Method for converting a pipe bend data format ybc to xyz

Abstract

The application discloses a kind of elbow pipe data format YBC to XYZ conversion method, comprising: inserting data at YBC data set head end;Elbow pipe is divided into straight section and curved section, and is equivalent to mechanical arm structure;YBC data is converted into D-H parameter data;Data is handled based on mechanical arm connecting rod transformation matrix;Extract XYZ data.The method of the present application, based on the segmentation principle and local geometric characteristics of TRIZ theory, the straight section and curved section of elbow pipe are segmented, and are equivalent to the connecting rod and joint of mechanical arm;According to the geometric structure and processing principle of elbow pipe, the similarity and particularity of elbow pipe structure relative to mechanical arm structure are analyzed, and the conversion algorithm from elbow pipe processing data to D-H parameter data is designed;Based on the theory of mechanical arm connecting rod transformation, a conversion algorithm from YBC data format to XYZ data format is proposed.The method can be used in flexible assembly, elbow pipe reverse modeling and other application scenarios.

Description

Technical Field

[0001] This invention belongs to the field of mechanical engineering technology, specifically a method for converting pipe bending data format YBC to XYZ. Background Technology

[0002] The design and fabrication of pipe bends are two separate processes. Typically, 3D software is used for design, and a CNC pipe bending machine is used to bend the designed pipe into shape. During the design, fabrication, and inspection of pipe bends, data format conversion is often required.

[0003] When designing pipe bends using software such as SolidWorks and CATIA, the resulting data is XYZ data. However, CNC pipe bending machines require YBC data for operation. Therefore, the XYZ design data needs to be converted into YBC machining data during processing.

[0004] In processes such as reverse modeling of bent pipes, CAD software that does not accept YBC data, and flexible assembly, it is necessary to convert YBC data into XYZ data.

[0005] Yin Lei, Zhang Jingjing, Kong Xianguang, Chang Jiantao, and Ma Hongbo disclosed a method for converting YBC data to XYZ data in their invention patent "A Method for Converting CNC Model to CAD Model of Pipe Bending" (Patent Application No.: 201611270083.1, Publication No.: CN106709198A). This method first divides the pipe bend into straight segments and curved segments; then, it defines the starting and ending points of the straight segments as... and Where Y k This represents the feed distance of the straight line segment at the k-th XYZ coordinate; then, the formula is used... and The method involves determining the coordinates of the first and last points of each line segment in xyz coordinates; finally, the XYZ data is obtained by finding the intersection points of adjacent line segments. This method requires first determining the coordinates of the first and last points of each line segment, then finding the equation of the line containing the segment, and finally calculating the XYZ data. The calculation steps are complex and computationally intensive. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the above methods and propose a method for converting pipe bending data from YBC to XYZ. This enables rapid data format conversion in applications such as flexible assembly and reverse modeling of pipe bending.

[0007] The technical solution adopted by the present invention to achieve the above objectives is as follows:

[0008] A method for converting pipe bending data format YBC to XYZ includes the following steps:

[0009] Step 1: Imput data to make the element data of the YBC dataset consistent with that of the XYZ dataset;

[0010] Step 2: Divide the pipe bend to be determined into straight segments and curved segments, and convert the pipe bend structure into a robotic arm structure based on structural similarity.

[0011] Step 3: Establish the parameter correspondence for converting YBC data to DH data;

[0012] Step 4: Process the DH data based on the transformation matrix T of the robotic arm link transformation theory;

[0013] Step 5: Extract the XYZ data to be obtained from the transformation matrix.

[0014] The interpolated data is data (0,0,0) inserted at the beginning of the YBC dataset.

[0015] The division of the bend into straight and curved segments refers to dividing the bend into straight and curved segments based on the segmentation principles and local geometric characteristics of the TRIZ theory of bends.

[0016] The method of equating the bent pipe structure with a robotic arm structure includes: equating the straight segment with the connecting rod of the robotic arm, and equating the bent segment with the joint of the robotic arm.

