Intersecting line trajectory planning method with simple demonstration

Abstract

The invention discloses an intersecting line trajectory planning method with simple demonstration, which relates to the technical field of welding, and comprises the following steps: step 1, modeling an intersecting line: simplifying an intersecting line model based on a workpiece coordinate system, identifying radiuses of a main pipe and a branch pipe through demonstration points, meanwhile, the position and posture of the original point of the workpiece coordinate system in the world coordinate system are determined; step 2, demonstration of an intersecting line and generation of a track path: setting four modeling points on a main pipe; the teaching mode is very simple, a large number of point positions are not needed, the intersecting line track can be demonstrated through four points, the whole positioning process is simplified, operation is easy, time and labor are saved, the phenomenon that the teaching time is too long is avoided, production efficiency is improved, and production cost is reduced; the track mode generated by the algorithm is simple and reliable, frequent adjustment and optimization are avoided, it is ensured that the generated track is the intersecting line of the standard brick, the accuracy of the welding path is ensured, and the welding quality is improved.

Description

Technical Field

[0001] The invention relates to the technical field of welding, and in particular to a method for planning an intersecting line trajectory with simple teaching. Background Art

[0002] The teaching method of simple intersection trajectory planning is a method of setting the trajectory that the robot needs to follow when processing the intersection line (i.e. the intersection line formed by the intersection of two solids) through manual teaching in automated processing or robot operation. This method usually combines elements of human intervention and machine learning to simplify the process of complex trajectory planning and improve efficiency and accuracy.

[0003] In the prior art, for the welding of intersecting lines, spline curves or arcs are usually used for fitting approximation. This approximation method has significant defects: the fitting trajectory is not a standard intersecting line, resulting in inherent errors in the welding path, and in order to ensure the welding quality, a large number of points need to be taught, which is cumbersome and time-consuming. In some cases, the teaching time is even longer than the manual direct welding time, which seriously affects the production efficiency.

[0004] Therefore, it is necessary to propose a simple teaching method for intersecting line trajectory planning to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a method for planning intersection line trajectories with simple teaching, so as to solve the problem that the fitting trajectory is not a standard intersection line, resulting in inherent errors in the welding path, and in order to ensure the welding quality, a large number of points need to be taught, the operation is cumbersome and time-consuming, and the teaching time may even be longer than the manual direct welding time, which seriously affects the production efficiency.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for teaching simple intersecting line trajectory planning, comprising the following steps:

[0007] Step 1: Model the intersection line: Simplify the intersection line model based on the workpiece coordinate system, identify the radius of the main pipe and branch pipe through the teaching point, and determine the position and posture of the origin of the workpiece coordinate system in the world coordinate system;

[0008] Step 2: Teaching of intersection lines and generation of trajectory paths: Set four modeling points on the main pipe to determine the workpiece coordinate system posture, workpiece coordinate system position and radius; determine the trajectory of the intersection line in the world coordinate system based on the data parameters;

[0009] Step 3: Intersecting line trajectory posture generation: The path information of the trajectory corresponds to the posture information one by one. The calculation process of the tangent and normal plane is obtained through the implicit function equation group of the intersecting line. The directions of the x-axis and z-axis are obtained through calculation, and the cross product of the x-axis and the z-axis obtains the direction of the y-axis.

[0010] Preferably, the workpiece includes a main pipe and a branch pipe, the main pipe is a cylinder with a large radius, the main pipe radius is R, the branch pipe is a cylinder with a small radius, the branch pipe radius is r, the workpiece coordinate system is used to simplify the intersection line model, the intersection of the axes of the workpiece is the origin o of the coordinate system, the axis of the main pipe is the y-axis, and the axis of the branch pipe is the z-axis;

[0011] The parametric equation of the intersection line is:

[0012]

[0013] Preferably, any point on the intersection line is set as P, the coordinates of point P are x, y, z, the point where the intersection line is projected on the workpiece coordinate system oxy plane is denoted as P', and the angle between the line from the coordinate system origin o to P' and the x-axis of the workpiece coordinate system is denoted as φ.

