A method for realizing automatic assembly of differentiated parts based on virtual design

Abstract

The present invention belongs to the field of automated assembly, and specifically is a method for implementing differentiated automatic assembly of parts based on virtual design, comprising the following steps: measuring the part to obtain the coordinates of the key points of the part and the current position of the robot gripper; building a model of the part and the assembly using Solidworks; connecting the assembly end of part 2 to the model of assembly part 3, and determining the spatial position of part 1 relative to part 2 based on the matching relationship between parts 1 and 2; creating a model of assembly part 3, and determining the processing dimensions of assembly part 3 based on the model of assembly part 3; obtaining the position of the gripper in the robot coordinate system; and finally guiding the gripper and part 1 to the assembly position of assembly part 3 to complete the assembly. The method of the present invention has high positioning accuracy for key point coordinates and is easy to operate, can realize large-scale automatic assembly, and solves the problems of low efficiency of current technology and inaccurate manual measurement.

Description

Technical Field

[0001] The invention belongs to the field of automatic assembly, in particular to a method for realizing automatic assembly of differentiated parts based on virtual design. Background Art

[0002] With the development of the economy and society, a new generation of consumers, driven by their pursuit of freedom and individuality, enjoys increasing privileges. Standardization is being replaced by customization, ushering in a new era of industrial production. Consequently, the manufacturing process often encounters the problem of inconsistent product shape features. This is particularly true in the field of automated assembly, where inconsistent product geometry is a bottleneck restricting the automation of the assembly process. Due to the poor consistency of welded parts, the connectors of each product vary, making robotic assembly impossible. The current production method involves manually placing the workpiece in the assembly position, measuring it with a laser tracker, and then manually adjusting the position based on the measured values. This is inefficient, labor-intensive, and significantly impacts product quality due to the worker's operating habits. Therefore, it is crucial to propose a method to address this issue when the consistency of assembled parts cannot be guaranteed and achieve automated assembly. Summary of the Invention

[0003] The purpose of the present invention is to provide an intelligent lithium-ion battery management system for electric vehicles with stable performance, small size, low cost and low power consumption, so as to overcome the defects of the above-mentioned battery management systems.

[0004] The technical solution adopted by the present invention to achieve the above-mentioned purpose is: a method for realizing automatic assembly of differentiated parts, characterized by comprising the following steps:

[0005] 1) Measure parts 1 and 2, obtain the key point coordinates of parts 1 and 2 based on the robot coordinate system, and obtain the current position of the robot gripper based on the gripper coordinate system;

[0006] 2) Based on the key point coordinates of Part 1 and Part 2 in the robot coordinate system, create the Part 1 model, Part 2 model, and the assembly Part 3 model using Solidworks;

[0007] 3) Connect the assembly end of part 2 to the model of assembly part 3, and align the coordinate system of part 2 with the coordinate system of assembly part 3; determine the spatial position of part 1 relative to part 2 based on the matching relationship between parts 1 and 2;

[0008] 4) Read the model of assembly part 3, create a model of assembly part 3 based on the spatial position of part 1 relative to part 2, and determine the processing size of assembly part 3 based on the model of assembly part 3;

[0009] 5) Get the position of the gripper in the robot coordinate system;

[0010] 6) Based on the spatial position of part 1 relative to part 2 in step 3) and the machining dimensions of assembly part 3 in step 4), guide the clamp and part 1 to the assembly position of assembly part 3 to complete the assembly.

[0011] The step 1) is specifically as follows:

[0012] 1-1) The robot clamps the pipe bending three-dimensional coordinate measuring machine to measure the part 1, and obtains the key point coordinates of the key points of the part 1 based on the coordinate system of the pipe bending three-dimensional coordinate measuring machine;

[0013] 1-2) Performing coordinate transformation on the key points of part 1 based on the coordinate system of the pipe bending coordinate measuring machine to transform the key points of part 1 to the coordinates of the key points of part 1 based on the robot coordinate system;

[0014] 1-3) The robot reads the end flange pose of the robot, obtains the end flange pose information, and converts the pose information into the key point coordinates bound to the gripper, which is used to represent the current position of the robot gripper based on the gripper coordinate system;

[0015] 1-4) Fix part 2 on the assembly station so that the measurement coordinate system of part 2 is consistent with the robot coordinate system, and measure part 2 using a line laser measuring instrument to obtain the position of the key points of part 2 in the robot coordinate system.

