Skip line generation method based on profile steel laser cutting contour geometric information

Abstract

The invention discloses a jump line generation method based on section steel laser cutting contour geometric information, which comprises the following steps of: extracting starting and ending points corresponding to the geometric information based on the given geometric information, then obtaining coordinates on a circumcircle in a corresponding normal vector direction, and then generating a corresponding three-dimensional space jump line; meanwhile, the discrete point coordinates of the jump lines are correspondingly calculated, and the direction vectors of the discrete points are generated through arc discrete interpolation. According to the method, the middle point can be introduced for a special scene, it is guaranteed that the machining path meets the actual scene requirement, for example, the path needs to be located on the upper portion all the time, the middle point can be arranged on the upper portion, and collision and interference are avoided.

Description

Technical Field

[0001] The invention relates to the technical field of laser cutting, and in particular to a method for generating a jump line based on geometric information of a profiled steel laser cutting contour. Background Art

[0002] There are many types of steel, including steel pipes, steel plates, T-shaped steel, H-shaped steel, etc. The volume and length of newly produced steel are large, and most of them cannot meet the requirements of direct use, so they need to be processed. Nowadays, steel pipe laser cutting machines are widely used for cutting and engraving metal plates, steel sections, and pipes.

[0003] The cutting principle of the steel tube laser cutting machine is not much different from that of the plate laser cutting machine. As a special laser cutting machine, the steel laser cutting machine is mainly used for laser cutting of standard metal tubes (round tubes, rectangular tubes, elliptical tubes, etc.), profiles (channel steel, angle steel, etc.) and some special-shaped tubes. Through the traditional auxiliary rotating steel structure, the traditional steel laser cutting laser head can process small steels, and the laser head does not need to rotate in space. However, if large steels need to be processed, such as marking, beveling, and hole cutting, steel laser cutting equipment is required. The laser head needs to move according to the processing position of the steel. Therefore, the CAM software needs to optimize the spatial trajectory cutting path and connect multiple processing contour paths with jump lines.

[0004] like Figure 1 As shown, the laser cutting head needs to change the normal direction and spatial position of the cutting in the positions marked 1, 2, 3, and 4 in the figure, and it is necessary to prevent collisions from occurring during the transformation to prevent damage to the steel section and the cutting head. The jump line refers to the movement trajectory of the laser cutting head between the two cutting paths. The reasonable generation of the jump line can not only improve the processing efficiency, but also avoid the collision between the cutting head and the steel section, thereby ensuring the safety and accuracy of the cutting process. At present, there is no related technology for the jump line generation method based on the geometric information of the laser cutting contour of the steel section. Therefore, the present invention mainly proposes a jump line generation method based on the geometric information of the laser cutting contour of the steel section, which ensures that the laser head jumps efficiently during cutting, the path is optimal, and collisions are avoided. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the present invention provides a jump line generation method based on the geometric information of the laser cutting contour of steel sections, so as to generate the jump line of the path to be processed and solve the technical problems such as low efficiency, detour trajectory, possible collision, etc. in the jump line between two paths to be processed during the processing of rotating materials and steel.

[0006] To achieve the above object, according to one aspect of the present invention, a method for generating a jump line based on the geometric information of the profile laser cutting of a steel section is provided, comprising the following steps:

[0007] S1 obtains the start and end point information: obtains the coordinates of the start and end points and the corresponding normal vector direction from the cutting trajectory information of the steel to be processed;

[0008] S2 calculates the corresponding points on the circumscribed circle of the jump line: according to the information of the starting point and the end point obtained in step S1, the corresponding points on the circumscribed circle are calculated;

[0009] S3 obtains adjustment path information: three pieces of adjustment path information are obtained based on the starting point, the end point, and corresponding points on the circumscribed circle;

[0010] S4 combines the jump lines: combines the three adjustment path information obtained in step S3 to construct a completed jump line.

[0011] Preferably, the method for obtaining the first adjustment path in step S3 is: connecting the starting point and the projection of the starting point on the circumscribed circle by a straight line, and interpolating discrete points to form the first adjustment path, wherein the normal vector direction of the discrete points is the same as the normal vector of the starting point.

