A method for generating a jump line based on profile laser cutting contour geometric information

Abstract

The application discloses a jump line generation method based on profile laser cutting contour geometric information, extracts the start and end points of corresponding geometric information based on given geometric information, then obtains the coordinates on the circumscribed circle in the direction of the corresponding normal vector, then generates corresponding three-dimensional space jump lines, simultaneously calculates the discrete point coordinates of the jump lines and the direction vectors of the discrete points generated by circular arc discrete interpolation, and can introduce intermediate points for special scenes, so that the machining path meets the actual scene requirements, for example, the path is always located on the upper part, the intermediate points can be arranged on the upper part, and collision and interference can be avoided.

Description

Technical Field

[0001] This invention relates to the field of laser cutting technology, and specifically to a method for generating jump lines based on the geometric information of the laser cutting profile of steel. Background Technology

[0002] There are many types of steel, including steel pipes, steel plates, T-beams, and H-beams. Freshly produced steel is often very large in volume and length, and most of it does not meet the requirements for direct use, so it needs to be processed. Nowadays, laser cutting machines for steel pipes are widely used for cutting and engraving metal sheets, sections, and pipes.

[0003] The cutting principle of steel pipe laser cutting machines is not much different from that of sheet metal laser cutting machines. As a specialized laser cutting machine, steel laser cutting machines are mainly used for laser cutting of standard metal pipes (round pipes, rectangular pipes, elliptical pipes, etc.), profiles (channel steel, angle steel, etc.), and some irregularly shaped pipes. Traditional steel laser cutting machines can process small steel pieces using a structure that allows the laser head to rotate in space. However, for processing large steel pieces, such as marking, beveling, and drilling, specialized steel laser cutting equipment is required. The laser head needs to move according to the processing position of the steel piece. Therefore, the CAM software needs to optimize the spatial trajectory cutting path, connecting multiple processing contour paths using jumpers.

[0004] like Figure 1 As shown, the laser cutting head needs to change its cutting normal direction and spatial position at locations labeled 1, 2, 3, and 4 in the diagram. During this process, collisions must be prevented to avoid damage to the steel profile and the cutting head. Jump lines refer to the movement trajectory of the laser cutting head between two cutting paths. Proper generation of jump lines not only improves processing efficiency but also avoids collisions between the cutting head and the steel profile, ensuring the safety and accuracy of the cutting process. Currently, there are no publicly available methods for generating jump lines based on the geometric information of the steel profile's laser cutting contour. Therefore, this invention proposes a method for generating jump lines based on the geometric information of the steel profile's laser cutting contour, ensuring efficient jumping, optimal path, and collision avoidance during laser head cutting. Summary of the Invention

[0005] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides a jump line generation method based on the geometric information of the profile of laser cutting steel, in order to generate jump lines for the processing path and solve the technical problems of low efficiency, trajectory detour and possible collision in the jump line between two processing paths during the processing of rotating materials and steel.

[0006] In order to achieve the above object, according to one aspect of the present application, a jump line generation method based on profile laser cutting contour geometric information is provided, comprising the following steps:

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

[0008] S2: calculating the corresponding point of the circumscribed circle: calculating the corresponding point on the circumscribed circle according to the start and end point information obtained in step S1;

[0009] S3: obtaining adjustment path information: obtaining three pieces of adjustment path information based on the start point, end point and corresponding point on the circumscribed circle;

[0010] S4: combining the jump line: combining the three pieces of adjustment path information obtained in step S3 to construct the completed jump line.

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

[0012] As a preferred, the method for obtaining the second adjustment path in step S3 specifically comprises the following steps: judging 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, then connecting the start and end points on the circumscribed circle by a straight line to form the discrete points of the second adjustment path;

[0014] ② If the coordinates of the start and end points are the same, then forming an arc line by the circumscribed circle and the start and end point coordinates, and taking the discrete points of the arc line as the discrete points of the second adjustment path;

[0015] ③ If the coordinates of the start and end points are different, then adjusting the coordinates of the start point on the circumscribed circle to obtain the discrete points of the second adjustment path.

