A high-speed signal multivariable control method, device and storage medium

Abstract

The application discloses a high-speed signal multivariable control method and device and a storage medium, relates to the technical field of laser metal forming, and is used for solving the problems of poor control precision and low data processing efficiency caused by the fact that feedback control only controls a single variable in the prior art. The application is applied to a high-speed signal multivariable control system, and the system comprises a high-speed camera, a high-speed processing module, a multivariable feedback controller, an industrial computer and a slave device. The molten pool image collected by the high-speed camera is processed by the high-speed processing module to obtain high-frequency molten pool characteristic information. The multivariable feedback controller calculates the target controller parameter of the system based on the high-frequency molten pool characteristic information. The industrial computer controls the corresponding slave device based on the parameter. The application performs multivariable control based on the multivariable feedback controller, improves the data acquisition and processing efficiency, can sensitively capture the slight deviation in the forming process and timely correct the deviation, improves the control precision, and ensures the forming quality of the metal parts.

Description

Technical Field

[0001] This invention relates to the field of laser metal forming technology, and in particular to a high-speed signal multivariable control method, device and storage medium. Background Technology

[0002] Existing laser metal forming technologies generally suffer from a lack of feedback control or ineffective feedback control, leading to heat accumulation, porosity, humps, and dents during the forming process. These adverse effects result in defects such as poor shape accuracy and surface quality. Laser metal forming technology demands high precision from the formed parts; even minute deviations can significantly impact its performance and practical applications.

[0003] Furthermore, given the drastic changes in the molten pool during laser metal forming, real-time monitoring is crucial, requiring sufficiently fast and precise response speeds for feedback control. Existing feedback control technologies typically only address single variables, resulting in poor accuracy and low data processing efficiency.

[0004] Therefore, there is an urgent need to provide a more reliable high-speed signal multivariable control scheme. Summary of the Invention

[0005] The purpose of this invention is to provide a high-speed signal multivariable control method, device, and storage medium to solve the problems of feedback control in the prior art, which can only control a single variable, has poor control accuracy, and low data processing efficiency.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a high-speed signal multivariable control method, which is applied to a high-speed signal multivariable control system. The hardware part of the high-speed signal multivariable control system includes a high-speed camera, an industrial computer, and slave devices. The software part of the high-speed signal multivariable control system includes a high-speed processing module and a multivariable feedback controller.

[0008] The high-speed signal multivariable control method includes:

[0009] Acquire the molten pool image captured at high speed by the high-speed camera;

[0010] The high-speed processing module is used to process the molten pool image to obtain high-frequency molten pool feature information;

[0011] The high-frequency molten pool characteristic information is sent to the multivariable feedback controller, which calculates the target controller parameters of the correction system based on the high-frequency molten pool characteristic information.

[0012] The target controller parameters are sent to the industrial computer, and the industrial computer controls the corresponding slave device to work based on the target controller parameters.

[0013] Compared with existing technologies, the high-speed signal multivariable control method provided by this invention is applied to a high-speed signal multivariable control system. The hardware component of the high-speed signal multivariable control system includes a high-speed camera, an industrial computer, and slave devices. The software component includes a high-speed processing module and a multivariable feedback controller. The method involves acquiring high-speed images of the molten pool from the high-speed camera; processing the molten pool and melt flow images using the high-speed processing module to obtain high-frequency molten pool feature information; sending the high-frequency molten pool and melt flow feature information to the multivariable feedback controller; calculating the target controller parameters for the corrected system based on the high-frequency molten pool and melt flow feature information; and sending the target controller parameters to the industrial computer, which then controls the corresponding slave devices based on the target controller parameters. This invention, based on a multivariable feedback controller for multivariable control, can significantly improve data acquisition and processing efficiency, accurately capture and correct minute deviations during the forming process, improve control precision, and ensure the forming quality of metal parts.

[0014] Secondly, the present invention provides a high-speed signal multivariable control device, which is applied to a high-speed signal multivariable control system. The hardware part of the high-speed signal multivariable control system includes a high-speed camera, an industrial computer, and slave devices. The software part of the high-speed signal multivariable control system includes a high-speed processing module and a multivariable feedback controller.

[0015] The high-speed signal multivariable control device includes:

[0016] A communication unit / communication interface is used to acquire the molten pool image acquired at high speed by the high-speed camera;

[0017] A processing unit / processor is used to process the molten pool image using the high-speed processing module to obtain high-frequency molten pool feature information;

[0018] The high-frequency molten pool characteristic information is sent to the multivariable feedback controller, which calculates the target controller parameters of the correction system based on the high-frequency molten pool characteristic information.

