Welding current and voltage automatic control method and system based on system model

Abstract

The invention relates to the technical field of electronic information, and particularly discloses a welding current and voltage automatic control method and system based on a system model, and the method comprises the steps: obtaining an actual welding current data value and a voltage data value based on image processing, and obtaining a welding current and voltage target value based on actual welding current and voltage information and preset welding current and voltage target values; the method comprises the following steps: obtaining a welding current and voltage deviation data value, obtaining a control pulse number for adjusting current and voltage according to the welding current and voltage deviation data value, obtaining rotation angle data for adjusting current and voltage of a stepping motor based on the control pulse number, and adjusting system characteristics according to the rotation angle data and a current and voltage knob. By means of the method, automatic adjustment and control over the welding current and the welding voltage can be achieved, the actual welding current and the actual welding voltage can rapidly reach target values, the labor intensity of workers is lowered, and the welding quality and efficiency are improved.

Description

Technical Field

[0001] The present application relates to the field of electronic information technology, and in particular to a welding current and voltage automatic control method and system based on a system model. Background Art

[0002] Welding current and voltage are the main process parameters that determine the welding quality. When the welding current increases, the weld depth and residual height will increase, while the weld width will not change much. This is because after the current increases, the arc force and heat input on the workpiece will increase, and the heat source position will move downward, resulting in an increase in the weld depth; at the same time, the amount of wire melted increases, and since the weld width does not change much, the residual height also increases accordingly, that is, the welding current directly affects the welding speed and the weld depth; the welding voltage affects the stability of the arc and the weld width. When the arc voltage increases, its arc power increases, the heat input of the workpiece increases, and the arc length is lengthened, the distribution radius increases, and thus the weld width increases; the voltage affects the welding arc length and the ejection speed of the molten droplet, thereby affecting the weld morphology. Therefore, during welding, only when the welding current matches the welding voltage can the welding arc be stable and the weld be beautiful.

[0003] In some manual welding equipment or automatic welding by machines, when welding current deviation and / or welding voltage deviation occurs, the traditional method often requires manual adjustment of the welding current and voltage. However, during manual adjustment, the welding current and voltage cannot be automatically adjusted to the target value quickly and accurately, thereby affecting the welding efficiency and welding quality. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a welding current and voltage automatic control method and system based on a system model.

[0005] In a first aspect, an embodiment of the present application provides a method for automatic control of welding current and voltage based on a system model, the method comprising: Acquire image information of welding current and voltage indications, and obtain actual welding current data value and voltage data value based on the image information; Based on the actual welding current data value and voltage data value and the preset welding current target value and voltage target value, a welding current deviation data value and a welding voltage deviation data value are obtained; According to the welding current deviation data value and the welding voltage deviation data value, respectively obtaining a first control pulse number and a second control pulse number corresponding to the stepping motor for adjusting current and voltage; Based on the first control pulse number and the second control pulse number, obtaining the rotation angle data of the stepping motor for adjusting the current and voltage; According to the rotation angle data and the characteristics of the current and voltage knob adjustment system, the actual welding current data value and voltage data value are automatically corrected and controlled in a closed loop.

[0006] In some possible examples, obtaining the first control pulse number and the second control pulse number corresponding to the stepper motor for adjusting the current and the voltage respectively according to the welding current deviation data value and the welding voltage deviation data value includes: Obtain the linear proportional coefficients of the motor rotation angle, welding current change, welding voltage change, and PID proportional link coefficients; Based on the linear proportional coefficient, the proportional link coefficient and the proportional link coefficient of the PID, a first mathematical model for controlling the number of pulses and the welding current and voltage deviation of the stepper motor is constructed; Based on the first mathematical model, the welding current deviation data value and the welding voltage deviation data value, a first control pulse number and a second control pulse number corresponding to the stepper motor for adjusting current and voltage are obtained.

[0007] In some possible embodiments, the first mathematical model for controlling the number of pulses and welding current and voltage deviations of the stepper motor rotation based on the linear proportional coefficient, the proportional link coefficient and the proportional link coefficient of the PID is constructed, including: Create a relationship between the number of pulses used to control the rotation of the stepper motor and the welding current deviation and welding voltage deviation, where the relationship is: In the formula, To adjust the number of control pulses corresponding to the stepper motor current, The number of control pulses corresponding to the stepper motor to adjust the voltage, is the coefficient of the proportional link of PID, is the welding current deviation, is the welding voltage deviation, Km is the relationship between the stepper motor output and input, Kd is the relationship between the driver output and input, When adjusting the welding current, the linear proportional coefficient between the motor rotation angle and the welding current change is To adjust the welding voltage, the linear proportional coefficient between the motor rotation angle and the welding voltage change, Indicates the number of pulses required for the driver to drive the stepper motor to rotate 360°.

