Automatic welding control method

Abstract

The automatic welding control method is used for adjusting movement of automatic welding equipment, the automatic welding equipment comprises a rotating mechanism, a welding gun angle adjusting mechanism and a lifting movement mechanism and is used for welding a welding seam between a branch pipe and a main pipe, the branch pipe and the main pipe are not arranged in parallel, and the automatic welding control method comprises the following steps that an image vision system is adopted for collecting an existing welding seam image; extracting a weld edge contour, and drawing a weld characteristic curve; constructing a curved surface track function and a welding gun angle adjusting function according to the welding seam characteristic curve, wherein the curved surface track function comprises a rotary motion function and a lifting motion function; and the welding gun angle adjusting mechanism, the rotary mechanism and the lifting motion mechanism respectively move according to the angle adjusting function, the rotary motion function and the lifting motion function. According to the method, the automatic welding equipment can realize continuous and stable welding.

Description

Technical Field

[0001] The present invention relates to the field of welding, and particularly to the field of welding control methods. Background Art

[0002] Welding is a key technology in nuclear power plant construction. However, a large number of engineering welds in the process of nuclear power construction are still mainly manual operations. Especially for some complex weld trajectories involved in the pressurizer, reactor pressure vessel, steam generator, condenser, cooling tower, and transfer pipeline, due to the different weld angles at different spatial positions, the welding parameters also change during the welding process, increasing the difficulty of welding.

[0003] Automatic welding requires good recognition of the trajectory and attitude planning. Currently, the methods for solving weld trajectory planning welding mostly rely on teaching reproduction, recording the recognition process, and finally reproducing it during the welding process. Common welding automation methods mostly adjust the trajectory in the following ways. For example, through a 3D point cloud model, using D-H to establish a kinematic formula, establishing a mathematical model to solve the welding torch movement trajectory, a laser beam, etc. Among them, the point cloud model is to convert the three-dimensional point cloud coordinate system to the coordinate system of the welding robot, and the welding robot performs sequential displacements according to the coordinate points on the coordinate system to achieve the movement trajectory; using the D-H method to establish a kinematic formula means obtaining the attitude and coordinate position of the end of the welding robot in the base coordinate system of the welding robot to achieve the movement trajectory; establishing a mathematical model to solve means solving the discrete point coordinate positions on the three-dimensional complex welding trajectory through establishing a mathematical model, and enabling the motion mechanism to perform displacements according to the discrete points to achieve the control of the welding trajectory; the laser beam method means using the obtained welding trajectory data as the output of the laser welding device to perform welding trajectory planning.

[0004] The above methods all perform displacements based on multiple coordinate positions to achieve the movement trajectory, which is not continuous and accurate enough, resulting in the trajectory curve often being uneven and discontinuous, and easily causing impacts on the mechanical structure. In addition, the above methods also need to use multiple interpolation methods to improve the smoothness of the movement, which is relatively complex. Summary of the Invention

[0005] An object of the present invention is to provide an automatic welding control method that can enable an automatic welding device to achieve continuous and stable welding.

[0006] The automatic welding control method for achieving the above object is used to adjust the movement of an automatic welding device. The automatic welding device includes a rotary mechanism, a welding torch angle adjustment mechanism, and a lifting movement mechanism, and is used to weld the weld between a branch pipe and a main pipe. The branch pipe and the main pipe are arranged non-parallelly. The method includes the following steps:

[0007] Collect the existing weld image by using an image vision system, extract the weld edge contour, and draw the weld feature curve;

[0008] Construct a surface trajectory function and a welding torch angle adjustment function according to the weld feature curve, where the surface trajectory function includes a rotary motion function and a lifting motion function;

[0009] Make the welding torch angle adjustment mechanism, the rotary mechanism, and the lifting motion mechanism move according to the angle adjustment function, the rotary motion function, and the lifting motion function respectively.

[0010] In one or more embodiments, obtain a first intersection point between the main pipe cylinder surface and the weld feature curve, obtain a second intersection point between the branch pipe cylinder surface and the weld feature curve, and construct a lifting motion function and a welding torch angle adjustment function according to the first intersection point and the second intersection point.

[0011] In one or more embodiments, the independent variables of the surface trajectory function include time and the angular velocity of the rotary mechanism, and the dependent variables include the rotation angle of the rotary mechanism and the motion speed of the lifting motion mechanism.

