Automobile interior pad forming control method and system

Abstract

The invention provides an automotive trim pad forming control method and system, and relates to the technical field of automobile part manufacturing. The method comprises the following steps: determining an optimal temperature control curve in the hot press molding process according to the model of the interior mat; in the temperature rising sub-stage, the mold cavity is heated through the main heating module, and the current temperature maximum value is obtained according to the actual temperatures corresponding to the multiple monitoring points in the mold cavity; if the current temperature maximum value reaches the target constant temperature of the current temperature control stage, the main heating module is set to be in a constant temperature mode, and working parameters of the auxiliary heating module are configured according to the temperature maximum value and the actual temperature corresponding to each monitoring point; and after the continuous time of the main heating module in the constant-temperature mode reaches the target constant-temperature time, entering the next temperature control stage. Through cooperative control of the main heating module and the auxiliary heating module, it is ensured that the overall temperature of the die cavity rapidly reaches a target value and keeps stable, meanwhile, the local temperature difference is eliminated, and rapid response and steady-state precision of the temperature in the hot press forming process are both considered.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile parts manufacturing, and in particular to a method and system for controlling the molding of an automobile interior trim pad. Background Art

[0002] With the rapid development of the automotive industry, consumers are increasingly demanding higher quality for automotive interior components, especially for interior cushions, whose dimensional accuracy, surface finish, and molding stability directly impact the comfort and aesthetics of the vehicle. Hot press molding is a critical step in ensuring the dimensional accuracy and surface quality of automotive interior cushions. Traditional hot press molding processes rely heavily on manual temperature control, resulting in low temperature control accuracy and poor molding consistency. This can easily lead to incomplete material melting or localized overheating, impacting product yield.

[0003] In recent years, to improve the quality of hot-press molding, the industry has gradually introduced automated temperature control technologies, such as using PID algorithms to adjust heating power or setting temperature curves in stages to enhance the stability of the molding process. However, these methods still struggle to effectively eliminate local temperature differences within the mold cavity and lack dynamic adjustment capabilities, making it difficult to achieve both rapid temperature response and steady-state accuracy. Summary of the Invention

[0004] The purpose of the present invention is to provide a method and system for controlling the molding of automotive interior trim pads. By coordinating the control of the main heating module and the auxiliary heating module, it is ensured that the overall temperature of the mold cavity quickly reaches the target value and remains stable, while eliminating local temperature differences, so as to take into account both the rapid temperature response and steady-state accuracy during the hot pressing molding process.

[0005] In a first aspect, the present invention provides a method for controlling the molding of an automobile interior trim pad, comprising the steps of: Determining an optimal temperature control curve for the hot pressing process according to the interior trim pad model; the optimal temperature control curve includes several temperature control stages; the temperature control stages include a heating sub-stage and a constant temperature sub-stage; each constant temperature sub-stage has a corresponding target constant temperature temperature and target constant temperature time; In the heating sub-stage, the mold cavity is heated by the main heating module, and the current maximum temperature is obtained based on the actual temperatures corresponding to several monitoring points in the mold cavity; If the current maximum temperature reaches the target constant temperature of the current temperature control stage, the main heating module is set to the constant temperature mode, and the working parameters of the auxiliary heating module are configured according to the maximum temperature and the actual temperature corresponding to each monitoring point; After the duration of the main heating module in the constant temperature mode reaches the target constant temperature time, it enters the next temperature control stage.

[0006] As a preferred embodiment of the present invention, the method of determining the optimal temperature control curve for the hot pressing process according to the model of the interior trim pad specifically includes the following steps: S101. Determine the thermal parameters of each layer of material corresponding to the interior trim pad model through experiments; S102, constructing a test temperature control curve based on the material thermal parameters of each layer of material; the test temperature control curve includes several temperature control stages and corresponding target constant temperatures; S103, constructing a three-dimensional model of the interior cushion, and setting simulation parameters of the three-dimensional model according to the thermal parameters of the material; S104, simulating the three-dimensional model according to the test temperature control curve to obtain temperature simulation data corresponding to several time points; S105, obtaining the temperature standard deviation corresponding to each time point according to the temperature simulation data; S106. If the temperature standard deviation is greater than the first uniformity threshold, adjust the corresponding temperature control stage in the test temperature control curve according to the difference between the temperature standard deviation and the first uniformity threshold, and return to step S104; otherwise, use the test temperature control curve as the optimal temperature control curve.

[0007] As a preferred embodiment of the present invention, the corresponding temperature control stage in the adjustment test temperature control curve is specifically as follows: if the temperature standard deviation exceeds the standard in the heating sub-stage, the target heating rate is reduced and the target heating time is extended; if the temperature standard deviation exceeds the standard in the constant temperature sub-stage, the target constant temperature is increased and / or the target constant temperature time is extended.