[0008] In some possible examples, obtaining the rotation angle data of the stepper motor for adjusting the current and voltage based on the first control pulse number and the second control pulse number includes: According to the relationship between the output and input of the stepper motor and the driver, and the driver output corresponding to the stepper motor for adjusting current and adjusting voltage, a second mathematical model of the driver and stepper motor system is constructed; The first control pulse number and the second control pulse number are input into the second mathematical model to obtain the rotation angle data of the stepping motor regulating current and regulating voltage respectively.

[0009] In some examples that may be implemented, the second mathematical model of the driver and stepper motor system is constructed according to the relationship between the output and input of the stepper motor and the driver, and the driver output corresponding to the stepper motor for adjusting current and adjusting voltage, including: According to the relationship between the output and input of the stepper motor and the driver, and the driver output corresponding to the stepper motor for adjusting current and adjusting voltage, a calculation relationship corresponding to the rotation angle data of the stepper motor is created, wherein the calculation relationship is: In the formula, To adjust the current of the stepper motor, To adjust the voltage of the stepper motor, Km Represents the relationship between the stepper motor output and input, Kd Indicates the relationship between the driver output and input, To adjust the current of the stepper motor corresponding to the output of the driver, To adjust the voltage of the stepper motor corresponding to the output of the driver, To adjust the number of control pulses corresponding to the stepper motor current, The number of control pulses corresponding to the stepper motor to adjust the voltage, Indicates the number of pulses required for the driver to drive the stepper motor to rotate 360°.

[0010] In some possible examples, the closed-loop automatic correction control of the actual welding current data value and the voltage data value according to the rotation angle data and the current and voltage knob adjustment system characteristics includes: Based on the characteristics of the current and voltage knob adjustment system, the relationship between the actual welding current data value and the voltage data value and the rotation angle of the adjustment knob is created respectively, where the relationship is: In the formula, is the actual welding current, is the previous actual welding current, is the actual welding voltage at present, is the actual welding voltage of the previous time, Model representing the current and voltage knob adjustment system. It represents the linear proportional coefficient of the relationship between the motor rotation angle and the welding current change when adjusting the welding current. It represents the linear proportional coefficient of the relationship between the motor rotation angle and the welding voltage change when adjusting the welding voltage. To adjust the current of the stepper motor, To adjust the voltage of the stepper motor, A nonlinear polynomial that represents the relationship between the motor rotation angle that regulates the current and the change in welding current, A nonlinear polynomial that represents the relationship between the motor rotation angle for regulating the voltage and the change in welding voltage, is the welding current deviation, is the welding voltage deviation, To adjust the motor's rotation speed for the current, The voltage regulates the motor's rotation speed. The maximum motor speed when the motor rotation angle and the change in current or voltage are linearly related when the two parameters are adjusted simultaneously. The maximum motor rotation speed when only a single parameter is adjusted and the motor rotation angle is linearly related to the change in current or voltage.

[0011] In some possible examples, the closed-loop automatic correction control of the actual welding current data value and the voltage data value according to the rotation angle data and the current and voltage knob adjustment system characteristics also includes: Create a relationship between the motor rotation speed during the welding current and welding voltage speed adjustment process, where: Current regulates motor speed The relationship is: Voltage regulation of motor speed The relationship is: In the formula, To find the absolute value of a function, is the welding current deviation, is the welding voltage deviation, The maximum motor speed when the motor rotation angle and the change in current or voltage are linearly related when the two parameters are adjusted simultaneously. The maximum motor rotation speed when only a single parameter is adjusted and the motor rotation angle and the change in current or voltage are in a linear relationship; The motor rotation speed is adjusted based on the current Relationship and voltage regulation of motor rotation speed The actual welding current data value and the voltage data value are adjusted to the target welding current and the target welding voltage.

