Mobile additive manufacturing and repairing method and system

Abstract

The invention discloses a mobile additive manufacturing and repairing method and system, and relates to the technical field of large part manufacturing or repairing, the technical scheme is characterized in that preprocessed point cloud data of a to-be-manufactured surface are obtained, and the preprocessed point cloud data of the to-be-manufactured surface comprise point cloud edge data; fitting a plane equation of the to-be-manufactured surface, obtaining position information of a welding gun machining center, and calculating the height from the welding gun machining center to the to-be-manufactured plane; extracting the point cloud edge data, measuring an arc, fitting a space straight line, and obtaining the size and geometric information of the to-be-processed surface; a coordinate system is established on the surface to be machined, and the coordinate system of the surface to be machined is converted into a manufacturing system coordinate system; and a manufacturing track path is planned according to the obtained surface, a manufacturing track is generated, and then a system is started to start machining according to the manufacturing track. The space limitation of traditional fixed manufacturing equipment is broken through, and the problem that the vehicle body carrier is low in moving and positioning precision is solved.

Description

Technical Field

[0001] This invention relates to the field of manufacturing or repair technology for large components, and more specifically, to a mobile additive manufacturing and repair method and system. Background Technology

[0002] Metal additive manufacturing is an advanced manufacturing technology that creates three-dimensional metal parts by adding materials layer by layer. It primarily includes arc additive manufacturing and powder bed fusion, using computer-aided design models to control the deposition path for precise shaping. The advantages of this technology include high design freedom, the ability to produce complex geometries, high material utilization, suitability for manufacturing large components, and the ability to optimize material properties. Its applications are broad, covering aerospace, automotive, energy equipment, and medical implants, with particularly great potential in customized high-performance metal parts and sustainable manufacturing.

[0003] Conventional metal additive manufacturing equipment, due to its inherent structural dimensions, struggles to process or repair large structural components exceeding its own size. Manufacturing or repairing larger components typically requires a larger worktable and a greater range of motion, which undoubtedly increases the size and cost of the additive manufacturing equipment. Furthermore, once installed, large equipment is difficult to move, failing to meet the needs of manufacturing or repairing large outdoor components.

[0004] Chinese invention patent application CN114407354A discloses a multi-degree-of-freedom dual-nozzle tracked mobile 3D printing device, such as... Figure 1 As shown, the device uses a three-free robotic arm mounted on a tracked vehicle base to control two 3D printing nozzle assemblies for manufacturing. While this device overcomes spatial limitations in terms of movement range and theoretically can manufacture large parts, the track movement results in low positioning and motion accuracy, and the lack of other auxiliary positioning methods leads to low manufacturing precision or even manufacturing failure. Furthermore, the patent does not further consider the power supply issue, which also limits its manufacturing scope.

[0005] Chinese invention patent application CN109500978A discloses a mobile 3D printing vehicle for cement-based materials, such as... Figure 2 As shown, the vehicle uses a tracked chassis equipped with a robotic arm to control an extrusion system for additive manufacturing (3D printing) of cement materials. This approach also utilizes high-definition cameras and laser positioning sensors for positioning, improving manufacturing accuracy. However, this method is suitable for additive manufacturing of cement-based materials and cannot produce high-precision metal parts.

[0006] Chinese utility model patent application CN219988482U discloses a mobile additive manufacturing device, as shown in Figure 3. This device uses an omnidirectional, three-wheeled chassis to mount an extrusion unit controlled by three free robotic arms, enabling additive manufacturing without distance limitations. While this device overcomes the limitations of travel distance, the wheeled movement reduces positioning accuracy, leading to low manufacturing precision or even manufacturing failure. Furthermore, this patent does not address the power supply issue.

[0007] The above methods all employ a mobile vehicle-mounted robotic arm to control the print head for additive manufacturing. However, the following problems remain: First, manufacturing stability is not considered; the movement of the robotic arm on the ground can cause positional shifts, leading to manufacturing errors. Second, a positioning method is lacking. While patent CN109500978A proposes using laser positioning sensors and high-definition cameras for positioning, it does not provide specific methods. Third, the manufacturing materials mentioned are non-metallic, and no methods for manufacturing large metal materials are covered. Fourth, manufacturing during vehicle movement can introduce significant errors due to the vehicle's own motion, and the patent currently does not provide a solution.