[0012] In one or more embodiments, construct a function of the input current of the rotary mechanism and the angular velocity of the rotary mechanism.

[0013] In one or more embodiments, construct a function of the input current of the lifting motion mechanism and the motion speed of the lifting motion mechanism.

[0014] In one or more embodiments, adjust the angular velocity of the rotary mechanism to obtain the optimal rotation angle and the motion speed of the lifting motion mechanism.

[0015] In one or more embodiments, the independent variables of the welding torch angle adjustment function include time and the angular velocity of the change in the included angle between the branch pipe and the main pipe, and the dependent variable includes the angle of the welding torch relative to the branch pipe or the main pipe.

[0016] In one or more embodiments, construct a function of the input current of the welding torch angle adjustment mechanism and the angular velocity of the change in the included angle between the branch pipe and the main pipe.

[0017] In one or more embodiments, obtain the included angle between the branch pipe and the main pipe using the cosine value of the included angle between the cylindrical normal vector of the branch pipe and the cylindrical normal vector of the main pipe.

[0018] In one or more embodiments, use the first intersection point and the second intersection point to construct rsinθ0 = Rsinθ3, where r is the radius of the branch pipe, R is the radius of the main pipe, θ3 is the included angle between the first intersection point and the lifting direction, and θ0 is the included angle between the second intersection point and the axial direction of the main pipe.

[0019] In one or more embodiments, the cosine value of the included angle is cosθ4 = sinθ0sinθ3; substitute rsinθ0 = Rsinθ3 into the cosine value of the included angle to obtain Method for obtaining the included angle between the branch pipe and the main pipe Where r is the radius of the branch pipe, R is the radius of the main pipe, θ4 is the included angle between the branch pipe and the main pipe, and θ0 is the included angle between the second intersection point and the axial direction of the main pipe.

[0020] In one or more embodiments, the rotational motion function is a proportional function, and the lifting motion function and the angle adjustment function are waveform chord functions.

[0021] In one or more embodiments, the curved surface trajectory equation is Where the lifting motion function is The rotational motion function is θ = ω0t0, where θ0 is the included angle between the weld and the intersection point of the branch pipe relative to the axial direction of the main pipe, t0 is the time for the rotational mechanism to move around the branch pipe, ω0 is the angular velocity of the rotational mechanism, R is the radius of the main pipe, and r is the radius of the branch pipe.

[0022] In one or more embodiments, the angle adjustment function is Where A is the angle adjustment proportional coefficient, C is the angle adjustment constant, t0 is the time for the rotational mechanism to move around the branch pipe, and ω4 is the angular velocity of the change in the included angle between the branch pipe and the main pipe.

[0023] The above method realizes weld trajectory recognition and feature extraction through an image processing algorithm, and based on the weld trajectory data, uses a speed waveform to control and adjust the lifting trajectory and the angle of the welding torch. Instead of sequential displacement, it uses the lifting motion function as a one-dimensional speed waveform function and the rotational motion function as a two-dimensional trajectory speed waveform function, and realizes a three-dimensional welding trajectory through the superposition of one-dimensional and two-dimensional. By constructing a welding torch angle adjustment function, it controls the overall motion waveform curve of the automatic welding equipment to be smooth and continuous without inflection points, so that the movement of the welding torch is continuous without interruption, avoiding rigid and flexible impacts. Brief Description of the Drawings

[0024] The above and other features, properties, and advantages of the present invention will become more obvious through the following description in conjunction with the drawings and embodiments, where:

[0025] Figure 1 is a schematic diagram of collecting a weld trajectory by an image vision system;

[0026] Figure 2 is a schematic diagram of the welding structure of the main pipe and the branch pipe;

[0027] Figure 3 is a schematic diagram of the included angle between the main pipe and the branch pipe;

[0028] Figure 4A is a schematic diagram of the weld imaging plane;

[0029] Figure 4B is a schematic diagram when extracting the edge contour of the weld;

[0030] Figure 5 is a schematic diagram of a welding device;

[0031] Figure 6 is a schematic diagram of the cross-section of the main pipe;

[0032] Figure 7 is a schematic diagram of the cross-section of the branch pipe;

[0033] Figure 8 is a schematic diagram of the equality relationship between rsinθ0 and Rsinθ3;