[0012] Preferably, the method for obtaining the second adjustment path in step S3 specifically includes the following steps: determining whether the normal vectors of the start and end points are parallel, and whether the coordinates of the start and end points are the same;

[0013] ① If the normal vectors of the start and end points are parallel, use a straight line to connect the start and end points on the circumscribed circle to form the second discrete point of the adjustment path;

[0014] ② If the coordinates of the start and end points are the same, an arc is formed by projecting the circumscribed circle and the coordinates of the start and end points, and the discrete points of the arc are used as the discrete points of the second adjustment path;

[0015] ③ If the coordinates of the starting and ending points are different, adjust the coordinates according to the starting point of the circumscribed circle to obtain the discrete points of the second adjusted path.

[0016] ④ According to the requirements of the processing trajectory, on the basis of steps ①②③, add an intermediate point to divide the second adjustment path into two parts. After solving, merge the two parts to obtain the discrete points of the second adjustment path.

[0017] Preferably, the method for obtaining the third adjustment path in step S3 is: calculate the normal vector direction of the end point on the circumscribed circle, and calculate the normal vector of the discrete point by arc discrete interpolation; connect the end point and the end point of the circumscribed circle, interpolate the discrete points and generate a third adjustment path, and the normal vector of the discrete point is consistent with the normal vector of the end point.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects:

[0019] 1. The present invention generates multiple adjustment path information (Edge1, Edge2, Edge3) by using discrete points and normal vector interpolation, and finally constructs a smooth and continuous jump turning line. This method can effectively handle the curve generation problem between the starting and ending points under different circumstances, especially has a wide range of applications in three-dimensional space, and can improve the accuracy and flexibility of trajectory planning.

[0020] 2. The present invention automatically obtains the start and end point coordinates and the normal vector based on the geometric contour information of the steel section, and automatically generates a jump line. Since the jump is based on the circumscribed circle and is suitable for cylindrical laser cutting fields such as steel section cutting, it can achieve beneficial effects such as short jump line distance, collision prevention, and minimum normal vector transformation angle.

[0021] 3. The present invention can handle special scenarios such as gantry laser cutting through the segmented path processing method. When processing the segmented path, an intermediate point is introduced to ensure that the jump line is not located under the steel section, which can ensure the safety and special requirements during cutting. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the steel jump line;

[0023] Figure 2 This is a schematic diagram of the steel section jump line trajectory.

[0024] Figure 3 It is a schematic diagram of the circumscribed circle of the steel section jump line.

[0025] Figure 4 This is a schematic diagram of the steel section jump line trajectory.

[0026] Figure 5 Customize the path diagram for the steel jump line trajectory.

[0027] Figure 6 Schematic diagram of the process of this method. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0029] This application does not make a strict distinction between trajectory and contour, which can be understood as synonyms in the context of this article, that is, processing trajectory contour, and processing trajectory or processing contour refer to the same meaning throughout the text.

[0030] Example 1

[0031] See also Figure 1-6 The present invention provides a method for generating a jump line based on the geometric information of the profile laser cutting of steel, comprising the following steps:

[0032] S1 obtains the start and end point information: obtains the coordinates of the start and end points and the corresponding normal vector direction from the cutting trajectory information of the steel to be processed;

[0033] That is, in order to calculate the jump line from the starting point StartPt to the end point EndPt, the following parameters are required:

[0034] StartPt: starting point, three-dimensional coordinates (x, y, z)

[0035] StartVec: unit normal vector of the starting point, three-dimensional coordinates (x, y, z)

[0036] EndPt: end point, three-dimensional coordinates (x, y, z)

[0037] EndVec: unit normal vector of the end point, three-dimensional coordinates (x, y, z)

[0038] S2 calculates the corresponding points of the circumscribed circle of the jump line: according to the normal vector direction of the starting point and the position of the end point, calculates the corresponding points on the circumscribed circle;

[0039] The positions on the circumscribed circle of the steel or pipe to be processed are the circumscribed circle start point (OStartPt) and the circumscribed circle end point (OEndPt). In order to avoid collision and calculation errors, the H position outside the circumscribed circle radius is introduced as the auxiliary circumscribed circle (AssistantOuterCircle), and the positions on the auxiliary circumscribed circle, the auxiliary circumscribed circle start point AOStartPt and the auxiliary circumscribed circle end point AOEndPt, are found. The point graphic information is as follows: Figure 2 As shown. To simplify the description, the auxiliary circumscribed circle is referred to as the circumscribed circle below. The jump line is represented by discrete point coordinates in space, and each discrete point position has corresponding normal vector information of the cutting head.

