Multi-layer multi-pass path planning method for space girth welds

Abstract

The application discloses a kind of multilayer multi-pass path planning methods for space annular weld, the method includes obtaining weld feature points;Obtain the characteristic data of weld section;Confirm the spatial position of each weld subsection by weld feature points, to obtain the weld subsection data of annular weld;Obtain the arc degree of each weld subsection, and based on the preset welding starting point and welding torch initial attitude, obtain the location of breakpoint section at weld subsection and the welding torch attitude at corresponding breakpoint section;According to the characteristic data, obtain the weld bead characteristic data of each layer welding weld bead;According to the welding weld bead of corresponding layer in each weld subsection as the same level weld bead layer in annular weld, to obtain the multilayer multi-pass path of annular weld;And through preset non-welding path and multilayer multi-pass path, realize the multilayer multi-pass path planning of space annular weld.The application solves the problem of low welding efficiency and insufficient precision existing in the prior art welding method of space annular weld.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of welding, in particular to a multi-layer multi-pass path planning method for a space annular weld. BACKGROUND

[0002] In shipbuilding, there are significant difficulties in pipe system welding. After pipe system assembly, the shape is complex, the pipe diameter is from 10mm to 600mm, and the shape is complex such as spiral, Z-shaped, U-shaped, etc. The design of welding bevel of different pipe diameters, the filling amount, and the welding requirements of multi-layer and multi-pass are quite different.

[0003] Usually, such pipe system welding adopts full position welding equipment or manual welding: however, manual welding has flexibility, but has low efficiency, and the parameter adjustment relies on the experience of on-site engineers, is affected by the difference in welding technology, and the welding quality is inconsistent. The full position welding equipment can cover flat, vertical, horizontal and overhead full position welds, but the molten pool shape of different positions is greatly different due to gravity, and the welding parameters need to be adjusted on site to ensure the formation of the weld, which is not universal. SUMMARY

[0004] The present application provides a multi-layer multi-pass path planning method for a space annular weld to overcome the above technical problems.

[0005] In order to achieve the above purpose, the technical scheme of the present application is:

[0006] A multi-layer multi-pass path planning method for a space annular weld, specifically comprising the following steps:

[0007] S1: obtaining the weld characteristic points of the weld section of the V-shaped butt weld through the preset laser system; and the weld characteristic points are the contour characteristic points of the weld section of the V-shaped butt weld;

[0008] S2: obtaining the characteristic data of the weld section according to the weld characteristic points; and the characteristic data includes the bottom width, the top width and the section height of the weld section;

[0009] S3: randomly dividing the annular weld into several weld segments;

[0010] and confirming the weld space position of each weld segment through the weld characteristic points, obtaining the segment data of the annular weld according to the weld space position; and the segment data at least includes the center point coordinates and the circular arc plane normal vector;

[0011] S4: obtaining the circular arc degree of each weld segment, i.e. the radian value of the segment circular arc, and based on the preset welding starting point and the initial attitude of the welding torch, obtaining the position of the breakpoint section of the weld segment and the attitude of the welding torch at the corresponding breakpoint section;

[0012] S5: randomly divide each weld segment into several layers of weld beads with same number of layers and different thickness or same thickness, and acquire weld bead characteristic data of each layer of weld bead according to the characteristic data;

[0013] and the weld bead characteristic data at least includes weld bead starting point, weld bead ending point and weld bead thickness;

[0014] S6: take the weld bead of the corresponding layer in each weld segment as the same level weld bead layer in the annular weld, to acquire the multi-layer and multi-pass path of the annular weld;

[0015] S7: preset a non-welding transition path for switching between different levels of weld bead; and realize the multi-layer and multi-pass path planning of the spatial annular weld through the combination of the non-welding transition path and the multi-layer and multi-pass path.

[0016] Further, the S3 specifically includes the following steps:

[0017] S31: randomly divide the annular weld into n weld segments; wherein the annular weld includes n+1 break points of initial section and terminal section;

[0018] confirm the weld space position of each weld segment through the weld characteristic points, and set the weld space position points A, B, C on the annular weld arc in each weld segment;

[0019] S32: acquire the weld segment data of the annular weld according to the weld space position points; and the weld segment data at least includes the center point coordinates O and the arc plane normal vector e;

[0020] The solving equation group of the center point coordinates is:

[0021] ,

[0022] ,

[0023] ,

[0024] In the formula, U represents the middle point of the line connecting the weld space position point A and the weld space position point B; V represents the middle point of the line connecting the weld space position point B and the weld space position point C; , , , , , , all represent direction vectors; · represents the vector dot product operator symbol; x represents the vector cross product operator symbol;

[0025] The expression of the arc plane normal vector e is

[0026] .