[0016] The key points include:

[0017] Select the key points P3 and P7 at the ends of the straight pipes of Part 1 and Part 2;

[0018] Select the key points P6 and P11 at the end of the elbow of part 1 and part 2;

[0019] Select the key points P4 and P8 at the junction of the straight pipe and the curved pipe of Part 1 and Part 2;

[0020] Select the assembly end key points P5 and P12 of part 1 and part 2;

[0021] The corresponding remaining straight pipes or curved pipes of Part 1 and Part 2 are selected as key points P1, P2, P9, and P10.

[0022] Step 3) determining the spatial position of part 1 relative to part 2 based on the matching relationship includes the following steps:

[0023] 3-1) Set line segment p3p4 of part 1 to be parallel to line segment p7p8 of part 2; set the distance between line segment p3p4 and line segment p7p8 to be L2;

[0024] 3-2) Perform a cross product operation on line segment p3p4 of part 1 and line segment p1p2, and translate line segment p3p4 along the cross product result to obtain the spatial position of p7p8. At this time, the distance between p1 and P9 is L1; the spatial position of part 1 is obtained, and then the relative position relationship of part 1 with respect to part 2 is determined.

[0025] The step 4) is specifically as follows:

[0026] 4-1) Set vector 1 pointing from p5 to p6 and vector 2 pointing from p12 to p11; obtain the distance L3 between p5 and p12, and the length of assembly part 3;

[0027] 4-2) The assembly is modeled based on vector 1, vector 2, and distance L3, combined with the shape information of the assembly, to obtain a model of the final assembly part 3.

[0028] The step 5) comprises the following steps:

[0029] 5-1) Based on the spatial position of part 1 relative to part 2 and the pose information of the robot end flange, obtain the coordinates of the key points of the binding of the grippers R1, R2, and R3 at this time;

[0030] Among them, R1 is the center of the gripper coordinate system, R2 is a point in the x direction, and R3 is a point in the z direction;

[0031] 5-2) Obtain the y-direction vector by cross-producting the x-direction vector and the z-direction vector; that is, obtain the coordinates (XB, YB, ZB) of the gripper based on the gripper coordinate system;

[0032] 5-3) Obtain the rotation matrix between the gripper coordinate system and the robot coordinate system;

[0033] 5-4) Convert the rotation matrix into the robot identification matrix and obtain the position of the gripper in the robot coordinate system;

[0034] 5-5) Based on the obtained position of the gripper in the robot coordinate system, guide the gripper and part 1 to the assembly position.

[0035] The step 5-3) is specifically as follows:

[0036] The rotation matrix between the gripper coordinate system and the robot coordinate system:

[0037]

[0038] in, is the unit vector of the principal axis direction of the B coordinate system in the A coordinate system, is the principal axis direction of the A coordinate system.

[0039] In step 5-4), the rotation matrix is converted into a robot recognition matrix, specifically:

[0040] The TCP coordinates of an industrial robot are usually represented by a position coordinate and three angle values, namely X, Y, Z, α, β, and γ;

[0041] That is, the robot recognition matrix:

[0042]

[0043] Among them, α is the rotation angle around the Z axis, β is the rotation angle around the Y axis, γ is the rotation angle around the X axis, and s and c are the transformation parameters of the recognition matrix.

[0044] The coordinate values of α, β, and γ are obtained through the robot identification matrix, and the coordinate values of R1 are (X, Y, Z), that is, the position of the gripper in the robot coordinate system is (X, Y, Z, α, β, γ).

[0045] The present invention has the following beneficial effects and advantages:

[0046] 1. The method of the present invention has high positioning accuracy for key point coordinates and is easy to operate, which can realize large-scale automatic assembly and solve the problems of low efficiency of current technology and inaccurate manual measurement.

[0047] 2. The method of the present invention establishes a model of the assembly part 3 based on the relative positional relationship between the parts 1 and 2 by modeling the relationship between the parts 1 and 2, and can achieve perfect fit between the parts 1 and 2 by processing the model of the assembly part 3.