[0019] The target controller parameters are sent to the industrial computer, and the industrial computer controls the corresponding slave device to work based on the target controller parameters.

[0020] Thirdly, the present invention provides a computer storage medium storing instructions that, when executed, implement the above-described high-speed signal multivariable control method.

[0021] The technical effects achieved by the device-type solutions provided in the second aspect and the computer storage medium solutions provided in the third aspect are the same as those achieved by the method-type solutions provided in the first aspect, and will not be repeated here. Attached Figure Description

[0022] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0023] Figure 1 A schematic diagram of a high-speed signal multivariable control system provided by the present invention;

[0024] Figure 2 This is a schematic flowchart of the high-speed signal multivariable control method provided by the present invention;

[0025] Figure 3 The state space diagram of the laser metal forming process parameter variables provided by the present invention;

[0026] Figure 4 This is a schematic diagram of the high-speed signal multivariable control device provided by the present invention. Detailed Implementation

[0027] To facilitate a clear description of the technical solutions in the embodiments of the present invention, the terms "first" and "second" are used to distinguish identical or similar items with essentially the same function and effect. For example, the first threshold and the second threshold are merely used to distinguish different thresholds and do not limit their order. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that the terms "first" and "second" are not necessarily different.

[0028] It should be noted that in this invention, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0029] In this invention, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, a combination of a and b, a combination of a and c, a combination of b and c, or a, b, and c, where a, b, and c can be single or multiple.

[0030] Given the drastic changes in the molten pool during laser metal forming, real-time monitoring is crucial, requiring sufficiently fast response speeds for feedback control. The challenges of real-time control stem primarily from two aspects: the control system's computational speed and communication lag. Computational speed refers to the time spent on data acquisition, processing, and related control calculations per unit of time, while communication lag refers to the delays caused by communication between devices.

[0031] In actual laser metal forming processes, the molten pool is a key variable, and most studies focus on systematic feedback control of its partial morphological features. However, most existing feedback controls utilize Modbus bus technology. Due to the limitation of Modbus write intervals, its data transmission rate is low, only around 30Hz. Meanwhile, the scanning line speed in laser metal forming technology is in the range of 0.5-20m / min. Clearly, the low-frequency transmission of controller parameters cannot meet the real-time control requirements of laser metal forming.

[0032] On the other hand, due to the lack of perfection of the feedback control system, the existing feedback control can only control a single variable. The ability of single-variable control to adjust the morphology of the molten pool or melt channel is very limited. Therefore, even if a closed-loop control strategy is adopted, the final molding accuracy still cannot reach the ideal level.

[0033] To address the aforementioned shortcomings, this invention proposes a high-speed signal multivariate control method, device, and storage medium. Through this high-speed signal multivariate control system, the data acquisition frequency can be increased to over 5kHz, and the feedback control frequency reaches over 1000Hz, enabling it to sensitively capture and promptly correct minute deviations during the molding process. Furthermore, an EtherCAT bus is incorporated to improve communication speed between devices. Based on this, through an optimized matching model of process parameters, multivariate correlation control can be achieved in conjunction with the controller's built-in database. This can be practically applied to the molding of complex parts such as irregular curved surfaces, significantly improving printing accuracy and quality.

[0034] Next, the solutions provided in the embodiments of this specification will be described in conjunction with the accompanying drawings:

[0035] like Figure 1 As shown, the hardware of the high-speed signal multivariable control system includes a high-speed camera, an industrial computer, and slave devices. The high-speed camera may include a coaxial high-speed camera and a lateral high-speed camera. The coaxial high-speed camera is used to acquire images of the molten pool topography at high speed, and the lateral high-speed camera is used to acquire images of the molten channel at high speed. Figure 1 The dashed box in the diagram represents the software portion of the system, which includes a high-speed processing module and a multivariable feedback controller. Images of the molten pool and runner acquired by the high-speed camera are transmitted to the high-speed processing module. Based on these images, the high-speed processing module uses image algorithms to determine the high-frequency molten pool and runner characteristic information. This high-speed processing module then transmits the high-frequency molten pool and runner characteristic information to the multivariable feedback controller, which performs multivariable-to-univariable control based on the received information. Since the multivariable feedback controller also integrates a PID database, it can calculate the optimal controller parameter range based on past print data. The corrected parameters calculated by the multivariable feedback controller are transmitted to the industrial control computer, which controls the operation of each slave device based on these corrected parameters. Slave devices can include lasers, motion controllers, feeding devices, and atmosphere protection systems, etc.