[0008] As a preferred embodiment of the present invention, the method of heating the mold cavity by the main heating module comprises the following steps: Set fuzzy control rules; Calculate a first temperature error and a first error change rate according to the target constant temperature and the current maximum temperature; The first temperature error and the first error change rate are mapped into a fuzzy set, and the output power of the main heating module is determined according to the fuzzy set and the fuzzy control rule.

[0009] As a preferred embodiment of the present invention, heating the mold cavity by the main heating module comprises the following steps: Setting the fuzzy control rules of the first temperature rise control mode and the optimization objective function of the second temperature rise control mode; Calculate a first temperature error and a first error change rate according to the target constant temperature and the current maximum temperature; Determining a temperature rise control strategy according to the first temperature error and the first error change rate; the temperature rise control strategy includes a first temperature rise control mode and a second temperature rise control mode; The first temperature rise control mode is: mapping the first temperature error and the first error change rate into a fuzzy set, and determining the output power of the main heating module according to the fuzzy set and the fuzzy control rule; The second temperature rise control mode is: substituting the current maximum temperature into the optimization objective function to solve and obtain the output power of the main heating module.

[0010] As a preferred embodiment of the present invention, the temperature rise control strategy is determined based on the first temperature error and the first error change rate, specifically: when the first temperature error is greater than the first temperature error threshold or the first error change rate is greater than the first error change rate threshold, the first temperature rise control mode is selected as the temperature rise control strategy; when the first temperature error is less than or equal to the first temperature error threshold and the first error change rate is less than or equal to the first error change rate threshold, the second temperature rise control mode is selected as the temperature rise control strategy.

[0011] As a preferred solution of the present invention, the optimization objective function is expressed as: ; in, Indicates the target constant temperature, represents the prediction time domain, represents the control time domain, represents the input weight coefficient, Indicates the power change; Indicates the current maximum temperature.

[0012] As a preferred solution of the present invention, configuring the working parameters of the auxiliary heating module according to the maximum temperature and the actual temperature corresponding to each monitoring point includes the following steps: Calculate the second temperature error between each monitoring point and the maximum temperature in real time; If the second temperature error is greater than the auxiliary heating requirement threshold, calculating the second error change rate according to the difference between the second temperature errors in two adjacent time steps; The output power of the auxiliary heating module is configured according to the second temperature error.

[0013] As a preferred embodiment of the present invention, the output power of the auxiliary heating module is expressed as: ; in, represents the output power of the i-th electric heating element of the auxiliary heating module; represents the second temperature error of the i-th monitoring point; is the error gain coefficient; is the differential gain; i is the number of the monitoring point and the electric heating element.

[0014] In a second aspect, the present invention further provides an automobile interior cushion molding control system for implementing the above-mentioned automobile interior cushion molding control method, comprising a main heating module, an auxiliary heating module, a temperature monitoring module, a main heating control module, and an auxiliary heating control module; The main heating module includes a hot oil device, a circulation pump and an oil tank; The auxiliary heating module includes several electric heating elements; The temperature monitoring module is used to obtain the actual temperatures corresponding to several monitoring points in the mold cavity; The main heating control module is configured to determine an optimal temperature control curve for the hot pressing process according to the model of the interior trim pad; control the main heating module to heat the mold cavity during the temperature rise sub-stage, and obtain a current maximum temperature based on the actual temperatures corresponding to the plurality of monitoring points; and set the main heating module to a constant temperature mode when the current maximum temperature reaches a target constant temperature for the current temperature control stage; The auxiliary heating control module is used to configure the working parameters of the auxiliary heating module according to the maximum temperature and the actual temperature corresponding to each monitoring point.

[0015] The beneficial effects of the present invention are: The present invention ensures sufficient melting and shaping of the material through time-driven automatic stage switching based on the optimal temperature control curve, thereby improving product dimensional accuracy and surface quality; through the coordinated control of the main heating module and the auxiliary heating module, it ensures that the overall temperature of the mold cavity quickly reaches the target value and remains stable, while eliminating local temperature differences, so as to take into account both the rapid response of temperature and steady-state accuracy during the hot pressing process.

[0016] The present invention quickly approaches the target temperature through the fuzzy logic of the first temperature rise control mode, and then accurately suppresses overshoot through model prediction of the second temperature rise control mode. The dynamic switching strategy based on the first temperature error and the first error change rate takes into account both real-time performance and control accuracy to adapt to the application scenario of high-precision molding.