[0048] 3. The method of this application can be applied to the automatic assembly of any differentiated parts, solving the problem of being unable to quickly mass-produce due to different assembly ports. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a schematic diagram of the assembly of differentiated parts of the present invention;

[0050] Figure 2 This is a diagram of the selection of key points before assembly of differentiated parts of the present invention;

[0051] Figure 3 It is a three-dimensional schematic diagram of the assembly part 3 of the present invention. DETAILED DESCRIPTION

[0052] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0053] This embodiment assumes an application scenario that is widely present in the production process of a factory. Figure 1As shown, it is a schematic diagram of the differentiated parts assembly of the present invention. Part 1 and Part 2 need to be connected together, but they need to maintain a specific relative position relationship. In order to ensure the relative position relationship, it is inevitable that the connection position between Part 1 and Part 2 cannot be perfectly docked, so it is necessary to introduce assembly part 3 to achieve transfer.

[0054] The theoretical models for Parts 1 and 2 are identical. When assembled, Parts 1 and 2 must maintain their horizontal axes parallel, with a distance of L1 between them, and their vertical axes horizontal. In the theoretical model, the top interfaces of Parts 1 and 2 are coaxial, and Part 3 of the assembly is a standard cylindrical shape.

[0055] However, in actual production, the shapes of parts 1 and 2 are not standard. Therefore, while ensuring that the horizontal axis and the vertical axis are parallel to each other and the distance between the horizontal axes is L2, the top interface cannot be guaranteed to be coaxial. Therefore, assembly part 3 is not a standard cylindrical shape and its length is not a fixed value.

[0056] Therefore, a method for realizing automatic assembly of differentiated parts based on virtual design is designed to solve the above problems. The present invention comprises the following steps:

[0057] 1) Measure parts 1 and 2, obtain the key point coordinates of parts 1 and 2 based on the robot coordinate system, and obtain the current position of the robot gripper based on the gripper coordinate system;

[0058] 2) Based on the key point coordinates of Part 1 and Part 2 in the robot coordinate system, create the Part 1 model, Part 2 model, and the assembly Part 3 model using SolidWorks;

[0059] 3) Connect the assembly end of Part 2 to the model of Part 3 in the assembly, and align the coordinate system of Part 2 with the coordinate system of Part 3 in the assembly; determine the spatial position of Part 1 relative to Part 2 based on the matching relationship between Part 1 and Part 2;

[0060] 4) Read the model of assembly part 3, create a model of assembly part 3 based on the spatial position of part 1 relative to part 2, and determine the processing size of assembly part 3 based on the model of assembly part 3;

[0061] 5) Get the position of the gripper in the robot coordinate system;

[0062] 6) According to the spatial position of part 1 relative to part 2 in step 3) and the processing size of assembly part 3 in step 4), the clamp and part 1 are guided to the assembly position of assembly part 3 to complete the assembly.

[0063] like Figure 2As shown in the figure, it is a diagram of the selection of key points before the assembly of the differentiated parts of the present invention. The coordinates of the key points of parts 1 and 2 are measured using a measuring device. The key points are as follows: Figure 2 In this embodiment, part 1 is measured using a pipe bending measuring machine, and part 2 is measured using a line laser.

[0064] Part 1 is gripped by a robot and placed into the elbow measuring device for measurement. The measurement results are then transformed to sync with the robot's coordinate system. The robot's end flange pose at the measurement location is read and converted into three points, representing the current position of the robot's gripper. Part 2 is fixed to the assembly station during measurement, ensuring that the measurement coordinate system is consistent with the robot's.

[0065] Virtual Design of Adapters Based on Secondary Development of CAD Software

[0066] Select the key points P3 and P7 at the ends of the straight pipes of Part 1 and Part 2;

[0067] Select the key points P6 and P11 at the end of the elbow of part 1 and part 2;

[0068] Select the key points P4 and P8 at the junction of the straight pipe and the curved pipe of Part 1 and Part 2;

[0069] Select the assembly end key points P5 and P12 of part 1 and part 2;

[0070] The corresponding remaining straight pipes or curved pipes of Part 1 and Part 2 are selected as key points P1, P2, P9, and P10.

[0071] Create new parts in SolidWorks, create Part 1 and Part 2 respectively, then create a new assembly, insert Part 2, and overlap the coordinate system of Part 2 with the assembly coordinate system.