[0027] Further, the S4 specifically includes the following steps:

[0028] S41: Obtain the circular arc degree θ of each weld segment, and obtain the rotation matrix Q according to the normal vector e of the circular arc plane, and the formula for obtaining the rotation matrix Q is

[0029] ,

[0030] ,

[0031] In the formula: I represents a 3x3 unit matrix; E represents the skew-symmetric matrix of the normal vector e of the circular arc plane; e1, e2, e3 represent the spatial vector components of the normal vector e of the circular arc plane;

[0032] S42: Based on the preset welding starting point and the initial pose of the welding torch, the position of the breakpoint section at the weld segment and the pose of the welding torch at the corresponding breakpoint section are obtained according to the rotation matrix Q;

[0033] The formula for obtaining the position of the breakpoint section at the weld segment is

[0034] ,

[0035] In the formula: represents the position of the breakpoint section at the weld segment; represents the preset welding starting point;

[0036] The formula for obtaining the pose of the welding torch at the corresponding breakpoint section is

[0037] ,

[0038] In the formula: represents the pose of the welding torch at the corresponding breakpoint section; represents the initial pose of the welding torch.

[0039] Further, the S5 specifically includes the following steps:

[0040] S51: Define that each weld segment includes a plurality of layers of multi-welding passes, define the welding segment k as the middle segment of the breakpoint section k and the breakpoint section k+1, and define the pass starting point and the pass ending point of the first layer of welding passes in the welding segment k as ;

[0041] S52: According to the cross-section height of the weld cross-section, confirm the lifting height of the welding torch for the first layer of welding passes;

[0042] and the lifting height of the welding torch for the first The expression for the welding torch lift height of a layer weld bead is:

[0043] ,

[0044] In the formula: Indicates the first The height at which the welding torch is raised during layer welding; Indicates the first [section height] defined by the [section height]. The thickness of the weld bead in the layer welding;

[0045] S53: Obtain the coordinates of the center point O to the location of the section at the breakpoint k. Direction vector And the direction vector The formula for obtaining it is

[0046] ,

[0047] And according to the direction vector Obtain the extended vector OB, and the formula for obtaining the extended vector OB is:

[0048] ,

[0049] S54: Based on the center point coordinates O and the extended vector OB, obtain the first... The start point of a layered weld bead is expressed as follows:

[0050] ,

[0051] Based on the coordinates of the center point O and the first The welding torch height for each layer of welding is adjusted to obtain the first layer. The end point of a layered weld bead is expressed as follows:

[0052] .

[0053] Furthermore, it also includes using Z-shaped oscillating welding for each layer of welding passes in the multi-layer, multi-pass path of the circumferential weld.

[0054] Furthermore, the oscillation amplitude of the Z-shaped oscillation welding using the welding torch is the weld width, and the formula for calculating the weld width is:

[0055] ,

[0056] In the formula: Indicates the first The width of the weld bead in a layered weld; Indicates the top width; This represents the base angle of an isosceles trapezoid formed by its bottom width, top width, and cross-sectional height.

[0057] Beneficial effects: the present application provides a multi-layer multi-pass path planning method for a space annular weld, in the full-position welding process of the space annular weld, the space annular weld is divided into different welding segments of multi-layer welding passes, and the welding passes of the corresponding layer in each weld segment are taken as the same level pass layer in the annular weld to obtain the multi-layer multi-pass path of the entire space annular weld; at the same time, the pass feature data of each layer welding pass is calculated for different welding segments; and the pass feature data at least includes the pass start point, the pass end point and the pass thickness, without adjusting the welding parameters on site to ensure the weld forming, the welding precision and efficiency of the space annular weld are greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0058] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0059] Figure 1 A flowchart of the multi-layer multi-pass path planning method for a space annular weld of the present application;

[0060] Figure 2 A schematic diagram of the weld cross section of the V-type butt weld in the present embodiment;

[0061] Figure 3 A schematic diagram of the multi-layer multi-pass path of the space annular weld in the present embodiment. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the following will combine the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0063] The present embodiment provides a multi-layer multi-pass path planning method for a space annular weld, specifically including the following steps:

[0064] S1: obtaining the weld feature points of the weld cross section of the V-type butt weld through the preset laser system; and the weld feature points are the contour feature points of the weld cross section of the V-type butt weld;