[0017] The parameter correspondence for the conversion of YBC data to DH data includes:

[0018] Step 3a) Set the feed direction of the pipe bending machine to the Y-axis direction, and set the value of the offset d in the DH parameter to 0;

[0019] Step 3b) The rotation angle B value in the YBC data is equal to the joint angle θ value in the DH parameters, and the bending angle C value is equal to the twist angle α value in the DH parameters;

[0020] Step 3c) The relationship between the link length a value in the DH parameters and the Y value in the YBC data.

[0021] The relationship between the value of the link length 'a' and the Y value in the YBC data is as follows:

[0022] a i =l i-1 +Y i +l i

[0023]

[0024] Among them, Y i θ is the bend feed length given in the YBC data. iLet be the angle between the i-th straight segment and the (i+1)-th straight segment of the bend.

[0025] The expression for the transformation matrix T is as follows:

[0026]

[0027] Where C is the cosine function COS, S is the sine function SIN, and α i-1 With θ i-1 These are the values ​​of the (i-1)th torsion angle and the joint angle, respectively.

[0028] The extraction of the XYZ data to be obtained is as follows: extract the 3×1 matrix from the upper right corner of the transformation matrix. The value is the XYZ data we are looking for.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] First, the calculation steps of this invention are simple and the computational workload is small. The calculation process does not require calculating the coordinates of the beginning and end points of the line segment; instead, it directly calculates the required XYZ coordinates without any intermediate solution steps. Furthermore, the calculation involves only one formula for multiplying multiple matrices, resulting in a relatively small computational load.

[0031] Second, the calculation results of this invention are highly accurate. Because the calculation steps are simple, it does not amplify the errors caused by inaccurate YBC data in the early stages. Attached Figure Description

[0032] Figure 1 Flowchart of the present invention;

[0033] Figure 2 A schematic diagram illustrating the relationship between parameter a and data Y in this invention. Detailed Implementation

[0034] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0036] See attached document Figure 1The specific implementation steps of the present invention are as follows:

[0037] (1) Insert data (0,0,0) at the beginning of the YBC dataset to make the known YBC dataset consistent with the XYZ dataset to be obtained in terms of the number of elements. This data simulates the origin of the base coordinate system of the robotic arm.

[0038] (2) Divide the bend into straight segments and curved segments. Based on the similarity between the bend structure and the robotic arm structure, the bend structure is equivalent to the robotic arm structure. Specifically, this includes: Equating the bend structure to the robotic arm structure means: using the segmentation principle and local geometric characteristics of the bend TRIZ theory to divide the straight segments and curved segments of the bend, equating the straight segments to the links of the robotic arm, and equating the curved segments to the joints of the robotic arm.

[0039] (3) Convert the known YBC data into the DH parameter data to be obtained.

[0040] (3a) When the pipe bending is equivalent to a robotic arm, the feed direction of the pipe bending machine is always the Y-axis direction, and the value of the offset d in the DH parameter is always 0.

[0041] (3b) is when the bent pipe is equivalent to a robotic arm, the rotation angle B value in the YBC data is equivalent to the joint angle θ value in the DH parameters, and the bending angle C value in the YBC data is equivalent to the twist angle α value in the DH parameters.

[0042] (3c) When the bent pipe is equated to a robotic arm, the value of the link length 'a' in the DH parameters can be calculated using the Y value in the YBC data. (See attached diagram.) Figure 2 In the DH parameters, the link length a i The value of Y in YBC data i The relationship between the values ​​is as follows:

[0043] a i =l i-1 +Y i +l i

[0044]

[0045] Among them, l i Y is the projection of the curved segment of the pipe in the feed direction. i θ is the bend feed length given in the YBC data. i Y is the i-th straight segment of the bend. i The normal vector and the (i+1)th line segment Y i+1 The angle between the normal vectors;