[0012] In a second aspect, an embodiment of the present application provides a control system corresponding to a welding current and voltage automatic control method based on a system model as described above, characterized in that the system comprises: An acquisition module is configured to acquire image information of welding current and voltage indications through a visual sensor, and obtain actual welding current data value and voltage data value based on the image information; A first data processing module is configured to obtain a welding current deviation data value and a welding voltage deviation data value based on the actual welding current data value and the voltage data value and a preset welding current target value and a preset voltage target value; A second data processing module is configured to obtain a first control pulse number and a second control pulse number corresponding to a stepper motor for adjusting current and voltage, respectively, based on the welding current deviation data value and the welding voltage deviation data value and based on a PID control algorithm; A third data processing module, based on the first control pulse number and the second control pulse number, obtains the rotation angle data of the stepping motor for adjusting the current and voltage; The fourth data processing module is configured to perform closed-loop automatic correction control on the actual welding current data value and voltage data value according to the relationship between the actual welding current data value and voltage data value and the knob rotation angle, and the welding current and voltage speed adjustment method.

[0013] Compared with the prior art, the technical solution provided by the embodiment of the present invention includes at least the following beneficial effects: 1) The welding current and voltage automatic correction control method of the present application uses an image processing method to identify the actual welding current and the actual welding voltage, compares them with the target welding current and the target welding voltage, obtains the welding current deviation and the welding voltage deviation, and builds a first mathematical model for controlling the number of pulses for the rotation of the stepper motor and the welding current and voltage deviation. Based on the first mathematical model, the first control pulse number and the second control pulse number corresponding to the stepper motor for adjusting the current and the voltage are obtained. Then, the first control pulse number for adjusting the current and the second control pulse number for adjusting the voltage are used as the input of the mathematical model of the driver and the stepper motor system and the mathematical model of the current and voltage knob adjustment system. A method for automatically and accurately adjusting the deviation between the actual welding current and the welding voltage and the preset target welding current and the welding voltage is realized, so as to avoid the mismatch between the welding current and the welding voltage during the adjustment process, and realize the synchronous, rapid and accurate automatic adjustment of the welding current and the voltage to the target value, thereby improving the welding efficiency and welding quality.

[0014] 2) Since the current and voltage knob adjustment system requires a certain reaction time, when the welding current and voltage are adjusted too quickly, the change in welding current and voltage is nonlinear with the angle of motor rotation. In addition, when the welding voltage and welding current are adjusted quickly at the same time, there is mutual influence. Based on the characteristics of the current and voltage knob adjustment system, a mathematical model of the actual welding current data value and voltage data value and the adjustment knob rotation angle is created, as well as a current adjustment motor rotation speed is created. And voltage regulation motor speed The mathematical model is created to control the speed of the stepper motor, so that the welding current and voltage knob adjustment system works as a linear model, and the target welding current and target welding voltage can be adjusted quickly and accurately.

[0015] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 is a flow chart of a welding current and voltage automatic control method based on a system model according to an embodiment of the present application; Figure 2 is a diagram of an actual device corresponding to the control method according to an embodiment of the present application; Figure 3 is another flow chart of a welding current and voltage automatic control method based on a system model according to an embodiment of the present application; Figure 4 is a curve showing the change of the actual and target welding currents during the adjustment process according to an embodiment of the present application; Figure 5 is a curve showing the change of the actual and target welding voltages during the adjustment process according to an embodiment of the present application; Figure 6 is a block diagram of a welding current and voltage automatic control system based on a system model according to an embodiment of the present application; DETAILED DESCRIPTION The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0018] It should be noted that, unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0019] See also Figures 1 to 5 This embodiment provides a welding current and voltage automatic control method and system based on a system model, the method comprising: Step S100: Acquire image information of welding current and voltage indications, and identify actual welding current data values ​​and voltage data values ​​based on the image information; First, it should be noted that the welding current and voltage automatic correction control method of this embodiment can be applied to a variety of improved welding devices, such as Figure 2 As shown, Figure 2 One of the welding equipment devices corresponding to the welding current and voltage automatic correction control method provided in this embodiment is shown, wherein the device may include related components such as a controller, a driver, a stepper motor and a visual sensor, two stepper motors are used for current and voltage knob adjustment respectively, and the driver is used to realize automatic control of the stepper motor. The welding current and voltage automatic control method of this embodiment is described in detail below based on the improved device.

[0020] In the step, the image information of the welding current and voltage indications can be collected by components such as visual sensors or cameras, and the actual welding current data value and voltage data value can be obtained by automatically identifying the collected image information through image processing. It should be noted that image processing is a relatively mature technology, and the specific principles of image processing and how to extract information from the image are not described in detail here; Of course, in a possible example, image processing technology may not be used as a source for obtaining the actual welding current data value and voltage data value. For example, the actual welding current data value and voltage data value displayed on the wire feeder may be directly read through information transmission. The specific selection can be made based on actual needs and is not limited here.