[0065] Specifically, the preset laser system in the embodiment includes a laser sensor and a laser controller, and the laser system is installed on a robot body configured with a robot control system, the robot control system is in communication connection with a welding system through a Mod bus TCP bus, the welding system is a known technology and includes a welding power source, a cooling water tank, a wire feeder, a welding torch, and the like; the laser system, the robot control system, and the preset host computer are all in communication connection through a TCP network. In the embodiment, the collaborative robot is used to execute a welding motion track and control the welding system; the laser system is used for weld seam identification, wherein the method of the laser system for weld seam identification in the embodiment is a known technology, which will not be described in detail here; the welding system is used to execute a welding process; the host computer control system is used for human-computer interaction and multi-layer multi-pass welding program generation; wherein, the method of realizing human-computer interaction and multi-layer multi-pass welding program generation through the preset host computer control system in the embodiment is a known technology, which will not be described in detail here.

[0066] S2: acquiring feature data of the weld seam section according to the weld seam feature points; and the feature data includes a bottom width, a top width, and a section height of the weld seam section; wherein the shape of the weld seam section in the embodiment is specifically an isosceles trapezoid;

[0067] S3: randomly dividing the girth weld into a plurality of weld segments;

[0068] and confirming the weld seam spatial position of each weld segment through the weld seam feature points, acquiring segment data of the girth weld according to the weld seam spatial position; and the segment data at least includes a center point coordinate and a circular arc plane normal vector; specifically including the following steps:

[0069] S31: randomly dividing the girth weld into n weld segments; wherein the girth weld includes n+1 breakpoint sections of initial sections and terminal sections;

[0070] confirming the weld seam spatial position of each weld segment through the weld seam feature points, and setting the weld seam spatial position points A, B, C on the circular arc of the girth weld in each weld segment;

[0071] S32: acquiring weld segment data of the girth weld according to the weld seam spatial position points; and the weld segment data at least includes a center point coordinate O and a circular arc plane normal vector e;

[0072] The solving equation group of the center point coordinate is:

[0073] ,

[0074] ,

[0075] ,

[0076] In the formula, U represents a middle point of a line connecting the weld seam spatial position point A and the weld seam spatial position point B; V represents a middle point of a line connecting the weld seam spatial position point B and the weld seam spatial position point C; all represent direction vectors; · represents a vector dot product operator symbol; and × represents a vector cross product operator symbol;

[0077] An expression of the circular arc plane normal vector e is

[0078]

[0079] S4: Obtain the circular arc degree of each weld seam segment, that is, the radian value of the segmented circular arc, and obtain the position of a breakpoint section at the weld seam segment and a welding gun attitude at the corresponding breakpoint section based on a preset welding starting point and an initial welding gun attitude; specifically including the following steps:

[0080] S41: Obtain the circular arc degree θ of each weld seam segment, and obtain a rotation matrix Q according to the circular arc plane normal vector e, and the obtaining formula of the rotation matrix Q is

[0081]

[0082]

[0083] In the formula, I represents a 3*3 unit matrix; E represents a skew-symmetric matrix of the circular arc plane normal vector e; e1, e2, and e3 represent spatial vector components of the circular arc plane normal vector e;

[0084] S42: Obtain the position of the breakpoint section at the weld seam segment and the welding gun attitude at the corresponding breakpoint section according to the rotation matrix Q based on the preset welding starting point and the initial welding gun attitude;

[0085] The obtaining formula of the position of the breakpoint section at the weld seam segment is

[0086]

[0087] In the formula, represents the position of the breakpoint section at the weld seam segment; represents the preset welding starting point;

[0088] The obtaining formula of the welding gun attitude at the corresponding breakpoint section is

[0089] ​​​​​​​​​​​

[0090] wherein: represents the welding gun pose at the corresponding breakpoint section; represents the initial pose of the welding gun;

[0091] S5: randomly dividing each weld segment into a plurality of layer welding beads with the same number of layers and different thicknesses or the same thickness, and acquiring the bead feature data of each layer welding bead according to the feature data;

[0092] and the bead feature data at least includes the bead starting point, the bead ending point, and the bead thickness;

[0093] Specifically comprising the following steps:

[0094] S51: defining that each weld segment includes a plurality of layer welding beads, defining the welding segment k as the middle segment between the breakpoint section k and the breakpoint section k+1, and defining the bead starting point and the bead ending point of the first layer welding bead in the welding segment k as ;

[0095] S52: according to the section height of the weld section, confirming the welding gun lifting height of the first layer welding bead;

[0096] and the expression of the welding gun lifting height of the first layer welding bead is