[0046] (4) Based on the link transformation theory of the robotic arm, n transformation matrices are obtained. The transformation matrix form is:

[0047]

[0048] in, Let α be the transformation matrix from the (i-1)th axis coordinate system to the ith axis coordinate system. i-1 For the (i-1)th twist angle, a i-1 Let θ be the length of the (i-1)th link. i Let d be the i-th joint angle. i As a bias, it is always 0 here. Rot(x,α) i-1 ) represents rotation about the x-axis. i-1 Trans(x,a) i-1 ) indicates a translation along the x-axis. i-1 Rot(z,θ) i ) represents a rotation θ around the z-axis i Trans(z,d) i ) indicates a translation d along the z-axis i .

[0049] The expression for the transformation matrix T is as follows:

[0050]

[0051] Where C is the cosine function COS and S is the sine function SIN.

[0052] (5) Extract XYZ data from the transformation matrix. The transformation matrix can be decomposed into a 3×1 matrix in the upper right corner. The value is the XYZ data we are looking for.

[0053] The above embodiments are only for illustrating the technical concept and features of the present invention and should not be construed as limiting the scope of protection of the present invention. All equivalent variations and modifications made within the scope of the claims of this invention should be considered within the scope of this invention.

Claims

1. A method for converting pipe bending data format YBC to XYZ, comprising the following steps: Step 1: Imput data to make the element data of the YBC dataset consistent with that of the XYZ dataset; Step 2: Divide the pipe bend to be determined into straight segments and curved segments, and convert the pipe bend structure into a robotic arm structure based on structural similarity. Step 3: Establish the parameter correspondence for converting YBC data to DH data; Step 4: Process the DH data based on the transformation matrix T of the robotic arm link transformation theory; Step 5: Extract the XYZ data to be obtained from the transformation matrix.

2. The method for converting pipe bending data format YBC to XYZ according to claim 1, characterized in that, The interpolated data is data (0,0,0) inserted at the beginning of the YBC dataset.

3. The method for converting pipe bending data format YBC to XYZ according to claim 1, characterized in that, The division of the bend into straight and curved segments refers to dividing the bend into straight and curved segments based on the segmentation principles and local geometric characteristics of the TRIZ theory of bends.

4. The method for converting pipe bending data format YBC to XYZ according to claim 1, characterized in that, The method of equating the bent pipe structure with a robotic arm structure includes: equating the straight segment with the connecting rod of the robotic arm, and equating the bent segment with the joint of the robotic arm.

5. The method for converting pipe bending data format YBC to XYZ according to claim 1, characterized in that, The parameter correspondence for the conversion of YBC data to DH data includes: Step 3a) Set the feed direction of the pipe bending machine to the Y-axis direction, and set the offset in the DH parameter. The value is 0; Step 3b) The rotation angle B value in the YBC data is equal to the joint angle in the DH parameter. The value of the bending angle C is equal to the twist angle in the DH parameter. value; Step 3c) Link length in DH parameters The relationship between the value and the Y value in the YBC data.

6. The method for converting pipe bending data format YBC to XYZ according to claim 5, characterized in that, The length of the link The relationship between the value and the Y value in the YBC data is as follows: ； ； in, Given the bend feed length in the YBC data. For the bend The nth straight segment and the nth The angle between line segments Where is the bending radius, These are all intermediate values ​​used to calculate the XYZ parameters.

7. The method for converting pipe bending data format YBC to XYZ according to claim 1, characterized in that, The expression for the transformation matrix T is as follows: ； in, Let S be the cosine function COS, and S be the sine function SIN. and The first The values ​​of the twist angle and the joint angle, For bias.

8. The method for converting pipe bending data format YBC to XYZ according to claim 7, characterized in that, The extraction of the XYZ data to be obtained is as follows: extract the upper right corner of the transformation matrix. 1-th order matrix The value is the XYZ data we are looking for.

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