A low-temperature powder spraying and curing device based on gas catalytic infrared

Abstract

The application discloses a low-temperature powder spraying curing equipment based on gas catalytic infrared, which comprises a curing cavity, a conveying device, a control module, a gas supply module, a partition adjusting module and a temperature sensing array; the control module drives the servo motor according to the calculated target inclination angle and target azimuth angle, adjusts each radiation plate to a target posture, and adjusts the gas supply amount of each radiation plate through the partition adjusting module according to the target output power. By discretizing the workpiece surface into micro surface elements and establishing an optimization objective function and constraint condition of radiation illumination distribution, the application adopts a high-dimensional nonlinear optimization method such as a genetic algorithm to solve the optimal inclination angle, azimuth angle and output power of each radiation plate, can quickly generate an optimal radiation configuration scheme for any complex geometric workpiece, breaks through the curing mode of traditional equipment, and greatly improves the self-adaptive ability of the equipment to different workpieces and the consistency of curing quality.

Description

Technical Field

[0001] This application belongs to the field of powder coating curing technology, specifically relating to a low-temperature powder coating curing device based on gas-fired catalytic infrared radiation. Background Technology

[0002] Powder coating is a surface treatment process that involves spraying powder coating onto the surface of a workpiece and then heating and curing it to form a dense coating. Due to its advantages such as no solvent emissions, high coating utilization, and excellent coating performance, it has been widely used in various metal structural components in the new energy field. In the new energy vehicle and energy storage industries, components such as battery liquid cooling plates, power battery casings, battery pack housings, and energy storage cabinets all require powder coating to form protective coatings with functions such as insulation, flame retardancy, and corrosion resistance. Among these, the liquid cooling plate, as a core component of the battery pack thermal management system, also needs a coating with good thermal conductivity and dielectric strength; large structural components such as energy storage cabinets require coatings with excellent weather resistance and corrosion resistance.

[0003] Currently, powder coatings are mainly cured using the following two methods: One method is hot air convection curing. This method uses hot air as the heat transfer medium, circulating hot air to convectively heat the workpiece. Its advantages include uniform heating, precise temperature control, and suitability for complex-shaped objects. However, hot air convection curing has significant drawbacks: slow heating rate, high power consumption, and low thermal efficiency (typically only 30%–40%); the curing process relies on hot air circulation, easily causing secondary dust pollution; and the equipment is bulky and requires a large floor space. For relatively heavy structural components such as liquid cooling plates, brackets, cabinets, and connecting strips in energy storage battery packs, the traditional powder coating curing process results in slow heating and long baking times, leading to high energy consumption and low coating efficiency.

[0004] Second is electro-infrared radiation curing. This method utilizes the direct absorption of infrared radiation by the object, converting it into heat energy. It has the advantages of rapid heating and small equipment footprint. However, the temperature uniformity of electro-infrared heating is poor, and for workpieces with complex geometric features, there are radiation dead zones. Taking new energy battery shells and energy storage cabinets as examples, these workpieces often have complex structures such as recesses, internal corners, steps, and cavities, and usually require thick insulating coatings (a single spraying often cannot meet the thickness requirements, and the industry generally adopts a two-spray, two-bake process). In existing infrared curing equipment, the radiation plate is usually fixedly installed, and its irradiation angle and radiation power cannot be adaptively adjusted according to the actual geometry of the workpiece. This results in insufficient irradiance on the back side, shaded areas, and complex structural parts, leading to uneven coating curing and seriously affecting the insulation performance of the coating and the consistency of product quality.

[0005] In recent years, gas-fired catalytic infrared technology has attracted attention due to its advantages such as flameless combustion, high energy utilization, and good matching between infrared radiation wavelength and the absorption peak of powder coatings. Catalytic infrared radiation transfers heat via electromagnetic waves, requiring no intermediate medium; the heat acts directly on the coating, resulting in minimal heat loss during the energy supply process. Related research shows that catalytic infrared radiation plates mainly emit medium-to-long-wave infrared radiation in the 3–10 m range, which matches the absorption peak of powder coatings, leading to high curing efficiency. The time required for complete curing of coatings using catalytic infrared radiation is only half that of hot air curing. Catalytic combustion infrared radiation curing can save 760,000 yuan / year in natural gas costs and 63% of floor space.

[0006] However, existing gas-fired catalytic infrared curing equipment still has the following shortcomings: (1) Radiation plates are usually fixedly installed in the curing cavity. Their irradiation angle and radiation power cannot be adaptively adjusted according to the actual geometry of the workpiece. For workpieces with complex geometric features such as concave, inner corner, and step, the radiation energy is difficult to uniformly cover each surface area. The backlight and shadow areas are prone to incomplete curing due to insufficient radiation illuminance. (2) There is a lack of precise means to obtain the three-dimensional geometric information of the workpiece, and it is impossible to formulate differentiated radiation strategies according to the specific shape and size differences of the workpiece. The same set of curing parameters is difficult to adapt to the diverse workpieces of different batches. (3) The lack of real-time temperature distribution monitoring and feedback adjustment mechanism during the curing process makes it difficult to ensure the uniformity and stability of temperature in each area, which affects the consistency of coating quality. (4) The heating mode of each temperature zone in the curing chamber is singular, and it is impossible to intelligently switch and optimize the power allocation according to the needs of different process stages such as melting and leveling, cross-linking and curing of powder coating. Summary of the Invention

[0007] This application provides a low-temperature powder coating and curing device based on gas-catalyzed infrared curing, which aims to solve the problems of existing gas-catalyzed infrared curing devices being unable to adaptively adjust radiation parameters according to the workpiece geometry, having poor curing temperature uniformity, and insufficient adaptability to complex workpieces.

[0008] In the first aspect, a low-temperature powder coating curing device based on gas-catalyzed infrared radiation includes: a curing chamber, a conveying device, a control module, a gas supply module, a zone adjustment module, and a temperature sensing array. The curing chamber is divided into a preheating zone, a main curing zone and a constant temperature post-curing zone along the conveying direction, and each zone is independently equipped with a catalytic infrared radiation plate. The main curing zone is equipped with a multi-degree-of-freedom adjustable infrared radiation plate array, which consists of multiple catalytic infrared radiation plates. Each radiation plate is connected to the mounting bracket of the curing cavity through an independent universal adjustment mechanism. The universal adjustment mechanism is driven by a servo motor and can adjust the tilt angle and azimuth angle of each radiation plate. A vision scanning module is fixedly installed on the outside of the inlet end of the curing cavity. The vision scanning module is used to perform three-dimensional scanning of the workpiece and generate three-dimensional point cloud data of the workpiece. The control module receives the three-dimensional point cloud data generated by the visual scanning module, and generates a three-dimensional geometric model of the workpiece through point cloud processing and surface reconstruction. Based on the three-dimensional geometric model, the control module calculates the target tilt angle, target azimuth angle and target output power of each radiating plate in the multi-degree-of-freedom adjustable infrared radiating plate array with the optimization objective of maximizing the infrared irradiance received by each region of the workpiece surface and uniformizing the irradiance distribution. The control module drives the servo motor according to the calculated target tilt angle and target azimuth angle to adjust each radiating plate to the target attitude, and adjusts the gas supply of each radiating plate through the partition adjustment module according to the target output power.

[0009] Optionally, the control module establishes the following optimization objective function: The surface of the three-dimensional geometric model is discretized into several micro-surface elements. For the j-th micro-surface element, the total irradiance it receives is... It equals the sum of the irradiance contributed by each radiating plate to the micro-element: Where n is the total number of radiating plates, and the irradiance of a single radiating plate on a micro-element is... Determined by the following formula: In the formula, Let be the radiant power of the i-th radiating plate. and Let be the tilt angle and azimuth angle of the i-th radiating plate, respectively. The radiation directivity coefficient, The angle coefficient, For the incident angle of radiation, The spatial distance from the center of the radiating plate to the micro-facet element; The control module uses the average irradiance of all micro-facets. Maximize and standard deviation Minimize as the optimization objective, construct a comprehensive evaluation function: in, and These are weighting coefficients. , , where m is the total number of micro-surface elements.