[0017] The present invention establishes independent closed-loop control for each auxiliary heating element, calculates the optimal power sequence in the predicted time domain, reduces ineffective energy consumption, accurately compensates for temperature lag at the mold edge or in complex contour areas, and improves overall temperature uniformity. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0020] Figure 1 1 is a flow chart of a method for controlling the molding of an automobile interior trim pad according to an embodiment of the present invention; Figure 2 A schematic diagram of a process for determining an optimal temperature control curve for a hot pressing process according to an interior trim pad model according to an embodiment of the present invention; Figure 3 Schematic diagram of the process of heating the mold cavity by the main heating module according to one embodiment of the present invention; Figure 4 Schematic diagram of the process of heating the mold cavity by the main heating module according to another embodiment of the present invention. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0022] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0023] In addition, the descriptions of "first", "second", etc. in the present invention are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0024] Example 1 Please refer to Figure 1 The present invention provides a method for controlling the molding of an automobile interior trim pad, comprising the steps of: Determining an optimal temperature control curve for a hot pressing process according to the interior trim pad model; the optimal temperature control curve includes several temperature control stages; the temperature control stages include a heating sub-stage and a constant temperature sub-stage; In the heating sub-stage, the mold cavity is heated by the main heating module, and the current maximum temperature is obtained based on the actual temperatures corresponding to several monitoring points in the mold cavity; If the current maximum temperature reaches the target constant temperature of the current temperature control stage, the main heating module is set to the constant temperature mode, and the working parameters of the auxiliary heating module are configured according to the maximum temperature and the actual temperature corresponding to each monitoring point.

[0025] After the duration of the main heating module in the constant temperature mode reaches the target constant temperature time, it enters the next temperature control stage.

[0026] In the present invention, the optimal temperature control curve is divided into multiple temperature control stages, each of which includes a temperature rise sub-stage and a constant temperature sub-stage. The main heating module performs the following operations according to the preset temperature control curve: In the heating sub-stage, the mold cavity is quickly heated to the target temperature. The heating rate and time need to be controlled to avoid uneven temperature gradients.

[0027] In the constant temperature sub-stage, the target temperature is maintained stable to ensure that the material is fully melted or shaped until the preset target constant temperature time is reached. The specific implementation method is that the main heating module maintains the temperature stable through PID control or fuzzy logic, while the auxiliary heating module compensates for local temperature differences (such as the low temperature area at the junction of thick and thin layers). In a temperature control stage, the trigger condition for switching from the heating sub-stage to the constant temperature sub-stage is: when the maximum temperature of the mold cavity surface reaches the target constant temperature of the current temperature control stage, the main heating module switches to the constant temperature mode.

[0028] When entering the constant temperature sub-stage, the system's built-in timer records the duration of the constant temperature mode. When the constant temperature mode duration equals or exceeds the preset target constant temperature time, the current temperature control stage is considered complete. Before the current temperature control stage is completed, the parameters for the next temperature control stage are loaded according to the optimal temperature control curve. When the current temperature control stage is determined to be complete, the system switches from the constant temperature sub-stage of the current temperature control stage to the next temperature control stage or enters the cooling stage.

[0029] The present invention ensures sufficient melting and shaping of the material through time-driven automated stage switching based on the optimal temperature control curve, thereby improving product dimensional accuracy and surface quality; through the coordinated control of the main heating module and the auxiliary heating module, it ensures that the overall temperature of the mold cavity quickly reaches the target value and remains stable, while eliminating local temperature differences.

[0030] Specifically, the steps of a method for controlling the molding of an automobile interior trim pad according to an embodiment of the present invention are described in detail through the following content: A method for controlling the molding of an automobile interior trim pad comprises the following steps: S1. Determine an optimal temperature control curve for a hot press molding process based on the interior trim pad model; the optimal temperature control curve includes several temperature control stages; the temperature control stages include a heating sub-stage and a constant temperature sub-stage; Different interior cushion models correspond to different material combinations, thicknesses, and contour complexities. Based on the interior cushion model, the optimal temperature control curve is matched and divided into several temperature control stages. Each temperature control stage includes several groups of heating sub-stages and constant temperature sub-stages. The heating sub-stage has corresponding target heating rates and target heating times: for example, extending from 30 seconds to 35 seconds to achieve a more uniform temperature distribution. The constant temperature sub-stage has corresponding target constant temperature temperatures and target constant temperature times. For example, for PU foam materials, the temperature can be quickly raised to a certain temperature, then maintained constant for a certain target constant temperature time, and then raised to the final molding temperature.

[0031] In one embodiment, please refer to Figure 2 , determine the optimal temperature control curve for the hot pressing process according to the interior trim pad model, specifically including the following steps: S101. Determine the thermal parameters of each layer of material corresponding to the interior trim pad model through experiments; The material thermal data includes thermal conductivity, specific heat capacity, glass transition temperature and melting temperature. In this step, each layer of the interior cushion material is tested separately, and the material thermal parameters of each layer of material are recorded. Specifically, the glass transition temperature and melting temperature of the material can be determined by a differential scanning calorimeter, and the thermal conductivity and specific heat of the material can be measured by a thermal conductivity tester to extend the target constant temperature time: for example, from 30 seconds to 35 seconds to make the temperature distribution more uniform. The glass transition temperature and melting temperature serve as the core basis for subsequent temperature control curve design and temperature simulation. In one embodiment, the interior cushion is hot-pressed from a composite material consisting of a fabric layer (PET / PA), an intermediate skeleton layer (PE / PP / EVA) and a base material layer (non-woven fabric).

