Plate workpiece flexible bending method based on laser scanning system

Abstract

The invention relates to a plate workpiece flexible bending method based on a laser scanning system, and the method comprises the following steps: S1, recognizing the size information of a plate by using the laser scanning system, and calculating the grabbing coordinate point of the center of the plate workpiece relative to a robot coordinate system; s2, calibration conversion is conducted on the relative position of the grabbing coordinate point position in the step S1 and the robot; s3, a control command is sent to the robot according to the size information of the plate workpiece and the calibration conversion result; s4, the robot grabs the plate workpieces and calculates the dimensional deviation between the current plate workpiece and the template plate workpiece; s5, point location data offset is executed in the robot tool coordinate system, and the relative position of the robot and the bending machine can be automatically adjusted when the plate workpieces of different sizes are grabbed; and S6, the position of the bending line is controlled, and automatic flexible bending of the plate workpieces of different sizes is achieved. The automatic bending machine is high in automation degree, high in flexibility, high in efficiency, high in precision and suitable for bending production requirements of large-batch plates of various specifications and sizes.

Description

Technical Field

[0001] The invention belongs to the field of automation technology, and in particular relates to a flexible bending method for a sheet metal workpiece based on a laser scanning system.

[0002] Background Technology

[0003] Transformer box wall reinforcement iron is one of the core components of large transformer oil tanks. Since large transformers are highly customized products, each transformer oil tank needs to match more than ten box wall reinforcement irons of different lengths and sizes. The length of the box wall reinforcement iron sheet is generally between 1500 and 5000 mm, the width is between 500 and 900 mm, and the weight is between 50 and 350 kg. In most cases, the lengths and dimensions of each model of box wall reinforcement iron are different and the weight is very large, so it is impossible to design special tooling and fixtures for transportation. Therefore, during the transportation of the sheet materials, manual operation of the crane is used to lift them with strong magnets. Manual operation of the crane and manual bending are also required during the bending operation. How to efficiently solve the bending problem of box wall reinforcement iron sheets of different lengths and widths is particularly important. The bending process of the box wall reinforcement iron is a key process in the manufacture of large transformer oil tanks. It is difficult to accurately control the lifting position of the sheet metal by manual crane lifting, so it is impossible to accurately control the bending line and bending angle. The manufacturing efficiency and quality of the bending process have a great impact on the manufacturing of transformer oil tanks.

[0004] With the rapid development of domestic industrial manufacturing industry, the competition in large transformer manufacturing industry is becoming increasingly fierce. How to improve production efficiency while improving product quality and implement safety production responsibility requirements to improve competitiveness has become a difficult problem facing enterprises.

[0005] The traditional box wall reinforcement iron bending process uses manual measurement of sheet metal size and manual calculation, and then uses a crane to control a strong magnet to lift the sheet metal to the appropriate position. The bending operation relies on workers to simultaneously operate a small crane and a bending machine. The bending line is controlled by the worker manipulating the relative position of the crane and the bending machine, and the bending angle is controlled by the worker's naked eye and experience.

[0006] With the advancement of technology, the industry currently adopts the method of manually lifting the sheet metal to the centering table for positioning against the edge and then using robots to carry it for bending operations. Since robots have the advantages of high repeatability and large load, using robots to carry and bend can better control the bending line and angle.

[0007] However, due to the different lengths and widths of the sheets used to process the transformer oil tank, the bending of the sheets depends on the coordinated operation of the workers' hands, eyes and feet (one-handed operation of the crane to use a strong magnet to adsorb the sheet and then hoist it to the mold clamping position of the bending machine, use tape measures, calipers, angle rulers, etc. for surveying and mapping, manual calculations after mapping, manual observation of the bending status of the sheet while stepping on the pedal of the bending machine, and adjustment of the position of the sheet and the bending machine based on experience to operate the crane lifting and walking position to control the bending line and bending angle of the sheet). Workers use strong magnets to lift sheets weighing more than 100 kilograms at close range, which is labor-intensive, unsafe and poses a risk of personal injury. Workers rely on visual observation to judge the processing status of the sheet after bending, which leads to poor consistency of the processed products. During the processing, workers with certain experience are required to use tape measures, calipers, angle rulers and other measurements and calculations many times before operating the equipment to perform bending processing. The processing efficiency and precision are low, and the labor cost is high. In addition, the centering table is used for positioning and then the robot is used for handling and bending. The mechanical positioning of the centering table can only achieve one-to-one positioning, so different centering tables need to be designed for different types of sheets. Such planning will lead to a significant increase in the cost of site, robot arm span, etc.

[0008] In summary, there is an urgent need to provide a flexible bending method for sheet metal workpieces based on a laser scanning system, which has the advantages of high automation, high flexibility, high efficiency and high precision and can be suitable for the bending production needs of large quantities of sheet metals of various specifications and sizes. Summary of the invention

[0009] The purpose of the present invention is to provide a flexible bending method for sheet metal workpieces based on a laser scanning system, which has the advantages of high automation, high flexibility, high efficiency and high precision and can be applied to the bending production needs of large quantities of sheet metals with various specifications and sizes.

