acquisition unit and the fiber placement machine; Based on the current temperature data and the current operating data, obtain the set temperature data for infrared heating; Based on the output temperature data and the set temperature data, generate real-time control commands; The real-time control command is output to the adjustment unit so that the adjustment unit adjusts the current parameters of the infrared heating element of the filament laying machine according to the real-time control command.

5. The infrared heating control method according to claim 4, characterized in that, Obtaining the current temperature data and current operating data of the fiber placement machine includes: Determine whether the fiber placement speed of the fiber placement machine is zero; If the determination result is negative, the current operating data and the current temperature data are obtained; wherein, the current operating data includes the placement speed of the filament placer, and the current temperature data includes the heating temperature, ambient temperature, and actual layup temperature; If the judgment result is yes, stop the operation of the infrared heating element of the filament laying machine.

6. The infrared heating control method according to claim 4, characterized in that, The set temperature data includes the set power. Obtaining the set temperature data for infrared heating based on the current temperature data and the current operating data includes: The set power of the infrared heating element of the filament laying machine is obtained according to the following relationship; ， in, This indicates the set power of the infrared heating element of the fiber placement machine. Represents the proportionality coefficient. Indicates the laying speed. This indicates the set temperature for the layup. This indicates the actual temperature of the ply.

7. The infrared heating control method according to claim 4, characterized in that, Based on the output temperature data and the set temperature data, the real-time control command for infrared heating is obtained, including: Calculate the deviation between the output temperature data and the set temperature data; The deviation is used as the input to the PID control algorithm, and the control quantity corresponding to the deviation is obtained according to the following relationship: ， in, To control the quantity, For deviation, For the proportional gain of the control law, Let be the integral time constant of the control law. Let be the differential time constant of the control law; The real-time control command is generated based on the control quantity corresponding to the deviation.

8. The infrared heating control method according to claim 4, characterized in that, After outputting the real-time control command to the adjustment unit so that the adjustment unit adjusts the current parameters of the infrared heating element of the filament laying machine according to the real-time control command, the method further includes: Return to the step of obtaining the current temperature data and the current operating data.

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