[0016] ④ Based on the requirements of the processing trajectory, adding intermediate points to divide the second adjustment path into two parts on the basis of steps ①, ② and ③, solving and then combining the two parts to obtain the discrete points of the second adjustment path.

[0017] As a preferred, the method for obtaining the third adjustment path in step S3 is: calculating the normal vector direction of the end point on the circumscribed circle, and calculating the normal vector of the discrete points by discrete interpolation of the arc; connecting the end point and the end point on the circumscribed circle, interpolating the discrete points and generating the third adjustment path, and the normal vector of the discrete points is consistent with the normal vector of the end point.

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

[0019] I. The present application generates multiple adjustment path information (Edge1, Edge2, Edge3, respectively) by using discrete points and normal vector interpolation, and finally constructs a smooth and continuous jump transition line. This method can effectively handle the curve generation problem between the start and end points in different situations, especially in three-dimensional space, which can improve the accuracy and flexibility of trajectory planning.

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

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

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

[0023] Figure 2 is a schematic diagram of a profile steel jump line trajectory.

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

[0025] Figure 4 is a schematic diagram of a profile steel jump line trajectory.

[0026] Figure 5 is a schematic diagram of a profile steel jump line trajectory self-defined path.

[0027] Figure 6 is a schematic diagram of the flow of the present method. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0029] The present application does not strictly distinguish between trajectory and contour, and in the context of this document, it can be understood as a synonym, i.e. machining trajectory contour, which means the same as machining trajectory or machining contour, and the same throughout the text.

[0030] Example 1

[0031] Referring to Figures 1-6 The application provides a jump line generation method based on profile laser cutting contour geometric information, comprising the following steps:

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

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

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

[0035] StartVec: Unit normal vector of the start 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: Calculate the corresponding point of the circumscribed circle: calculate the corresponding point on the circumscribed circle according to the normal vector direction of the start point and the position of the end point;

[0039] The positions on the circumscribed circle of the profile to be processed or the pipe are the circumscribed circle start point (OStartPt) and the circumscribed circle end point (OEndPt). In order to avoid collision and calculation error, the H position outside the circumscribed circle radius is introduced as an auxiliary circumscribed circle (AssistantOuterCircle), and the auxiliary circumscribed circle start point AOStartPt and the auxiliary circumscribed circle end point AOEndPt on the auxiliary circumscribed circle are found, as shown in the point position graph information Figure 2 For simplicity of description, the auxiliary circumscribed circle will be referred to as the circumscribed circle hereinafter. 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: Obtain adjustment path information: obtain three pieces of adjustment path information based on the start point, the end point, and the corresponding point on the circumscribed circle;

[0041] Step S3 specifically comprises the following steps:

[0042] S31: Obtain the first adjustment path: connect the start point and the start point projection on the circumscribed circle by a straight line, and interpolate discrete points to form the first adjustment path, the normal vector direction of the discrete points being the same as that of the start point;

[0043] S32 Obtain the second adjustment path: judge whether the normal vector of the start and end points is parallel, and whether the coordinates of the start and end points are the same;

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

[0045] ② If the coordinates of the start and end points are the same, form an arc line by projecting the circumscribed circle and the start and end point coordinates, and take the discrete points of the arc line as the discrete points of the second adjustment path;

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

[0047] ④ According to the requirements of the machining trajectory, on the basis of steps ①②③, add intermediate points to divide the second adjustment path into two parts, solve them, and then combine the two parts to obtain the discrete points of the second adjustment path;

[0048] S33 Obtain the third adjustment path: calculate the direction of the normal vector of the end point on the circumscribed circle, and calculate the normal vector of the discrete points by arc discrete interpolation; connect the end point and the end point of the circumscribed circle, interpolate the discrete points and generate the third adjustment path, and the normal vector of the discrete point is consistent with the normal vector of the end point.

[0049] S4 Combine the jump line: combine the three adjustment path information obtained in step S3 to complete the jump line.

