An intelligent arc striking system based on laser-assisted preheating

Abstract

The present application relates to the field of material processing technology, and more particularly to an intelligent arc striking system based on laser-assisted preheating, comprising: a data acquisition module for acquiring data of a weld seam of an arc striking plate during laser heating and data of a piece to be welded; a correlation analysis module for obtaining a data correlation index of the arc striking plate according to the distribution of arc data and temperature data of the weld seam of the arc striking plate; an accuracy analysis module for obtaining an accuracy index of the preheating temperature of the piece to be welded according to the distribution difference between the temperature data and the laser power data of the weld seam of the arc striking plate, in combination with actual temperature data and actual laser power data of the piece to be welded; an arc striking control module for controlling actual temperature data of the piece to be welded according to the data correlation index and the accuracy index, in combination with actual temperature data and actual arc data, and performing arc striking operation on the piece to be welded based on the temperature control result. The present application improves the arc striking success rate and reduces arc striking defects.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of material processing technology, in particular to an intelligent arc striking system based on laser-assisted preheating. BACKGROUND

[0002] Arc striking is the process of establishing and igniting an electric arc in the welding process. Through the current between the electrode and the workpiece, the gas or metal vapor between them is broken down, forming a stable burning electric arc, which provides a high-temperature heat source for welding. On the cold metal surface, the low conductivity and the presence of an oxide film or contamination layer result in a high arc breakdown voltage. Traditional arc striking methods face difficulties in arc striking, high risk of defects, increased energy consumption, and reduced welding efficiency. Recently, by using laser to locally heat the welding area before arc striking, real-time monitoring of temperature and arc characteristics, combined with intelligent control algorithms to achieve automatic arc striking, can help improve arc striking stability, reduce energy consumption, and reduce welding defects, and has important engineering application value and industrial prospects.

[0003] In the prior art, in the process of intelligent arc striking with laser-assisted preheating, the temperature at the center of the laser spot is usually monitored in real time as a feedback signal to adjust the preheating power and determine the arc striking time, thereby achieving precise arc striking control. However, infrared temperature sensors are extremely susceptible to strong laser reflections and subsequent arc light interference. The high reflectivity of the laser itself produces strong reflected light on the workpiece surface, which directly enters the temperature measurement optical path, making the sensor unable to obtain the true workpiece temperature during laser action. At the critical moment before arc striking, the accuracy and real-time nature of the temperature data directly determine the arc striking control, but the signals collected by the sensor at this time are often distorted or lagging, causing the control algorithm to make decisions based on incorrect core inputs, resulting in incorrect arc striking timing and even arc striking failure. SUMMARY

[0004] To solve the technical problem of temperature data distortion in the process of intelligent arc striking with laser-assisted preheating in the prior art, which leads to low arc striking success rate, the purpose of the present application is to provide an intelligent arc striking system based on laser-assisted preheating, the technical solution adopted is as follows:

[0005] An intelligent arc striking system based on laser-assisted preheating, comprising:

[0006] A data acquisition module for acquiring temperature data, arc data, and laser power data of the weld at each time during the laser heating process of the arc striking plate, as well as actual temperature data, actual arc data, and actual laser power data of the workpiece to be welded during laser preheating;

[0007] The correlation analysis module is configured to analyze the relationship between the arc characteristics and the temperature change according to the distribution of the arc data and the distribution of the temperature data of the arc striking plate weld, and obtain a data correlation index of the arc striking plate.

[0008] The accuracy analysis module is configured to obtain an accuracy index of the preheating temperature of the workpiece to be welded according to the difference between the distribution of the temperature data and the laser power data of the arc striking plate weld, and the distribution between the actual temperature data and the actual laser power data of the workpiece to be welded.

[0009] The arc striking control module is configured to control the actual temperature data of the workpiece to be welded according to the data correlation index and the accuracy index, and the relationship between the actual temperature data and the actual arc data, and perform an arc striking operation on the workpiece to be welded based on the temperature control result.

[0010] Preferably, the correlation analysis module comprises:

[0011] The feature analysis unit is configured to obtain an arc characteristic value of the arc striking plate weld according to the difference between the arc data of adjacent time sequences of the arc striking plate weld and the range distribution of the arc data.

[0012] The correlation determination unit is configured to obtain a data correlation index of the arc striking plate according to the correlation between the temperature data and the arc characteristic value of the arc striking plate weld.

[0013] Preferably, the arc striking plate comprises at least two welds.

[0014] The feature analysis unit is configured to:

[0015] determine a first difference coefficient based on the balance of the difference between the arc data of each weld of the arc striking plate at adjacent two time points, and determine a second difference coefficient as the range of the arc data of each weld of the arc striking plate at all time points;

[0016] determine a third difference coefficient as the difference between the maximum value of the arc data of each weld of the arc striking plate and the average value of all arc data of the weld;

[0017] perform negative correlation processing on the product of the first difference coefficient, the second difference coefficient, and the third difference coefficient to obtain an arc characteristic value of each weld of the arc striking plate.

[0018] Preferably, the correlation determination unit is configured to:

[0019] determine the data correlation index of the arc striking plate based on the ratio relationship between the difference between the temperature data of each adjacent two welds at the initial time and the difference between the arc characteristic values.

[0020] Preferably, the accuracy analysis module comprises:

[0021] a relationship determining unit, configured to obtain a corresponding dynamic change relationship between the temperature and the laser at each weld of the arc striking plate according to a difference distribution between the temperature data and the laser power data of each weld of the arc striking plate;

[0022] an accuracy determining unit, configured to obtain an accuracy index of the preheating temperature of the workpiece according to a difference between the corresponding dynamic change relationship of the workpiece and the corresponding dynamic change relationship of each weld of the arc striking plate.