[0010] Optionally, the control module uses the tilt angle of each radiating plate. Azimuth and output power To optimize the variables, solve the following constrained optimization problem: The constraints include: Tilt angle constraint: ; Azimuth constraint: ; Output power constraint: ,in For minimum stable operating power, Rated power; Minimum safe distance constraint between adjacent radiating panels: ,in and These are the spatial coordinates of the center points of two adjacent radiating plates. Minimum safe distance; Radiation irradiance upper limit constraint: ,in This represents the maximum permissible safe irradiance for powder coatings. And constraints on the combined working characteristics of the radiating plates: ,in Let be the joint operating characteristic constraint domain for the i-th radiating plate.

[0011] Optionally, when the workpiece geometry is complex or the number of radiating plates exceeds a preset threshold, the control module uses a genetic algorithm to solve the constraint optimization problem. (a) Chromosome encoding: The tilt angle of each radiating plate Azimuth and output power Encoded as binary chromosomes, each chromosome represents a pose and power configuration scheme for the radiating plate array; (ii) Initial population generation: N chromosomes are randomly generated as the initial population; (III) Fitness function design: Each chromosome is decoded into corresponding attitude parameters and power parameters. The irradiance distribution of each micro-element is calculated according to the irradiance calculation model. The monotonically increasing mapping of the comprehensive evaluation function F is used as the fitness function. (iv) Selection operation: Individuals are selected for the next generation of the population by combining roulette wheel selection with an elite retention strategy; (v) Crossover operation: based on crossover probability Crossover operations are performed on the selected parent individuals to generate offspring individuals; (vi) Mutation operation: based on mutation probability Perform mutation operations on gene loci in offspring individuals; (vii) Iteration termination judgment: Repeat steps (iv) to (vi) until the termination condition is met, and output the attitude parameters and power parameters corresponding to the individual with the highest fitness as the optimization result.

[0012] Optionally, the control module converts the target tilt angle and the target azimuth angle into the target rotation angle of each servo motor through inverse kinematics calculation, and then converts the target rotation angle into a pulse command according to the pulse equivalent of the servo motor and outputs it to each servo motor to drive the universal adjustment mechanism to adjust each radiating plate to the target attitude; The control module converts the target output power into a gas flow setpoint based on the power-gas flow characteristic curve of the catalytic infrared radiation plate, and then converts the gas flow setpoint into a valve opening control signal based on the flow-opening characteristic curve of the proportional regulating valve, which is then output to the zone regulating module.

[0013] Optionally, the visual scanning module includes at least one set of binocular structured light 3D cameras and a structured light projector. The binocular structured light 3D cameras consist of a left camera and a right camera, and the structured light projector is used to project coded structured light onto the surface of the workpiece. After binocular calibration, the visual scanning module synchronously acquires left and right image pairs carrying structured light patterns through the binocular structured light 3D camera. The disparity is calculated by the stereo matching algorithm, and the 3D point cloud of the workpiece surface is reconstructed by combining the camera calibration parameters. For workpieces larger than the preset size or with complex geometry, the vision scanning module performs segmented scanning or multi-angle scanning of the workpiece along the conveying direction, and the point cloud data obtained from multiple scans are spliced ​​and fused into a complete three-dimensional point cloud of the workpiece through coarse registration and fine registration. The control module sequentially performs filtering and noise reduction, downsampling compression, outlier removal, point cloud segmentation, and surface reconstruction on the three-dimensional point cloud to generate the three-dimensional geometric model, and identifies the geometric contour dimensions of the workpiece, the normal direction of each surface, the curvature distribution characteristics, and the location information of the shadow area.

[0014] Optionally, the temperature sensing array monitors the temperature distribution in various regions of the workpiece surface in real time and feeds back the measured temperature distribution to the control module; The control module compares the measured temperature distribution with the target temperature distribution. When the measured temperature of a certain area deviates from the target value, the control module dynamically fine-tunes the output power of the radiant panel corresponding to that area based on the temperature deviation signal. The fine-tuning amount is calculated using an incremental PID control algorithm. The control module records the attitude parameters, power parameters, and temperature distribution data for each curing process, and optimizes the weighting coefficients in the objective function using machine learning algorithms.

[0015] Optionally, the curing chamber is further equipped with a directional hot air circulation module, which includes a circulating fan and an air duct guide plate. The air inlet of the circulating fan is located at the top or upper side wall of the curing chamber, and the air outlet is connected to a plurality of air supply nozzles distributed on the inner wall of the curing chamber through an air duct. The air duct guide plate is located at the air supply nozzles and its angle is adjustable. The catalytic infrared radiation plate and the directional hot air circulation module share the same control module, and the two can operate independently or simultaneously. The control module switches the heating mode according to the curing process stage: During the melting and leveling stage, heating is mainly carried out by catalytic infrared radiation, which accounts for more than 80% of the total heating power. The directional hot air circulation module is turned off or operates at less than 10% of the rated air volume. During the cross-linking and curing stage, the system switches to a mixed heating mode of catalytic infrared radiation and micro-circulation hot air. The hot air temperature is set to a compensation temperature that is 3 to 5 degrees Celsius lower than the current curing temperature, and the air volume is set to 30% to 50% of the rated air volume.

[0016] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, performs the following steps: Acquire the 3D point cloud data generated by the vision scanning module after scanning the workpiece in 3D; The three-dimensional point cloud data is processed by point cloud processing and surface reconstruction to generate a three-dimensional geometric model of the workpiece. Based on the three-dimensional geometric model, with the optimization objective of maximizing the infrared radiation irradiance received by each region of the workpiece surface and uniformizing the radiation irradiance distribution, the target tilt angle, target azimuth angle and target output power of each radiation plate in the multi-degree-of-freedom adjustable infrared radiation plate array are calculated. The servo motor is driven according to the target tilt angle and the target azimuth angle to adjust each radiating plate to the target attitude, and the gas supply of each radiating plate is adjusted by the partition adjustment module according to the target output power.

[0017] Compared with the prior art, this application has at least the following beneficial effects: Based on further analysis and research of existing technical problems, this application recognizes the shortcomings of existing gas-fired catalytic infrared curing equipment, such as the fixed posture of the radiating plates and the inability to adaptively adjust according to the geometry of the workpiece. By introducing a visual scanning module to perform three-dimensional modeling of the workpiece, and performing optimization calculations based on the three-dimensional geometric model with the goal of maximizing and homogenizing irradiance, intelligent adjustment of the posture and power of the radiating plate array is realized. This enables each radiating plate to adopt differentiated strategies such as vertical irradiation, normal alignment irradiation, and multi-directional cross irradiation for the planar areas, curved areas, and concave and inner corner areas of the workpiece, respectively. This effectively solves the problems of uneven irradiance on the surface of complex-shaped workpieces and poor curing in shadow areas.

[0018] This application discretizes the workpiece surface into micro-elements and establishes an optimization objective function and constraints for the irradiance distribution. It then uses high-dimensional nonlinear optimization methods such as genetic algorithms to solve for the optimal tilt angle, azimuth angle, and output power of each radiating plate. This enables the rapid generation of optimal irradiance configuration schemes for workpieces with arbitrarily complex geometries, breaking through the traditional one-size-fits-all curing mode and significantly improving the equipment's adaptability to different workpieces and the consistency of curing quality.

[0019] This application uses a temperature sensor array to monitor the temperature distribution of each area on the workpiece surface in real time, and combines an incremental PID control algorithm to dynamically fine-tune the output power of the radiation plate. This forms a closed-loop control link of visual modeling optimization calculation posture and power adjustment temperature feedback compensation data learning and parameter optimization, ensuring that the temperature deviation of each area is controlled within 3℃ during the curing process, thereby improving the stability and reliability of the coating curing quality.