[0034] Figure 9 is the waveform curve of the Z-axis movement speed function v z changing with time;

[0035] Figure 10 is the waveform curve of the Z-axis movement displacement function Z x changing with time;

[0036] Figure 11 is the waveform curve of the torch angle adjustment function θ1 changing with time at different angular velocities ω0 of the slewing mechanism;

[0037] Figure 12 is the waveform curve of the angle change function θ4 between the main pipe and the branch pipe changing with time at different angular velocities ω0 of the slewing mechanism;

[0038] Figure 13 is the waveform curve of the angular velocity change function ω4 of the angle between the main pipe and the branch pipe changing with time when the angular velocity ω0 of the slewing mechanism is 6;

[0039] Figure 14 is the waveform curve of the angular velocity change function ω4 of the angle between the main pipe and the branch pipe changing with time when the angular velocity ω0 of the slewing mechanism is 12;

[0040] Figure 15 is the waveform curve of the angular velocity change function ω4 of the angle between the main pipe and the branch pipe changing with time when the angular velocity ω0 of the slewing mechanism is 72;

[0041] Figure 16 is the waveform curve of the input current I of the Z-axis movement mechanism changing with time at different torque-to-voltage ratios z changing with time;

[0042] Figure 17 is the waveform curve of the input current I4 of the angle adjustment mechanism changing with time at different torque-to-voltage ratios. Specific implementation manners

[0043] The present invention will be further described below in conjunction with specific embodiments and the accompanying drawings. More details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention is obviously capable of being implemented in many other ways different from this description. Those skilled in the art can make similar generalizations and deductions according to the actual application situation without departing from the connotation of the present invention. Therefore, the protection scope of the present invention should not be limited by the content of this specific embodiment.

[0044] It should be noted that these and subsequent other drawings are only examples, and they are not drawn under the condition of equal proportions, and should not be used to limit the actual protection scope required by the present invention.

[0045] The present disclosure proposes a welding angle control method based on welding trajectory recognition, which splits a three-dimensional complex trajectory into a one-dimensional motion trajectory in the height direction of the lifting edge and a two-dimensional motion trajectory along the circumferential surface, and obtains a three-dimensional welding trajectory according to the linkage of the one-dimensional motion trajectory and the two-dimensional motion trajectory, thereby realizing continuous movement and angle adjustment of the welding torch.

[0046] This method is applicable to Figure 2 the welding process of the main pipe 100 and the branch pipe 200 shown in the figure. The branch pipe 200 is welded on the main pipe 100 to form a weld seam 300, and the branch pipe 200 is arranged non-parallel to the main pipe 100.

[0047] Figures 4A - 4B Further show pictures of the weld seam and processed images. According to Figure 1 , Figure 4A it can be seen that since the welding hole 5 for forming the main pipe 100 and the branch pipe 200 is an inclined plane, the relative angle θ4 between the main pipe 100 and the branch pipe 200 has different values along one circle of the weld seam. At the highest point P of the weld seam where the branch pipe 200 and the main pipe 100 meet, the relative angle θ4 between the main pipe 100 and the branch pipe 200 is 90°, and at the lowest point Q of the weld seam, the relative angle θ4 between the main pipe 100 and the branch pipe 200 is an acute angle, for example, 60°. The magnitude of the relative angle θ4 between the main pipe 100 and the branch pipe 200 at the lowest point Q of the weld seam depends on the pipe diameter sizes of the main pipe 100 and the branch pipe 200 respectively.

[0048] In the following drawings, the X-axis is used to represent the axial direction of the main pipe 100, and the Z-axis is used to represent the lifting direction, that is, the height direction, which is also the axial direction of the branch pipe 200 in the embodiment shown in Figure 2 the figure, and the Y-axis is orthogonally arranged with the X-axis and the Z-axis.

[0049] This method is used to adjust the movement of the automatic welding equipment, and then weld the weld seam between the branch pipe and the main pipe. Figure 5A simplified diagram of an automatic welding device is shown. The automatic welding device includes a rotary mechanism a, a welding torch angle adjustment mechanism b, and a lifting movement mechanism c. The rotary mechanism a drives the welding torch to rotate around the Z-axis. The welding torch angle adjustment mechanism b is used to adjust the angle between the welding torch and the main pipe and the branch pipe. The lifting movement mechanism c is used to adjust the height of the welding torch relative to the main pipe or the branch pipe.

