Articulated robot sawing machine trajectory generation method

Abstract

This invention proposes a method for generating the trajectory of a sawing machine using a multi-jointed robotic arm. The method employs a multi-jointed robotic arm to expand the spatial degrees of freedom for machining the workpiece. When processing complex external contours with intersecting curves and straight lines, the method includes the following steps: Step 1: Read the DXF file of the part to obtain its external contour diagram; Step 2: Based on the contour graphic data, classify the contour data and select the machining contour; Step 3: Use an algorithm to classify and filter the machining contours, specifically: establish constraints based on the contour data, and generate a continuous, machinable trajectory for the contour through multiple constraints; Step 4: Process the machining contour sequentially, and finally generate a continuous machining path based on the data points discretized from the trajectory path. This invention can achieve machining automation and improve machining efficiency.

Description

Technical Field

[0001] This invention relates to the field of machining technology, and in particular to a method for generating the trajectory of a sawing machine using an articulated robotic arm. Background Technology

[0002] Currently, there are two main technologies for removing faucet gates. One is manual cutting, where the faucet is placed under a band saw blade and the gate is cut off manually. This method is extremely dangerous and cannot guarantee the standardization of the faucet during cutting, resulting in uneven parts that cause unnecessary trouble for the next process and reduce work efficiency. The second commonly used method is a two-axis band saw, which has X and Y axes and can only move up, down, left, and right. The workpiece is fixed and moved in a plane by the two axes of the machine tool, and the band saw blade processes it along a predetermined trajectory. However, due to the spatial physical characteristics of the band saw blade, some parts of the workpiece cannot be processed during the process. With the diversified design of faucets, the processing line for cutting the gate is no longer limited to a straight segment. Vertical band saws on the market generally use single-axis feeding, which has many limitations under this condition: the cutting line is limited to a straight line, the cutting range is fixed, and repeated clamping and positioning are required when processing multiple segments.

[0003] Traditional manual cutting is inefficient and dangerous, and clearly cannot keep up with production requirements. Furthermore, modern faucets come in a wide variety of designs and shapes, and the simple linear trajectories produced by traditional sawing machines can no longer meet market demands. Due to the physical characteristics of saw blades—they are blade-shaped and only have cutting capability on one side—they are constrained by the processing space once they enter the workpiece, making it difficult for traditional machine tools to achieve curved machining. Summary of the Invention

[0004] This invention proposes a method for generating the trajectory of an articulated robotic arm sawing machine, which can realize processing automation and improve processing efficiency.

[0005] The present invention adopts the following technical solution.

[0006] A method for generating the trajectory of a sawing machine with an articulated robotic arm, wherein the method employs a multi-jointed robotic arm to expand the spatial degree of freedom of the cutting tool in processing the workpiece, and when dealing with complex external contours where curves and straight lines meet, the method includes the following steps;

[0007] Step 1: Read the DXF file of the part to obtain the outer contour drawing of the part.

[0008] Step 2: Based on the contour graphic data, classify the contour data and select the contours to be processed;

[0009] Step 3: Classify and filter the processing contours using an algorithm. Specifically, based on the contour data, establish constraints and generate a continuous, processable trajectory for the contour using multiple constraints.

[0010] Step 4: Process along the machining contour sequentially, and generate a continuous machining path based on the data points discretized from the trajectory route.

[0011] The constraints in step three include: determining the machining contour type and style, determining whether the machining requirements are met, determining the machining direction, determining whether the machining requires repeated tool entry, and determining whether auxiliary machining is required.

[0012] In step three, the read contour data are arranged and categorized in order. By selecting the processing contour, the previous processing contour data and the next contour data are obtained. Furthermore, the upper and lower boundary data connected to the processing contour are obtained, and it is determined whether they are straight lines or curves.

[0013] Step three includes the following steps;

[0014] Step S1: Determine the machining contour type and style. If it is a straight line that meets the machining requirements and satisfies the requirement of a single tool entry, then directly generate the second trajectory data. Otherwise, generate the first trajectory data by adding auxiliary machining lines.