[0014] Preferably, the branch pipe is located in the vertical upward direction of the main pipe, and the intersection line is provided with P1, P2, P3, P4, P5 and P6, the two points at the high point of the intersection line are P1 and P3, the two points at the low point of the intersection line are P2 and P4, and P5 and P6 are used to set the starting point and end point of the track;

[0015] P1 and P3 determine the y direction of the workpiece coordinate system, P2 and P4 determine the x direction of the workpiece coordinate system, the cross product of P1, P3 and P2, P4 is the z axis, and the transformation matrix corresponding to the z axis is R wp ;

[0016] The projection coordinates of P1-P4 along the y-axis direction under oxz are P1'-P4', and the main tube radius R can be obtained by P1'-P4'. The coordinates of P1'-P4' and the origin of the working coordinate system in the world coordinate system are x wp and z wp ;

[0017] The projection coordinates of P1-P4 along the z-axis in oxy are P1"-P4", and the radius r of the main tube can be obtained by P1"-P4", and the coordinates y of the origin of the working coordinate system in the world coordinate system are wp ;

[0018] The trajectory equation of the intersection line in the workpiece coordinate system is:

[0019]

[0020] The pose transformation matrix of the workpiece coordinate system relative to the world coordinate system is:

[0021]

[0022] The trajectory of the workpiece coordinate system in the world coordinate system is:

[0023]

[0024] The independent variable of the intersection line trajectory equation is φ, and φ is used for speed planning to generate the trajectory interpolation points of the intersection line.

[0025] Preferably, the calculation of the tangent line and the normal plane needs to be performed on any curve and a point on the curve, and the specific calculation method is as follows:

[0026] For any curve, its parametric equation can be expressed as:

[0027]

[0028] The tangent vector at a point M(x0,y0,z0) on the curve is:

[0029]

[0030] The equation of the tangent line at a point on the curve is

[0031]

[0032] The normal plane equation is:

[0033]

[0034] Preferably, the calculation process of the posture of the intersection line at any point is as follows:

[0035] The implicit function equation of the intersection line is:

[0036] F(x,y,z)=x 2 +y 2 -r 2

[0037] G(x,y,z)=x 2 +z 2 -R 2 .

[0038] Preferably, the point P on the intersection line is the tangent direction of the x-axis, and the z-axis bisects the dihedral angle of the section formed by the main pipe and the branch pipe.

[0039] Preferably, the direction calculation equations of the x-axis, y-axis and z-axis are as follows:

[0040] S1, the specific calculation equation for the direction of the x-axis is as follows:

[0041]

[0042] S2, the intersection line between the plane perpendicular to the z-axis at point P and the cylindrical surface of the main tube is the trajectory C1, and the specific calculation equation for the direction of the z-axis is as follows:

[0043]

[0044] x 2 +y 2 -R 2 = 0; the intersection of the plane perpendicular to the z-axis at point P and the cylindrical surface of the branch pipe is trajectory C2, and the tangent vector of trajectory C2 at point P The z-axis direction is (q1+q2) / 2;

[0045] S3. Direction of the y-axis: The cross product of the x-axis and the z-axis can obtain the y-axis.

[0046] Technical effects and advantages of the present invention:

[0047] 1. The teaching method of the present invention is very simple, without a large number of points, four points can teach the intersection line trajectory, simplifying the entire positioning process, simple operation, saving time and effort, avoiding long teaching time, improving production efficiency and reducing production costs.

[0048] 2. The trajectory generated by the algorithm is concise and reliable, avoiding frequent adjustments and optimizations, ensuring that the generated trajectory is the intersection line of the standard bricks, ensuring the accuracy of the welding path, and improving the welding quality;

[0049] 3. During operation, the trajectory speed and posture can be adjusted arbitrarily, which is convenient for operators to flexibly adjust the processing parameters according to actual conditions, simplifying the operation process and improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 The present invention is a schematic diagram of the flow chart of a simple intersection line trajectory planning method.

[0051] Figure 2 This is a first schematic diagram of the intersection line model of the present invention.

[0052] Figure 3 This is a second schematic diagram of the intersection line model of the present invention. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments, and they should not be understood as limitations on the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. In the description of the present invention, it should be understood that the terms used are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0054] The present invention aims to solve the problem that the fitting trajectory is not a standard intersection line, resulting in inherent errors in the welding path, and in order to ensure the welding quality, a large number of points need to be taught, the operation is cumbersome and time-consuming, and even the teaching time is longer than the manual direct welding time, which seriously affects the production efficiency. Figure 1-Figure 3 A simple teaching method for planning the trajectory of an intersecting line is shown, comprising the following steps:

[0055] Step 1: Model the intersection line: Simplify the intersection line model based on the workpiece coordinate system, identify the radius of the main pipe and the branch pipe through the teaching points, and determine the position and posture of the origin of the workpiece coordinate system in the world coordinate system; introduce a workpiece coordinate system to simplify the intersection line model, identify the radius of the main pipe and the branch pipe through the teaching points, and the position and posture of the origin of the workpiece coordinate system in the world coordinate system.