[0036] In this high-speed signal multivariable control system, all components are connected via an EtherCAT bus to achieve high-speed data transmission. Using EtherCAT bus technology, the acquired and processed high-frequency molten pool and melt channel characteristic values ​​are fed into the feedback controller as the control object. The controller calculates and corrects the optimal parameters of the system, which are then transmitted to the industrial computer and, via EtherCAT bus technology, are transmitted at high speed to the connected EtherCAT coupler module. A simplified multivariable control strategy ensures stable layer-by-layer forming of the workpiece. This solution offers high communication efficiency and excellent control precision, meeting the real-time control requirements of laser metal forming.

[0037] based on Figure 1 The present invention also provides a system for... Figure 1 The following section describes the high-speed signal multivariable control method for medium-speed systems:

[0038] like Figure 2 As shown, the method flow may include the following steps:

[0039] Step 210: Obtain the molten pool image acquired at high speed by the high-speed camera.

[0040] High-speed cameras are a type of industrial camera, typically digital industrial cameras, and are a key component of machine vision systems. Their core function is to convert light signals into ordered electrical signals; that is, to capture a target digitally, convert it into an image signal, and transmit it to a dedicated image processing module. High-speed cameras can achieve image sampling rates of several thousand frames per second, offering advantages over ordinary cameras in terms of image stability, transmission capability, and anti-interference ability.

[0041] Given the dramatic changes in the molten pool during laser metal forming, real-time monitoring is crucial. Therefore, a high-speed camera is needed to acquire molten pool images at high speed, improving image data processing and control rates while simultaneously monitoring the molten pool and melt flow path. The molten pool image includes both the molten pool morphology image and the melt flow path image. High-frequency molten pool feature information includes at least the molten pool width and melt flow path height.

[0042] Step 220: The high-speed processing module is used to process the molten pool image to obtain high-frequency molten pool feature information.

[0043] The high-speed processing module can perform shape fitting, ROI region extraction, feature recognition, and CUDA acceleration on the molten pool image acquired by the high-speed camera. After processing, high-frequency molten pool feature information is obtained, which can be feature data such as molten pool width and molten channel height.

[0044] Step 230: The high-frequency molten pool feature information is sent to the multivariable feedback controller, which calculates the target controller parameters of the correction system based on the high-frequency molten pool feature information.

[0045] The multivariable feedback controller in this step can control multiple variables, whereas existing feedback controls can only control a single variable. Compared to existing technologies, the multivariable feedback controller in this invention can simultaneously control the parameters of multiple slave devices during laser metal forming, achieving multi-dimensional real-time control of laser metal forming. The multivariable feedback controller can calculate the target controller parameters of each slave device in the system based on high-frequency molten pool characteristic information, thereby correcting the corresponding characteristic information affected by these parameters.

[0046] Step 240: Send the target controller parameters to the industrial computer, and the industrial computer controls the corresponding slave device to work based on the target controller parameters.

[0047] The multivariable feedback controller and the industrial computer can transmit data via EtherCAT bus. The industrial computer can control the corresponding slave device to operate with appropriate parameters. For example, when the slave device is a laser, the industrial computer can adjust the laser power of the laser; when the slave device is a motion controller, the industrial computer can control the feed speed of the laser cladding head of the motion controller.

[0048] As one implementation method, the high-speed signal multivariable control system may further include:

[0049] EtherCAT master and slave stations;

[0050] The equipment includes at least a laser, a motion controller, a feeding device, and an atmosphere protection system;

[0051] The master station is an industrial control computer that controls slave devices such as lasers and motion controllers by regulating the parameter transmission of slave stations. The slave station is an EtherCAT coupler, which includes an EtherCAT communication interface and I / O terminals. The EtherCAT communication interface is connected to the slave station through a physical layer chip and a network transformer to realize EtherCAT communication between the master station and the slave station. The control signals are directly connected to the slave devices through the I / O terminals.

[0052] When an industrial control computer (ICC) controls slave devices, it employs EtherCAT bus technology. This requires establishing a master station and slave stations. The ICC, equipped with control software, acts as the master station, regulating the slave station's EtherCAT coupler to transmit parameters for controlling devices such as lasers, motion controllers, feeding devices, and atmosphere protection systems. The slave station's EtherCAT coupler has two EtherCAT communication interfaces, both using the standard Ethernet communication interface MII. The MII interface needs to be connected to an RJ4_5 interface via a physical layer PHY chip and a network transformer to achieve EtherCAT communication between the master and slave stations.