[0020] This application divides the curing chamber into three independent temperature control modules: a preheating zone, a main curing zone, and a constant-temperature post-curing zone. It combines a synergistic heating mode of catalytic infrared radiation and directional hot air circulation. The heating mode is intelligently switched or superimposed according to different process stages (melting and leveling stage, cross-linking and curing stage) and different workpiece types (thick-walled workpiece mode). This ensures the high efficiency and rapid heating advantage of infrared radiation, while the hot air convection compensates for the insufficient heating of the backlit surface and recessed areas by infrared radiation, thus achieving a balance between heating efficiency and temperature uniformity. Attached Figure Description

[0021] Figure 1 This is a plan view of a low-temperature powder coating and curing device based on gas-fired catalytic infrared radiation, provided as an embodiment of this application.

[0022] Figure 2 This is a schematic diagram of a curing oven for a low-temperature powder coating curing device based on gas-fired catalytic infrared radiation, provided as an embodiment of this application.

[0023] Figure 3This is a schematic diagram of the module connection of a low-temperature powder coating and curing device based on gas-fired catalytic infrared radiation, provided as an embodiment of this application. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments.

[0025] This application provides a low-temperature powder coating and curing device based on gas-fired catalytic infrared radiation, such as... Figures 1-3 As shown, it includes: a curing chamber, a conveying device, a control module, a gas supply module, a zone adjustment module, and a temperature sensor array; The curing chamber is divided into three independent temperature control modules along the conveying direction: a preheating zone, a main curing zone, and a constant temperature post-curing zone. Each module is equipped with a heat insulation partition, and each module is independently configured with a gas catalytic infrared radiation plate and equipped with an independent zone adjustment module and a temperature sensing array. Specifically, the preheating zone is equipped with a first catalytic infrared radiation plate, which is used to raise the surface temperature of the workpiece from room temperature to near the melting temperature of the powder coating, so as to avoid the workpiece being suddenly heated, which would cause coating bubbles or poor leveling. The temperature sensing array in the preheating zone monitors the surface temperature of the workpiece in real time, and the control module adjusts the gas supply to the first catalytic infrared radiation plate to control the temperature of the preheating zone. The main curing zone is equipped with a second catalytic infrared radiation plate and a multi-angle adjustable radiation plate group consisting of multiple catalytic infrared radiation plates. Each radiation plate in the multi-angle adjustable radiation plate group is independently connected through a servo mechanism, and its tilt angle and azimuth angle can be adjusted separately to perform multi-angle radiation curing on the main surface of the workpiece. The temperature is controlled within the optimal curing window of the powder coating. The temperature sensor array in the main curing zone provides real-time temperature feedback, and the control module achieves precise temperature control by adjusting the gas supply of the second catalytic infrared radiation plate. The constant temperature post-curing zone is equipped with a third catalytic infrared radiation plate and a micro-circulation hot air auxiliary module. The constant temperature environment is maintained through the synergistic effect of catalytic infrared radiation and micro-circulation hot air, ensuring that the coating is fully cross-linked and cured, while avoiding coating embrittlement caused by over-curing. The temperature control accuracy of the constant temperature post-curing zone is 2℃. Furthermore, the micro-circulation hot air auxiliary module is set in the constant temperature post-curing zone, including a micro-circulation fan, an electric auxiliary heater, an air duct, and an air distribution plate; The micro circulating fan is installed on the top outer side of the constant temperature curing zone. Its air inlet is connected to the lower side wall of the curing chamber through the return air pipe, and its air outlet is connected to the air inlet of the electric auxiliary heater through the air supply pipe. The air outlet of the electric auxiliary heater is connected to the air distribution plates set on the top and sides of the curing chamber through the air supply branch pipes. The air distribution plate is made of stainless steel plate with several ventilation holes evenly distributed on the plate surface. The diameter of the ventilation holes gradually increases from the center area of ​​the air distribution plate to the edge area to compensate for the wind pressure loss in the edge area and keep the air velocity consistent across the entire width of the air distribution plate. The air distribution plate is installed on the inner wall of the curing chamber via a detachable bracket, facilitating regular disassembly and cleaning and preventing dust from clogging the ventilation holes and affecting the air distribution effect during long-term use. Air distribution plates are installed on the top and side walls of the constant-temperature curing zone, and the three air distribution plates simultaneously deliver air, forming a multi-directional, dead-angle-free micro-circulation airflow field within the curing chamber. The micro circulating fan is driven by a variable frequency speed control motor. The control module adjusts the speed of the micro circulating fan and the power of the electric auxiliary heater in real time based on the temperature distribution data fed back by the temperature sensor array in the constant temperature curing zone, so that the temperature uniformity in the constant temperature curing zone is maintained within 2℃. The micro-circulation hot air auxiliary module starts operating during the cross-linking and curing stage. The hot air temperature is set to a compensation temperature 3-5°C lower than the current curing temperature, and the air volume is set to 30%-50% of the rated air volume of the micro-circulation fan to avoid excessive air volume causing disturbance to the coating surface.

[0026] The first, second, and third catalytic infrared radiation plates are all of the same specification. Temperature differences in different areas are achieved by independently controlling the gas supply and the working status of the radiation plates in each zone. The curing cavity also integrates a visual scanning module and a multi-degree-of-freedom adjustable infrared radiation plate array. The visual scanning module is fixedly installed on the outside of the entrance end of the curing cavity and includes at least one set of binocular structured light 3D cameras and structured light projectors; The binocular structured light 3D camera consists of a left camera and a right camera, used to simultaneously acquire two-dimensional color images and depth images of the workpiece; the structured light projector is used to project coded structured light (preferably Gray code structured light or phase-shifted structured light) onto the workpiece surface to enhance the feature recognition of weak texture areas and low contrast surfaces, and improve the integrity and accuracy of 3D reconstruction. After the visual scanning module has completed the dual-camera calibration in advance (including the intrinsic parameter calibration of the left and right cameras, stereo correction, and the extrinsic parameter calibration between the structured light projector and the camera), it can obtain the three-dimensional coordinates of each point on the workpiece surface in the camera coordinate system and generate three-dimensional point cloud data of the workpiece containing RGB color information and depth information.

[0027] When the workpiece is transported by the conveyor to the scanning station at the front end of the curing chamber entrance, the conveyor pauses or slows down, and the vision scanning module starts scanning. The structured light projector projects coded structured light onto the workpiece surface, and the binocular structured light 3D camera simultaneously acquires left and right image pairs carrying the structured light pattern. The disparity is calculated by the stereo matching algorithm, and the 3D point cloud of the workpiece surface is reconstructed by combining the camera calibration parameters. For workpieces with large size or complex geometry, the vision scanning module can perform segmented scanning or multi-angle scanning along the conveying direction. The point cloud data obtained from multiple scans are then stitched and fused into a complete 3D point cloud model of the workpiece through coarse registration (using the Sample Consistency Initial Registration Algorithm SAC-IA) and fine registration (using the Iterative Closest Point Algorithm ICP). The control module receives the 3D point cloud data generated by the visual scanning module, and generates a digital 3D geometric model of the workpiece through point cloud preprocessing (including filtering and noise reduction, downsampling compression and outlier removal), point cloud segmentation (using Euclidean clustering segmentation or normal-based region growing segmentation algorithm to separate the workpiece point cloud from the background point cloud) and surface reconstruction algorithm. It identifies and stores the geometric contour dimensions of the workpiece, the normal direction of each surface, the curvature distribution characteristics, and the location information of shadow areas such as depressions, interior corners, and steps. The multi-degree-of-freedom adjustable infrared radiation plate array is disposed on the top and / or side walls of the main curing zone, and consists of multiple catalytic infrared radiation plates. Each radiation plate is connected to the mounting bracket of the curing chamber through an independent two-degree-of-freedom or three-degree-of-freedom universal adjustment mechanism. Each universal adjustment mechanism is driven by at least two servo motors and can rotate independently around the horizontal and vertical axes respectively, so as to achieve precise adjustment of the tilt angle and azimuth angle of the radiation plate. In some embodiments, the universal adjustment mechanism also has a translational degree of freedom to slide along the mounting bracket, which can adjust the radiation distance between the radiation plate and the workpiece. Each servo motor is connected to the servo drive module of the control module, and the PLC controller drives each motor to the target position according to the angle command sent by the host computer. Each catalytic infrared radiation plate has an independent proportional regulating valve and flow meter in its gas supply pipeline. The control module independently adjusts the gas supply of each radiation plate according to the target output power of each radiation plate calculated by the host computer through the zone adjustment module to achieve differentiated control of radiation power.