[0032] S102, constructing a test temperature control curve based on the material thermal parameters of each layer of material; the test temperature control curve includes several temperature control stages and corresponding target constant temperatures; Based on prior knowledge, the target heating rate and target heating time of the heating sub-stage are set according to the glass transition temperature of the material thermal parameters, and the target constant temperature and target constant temperature time of the constant temperature sub-stage are set according to the melting temperature.

[0033] S103, constructing a three-dimensional model of the interior cushion, and setting simulation parameters of the three-dimensional model according to the thermal parameters of the material; Specifically, this step uses simulation software (such as COMSOL) to establish a three-dimensional model of the interior cushion mold and divides the laminated structure of the three-dimensional model according to the actual size and structural characteristics of the interior cushion. Then, the material thermal conductivity and specific heat capacity measured in S101 are input into the three-dimensional model to define the thermal properties of the laminated structure in the simulation software.

[0034] S104, simulating the three-dimensional model according to the test temperature control curve to obtain temperature simulation data corresponding to several time points; Based on the above process, the simulation model file containing material properties and mold structure is obtained. Load the test temperature control curve and perform transient heat conduction simulation at the set first time step (e.g., every 5 seconds). Then, use the first time step as the data collection interval to extract temperature simulation data from several sampling locations on the mold surface. Sampling locations include uniformly sampled grid points, as well as the center, edges, and thick-thin interface.

[0035] S105, obtaining the temperature standard deviation corresponding to each time point according to the temperature simulation data; For each sampling time point, the temperature standard deviation of the sampling time point is automatically calculated based on the temperature simulation data of several sampling positions on the mold surface.

[0036] S106. If the temperature standard deviation is greater than the first uniformity threshold, adjust the corresponding temperature control stage in the test temperature control curve according to the difference between the temperature standard deviation and the first uniformity threshold, and return to step S104; otherwise, use the test temperature control curve as the optimal temperature control curve.

[0037] This embodiment experimentally measures the thermal parameters of the material and constructs a three-dimensional simulation model to optimize the temperature control curve to guide the setting of process parameters, reduce trial and error costs, and ensure the temperature control adaptability and process stability of different interior trim pad models.

[0038] Based on a set first uniformity threshold (e.g., 3°C), mark the time points and corresponding temperature control stages where the temperature standard deviation exceeds the first uniformity threshold. If the temperature standard deviation of a temperature control stage exceeds the first uniformity threshold, adjust the corresponding temperature control stage in the test temperature control curve.

[0039] In one embodiment, the corresponding temperature control stage in the adjustment test temperature control curve is specifically as follows: if the temperature standard deviation exceeds the standard in the heating sub-stage, the target heating rate is reduced and the target heating time is extended; if the temperature standard deviation exceeds the standard in the constant temperature sub-stage, the target constant temperature temperature is increased and / or the target constant temperature time is extended.

[0040] In the present invention, the main reason for the temperature standard deviation exceeding the standard in the heating sub-stage is that the target heating rate is too fast or the target heating time is insufficient, resulting in excessive temperature gradients in different areas of the mold. Specifically, this may be because the thick-walled area has a large heat capacity and the heating lags behind the thin-walled area. Therefore, it is necessary to reduce the temperature gradient, for example, from 5°C / s to 3°C / s to ensure more uniform heat transfer; or because the heat absorption efficiency of the complex contour area is uneven, the local temperature deviates from the expected value. Therefore, it is necessary to provide more time for the thick-walled or complex area to absorb heat. The main reason for the temperature standard deviation exceeding the standard in the constant temperature sub-stage is that the target constant temperature or time is insufficient, resulting in insufficient material melting or unstable temperature distribution. Specifically, this may be because the target constant temperature at the sampling point is lower than the material melting temperature, resulting in incomplete melting in some areas. Therefore, it is necessary to increase the target constant temperature to ensure that the material melting requirements are met; or the target constant temperature time is too short, and the heat is not fully transferred to the deep area of ​​the mold. Therefore, it is necessary to extend the target constant temperature time to achieve a more uniform temperature distribution.

[0041] This embodiment dynamically adjusts the temperature control parameters in the exceeding-standard stage to set the target heating rate, target heating time, target constant temperature and extend the target constant temperature time, so as to specifically eliminate the problem of uneven temperature distribution, for example, to alleviate the temperature lag caused by the difference in heat capacity between thick and thin areas.

[0042] S2. In the heating sub-stage, the mold cavity is heated by the main heating module, and the current maximum temperature is obtained based on the actual temperatures corresponding to several monitoring points in the mold cavity; At the start of the heating sub-phase, the main heating module is activated to heat the entire mold cavity. During the heating process, the temperature data of each monitoring point in the mold cavity is monitored in real time and recorded as the temperature data corresponding to the monitoring point. Furthermore, the maximum temperature among the temperature data of the monitoring points is calculated in real time. In the present invention, the monitoring points are typically distributed at key locations in the mold cavity, typically uniformly sampled grid points, areas with uneven material thickness, or areas with complex contours.