[0021] Step S200: obtaining a welding current deviation data value and a welding voltage deviation data value based on the actual welding current data value and the voltage data value and the preset welding current target value and the voltage target value; In this step, combine Figure 3 As shown, the actual welding current collected And the actual welding voltage , and compare it with the target welding current and target welding voltage By comparison, the welding current deviation can be obtained. And welding voltage deviation It should be noted that in this step, the target welding current and target welding voltage The welding current deviation can be set by electronic equipment with data processing capabilities, such as a computer or a computer. And welding voltage deviation It can be obtained through addition and subtraction operations in electronic devices, and the specific implementation principle will not be described here.

[0022] Step S300: obtaining a first control pulse number and a second control pulse number corresponding to a stepping motor for adjusting current and voltage respectively according to the welding current deviation data value and the welding voltage deviation data value; In this step, continue to combine Figure 3 As shown, the linear proportional coefficient of the motor rotation angle and the welding current change, the welding voltage change and the proportional link coefficient of the PID are obtained; based on the linear proportional coefficient, the proportional link coefficient and the proportional link coefficient of the PID, a first mathematical model for controlling the number of pulses and the welding current and voltage deviations of the stepper motor is established; based on the first mathematical model, the welding current deviation data value and the welding voltage deviation data value, the first control pulse number and the second control pulse number corresponding to the stepper motor for adjusting the current and voltage are obtained. It should be noted that the first mathematical model is used to convert the welding current deviation and the welding voltage deviation into the number of pulses for controlling the rotation of the stepper motor, thereby controlling the rotation of the stepper motor by using the number of pulses as input.

[0023] Specifically, according to the characteristics of the controlled object model, the controller is designed to And welding voltage deviation As input, PID control algorithm is adopted, and the pulse number of the stepper motor rotation angle is output. According to the welding current and voltage speed adjustment method studied, the speed of the stepper motor rotation is controlled. In order to make the welding current and voltage knob adjustment system work as a linear model, and the experiment found that only the proportional link of PID can achieve a good control effect, the pulse number for controlling the rotation of the stepper motor can be established ( , ) and welding current deviation and welding voltage deviation ( , ), where the relationship is: In the formula, To adjust the number of control pulses corresponding to the stepper motor current, The number of control pulses corresponding to the stepper motor to adjust the voltage, is the coefficient of the proportional link of PID, is the welding current deviation, is the welding voltage deviation, Km is the relationship between the stepper motor output and input, Kd is the relationship between the driver output and input, When adjusting the welding current, the linear proportional coefficient between the motor rotation angle and the welding current change is To adjust the welding voltage, the linear proportional coefficient between the motor rotation angle and the welding voltage change, Indicates the number of pulses required for the driver to drive the stepper motor to rotate 360°.

[0024] Step S400: obtaining rotation angle data for adjusting current and voltage of the stepping motor based on the first control pulse number and the second control pulse number; In this step, a second mathematical model of the driver and stepper motor system is constructed based on the relationship between the output and input of the stepper motor and the driver, and the driver output corresponding to the stepper motor for adjusting current and adjusting voltage; the first control pulse number and the second control pulse number are input into the second mathematical model to obtain the rotation angle data of the stepper motor for adjusting current and adjusting voltage, respectively.

[0025] It should be noted that the above-mentioned first mathematical model and second mathematical model, first control pulse number and second control pulse number are only for the convenience of distinguishing expressions, and do not represent the same meaning of the relationship. For example, the second mathematical model is actually used to express the data control and adjustment relationship between the driver and the stepper motor system.

[0026] Furthermore, the second mathematical model of the driver and stepper motor system specifically includes that the controller can control the rotation angle of the stepper motor through the driver, and the number of pulses sent by the controller ( , ) and the angle of rotation of the stepper motor ( , ) satisfies the following formula, and according to the relationship between the output and input of the stepper motor and the driver, and the driver output corresponding to the stepper motor for adjusting current and adjusting voltage, a calculation formula for the stepper motor corresponding to the rotation angle data is created, wherein the calculation formula is: In the formula, To adjust the current of the stepper motor, To adjust the voltage of the stepper motor, Km Represents the relationship between the stepper motor output and input, Kd Indicates the relationship between the driver output and input, To adjust the current of the stepper motor corresponding to the output of the driver, To adjust the voltage of the stepper motor corresponding to the output of the driver, To adjust the number of control pulses corresponding to the stepper motor current, The number of control pulses corresponding to the stepper motor to adjust the voltage, Indicates the number of pulses required for the driver to drive the stepper motor to rotate 360°, where: .