[0028] The control module calculates the optimal irradiation angle and output power of each radiator in the multi-degree-of-freedom adjustable infrared radiator array based on the workpiece's three-dimensional geometric model. The specific method is as follows: Step one involves discretizing each surface of the workpiece's 3D geometric model into several micro-elements. The discretization process employs a curvature-adaptive mesh generation method. For regions with drastic curvature changes (such as arc transition surfaces and interior corner boundaries), the mesh is refined; for planar regions with gentle curvature changes, the mesh density is appropriately relaxed to reduce computational load while maintaining calculation accuracy. For each micro-element, the control module calculates the normal direction vector based on its spatial coordinates and extracts geometric feature parameters such as the micro-element's area, spatial position, and surface curvature. Step 2: Establish the objective function and constraints for the irradiance distribution. Using the current position and orientation of each radiating plate as the initial state, the optimization objective is to maximize the infrared irradiance received by each micro-surface element on the workpiece surface and minimize the irradiance difference between each micro-surface element. Specifically, for any micro-element on the surface of the workpiece, the total irradiance received is equal to the sum of the irradiances of each radiating plate in the array to that micro-element. The irradiance of a single radiating plate to a micro-element is determined by the emission power of the radiating plate, the spatial distance between the radiating plate and the micro-element, the angle between the normal direction of the radiating plate and the normal direction of the micro-element (i.e., the radiation incident angle), and the radiation angle distribution function of the radiating plate. Determining the objective function and constraints is the core step in optimizing the attitude and power of a multi-degree-of-freedom adjustable infrared radiator array. After constructing the three-dimensional geometric model of the workpiece and calculating the normal directions of each micro-surface element, the control module establishes the following optimization mathematical model.

[0029] For the j-th micro-element (j=1,2,,m) obtained after discretizing the workpiece surface, the total irradiance it receives This equals the sum of the irradiance contributed by each radiating plate in the multi-degree-of-freedom adjustable infrared radiating plate array to the micro-area: Where n is the total number of radiating plates. The irradiance of a single radiating plate on a micro-element. The emission characteristics of the radiating plate and the geometric relationship between them are jointly determined: In the formula, Let be the radiant power of the i-th radiating plate; For the radiating plate at the tilt angle and azimuth The radiation directionality coefficient under the catalytic infrared radiation plate characterizes the variation of the radiation intensity of the radiation plate with spatial direction. This coefficient is obtained by conducting a radiation pattern test on the catalytic infrared radiation plate in advance and stored in the database of the control module. The angle coefficient between the surface of the radiating plate and the micro-element is determined by the spatial geometric relationship between the two. The angle between the direction of the line connecting the center of the radiating plate to the micro-facet and the direction of the normal to the micro-facet is the angle of incidence of radiation. The distance is the spatial distance from the center of the radiating plate to the micro-element. The term reflects Lambert's cosine law, which states that irradiance decreases as the angle of incidence increases; The control module takes maximizing the average value of the irradiance of all micro-surface elements as its first objective and minimizing the standard deviation of the irradiance of all micro-surface elements as its second objective, and constructs a comprehensive evaluation function by weighted summation. Define the average value of irradiance for: Define the standard deviation of irradiance for: The expression for the comprehensive evaluation function F is: In the formula, and These are weighting coefficients, representing the importance of maximizing the mean irradiance and ensuring irradiance uniformity, respectively. The values ​​of the weighting coefficients are determined based on the curing process requirements of the powder coating: when the coating is temperature-sensitive and the allowable curing temperature window is narrow, the weighting coefficient is increased. The value should prioritize ensuring uniformity of irradiance; when the coating has a wide curing window and a high tolerance for temperature fluctuations, the value should be appropriately increased. The value of is chosen to prioritize heating efficiency. Preferably, , Prioritizing the uniformity of irradiance. The larger the value of the comprehensive evaluation function F, the better the orientation and power configuration of the radiating plate array. It should be noted that the above objective function can also be equivalently expressed as a minimization form: the objective is to minimize the sum of squares of the differences between the irradiance of each micro-element and the target irradiance. Target irradiance The objective function is calculated using the heat balance equation based on the optimal curing temperature of the powder coating and the workpiece's thermophysical parameters (including specific heat capacity, density, thermal conductivity, and coating thickness). The objective function is then expressed as: The advantage of the minimization form is that it can be solved directly using standard optimization algorithms without the need to select weighting coefficients. The control module provides optional configurations for two objective function forms, which operators can switch between via a human-machine interface according to actual process requirements. The control module applies the following constraints during the optimization process: (a) Tilt angle constraint. The tilt angle of each radiating plate. Limited by the mechanical stroke of the universal adjustment mechanism, the adjustment range is 0–90°. This indicates that the radiating surface of the radiating plate is facing downwards. This indicates that the radiating surface of the radiating plate is vertical. This range ensures that the attitude of the radiating plate can be adjusted throughout the entire half-space from horizontal to vertical; (ii) Azimuth constraint. The azimuth angle of each radiating plate. The adjustment range is -180 to 180. The azimuth angle is defined as the angle between the projection of the normal to the radiating surface of the radiating plate onto the horizontal plane and the conveying direction; a positive value indicates clockwise rotation, and a negative value indicates counterclockwise rotation. This range ensures that the radiating plate can be adjusted omnidirectionally within the horizontal plane. (III) Output Power Constraints. Output power of each radiating plate. Not exceeding its rated power And not lower than the minimum stable operating power : The minimum stable operating power is determined by the catalytic combustion characteristics of the fuel gas in the catalytic infrared radiation plate. When the fuel gas supply is below a certain threshold, the catalytic combustion cannot maintain a self-sustaining reaction, and the radiation plate cannot operate stably. This lower limit is determined experimentally and stored in the control module. (iv) Minimum safe distance constraint between adjacent radiating panels. A minimum safe distance must be maintained between adjacent radiating panels. To avoid mechanical collisions of the radiating plate during attitude adjustment: In the formula, and These are the spatial coordinates of the center points of two adjacent radiating plates. The value of is determined based on the external dimensions of the radiating plate and the motion envelope of the universal adjustment mechanism. Preferably, ; (v) Radiation irradiance limit constraint. The radiation irradiance Ej of each micro-area shall not exceed the maximum safe radiation irradiance allowed by the powder coating. : This constraint is designed to prevent excessively high localized radiation levels from causing the coating temperature to exceed the allowable upper limit, resulting in thermal degradation or over-curing. It was obtained through experimental calibration based on the thermal decomposition temperature and optimal curing temperature of the powder coating. (vi) Constraints on the working state of the radiating plates. Attitude parameters of each radiating plate ( ) and power parameters The combined operating characteristics constraint of the radiating plate must be met, meaning that the maximum allowable output power of the radiating plate in a specific posture is limited by the heat dissipation conditions and gas supply capacity under that posture. This constraint relationship is obtained through thermal characteristic testing of the radiating plate and stored in the control module in the form of a lookup table.