[0053] Figure 2The method described above is applied to a high-speed signal multivariable control system. The hardware includes a high-speed camera, an industrial computer, and various slave devices such as a laser, motion controller, and feeding device. The software includes a high-speed processing module and a multivariable feedback controller. The system acquires high-speed images of the molten pool using the high-speed camera; processes the molten pool and melt path images using the high-speed processing module to obtain high-frequency molten pool feature information; sends this feature information to the multivariable feedback controller, calculates the target controller parameters for the correction system based on the feature information, and sends the target controller parameters to the industrial computer, which then controls the corresponding slave devices based on these parameters. This invention uses a multivariable feedback controller for multivariable control, significantly improving data acquisition and processing efficiency, enabling it to accurately detect and correct minute deviations during the forming process, thus improving control precision and ensuring the quality of metal parts forming.

[0054] based on Figure 2 In addition to the method described herein, this specification also provides some specific implementation methods of this method, which will be described below.

[0055] Regarding step 210, before the start of single-feedback control, a coaxial high-speed camera captures the real-time morphology of the molten pool, a rangefinder high-speed camera monitors the molten runner formation process, and image algorithms are used to acquire feature data such as molten pool width and molten runner height. Since the high-speed camera may include both a coaxial high-speed camera and a rangefinder high-speed camera, acquiring the molten pool and molten runner images acquired at high speed by the high-speed camera may specifically include:

[0056] Acquire images of the molten pool morphology captured by the coaxial high-speed camera;

[0057] Acquire images of the melt flow path during the molding process captured by the rangefinder high-speed camera;

[0058] The process of using the high-speed processing module to process the molten pool image to obtain high-frequency molten pool feature information may specifically include:

[0059] The high-speed processing module uses image algorithms to determine high-frequency molten pool feature information based on the molten pool morphology image and the molten channel image. The high-frequency molten pool feature information includes at least molten pool width information and molten channel height information, thereby improving image acquisition efficiency and data processing efficiency.

[0060] in addition, Figure 1 The multivariable feedback controller integrates a PID database; the PID database contains historical printing data corresponding to different workpieces; the historical printing data includes at least process parameters, PID controller parameters, single correction amount, and printing morphology characteristics.

[0061] The multivariable feedback controller calculates the target controller parameters of the correction system based on the high-frequency molten pool characteristic information, specifically including:

[0062] The multivariable feedback controller calculates the optimal parameter range of the target controller based on the high-frequency molten pool and molten channel characteristic information and the PID database. It simultaneously controls multiple devices during the laser metal forming process, so that the target metal part is printed according to the desired process.

[0063] PID control, or Proportional(P)–Integral(I)–Derivative(D) Control, is actually a collective term for three types of feedback control: proportional control, integral control, and derivative control. Depending on the controlled object and application conditions, a combination of these three control methods can be used, namely P control, PI control, PD control, or a combination of all three, namely PID control. For P control, the deviation value e between the output and input is amplified or reduced proportionally as the system input to suppress the impact of disturbances on the system's steady state. However, because P control improves the system's response speed and steady-state accuracy, it inevitably leads to system overshoot and oscillation, resulting in steady-state error. I, or integral control, in contrast to P control, can eliminate steady-state error and has a certain degree of robustness. However, I control is prone to integral saturation and lacks the function of eliminating steady-state error for higher-order disturbances. D, or derivative control, is applied to dynamic systems. Its main function is to reduce overshoot, accelerate transient processes, and improve system stability. However, because D control amplifies high-frequency noise, selecting an appropriate D value is crucial.

[0064] The multivariable feedback controller can determine a suitable range of multivariable feedback controller parameters based on the actual needs of the printed workpiece, and quickly calculate the target controller parameters corresponding to each slave device.

[0065] To improve data transmission rates, this solution also employs EtherCAT bus technology. The multivariable feedback controller can send the target controller parameters to the industrial computer via the EtherCAT bus. Furthermore, to facilitate the use of the EtherCAT bus, the industrial computer should be connected to at least an EtherCAT coupler. The multivariable feedback controller transmits the target controller parameters to the industrial computer at high speed via the EtherCAT bus, and the industrial computer, through the EtherCAT coupler, triggers the slave device at the specified address to make a response adjustment.