[0027] Step S500: performing closed-loop automatic correction control on the actual welding current data value and voltage data value according to the rotation angle data and the current and voltage knob adjustment system characteristics.

[0028] In this step, it should be noted that when creating the mathematical model of the current and voltage knob adjustment system, it was found through experiments that the current and voltage knob adjustment system has the following characteristics: when the current or voltage adjustment motor rotates at a speed lower than f max When the motor rotates, the current and voltage knobs rotate to adjust the welding current and voltage, and the motor rotation angle is linearly related to the change in current or voltage. When the current-adjusting motor rotates 15 degrees each time, the actual welding current changes by 2 A; when the voltage-adjusting motor rotates 15 degrees each time, the actual welding voltage changes by 0.2 V.

[0029] However, since the current and voltage knob adjustment system requires a certain amount of reaction time, when the welding current and voltage are adjusted too quickly, the change in welding current and voltage is nonlinear with the motor rotation angle. In addition, when the welding voltage and welding current are adjusted quickly at the same time, there is mutual influence. When only a single parameter is adjusted, the maximum motor rotation speed at which the motor rotation angle is linearly related to the change in current or voltage is f max (The motor rotates 1 circle in 2.5 seconds). When the two parameters are adjusted at the same time, the maximum motor rotation speed with a linear relationship between the motor rotation angle and the change in current or voltage is f min (The motor rotates 1 circle in 5 seconds), so the maximum speed when the two parameters are adjusted at the same time f min Approximately the maximum speed when a single parameter is adjusted f max half.

[0030] According to the characteristics of the current and voltage knob adjustment system mentioned above, a mathematical model of the current and voltage knob adjustment system can be established, that is, the actual welding current and voltage The relationship between the actual welding current data value and voltage data value and the adjustment knob rotation angle is as follows: In the formula, is the actual welding current, is the previous actual welding current, is the actual welding voltage at present, is the actual welding voltage of the previous time, Model representing the current and voltage knob adjustment system. It represents the linear proportional coefficient of the relationship between the motor rotation angle and the welding current change when adjusting the welding current. It represents the linear proportional coefficient of the relationship between the motor rotation angle and the welding voltage change when adjusting the welding voltage. To adjust the current of the stepper motor, To adjust the voltage of the stepper motor, A nonlinear polynomial that represents the relationship between the motor rotation angle that regulates the current and the change in welding current, A nonlinear polynomial that represents the relationship between the motor rotation angle for regulating the voltage and the change in welding voltage, is the welding current deviation, is the welding voltage deviation, To adjust the motor's rotation speed for the current, The voltage regulates the motor's rotation speed. The maximum motor speed when the motor rotation angle and the change in current or voltage are linearly related when the two parameters are adjusted simultaneously. The maximum motor rotation speed when only a single parameter is adjusted and the motor rotation angle is linearly related to the change in current or voltage.

[0031] It should be noted that the linear proportionality coefficient of the relationship between the motor rotation angle and the welding current change when adjusting the welding current is , and the linear proportionality coefficient of the relationship between the motor rotation angle and the welding voltage change when adjusting the welding voltage ,satisfy , When the two parameters are adjusted simultaneously, the maximum motor rotation speed when the motor rotation angle and the change in current or voltage are linearly related is 0.2 r / s. When only a single parameter is adjusted, the maximum motor rotation speed when the motor rotation angle and the change in current or voltage are in a linear relationship is 0.4 r / s.

[0032] Furthermore, in order to quickly and accurately adjust the target welding current and target welding voltage, the output characteristics of the current and voltage knob adjustment system are required to be linear, and the motor rotation speed is in the range [ f min , f max ] If the lowest speed is used f min If the highest speed is used, the target current and voltage cannot be adjusted quickly. f max If a single parameter is adjusted in sequence, the welding current and welding voltage will not match during the adjustment process, which will affect the welding quality. Therefore, the welding current and voltage variable speed adjustment method is adopted. When both current and voltage need to be adjusted, the lowest speed is used first. f min Adjust the current and voltage at the same time. After adjusting one of the parameters, use the maximum speed to adjust the parameter that has not been adjusted. f max Therefore, the welding current and voltage can be adjusted quickly by the following relationship.