[0056] Step 2: Teaching of intersection lines and generation of trajectory paths: Set four modeling points on the main pipe to determine the workpiece coordinate system posture, workpiece coordinate system position and radius; determine the trajectory of the intersection line in the world coordinate system based on the data parameters; when teaching, a total of four modeling points are required, through which the workpiece coordinate system posture, workpiece coordinate system position and radius can be obtained.

[0057] Step 3: Intersecting line trajectory posture generation: The path information of the trajectory corresponds to the posture information one by one. The calculation process of the tangent and normal plane is obtained through the implicit function equation group of the intersecting line. The directions of the x-axis and z-axis are obtained through calculation, and the cross product of the x-axis and z-axis obtains the y-axis direction. In the actual operation of the trajectory, in addition to the path information, the corresponding appropriate posture information is also required to ensure the welding quality and avoid collision.

[0058] In the present invention, the workpiece includes a main pipe and a branch pipe, the main pipe is a cylinder with a large radius, the main pipe radius is R, the branch pipe is a cylinder with a small radius, the branch pipe radius is r, the workpiece coordinate system is used to simplify the intersecting line model, the intersection of the axis of the workpiece is the origin o of the coordinate system, the main pipe axis is the y-axis, and the branch pipe axis is the z-axis; the workpiece coordinate system is used to simplify the intersecting line model, the intersection of the main pipe axis and the branch pipe axis is the origin o of the workpiece coordinate system, the main pipe axis determines the Y-axis direction, and the branch pipe axis determines the z-axis direction;

[0059] The parametric equation of the intersection line is

[0060]

[0061]

[0062] It should be noted that any point on the intersection line is set as P, the coordinates of point P are x, y, z, the point of the intersection line projection on the workpiece coordinate system oxy plane is denoted as P', and the angle between the line connecting the origin o of the coordinate system to P' and the x-axis of the workpiece coordinate system is denoted as φ; take any point P (x, y, z) on the intersection line, its point of projection on the workpiece coordinate system oxy plane is denoted as P', and the angle between the line connecting the origin o of the coordinate system to P' and the x-axis of the workpiece coordinate system is denoted as φ, this parameter will be used as the independent variable of the intersection line trajectory.

[0063] In the present invention, the branch pipe is located in the vertical upward direction of the main pipe, and the intersection lines are set with P1, P2, P3, P4, P5 and P6. The two points at the high point of the intersection line are P1 and P3, and the two points at the low point of the intersection line are P2 and P4. P5 and P6 are used to set the starting point and end point of the trajectory; through four modeling points, the two highest points (P1 and P3) and the two lowest points (P2 and P4) of the intersection line, as well as the starting point and end point P5 and P6 of the trajectory are determined.

[0064] Through the above operation, the teaching method becomes very simple. Without a large number of points, four points can teach the intersecting line trajectory, simplifying the entire positioning process, simple operation, saving time and effort, avoiding long teaching time, improving production efficiency and reducing production costs.

[0065] Furthermore, P1 and P3 determine the y direction of the workpiece coordinate system, P2 and P4 determine the x direction of the workpiece coordinate system, and the cross product of P1, P3 and P2, P4 is the z-axis. The transformation matrix corresponding to the z-axis is R wp ; Because of the special point selection, P1 and P3 determine the y direction of the workpiece coordinate system, P2 and P4 determine the x direction of the workpiece coordinate system, and the cross product obtains the z-axis direction. The corresponding transformation matrix is ​​R wp (wp is the abbreviation of workpiece).

[0066] It should be noted that the projection coordinates of P1-P4 along the y-axis in the oxz direction are P1'-P4', P1'-P4' can be used to obtain the main tube radius R, and the coordinates of P1'-P4' and the origin of the working coordinate system in the world coordinate system are x wp and z wp ; In the workpiece coordinate system, the projection coordinates of P1-P4 along the y-axis in the oxz direction are recorded as P1'-P4'. Through P1'-P4', the radius R of the main tube and the coordinate x of the origin of the workpiece coordinate system in the world coordinate system can be obtained. wp and z wp .