[0066] The multivariables controlled by the multivariable feedback controller include at least laser power, laser cladding head feed speed, and powder feed rate; the multivariables are coupled with each other.

[0067] The multivariable feedback controller adjusts the width of the molten pool and the height of the molten channel during the laser metal forming process by regulating the parameters corresponding to the multivariables.

[0068] When the multivariable feedback control system performs correlation control of laser power and laser cladding head feed speed, it adjusts the real-time values ​​of laser power and laser cladding head feed speed by controlling the PID controller parameters of the laser power during the forming process, so as to adjust the characteristic values ​​of the molten pool width and the molten channel height.

[0069] The above method simplifies the control strategy of multivariate correlation regulation. The controllable variables, such as laser power P, laser cladding head feed speed U, and powder feeding amount F, have a certain coupling relationship with each other. They jointly control the morphological characteristics such as the molten pool width W and the molten channel height H in the laser metal forming process, thereby controlling the quality of the formed workpiece.

[0070] Taking the three variables—laser power P, feed speed U, and powder feed rate F—as an example, their corresponding state spaces are as follows: Figure 3 As shown, when the process parameters are located within the shaded area, the parameters are well matched, resulting in better forming quality of the printed parts. Since laser metal forming involves many parameters, the transfer function between the morphological characteristics of the formed workpiece and each parameter is described in formula (1):

[0071]

[0072] Where P is the laser power, U is the feed speed of the laser cladding head, W is the weld pool width, H is the weld channel height, q is the number of controlled process parameters, and n is the number of morphological feature types affecting the forming quality of metal parts. The weld pool width and weld channel height, among other characteristic values, have a certain conversion relationship with the equipment's control parameters. Therefore, G... 11 …G 1q This represents the influence of q process parameters on the first characteristic value—the weld pool width, G. n1 …G nq G represents the influence of these q process parameters on the nth characteristic value—the weld channel height. 11 …G nq Let K represent the transfer function between each process parameter and the morphological feature value during laser metal forming, respectively, and K be a variable.

[0073] In laser metal forming, the laser and metal powder converge on the upper surface of the substrate. A portion of the laser energy is absorbed by the metal powder and the substrate. Since the effect of thermal radiation is relatively small, it is negligible here. Taking the laser power and the feed rate of the laser cladding head as an example, assuming that it takes time dt to deposit metal powder with an infinitesimal distance dl, the feed rate of the laser cladding head can be approximated as not changing and is constant at U during this time. Thus, the matching relationship model between the two is established as shown in formula group (2):

[0074]

[0075] Where Eo is the laser output energy, Ee is the energy absorbed by the laser from the metal powder and substrate, which can be considered as the effective output energy of the laser, η is the energy utilization efficiency of the laser, P is the laser power, Q is the energy required to form a unit volume of workpiece, S is the cross-sectional area of ​​a single forming pass, Ea is the laser energy absorbed by the powder, and δ is the proportion of the energy absorbed by the powder to the effective output energy of the laser.

[0076] For the cross-section of a single-pass metal forming, a planar coordinate system can be established, and a cubic function can be selected to depict the contour curve function of the single pass. The curve function can be simplified according to the boundary conditions as shown in formula group (3):

[0077]

[0078] H is the height of the melt channel, and W is the width of the melt pool. Therefore, the cross-sectional area S of a single forming channel can be calculated using formula (4):

[0079]

[0080] The solution shows that the laser power and the feed rate are directly proportional within a certain range, as given by formula (5):

[0081]

[0082] After obtaining the PU relationship, multivariate control can be simplified as shown in formula (6):

[0083]

[0084] To verify the feasibility of this control strategy, a closed-loop control experiment was conducted using a suitable type of stainless steel powder as the forming raw material, focusing on the correlation between laser power and the feed rate of the laser cladding head. Through optimization using a multivariable-to-single-variable control strategy, the real-time values ​​of both laser power and feed rate could be simultaneously adjusted by controlling only the PID parameter of the laser power during the forming process. This effectively corrected the molten pool width and weld line height of the formed part. The regression equation established from the experimental data showed consistent coupling with the process parameters discussed above, demonstrating the successful application of this control strategy.