[0097] ,

[0098] wherein: represents the welding gun lifting height of the first layer welding bead; represents the thickness of the first layer welding bead defined according to the section height; S53: acquiring the direction vector from the center point coordinate O to the section position of the breakpoint section k;

[0099] and the acquisition formula of the direction vector is

[0100] ,

[0101] and acquiring the extension vector OB according to the direction vector , and the acquisition formula of the extension vector OB is

[0102] ,

[0103] S54: acquiring the bead starting point of the first layer welding bead according to the center point coordinate O and the extension vector OB, and the expression is ​​​​​​

[0104] ,

[0105] Based on the coordinates of the center point O and the first The welding torch height for each layer of welding is adjusted to obtain the first layer. The end point of a layered weld bead is expressed as follows:

[0106]

[0107] S6: The corresponding weld beads in each weld segment are taken as the same level weld bead layer in the circumferential weld to obtain a multi-layer, multi-pass path for the circumferential weld. In this embodiment, in order to segment the weld path and plan the multi-layer, multi-pass welding path, the weld is considered to be a spatial circumferential weld. Based on the position of the breakpoint section of the weld segment and the welding torch posture, the multi-layer weld bead distribution of each weld segment is obtained, and finally the welding trajectory path of the entire spatial circumferential weld is obtained. In this embodiment, the welding beads in each layer of the multi-layer, multi-pass path of the circumferential weld are also welded using Z-shaped oscillating welding.

[0108] Furthermore, the oscillation amplitude of the Z-shaped oscillation welding using the welding torch is the weld width, and the formula for calculating the weld width is:

[0109] ,

[0110] In the formula: Indicates the first The width of the weld bead in a layered weld; Indicates the top width; This represents the base angle of an isosceles trapezoid formed by its bottom width, top width, and cross-sectional height, specifically as follows: Figure 2 As shown, let: a be the upper base of the trapezoid, which is composed of feature point 1 and feature point 2, and its length can be obtained; b be the lower base of the trapezoid, which is composed of feature point 4 and feature point 6, and its length can be obtained. It is the base angle of the trapezoid, formed by feature point 2, feature point 1, and feature point 4. It can be derived from the values ​​of a, b, and H based on the known formula for calculating the angle of an isosceles trapezoid. The value of H is the height of the trapezoid, which can be obtained from feature point 3 and feature point 6. In this embodiment, the selection of Z-type oscillating welding process parameters based on the weld width and weld thickness is a well-known technical content, and will not be elaborated on here.

[0111] S7: preset a non-welding transition path for switching between different levels of welding beads; and realize the multi-layer multi-pass path planning of the space annular weld through the combination of the non-welding transition path and the multi-layer multi-pass path. In the embodiment, all layer welding beads can use the same transition point or multiple transition points, and the transition path is set according to the welding scene setting. The purpose of setting the transition path is to avoid the accumulation of welding heat caused by changing the welding bead in place, which causes the welding deformation of the welding bead. For the multi-layer multi-pass welding of the space annular weld, the welding position such as flat welding, vertical welding, horizontal welding, and overhead welding can be subdivided according to the welding position, and different preset welding process parameters are used to perform the welding work.

[0112] The method has the following beneficial effects: by dividing the multi-layer welding beads of different welding segments of the space annular weld during the all-position welding of the space annular weld, and taking the welding beads of the corresponding layers in each welding segment as the same level of bead layer in the annular weld to obtain the multi-layer multi-pass path of the entire space annular weld, the welding bead characteristic data of each layer of the welding bead is calculated for different welding segments; the welding bead characteristic data at least includes the welding bead starting point, the welding bead ending point, and the welding bead thickness, and the Z-type weaving welding is used based on the welding width to realize the welding of the space annular weld, without the need for adjusting the welding parameters on site to ensure the weld forming, which greatly improves the welding precision and efficiency of the space annular weld.