[0067] It should also be noted that the projection coordinates of P1-P4 along the z-axis in oxy are P1"-P4", P1"-P4" can be used to obtain the main tube radius r, P1"-P4" and the coordinate y of the origin of the working coordinate system in the world coordinate system wp ; In the workpiece coordinate system, the projection coordinates of P1-P4 along the z-axis in oxy are recorded as P1"-P4". Through P1"-P4", the radius of the main tube r and the coordinate y of the origin of the workpiece coordinate system in the world coordinate system can be obtained. wp .

[0068] The trajectory equation of the intersection line in the workpiece coordinate system is:

[0069]

[0070] The pose transformation matrix of the workpiece coordinate system relative to the world coordinate system is:

[0071]

[0072] The trajectory of the workpiece coordinate system in the world coordinate system is

[0073]

[0074] The independent variable of the intersection line trajectory equation is φ, and the velocity planning of φ is used to generate the trajectory interpolation points of the intersection line; thus, the intersection line trajectory equation with φ as the independent variable is obtained, and the trajectory interpolation points of the intersection line are generated by velocity planning of φ.

[0075] The trajectory generated by the algorithm is concise and reliable, avoiding frequent adjustments and optimizations, ensuring that the generated trajectory is the intersection line of the standard bricks, ensuring the accuracy of the welding path, and improving the welding quality.

[0076] In the present invention, the calculation of the tangent line and the normal plane needs to be performed on any curve and a point on the curve. The specific calculation method is as follows:

[0077] For any curve, its parametric equation can be expressed as:

[0078]

[0079] The tangent vector at a point M(x0,y0,z0) on the curve is:

[0080]

[0081] The equation of the tangent line at a point on the curve is

[0082]

[0083] The normal plane equation is:

[0084]

[0085] The calculation process of the posture of the intersection line at any point is as follows:

[0086] The implicit function equation of the intersection line is:

[0087] F(x,y,z)=x 2 +y 2 -r 2

[0088] G(x,y,z)=x 2 +z 2 -R 2 .

[0089] In the present invention, point P on the intersection line is the tangent direction of the x-axis, and the z-axis bisects the dihedral angle formed by the section formed by the main pipe and the branch pipe; for point P on the intersection line, the x-axis is recorded as the tangent direction of the intersection line, and the z-axis bisects the dihedral angle formed by the main pipe section and the branch pipe section.

[0090] The calculation equations for the directions of the x-axis, y-axis, and z-axis are as follows:

[0091] S1, the specific calculation equation for the direction of the x-axis is as follows:

[0092]

[0093] The intersection of the plane perpendicular to the z-axis at point S2 and point P and the cylindrical surface of the main tube is the trajectory C1. The specific calculation equation for the direction of the z-axis is as follows:

[0094]

[0095] x 2 +y 2 -R 2 = 0; the intersection of the plane perpendicular to the z-axis at point P and the cylindrical surface of the branch pipe is trajectory C2, and the tangent vector of trajectory C2 at point P is The z-axis direction is (q1+q2) / 2;

[0096] S3, the direction of the y-axis: The cross product of the x-axis and the z-axis can get the y-axis; through the above, any point (x p ,y p ,z p ) corresponds to the posture matrix R p .

[0097] During operation, the trajectory speed and posture can be adjusted arbitrarily, which makes it convenient for operators to flexibly adjust processing parameters according to actual conditions, simplifies the operation process and improves work efficiency.

Claims

1. A simple teaching method for planning the trajectory of an intersecting line, characterized in that: The following steps are involved: Step 1: Model the intersection line: Simplify the intersection line model based on the workpiece coordinate system, identify the radius of the main pipe and branch pipe through the teaching point, and determine the position and posture of the origin of the workpiece coordinate system in the world coordinate system; Step 2: Teaching of intersection lines and generation of trajectory paths: Set four modeling points on the main pipe to determine the workpiece coordinate system posture, workpiece coordinate system position and radius; determine the trajectory of the intersection line in the world coordinate system based on the data parameters; Step 3: Intersecting line trajectory posture generation: The path information of the trajectory corresponds to the posture information one by one. The calculation process of the tangent and normal plane is obtained through the implicit function equation group of the intersecting line. The directions of the x-axis and z-axis are obtained through calculation, and the cross product of the x-axis and the z-axis obtains the direction of the y-axis.