[0085] The solution provided by this invention addresses the forming control of a series of workpieces with complex curved surfaces, such as those with variable wall thickness and irregular spatial shapes. For these workpieces, if a conventional single-variable feedback control system is used, serious morphological defects such as collapse, edge heat accumulation, and obvious gaps between tracks will occur, making integrated forming impossible and resulting in low precision. The high-speed signal multivariable control system described in this invention acquires key information about the molten pool and melt channel morphology through coaxial and off-axis high-speed cameras, filters and processes this information, and then transmits it to a multivariable feedback controller. The controller internally simplifies the multivariable control strategy, considers the coupling relationship between different process parameters, and integrates a PID database. The system's built-in PID database can calculate a suitable range of controller parameters, allowing simultaneous control of multiple devices to adjust parameters during laser metal forming, achieving multi-dimensional real-time control of laser metal forming. Through a single data stream of EtherCAT bus technology, coupled with an EtherCAT coupler on the industrial control computer, the device at a specified address can be controlled and excited in a single operation within a very short delay. For the forming of complex workpieces, such as those with varying wall thicknesses or irregular spatial shapes, this scheme can promote a smooth transition between melt channels of different wall thicknesses, avoiding significant gaps that could damage the internal strength and other mechanical properties of the workpiece, thus achieving integrated forming. Simultaneously, this scheme provides guidance for achieving the desired forming effect. By using a PID database storing historical printing information of formed metal parts, the selected range of relevant controller parameters can be calculated, thus correcting the formed morphology. Furthermore, it provides experimental theoretical basis for exploring the influence of various process parameters on the forming quality of the workpiece, further improving the real-time control system, and enabling the production of more precise metal printed parts.

[0086] The EtherCAT bus technology employed transmits data between master and slave stations via messages, with a latency in the microsecond range. This significantly improves the synchronization of signals at the transmitting and receiving ends and the frequency of feedback control, suppressing the positive accumulation of deviation values. This ensures that the shape characteristics of the formed part remain within the desired range, improving forming accuracy. The invention integrates a simplified multivariate correlation control module, which can simulate the laser metal forming process before printing begins, determining the numerical range of multiple variables involved in the control based on forming requirements. Because this module has a built-in PID database storing historical printing information, subsequent machine learning algorithms can be used to predict the workpiece morphology generated under different process parameters, contributing to the realization of automated and intelligent integrated metal forming.

[0087] Furthermore, the solution of this invention can achieve high-speed signal acquisition up to 5KHz and feedback control frequency up to 1000Hz and above, ensuring superior tracking performance of molten pool changes, timely and sensitively capturing drastic changes in the molten pool, and guaranteeing the source of real-time control.

[0088] Based on the same approach, this specification also provides a high-speed signal multivariable control device. The high-speed signal multivariable control device is applied to... Figure 1 The high-speed signal multivariable control system in the text includes hardware components such as a high-speed camera, an industrial computer, a laser, a motion controller, a feeding device, and an atmosphere protection system, as well as software components including a high-speed processing module and a multivariable feedback controller. The equipment includes... Figure 4 As shown, it may include:

[0089] A communication unit / communication interface is used to acquire the molten pool image acquired at high speed by the high-speed camera;

[0090] A processing unit / processor is used to process the molten pool image using the high-speed processing module to obtain high-frequency molten pool feature information;

[0091] The high-frequency molten pool characteristic information is sent to the multivariable feedback controller, which calculates the target controller parameters of the correction system based on the high-frequency molten pool characteristic information.

[0092] The target controller parameters are sent to the industrial computer, and the industrial computer controls the corresponding slave device to work based on the target controller parameters.

[0093] like Figure 4 As shown, the terminal device described above may also include a communication line. The communication line may include a path for transmitting information between the components described above.

[0094] Optional, such as Figure 4 As shown, the terminal device may further include a memory. The memory stores computer execution instructions for implementing the present invention, and the execution is controlled by a processor. The processor executes the computer execution instructions stored in the memory, thereby implementing the method provided in the embodiments of the present invention.

[0095] In a specific implementation, as one example, such as Figure 4 As shown, a processor may include one or more CPUs and a GPU, such as Figure 4 The CPU consists of CPU0, CPU1, and GPU0. The CPU performs the core calculations and centralized control of the PID controller, while the GPU performs image processing and CUDA acceleration.

[0096] In a specific implementation, as one example, such as Figure 4 As shown, the terminal device may include multiple processors, such as Figure 4 The processors in the system. Each of these processors can be a single-core processor or a multi-core processor.

[0097] Based on the same idea, this specification also provides a computer storage medium corresponding to the above embodiments. The computer storage medium stores instructions that, when executed, implement the methods in the above embodiments.