[0015] Step S2: Determine the machining contour type and style. If it is a curve that meets the curvature condition and is a concave curve, then if it meets the single-entry requirement of the machining, the fourth trajectory data is directly generated. If it does not meet the single-entry requirement, the third trajectory data is generated by adding auxiliary machining lines.

[0016] Step S3: Determine the machining contour type and style. If it is a curve that meets the curvature condition and is a convex curve, then if it meets the requirement of one-time entry, the fifth trajectory data will be generated directly. If it does not meet the requirement of one-time entry, the sixth trajectory data will be generated by adding auxiliary machining lines.

[0017] In step four, a complete processing path is finally synthesized based on the first, second, third, fourth, fifth, and sixth trajectory data from step three.

[0018] After obtaining the processing path, further obtain discontinuous multi-end processing routes. To achieve continuous processing trajectory, the maximum circle regression method is adopted. Specifically, first, construct a maximum circle path that does not interfere with cutting around the workpiece. Then, connect all processed paths to the maximum circle. Move to the position closest to the next processing start point on the large circle, then move to the processing start point again, perform processing again, and then return to the position of the nearest circle after processing to form a continuous processing trajectory. After obtaining all processing trajectories, discretize them into data points with equal step size to form trajectory point coordinate data.

[0019] The trajectory generation method is used in articulated sawing machines, which include an articulated robotic arm with an attached band saw and a workpiece table (9) for fixing the workpiece.

[0020] The articulated robotic arm includes articulated robotic arm one (3) and articulated robotic arm two (5); the articulated robotic arm is driven by a first servo motor (1) and a second servo motor (4).

[0021] The first servo motor (1) controls the joint robotic arm one (3) to rotate around the Z-axis, the second servo motor (4) controls the joint robotic arm two (5) to rotate around the Z-axis, and the third servo motor (10) controls the workpiece stage (9) to rotate around the Z-axis.

[0022] The workpiece is a faucet casting (8). The servo motor controls the three machining axes to allow the faucet casting to be processed by the sawing machine (7) at any angle in the plane, thereby realizing curve processing.

[0023] During the workpiece processing, the workpiece table uses a hydraulic clamp (6) to press down and fix the faucet casting (8) workpiece to prevent it from sliding and relative displacement during processing.

[0024] After the faucet casting (8) is processed, it is moved into the collection box (11).

[0025] This invention provides a method for generating the trajectory of an articulated robotic arm for faucet gates. This method employs a multi-joint robotic arm structure, achieving greater spatial freedom and allowing the cutting tool to process the workpiece to the maximum extent possible, thus solving the problem of machining complex external contours with intersecting curves and straight lines. This invention uses an articulated robotic arm combined with a band saw structure, which can be used to meet the needs of various faucet models. Its flexible joints provide a larger processing space for the workpiece, enabling more complex processing paths, and providing hardware structural and functional support for subsequent trajectory generation methods.

[0026] To address the problems and shortcomings of existing technologies, this invention proposes a method for generating the trajectory of a robotic arm for a faucet gate. The system developed in this invention is written in C#. It obtains the outer contour data by reading the workpiece's DXF file, categorizes and organizes the data, selects the machining contour, establishes constraints based on the previous contour data, and determines the machining contour type and style, whether it meets machining requirements, the machining direction, whether repeated tool entry is needed, and whether auxiliary machining is required. After meeting the constraints, a machining path that meets the requirements is generated for this contour. Then, machining contours are selected sequentially to ultimately generate a continuous machining path. In this invention, by reading the part's DXF file, the outer contour image of the part is obtained. Using the contour image data as a benchmark, the contour data is categorized, and then a classification and filtering algorithm is used to generate a continuous, machinable trajectory. The method described in this invention, through a trajectory generation algorithm, solves the problem of quickly generating machining trajectories even for different workpieces, achieving machining automation and improving machining efficiency. Compared with existing products, this product replaces manual sawing in the market, achieving a higher degree of intelligence and industrialization. Furthermore, this product uses a three-joint robotic arm, which has a high degree of freedom and can perform flexible processing, including some curved surface sawing. It also has a complete control system that is simple to operate and easy to learn. In terms of efficiency and precision, it is more competitive than existing products. The development cost is low, and the cutting tool is an inexpensive saw blade. Considering all the technologies and costs, this product is more competitive. Attached Figure Description