[0040] S3 obtains adjustment path information: three pieces of adjustment path information are obtained based on the starting point, the end point, and corresponding points on the circumscribed circle;

[0041] Step S3 specifically includes the following steps:

[0042] S31 obtains a first adjustment path: connects the starting point and the projection of the starting point on the circumscribed circle through a straight line, and interpolates discrete points to form the first adjustment path, wherein the direction of the normal vector of the discrete points is the same as the normal vector of the starting point;

[0043] S32 obtains the second adjustment path: determines whether the normal vectors of the start and end points are parallel, and whether the coordinates of the start and end points are the same;

[0044] ① If the normal vectors of the start and end points are parallel, use a straight line to connect the start and end points on the circumscribed circle to form the second discrete point of the adjustment path;

[0045] ② If the coordinates of the start and end points are the same, an arc is formed by projecting the circumscribed circle and the coordinates of the start and end points, and the discrete points of the arc are used as the discrete points of the second adjustment path;

[0046] ③ If the coordinates of the starting and ending points are different, adjust the coordinates according to the starting point of the circumscribed circle to obtain the discrete points of the second adjustment path;

[0047] ④ According to the requirements of the processing trajectory, on the basis of steps ①②③, add an intermediate point to divide the second adjustment path into two parts. After solving, merge the two parts to obtain the discrete points of the second adjustment path;

[0048] S33 obtains the third adjustment path: calculates the normal vector direction of the end point on the circumscribed circle, and calculates the normal vector of the discrete point by arc discrete interpolation; connects the end point and the end point of the circumscribed circle, interpolates the discrete points and generates the third adjustment path, the normal vector of the discrete point is consistent with the normal vector of the end point.

[0049] S4 combines the jump lines: combines the three adjustment path information obtained in step S3 to construct a completed jump line.

[0050] The jump line trajectory is the motion trajectory of the laser cutting head. The specific path is divided into the following three stages:

[0051] 1) Moving from the starting point StartPt to the starting point AOStartPt of the circumscribed auxiliary circle is the first adjustment path (the first adjustment path is recorded as Edge1), which is composed of a set of discrete points. The discrete points include coordinates and corresponding normal vectors.

[0052] 2) Moving from the starting point AOStartPt of the circumscribed auxiliary circle to the end point AOEndPt of the circumscribed auxiliary circle is the second adjustment path (the second adjustment path is recorded as Edge2), which is composed of a set of discrete points, and the discrete points include coordinates and corresponding normal vectors.

[0053] 3) Moving from the end point AOEndPt of the circumscribed auxiliary circle to the end point EndPt is the third adjustment path (the third adjustment path is recorded as Edge3), which is composed of a set of discrete points, and the discrete points include coordinates and corresponding normal vectors.

[0054] During the whole process, it is also necessary to adjust the normal direction corresponding to the discrete points of the path Edge. The normal vector of the discrete point corresponds to the normal direction of the laser head to ensure a smooth transition.

[0055] The following are the specific steps to calculate the coordinates of the points on the circumscribed circle mentioned above and the discrete point information and normal information of the three edges:

[0056] (1) Calculate the positions of the start and end points of the jump line on the circumscribed circle.

[0057] The coordinates of AOStartPt are calculated based on the known point information and the angle between the normals. Since the longitudinal direction of the steel section corresponds to the X-axis direction, the X coordinates of the discrete points in Edge1 and Edge3 remain unchanged during the jump, so the coordinates of AOStartPt and AOEndPt can be calculated on the YZ plane.

[0058] Taking EndPt(x2, y2, z2) of the embodiment as an example, it is introduced how to calculate the parameters of AOEndPt on the circumscribed circle, that is, the coordinate value of AOEndPt, according to the coordinates and direction vector.

[0059] Figure 3 The information that needs to be supplemented is: AOEndPt is the end point, EndPt (x2, y2, z2) is the starting point, and EndVec is the direction of the point on the circumscribed circle. Connect AOEndPt and EndPt as a straight line L, and connect the center O and the end point EndPt as a straight line R1. Connect the center O and the end point AOEndPt on the circumscribed circle as a straight line R2. The length of R2 is the length of R1 plus the extra distance H mentioned above to prevent collision, that is, R1 = R2 + H, which are all known conditions.