[0098] The foregoing mainly describes the solutions provided by the embodiments of the present invention from the perspective of the interaction between various modules. It is understood that each module, in order to achieve the above functions, includes corresponding hardware structures and / or software units for executing each function. Those skilled in the art should readily recognize that, in conjunction with the units and algorithm steps of the various examples described in the embodiments disclosed herein, the present invention can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed by hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0099] The embodiments of the present invention can divide functional modules according to the above method examples. For example, each function can be divided into its own functional module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware or as a software functional module. It should be noted that the module division in the embodiments of the present invention is illustrative and only represents one logical functional division; other division methods may be used in actual implementation.

[0100] The memory can be read-only memory (ROM) or other types of static storage devices capable of storing static information and instructions, random access memory (RAM) or other types of dynamic storage devices capable of storing information and instructions, or electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, universal optical discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but not limited to these. The memory can exist independently, be connected to the processor via communication lines, or be integrated with the processor.

[0101] Optionally, the computer execution instructions in the embodiments of the present invention may also be referred to as application code, and the embodiments of the present invention do not specifically limit this.

[0102] The methods disclosed in the above embodiments of the present invention can be applied to a processor or implemented by a processor. The processor may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above methods can be completed by integrated logic circuits in the processor's hardware or by instructions in software form. The processor can be a general-purpose processor, a digital signal processor (DSP), an ASIC, a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of the present invention. A general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of the present invention can be directly embodied in the execution of a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules can be located in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located inside the memory; the processor reads the information in the memory and, in conjunction with its hardware, completes the steps of the above methods.

[0103] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present invention are performed entirely or partially. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a terminal, a user equipment, or other programmable device. The computer program or instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions can be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital video disc (DVD); or it can be a semiconductor medium, such as a solid-state drive (SSD).

[0104] Although the invention has been described herein in conjunction with various embodiments, those skilled in the art will understand and implement other variations of the disclosed embodiments by reviewing the accompanying drawings, the disclosure, and the appended claims in carrying out the claimed invention. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0105] Although the invention has been described in conjunction with specific features and embodiments, it is apparent that various modifications and combinations can be made therein without departing from the spirit and scope of the invention. Accordingly, this specification and drawings are merely exemplary descriptions of the invention as defined by the appended claims and are to be considered as covering any and all modifications, variations, combinations, or equivalents within the scope of the invention. Those skilled in the art can make various alterations and modifications to the invention without departing from its spirit and scope.

Claims

1. A high-speed signal multivariable control method, characterized in that, The high-speed signal multivariable control method is applied to a high-speed signal multivariable control system. The hardware of the high-speed signal multivariable control system includes: a high-speed camera, an industrial computer, slave devices, and an EtherCAT bus. The industrial computer is connected to an EtherCAT coupler, which establishes connections between each slave device and the EtherCAT bus. The EtherCAT coupler converts EtherCAT bus information into I / O signals to control each slave device. The software of the high-speed signal multivariable control system includes: a high-speed processing module and a multivariable feedback controller. The high-speed signal multivariable control method includes: Acquire the molten pool image captured at high speed by the high-speed camera; The high-speed processing module is used to process the molten pool image to obtain high-frequency molten pool feature information; The high-frequency molten pool characteristic information is sent to the multivariable feedback controller, which calculates the target controller parameters of the correction system based on the high-frequency molten pool characteristic information. The multivariable feedback controller sends the target controller parameters to the industrial computer via the EtherCAT bus, and the industrial computer controls the corresponding slave device to work based on the target controller parameters; the industrial computer triggers the slave device at a specified address to make a response adjustment through the EtherCAT coupler; The multivariable feedback controller integrates a PID database; the PID database contains historical printing data corresponding to different workpieces, and the historical printing data includes at least process parameters, PID controller parameters, single correction amount, and printing morphology features; The multivariable feedback controller calculates the target controller parameters of the correction system based on the high-frequency molten pool characteristic information, specifically including: The multivariable feedback controller calculates the optimal range of the target controller parameters based on the high-frequency molten pool and molten channel characteristic information and the PID database. During the laser metal forming process, it simultaneously controls multiple slave devices to ensure that the target metal part is printed according to the desired process. The high-speed processing module is used to process the molten pool image to obtain high-frequency molten pool feature information, specifically including: The high-speed processing module uses image algorithms to determine high-frequency molten pool feature information based on the molten pool morphology image and the molten track image; the high-frequency molten pool feature information includes at least molten pool width information and molten track height information. The multivariable feedback controller controls at least the laser power, the laser cladding head feed speed, and the powder feeding amount; the multivariables are coupled with each other. The multivariable feedback controller obtains the molten pool width information and the molten channel height information that continuously approach the desired value during the laser metal forming process by adjusting the controller parameters corresponding to the multivariables.