[0033] Current regulates motor speed The relationship is: Voltage regulation of motor speed The relationship is: In the formula, To find the absolute value of a function, is the welding current deviation, is the welding voltage deviation, The maximum motor speed when the motor rotation angle and the change in current or voltage are linearly related when the two parameters are adjusted simultaneously. The maximum motor rotation speed when only a single parameter is adjusted and the motor rotation angle and the change in current or voltage are in a linear relationship; Based on the above current, the motor rotation speed is adjusted Relationship and voltage regulation of motor rotation speed The actual welding current data value and voltage data value are automatically adjusted to the target welding current and target welding voltage.

[0034] In the above method steps, the actual welding current and the actual welding voltage are identified by an image processing method, and compared with the target welding current and the target welding voltage to obtain the welding current deviation and the welding voltage deviation. By building a first mathematical model for controlling the number of pulses for the rotation of the stepper motor and the welding current and voltage deviation, the first control pulse number and the second control pulse number corresponding to the stepper motor for adjusting the current and voltage are obtained based on the first mathematical model. Then, by using the first control pulse number for adjusting the current and the second control pulse number for adjusting the voltage as the input of the mathematical model of the driver and the stepper motor system, and the mathematical model of the current and voltage knob adjustment system, a method for automatically and accurately adjusting the deviation between the actual welding current and the welding voltage and the preset target welding current and welding voltage is realized, so as to avoid the mismatch between the welding current and the welding voltage during the adjustment process, and realize the synchronous, rapid and accurate automatic adjustment of the welding current and voltage to the target value, thereby improving the welding efficiency and welding quality.

[0035] In addition, since the current and voltage knob adjustment system requires a certain reaction time, when the welding current and voltage are adjusted too quickly, the change in welding current and voltage is nonlinearly related to the angle of rotation of the motor, and when the welding voltage and welding current are adjusted quickly at the same time, there is a mutual influence; and by creating a mathematical model of the actual welding current data value and voltage data value and the rotation angle of the adjustment knob according to the characteristics of the current and voltage knob adjustment system, and creating a current adjustment motor rotation speed And voltage regulation motor speed The mathematical model is created to control the speed of the stepper motor, so that the welding current and voltage knob adjustment system works as a linear model, and the target welding current and target welding voltage can be adjusted quickly and accurately.

[0036] In one example, see Figure 4 and Figure 5 , Figure 4 and Figure 5 The change curves of the actual and target welding currents and the change curves of the actual and target welding voltages during the control process using the above method steps are shown. Figure 4 and Figure 5 The ab segment in the figure indicates that before welding, when the welding machine is just turned on, the welding current is 140 A and the welding voltage is 15 V. First, the target value of the initial welding current is set to 200 A and the target value of the initial welding voltage is set to 21 V. Figure 2-3From point h in the figure, from point b to point c, the actual welding current and voltage quickly approach the target value. At point c, the actual current and voltage are equal to the set target current and voltage, completing the automatic and rapid adjustment of the initial welding current and voltage. Then, at point d, the arc is ignited and welding begins. Since the welding current and welding voltage in segment de do not match, the welding quality is poor. Finally, at the 49th sampling point, the corresponding Figure 4 and Figure 5 At point i in the figure, the target welding current is set to 230 A and the target welding voltage is set to 26 V. Through the invented welding current and voltage automatic control method, the actual welding current and voltage can quickly and accurately reach the target value, so that the weld is beautiful and the welding quality is good. Figure 4 and Figure 5 It can be found from the fg segment in that the accuracy of welding current detection and control is 100%, and the accuracy of welding voltage detection and control is 100%, which shows that the method of the present invention can improve the efficiency and quality of welding.

[0037] See also Figure 6 In some embodiments, a control system 200 for automatic correction control of welding current and voltage is provided, and the control system 200 includes: The acquisition module 210 is configured to acquire image information of welding current and voltage indications through a visual sensor, and obtain actual welding current data value and voltage data value based on the image information; The first data processing module 220 is configured to obtain a welding current deviation data value and a welding voltage deviation data value based on the actual welding current data value and the voltage data value and the preset welding current target value and the voltage target value; The second data processing module 230 is configured to obtain the first control pulse number and the second control pulse number corresponding to the stepping motor for adjusting the current and the voltage respectively based on the welding current deviation data value and the welding voltage deviation data value and based on the PID control algorithm; A third data processing module 240 obtains rotation angle data of the stepping motor for adjusting current and voltage based on the first control pulse number and the second control pulse number; The fourth data processing module 250 is configured to perform closed-loop automatic correction control on the actual welding current data value and voltage data value according to the relationship between the actual welding current data value and voltage data value and the knob rotation angle, and the welding current and voltage speed adjustment method.