[0008] In summary, current technologies cannot achieve additive manufacturing or repair of large-size metal parts. Therefore, this invention proposes a mobile additive manufacturing and repair method and system, which solves the problem of manufacturing or repairing large-size metal structural parts. Summary of the Invention

[0009] The above-mentioned technical objective of the present invention is achieved through the following technical solution: The first aspect of this invention provides a mobile additive manufacturing and repair method, comprising the following steps: Obtain preprocessed point cloud data of the surface to be manufactured, wherein the preprocessed point cloud data of the surface to be manufactured includes point cloud edge data; Fit the plane equation of the surface to be manufactured, obtain the position information of the welding gun machining center, and calculate the height of the welding gun machining center from the surface to be manufactured. Extract the edge data of the point cloud, measure the arc, fit the spatial straight line, and obtain the size and geometric information of the surface to be processed; Establish a coordinate system on the surface to be processed, transform the coordinate system of the surface to be processed into the coordinate system of the manufacturing system, and obtain the precise relative position of the surface to be manufactured and the manufacturing system in the coordinate system of the manufacturing system, as well as the information of the surface to be manufactured. The manufacturing trajectory path is planned based on the obtained surface, the manufacturing trajectory is generated, and then the system is started to begin processing according to the manufacturing trajectory.

[0010] In conjunction with the first aspect, the present invention is further configured such that: the plane equation of the surface to be manufactured is fitted using the least squares method. ; in, , , and It is the fitted position of the plane to be processed during the i-th manufacturing process.

[0011] In conjunction with the first aspect, the present invention is further configured such that: the method for calculating the height of the welding torch machining center from the plane to be manufactured is as follows: ; in, , , It is the location of the machining center for the welding torch.

[0012] In conjunction with the first aspect, the present invention is further configured such that: the extraction of point cloud edge data adopts the Alphashapes algorithm; the measurement of the arc adopts the spatial arc fitting method of Lagrange multiplier method; and the fitting of the spatial straight line adopts the least squares method.

[0013] In conjunction with the first aspect, the present invention is further configured such that: the method for transforming the coordinate system of the surface to be processed into the coordinate system of the manufacturing system is as follows: Find several feature points in the coordinate system of the surface to be processed. , ... Its coordinates on the workpiece are , ··· Then, the corresponding feature points are found in the scanned point cloud. The laser scanning sensor is fixed to the end of the robotic arm, and the coordinate system of the surface to be processed is { S} and manufacturing system coordinate system { T The relationship between them is definite, and their coordinate system in the manufacturing system is: , ... This allows you to find the corresponding feature points in the laser scanner. , ... To determine, that is: ; in, and These are the rotation and translation matrices for transforming the laser scanner coordinate system to the manufacturing system coordinate system, and these matrices are fixed. Then, based on the known feature points and the following transformation relationships, the transformation relationship from the workpiece coordinate system to the manufacturing system coordinate system can be determined: .

[0014] In conjunction with the first aspect, the present invention is further configured such that: the acquisition of preprocessed point cloud data of the surface to be manufactured includes scanning the surface to be manufactured using a line laser sensor to obtain point cloud data of the surface to be manufactured, and filtering the point cloud data of the surface to be manufactured to obtain preprocessed point cloud data of the surface to be manufactured.

[0015] In conjunction with the first aspect, the present invention is further configured such that: the filtering process of the point cloud data of the surface to be manufactured includes limiting the range of the point cloud by passing through filtering, then using statistical filtering and radius filtering to filter out Gaussian noise and outlier noise, and finally using the uniform voxel method to simplify the filtered point cloud data.

[0016] A second aspect of the present invention also provides a mobile additive manufacturing and repair apparatus / device / system, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the above method.

[0017] A third aspect of the present invention also provides a computer-readable storage medium having a computer program / instructions stored thereon, which, when executed by a processor, implement the steps of the above-described method.

[0018] A fourth aspect of the present invention also provides a computer program product, including a computer program / instructions that, when executed by a processor, implement the steps of the above-described method.