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0028] Appendix Figure 1 This is a schematic diagram of the hardware structure of the present invention;

[0029] Appendix Figure 2 This is a flowchart illustrating the method described in this invention;

[0030] Appendix Figure 3 This is a schematic diagram of the specific trajectory generation process of the method described in this invention;

[0031] Appendix Figure 4 This is a DXF outline diagram of the faucet casting.

[0032] In the diagram: 1-First servo motor; 2-Base; 3-Articulated robotic arm one; 4-Second servo motor; 5-Articulated robotic arm two; 6-Hydraulic clamp; 7-Sawing machine; 8-Faucet casting; 9-Workpiece table; 10-Third servo motor; 11-Collection box. Detailed Implementation

[0033] As shown in the figure, the method for generating the trajectory of a sawing machine with an articulated robotic arm uses a multi-jointed robotic arm to expand the spatial degree of freedom of the tool in processing the workpiece. When dealing with complex outer contours where curves and straight lines meet, the method includes the following steps.

[0034] Step 1: Read the DXF file of the part to obtain the outer contour drawing of the part.

[0035] Step 2: Based on the contour graphic data, classify the contour data and select the contours to be processed;

[0036] Step 3: Classify and filter the processing contours using an algorithm. Specifically, based on the contour data, establish constraints and generate a continuous, processable trajectory for the contour using multiple constraints.

[0037] Step 4: Process along the machining contour sequentially, and generate a continuous machining path based on the data points discretized from the trajectory route.

[0038] The constraints in step three include: determining the machining contour type and style, determining whether the machining requirements are met, determining the machining direction, determining whether the machining requires repeated tool entry, and determining whether auxiliary machining is required.

[0039] In step three, the read contour data are arranged and categorized in order. By selecting the processing contour, the previous processing contour data and the next contour data are obtained. Furthermore, the upper and lower boundary data connected to the processing contour are obtained, and it is determined whether they are straight lines or curves.

[0040] Step three includes the following steps;

[0041] Step S1: Determine the machining contour type and style. If it is a straight line that meets the machining requirements and satisfies the requirement of a single tool entry, then directly generate the second trajectory data. Otherwise, generate the first trajectory data by adding auxiliary machining lines.

[0042] Step S2: Determine the machining contour type and style. If it is a curve that meets the curvature condition and is a concave curve, then if it meets the single-entry requirement of the machining, the fourth trajectory data is directly generated. If it does not meet the single-entry requirement, the third trajectory data is generated by adding auxiliary machining lines.

[0043] Step S3: Determine the machining contour type and style. If it is a curve that meets the curvature condition and is a convex curve, then if it meets the requirement of one-time entry, the fifth trajectory data will be generated directly. If it does not meet the requirement of one-time entry, the sixth trajectory data will be generated by adding auxiliary machining lines.

[0044] In step four, a complete processing path is finally synthesized based on the first, second, third, fourth, fifth, and sixth trajectory data from step three.

[0045] After obtaining the processing path, further obtain discontinuous multi-end processing routes. To achieve continuous processing trajectory, the maximum circle regression method is adopted. Specifically, first, construct a maximum circle path that does not interfere with cutting around the workpiece. Then, connect all processed paths to the maximum circle. Move to the position closest to the next processing start point on the large circle, then move to the processing start point again, perform processing again, and then return to the position of the nearest circle after processing to form a continuous processing trajectory. After obtaining all processing trajectories, discretize them into data points with equal step size to form trajectory point coordinate data.

[0046] The trajectory generation method is used in an articulated sawing machine, which includes an articulated robotic arm with an attached band saw, and a workpiece table 9 for fixing the workpiece.