[0023] Preferably, the relationship determining unit is configured to:

[0024] construct a standard temperature sequence of each weld of the arc striking plate based on a standardization processing result of the temperature data of each weld of the arc striking plate, and construct a standard laser sequence of each weld of the arc striking plate based on a standardization processing result of the laser power data of each weld of the arc striking plate;

[0025] perform a negative correlation processing on a difference distance between the standard temperature sequence and the standard laser sequence of each weld to obtain the corresponding dynamic change relationship between the temperature and the laser of each weld.

[0026] Preferably, the accuracy determining unit is configured to:

[0027] determine the negative correlation processing result of a difference between the corresponding dynamic change relationship of the workpiece and a mean value of the corresponding dynamic change relationship of all welds of the arc striking plate as the accuracy index of the preheating temperature of the workpiece.

[0028] Preferably, the arc striking control module comprises:

[0029] a control analysis unit, configured to obtain a current arc characteristic value of the workpiece, and obtain a temperature control amplitude of the workpiece according to the data correlation index of the arc striking plate, the current arc characteristic value of the workpiece, actual temperature data at a current time, and a correlation between the temperature data and the arc characteristic value of each weld of the arc striking plate.

[0030] an error analysis unit, configured to determine a product between a negative correlation coefficient of the accuracy index and the actual temperature data at the current time of the workpiece as a temperature error value of the workpiece.

[0031] a temperature value determining unit, configured to obtain a temperature input value of laser-assisted preheating of the workpiece according to the temperature control amplitude and the temperature error value, and the actual temperature data of the workpiece.

[0032] Preferably, the control analysis unit is configured to:

[0033] An absolute value of a Pearson correlation coefficient between the arc characteristic value and the temperature data of each weld of the arc striking plate is taken as a correlation coefficient;

[0034] Based on the distribution of the actual arc data and the analysis of the actual temperature data of the to-be-welded piece, the current arc characteristic value of the to-be-welded piece is determined.

[0035] A difference between a product between the data correlation index of the arc striking plate and the current arc characteristic value and the actual temperature data at the current moment is determined as a temperature difference coefficient.

[0036] A product between the temperature difference coefficient and the correlation coefficient is taken as a temperature regulation amplitude of the to-be-welded piece.

[0037] Preferably, the temperature value determination unit is configured to:

[0038] A product between the temperature regulation amplitude and the temperature error value and an accumulation between the actual temperature data of the to-be-welded piece at the current moment are taken as a temperature input value of the laser-assisted preheating of the to-be-welded piece.

[0039] The embodiments of the present application have at least the following beneficial effects:

[0040] The present application firstly uses the data acquisition module to collect the temperature, arc and laser power data of the weld of the arc striking plate in the laser-assisted preheating stage as the basis of the historical statistical data model construction, and collects the temperature, arc and laser power data of the to-be-welded piece in the current preheating stage as the basis of the current preheating stage to be regulated. Then, the correlation analysis module is used to analyze the action relationship between the arc characteristics and the temperature change through the distribution of the arc data and the distribution of the temperature data of the weld of the arc striking plate, to obtain the data correlation coefficient representing the correlation rule between the temperature and the arc characteristics, and to use the arc characteristics as a supplementary signal to make up for the deficiency when the temperature feedback is disturbed. Further, the accuracy analysis module is used to compare the historical difference distribution of the weld of the arc striking plate and the actual difference distribution of the to-be-welded piece to evaluate the accuracy degree of the current laser-assisted preheating temperature of the to-be-welded piece. Finally, the arc regulation module is used to adjust the actual temperature by comprehensively considering the data correlation index and the accuracy index. When the accuracy of the temperature signal decreases, the actual arc characteristics of the current to-be-welded piece are introduced as auxiliary signals to construct a joint feedback, to realize the dynamic correction of the arc striking stage control strategy, to improve the fault tolerance and the intelligent level of the arc striking control system, to improve the arc striking success rate, to reduce the arc striking defects, to ensure the welding quality and the process stability. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, and the advantages thereof, below will briefly introduce the drawings needed in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0042] Figure 1 is a structural schematic diagram of an intelligent arc striking system based on laser auxiliary preheating provided by the present application;

[0043] Figure 2 is a schematic diagram of an arc striking plate and a piece to be welded provided by the present application;

[0044] Figure 3 is a structural schematic diagram of a relevance analysis module provided by the present application;

[0045] Figure 4 is a structural schematic diagram of an accuracy analysis module provided by the present application;

[0046] Figure 5 is a structural schematic diagram of an arc striking regulation module provided by the present application. DETAILED DESCRIPTION

[0047] In order to further illustrate the technical means and effects taken by the present application to achieve the predetermined invention purpose, below, combined with the drawings and preferred embodiments, the specific implementation, structure, features and effects of the intelligent arc striking system based on laser auxiliary preheating provided by the present application are described in detail as follows. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.

[0049] Below, the specific scheme of the intelligent arc striking system based on laser auxiliary preheating provided by the present application is specifically described in combination with the drawings.

[0050] The specific implementation scene to which the embodiment of the present application is directed is that in the process of realizing arc striking control by monitoring the center temperature of a laser spot as a feedback signal, the infrared sensor is easily disturbed by strong laser reflection and subsequent arc light, resulting in distorted or even lagged temperature data at the key moment before arc striking, thereby increasing the risk of arc striking failure. Therefore, the present application realizes dynamic feedback control of the arc striking process by implementing laser preheating on the arc striking plate and combining analysis of the relationship between the laser temperature of the weld area and the arc characteristics, thereby effectively improving the arc striking success rate, reducing weld defects caused by arc striking failure, improving the welding quality of the arc striking section and the stability of the overall welding process, and providing reliable technical support for efficient and intelligent arc striking in thick plate welding.

[0051] Referring to Figure 1 , a structure diagram of an intelligent arc striking system based on laser-assisted preheating is shown, the intelligent arc striking system based on laser-assisted preheating 100 comprises a data acquisition module 110, a correlation analysis module 120, an accuracy analysis module 130 and an arc striking regulation module 140.