[0030] In summary, the attitude and power optimization problem of a multi-degree-of-freedom tunable infrared radiator array can be fully formulated as a constrained optimization problem in the following form: in, Let be the vector composed of the tilt angles of each radiating plate. This is a vector composed of the azimuth angles of each radiating plate. This is a vector composed of the output power of each radiating plate. Let be the joint working characteristic constraint domain for the ii-th radiating plate. The total number of decision variables in this optimization problem is 3n. As the number of radiating plates increases, the solution space grows exponentially, making it a typical high-dimensional nonlinear constrained optimization problem. Step 3: Using the tilt angle, azimuth angle, and output power of each radiating plate as optimization variables, an optimization algorithm is used to iteratively calculate the optimal attitude and power parameters of each radiating plate. When the workpiece geometry is relatively simple and the number of radiating plates is small, the gradient descent method is used for fast solution. Taking the current attitude of each radiating plate as the initial point, the optimal solution is iteratively searched along the negative gradient direction of the objective function. When the workpiece geometry is complex (e.g., with multiple recesses, interior angles, or irregular curved surfaces) or the number of radiating plates is large, the control module switches to a genetic algorithm for global optimization. The basic flow of the genetic algorithm is as follows: (a) Chromosome Encoding. The parameters to be optimized for each radiator in the multi-degree-of-freedom tunable infrared radiator array are encoded as chromosomes. The parameters to be optimized for each radiator include tilt angle. Azimuth and output power The subscript i represents the radiating plate number, i = 1, 2, ..., n, where n is the total number of radiating plates. Tilt angle The value range is 0 to 90 degrees, azimuth angle The value range is -180 to 180, and the output power is... The value range is 0% to 100% of the rated power of the radiating panel; For each radiating plate, the three parameters mentioned above are encoded using 10-bit binary numbers. The binary codes of the three parameters are concatenated sequentially to form the gene segment of that radiating plate. The gene segments of all n radiating plates are cascaded together to form a complete chromosome, with a total chromosome length of 30n bits. Each chromosome represents a possible orientation and power configuration scheme for the radiating plate array. (II) Initial Population Generation. The control module randomly generates N chromosomes as the initial population. The population size N is set according to the number of radiating plates. Preferably, when n > 10, N = 80; when n > 10, N = 120. Each gene locus in each chromosome is randomly assigned a value of 0 or 1 with equal probability to ensure that the initial population is uniformly distributed in the solution space and to avoid the population from getting trapped in local optima too early. (III) Fitness Function Design. The fitness function is used to evaluate the merits of each configuration scheme. After decoding each chromosome into the corresponding radiation plate tilt angle, azimuth angle, and output power parameters, the control module calculates the radiation distribution received by each micro-surface element on the workpiece surface according to the radiation calculation model; Fitness function of the control module Defined as a monotonically increasing mapping of the comprehensive evaluation function F: In the formula, k is a scaling factor used to map F to the (0,1) interval for easier subsequent selection. The closer the fitness value is to 1, the better the configuration scheme. (iv) Selection Operation. A combination of roulette wheel selection and elite retention strategy is used for individual selection. First, the fitness value of each individual in the current population is calculated, and selection probabilities are allocated according to the proportion of fitness values; individuals with higher fitness have a greater probability of being selected. Simultaneously, an elite retention strategy is employed, selecting the top E individuals with the highest fitness in the current population (elite percentage). The optimal solution is directly copied into the next generation of the population to ensure that it is not lost during evolution. The remaining individuals are randomly selected from the current population using a roulette wheel selection method. (v) Crossover operation. For the two selected parent individuals, crossover is performed with a crossover probability. (Preferred, Single-point or multi-point crossover can be performed. Single-point crossover involves randomly selecting a crossover point within the chromosome length range and exchanging all gene loci after that point on the two parent chromosomes, generating two offspring individuals. Multi-point crossover involves randomly selecting multiple crossover points within the chromosome length range and alternately exchanging gene segments between the two parent chromosomes at each crossover point. For arrays with a large number of radiating plates, multi-point crossover is preferred to enhance gene recombination ability. (vi) Mutation operation. For the offspring generated after crossover, the mutation probability is... (Preferred, Mutation operations are performed on individual gene loci in the chromosome, i.e., randomly flipping selected gene loci (0 becomes 1, 1 becomes 0). Mutation operations help maintain population diversity and prevent the algorithm from prematurely converging to a local optimum. (vii) Convergence determination and iteration termination. Repeat steps (iv) to (vi) until any of the following termination conditions are met: 1. The change in fitness value of the best individual in the population for G consecutive generations (preferably, G=50) is less than a preset threshold. (Preferred, ); 2. The number of iterations reaches the preset maximum number of generations. (Preferred, Once the termination condition is met, the control module outputs the chromosome corresponding to the individual with the highest fitness in the current population, decodes it into the optimal combination of tilt angle, azimuth angle and output power parameters for each radiating plate, and uses it as the final result of the global optimization solution; It should be noted that the parameters of the genetic algorithm (population size n, crossover probability) Probability of mutation Elite rate Maximum number of generations and convergence threshold All parameters can be adjusted online through the human-machine interface of the control module to adapt to workpieces of varying complexity and different numbers of radiant plate array configurations. The control module also records the evolution curve of each optimization process (including the average fitness and optimal fitness of each generation of the population) and displays it in real time on the host computer interface, allowing operators to monitor the optimization process and determine the convergence status. Based on the optimization results, the control module formulates differentiated irradiation strategies for different types of workpiece surfaces: for planar areas of the workpiece, the control radiator plate is irradiated in a direction perpendicular to the irradiated surface, so that the radiant energy is projected onto the surface with the minimum incident angle; for curved areas of the workpiece, the control radiator plate is aligned with the normal direction of each micro-element of the curved surface to achieve normal alignment irradiation; for concave and inner corner areas of the workpiece, multiple radiator plates are irradiated from different directions to ensure that the shaded areas also receive sufficient radiant energy. Step four: The control module converts the calculated optimal tilt and azimuth angles into pulse commands for each servo motor. Specifically, based on the kinematic model of each universal adjustment mechanism, the control module converts the target attitude parameters (tilt and azimuth angles) of the radiating plate into the target rotation angle of each joint servo motor through inverse kinematics calculation. Then, based on the pulse equivalent of the servo motor, the target rotation angle is converted into the corresponding pulse number and pulse frequency, which are output to each servo motor through the servo drive module to drive the universal adjustment mechanism to adjust each radiating plate to the target attitude. Simultaneously, the control module converts the calculated optimal output power into opening commands for each proportional control valve. Specifically, based on the power-gas flow characteristic curve of the catalytic infrared radiating plate, the target power is mapped to the corresponding gas flow setpoint. Then, based on the flow-opening characteristic curve of the proportional control valve, the gas flow setpoint is converted into a valve opening control signal, which is used by the zone adjustment module to adjust the gas supply to each radiating plate. After the radiating plate attitude and power are adjusted, the conveying device restarts, sending the workpiece into the main curing zone for radiation curing.

[0031] During the curing process, the temperature sensor array in the main curing zone monitors the temperature distribution of each area on the workpiece surface in real time. The control module compares the measured temperature distribution with the target temperature distribution and calculates the temperature deviation of each area. When the measured temperature of a certain area deviates from the target value, the control module dynamically fine-tunes the output power of the corresponding radiant plate based on the temperature deviation signal. The fine-tuning amount is calculated using an incremental PID control algorithm. The priority of temperature feedback compensation is set as follows: first, ensure that the highest temperature on the workpiece surface does not exceed the safe upper limit temperature of the powder coating; second, ensure that the temperature deviation of each area from the target temperature is controlled within 3℃. The control module records the attitude parameters, power parameters, and temperature distribution data of each curing process in real time. Through machine learning algorithms, it continuously optimizes the weighting coefficients and algorithm parameters in the objective function, forming a closed-loop control link of visual modeling optimization calculation of attitude and power adjustment temperature feedback compensation data learning and parameter optimization.