[0113] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A multi-layer, multi-pass path planning method for spatial circumferential welds, characterized in that, Specifically, the following steps are included: S1: The weld feature points of the V-shaped butt weld cross section are obtained by a preset laser system; and the weld feature points are the contour feature points of the V-shaped butt weld cross section. S2: Obtain the feature data of the weld section based on the weld feature points; and the feature data includes the bottom width, top width and section height of the weld section; S3: Randomly divide the circumferential weld into several weld segments; The spatial position of each weld segment is confirmed by the weld feature points, and the segment data of the circumferential weld is obtained based on the weld spatial position; and the segment data includes at least the center point coordinates and the arc plane normal vector. S4: Obtain the arc value of each weld segment, and based on the preset welding start point and welding torch initial posture, obtain the location of the break point section at the weld segment and the welding torch posture at the corresponding break point section. Specific steps include: S41: Obtain the radius θ of each weld segment, and obtain the rotation matrix Q based on the arc plane normal vector e. The formula for obtaining the rotation matrix Q is as follows: In the formula: I represents a 3x3 identity matrix; E represents the oblique symmetric matrix of the arc plane normal vector e; e1, e2, e3 represent the spatial vector components of the arc plane normal vector e. S42: Based on the preset welding start point and welding torch initial posture, obtain the location of the break point section at the weld segment and the welding torch posture at the corresponding break point section according to the rotation matrix Q. The formula for determining the location of the fracture section at the weld segment is as follows: In the formula: This indicates the location of the section where the weld segment breaks; Indicates the preset welding start point; The formula for obtaining the welding torch posture at the corresponding breakpoint section is as follows: In the formula: This indicates the welding torch posture at the corresponding breakpoint section. Indicates the initial position of the welding torch; S5: Divide each weld segment into several layers of weld beads with the same number of layers and different or the same thickness, and obtain the weld bead characteristic data of each layer of weld beads based on the characteristic data. Furthermore, the weld bead characteristic data includes at least the weld bead start point, weld bead end point, and weld bead thickness; S6: Take the corresponding weld bead layers in each weld segment as the same level weld bead layer in the circumferential weld to obtain a multi-layer, multi-pass path for the circumferential weld. S7: A non-welding transition path is preset for switching between different weld layers; and multi-layer multi-path planning of spatial annular welds is realized by combining the non-welding transition path with multi-layer multi-pass paths.

2. The multi-layer, multi-path planning method for spatial circumferential welds according to claim 1, characterized in that, S3 specifically includes the following steps: S31: The circumferential weld is randomly divided into n weld segments; the circumferential weld includes an initial section and a final section, totaling n+1 breakpoint sections; The spatial position of the weld in each weld segment is determined by the weld feature points, and the spatial position points of the weld on the arc of the circumferential weld in each weld segment are set as A, B, and C. S32: Obtain weld segment data of the annular weld based on the spatial location points of the weld; and the weld segment data includes at least the center point coordinates O and the arc plane normal vector e; The system of equations for solving the coordinates of the center point is as follows: In the formula: U represents the midpoint of the line connecting the spatial location point A of the weld and the spatial location point B of the weld; V represents the midpoint of the line connecting the spatial location point B of the weld and the spatial location point C of the weld. , , , , , , Both represent direction vectors; ˙ represents the vector dot product operator; × represents the vector cross product operator; The expression for the normal vector e of the circular arc plane is: 。 3. The multi-layer, multi-path planning method for spatial circumferential welds according to claim 2, characterized in that, S5 specifically includes the following steps: S51: Define each weld segment as comprising several layers of multiple weld passes, and define weld segment k as the intermediate segment between the breakpoint section k and the breakpoint section k+1. The weld segment k is defined as the segment containing the first weld pass. The start and end points of a layered weld bead are defined as follows: ; S52: Based on the cross-sectional height of the weld section, confirm the first... The height at which the welding torch is raised during layer welding; And the The expression for the welding torch lift height of a layer weld bead is: In the formula: Indicates the first The height at which the welding torch is raised during layer welding; Indicates the first [section height] defined by the [section height]. The thickness of the weld bead in the layer welding; S53: Obtain the coordinates of the center point O to the location of the section at the breakpoint k. Direction vector And the direction vector The formula for obtaining it is And according to the direction vector Obtain the extended vector OB, and the formula for obtaining the extended vector OB is: S54: Based on the center point coordinates O and the extended vector OB, obtain the first... The start point of a layered weld bead is expressed as follows: Based on the coordinates of the center point O and the first The welding torch height for each layer of welding is adjusted to obtain the first layer. The end point of a layered weld bead is expressed as follows: 。 4. The multi-layer, multi-path planning method for spatial circumferential welds according to claim 3, characterized in that, It also includes Z-shaped oscillating welding for each layer of welding pass in the multi-layer, multi-pass path of the circumferential weld; Furthermore, the oscillation amplitude of the Z-shaped oscillation welding using the welding torch is the weld width, and the formula for calculating the weld width is: In the formula: Indicates the first The width of the weld bead in a layered weld; Indicates the top width; This represents the base angle of an isosceles trapezoid formed by its bottom width, top width, and cross-sectional height. H It is the height of a trapezoid.

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