[0052] The data acquisition module 110 is used to acquire the temperature data, arc data and laser power data of the weld of the arc striking plate at each moment during laser heating, and to acquire the actual temperature data, actual arc data and actual laser power data of the workpiece to be welded during laser preheating.

[0053] In the embodiment, the arc striking plate contains at least two welds, and specifically adopts an arc striking plate formed by splicing multiple steel plates consistent with the thickness and material of the workpiece to be welded, as shown in Figure 2 , where 2 represents the arc striking plate and 1 represents the workpiece to be welded, and the arc striking plate is formed by splicing five identical steel plates and contains four welds. Further, by analyzing the data distribution of the temperature, arc and laser on the arc striking plate, a pre-modeling operation of the arc striking plate data is performed to dynamically feedback and regulate the actual welding temperature of the workpiece to be welded in combination with the data distribution of the actual preheating process of the workpiece to be welded.

[0054] Based on this, the embodiment collects the temperature data, arc data and laser power data of each weld of the arc striking plate at each moment during the laser preheating time period, and simultaneously collects the actual temperature data, actual arc data and actual laser power data of the workpiece to be welded at each moment during the current laser preheating time period.

[0055] More specifically, the infrared temperature sensor is installed above the weld at an inclined angle (which can be 40°, and the implementer can set it according to the specific implementation scenario), is aligned with the center of the laser spot, collects the temperature of the center of the laser spot of each weld of the arc striking plate as the temperature data corresponding to each weld, and collects the temperature of the center of the laser spot at the welding position of the workpiece to be welded as the actual temperature data of the workpiece to be welded.

[0056] In the embodiment, the arc data can be current data or voltage data. A current sensor (Hall sensor) is installed between the welding power source and the wire feeding system; a voltage sensor is connected to the lead wire between the welding torch conducting nozzle and the workpiece, and the sampling point is close to the arc area. Both are connected to the data acquisition card (DAQ card) through anti-interference shielded wires. The implementer can select according to the specific implementation scenario, and the embodiment takes the current data as an example for feature analysis. Further, the laser has a power monitoring interface inside, which can directly record the laser power data at the corresponding time.

[0057] It should be noted that the specific position of the sensor needs to be set by the implementer according to the specific implementation scenario.

[0058] Finally, the data acquisition time is synchronized to ensure that the temperature data, arc data and laser power data are time-aligned, and denoising and smoothing are performed.

[0059] The correlation analysis module 120 is configured to analyze the action relationship between the arc characteristics and the temperature change according to the distribution of the arc data and the distribution of the temperature data of the weld of the arc striking plate, and obtain a data correlation index of the arc striking plate.

[0060] The laser preheating improves the initial temperature of the weld area, reduces the obstruction of the metal surface oxide film and impurities to the arc breakdown, and makes the arc easier to establish. The change law of the arc voltage and current at the moment of striking the arc can directly reflect whether the arc striking is smooth and the stability of the arc. If the laser preheating temperature is insufficient, the voltage overshoot, current fluctuation or even arc extinction phenomenon may occur in the arc establishment process. Only relying on temperature feedback has uncertainty (affected by reflected laser and arc light), while the arc characteristics are a direct manifestation of the quality of arc striking. By analyzing the corresponding relationship between the laser spot temperature and the arc characteristics, the closed-loop control accuracy can be improved.

[0061] In this regard, as shown in Figure 3 The correlation analysis module 120 further includes the following units: a feature analysis unit 121 and a correlation determination unit 122.

[0062] The feature analysis unit 121 is configured to obtain an arc characteristic value of the weld of the arc striking plate according to the difference of the arc data of the adjacent time sequences of the weld of the arc striking plate and the range distribution of the arc data.

[0063] In the intelligent arc striking process, the arc data before the transition to the next block of spliced steel plate can reflect the effect of laser-assisted preheating, and the arc characteristics in the striking stage are a direct manifestation of whether the preheating condition can meet the arc breakdown requirement. Because the laser preheating provides sufficient free electrons and ions, the air is highly ionized, and the arc is easily and reliably established without high frequency and high voltage. When the arc data has a small jump amplitude and the arc data in the preparation stage before the arc striking is relatively stable, the arc characteristics of the weld arc striking are good. According to the arc data before the weld and the arc stability, by analyzing the fluctuation of the arc data before the arc striking, when the arc data is stably fluctuated in a small range, it indicates that the arc stability is high, and the possibility of successful establishment of the arc is high. The arc characteristics corresponding to each weld arc striking on the arc striking plate are evaluated.

[0064] Specifically, in the first step, a first difference coefficient is determined based on the balance of the difference between the arc data of each weld on the arc striking plate at two adjacent time points.

[0065] In this embodiment, an arbitrary weld on the arc striking plate is taken as an example for illustration, for example, the i-th weld on the arc striking plate is taken as an example, the mean value of the difference between the arc data of the i-th weld at two adjacent time points is calculated , and the first difference coefficient corresponding to the i-th weld is determined. Wherein, represents the arc data of the i-th weld on the arc striking plate at the m-th time point, represents the arc data of the i-th weld on the arc striking plate at the m+1-th time point, represents the time length of the laser-assisted preheating stage of the i-th weld.

[0066] The first difference coefficient reflects the time sequence fluctuation degree of the arc data of the weld on the arc striking plate, and the mean value is used to represent the balance of the difference between the arc data of each two adjacent time points, and comprehensively reflects the time sequence fluctuation of the arc data of the weld on the arc striking plate in the preheating stage.

[0067] In the second step, the range of the arc data of each weld on the arc striking plate at all time points is determined as a second difference coefficient.

[0068] It should be noted that the range is the difference between the maximum value and the minimum value of the arc data of each weld at all time points, and this acquisition method is a known technology, which will not be described here.

[0069] The second difference coefficient reflects the data fluctuation range of the weld on the arc striking plate, and the smaller the value is, the smaller the arc data fluctuation range of the weld on the arc striking plate is, and the higher the data stability degree is.

[0070] In the third step, the difference between the maximum value of the arc data of each weld on the arc striking plate and the mean value of all arc data of the weld is determined as a third difference coefficient.