[0032] Furthermore, the curing chamber is simultaneously equipped with a catalytic infrared radiation module and a directional hot air circulation module. The catalytic infrared radiation module includes several catalytic infrared radiation plates disposed on the top and / or side walls of the curing chamber. Each radiation plate is connected to the gas supply module through an independent gas supply pipeline. Each pipeline is independently equipped with a proportional regulating valve and a flow meter to regulate the gas supply and radiation power of each radiation plate. The directional hot air circulation module includes a circulating fan and an air duct guide plate. The air inlet of the circulating fan is located at the top or upper side wall of the curing chamber, and the air outlet is connected to several air supply nozzles distributed on the inner wall of the curing chamber through an air duct. The air duct guide plate is located at the air supply nozzles and its angle is adjustable, used to guide hot air to a designated area of ​​the workpiece. A circulating fan drives heated external air to be delivered into the cavity through air nozzles, creating forced convection circulation. The hot air temperature is regulated by an external heating mechanism, and the hot air flow rate is regulated by the speed of the circulating fan. The catalytic infrared radiation module and the directional hot air circulation module share the same control module; they can operate independently or simultaneously.

[0033] The control module intelligently switches between or superimposes two heating modes based on the curing process stage and workpiece type, as detailed below: (i) Melting and leveling stage. When the workpiece passes through the preheating zone and enters the front section of the main curing zone, the powder coating on the workpiece surface has not yet completely melted. At this time, the control module mainly uses catalytic infrared radiation for heating, and catalytic infrared radiation accounts for more than 80% of the total heating power. The directional hot air circulation module is turned off or operates only at a very low air volume (the air volume does not exceed 10% of the rated air volume). During this stage, the mid-to-long-wave infrared radiation generated by the catalytic infrared radiation plate is selectively absorbed by the organic functional groups in the powder coating, causing the coating temperature to rise rapidly to the melting temperature. The powder particles soften, coalesce, and level into a continuous thin film. Because the infrared rays directly heat the coating rather than the intermediate medium, the heating rate is fast, and forced convection does not disturb the coating surface, resulting in a smooth and even paint film appearance. Simultaneously, the control module keeps the directional hot air circulation module in standby mode (powered on but maintained at a standby temperature 20-30°C below the operating temperature) to ensure a rapid response when switching to the hybrid mode. (II) Crosslinking and Curing Stage. When the workpiece enters the latter part of the main curing zone and the constant-temperature post-curing zone, the powder coating has completed melt leveling and enters the crosslinking and curing stage. At this time, the control module switches to a hybrid heating mode of catalytic infrared radiation + micro-circulating hot air. Catalytic infrared radiation continues to provide the activation energy required for the coating crosslinking reaction, maintaining the coating temperature within the curing window; The micro-circulation hot air auxiliary module starts operating, with the hot air temperature set to a compensation temperature 3-5℃ lower than the current curing temperature, and the air volume set to 30%-50% of the rated air volume. The hot air transfers heat to areas of the workpiece that are difficult to be directly irradiated by infrared radiation, such as the back surface, recesses, and inner corners, through forced convection, eliminating local temperature differences caused by the complex geometry of the workpiece. At the same time, the hot air circulation agitates the air in the cavity, making the temperature field in all areas of the cavity more uniform. The control module dynamically adjusts the output power of the directional hot air circulation module and the speed of the circulating fan based on the temperature signals of each area fed back by the temperature sensor array, so that the temperature deviation of each area is controlled within 3℃. (iii) Thick-walled workpiece mode. When the vision scanning module identifies that the ratio of the workpiece's volume to its surface area is large (i.e., the heat capacity is large), the control module automatically identifies it as a thick-walled workpiece and switches to the thick-walled workpiece mode; In this mode, single infrared radiation heating can easily cause the surface layer of the workpiece to rapidly rise to the curing temperature while the internal temperature remains low. The surface coating may over-cur due to excessive temperature, while the internal coating may not cure completely due to insufficient temperature. The control module further increases the heating power of the directional hot air circulation module based on the cross-linking curing stage, ensuring that hot air convection accounts for 30%–50% of the total heating power. Hot air conducts heat from the workpiece surface to the interior via convection, compensating for the deficiency of infrared radiation, which only heats the surface and fails to reach the internal temperature. The hot air temperature is set to be the same as or slightly higher than the current curing temperature (not exceeding 5°C), and the airflow is set to 60%–80% of the rated airflow to enhance convective heat transfer. The control module monitors the workpiece surface temperature and the cavity ambient temperature in real time. When the workpiece surface temperature reaches the upper limit of the curing window, the infrared radiation power is reduced first; when the internal temperature of the workpiece (calculated by an infrared temperature sensor based on the thermal radiation signal from a certain depth below the workpiece surface) is lower than the target temperature, the hot air convection power is increased first.

[0034] When the control module switches between different heating modes, it adopts a gradual transition strategy to avoid temperature shocks caused by sudden power changes. Specifically, when switching from the melt leveling stage to the cross-linking and curing stage, the infrared radiation power decreases at a rate not exceeding 5% of the rated power per minute, while the hot air power increases at a rate not exceeding 10% of the rated power per minute, with a transition time of 30 to 60 seconds. In the thick-walled workpiece mode, power distribution employs closed-loop regulation: the control module aims to minimize the difference between the highest and lowest temperatures on the workpiece surface, using the ratio of infrared radiation power to hot air convection power as the operating variable, and adjusts the power distribution ratio in real time via a PID controller. The control module also records the optimal power distribution parameters for each workpiece type under each heating mode, forming a process parameter library. For workpieces in the same batch or of the same type, historical optimal parameters can be directly retrieved without recalculation.

[0035] Furthermore, the human-machine interface of the control module provides a manual switching option for the heating mode. Operators can force the current heating mode to be specified or manually adjust the power distribution ratio between infrared radiation and hot air convection according to actual process requirements. The control module is also equipped with safety protection logic: when the gas concentration detection value of the catalytic infrared radiation module exceeds the safety threshold, the control module automatically cuts off the gas supply and switches to pure hot air heating mode. When the temperature of the electric heater in the directional hot air circulation module exceeds the safety limit, the control module automatically cuts off the power supply to the electric heater and switches to pure infrared radiation mode. When both heating modules malfunction, the control module issues an audible and visual alarm and stops the conveyor system.

[0036] The conveying device adopts a closed-loop electric continuously variable speed chain conveying module, including a drive motor, worm gear reducer, drive sprocket, driven sprocket, closed-loop chain and suspension mechanism; The drive motor is a variable frequency speed control motor, whose output shaft is connected to the input shaft of a worm gear reducer. The output shaft of the worm gear reducer is connected to the driving sprocket. A closed-loop chain is wound between the driving sprocket and the driven sprocket. The workpiece is connected to the closed-loop chain via a suspension mechanism and moves with the chain. The drive motor is driven by a frequency converter, and the control module achieves stepless adjustment of the conveying speed by adjusting the output frequency of the frequency converter. The preferred speed range is 1.5m / min to 8m / min. The suspension mechanism includes a hook, a rotary joint, and a hanger. The workpiece is fixed on the hanger, and the hanger is connected to the lower end of the hook through the rotary joint. The upper end of the hook is fixed to a link of a closed-loop chain. The workpiece can rotate freely around the vertical axis while moving horizontally with the chain, which is beneficial for the uniform irradiation of the circumferential surface of the workpiece by infrared radiation. The control module extracts the geometric dimensions (including length, width, height and maximum projected area) of the workpiece based on the three-dimensional geometric model established by the vision scanning module, and obtains its specific heat capacity, density and thermal conductivity and other thermal property parameters based on the workpiece material (such as steel, aluminum, cast iron, etc.) by looking up a table. Combined with the recommended curing temperature curve of the powder coating (including melting temperature, curing temperature and holding time), the module calculates the required residence time of the workpiece in each temperature zone. Specifically, the control module calculates the required residence time in the preheating zone based on the workpiece's heat capacity (calculated by the product of volume and specific heat capacity) and the radiant power density of the preheating zone; it calculates the required residence time in the main curing zone based on the curing kinetic parameters of the powder coating and the radiant power density of the main curing zone; and it calculates the required residence time in the isothermal curing zone based on the crosslinking reaction rate constant of the powder coating and the temperature setpoint of the isothermal curing zone. The control module divides the required residence time in each temperature zone by the length of the corresponding zone to obtain the theoretical conveying speed required for each zone. The minimum of these three values ​​is then taken as the final set conveying speed to ensure that the actual residence time of the workpiece in each temperature zone meets the process requirements. The control module also automatically adjusts the conveying speed based on the number of workpieces in the same batch. When conveying multiple workpieces continuously, the control module appropriately reduces the conveying speed to ensure sufficient safe distance between adjacent workpieces and prevent collisions within the curing chamber.