[0050] In some embodiments, it further includes a left-right transverse movement mechanism d, which is used to adjust the distance between the welding torch and the branch pipe along the X-axis direction to prevent the welding torch from hitting the branch pipe.

[0051] The method includes the following steps: First, use an image vision system 60 to collect the weld image of the existing welded specimen, accurately segment the groove area, extract the edge contour, and draw the weld feature curve; construct a surface trajectory function and a lifting movement function according to the weld feature curve; make the welding torch angle adjustment mechanism b, the rotary mechanism a, and the lifting movement mechanism c move according to the angle adjustment function, the rotary movement function, and the lifting movement function respectively.

[0052] The weld feature curve 400 is shown in Figure 4. It can be understood that the weld feature curve 400 is not a planar curve, but a space curve with three-dimensional coordinates of X, Y, and Z.

[0053] Obtain the intersection points of the cylindrical surfaces of the branch pipe 200 and the main pipe 100 with the weld respectively. Figure 6 A schematic diagram of the first intersection point A formed by the cylindrical surface of the main pipe 100 and the weld feature curve 400 on the main pipe cross-section (Y-O-Z plane) is shown. Figure 7 A schematic diagram of the first intersection point B formed by the cylindrical surface of the branch pipe 200 and the weld feature curve 400 on the branch pipe cross-section (X-O-Y plane) is shown. Where, θ3 is the angle between the first intersection point A and the Z-axis, and θ0 is the angle between the second intersection point B and the X-axis. The branch pipe 200 has a radius r, and the main pipe 100 has a radius R.

[0054] The normal equation of the branch pipe cylindrical surface is L1: y = tanθ0x, and the normal equation of the main pipe cylindrical surface L2: z = cotθ3y. Define (x1, y1, z1) as the coordinates of the intersection point of the main pipe cylindrical surface normal L1 and the weld, that is, the coordinates of the first intersection point, and (x2, y2, z2) as the coordinates of the intersection point of the branch pipe cylindrical surface normal L2 and the weld, that is, the coordinates of the second intersection point. Then the intersection point coordinates respectively satisfy the following relationships:

[0055] (x1, y1, z1) = (0, Rsinθ3, Rcosθ3), (x2, y2, z2) = (rcosθ0, rsinθ0, 0).

[0056] Furthermore, it can be understood that for Figures 6 - 7 the projected curve shown, such as Figure 8As shown in the figure, the two included angles and the diameters satisfy the following relationship: $r\sin\theta_0 = R\sin\theta_3$, where $r\sin\theta_0$ is the displacement component of the welding torch on the y-axis of the branch pipe, and $R\sin\theta_3$ is the displacement component of the welding torch on the y-axis of the main pipe.

[0057] Referring back to Figure 4, to obtain the included angle $\theta_4$ between the branch pipe and the main pipe, it is through the cosine value of the included angle between the normal vector of the branch pipe cylinder surface and the normal vector of the main pipe cylinder surface. For example, if the normal vector of the main pipe cylinder surface is The normal vector of the branch pipe cylinder surface is The cosine value of the included angle between the two normal vectors is

[0058] According to the normal equation of the branch pipe cylinder surface $L_1: y = \tan\theta_0x$ and the normal equation of the main pipe cylinder surface $L_2: z = \cot\theta_3y$, substituting $(0, R\sin\theta_3, R\cos\theta_3)$ and $(r\cos\theta_0, R\sin\theta_0, 0)$ into the equations:

[0059]

[0060] And according to the relationship $r\sin\theta_0 = R\sin\theta_3$ at this time, we can get Furthermore, the method for obtaining the included angle between the branch pipe and the main pipe

[0061] According to the above geometric relationships, the data of the first intersection point and the second intersection point, construct the surface trajectory function and the welding torch angle adjustment function.

[0062] I. Provide the surface trajectory function

[0063] The surface trajectory function includes two parts: the rotary motion function and the lifting motion function. Since the weld connecting the main and branch pipes is equivalent to a circular motion and a vertical motion, to achieve this trajectory requires the combination of circular motion and lifting motion. Therefore, the rotary motion function of the surface trajectory function is used for circular motion, and the lifting motion function is used to achieve the lifting motion.