[0043] In one embodiment, the main heating module is an oil heating circulation device, which includes a hot oil unit, a circulation pump, and an oil tank. The hot oil unit heats the thermal oil; the circulation pump transports the thermal oil from the hot oil unit to the mold cavity and returns the return oil to the hot oil unit for reheating; and the oil tank stores the thermal oil to ensure smooth circulation.

[0044] During the process, the thermal oil in the hot oil furnace is heated electrically or by steam to a target constant temperature, typically between 100°C and 300°C, depending on the requirements of the interior cushion material. A circulating pump delivers the hot oil to heating pipes or coils within the mold cavity. Heat is then transferred to the interior cushion material through heat conduction, ensuring a uniform temperature increase throughout the cavity.

[0045] In one embodiment, please refer to Figure 3 The heating of the mold cavity by the main heating module comprises the following steps: S211, setting fuzzy control rules; The fuzzy control rule defines the input variables as the first temperature error and the first error change rate, and uses a triangular membership function to process the first temperature error and the first error change rate, dividing them into five fuzzy levels, including negative large (NB), negative small (NS), zero (ZE), positive small (PS), and positive large (PB); and sets the fuzzy output corresponding to the fuzzy level of the first temperature error and the first error change rate (for example: "If the error is positive and the first error change rate is positive, then increase the power significantly").

[0046] S212, calculating a first temperature error and a first error change rate according to the target constant temperature and the current maximum temperature; The temperatures of all monitoring points on the mold cavity surface are read in real time, and the maximum value is taken as the current maximum temperature. The first temperature error is then obtained by subtracting the current maximum temperature from the target constant temperature. The first error change rate is obtained by dividing the difference between the first temperature errors of two adjacent time steps by the first time step.

[0047] S213 , mapping the first temperature error and the first error change rate into a fuzzy set, and determining the output power of the main heating module according to the fuzzy set and the fuzzy control rule.

[0048] Based on the aforementioned fuzzy level, this step maps the first temperature error and the first error change rate into a fuzzy set (including "negative large", "negative small", "zero", "positive small", and "positive large"), and then obtains the fuzzy output according to the fuzzy control rules and converts it into a specific power adjustment value.

[0049] This embodiment achieves rapid response through fuzzy control. Since the first temperature error and the first error change rate are mapped into fuzzy sets and the output power of the main heating module is determined according to the fuzzy control rules, no precise mathematical model is required to adapt to the nonlinearity of the system.

[0050] In another embodiment, see Figure 4 The heating of the mold cavity by the main heating module comprises the following steps: S221, setting the fuzzy control rules of the first temperature rise control mode and the optimization objective function of the second temperature rise control mode; The fuzzy control rules of the first temperature rise control mode are the same as S211 of the aforementioned embodiment. The fuzzy control rules define the input variables as the first temperature error and the first error change rate, and use a triangular membership function to process the first temperature error and the first error change rate, dividing them into five fuzzy levels, including negative large (NB), negative small (NS), zero (ZE), positive small (PS), and positive large (PB); and set the fuzzy outputs corresponding to the fuzzy levels of the first temperature error and the first error change rate.

[0051] The optimization objective function of the second temperature rise control mode is constructed by a first-order heat conduction model. The first-order heat conduction model is expressed as: ; in, Indicates the current maximum temperature. It indicates the maximum temperature of the next time step. represents the first time step, represents the output power at the current time step, represents the ambient temperature, R represents the thermal resistance, and C represents the heat capacity. The values ​​of thermal resistance R and heat capacity C are fitted through experiments.

[0052] The optimization objective function is expressed as: ; in, Indicates the target constant temperature, represents the prediction time domain, represents the control time domain, represents the input weight coefficient, Indicates the power change, . And, the optimization objective function satisfies the constraints: , in, The maximum output power of the main heating module.

[0053] S222, calculating a first temperature error and a first error change rate according to the target constant temperature and the current maximum temperature; Step S222 is the same as S212 in the aforementioned embodiment, and the temperatures of all monitoring points on the mold cavity surface are read in real time, and the maximum value is taken as the current temperature maximum value. Then, the first temperature error is obtained by subtracting the current temperature maximum value from the target constant temperature, and the first error change rate is obtained by dividing the difference between the first temperature errors of two adjacent time steps by the first time step.

[0054] S223, determining a temperature rise control strategy according to the first temperature error and the first error change rate; the temperature rise control strategy includes a first temperature rise control mode and a second temperature rise control mode; The first temperature rise control mode is: mapping the first temperature error and the first error change rate into a fuzzy set, and determining the output power of the main heating module according to the fuzzy set and the fuzzy control rule; The second temperature rise control mode is: substituting the current maximum temperature into the optimization objective function to solve and obtain the output power of the main heating module.