2. According to claim 1, a method for teaching simple intersection trajectory planning is characterized in that: The workpiece includes a main pipe and a branch pipe, the main pipe is a cylinder with a large radius, the main pipe radius is R, the branch pipe is a cylinder with a small radius, the branch pipe radius is r, the workpiece coordinate system is used to simplify the intersecting line model, the intersection of the axes of the workpiece is the origin o of the coordinate system, the axis of the main pipe is the y axis, and the axis of the branch pipe is the z axis; The parametric equation of the intersection line is:

3. A method for planning intersecting line trajectories with simple teaching according to claim 2, characterized in that: Any point on the intersection line is set as P, the coordinates of point P are x, y, z, the point of the projection of the intersection line on the workpiece coordinate system oxy plane is recorded as P', and the angle between the line connecting the origin o of the coordinate system to P' and the x-axis of the workpiece coordinate system is recorded as φ.

4. The method for planning intersecting line trajectories with simple teaching according to claim 1, characterized in that: The branch pipe is located in the vertical upward direction of the main pipe, and the intersection line is provided with P1, P2, P3, P4, P5 and P6. The two points at the high point of the intersection line are P1 and P3, and the two points at the low point of the intersection line are P2 and P4. P5 and P6 are used to set the starting point and end point of the track; P1 and P3 determine the y direction of the workpiece coordinate system, P2 and P4 determine the x direction of the workpiece coordinate system, the cross product of P1, P3 and P2, P4 is the z axis, and the transformation matrix corresponding to the z axis is R wp ; The projection coordinates of P1-P4 along the y-axis direction under oxz are P1'-P4', and the main tube radius R can be obtained by P1'-P4'. The coordinates of P1'-P4' and the origin of the working coordinate system in the world coordinate system are x wp and z wp ; The projection coordinates of P1-P4 along the z-axis direction under oxy are P1"-P4", and the radius r of the main tube can be obtained by P1"-P4", and the coordinates y of the origin of the working coordinate system in the world coordinate system wp ; The trajectory equation of the intersection line in the workpiece coordinate system is: The pose transformation matrix of the workpiece coordinate system relative to the world coordinate system is: The trajectory of the workpiece coordinate system in the world coordinate system is: The independent variable of the intersection line trajectory equation is φ, and φ is used for speed planning to generate the trajectory interpolation points of the intersection line.

5. The method for planning intersecting line trajectories with simple teaching according to claim 1, characterized in that: The calculation of the tangent line and the normal plane needs to be performed on any curve and a point on the curve. The specific calculation method is as follows: For any curve, its parametric equation can be expressed as: The tangent vector at a point M(x0,y0,z0) on the curve is: The equation of the tangent line at a point on the curve is The normal plane equation is:

6. The method for planning intersecting line trajectories with simple teaching according to claim 1, characterized in that: The calculation process of the posture of the intersection line at any point is as follows: The implicit function equation of the intersection line is: F(x,y,z)=x 2 +y 2 -r 2 G(x,y,z)=x 2 +z 2 -R 2 。 7. The method for planning intersecting line trajectories with simple teaching according to claim 2, characterized in that: The point P on the intersection line is the tangent direction of the x-axis, and the z-axis bisects the dihedral angle of the section formed by the main pipe and the branch pipe.

8. The method for planning intersecting line trajectories with simple teaching according to claim 7, characterized in that: The direction calculation equations of the x-axis, y-axis and z-axis are as follows: S1, the specific calculation equation for the direction of the x-axis is as follows: S2, the intersection line between the plane perpendicular to the z-axis at point P and the cylindrical surface of the main tube is the trajectory C1, and the specific calculation equation for the direction of the z-axis is as follows: x 2 +y 2 -R 2 = 0; the intersection of the plane perpendicular to the z-axis at point P and the cylindrical surface of the branch pipe is trajectory C2, and the tangent vector of trajectory C2 at point P The z-axis direction is (q1+q2) / 2; S3. Direction of the y-axis: The cross product of the x-axis and the z-axis can obtain the y-axis.

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