[0037] The temperature sensing array includes two types: infrared temperature sensors and contact thermocouples, which are arranged in a coordinated manner within each temperature control module. The infrared temperature sensors are thermopile-type non-contact infrared temperature sensors, installed on the top and side walls of each temperature control module. Their field of view covers the entire surface area of ​​the workpiece in each temperature zone. The number of infrared temperature sensors is determined according to the length and width of the temperature control module. At least six infrared temperature sensors are independently configured in the preheating zone, main curing zone, and constant temperature post-curing zone, evenly distributed along the conveying direction and width direction to form a temperature measurement grid. Each sensor independently measures the radiation temperature of the workpiece surface within its corresponding field of view and transmits the temperature signal to the control module through the analog input module. The infrared temperature sensor uses the 8m to 14m band for temperature measurement. This band partially overlaps with the 3.5m to 8m radiation band emitted by the catalytic infrared radiation plate. The control module corrects the reading of the infrared temperature sensor through a preset emissivity compensation algorithm to eliminate the interference of catalytic infrared radiation on the temperature measurement accuracy. The contact thermocouples are type K, installed on the back of each catalytic infrared radiation plate (for measuring the surface temperature of the radiation plate) and on the inner wall of the curing chamber (for measuring the ambient temperature). Cold junction compensation of the thermocouples is achieved automatically using an internal temperature sensor. The control module uses the workpiece surface temperature measured by the infrared temperature sensor as the primary control variable, and the radiation plate surface temperature and ambient temperature measured by the contact thermocouples as auxiliary monitoring variables. When the workpiece surface temperature fed back by the infrared temperature sensor in a certain temperature zone deviates from the target temperature, the control module first determines the source of the deviation: if the surface temperature of the radiation plate is normal but the surface temperature of the workpiece is low, it indicates that there is an obstruction in the radiation heat transfer path between the radiation plate and the workpiece or the workpiece has a large heat capacity. At this time, the control module extends the residence time of the workpiece in that temperature zone or increases the heating power of the subsequent temperature zones to compensate. If the surface temperature of the radiant panel is too low, the control module increases the gas supply to the panel to improve its radiation power. The control module records the temperature data of each measuring point in real time and generates a temperature distribution cloud map, which is displayed on the host computer interface for operators to monitor the temperature uniformity of each temperature zone.

[0038] The inner wall of the curing chamber is provided with an infrared reflective layer, which covers the entire inner wall surface of the preheating zone, the main curing zone and the constant temperature post-curing zone, including the top, bottom, side walls and the surface of the insulation partition between each temperature zone.

[0039] The infrared reflective layer is made of a high-infrared-reflectivity metallic material, preferably polished aluminum or gold-plated copper. Polished aluminum achieves an infrared reflectivity of over 85% in the 3.5m–8m wavelength range, while gold-plated copper achieves over 95% in the same range. Considering cost, polished aluminum is preferred as the infrared reflective layer material. The infrared reflective layer is fixed to the inner wall surface of the curing chamber in a plate-like form. The seams between the reflective plates are overlapped to prevent heat leakage. The surface of the infrared reflective layer is mirror-polished with a roughness Ra of no more than 0.8 μm to ensure maximum infrared reflection efficiency. The setting angle of the infrared reflective layer is optimized according to the geometry of the curing cavity and the installation position of the radiation plate: the top reflective layer of the curing cavity adopts a planar structure to reflect the infrared radiation emitted upward by the radiation plate back to the upper surface of the workpiece. For the reflective layers on both sides of the curing cavity, an arc or parabolic surface structure is adopted to focus and reflect the infrared radiation emitted laterally by the radiation plate to the side, recess and inner corner areas of the workpiece. The bottom reflective layer of the curing cavity adopts a planar structure to reflect the radiant energy passing through the gap between the workpieces to the bottom and back of the workpiece. The infrared reflective layer improves the utilization efficiency of infrared radiation, reduces heat loss caused by the absorption of radiation energy by the inner wall of the curing cavity, and allows more radiation energy to be projected onto the surface of the workpiece. On the other hand, through multiple reflections, the radiant energy is guided to the backlight and shadow areas that cannot be directly illuminated by the radiant plate, thereby improving the uniformity of irradiance on each surface of the complex-shaped workpiece. An insulation layer is also installed on the outer side of the infrared reflective layer (i.e., the side closest to the outer wall of the curing chamber). This insulation layer, made of aluminum silicate fiber cotton or aerogel felt, is 50mm–100mm thick and is used to reduce heat loss from the curing chamber to the environment through the outer wall, further reducing energy consumption. During use, the reflectivity of the infrared reflective layer may decrease due to dust accumulation. Therefore, an openable inspection door is installed at the bottom or on the side wall of the curing chamber. Operators can use this door to periodically clean and maintain the surface of the infrared reflective layer to restore its reflective performance.

[0040] In one embodiment, a computer-readable storage medium is also provided, having a computer program stored thereon that, when executed by a processor, performs the following steps: Acquire the 3D point cloud data generated by the vision scanning module after scanning the workpiece in 3D; The three-dimensional point cloud data is processed by point cloud processing and surface reconstruction to generate a three-dimensional geometric model of the workpiece. Based on the three-dimensional geometric model, with the optimization objective of maximizing the infrared radiation irradiance received by each region of the workpiece surface and uniformizing the radiation irradiance distribution, the target tilt angle, target azimuth angle and target output power of each radiation plate in the multi-degree-of-freedom adjustable infrared radiation plate array are calculated. The servo motor is driven according to the target tilt angle and the target azimuth angle to adjust each radiating plate to the target attitude, and the gas supply of each radiating plate is adjusted by the partition adjustment module according to the target output power.

[0041] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A low-temperature powder coating and curing device based on gas-fired catalytic infrared radiation, characterized in that, include: Solidification chamber, conveying device, control module, gas supply module, zone regulation module and temperature sensor array; The curing chamber is divided into a preheating zone, a main curing zone and a constant temperature post-curing zone along the conveying direction, and each zone is independently equipped with a catalytic infrared radiation plate. The main curing zone is equipped with a multi-degree-of-freedom adjustable infrared radiation plate array, which consists of multiple catalytic infrared radiation plates. Each radiation plate is connected to the mounting bracket of the curing cavity through an independent universal adjustment mechanism. The universal adjustment mechanism is driven by a servo motor and can adjust the tilt angle and azimuth angle of each radiation plate. A vision scanning module is fixedly installed on the outside of the inlet end of the curing cavity. The vision scanning module is used to perform three-dimensional scanning of the workpiece and generate three-dimensional point cloud data of the workpiece. The control module receives the three-dimensional point cloud data generated by the visual scanning module, and generates a three-dimensional geometric model of the workpiece through point cloud processing and surface reconstruction. Based on the three-dimensional geometric model, the control module calculates the target tilt angle, target azimuth angle and target output power of each radiating plate in the multi-degree-of-freedom adjustable infrared radiating plate array with the optimization objective of maximizing the infrared irradiance received by each region of the workpiece surface and uniformizing the irradiance distribution. The control module drives the servo motor according to the calculated target tilt angle and target azimuth angle to adjust each radiating plate to the target attitude, and adjusts the gas supply of each radiating plate through the partition adjustment module according to the target output power.