[0019] In summary, the present invention has the following beneficial effects: 1. By using automated guided vehicles (AGVs) equipped with additive manufacturing systems, the size limitations of traditional fixed manufacturing systems can be overcome, thereby enabling the manufacture or repair of large-sized parts; 2. To address the issue of insufficient positioning accuracy of automated guided vehicles (AGVs), a line laser sensor is used to achieve high-precision positioning of the workpiece and the manufacturing system. Additionally, outriggers are installed on the AGV to maintain stability during the manufacturing process. Furthermore, when manufacturing is completed at one position and the AGV moves to the next, the laser sensor can obtain the precise positional relationship between the current and next positions, thereby achieving high-precision continuous manufacturing and ensuring the stability of manufacturing large-sized parts. Attached Figure Description

[0020] Figure 1 This invention relates to a multi-degree-of-freedom dual-nozzle tracked mobile 3D printing device. Figure 2 This invention relates to a mobile 3D printing vehicle for cement-based materials, as described in the background section of the present invention. Figure 3 This is a mobile additive manufacturing device in the background art of this invention; Figure 4 It is the mobile additive manufacturing equipment in Embodiment 1 of the present invention; Figure 5 This refers to the mobile additive manufacturing process in Embodiment 1 of the present invention; Figure 6 This is the process of acquiring surface data to be manufactured using a line laser sensor in Embodiment 1 of the present invention.

[0021] In the diagram: 1. Outrigger; 2. Automated Guided Vehicle; 3. Wire; 4. Six-DOF robotic arm; 5. Line laser sensor; 6. Welding torch; 7. Wire feeder; 8. Power supply; 9. Shielding gas; 10. Trailer. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1: The mobile additive manufacturing equipment used in this method, such as... Figure 4 As shown, the automated guided vehicle (AGV), equipped with a six-degree-of-freedom (DOF) robotic arm, moves to the location requiring manufacturing or repair. The AGV's outriggers lower to ensure stability throughout the manufacturing process, preventing displacement and guaranteeing manufacturing accuracy. Simultaneously, the positive terminal of the welding power supply mounted on the trailer is connected to the workpiece and grounded along with it. Then, a line laser sensor mounted on the six-DOF robotic arm scans the surface to be manufactured or repaired, acquiring surface data and establishing a relative coordinate system. The system generates a manufacturing path based on the surface data. Then, the protective gas and heat source mounted on the trailer, as well as the wire feeder mounted on the six-DOF robotic arm, are activated. The wire on the six-DOF robotic arm is fed into the welding torch by the wire feeder. The six-DOF robotic arm drives the welding torch to begin manufacturing or repairing along the planned path. Once manufacturing or repair is completed at one location, the system moves to the next location and repeats the process, enabling the manufacturing or repair of ultra-large workpieces. Multiple mobile additive manufacturing devices can also be used simultaneously to improve manufacturing efficiency.

[0024] Unlike existing additive manufacturing methods, this method utilizes an automated guided vehicle (AGV) carrying the additive manufacturing system for movement. A challenge lies in the low positioning accuracy of the AGV, which struggles to meet the precision requirements of manufacturing or repair. Therefore, after the AGV reaches the manufacturing position, its outriggers lower to fix the entire manufacturing system in place. A line laser sensor then scans the surface to be manufactured, acquiring surface data, identifying the surface morphology, and establishing a relative coordinate system on the surface. Based on the surface data and coordinates, a manufacturing trajectory is generated, and manufacturing begins. After the current manufacturing is completed, when the AGV moves to the next station with the additive manufacturing system, the line laser-scanned area needs to partially overlap with the previously scanned area. Through surface data matching, the positional relationship between the currently scanned area and the previously scanned area is established. Then, a manufacturing path is generated manually or by the system, and manufacturing continues. The manufacturing process is shown in Figure 5.

[0025] The surface data to be manufactured includes both height and planar dimensions. First, a line laser sensor is used to scan the surface to be manufactured, acquiring point cloud data. Then, the point cloud is filtered, and the height data of the planar surface is obtained through background fitting. Finally, the planar dimensions are calculated through edge extraction. The process of acquiring surface data using a line laser sensor is shown in Figure 6.