[0055] Furthermore, the temperature rise control strategy is determined based on the first temperature error and the first error change rate, specifically: when the first temperature error is greater than the first temperature error threshold or the first error change rate is greater than the first error change rate threshold, the first temperature rise control mode is selected as the temperature rise control strategy; when the first temperature error is less than or equal to the first temperature error threshold and the first error change rate is less than or equal to the first error change rate threshold, the second temperature rise control mode is selected as the temperature rise control strategy.

[0056] For example, when the first temperature error is greater than 5°C or the first error change rate is greater than 2°C / s, the first heating mode is used to quickly eliminate large deviations; when the first temperature error is ≤5°C and the first error change rate is ≤2°C / s, the second heating mode is used for fine-tuning.

[0057] This embodiment uses the fuzzy logic of the first temperature rise control mode to quickly approach the target temperature, and then accurately suppresses overshoot through model prediction of the second temperature rise control mode. The dynamic switching strategy based on the first temperature error and the first error change rate takes into account both real-time performance and control accuracy to adapt to the application scenario of high-precision molding.

[0058] S3. If the current maximum temperature reaches the target constant temperature of the current temperature control stage, the main heating module is set to the constant temperature mode, and the working parameters of the auxiliary heating module are configured according to the maximum temperature and the actual temperature corresponding to each monitoring point.

[0059] Once the maximum temperature reaches the target constant temperature, the main heating module switches to constant temperature mode to maintain the current temperature. Specifically, after switching to constant temperature mode, the main heating module controls the current maximum temperature within an allowable deviation from the target constant temperature, such as ±0.5°C. The difference between the maximum temperature and the actual temperature at each monitoring point is then calculated to determine the temperature deviation at each point. Based on these deviations, the operating parameters of the auxiliary heating module are configured to locally compensate for the temperature differences.

[0060] It should be noted that the optimal temperature control curve is generated based on the thermal parameters of the material and the three-dimensional simulation model. Its essence is a solution that satisfies the temperature standard deviation less than or equal to the first uniformity threshold, which is used to provide a theoretical basis for the control of the main heating module. However, the thermal conductivity characteristics of the multi-layer materials of the interior cushion (such as the substrate and the foam layer) may vary from batch to batch, and the heat absorption rate of complex geometric contours or thick-thin junction areas is different. It is difficult for the simulation to fully cover all local dynamic characteristics. This embodiment collects temperature data in real time through monitoring points to identify local low-temperature areas (such as edges or thick-thin junctions), and then uses the auxiliary heating module to independently adjust the power according to the second temperature error and change rate to compensate for the insufficient heat area in a targeted manner.

[0061] In one embodiment, the auxiliary heating module includes several electric heating elements. During implementation, the electric heating elements are installed near the monitoring points, which can quickly respond and adjust the local temperature to ensure that the temperature in the entire mold cavity is uniform and avoid local overheating or overcooling.

[0062] Furthermore, configuring the working parameters of the auxiliary heating module according to the maximum temperature and the actual temperature corresponding to each monitoring point includes the steps of: S31, calculating in real time the second temperature error between each monitoring point and the maximum temperature; S32: If the second temperature error is greater than the auxiliary heating requirement threshold, calculating a second error change rate according to a difference in the second temperature errors between two adjacent time steps; The second error change rate is expressed as: ; in, represents the second error change rate of the i-th monitoring point, represents the second temperature error of the kth time step at the i-th monitoring point, represents the second time step.

[0063] S33. Configure the output power of the auxiliary heating module according to the second temperature error.

[0064] The output power of the auxiliary heating module is expressed as: ; in, represents the output power of the i-th electric heating element of the auxiliary heating module; represents the second temperature error of the i-th monitoring point; is the error gain coefficient, which is set according to the material heat capacity and heating efficiency; is the differential gain; i is the number of the monitoring point and the electric heating element.

[0065] In the formula, the first term The difference between the current monitoring point and the maximum temperature directly reflects the intensity of heating demand. The second item The heating demand intensity is further optimized according to the second error change rate to suppress temperature fluctuations in advance.

[0066] This embodiment establishes independent closed-loop control for each auxiliary heating element, calculates the optimal power sequence in the prediction time domain, reduces ineffective energy consumption, accurately compensates for temperature lag at the mold edge or in areas with complex contours, and improves overall temperature uniformity.

[0067] S4, monitoring the main heating module, and after the constant temperature mode duration reaches the target constant temperature time, entering the next temperature control stage.

[0068] In the present invention, the temperature control curve is divided into multiple temperature control stages, each stage including a temperature rise sub-stage and a constant temperature sub-stage. The main heating module performs the following operations according to the preset temperature control curve: In the heating sub-stage, the mold cavity is quickly heated to the target temperature. The heating rate and time need to be controlled to avoid uneven temperature gradients.