2. The low-temperature powder coating and curing equipment based on gas-fired catalytic infrared radiation according to claim 1, characterized in that, The control module establishes the following optimization objective function: The surface of the three-dimensional geometric model is discretized into several micro-surface elements. For the j-th micro-surface element, the total irradiance it receives is... It equals the sum of the irradiance contributed by each radiating plate to the micro-element: Where n is the total number of radiating plates, and the irradiance of a single radiating plate on a micro-element is... Determined by the following formula: In the formula, Let be the radiant power of the i-th radiating plate. and Let be the tilt angle and azimuth angle of the i-th radiating plate, respectively. The radiation directivity coefficient, The angle coefficient, For the incident angle of radiation, The spatial distance from the center of the radiating plate to the micro-facet element; The control module uses the average irradiance of all micro-facets. Maximize and standard deviation Minimize as the optimization objective, construct a comprehensive evaluation function: in, and These are weighting coefficients. , , where m is the total number of micro-surface elements.

3. The low-temperature powder coating and curing equipment based on gas-fired catalytic infrared radiation according to claim 2, characterized in that, The control module uses the tilt angle of each radiating plate Azimuth and output power To optimize the variables, solve the following constrained optimization problem: The constraints include: Tilt angle constraint: ; Azimuth constraint: ; Output power constraint: ,in For minimum stable operating power, Rated power; Minimum safe distance constraint between adjacent radiating panels: ,in and These are the spatial coordinates of the center points of two adjacent radiating plates. Minimum safe distance; Radiation irradiance upper limit constraint: ,in This represents the maximum permissible safe irradiance for powder coatings. And constraints on the combined working characteristics of the radiating plates: ,in Let be the joint operating characteristic constraint domain for the i-th radiating plate.

4. The low-temperature powder coating and curing equipment based on gas-fired catalytic infrared radiation according to claim 3, characterized in that, When the workpiece geometry is complex or the number of radiating plates exceeds a preset threshold, the control module uses a genetic algorithm to solve the constraint optimization problem. (a) Chromosome encoding: The tilt angle of each radiating plate Azimuth and output power Encoded as binary chromosomes, each chromosome represents a pose and power configuration scheme for the radiating plate array; (ii) Initial population generation: N chromosomes are randomly generated as the initial population; (III) Fitness function design: Each chromosome is decoded into corresponding attitude parameters and power parameters. The irradiance distribution of each micro-element is calculated according to the irradiance calculation model. The monotonically increasing mapping of the comprehensive evaluation function F is used as the fitness function. (iv) Selection operation: Individuals are selected for the next generation of the population by combining roulette wheel selection with an elite retention strategy; (v) Crossover operation: based on crossover probability Crossover operations are performed on the selected parent individuals to generate offspring individuals; (vi) Mutation operation: based on mutation probability Perform mutation operations on gene loci in offspring individuals; (vii) Iteration termination judgment: Repeat steps (iv) to (vi) until the termination condition is met, and output the attitude parameters and power parameters corresponding to the individual with the highest fitness as the optimization result.

5. The low-temperature powder coating and curing equipment based on gas-fired catalytic infrared radiation according to claim 1, characterized in that, The control module converts the target tilt angle and the target azimuth angle into the target rotation angle of each servo motor through inverse kinematics calculation, and then converts the target rotation angle into a pulse command according to the pulse equivalent of the servo motor and outputs it to each servo motor to drive the universal adjustment mechanism to adjust each radiating plate to the target attitude. The control module converts the target output power into a gas flow setpoint based on the power-gas flow characteristic curve of the catalytic infrared radiation plate, and then converts the gas flow setpoint into a valve opening control signal based on the flow-opening characteristic curve of the proportional regulating valve, which is then output to the zone regulating module.

6. The low-temperature powder coating and curing equipment based on gas-fired catalytic infrared radiation according to claim 1, characterized in that, The visual scanning module includes at least one set of binocular structured light 3D cameras and a structured light projector. The binocular structured light 3D camera consists of a left camera and a right camera. The structured light projector is used to project coded structured light onto the surface of the workpiece. After binocular calibration, the visual scanning module synchronously acquires left and right image pairs carrying structured light patterns through the binocular structured light 3D camera. The disparity is calculated by the stereo matching algorithm, and the 3D point cloud of the workpiece surface is reconstructed by combining the camera calibration parameters. For workpieces larger than the preset size or with complex geometry, the vision scanning module performs segmented scanning or multi-angle scanning of the workpiece along the conveying direction, and the point cloud data obtained from multiple scans are spliced ​​and fused into a complete three-dimensional point cloud of the workpiece through coarse registration and fine registration. The control module sequentially performs filtering and noise reduction, downsampling compression, outlier removal, point cloud segmentation, and surface reconstruction on the three-dimensional point cloud to generate the three-dimensional geometric model, and identifies the geometric contour dimensions of the workpiece, the normal direction of each surface, the curvature distribution characteristics, and the location information of the shadow area.

7. The low-temperature powder coating and curing equipment based on gas-fired catalytic infrared radiation according to claim 1, characterized in that, The temperature sensing array monitors the temperature distribution in various areas of the workpiece surface in real time and feeds back the measured temperature distribution to the control module. The control module compares the measured temperature distribution with the target temperature distribution. When the measured temperature of a certain area deviates from the target value, the control module dynamically fine-tunes the output power of the radiant panel corresponding to that area based on the temperature deviation signal. The fine-tuning amount is calculated using an incremental PID control algorithm. The control module records the attitude parameters, power parameters, and temperature distribution data for each curing process, and optimizes the weighting coefficients in the objective function using machine learning algorithms.

8. The low-temperature powder coating and curing equipment based on gas-fired catalytic infrared radiation according to claim 1, characterized in that, The curing chamber is also equipped with a directional hot air circulation module, which includes a circulating fan and an air duct guide plate. The air inlet of the circulating fan is located at the top or upper side wall of the curing chamber, and the air outlet is connected to a plurality of air supply nozzles distributed on the inner wall of the curing chamber through an air duct. The air duct guide plate is located at the air supply nozzles and its angle is adjustable. The catalytic infrared radiation plate and the directional hot air circulation module share the same control module, and the two can operate independently or simultaneously. The control module switches the heating mode according to the curing process stage: During the melting and leveling stage, heating is mainly carried out by catalytic infrared radiation, which accounts for more than 80% of the total heating power. The directional hot air circulation module is turned off or operates at less than 10% of the rated air volume. During the cross-linking and curing stage, the system switches to a mixed heating mode of catalytic infrared radiation and micro-circulation hot air. The hot air temperature is set to a compensation temperature that is 3 to 5 degrees Celsius lower than the current curing temperature, and the air volume is set to 30% to 50% of the rated air volume.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it performs the following steps: Acquire the 3D point cloud data generated by the vision scanning module after scanning the workpiece in 3D; The three-dimensional point cloud data is processed by point cloud processing and surface reconstruction to generate a three-dimensional geometric model of the workpiece. Based on the three-dimensional geometric model, with the optimization objective of maximizing the infrared radiation irradiance received by each region of the workpiece surface and uniformizing the radiation irradiance distribution, the target tilt angle, target azimuth angle and target output power of each radiation plate in the multi-degree-of-freedom adjustable infrared radiation plate array are calculated. The servo motor is driven according to the target tilt angle and the target azimuth angle to adjust each radiating plate to the target attitude, and the gas supply of each radiating plate is adjusted by the partition adjustment module according to the target output power.

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