[0026] Specifically, a mobile additive manufacturing and repair method includes the following steps: S100. Obtain preprocessed point cloud data of the surface to be manufactured, wherein the preprocessed point cloud data of the surface to be manufactured includes point cloud edge data; S200. Fit the plane equation of the surface to be manufactured, obtain the position information of the welding gun machining center, and calculate the height of the welding gun machining center from the surface to be manufactured; S300. Extract point cloud edge data, measure arcs, fit spatial straight lines, and obtain the dimensions and geometric information of the surface to be processed; S400. Establish a coordinate system on the surface to be processed, transform the coordinate system of the surface to be processed into the coordinate system of the manufacturing system, and obtain the precise relative position of the surface to be manufactured and the manufacturing system in the coordinate system of the manufacturing system, as well as the information of the surface to be manufactured. S500. Obtain the cross-sectional information of the part to be manufactured, plan the manufacturing trajectory path based on the geometric information of the surface to be processed and the cross-sectional information of the part to be manufactured, generate the manufacturing trajectory, and then start the system to start processing according to the manufacturing trajectory.

[0027] In step S100 of this embodiment, obtaining preprocessed point cloud data of the surface to be manufactured includes scanning the surface to be manufactured using a line laser sensor to obtain point cloud data of the surface to be manufactured, and filtering the point cloud data of the surface to be manufactured to obtain preprocessed point cloud data of the surface to be manufactured.

[0028] The filtering process for the point cloud data of the surface to be manufactured includes limiting the range of the point cloud through pass-through filtering, then using statistical filtering and radius filtering to filter out Gaussian noise and outlier noise, and finally using the uniform voxel method to simplify the filtered point cloud data.

[0029] In step S200 of this embodiment, the plane equation of the surface to be manufactured is fitted using the least squares method: ; in, , , and It is the fitted position of the plane to be processed during the i-th manufacturing process.

[0030] The method for calculating the height from the welding torch machining center to the surface to be manufactured is as follows: ; in, , , It is the location of the machining center for the welding torch.

[0031] In step S300 of this embodiment, the extraction of point cloud edge data is performed using the Alpha shapes algorithm; the measurement of the arc is performed using the spatial arc fitting method of the Lagrange multiplier method; and the fitting of the spatial straight line is performed using the least squares method.

[0032] By using the height of the welding torch machining center from the surface to be manufactured, and the dimensions and geometric information of the surface to be manufactured, the position of the welding torch relative to the surface to be manufactured is determined, in order to establish the coordinate system of the surface to be manufactured and define its boundaries.

[0033] In step S400 of this embodiment, the method for transforming the coordinate system of the surface to be processed into the coordinate system of the manufacturing system is as follows: Find several feature points in the coordinate system of the surface to be processed. , ... Its coordinates on the workpiece are , ··· Then, the corresponding feature points are found in the scanned point cloud. The laser scanning sensor is fixed to the end of the robotic arm, and the coordinate system of the surface to be processed is { S} and manufacturing system coordinate system { T The relationship between them is definite, and their coordinate system in the manufacturing system is: , ... This allows you to find the corresponding feature points in the laser scanner. , ... To determine, that is: ; in, and These are the rotation and translation matrices for transforming the laser scanner coordinate system to the manufacturing system coordinate system, and these matrices are fixed. Then, based on the known feature points and the following transformation relationships, the transformation relationship from the workpiece coordinate system to the manufacturing system coordinate system can be determined: .

[0034] In step S500 of this embodiment, the manufacturing trajectory path is planned, and the manufacturing trajectory is generated as follows: for simple shapes, the trajectory can be planned manually or automatically generated by an algorithm; for complex shapes, the trajectory is automatically generated by an algorithm, commonly the contour offset method, which uses the geometric information of the surface to be processed and the cross-sectional information of the part to be manufactured to generate a filling path (such as Zigzag, unidirectional scanning), i.e., the manufacturing trajectory. The input is the surface information to be processed and the cross-sectional shape of the part to be manufactured; the output is the motion command of the robotic arm, such as G-code.

[0035] Example 2: The present invention also provides an apparatus / device / system for a mobile additive manufacturing and repair method and system, comprising a memory, a processor, and a computer program stored in the memory, characterized in that the processor executes the computer program to implement the steps of the above method.