[0038] The terms "first", "second", "third", etc. in the specification and claims of the present application and the drawings are used to distinguish different objects rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a series of steps or units are included, or optionally, steps or units not listed are included, or optionally, other steps or units inherent to these processes, methods, products or devices are included.

[0039] Only the part relevant to the present application is shown in the accompanying drawings, but not all of the content. Before discussing the exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processing or methods depicted as flow charts. Although the flow chart describes each operation (or step) as a sequential process, many of the operations therein can be implemented in parallel, concurrently or simultaneously. In addition, the order of each operation can be rearranged. When its operation is completed, the process can be terminated, but it can also have additional steps not included in the accompanying drawings. The process can correspond to a method, function, procedure, subroutine, subprogram, etc.

[0040] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0041] Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Mentioning "embodiment" in this article means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present embodiment application. The appearance of this phrase in various positions in the specification is not necessarily the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It can be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0042] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A welding current and voltage automatic control method based on a system model, characterized in that: The method comprises: Acquire image information of welding current and voltage indications, and obtain actual welding current data value and voltage data value based on the image information; Based on the actual welding current data value and voltage data value and the preset welding current target value and voltage target value, a welding current deviation data value and a welding voltage deviation data value are obtained; According to the welding current deviation data value and the welding voltage deviation data value, respectively obtaining a first control pulse number and a second control pulse number corresponding to the stepping motor for adjusting current and voltage; Based on the first control pulse number and the second control pulse number, obtaining the rotation angle data of the stepping motor for adjusting the current and voltage; According to the rotation angle data and the characteristics of the current and voltage knob adjustment system, the actual welding current data value and voltage data value are automatically corrected and controlled in a closed loop.

2. The welding current and voltage automatic control method based on the system model according to claim 1 is characterized in that: The method of obtaining the first control pulse number and the second control pulse number corresponding to the stepping motor for adjusting the current and the voltage according to the welding current deviation data value and the welding voltage deviation data value respectively comprises: Obtain the linear proportional coefficients of the motor rotation angle, welding current change, welding voltage change, and PID proportional link coefficients; Based on the linear proportional coefficient, the proportional link coefficient and the proportional link coefficient of the PID, a first mathematical model for controlling the number of pulses and the welding current and voltage deviation of the stepper motor is constructed; Based on the first mathematical model, the welding current deviation data value and the welding voltage deviation data value, a first control pulse number and a second control pulse number corresponding to the stepper motor for adjusting current and voltage are obtained.

3. The automatic control method of welding current and voltage based on system model according to claim 2 is characterized in that: The first mathematical model for controlling the number of pulses and welding current and voltage deviations of the stepper motor rotation based on the linear proportional coefficient, the proportional link coefficient and the proportional link coefficient of the PID is constructed, including: Create a relationship between the number of pulses used to control the rotation of the stepper motor and the welding current deviation and welding voltage deviation, where the relationship is: In the formula, To adjust the number of control pulses corresponding to the stepper motor current, The number of control pulses corresponding to the stepper motor to adjust the voltage, is the coefficient of the proportional link of PID, is the welding current deviation, is the welding voltage deviation, Km is the relationship between the stepper motor output and input, Kd is the relationship between the driver output and input, When adjusting the welding current, the linear proportional coefficient between the motor rotation angle and the welding current change is To adjust the welding voltage, the linear proportional coefficient between the motor rotation angle and the welding voltage change, Indicates the number of pulses required for the driver to drive the stepper motor to rotate 360°.

4. The welding current and voltage automatic control method based on the system model according to claim 1 is characterized in that: Based on the first control pulse number and the second control pulse number, the rotation angle data of the stepper motor adjusting the current and voltage is obtained, including: According to the relationship between the output and input of the stepper motor and the driver, and the driver output corresponding to the stepper motor for adjusting current and adjusting voltage, a second mathematical model of the driver and stepper motor system is constructed; The first control pulse number and the second control pulse number are input into the second mathematical model to obtain the rotation angle data of the stepping motor regulating current and regulating voltage respectively.