[0047] The articulated robotic arm includes articulated robotic arm 1 3 and articulated robotic arm 2 5; the articulated robotic arm is driven by a first servo motor 1 and a second servo motor 4.

[0048] The first servo motor 1 controls the joint robotic arm 1 3 to rotate around the Z-axis, the second servo motor 4 controls the joint robotic arm 2 5 to rotate around the Z-axis, and the third servo motor 10 controls the workpiece stage 9 to rotate around the Z-axis.

[0049] The workpiece is a faucet casting 8. The servo motor controls the three machining axes to allow the faucet casting to be processed by the sawing machine 7 at any angle in the plane, thereby achieving curve processing.

[0050] During the workpiece processing, the workpiece table uses a hydraulic clamp 6 to press down and fix the faucet casting 8 workpiece to prevent it from sliding and relative displacement during processing.

[0051] After the faucet casting 8 is processed, it is moved into the collection box 11.

[0052] In this example, a corresponding host computer program was developed for the product. It reads DXF files based on different workpieces, selects the contour to be processed in the program, and then generates the corresponding trajectory and joint variables. A motion control card controls three servo motors, and the host computer monitors the speed and acceleration of each joint variable in real time, continuously correcting it during processing. The workpiece, a faucet casting, is placed according to the coordinates in the DXF file, hydraulic clamping is activated, and the robotic arm is started via the host computer, thus beginning the predetermined processing path.

[0053] In this example, DXF (Drawing Exchange Files) is a data format in AutoCAD that supports open data exchange. It contains both graphic and non-graphical information, organized into blocks and recorded using a specific format. Entities in the entity segment include: points, lines, circles, arcs, polylines, lines, text, and shapes. This example reads primarily curves and lines from the DXF file, as shown in the drawing; it includes data type, start coordinates, end coordinates, layer, and color code, as shown in the table below.

[0054]

[0055]

[0056] The read contour data is arranged and categorized sequentially. By selecting the machining contour, the previous and next machining contour data can be obtained, along with the upper and lower boundary data connected to the machining contour, and it can be determined whether it is a straight line or a curve. Figure 4 As shown, when we select machining contour a2, we obtain the upper and lower machining contours a1 and a3. Let the vector of the end point of machining contour 1 be K1, the vector of the start point of machining contour a2 be K2, the vector of the end point of machining contour 2 be K3, and the vector of the start point of machining contour 3 be K4. By judging the relationship between the sizes of K1 and K2 and the sizes of K3 and K4, we determine whether the tool can enter, the entry point, and whether the tool can exit after entry. Logical constraints are constructed between K1, K2, K3, and K4, and the subsequent machining path is constructed based on the logical constraints.

[0057]

[0058] After obtaining the machining path, we can obtain discontinuous multi-ended machining paths. To achieve trajectory continuity, maximum circle regression is used to construct a maximum circle path that does not interfere with cutting around the workpiece. All completed machining paths are connected to the maximum circle. The tool moves to the position closest to the next machining start point on the large circle, then moves back to the machining start point, performs machining again, and then returns to the position of the nearest circle after machining, forming a continuous machining trajectory. After obtaining all machining trajectories, they are discretized into data points with equal step sizes to form trajectory point coordinate data. The data points represent the tool's coordinates relative to the workpiece (X, Y, i, j) and the step size. X is the tool's x-coordinate, Y is the tool's y-coordinate, and i and j are the tool's direction vectors. The example table shows the three parts of the data.