[0064] The independent variables of the surface trajectory function include time $t$ and the angular velocity $\omega_0$ of the rotary mechanism, and the dependent variables include the rotation angle $\theta$ of the rotary mechanism and the motion speed function $v$ of the lifting motion mechanism z :

[0065] The surface trajectory implementation equation is $t_0$ is the time for the rotary mechanism to rotate around the branch pipe, and $z$ x is the displacement function of the z-axis motion. Within $0\leq\theta\leq360^{\circ}$, the rotary mechanism rotates around the branch pipe in a circular motion.

[0066] The equation for realizing the curved surface trajectory includes a proportional function and a waveform chord function. The proportional function can achieve circular motion within 0 - 360° according to the change of time, and the waveform function enables the lifting mechanism to achieve speed change according to a preset function according to the change of time.

[0067] It can be understood that the first part of the equation for realizing the curved surface trajectory, that is, the rotation angle θ of the rotary mechanism around the central axis of the branch pipe, can be represented by the angle θ0 of the intersection point of the weld seam and the branch pipe relative to the X-axis, that is, θ = θ0 = ω0t0, which is the speed waveform of the two-dimensional trajectory (circle).

[0068] Another part of the equation for realizing the curved surface trajectory, that is, the z-axis movement speed function of the lifting mechanism, is first obtained from the z-axis movement displacement function z x obtained. According to the appendix Figure 8 , Combined with θ0 = ω0t0, obtain Differentiate the z-axis movement displacement function to obtain which is the speed waveform curve of the one-dimensional trajectory (axis).

[0069] Thus, the equation of the curved surface trajectory is The equation of the curved surface trajectory realizes the three-dimensional welding trajectory by controlling the welding mechanism according to the speed waveforms of the one-dimensional and two-dimensional trajectories instead of sequential displacements. The waveform curve is smooth and continuous without inflection points, and the movement is continuous without interruption, so that there is no rigid and flexible impact during the welding process.

[0070] II. Provide the function for adjusting the welding torch angle

[0071] The function for adjusting the welding torch angle is a waveform function. According to the change of time, the welding torch angle adjustment mechanism can achieve the angle change of the welding torch according to a preset function.

[0072] Define the function for adjusting the welding torch angle as where θ1 is the function for adjusting the welding torch angle, and f(θ4) is the function for the change of the included angle between the branch pipe and the main pipe. The welding torch is located between the branch pipe and the main pipe during welding. If the welding torch is placed in the middle of the branch pipe and the main pipe, the welding torch angle is: θ1 = f(θ4) = 0.5θ4. If it is offset 1 degree upward or downward from the middle, the welding torch angle θ1 is 0.5θ4 ± 1°. A is the angle adjustment proportional coefficient, C is the angle adjustment constant, and t1 is any time. Since it is impossible to perfectly fit the function curve in actual welding, it is necessary to adjust through the two parameters A and C, and manually set the welding angle that meets the requirements according to the needs and welding conditions during the actual welding process. ω4 is the differential of the angle with respect to time, that is, the function of the angular velocity of the change of the included angle between the branch pipe and the main pipe.

[0073] Since Differentiating the included angle θ4 between the branch pipe and the main pipe with respect to time t0 gives the angular velocity ω4 of the change of the included angle between the branch pipe and the main pipe:

[0074]

[0075] Based on this, an angle adjustment function is obtained. Where the angular velocity ω4 of the change in the included angle of the header pipe is as described in the above formula and is a kind of velocity wave function. The welding torch angle adjustment mechanism moves according to the angle adjustment function to adjust the angle of the welding torch during the welding process.

[0076] This angle adjustment function solves the relational expression between the change in the welding torch angle and the velocity of the two-dimensional trajectory movement by establishing a mathematical model and according to geometric relationships. By controlling the velocity waveform, the change in the welding torch angle is directly controlled, and the angle change is continuous without inflection points and is relatively smooth.

[0077] III. Obtaining the current functions of the welding torch angle adjustment mechanism, the slewing mechanism, and the lifting motion mechanism

[0078] The welding torch angle adjustment mechanism, the slewing mechanism, and the lifting motion mechanism can achieve motion according to the preset current functions.

[0079] For the slewing mechanism, the current function enables the slewing mechanism to achieve angular velocity change according to the preset current function, and its expression is I1 = f(ω0), which is a kind of waveform function, where I1 is the input current of the slewing mechanism; f(ω0) is a function of the angular velocity ω0.