[0071] Specifically, taking the i-th weld on the arc striking plate as an example, the mean value of all the arc data of the i-th weld reflects the balanced distribution of the arc data of the weld in the preheating stage, and the absolute value of the difference between the maximum value and the mean value of all the arc data of the i-th weld on the arc striking plate is taken as the third difference coefficient corresponding to the i-th weld.

[0072] The third difference coefficient reflects the relative distribution of the peak arc data of the i-th weld. The greater the value, the greater the possibility of abnormal peak value of the arc data of the i-th weld in the preheating stage.

[0073] In the fourth step, the product of the first difference coefficient, the second difference coefficient and the third difference coefficient is processed in a negative correlation to obtain the arc characteristic value of each weld on the arc striking plate.

[0074] The first difference coefficient reflects the fluctuation of the arc data of the weld from the time sequence change of the data, the second difference coefficient reflects the fluctuation of the arc data of the weld from the distribution range of the data, and the third difference coefficient reflects the fluctuation of the arc data of the weld from the peak relative distribution of the data. Then, the analysis results of the three aspects are integrated in the form of product, and the logical relationship is corrected through negative correlation processing to obtain the arc characteristic value of each weld on the arc striking plate. In this embodiment, the negative correlation processing result is taken as the arc characteristic value of the weld on the arc striking plate, represents an exponential function with the natural constant e as the base, represents the product of the first difference coefficient, the second difference coefficient and the third difference coefficient corresponding to any one weld on the arc striking plate.

[0075] The smaller the first difference coefficient corresponding to each weld on the arc striking plate, the more stable the distribution of the arc data of the weld in the preheating stage. The smaller the second difference coefficient, the smaller the fluctuation range of the data of the weld in the preheating stage. The smaller the third difference coefficient, the greater the possibility of normal relative distribution of the data peak of the weld in the preheating stage. Then, the greater the value of the arc characteristic value, the more stable and normal the state of the arc of the weld through the three-dimensional cooperative evaluation, that is, the arc characteristic value represents the arc stability characteristic performance of the weld, and further reflects the possibility of successful arc striking of the weld. Based on this, the arc characteristic value of each weld on the arc striking plate represents the arc characteristics corresponding to the laser preheating process of each weld on the arc striking plate.

[0076] The correlation determination unit 122 is configured to obtain a data correlation index of the arc striking plate according to the correlation between the temperature data and the arc characteristic value of the weld on the arc striking plate.

[0077] The laser preheating temperature determines the metal surface state and local conductivity, and the arc characteristic value reflects the arc characteristics, which is a direct embodiment of the success of arc striking and its stability. By analyzing the temperature change of the weld of the arc striking plate and the change of the arc characteristics, based on the collected multi-weld data, the relationship between temperature and arc characteristics is measured, the correlation strength of temperature change and arc characteristic change is reflected, and a mathematical model is constructed between the temperature data of the arc striking plate before arc striking and the arc characteristic value.

[0078] Specifically, based on the ratio relationship between the difference between the temperature data of each adjacent two welds at the initial time and the difference between the arc characteristic values, the data correlation index of the arc striking plate is determined.

[0079] As a specific example, the data correlation index of the arc striking plate can be expressed by the formula:

[0080]

[0081] Among them, indicates the data correlation index of the arc striking plate, indicates the temperature data of the i th weld of the arc striking plate at the initial time, indicates the temperature data of the i+1 th weld of the arc striking plate at the initial time, indicates the arc characteristic value of the i th weld of the arc striking plate, indicates the arc characteristic value of the i+1 th weld of the arc striking plate, indicates the number of welds contained on the arc striking plate.

[0082] The temperature data at the initial time indicates the laser spot temperature at the laser preheating arc striking moment of the weld, reflects the temperature change between adjacent welds, reflects the change of the arc characteristics between adjacent welds. Through the ratio relationship between the temperature difference and the arc characteristic difference , the temperature change corresponding to the unit change of the arc characteristic is characterized.

[0083] At this point, the data correlation index of the arc striking plate characterizes the correlation degree between the temperature change and the arc characteristic change of the weld on the arc striking plate, and further reflects the sensitivity degree of the temperature to the arc characteristics.

[0084] It should be noted that the dynamic change relationship between temperature and arc characteristics is more critical than the static absolute ratio during the arc striking process. For example, under the same arc characteristics, the laser spot temperature at different preheating stages may be different, but how much does the temperature change correspond to the change of 1 unit of the arc characteristic to reflect the correlation rule of the two, and further provide a reliable benchmark for subsequent dynamic correction.

[0085] The accuracy analysis module 130 is configured to obtain an accuracy index of the preheating temperature of the workpiece to be welded according to the difference between the distribution of the temperature data and the laser power data of the arc striking plate weld and the distribution between the actual temperature data and the actual laser power data of the workpiece to be welded.

[0086] In the process of welding the workpiece, the arc is the main heat source during welding, and the arc melts the welding wire and the workpiece to increase the surface temperature of the workpiece and reduce the absorption of the cold metal workpiece to the arc, so that the arc is more easily and stably established. The medium between the electrode and the workpiece needs to be broken down and a stable arc needs to be established through intelligent arc striking, and local heating of the welding area is realized by using a laser before arc striking. Real-time monitoring of the laser spot temperature is the core of realizing intelligent arc striking closed-loop control, but in the actual process, infrared temperature measurement is easily disturbed by strong reflected laser, resulting in temperature signal deviation or even failure. In order to ensure the control accuracy, when analyzing the temperature measurement data of the spliced weld of the arc striking plate, the accuracy of the temperature data needs to be evaluated to ensure the reliability of the subsequent feedback control.

[0087] To this end, as shown in Figure 4 The accuracy analysis module 130 further includes the following units: a relationship determining unit 131 and an accuracy determining unit 132.