[0069] In the constant temperature sub-stage, the target temperature is maintained stable to ensure that the material is fully melted or shaped until the preset target constant temperature time is reached. The specific implementation method is that the main heating module maintains the temperature stable through PID control or fuzzy logic, while the auxiliary heating module compensates for local temperature differences (such as the low temperature area at the junction of thick and thin layers). In a temperature control stage, the trigger condition for switching from the heating sub-stage to the constant temperature sub-stage is: when the maximum temperature of the mold cavity surface reaches the target constant temperature of the current temperature control stage, the main heating module switches to the constant temperature mode.

[0070] When entering the constant temperature sub-stage, the system's built-in timer records the duration of the constant temperature mode. When the duration of the constant temperature mode is equal to or exceeds the preset target constant temperature time, the current temperature control stage is determined to be completed. Before the current temperature control stage is completed, the parameters of the next temperature control stage are loaded according to the optimal temperature control curve, including the target heating rate, target heating time, target constant temperature and target constant temperature time of the next temperature control stage. When it is determined that the current temperature control stage is completed, the constant temperature sub-stage of the current temperature control stage is switched to the next temperature control stage or the cooling stage is entered. If the next temperature control stage is entered, the system returns to step S2. In one embodiment, the target processing temperature curve includes a first temperature control stage, a second temperature control stage, a third temperature control stage and a cooling stage. A method for controlling the molding of an automotive interior trim pad of the present invention implements the first temperature control stage, the second temperature control stage and the third temperature control stage respectively by cyclically executing steps S2-S4 three times, and then executes the cooling stage. Since the cooling stage can be implemented by existing methods, this solution will not be described in detail.

[0071] Example 2 The present invention also provides an automobile interior trim pad molding control system, comprising a main heating module, an auxiliary heating module, a temperature monitoring module, a main heating control module and an auxiliary heating control module; The main heating module includes a hot oil device, a circulation pump and an oil tank; The auxiliary heating module includes several electric heating elements; The temperature monitoring module is used to obtain the actual temperatures corresponding to several monitoring points in the mold cavity; The main heating control module is configured to determine an optimal temperature control curve for the hot pressing process according to the model of the interior trim pad; control the main heating module to heat the mold cavity during the temperature rise sub-stage, and obtain a current maximum temperature based on the actual temperatures corresponding to the plurality of monitoring points; and set the main heating module to a constant temperature mode when the current maximum temperature reaches a target constant temperature for the current temperature control stage; The auxiliary heating control module is used to configure the working parameters of the auxiliary heating module according to the maximum temperature and the actual temperature corresponding to each monitoring point.

[0072] In the embodiments provided in this application, it should be understood that the disclosed systems and methods can be implemented in other ways. For example, the system embodiments described above are merely illustrative. For example, the division of the modules is merely a logical function division. In actual implementation, there may be other division methods, such as multiple modules or component libraries can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of modules, which can be electrical, mechanical or other forms.

[0073] The modules described as separate components may or may not be physically separate, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed across multiple grid modules. Some or all of the modules may be selected to achieve the purpose of this embodiment according to actual needs.

[0074] In addition, the functional modules in the various embodiments of the present application may be integrated into a processing module, or each module may exist physically separately, or two or more modules may be integrated into a single module. The above-mentioned integrated modules may be implemented in the form of hardware or software functional modules.

[0075] If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, or the part that contributes to the existing technology, or all or part of the technical solution can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or grid device, etc.) to execute all or part of the steps of the method described in each embodiment of this application. The aforementioned storage medium includes: USB flash drives, dynamic hard drives, read-only memories (ROM), random access memories (RAM), magnetic disks, optical disks, and other media that can store program code.

[0076] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is intended to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for controlling the molding of an automobile interior trim pad, characterized in that: Including steps: Determining an optimal temperature control curve for the hot pressing process according to the interior trim pad model; the optimal temperature control curve includes several temperature control stages; the temperature control stages include a heating sub-stage and a constant temperature sub-stage; each constant temperature sub-stage has a corresponding target constant temperature temperature and target constant temperature time; In the heating sub-stage, the mold cavity is heated by the main heating module, and the current maximum temperature is obtained based on the actual temperatures corresponding to several monitoring points in the mold cavity; If the current maximum temperature reaches the target constant temperature of the current temperature control stage, the main heating module is set to the constant temperature mode, and the working parameters of the auxiliary heating module are configured according to the maximum temperature and the actual temperature corresponding to each monitoring point; After the duration of the constant temperature mode of the monitoring main heating module reaches the target constant temperature time, it enters the next temperature control stage.