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

[0051] 1) Move from the start point StartPt to the start point AOStartPt of the circumscribed auxiliary circle as the first adjustment path (the first adjustment path is denoted as Edge1), which is composed of a set of discrete points, and the discrete points contain coordinates and corresponding normal vectors.

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

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

[0054] In the whole process, the normal direction corresponding to the discrete points of the adjustment path Edge also needs to be adjusted. The normal vector of the discrete point is the normal vector corresponding to the laser head, which ensures smooth transition.

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

[0056] (1) Calculate the position of the circumscribed circle where the start and end points of the jump line are located.

[0057] Calculate the coordinates of AOStartPt according to the known point position information and the included angle of the normal line. Since the profile steel is longitudinally corresponding to the X-axis direction, the X-coordinate of the discrete point inside Edge1 and Edge3 does not change when jumping, so the coordinates of AOStartPt and AOEndPt can be calculated in the YZ plane.

[0058] Take the EndPt(x2, y2, z2) of the example as an example, introduce how to calculate the parameters of AOEndPt on the circumscribed circle according to the coordinates and direction vectors, that is, the coordinate values of AOEndPt.

[0059] Figure 3 The additional information needed to be supplemented is: AOEndPt is a point on the circumscribed circle with the end point EndPt(x2, y2, z2) as the starting point, and EndVec is the direction. 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, and the length of R2 is the length of R1 plus the additional 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 algorithm of arctangent is used to get the included angle θ1 of R1 and the positive direction of Y axis, that is, Theta1, and then according to EndVec(x v , y v , z v ), the included angle θ2 of the normal line and the positive direction of Y is obtained, that is, Theta2, which is the included angle of L and the positive direction of Y axis. Therefore, the included angle θ3 of L and R1 can be obtained, and according to the known lengths of R1 and R2, the length of L can be calculated through the cosine law of triangle. According to the length of L and the EntVec vector, the coordinates of AOEndPt can be obtained by using the vector multiplication of L and 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 constituting Edge1 and Edge3: Edge1 can be directly connected with a straight line between StartPt and AOStartPt. Therefore, the coordinates of the discrete points of Edge1 can be directly interpolated according to the coordinates of StartPt and AOStartPt, that is, according to the number of discrete points count and the length of the straight line, for the i-th discrete point, its coordinates (x i ,y i ,z i ) can be:

[0068]

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

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

[0071] (3) Calculate the discrete points constituting Edge2

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

[0073] This case shows that B-spline fitting is not needed, and a straight line is directly connected between AOStartPt and AOEndPt, and the discrete point calculation is consistent with the method introduced above, and the normal vector is kept consistent with the normal vector of the start point or the end point.

[0074] (3.2) Other general cases

[0075] As follows Figure 4As shown, Edge2 should be a spline around the surface of the circumscribed circle, and if this line is projected to the YZ plane, it is a circular arc from AOStartPt(x1, y1, z1) to AOEndPt(x2, y2, z2). Therefore, when calculating the parameters of Edge2, a circular arc from AOStartPt to AOEndPt can be constructed first, and after the circular arc is discretized, if the number of discretized points is count, then according to the X coordinate values of AOStartPt and AOEndPt, the X coordinate of the discretized points of the discretized circular arc is modified to count discrete values, and the coordinates of the discretized points of Edge2 are obtained.

[0076] The center of the circular arc is (x c ,y c ,z c ), and the angles corresponding to the start point and the end point of the circular arc are calculated. It is assumed that the included angle corresponding to the start point is θ1, and the included angle corresponding to the end point is θ2.

[0077] θ1 can be calculated by the inverse trigonometric function as follows:

[0078] θ1 = arctan 2(z1-z c ,y1-y c )

[0079] θ2 = arctan 2(z2-z c ,y2-y c )

[0080] In the angle range θ1, θ2, count angle values are discretized, 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] According to the given X coordinate start point x1 and end point x2, count X coordinate values are discretized. The increment of each X coordinate is:

[0084]

[0085] Then the i-th X coordinate obtained by discretization is:

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

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

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

[0089] The relevant calculation formula is as follows: the normalized representation of the start normal vector StartVec and the end 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 value of the dot product 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 included angle θ between them:

[0096] θ=arccos(cosθ)

[0097] Assuming that N discrete points are to be interpolated, the interpolation factor t is 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(This is also a unit vector, so it undergoes normalization.)