[0060] First, according to the EntPt coordinates (X, Y, Z), the inverse tangent algorithm is used to obtain the angle θ1 formed by R1 and the positive direction of the Y axis, that is, Theta1. Then, according to EndVec(x v ,y v ,z v ) to obtain the angle θ2 formed by the normal and the positive direction of Y, namely Theta2, which is the angle between L and the positive direction of the Y axis. Therefore, the angle θ3 between L and R1, namely Theta3, can be obtained. According to the known lengths of R1 and R2, the length of L can be calculated by the triangular cosine theorem. According to the length of L and the EntVec vector, the coordinates of AOEntPt can be obtained by multiplying the vector by L plus the coordinates of EndPt. The calculation process is as follows:

[0061] θ1=atan2(y1,z1)

[0062] θ2=atan2(y v ,z v )

[0063] θ3=θ2-θ1

[0064]

[0065] AOEndPt coordinates are (x2,y2+L*y v ,z2+L*z v )

[0066] Similarly, the coordinates of AOStartPt can be obtained.

[0067] (2) Calculate the discrete points that make up Edge1 and Edge3: Edge1 can be directly connected to StartPt and AOStartPt with a straight line. Therefore, the coordinates of the discrete points of Edge1 can be directly obtained by discrete interpolation based on the coordinates of StartPt and AOStartPt. That is, according to the count of discrete points and the length of the straight line, the coordinates (x i ,y i ,z i ) can be:

[0068]

[0069] At the same time, the normal vectors of all discrete points of Edge1 can be directly set to StartVec which is consistent with the normal vector of StartPt.

[0070] The method of adding Edge3 is similar to that of Edge1, which is to directly connect AOEndPt and EndPt with a straight line.

[0071] (3) Calculate the discrete points that make up Edge2

[0072] (3.1) If the corresponding normal vectors of the starting point and the end point are parallel, or the Y and Z coordinates of the starting point and the end point on the corresponding points on the circumscribed circle are the same

[0073] This situation shows that there is no need to use B-spline fitting. Just connect AOStartPt and AOEndPt with a straight line. The discrete point calculation is consistent with the method described above. The normal vectors are kept consistent with the normal vectors of the starting point or end point.

[0074] (3.2) Other general situations

[0075] as follows Figure 4As shown in the figure, Edge2 should be a spline around the circumscribed circle surface. If this line is projected onto the YZ plane, it is an arc from AOStartPt(x1,y1,z1) to AOEndPt(x2,y2,z2). Therefore, when calculating the parameters of Edge2, you can first construct an arc from AOStartPt to AOEndPt. After discretizing this arc, if the number of discrete points is count, discretize it into count discrete values ​​according to the X coordinate values ​​of AOStartPt and AOEndPt, and modify the X coordinates of the discrete points of the discretized arc to these count discrete values, and you will get the coordinates of each discrete point of Edge2.

[0076] The center of the arc is (x c ,y c ,z c ), calculate the angles corresponding to the start and end points of the arc. Assume that the angle corresponding to the start point is θ1 and the angle corresponding to the end point is θ2.

[0077] It can be calculated by inverse trigonometric functions:

[0078] θ1=arctan 2(z1-z c ,y1-y c )

[0079] θ2=arctan 2(z2-z c ,y2-y c )

[0080] Discrete count angle values ​​within the angle range θ1, θ2, and the increment of each angle is:

[0081] y i =y c +r·cos(θ i )

[0082] z i =z c +r·sin(θ i )

[0083] Based on the given X coordinate starting point x1 and end point x2, discretize into count X coordinate values. The increment of each X coordinate is:

[0084]

[0085] The discretized i-th X coordinate is:

[0086] x i =x1+i·Δx(i=0,1,2,…,count-1)

[0087] The coordinates of the ith discrete point of Edge2 are: (x i ,y i ,z i ).

[0088] When calculating the normal vector of the discrete points of Edge2, the polar coordinate method can be used. First, the normal vectors of the start and end points (StartVec and EndVec) are normalized to ensure that they are unit vectors. Then, the angle between them is obtained by calculating the dot product of the two vectors. In order to eliminate numerical errors, the dot product value is limited to the range of [-1.0, 1.0], and the angle is calculated using the inverse cosine function. Next, the intermediate vector is calculated by interpolation. According to the specified number of discrete points, the interpolation factor is calculated one by one, and the spherical linear interpolation method (SLERP) is used to interpolate between the start vector and the end vector. Finally, the intermediate vector obtained by interpolation is normalized and stored in the result normal vector container as the normal vector of the discrete points of Edge2, which is convenient for use as a direction reference for the spatial trajectory of the laser cutting head. This method ensures a smooth transition of the normal vector from the start point to the end point, providing a natural normal vector change.