[0088] The relationship determining unit 131 is configured to obtain a corresponding dynamic change relationship between the temperature and the laser at each weld of the arc striking plate according to the difference distribution between the temperature data and the laser power data of each weld of the arc striking plate.

[0089] For the weld inside the arc striking plate during the laser preheating process, since the monitoring value of the laser spot temperature is easily disturbed by the laser, the change trend of the laser power and the spot temperature is taken as a reference to evaluate the accuracy of the laser spot temperature. According to the laser power and the spot temperature at each weld during the laser preheating process, the dynamic change relationship between the laser power data and the temperature data at the weld of the arc striking plate is evaluated.

[0090] Specifically, in the first step, based on the standardized processing result of the temperature data of each weld of the arc striking plate, a standard temperature sequence of each weld of the arc striking plate is constructed, and based on the standardized processing result of the laser power data of each weld of the arc striking plate, a standard laser sequence of each weld of the arc striking plate is constructed.

[0091] Firstly, considering that the preheating stage before the arc striking only directly affects the arc striking decision when the temperature is close to the arc striking temperature, the power and temperature are associated, for example, if the temperature data of the preheating stage before the arc striking is far lower than the arc striking temperature, even if the current temperature measurement result has a certain error, the system can also judge that the current preheating temperature does not meet the arc striking condition, at this time, the temperature measurement error does not affect the subsequent arc striking decision. If the temperature data of the preheating stage before the arc striking is close to the arc striking temperature, and the temperature measurement result at this time has an error, it may lead to misjudgment and may miss the arc striking opportunity. Therefore, by screening the temperature data of the weld preheating stage, the calculation amount can be reduced to a certain extent.

[0092] More preferably, the part close to the arc striking temperature is screened from the temperature data of the weld of the arc striking plate, and the laser power data at the corresponding moment is synchronously acquired, and finally through the dynamic correlation, the dynamic change relationship between the two can be accurately evaluated.

[0093] Specifically, a preset target temperature range is acquired, the temperature data of each weld on the arc striking plate located in the target temperature range is acquired, and the temperature data sequence corresponding to each weld is formed in time sequence; the laser power data of the weld at the corresponding moment in the temperature data sequence of each weld is formed into a laser power sequence.

[0094] In the embodiment, the target temperature range represents the data neighborhood range of the laser spot temperature required to reach the arc striking decision, and the arc striking condition temperature refers to the laser spot temperature required to reach the arc striking condition. In the embodiment, the arc striking condition temperature ± 10℃ is determined as the target temperature range, for example, the arc striking condition temperature is 200℃, and the target temperature range is [190, 210]. It should be noted that the embodiment is only illustrative, and the arc striking condition temperature needs to be set by relevant staff according to different specific implementation scenarios, which is not limited herein.

[0095] Further, in order to avoid the influence of different dimensions on the analysis result of data difference, the standardization processing is respectively performed on each temperature data in the temperature data sequence corresponding to each weld to obtain a standard temperature sequence, and the standardization processing is respectively performed on each laser power data in the laser power sequence corresponding to each weld to obtain a standard laser sequence. The standardization manner can adopt the Z-score standardization manner for processing, and the standardization method is a known technology, which is not limited herein.

[0096] Secondly, the difference distance between the standard temperature sequence and the standard laser sequence of each weld is negatively correlated to obtain the corresponding dynamic change relationship between the temperature and the laser of each weld.

[0097] As a specific example, the i th weld of the arc striking plate is taken as an example for description, and the dynamic change relationship between the temperature and the laser of the i th weld of the arc striking plate is may be expressed as: wherein, DTWi represents the DTW distance between the standard temperature sequence and the standard laser sequence of the i th weld, exp represents the exponential function with the natural constant e as the base.

[0098] DTWi represents the difference matching distance between the corresponding change data of the laser power and the laser spot temperature of the i th weld of the arc striking plate, represents the corresponding change relationship between the laser power and the temperature, and the smaller the DTW distance between the two, the more similar the changes between the laser power and the temperature. The corresponding dynamic change relationship between the temperature and the laser of each weld represents the degree of similarity of the dynamic changes between the temperature data and the laser power data of the weld.

[0099] The accuracy determination unit 132 is configured to obtain an accuracy index of the preheating temperature of the workpiece to be welded according to the difference between the corresponding dynamic change relationship of the workpiece to be welded and the corresponding dynamic change relationship of each weld of the arc striking plate.

[0100] The welds inside the arc striking plate composed of steel plates have the same material thickness as the welds of the workpiece to be welded. When the dynamic change relationship between the laser power and the laser spot temperature at the splicing weld of the workpiece to be welded is similar to the dynamic change relationship between the laser power and the laser spot temperature of all the welds of the arc striking plate, the measurement result of the laser spot temperature of the workpiece to be welded is more accurate. Based on this, the accuracy of the measurement result of the laser spot temperature of the workpiece to be welded is evaluated according to the corresponding dynamic change relationship between the temperature and the laser of all the welds of the arc striking plate and the corresponding dynamic change relationship between the temperature and the laser at the splicing weld of the workpiece to be welded.

[0101] Specifically, the negative correlation processing result of the difference between the corresponding dynamic change relationship of the workpiece to be welded and the average of the corresponding dynamic change relationship of all the welds of the arc striking plate is determined as the accuracy index of the preheating temperature of the workpiece to be welded.

[0102] It should be noted that the corresponding dynamic change relationship between the temperature and the laser of the workpiece to be welded is calculated according to the method of obtaining the dynamic change relationship of the weld of the arc striking plate in the relationship determination unit 131 based on the actual temperature data and the actual laser power data of the workpiece to be welded, and will not be described in detail here.

[0103] As a specific example, the accuracy index of the preheating temperature of the workpiece to be welded can be expressed as , DTW represents the corresponding dynamic change relationship between the temperature and the laser of the workpiece to be welded, DTW represents the average of the corresponding dynamic change relationship between the temperature and the laser of all the welds of the arc striking plate, exp represents the exponential function with the natural constant e as the base.