[0072] Add mates:

[0073] ① Line segment p3p4 is parallel to line segment p7p8;

[0074] ②The distance between line segment p3p4 and line segment p7p8 is L2;

[0075] ③ Calculate the cross product of p3p4 and p1p2, and translate p3p4 along the direction of the cross product result to obtain the spatial position of p7p8;

[0076] ④The distance between P1 and P9 is L1.

[0077] The spatial position of part 1 is determined by the above matching relationship, thereby determining the relative position relationship between part 1 and part 2.

[0078] Read the shape information of part 3:

[0079] ①P5 points to the vector in the direction of P6, and P12 points to the vector in the direction of P11;

[0080] ②The distance between P5 and P12.

[0081] With the above information, the model of part 3 can be created, such as Figure 3 As shown in the figure, the processing dimensions of part 3 can be obtained through the model to guide the processing.

[0082] The above step 5) includes the following steps:

[0083] 5-1) Based on the spatial position of part 1 relative to part 2 and the position information of the robot end flange, obtain the key point coordinates of the gripper R1, R2, and R3 at this time;

[0084] Among them, R1 is the center of the gripper coordinate system, R2 is a point in the x direction, and R3 is a point in the z direction;

[0085] 5-2) The y direction vector is obtained by cross-producting the x direction vector and the z direction vector; that is, the coordinates of the gripper based on the gripper coordinate system (X B , Y B , Z B );

[0086] 5-3) Obtain the rotation matrix between the gripper coordinate system and the robot coordinate system;

[0087] 5-4) Convert the rotation matrix into the robot identification matrix and obtain the position of the gripper in the robot coordinate system;

[0088] 5-5) Based on the obtained position of the gripper in the robot coordinate system, guide the gripper and part 1 to the assembly position.

[0089] The rotation matrix between the gripper coordinate system and the robot coordinate system is obtained by the following formula:

[0090]

[0091] in, is the unit vector of the principal axis direction of the B coordinate system in the A coordinate system, is the principal axis direction of the A coordinate system.

[0092] The rotation matrix is converted into the robot identification matrix and the position of the gripper in the robot coordinate system is obtained.

[0093] The TCP coordinates of an industrial robot are usually represented by a position coordinate and three angle values, namely X, Y, Z, α, β, and γ. α, β, and γ can be calculated using formulas (1) and (2), and X, Y, and Z are the coordinate values of R1.

[0094]

[0095] Among them, α is the rotation angle around the Z axis, β is the rotation angle around the Y axis, γ is the rotation angle around the X axis, and s and c are the transformation parameters of the recognition matrix.

[0096] The coordinate values of α, β, and γ are obtained through the robot identification matrix, and the coordinate values of R1 are (X, Y, Z), that is, the position of the gripper in the robot coordinate system is (X, Y, Z, α, β, γ).

[0097] The final position of the gripper can be obtained through the above calculations, and the gripper and part 1 can be guided to the assembly position.

[0098] The above description is only an embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modification, equivalent replacement, improvement, expansion, etc. made within the spirit and principle of the present invention are included in the scope of protection of the present invention.