[0080] Furthermore, Where U0 is the voltage, F0 is the torque, and v1 is the linear velocity of the slewing mechanism.

[0081] For the lifting motion mechanism, the current function enables the lifting motion mechanism to achieve lifting change according to the preset current function. The z-axis motion mechanism can achieve velocity change according to the preset current function, expressed as I z = f(v z ), where I z is the input current of the z-axis motion mechanism, and f(v z ) is a function of v z . According to P = UI = Fv, we get After arrangement, we get I z = f(v z ), F0 is the torque, and v z is the velocity of the lifting motion mechanism.

[0082] For the welding torch angle adjustment mechanism, the relational equation between the current and the welding torch adjustment angular velocity is I4 = f(ω4). According to P = UI = Fv, we get After arrangement, we get I4 = f(ω4).

[0083] Through the above input current function, this method can not only achieve welding trajectory and torch angle adjustment through speed control, but also through current control. Specifically, by giving current control functions for different objects controlling the movement of the torch, and controlling the speed function through the current function, it can achieve the movement of a specific curved surface trajectory required for the weld seam and a specific torch angle.

[0084] When R is 10 mm, r is 5 mm, and the angular velocities of the slewing mechanism are 6, 12, and 72 respectively, the z-axis speed waveform curves of the lifting mechanism are as Figure 9 shown, the z-axis displacement waveform curves of the lifting mechanism are as Figure 10 shown, the torch angle waveform curves are as Figure 11 shown, the waveform curves of the angle change between the branch pipe and the main pipe are as Figure 12 shown, and the torch angular velocity waveform curves are as shown in the appendix Figures 13 - 15 shown.

[0085] When is 1, 5, and 10 respectively, the current waveform curves of I z = f(v z ) and the current waveform curves of I4 = f(ω4) are as shown in the appendix Figure 16 and the appendix Figure 17 shown.

[0086] When ω0 = 6, A = 3, C = π, and t0 changes, the values of other parameters are shown in Table 1:

[0087] Table 1 Variation values of each parameter with time

[0088] <![CDATA[Exercise time / t0 (s)]]> 0 10 15 <![CDATA[Rotation angle / θ0 (rad)]]> 0 π / 3 0.5π <![CDATA[Welding torch angle / θ1 (rad)]]> 2π 2.13293π 2.5π <![CDATA[Angle between the branch pipe and the main pipe / θ4 (rad)]]> 0.5π 0.37764π π / 3 <![CDATA[Z-axis displacement / z x (mm)]]> 10 9.88318 8.84535 <![CDATA[Z-axis moving speed / v1 (mm / s)]]> -3 2.89101 1.5027 <![CDATA[Angular velocity of the welding torch / ω4 (° / s)]]> 0 -1.74372 2.62191

[0089] The above method has the following advantages:

[0090] (1) Through the image processing algorithm, the weld seam trajectory recognition and feature extraction are realized. Based on the weld seam trajectory data, the lifting trajectory and torch angle are adjusted using the speed waveform control. Instead of sequential displacement, the lifting motion function is used as a one-dimensional speed waveform function, and the slewing motion function is used as a two-dimensional trajectory speed waveform function. The three-dimensional welding is realized through the linkage of one-dimensional and two-dimensional, and by constructing the torch angle adjustment function, the overall motion waveform curve of the automatic welding equipment is controlled to be smooth and continuous without inflection points, so that the torch movement is continuous without interruption, avoiding rigid and flexible impacts.

[0091] (2) By giving current control functions for different objects controlling the movement of the torch, and controlling the speed function through the current function, it can achieve the movement of a specific curved surface trajectory required for the weld seam and a specific torch angle;

[0092] (3) This method establishes the relationship between the trajectory equation, the adjustment of the welding torch angle, angular velocity, and time. As long as the angular velocity or time is controlled, that is, as long as one parameter is controlled, complex welding trajectories and the adjustment of the welding torch angle can be achieved simultaneously.

[0093] This application uses specific terms to describe the embodiments of this application. For example, "one embodiment", "an embodiment", and / or "some embodiments" mean a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that "an embodiment" or "one embodiment" or "an alternative embodiment" mentioned twice or more at different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application can be appropriately combined.