[0101]

[0102] (4) In certain specific scenarios, such as gantry laser cutting, the laser cutting head cannot cut from bottom to top, and the natural cutting trajectory cannot be in the negative half-axis region of the Z-axis. Therefore, it is necessary to ensure that the added jumper lines are not located below the steel profile, such as... Figure 5 As shown, when adding jump lines, if Edge2 should follow path 1 instead of the shorter path 2, a midpoint MidPt can be used to ensure that Edge2 is on the steel section, i.e., following 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 start point AOStartPt on the circumcircle to the midpoint MidPt, and the path from the midpoint MidPt to the end point AOEndPt on the circumcircle, and then merge these two paths into Edge2. The method for calculating discrete point coordinates and assigning normal vectors is consistent with the steps described in (3) above.

[0103] Those skilled in the art will readily understand that the above description is merely 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 within the scope of protection of the present invention.

Claims

1. A method for generating a jump line based on profile laser cutting contour geometry information of a section steel, characterized in that, The method comprises the following steps: S1: obtaining starting point and ending point information: obtaining the coordinates of the starting point and the ending point and the corresponding normal vector direction from the cutting track information of the steel profile to be processed; S2: calculating the corresponding point of the jump line circumscribed circle: calculating the corresponding point on the circumscribed circle according to the starting point and ending point information obtained in step S1; S3: obtaining adjustment path information: obtaining three pieces of adjustment path information based on the starting point, the ending point and the corresponding point on the circumscribed circle; S3 specifically comprises the following steps: S31: obtaining the first adjustment path: connecting the starting point and the starting point projection on the circumscribed circle by a straight line, and interpolating discrete points to form the first adjustment path, the normal vector direction of the discrete points being the same as that of the starting point; S32: obtaining the second adjustment path: judging whether the normal vectors of the starting point and the ending point are parallel and whether the coordinates of the starting point and the ending point are the same; ① if the normal vectors of the starting point and the ending point are parallel or the YZ coordinates of the starting point and the ending point on the corresponding point on the circumscribed circle are the same, connecting the starting point and the ending point on the circumscribed circle by a straight line to form the discrete points of the second adjustment path; ② if the normal vectors of the starting point and the ending point are not parallel and the YZ coordinates of the starting point and the ending point are different, projecting the starting point and the ending point coordinates on the circumscribed circle to the YZ plane to form a circular arc, discretizing the circular arc into discrete points, modifying the X coordinate values of the discrete points according to the X variation values of the starting point and the ending point on the circumscribed circle to obtain the discrete point coordinates of the second adjustment path, normalizing the normal vectors of the starting point and the ending point, calculating the included angle between them by calculating the dot product of the two vectors, calculating the intermediate vectors by interpolation, calculating the interpolation factors one by one according to the specified number of discrete points, and interpolating between the starting point vector and the ending point vector by using the spherical linear interpolation method; normalizing the intermediate vector obtained by interpolation as the normal vector of the discrete points of the second adjustment path; S33: obtaining the third adjustment path: calculating the normal vector direction of the ending point on the circumscribed circle, and calculating the normal vectors of the discrete points by arc discretization interpolation; connecting the ending point and the ending point on the circumscribed circle, interpolating the discrete points and generating the third adjustment path, the normal vectors of the discrete points being consistent with the normal vector of the ending point; S4: combining the jump line: combining the three pieces of adjustment path information obtained in step S3 to complete the jump line.

2. The method of claim 1, wherein the method is based on profile geometry information of laser cutting of a section steel. S32 further comprises step ③: based on the requirements of the processing track, adding intermediate points to divide the second adjustment path into two parts on the basis of steps ① and ②, solving, and then combining the two parts to obtain the discrete points of the second adjustment path.

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