Claims

1. A method for realizing automatic assembly of differentiated parts based on virtual design, characterized in that: The following steps are involved: 1) Measure parts 1 and 2, obtain the key point coordinates of parts 1 and 2 based on the robot coordinate system, and obtain the current position of the robot gripper based on the gripper coordinate system; 2) Based on the key point coordinates of Part 1 and Part 2 in the robot coordinate system, create the Part 1 model, Part 2 model, and the assembly Part 3 model using Solidworks; The key points include: Select the key points P3 and P7 at the ends of the straight pipes of Part 1 and Part 2; Select the key points P6 and P11 at the end of the elbow of part 1 and part 2; Select the key points P4 and P8 at the junction of the straight pipe and the curved pipe of Part 1 and Part 2; Select the assembly end key points P5 and P12 of part 1 and part 2; Select the corresponding other straight pipes or curved pipes of Part 1 and Part 2 as key points P1, P2, P9, and P10; 3) Connect the assembly end of part 2 to the model of assembly part 3, and align the coordinate system of part 2 with the coordinate system of assembly part 3; determine the spatial position of part 1 relative to part 2 based on the matching relationship between parts 1 and 2; Determining the spatial position of part 1 relative to part 2 based on the matching relationship includes the following steps: 3-1) setting the line segment p3p4 of part 1 to be parallel to the line segment p7p8 of part 2; setting the distance between the line segment p3p4 and the line segment p7p8 to be L2; 3-2) Perform a cross product operation on line segment p3p4 of part 1 and line segment p1p2, and translate line segment p3p4 along the cross product result to obtain the spatial position of p7p8. At this time, the distance between p1 and P9 is L1. The spatial position of part 1 is obtained, and the relative position relationship of part 1 with respect to part 2 is determined. 4) Read the model of assembly part 3, create a model of assembly part 3 based on the spatial position of part 1 relative to part 2, and determine the processing size of assembly part 3 based on the model of assembly part 3; 4-1) Set vector 1 pointing from p5 to p6 and vector 2 pointing from p12 to p11; obtain the distance L3 between p5 and p12, and the length of assembly part 3; 4-2) Modeling the assembly based on vector 1, vector 2, and distance L3, combined with the shape information of the assembly, to obtain a model of the final assembly part 3; 5) Get the position of the gripper in the robot coordinate system; 6) According to the spatial position of part 1 relative to part 2 in step 3) and the processing size of assembly part 3 in step 4), the clamp and part 1 are guided to the assembly position of assembly part 3 to complete the assembly.

2. The method for realizing automatic assembly of differentiated parts based on virtual design according to claim 1, characterized in that: The step 1) is specifically as follows: 1-1) The robot clamps the pipe bending three-dimensional coordinate measuring machine to measure the part 1, and obtains the key point coordinates of the key points of the part 1 based on the coordinate system of the pipe bending three-dimensional coordinate measuring machine; 1-2) Performing coordinate transformation on the key points of part 1 based on the coordinate system of the pipe bending coordinate measuring machine to transform the key point coordinates of part 1 based on the robot coordinate system; 1-3) The robot reads the end flange pose of the robot, obtains the end flange pose information, and converts the pose information into the key point coordinates bound to the gripper, which is used to represent the current position of the robot gripper based on the gripper coordinate system; 1-4) Fix part 2 on the assembly station so that the measurement coordinate system of part 2 is consistent with the robot coordinate system, and measure part 2 using a line laser measuring instrument to obtain the position of the key points of part 2 in the robot coordinate system.

3. The method for realizing automatic assembly of differentiated parts based on virtual design according to claim 1, characterized in that: The step 5) comprises the following steps: 5-1) Based on the spatial position of part 1 relative to part 2 and the pose information of the robot end flange, obtain the coordinates of the key points of the binding of the grippers R1, R2, and R3 at this time; Among them, R1 is the center of the gripper coordinate system, R2 is a point in the x direction, and R3 is a point in the z direction; 5-2) Obtain the y-direction vector by cross-producting the x-direction vector and the z-direction vector; that is, obtain the coordinates (XB, YB, ZB) of the gripper based on the gripper coordinate system; 5-3) Obtain the rotation matrix between the gripper coordinate system and the robot coordinate system; 5-4) Convert the rotation matrix into the robot identification matrix and obtain the position of the gripper in the robot coordinate system; 5-5) Based on the obtained position of the gripper in the robot coordinate system, guide the gripper and part 1 to the assembly position.

4. The method for realizing automatic assembly of differentiated parts based on virtual design according to claim 3, characterized in that: The step 5-3) is specifically as follows: The rotation matrix between the gripper coordinate system and the robot coordinate system: in, is the unit vector of the principal axis direction of the B coordinate system in the A coordinate system, is the principal axis direction of the A coordinate system.

5. The method for realizing automatic assembly of differentiated parts based on virtual design according to claim 4, characterized in that: In step 5-4), the rotation matrix is converted into a robot recognition matrix, specifically: The TCP coordinates of an industrial robot are usually represented by a position coordinate and three angle values, namely X, Y, Z, α, β, and γ; That is, the robot recognition matrix: Among them, α is the rotation angle around the Z axis, β is the rotation angle around the Y axis, and γ is the rotation angle around the X axis; The coordinate values of α, β, and γ are obtained through the robot identification matrix, and the coordinate values of R1 are (X, Y, Z), that is, the position of the gripper in the robot coordinate system is (X, Y, Z, α, β, γ).

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