2. The method for controlling the molding of an automobile interior trim pad according to claim 1, wherein: Determining the optimal temperature control curve for the hot pressing process according to the interior trim pad model specifically includes the following steps: S101. Determine the material thermal parameters of each layer of the interior trim pad corresponding to the model through experiments; S102, constructing a test temperature control curve based on the material thermal parameters of each layer of material; the test temperature control curve includes several temperature control stages and corresponding target constant temperatures; S103, constructing a three-dimensional model of the interior trim pad, and setting simulation parameters of the three-dimensional model according to the thermal parameters of the material; S104, simulating the three-dimensional model according to the test temperature control curve to obtain temperature simulation data corresponding to several time points; S105, obtaining the temperature standard deviation corresponding to each time point according to the temperature simulation data; S106. If the temperature standard deviation is greater than the first uniformity threshold, adjust the corresponding temperature control stage in the test temperature control curve according to the difference between the temperature standard deviation and the first uniformity threshold, and return to step S104; otherwise, use the test temperature control curve as the optimal temperature control curve.

3. The method for controlling the molding of an automobile interior trim pad according to claim 2, characterized in that: The corresponding temperature control stage in the adjustment test temperature control curve is specifically as follows: if the temperature standard deviation exceeds the standard in the heating sub-stage, the target heating rate is reduced and the target heating time is extended; if the temperature standard deviation exceeds the standard in the constant temperature sub-stage, the target constant temperature is increased and / or the target constant temperature time is extended.

4. The method for controlling the molding of an automobile interior trim pad according to claim 1, wherein: The method of heating the mold cavity by the main heating module comprises the following steps: Set fuzzy control rules; Calculate a first temperature error and a first error change rate according to the target constant temperature and the current maximum temperature; The first temperature error and the first error change rate are mapped into a fuzzy set, and the output power of the main heating module is determined according to the fuzzy set and the fuzzy control rule.

5. The method for controlling the molding of an automobile interior trim pad according to claim 1, characterized in that: The heating of the mold cavity by the main heating module comprises the following steps: Setting the fuzzy control rules of the first temperature rise control mode and the optimization objective function of the second temperature rise control mode; Calculate a first temperature error and a first error change rate according to the target constant temperature and the current maximum temperature; Determining a temperature rise control strategy according to the first temperature error and the first error change rate; the temperature rise control strategy includes a first temperature rise control mode and a second temperature rise control mode; The first temperature rise control mode is: mapping the first temperature error and the first error change rate into a fuzzy set, and determining the output power of the main heating module according to the fuzzy set and the fuzzy control rule; The second temperature rise control mode is: substituting the current maximum temperature into the optimization objective function to solve and obtain the output power of the main heating module.

6. The method for controlling the molding of an automobile interior trim pad according to claim 5, characterized in that: The temperature rise control strategy is determined based on the first temperature error and the first error change rate, specifically: when the first temperature error is greater than the first temperature error threshold or the first error change rate is greater than the first error change rate threshold, the first temperature rise control mode is selected as the temperature rise control strategy; when the first temperature error is less than or equal to the first temperature error threshold and the first error change rate is less than or equal to the first error change rate threshold, the second temperature rise control mode is selected as the temperature rise control strategy.

7. The method for controlling the molding of an automobile interior trim pad according to claim 6, characterized in that: The optimization objective function is expressed as: ； in, Indicates the target constant temperature, represents the prediction time domain, represents the control time domain, represents the input weight coefficient, Indicates the power change; Indicates the current maximum temperature.

8. The method for controlling the molding of an automobile interior trim pad according to claim 1, characterized in that: The method of configuring the operating parameters of the auxiliary heating module according to the maximum temperature and the actual temperature corresponding to each monitoring point includes the following steps: Calculate the second temperature error between each monitoring point and the maximum temperature in real time; If the second temperature error is greater than the auxiliary heating requirement threshold, calculating the second error change rate according to the difference between the second temperature errors in two adjacent time steps; The output power of the auxiliary heating module is configured according to the second temperature error.

9. The method for controlling the molding of an automobile interior trim pad according to claim 1, characterized in that: The output power of the auxiliary heating module is expressed as: ； in, represents the output power of the i-th electric heating element of the auxiliary heating module; represents the second temperature error of the i-th monitoring point; is the error gain coefficient; is the differential gain; i is the number of the monitoring point and the electric heating element.

10. An automobile interior trim pad molding control system, characterized by: Used to implement an automobile interior trim pad molding control method as described in any one of claims 1 to 9, comprising a main heating module, an auxiliary heating module, a temperature monitoring module, a main heating control module and an auxiliary heating control module; The main heating module includes a hot oil device, a circulation pump and an oil tank; The auxiliary heating module includes several electric heating elements; The temperature monitoring module is used to obtain the actual temperatures corresponding to several monitoring points in the mold cavity; The main heating control module is configured to determine an optimal temperature control curve for the hot pressing process according to the model of the interior trim pad; control the main heating module to heat the mold cavity during the temperature rise sub-stage, and obtain a current maximum temperature based on the actual temperatures corresponding to the plurality of monitoring points; and set the main heating module to a constant temperature mode when the current maximum temperature reaches a target constant temperature for the current temperature control stage; The auxiliary heating control module is used to configure the working parameters of the auxiliary heating module according to the maximum temperature and the actual temperature corresponding to each monitoring point.

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