[0036] The present invention also provides a computer-readable storage medium having a computer program / instructions stored thereon, which, when executed by a processor, implement the steps of the above-described method.

[0037] The present invention also provides a computer program product, including a computer program / instructions that, when executed by a processor, implement the steps of the above-described method.

[0038] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A mobile additive manufacturing and repair method, characterized in that: Includes the following steps: Obtain preprocessed point cloud data of the surface to be manufactured, wherein the preprocessed point cloud data of the surface to be manufactured includes point cloud edge data; Fit the plane equation of the surface to be manufactured, obtain the position information of the welding gun machining center, and calculate the height of the welding gun machining center from the surface to be manufactured. Extract the edge data of the point cloud, measure the arc, fit the spatial straight line, and obtain the size and geometric information of the surface to be processed; Establish a coordinate system on the surface to be processed, transform the coordinate system of the surface to be processed into the coordinate system of the manufacturing system, and obtain the precise relative position of the surface to be manufactured and the manufacturing system in the coordinate system of the manufacturing system, as well as the information of the surface to be manufactured. Based on the acquired surface information and the cross-sectional information of the part to be manufactured, the manufacturing trajectory path is planned, the manufacturing trajectory is generated, and then the system is started to begin processing according to the manufacturing trajectory.

2. The mobile additive manufacturing and repair method and system according to claim 1, characterized in that: The process of acquiring preprocessed point cloud data of the surface to be manufactured includes scanning the surface to be manufactured using a line laser sensor to obtain point cloud data of the surface to be manufactured, and filtering the point cloud data of the surface to be manufactured to obtain preprocessed point cloud data of the surface to be manufactured.

3. The mobile additive manufacturing and repair method and system according to claim 2, characterized in that: The filtering process for the point cloud data of the surface to be manufactured includes limiting the range of the point cloud through pass-through filtering, then using statistical filtering and radius filtering to filter out Gaussian noise and outlier noise, and finally using the uniform voxel method to simplify the filtered point cloud data.

4. The mobile additive manufacturing and repair method and system according to claim 1, characterized in that: The plane equation of the surface to be manufactured is obtained by fitting the plane equation of the surface to be manufactured using the least squares method: ； in, , , and It is the fitted position of the plane to be processed during the i-th manufacturing process.

5. The mobile additive manufacturing and repair method according to claim 4, characterized in that: The method for calculating the height from the welding torch machining center to the surface to be manufactured is as follows: ； in, , , It is the location of the machining center for the welding torch.

6. The mobile additive manufacturing and repair method according to claim 1, characterized in that: The extraction of point cloud edge data uses the Alpha shapes algorithm; the measurement of the arc uses the spatial arc fitting method of the Lagrange multiplier method; and the fitting of the spatial straight line uses the least squares method.

7. The mobile additive manufacturing and repair method according to claim 1, characterized in that: The method for transforming the coordinate system of the surface to be processed into the coordinate system of the manufacturing system is as follows: Find several feature points in the coordinate system of the surface to be processed. , ... Its coordinates on the workpiece are , ··· Then, the corresponding feature points are found in the scanned point cloud. The laser scanning sensor is fixed to the end of the robotic arm, and the coordinate system of the surface to be processed is { S } and manufacturing system coordinate system { T The relationship between them is definite, and their coordinate system in the manufacturing system is: , ... This allows you to find the corresponding feature points in the laser scanner. , ... To determine, that is: ； in, and These are the rotation and translation matrices for transforming the laser scanner coordinate system to the manufacturing system coordinate system, and these matrices are fixed. Then, based on the known feature points and the following transformation relationships, the transformation relationship from the workpiece coordinate system to the manufacturing system coordinate system can be determined: 。 8. An apparatus / device / system for a mobile additive manufacturing and repair method and system, comprising a memory, a processor, and a computer program stored in the memory, characterized in that, The processor executes the computer program to implement the steps of the method according to any one of claims 1-7.

9. A computer-readable storage medium having a computer program / instructions stored thereon, characterized in that, When the computer program / instructions are executed by the processor, they implement the steps of the method described in any one of claims 1-7.

10. A computer program product comprising a computer program / instructions, characterized in that, When the computer program / instructions are executed by the processor, they implement the steps of the method described in any one of claims 1-7.

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