[0089] The relevant calculation formula is: The normalized expression of the starting point normal vector StartVec and the end point normal vector EndVec is as follows:

[0090]

[0091] The dot product of two unit vectors can be expressed as:

[0092] cosθ=StartVec·EndVec

[0093] In order to eliminate numerical errors, the dot product value is limited to the range [-1,1]:

[0094] cosθ=min(max(StartVec·EndVec,-1.0),1.0)

[0095] Then use the inverse cosine function to calculate the angle θ between them:

[0096] θ=arccos(cosθ)

[0097] Suppose we need to interpolate N discrete points, and the interpolation factor is t, where t ranges from 0 to 1.

[0098] For each discrete point The spherical linear interpolation formula is:

[0099]

[0100] To ensure that each interpolated intermediate vector Vec(t i) is also a unit vector, normalized:

[0101]

[0102] (4) For some specific scenarios, such as gantry laser cutting, the laser cutting head cannot cut from bottom to top, so the natural cutting trajectory cannot be in the negative half-axis area of ​​the Z axis. Therefore, it is necessary to ensure that the added jump line cannot be located under the steel section, such as Figure 5 As shown, when adding a jump line, Edge2 should follow path 1 (Path1) instead of the shorter path 2 (Path2). An intermediate point MidPt can be used to ensure that Edge2 is located on the steel section, that is, it follows path 1. The coordinates of MidPt are the coordinates of the midpoint of the arc determined by the start and end points. When calculating Edge2, first calculate the path from the starting point AOStartPt on the circumscribed circle to the intermediate point MidPt, and the path from the intermediate point MidPt to the end point AOEndPt of the circumscribed circle, and then merge these two paths into Edge2. The discrete point coordinate calculation method and the normal vector assignment method are consistent with the steps described in the previous article (3).

[0103] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for generating jump lines based on the geometric information of the profile laser cutting of steel, characterized in that: The following steps are involved: S1 obtains the start and end point information: obtains the coordinates of the start and end points and the corresponding normal vector direction from the cutting trajectory information of the steel to be processed; S2 calculates the corresponding points on the circumscribed circle of the jump line: according to the information of the starting point and the end point obtained in step S1, the corresponding points on the circumscribed circle are calculated; S3 obtains adjustment path information: three pieces of adjustment path information are obtained based on the starting point, the end point, and corresponding points on the circumscribed circle; S4 combines the jump lines: combines the three adjustment path information obtained in step S3 to construct a completed jump line.

2. A method for generating jump lines based on geometric information of profile laser cutting as claimed in claim 1, characterized in that: The method for obtaining the first adjustment path in step S3 is: connecting the starting point and the projection of the starting point on the circumscribed circle by a straight line, and interpolating discrete points to form the first adjustment path, wherein the normal vector direction of the discrete points is the same as the normal vector of the starting point.

3. A method for generating jump lines based on geometric information of profile laser cutting as claimed in claim 1, characterized in that: The method for obtaining the second adjustment path in step S3 specifically includes the following steps: determining whether the normal vectors of the start and end points are parallel, and whether the coordinates of the start and end points are the same; ① If the normal vectors of the start and end points are parallel, use a straight line to connect the start and end points on the circumscribed circle to form the second discrete point of the adjustment path; ② If the coordinates of the start and end points are the same, an arc is formed by projecting the circumscribed circle and the coordinates of the start and end points, and the discrete points of the arc are used as the discrete points of the second adjustment path; ③ If the coordinates of the starting and ending points are different, adjust the coordinates according to the starting point of the circumscribed circle to obtain the discrete points of the second adjusted path.

4. A method for generating jump lines based on geometric information of profile laser cutting as claimed in claim 3, characterized in that: It also includes step ④, according to the requirements of the processing trajectory, on the basis of steps ①②③, adding an intermediate point to divide the second adjustment path into two parts, and after solving, merging the two parts to obtain the discrete points of the second adjustment path.

5. A method for generating jump lines based on geometric information of profile laser cutting as claimed in any one of claims 1 to 4, characterized in that: The method for obtaining the third adjustment path in step S3 is: calculate the normal vector direction of the end point on the circumscribed circle, and calculate the normal vector of the discrete point by arc discrete interpolation; connect the end point and the end point of the circumscribed circle, interpolate the discrete points and generate a third adjustment path, and the normal vector of the discrete point is consistent with the normal vector of the end point.

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