[0094] Although the present invention is disclosed above in preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modifications, equivalent changes, and decorations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention all fall within the protection scope defined by the claims of the present invention.

Claims

1. An automatic welding control method for adjusting the movement of an automatic welding device, the automatic welding device comprising a rotation mechanism, a welding gun angle adjustment mechanism and a lifting mechanism, for welding a weld between a branch pipe and a main pipe, the branch pipe being arranged non-parallel to the main pipe, characterized in that: The method comprises the following steps: Use image vision system to collect existing weld images, extract weld edge contours, and draw weld characteristic curves; Constructing a surface trajectory function and a welding gun angle adjustment function according to the weld characteristic curve, wherein the surface trajectory function includes a rotation motion function and a lifting motion function; The welding gun angle adjustment mechanism, the rotary mechanism and the lifting and lowering motion mechanism are respectively moved according to the angle adjustment function, the rotary motion function and the lifting and lowering motion function.

2. The automatic welding control method according to claim 1, characterized in that: A first intersection point between the main pipe cylinder and the weld characteristic curve is obtained, a second intersection point between the branch pipe cylinder and the weld characteristic curve is obtained, and a lifting motion function and a welding gun angle adjustment function are constructed according to the first intersection point and the second intersection point.

3. The automatic welding control method according to claim 1, characterized in that: The independent variables of the curved surface trajectory function include time and the angular velocity of the rotary mechanism, and the dependent variables include the rotary angle of the rotary mechanism and the movement speed of the lifting mechanism.

4. The automatic welding control method according to claim 3, characterized in that: Construct the function of the input current of the rotary mechanism and the angular velocity of the rotary mechanism.

5. The automatic welding control method according to claim 3, characterized in that: Construct a function of the input current of the lifting motion mechanism and the movement speed of the lifting motion mechanism.

6. The automatic welding control method according to claim 3, characterized in that: The angular velocity of the rotary mechanism is adjusted to obtain the optimal rotary angle and the movement speed of the lifting movement mechanism.

7. The automatic welding control method according to claim 1, characterized in that: The independent variables of the welding gun angle adjustment function include time and the angular velocity of the angle change between the branch pipe and the main pipe, and the dependent variable includes the angle of the welding gun relative to the branch pipe or the main pipe.

8. The automatic welding control method according to claim 7, characterized in that: Construct the function of the input current of the welding gun angle adjustment mechanism and the angular velocity of the angle between the branch pipe and the main pipe.

9. The automatic welding control method according to claim 2, characterized in that: The angle between the branch pipe and the main pipe is obtained by using the cosine value of the angle between the cylinder normal vector of the branch pipe and the cylinder normal vector of the main pipe.

10. The automatic welding control method according to claim 9, characterized in that: Using the first intersection point and the second intersection point, rsinθ0=Rsinθ3 is constructed, where r is the branch pipe radius, R is the main pipe radius, θ3 is the angle between the first intersection point and the lifting direction, and θ0 is the angle between the second intersection point and the axial direction of the main pipe.

11. The automatic welding control method according to claim 10, characterized in that: The cosine value of the angle is cosθ4=sinθ0sinθ3; Substitute rsinθ0=Rsinθ3 into the cosine value of the angle and obtain How to find the angle between the branch pipe and the main pipe Where r is the radius of the branch pipe, R is the radius of the main pipe, θ4 is the angle between the branch pipe and the main pipe, and θ0 is the angle between the second intersection point and the axial direction of the main pipe.

12. The automatic welding control method according to claim 1, characterized in that: The rotational motion function is a proportional function, and the lifting motion function and the angle adjustment function are waveform chord functions.

13. The automatic welding control method according to claim 12, characterized in that: The surface trajectory equation is The lifting motion function is The rotational motion function is θ=ω0t0, θ0 is the angle between the intersection of the weld and the branch pipe relative to the axial direction of the main pipe, t0 is the time for the rotation mechanism to move around the branch pipe, ω0 is the angular velocity of the rotation mechanism, R is the radius of the main pipe, and r is the radius of the branch pipe.

14. The automatic welding control method according to claim 12, characterized in that: The angle adjustment function is: Where A is the angle adjustment proportional coefficient, C is the angle adjustment constant, t0 is the time for the rotary mechanism to move around the branch pipe, and ω4 is the angular velocity of the angle change between the branch pipe and the main pipe.

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