[0104] The dynamic change relationship corresponding to the workpiece to be welded reflects the similarity between the change of the temperature data and the change of the laser power data of the workpiece to be welded in the current preheating process. The mean of the dynamic change relationships corresponding to all the welds of the arc striking plate reflects the balance of the similarity between the change of the temperature data and the change of the laser power data in the statistical results of the historical welding data. The smaller the difference between the two is, the greater the data accuracy of the current preheating process of the workpiece to be welded is.

[0105] The arc striking control module 140 is configured to control the actual temperature data of the workpiece to be welded according to the data correlation index and the accuracy index, and perform an arc striking operation on the workpiece to be welded based on the temperature control result.

[0106] In the laser-assisted preheating process, temperature measurement is easily disturbed by reflected laser and subsequent arc light, resulting in inaccurate or even lost temperature feedback. If the control algorithm relies on false signals, it will cause arc striking failure or welding quality decline. The arc striking stage is extremely short, and the arc establishment process is highly nonlinear. If the feedback control cannot respond to changes in real time, the best arc striking opportunity will be missed. Using only temperature as feedback cannot completely describe the arc striking quality, while arc characteristics can reflect whether the arc striking is stable in real time. Therefore, a strategy is needed to dynamically correct the intelligent control of the arc striking process by integrating multiple source signals. First, analyze the actual change of the temperature under the arc characteristics of the workpiece to be welded, and evaluate the temperature adjustability. Second, analyze the accuracy of the temperature measurement data of the workpiece to be welded, and evaluate the error range of the current temperature. Finally, integrate the multi-source analysis results to accurately control the laser temperature, so as to correct the temperature measurement results in the preheating stage and provide accurate data support for the subsequent arc striking operation.

[0107] To this end, as shown in Figure 5 The arc striking control module 140 further includes the following units: a control analysis unit 141, an error analysis unit 142, and a temperature value determination unit 143.

[0108] The control analysis unit 141 is configured to obtain a current arc characteristic value of the workpiece to be welded, and obtain a temperature control amplitude of the workpiece to be welded according to the data correlation index of the arc striking plate, the current arc characteristic value of the workpiece to be welded, and the actual temperature data at the current time, in combination with the correlation between the temperature data and the arc characteristic value of each weld of the arc striking plate.

[0109] When the arc is ignited in the weld joint between the workpiece to be welded and the arc plate, the mathematical model of the action relationship between the laser spot temperature and the arc characteristics is pre-constructed. The theoretical value of the current laser spot temperature of the workpiece to be welded is determined under the arc characteristics of the current preheating stage of the workpiece to be welded. When there is a difference between the measured temperature and the theoretical value, the temperature adjustment degree can be used as the control input. At the same time, the temperature adjustment range obtained from the action relationship between the laser spot temperature and the arc characteristics needs to be limited according to the correlation between the arc characteristics and the temperature to prevent over-adjustment.

[0110] Based on this, the first step is to determine the current arc characteristic value of the workpiece to be welded based on the distribution of the actual arc data of the workpiece to be welded and the analysis of the actual temperature data.

[0111] It should be noted that based on the actual arc data of the workpiece to be welded, the current arc characteristic value of the workpiece to be welded can be determined according to the acquisition method of the arc characteristic value of each weld joint of the arc plate in the feature analysis unit 121. The current arc characteristic value represents the actual arc characteristics of the workpiece to be welded in the current preheating stage.

[0112] The second step is to determine the temperature difference coefficient as the difference between the product of the data correlation index of the arc plate and the current arc characteristic value and the actual temperature data at the current time.

[0113] The data correlation index G of the arc plate is constructed by historical statistical data to accurately determine the correlation between the temperature data and the arc characteristics, that is, when the arc characteristics are good, what is the temperature. The current arc characteristic value H of the workpiece to be welded is a direct reflection of the arc quality in the current monitoring stage. The arc characteristics can reflect whether the arc is stable in real time, and is a direct manifestation of whether the preheating condition meets the arc breakdown requirement. The larger the value of the current arc characteristic value H, the better the arc state of the current workpiece to be welded, and the closer the preheating temperature to the optimal arc temperature. The smaller the value of the current arc characteristic value H, the worse the arc state of the workpiece to be welded.

[0114] Based on this, the preheating temperature that should theoretically exist under the current arc state is deduced through the correlation between the historical data (the data correlation index G of the arc plate) and the current arc state of the workpiece to be welded (the current arc characteristic value H). This temperature value is a theoretical calculation value based on reliable arc signals and can be used for comparison with the measured temperature to determine whether the measured temperature is distorted.

[0115] More specifically, the product of the data correlation index G of the arc striking plate and the current arc characteristic value H of the workpiece to be welded represents the theoretical temperature value of the workpiece to be welded at the current preheating stage, the actual temperature data at the current time represents the measured temperature value at the latest time in the laser-assisted preheating stage, and the difference between the two represents the possible error degree of the laser spot temperature. That is, the temperature difference coefficient represents the difference between the laser spot temperature determined by the action relationship between the temperature of the workpiece to be welded and the arc characteristic and the actual temperature measurement result of the workpiece to be welded, which represents the possible error value of the temperature.

[0116] In the third step, the absolute value of the Pearson correlation coefficient between the arc characteristic value and the temperature data of each weld of the arc striking plate is taken as the correlation coefficient.

[0117] It should be noted that the temperature data of each weld of the arc striking plate corresponds to multiple time points, and each weld corresponds to an arc characteristic value. In order to unify the data dimensions, the mean value of the temperature data of all time points of each weld of the arc striking plate is taken as the temperature characteristic value of each weld. Further, according to the arrangement order of the welds on the arc striking plate, the temperature characteristic values of all the welds form a temperature characteristic sequence, and the arc characteristic values of all the welds form an arc characteristic sequence, and the absolute value of the Pearson correlation coefficient between the temperature characteristic sequence and the arc characteristic sequence is the correlation coefficient.