5. The automatic control method of welding current and voltage based on system model according to claim 4 is characterized in that: According to the relationship between the output and input of the stepper motor and the driver, and the driver output corresponding to the stepper motor for adjusting current and adjusting voltage, a second mathematical model of the driver and stepper motor system is constructed, including: According to the relationship between the output and input of the stepper motor and the driver, and the driver output corresponding to the stepper motor for adjusting current and adjusting voltage, a calculation relationship corresponding to the rotation angle data of the stepper motor is created, wherein the calculation relationship is: In the formula, To adjust the current of the stepper motor, To adjust the voltage of the stepper motor, Km Represents the relationship between stepper motor output and input, Kd Indicates the relationship between the driver output and input, To adjust the current of the stepper motor corresponding to the output of the driver, To adjust the voltage of the stepper motor corresponding to the output of the driver, To adjust the number of control pulses corresponding to the stepper motor current, The number of control pulses corresponding to the stepper motor to adjust the voltage, Indicates the number of pulses required for the driver to drive the stepper motor to rotate 360°.

6. The automatic control method of welding current and voltage based on system model according to claim 1, characterized in that: The closed-loop automatic correction control of the actual welding current data value and voltage data value is performed according to the rotation angle data and the current and voltage knob adjustment system characteristics, including: Based on the characteristics of the current and voltage knob adjustment system, the relationship between the actual welding current data value and the voltage data value and the rotation angle of the adjustment knob is created respectively, where the relationship is: In the formula, is the actual welding current, is the previous actual welding current, is the actual welding voltage at present, is the actual welding voltage of the previous time, Model representing the current and voltage knob adjustment system. It represents the linear proportional coefficient of the relationship between the motor rotation angle and the welding current change when adjusting the welding current. It represents the linear proportional coefficient of the relationship between the motor rotation angle and the welding voltage change when adjusting the welding voltage. To adjust the current of the stepper motor, To adjust the voltage of the stepper motor, A nonlinear polynomial that represents the relationship between the motor rotation angle that regulates the current and the change in welding current, A nonlinear polynomial that represents the relationship between the motor rotation angle for regulating the voltage and the change in welding voltage, is the welding current deviation, is the welding voltage deviation, To adjust the motor's rotation speed for the current, The voltage regulates the motor's rotation speed. The maximum motor speed when the motor rotation angle and the change in current or voltage are linearly related when the two parameters are adjusted simultaneously. The maximum motor rotation speed when only a single parameter is adjusted and the motor rotation angle is linearly related to the change in current or voltage.

7. The automatic control method of welding current and voltage based on system model according to claim 6, characterized in that: The method of performing closed-loop automatic correction control on the actual welding current data value and voltage data value according to the rotation angle data and the current and voltage knob adjustment system characteristics also includes: Create a relationship between the motor rotation speed during the welding current and welding voltage speed regulation process, where: Current regulates motor speed The relationship is: Voltage regulation of motor speed The relationship is: In the formula, To find the absolute value of a function, is the welding current deviation, is the welding voltage deviation, The maximum motor speed when the motor rotation angle and the change in current or voltage are linearly related when the two parameters are adjusted simultaneously. The maximum motor rotation speed when only a single parameter is adjusted and the motor rotation angle and the change in current or voltage are in a linear relationship; The motor rotation speed is adjusted based on the current Relationship and voltage regulation of motor rotation speed The actual welding current data value and the voltage data value are adjusted to the target welding current and the target welding voltage.

8. A control system corresponding to the welding current and voltage automatic control method based on a system model as claimed in any one of claims 1 to 7, characterized in that: The system comprises: An acquisition module is configured to acquire image information of welding current and voltage indications through a visual sensor, and obtain actual welding current data value and voltage data value based on the image information; A first data processing module is configured to obtain a welding current deviation data value and a welding voltage deviation data value based on the actual welding current data value and the voltage data value and a preset welding current target value and a preset voltage target value; A second data processing module is configured to obtain a first control pulse number and a second control pulse number corresponding to a stepper motor for adjusting current and voltage, respectively, based on the welding current deviation data value and the welding voltage deviation data value and based on a PID control algorithm; A third data processing module, based on the first control pulse number and the second control pulse number, obtains the rotation angle data of the stepping motor for adjusting the current and voltage; The fourth data processing module is configured to perform closed-loop automatic correction control on the actual welding current data value and voltage data value according to the relationship between the actual welding current data value and voltage data value and the knob rotation angle, and the welding current and voltage speed adjustment method.

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