Claims

1. A method for generating the trajectory of a sawing machine using an articulated robotic arm, characterized in that: The method employs a multi-joint robotic arm to expand the spatial degrees of freedom for the cutting tool in machining the workpiece. When dealing with complex external contours where curves and straight lines intersect, the method includes the following steps: Step 1: Read the DXF file of the part to obtain the outer contour drawing of the part. Step 2: Based on the contour graphic data, classify the contour data and select the contours to be processed; Step 3: Classify and filter the processing contours using an algorithm. Specifically, based on the contour data, establish constraints and generate a continuous, processable trajectory for the contour using multiple constraints. Step 4: Process along the machining contour sequentially, and generate a continuous machining path based on the data points discretized from the trajectory route. In step three, the read contour data are arranged and categorized in order. By selecting the processing contour, the previous processing contour data and the next contour data are obtained. Furthermore, the upper and lower boundary data connected to the processing contour are obtained, and it is determined whether they are straight lines or curves. Step three includes the following steps; Step S1: Determine the machining contour type and style. If it is a straight line that meets the machining requirements and satisfies the requirement of a single tool entry, then directly generate the second trajectory data. Otherwise, generate the first trajectory data by adding auxiliary machining lines. Step S2: Determine the machining contour type and style. If it is a curve that meets the curvature condition and is a concave curve, then if it meets the single-entry requirement of the machining, the fourth trajectory data is directly generated. If it does not meet the single-entry requirement, the third trajectory data is generated by adding auxiliary machining lines. Step S3: Determine the machining contour type and style. If it is a curve that meets the curvature condition and is a convex curve, then if it meets the requirement of one-time entry, the fifth trajectory data will be generated directly. If it does not meet the requirement of one-time entry, the sixth trajectory data will be generated by adding auxiliary machining lines.

2. The method for generating the trajectory of a sawing machine with an articulated robotic arm according to claim 1, characterized in that: The constraints in step three include: determining the machining contour type and style, determining whether the machining requirements are met, determining the machining direction, determining whether the machining requires repeated tool entry, and determining whether auxiliary machining is required.

3. The method for generating the trajectory of a sawing machine with an articulated robotic arm according to claim 1, characterized in that: In step four, a complete processing path is finally synthesized based on the first, second, third, fourth, fifth, and sixth trajectory data from step three. After obtaining the processing path, further obtain discontinuous multi-segment processing routes. To achieve continuous processing trajectory, the maximum circle regression method is adopted. Specifically, first, construct a maximum circle path that does not interfere with cutting around the workpiece. Then, connect all processed paths to the maximum circle. Move to the position closest to the next processing start point on the large circle, then move to the processing start point again, perform processing again, and then return to the position of the nearest circle after processing to form a continuous processing trajectory. After obtaining all processing trajectories, discretize them into data points with equal step sizes to form trajectory point coordinate data.

4. The method for generating the trajectory of a jointed robotic arm sawing machine according to claim 3, characterized in that: The trajectory generation method is used in articulated sawing machines, which include an articulated robotic arm with an attached band saw and a workpiece table (9) for fixing the workpiece.

5. The method for generating the trajectory of a sawing machine with an articulated robotic arm according to claim 4, characterized in that: The articulated robotic arm includes articulated robotic arm one (3) and articulated robotic arm two (5); the articulated robotic arm is driven by a first servo motor (1) and a second servo motor (4).

6. The method for generating the trajectory of a sawing machine with an articulated robotic arm according to claim 5, characterized in that: The first servo motor (1) controls the joint robotic arm one (3) to rotate around the Z-axis, the second servo motor (4) controls the joint robotic arm two (5) to rotate around the Z-axis, and the third servo motor (10) controls the workpiece stage (9) to rotate around the Z-axis.

7. The method for generating the trajectory of a sawing machine with an articulated robotic arm according to claim 6, characterized in that: The workpiece is a faucet casting (8). The servo motor controls the three machining axes to allow the faucet casting to be processed by the sawing machine (7) at any angle in the plane, thereby realizing curve processing.

8. The method for generating the trajectory of a sawing machine with an articulated robotic arm according to claim 6, characterized in that: During the workpiece processing, the workpiece table uses a hydraulic clamp (6) to press down and fix the faucet casting (8) workpiece to prevent it from sliding and relative displacement during processing.

9. The method for generating the trajectory of a sawing machine with an articulated robotic arm according to claim 6, characterized in that: After the faucet casting (8) is processed, it is moved into the collection box (11).

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