2. The high-speed signal multivariable control method according to claim 1, characterized in that, The slave device includes at least a laser, a motion controller, a feeding device, and an atmosphere protection system.

3. The high-speed signal multivariable control method according to claim 1, characterized in that, The high-speed camera includes a coaxial high-speed camera and a rangefinder high-speed camera; The acquisition of the molten pool image captured at high speed by the high-speed camera specifically includes: Acquire images of the molten pool morphology captured by the coaxial high-speed camera; The melting channel image during the molding process is acquired by the off-axis high-speed camera.

4. The high-speed signal multivariable control method according to claim 1, characterized in that, High-speed signal multivariable control systems also include: EtherCAT master and slave stations; The slave device includes at least a laser, a motion controller, a feeding device, and an atmosphere protection system; The master station is an industrial control computer, which controls the slave devices by regulating the parameter transmission of the slave stations; the slave stations are EtherCAT couplers. The slave station includes an EtherCAT communication interface and I / O terminals. The EtherCAT communication interface is connected to the slave station through a physical layer chip and a network transformer to realize EtherCAT communication between the master station and the slave station. Control signals are directly connected to the slave device through the I / O terminals.

5. The high-speed signal multivariable control method according to claim 4, characterized in that, When the system performs correlated control of laser power and laser cladding head feed speed, it can simultaneously adjust the real-time values ​​of laser power and laser cladding head feed speed by controlling the PID parameters of the laser power during the forming process, so as to correct the melt pool width information and the melt channel height information.

6. A high-speed signal multivariable control device, characterized in that, The high-speed signal multivariable control device is applied to a high-speed signal multivariable control system. The hardware of the high-speed signal multivariable control system includes: a high-speed camera, an industrial computer, slave devices, and an EtherCAT bus. The industrial computer is connected to an EtherCAT coupler, which establishes connections between each slave device and the EtherCAT bus. The EtherCAT coupler converts EtherCAT bus information into I / O signals to control each slave device. The software of the high-speed signal multivariable control system includes: a high-speed processing module and a multivariable feedback controller. The high-speed signal multivariable control device includes: A communication unit / communication interface is used to acquire the molten pool image acquired at high speed by the high-speed camera; A processing unit / processor is used to filter and process the molten pool image using the high-speed processing module to obtain high-frequency molten pool feature information; The multivariable feedback controller sends the high-frequency molten pool characteristic information to the multivariable feedback controller via the EtherCAT bus, and the multivariable feedback controller calculates the target controller parameters of the correction system based on the high-frequency molten pool characteristic information. The target controller parameters are sent to the industrial control computer, which controls the corresponding slave device to work based on the target controller parameters; the industrial control computer triggers the slave device at the specified address to make a response adjustment through the EtherCAT coupler; The multivariable feedback controller integrates a PID database; the PID database contains historical printing data corresponding to different workpieces, and the historical printing data includes at least process parameters, PID controller parameters, single correction amount, and printing morphology features; The multivariable feedback controller calculates the target controller parameters of the correction system based on the high-frequency molten pool characteristic information, specifically including: The multivariable feedback controller calculates the optimal range of the target controller parameters based on the high-frequency molten pool and molten channel characteristic information and the PID database. During the laser metal forming process, it simultaneously controls multiple slave devices to ensure that the target metal part is printed according to the desired process. The high-speed processing module is used to process the molten pool image to obtain high-frequency molten pool feature information, specifically including: The high-speed processing module uses image algorithms to determine high-frequency molten pool feature information based on the molten pool morphology image and the molten track image; the high-frequency molten pool feature information includes at least molten pool width information and molten track height information. The multivariable feedback controller controls at least the laser power, the laser cladding head feed speed, and the powder feeding amount; the multivariables are coupled with each other. The multivariable feedback controller obtains the molten pool width information and the molten channel height information that continuously approach the desired value during the laser metal forming process by adjusting the controller parameters corresponding to the multivariables.

7. A computer storage medium, characterized in that, The computer storage medium stores instructions that, when executed, implement the high-speed signal multivariable control method according to any one of claims 1 to 5.

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