[0118] The correlation coefficient represents the correlation between the laser spot temperature and the arc characteristic at multiple welds of the arc striking plate. The closer the absolute value of the Pearson correlation coefficient is to 1, the greater the correlation between the temperature characteristic sequence and the arc characteristic sequence, and the closer the value is to 0, the smaller the correlation between the temperature characteristic sequence and the arc characteristic sequence. By involving the correlation coefficient in the calculation process of the temperature adjustable degree, the data evaluation result can be more accurate.

[0119] In the fourth step, the product between the temperature difference coefficient and the correlation coefficient is taken as the temperature regulation amplitude of the workpiece to be welded.

[0120] The temperature difference coefficient represents the possible error value of the temperature determined from the arc characteristic, and on this basis, the correlation between the arc characteristic and the temperature is limited, so that the evaluation result of the temperature adjustment degree of the current workpiece to be welded is more accurate, that is, the temperature regulation amplitude of the workpiece to be welded can achieve the purpose of dynamic improvement of feedback accuracy.

[0121] The error analysis unit 142 is configured to determine the product between the negative correlation coefficient of the accuracy index and the actual temperature data of the workpiece to be welded at the current time as the temperature error value of the workpiece to be welded.

[0122] In the unit, the temperature range can be adjusted through the accuracy analysis of the actual measurement result of the laser spot temperature of the to-be-welded piece. If the accuracy of the actual measurement result of the temperature of the to-be-welded piece is smaller, it indicates that the temperature data confidence of the current preheating stage is smaller, and then the space of the temperature adjustment of the current to-be-welded piece is larger. If the accuracy of the actual measurement result of the temperature of the to-be-welded piece is larger, it indicates that the temperature data confidence of the current preheating stage is larger, and then the space of the temperature adjustment of the current to-be-welded piece is smaller.

[0123] It should be noted that in the embodiment, the value range of the accuracy index is (0, 1), which can be represented by to represent the negative correlation coefficient of the accuracy index, and then to represent the temperature error value of the to-be-welded piece, wherein, represents the accuracy index corresponding to the to-be-welded piece, represents the temperature data of the to-be-welded piece at the current moment.

[0124] The temperature value determination unit 143 is configured to obtain the temperature input value of the laser-assisted preheating of the to-be-welded piece according to the temperature regulation amplitude and the temperature error value, and in combination with the actual temperature data of the to-be-welded piece.

[0125] In the unit, the temperature adjustment value obtained through the action relationship between the laser spot temperature and the arc characteristic is combined with the accuracy evaluation of the measured laser temperature to dynamically adjust the feedback data input of the control and improve the reliability of the arc striking control.

[0126] The product of the temperature regulation amplitude and the temperature error value and the accumulation sum between the actual temperature data of the to-be-welded piece at the current moment are taken as the temperature input value of the laser-assisted preheating of the to-be-welded piece.

[0127] The product of the temperature regulation amplitude and the temperature error value represents the temperature adjustment value of the laser spot temperature of the to-be-welded piece. Further, the accumulation sum between the temperature adjustment value and the temperature data of the to-be-welded piece at the current moment represents the temperature input value obtained through the adjustment according to the current sensor monitoring laser spot temperature, that is, the result of the temperature input adjustment on the basis of the measured temperature.

[0128] Finally, the temperature input value of the to-be-welded piece is input to the PID control module of the laser-assisted heating. The PID controller dynamically adjusts the laser power output according to the comprehensive action of the proportional, integral and differential three links, so that the workpiece temperature quickly and stably approaches the temperature input value, and the temperature regulation purpose is achieved. The PID control technology is known, and will not be described in detail here.

[0129] Further, the temperature input value is deviated from the preset arc striking condition temperature in the current scene to obtain a temperature deviation value, and when the temperature deviation value is less than a preset deviation threshold, the system determines that the preheating temperature state at this time meets the arc striking requirement, that is, the surface temperature of the workpiece to be welded has met the arc breakdown condition, and the arc striking operation can be performed. At this time, the control system immediately issues an arc striking instruction to start the welding machine power supply to establish the arc.

[0130] It should be noted that the arc striking condition temperature refers to the target temperature of the preheating temperature meeting the arc striking requirement, and the deviation threshold refers to the range allowed to deviate from the target temperature. For example, the deviation threshold is 2℃, which means that when the surface laser spot temperature of the workpiece to be welded is within the distribution range of the target temperature ± 2℃, it indicates that the current surface temperature of the workpiece to be welded meets the arc striking requirement and the arc striking operation can be performed. The arc striking condition temperature, that is, the target temperature and the deviation threshold, need to be set by relevant staff according to the specific implementation scene.

[0131] In other embodiments, the arc current and voltage waveform can also be monitored in real time to determine whether the arc striking is successful. This part is not the focus of the present application and will not be described here.

[0132] In other embodiments, the arc establishment success or failure can also be monitored in real time to give an early warning of the failure state. If the arc is successfully established, the system enters the normal welding stage and keeps monitoring the welding state. If the arc striking fails, the system immediately terminates the operation and triggers an alarm, records the arc characteristics and temperature data of the arc striking failure, and then adjusts the laser power, preheating time and other parameters to optimize the next arc striking control strategy, thereby improving the overall arc striking success rate. This part is not the focus of the present application and will not be described here.

[0133] In summary, the embodiment of the present application can identify the temperature measurement distortion problem caused by reflected light or arc light interference in advance by collecting the laser preheating temperature in the arc striking plate spliced weld area and verifying its accuracy, avoid the control algorithm relying on false data, and thus reduce the control error. By monitoring and analyzing the dynamic changes of the arc voltage and current at the moment of arc striking, the arc characteristics are used as a supplementary signal to make up for the deficiency when the temperature feedback is disturbed. By collecting and analyzing the data of multiple welds, the regular relationship between the temperature and the arc characteristics can be identified, and the control deviation caused by single point error can be reduced. When the accuracy of the temperature signal decreases, the arc characteristics are introduced as an auxiliary signal to construct a joint feedback, realize the dynamic correction of the arc striking stage control strategy, improve the fault tolerance and intelligent level of the arc striking control system, significantly improve the arc striking success rate, reduce the arc striking defects, and ensure the welding quality and process stability.

[0134] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A smart arc-starting system based on laser-assisted preheating, characterized in that, The system includes: The data acquisition module is used to acquire the temperature data, arc data and laser power data of the weld seam at each moment during the laser heating process of the arc-starting plate, and at the same time acquire the actual temperature data, actual arc data and actual laser power data of the workpiece to be welded during laser preheating; The correlation analysis module is used to analyze the relationship between arc characteristics and temperature changes based on the distribution of arc data and temperature data of the arc-starting plate weld, and to obtain the data correlation index of the arc-starting plate. The accuracy analysis module is used to obtain the accuracy index of the preheating temperature of the workpiece based on the difference in the distribution between the temperature data and laser power data of the arc-starting plate weld and the distribution between the actual temperature data and actual laser power data of the workpiece to be welded. The arc ignition control module is used to control the actual temperature data of the workpiece to be welded based on the data correlation index and accuracy index, combined with the interaction between the actual temperature data and the actual arc data, and to perform arc ignition operation on the workpiece to be welded based on the temperature control result.

2. The intelligent arc-starting system based on laser-assisted preheating according to claim 1, characterized in that, The correlation analysis module includes: The feature analysis unit is used to obtain the arc characteristic value of the arc-starting plate weld based on the differences in arc data of adjacent time sequences and the range distribution of arc data. The correlation determination unit is used to obtain the data correlation index of the arc-starting plate based on the correlation between the temperature data of the arc-starting plate weld and the arc characteristic value.

3. The intelligent arc-starting system based on laser-assisted preheating according to claim 2, characterized in that, The arc-starting plate contains at least two welds; The feature analysis unit is used for: Based on the balance of the differences between the arc data of each weld seam of the arc-starting plate at two adjacent moments, a first difference coefficient is determined; the range of the arc data of each weld seam of the arc-starting plate at all moments is determined as a second difference coefficient. The difference between the maximum value of the arc data for each weld of the arc-starting plate and the mean value of all arc data for that weld is determined as the third difference coefficient. The product of the first difference coefficient, the second difference coefficient, and the third difference coefficient is negatively correlated to obtain the arc characteristic value of each weld seam on the arc-starting plate.

4. The intelligent arc-starting system based on laser-assisted preheating according to claim 3, characterized in that, The correlation determination unit is used for: Based on the ratio between the temperature data of each two adjacent welds at the initial moment and the difference between the arc characteristic values, the data correlation index of the arc-starting plate is determined.

5. The intelligent arc-starting system based on laser-assisted preheating according to claim 3, characterized in that, The accuracy analysis module includes: The relationship determination unit is used to obtain the dynamic change relationship between temperature and laser power at each weld of the arc-starting plate based on the difference distribution between temperature data and laser power data of each weld of the arc-starting plate. The accuracy determination unit is used to obtain the accuracy index of the preheating temperature of the workpiece to be welded based on the difference between the dynamic change relationship corresponding to the workpiece to be welded and the dynamic change relationship corresponding to each weld seam of the arc-starting plate.

6. The intelligent arc-starting system based on laser-assisted preheating according to claim 5, characterized in that, The relationship determination unit is used for: Based on the standardized processing results of the temperature data of each weld seam of the arc-starting plate, a standard temperature sequence of each weld seam of the arc-starting plate is constructed. Based on the standardized processing results of the laser power data of each weld seam of the arc-starting plate, a standard laser sequence of each weld seam of the arc-starting plate is constructed. By negatively correlating the difference between the standard temperature sequence and the standard laser sequence for each weld, the dynamic relationship between the temperature and laser for each weld is obtained.

7. The intelligent arc-starting system based on laser-assisted preheating according to claim 5, characterized in that, The accuracy determination unit is used for: The negative correlation between the dynamic change relationship of the workpiece to be welded and the mean of the dynamic change relationship of all welds on the arc-starting plate is used as the accuracy index of the preheating temperature of the workpiece to be welded.

8. The intelligent arc-starting system based on laser-assisted preheating according to claim 3, characterized in that, The arc-starting control module includes: The control and analysis unit is used to obtain the current arc characteristic value of the workpiece to be welded. Based on the data correlation index of the arc-starting plate, the current arc characteristic value of the workpiece to be welded, and the actual temperature data at the current moment, combined with the correlation between the temperature data of each weld seam of the arc-starting plate and the arc characteristic value, the temperature control range of the workpiece to be welded is obtained. The error analysis unit is used to determine the temperature error value of the workpiece by multiplying the negative correlation coefficient of the accuracy index with the actual temperature data of the workpiece at the current moment. The temperature value determination unit is used to obtain the temperature input value for laser-assisted preheating of the workpiece to be welded based on the temperature control range and temperature error value, combined with the actual temperature data of the workpiece to be welded.

9. The intelligent arc-starting system based on laser-assisted preheating according to claim 8, characterized in that, The regulation and analysis unit is used for: The absolute value of the Pearson correlation coefficient between the arc characteristic value and temperature data of each weld seam on the arc-starting plate is used as the correlation coefficient. Based on the distribution of actual arc data and the analysis of actual temperature data of the workpiece to be welded, the current arc characteristic value of the workpiece to be welded is determined; The difference between the product of the data correlation index of the arc-starting plate and the current arc characteristic value and the actual temperature data at the current moment is determined as the temperature difference coefficient; The product of the temperature difference coefficient and the correlation coefficient is used as the temperature control range of the workpiece to be welded.

10. The intelligent arc-starting system based on laser-assisted preheating according to claim 8, characterized in that, The temperature value determination unit is used for: The sum of the product of the temperature control amplitude and the temperature error value and the actual temperature data of the workpiece at the current moment is used as the temperature input value for laser-assisted preheating of the workpiece.

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