[0010] The above object is achieved through the following technical solution: A flexible bending method of sheet metal workpiece based on a laser scanning system, using a robot for handling and bending, comprising the following steps:

[0011] S1, using the laser scanning system to identify the size information of the sheet material and calculate the grabbing coordinate point of the center of the sheet material workpiece relative to the robot coordinate system;

[0012] S2, calibrating and converting the grabbing coordinate points in step S1 and the relative position of the robot;

[0013] S3, sending a control command to the robot according to the size information of the sheet workpiece and the calibration conversion result;

[0014] S4, the robot grabs the sheet workpiece and calculates the size deviation between the current sheet workpiece and the template sheet workpiece;

[0015] S5, performs point data offset in the robot tool coordinate system to automatically adjust the relative position of the robot and the bending machine when grabbing sheet metal workpieces of different sizes;

[0016] S6, controls the position of the bending line to achieve automatic flexible bending of sheet metal workpieces of different sizes;

[0017] In the specific application process, the length and width dimension information of the sheet material workpiece to be bent is identified by laser scanning, and then the grabbing coordinate point of the center of the sheet material workpiece relative to the robot coordinate system is calculated by the algorithm, and then the relative position of the grabbing point position and the robot is calibrated and converted, and the relevant data packet is sent to the robot in the form of network communication, and then the robot automatically controls the robot gripper to grab the sheet material after receiving the length and width dimensions and grabbing coordinates. The robot calculates the size deviation between the current sheet material workpiece and the template sheet material workpiece through the center coordinates and length and width dimension information of the sheet material workpiece, and performs point data offset in the robot tool coordinate system, so that the relative position of the robot and the bending machine can be automatically adjusted when grabbing sheets of different length and width dimensions, and then the position of the bending line is controlled, so as to realize the automatic flexible bending of different types of workpieces. This method has good processing consistency, fast speed, and the robot grabbing position adjustment is quick and simple. The present invention can use the laser scanning system to identify sheets of different lengths and widths to locate, grab and bend, solve the pain points and difficulties of sheets of different lengths and widths, and is suitable for the needs of large-scale bending production of multiple sizes.

[0018] A further technical solution is that the laser scanning system includes a line laser scanning module, and the step S1 also includes a calibration step:

[0019] S01, calibrate the position of the robot's gripper in the robot coordinate system;

[0020] S02, calibrating the position conversion relationship between the robot coordinate system and the coordinate system of the line laser scanning module;

[0021] S03, calibrating the rotation angle conversion relationship between the robot coordinate system and the coordinate system of the line laser scanning module;

[0022] S04, calculating the size information of the template sheet workpiece and the center coordinates of the gripper relative to the robot coordinate system according to the imaging data of the template sheet workpiece in the laser scanning system;

[0023] S05, the robot debugs the bending line of the template workpiece through the data information provided by the laser scanning system, and establishes a set of internal parameters as the data offset information in step S5.

[0024] A further technical solution is that the specific steps of step S01 are as follows:

[0025] S0101, Install the first teaching tool onto the gripper of the robot. The size of the first teaching tool matches the corresponding fixture of the gripper, so that the end point of the first teaching tool is in the same position as the grasping point of the gripper.

[0026] S0102, Fix and install the second teaching tool within the working range of the robot. Control the movement of the robot's gripper so that the tips of the first teaching tool and the second teaching tool can be aligned when the robot's gripper is in at least four significantly different postures.

[0027] S0103, The robot teach pendant records the coordinate data of four different postures of the robot's gripper in step S0102, and calculates the coordinates of the initial position of the first teaching tool on the robot's gripper. These coordinates are the coordinates of the initial position of the robot's gripper in the robot coordinate system.

[0028] A further technical solution is that the specific steps of step S02 are as follows:

[0029] S0201, The robot gripper grasps the calibrated template sheet metal workpiece, controls the robot gripper to move the template sheet metal workpiece to a specific height within the range of the loading table, controls the line laser scanning module to scan and image, and observes whether the template sheet metal workpiece is within the imaging range.

[0030] S0202, Calibrate the template sheet metal workpiece, and calculate the position conversion relationship between the robot coordinate system and the line laser scanning module coordinate system.

[0031] A further technical solution is that the specific steps of step S0202 are as follows: Control the template workpiece to move 9 positions along a "field" shape. Each time the robot gripper moves, control the line laser scanning module to scan and image once, and record the coordinate values of the 9 robot coordinate systems and the line laser scanning imaging coordinate values respectively. Use the coordinates in the robot coordinate system and the line laser scanning imaging coordinates collected, and calculate a 3*3 transformation matrix by the least squares method. Establish the conversion relationship between the central coordinates of the line laser scanning imaging and the central coordinates of the robot gripper through the transformation matrix.

[0032] A further technical solution is that the specific steps of step S03 are as follows:

[0033] S0301, the robot gripper grabs the calibrated template sheet workpiece, controls the robot gripper to move the calibrated workpiece to a specific height within the range of the loading platform, and then the line laser scanning module moves synchronously in opposite directions to scan the contour information of the template workpiece on the current loading platform, and compares the actual measured size information of the template sheet workpiece with the imaging information scanned by the line laser scanning module to calculate the conversion relationship between the scanned image size and the actual size of the template sheet workpiece;

[0034] S0302, obtaining the coordinate data of the two vertices of the imaging information, calculating the coordinate data of the center position, and further obtaining the coordinate point of the gripping object of the robot gripper according to the conversion relationship between the scanned image size and the actual size;

[0035] S0303, operate the robot to move to the grabbing coordinate point, adjust the outer edge of the robot gripper to be level with the outer edge of the template sheet workpiece, then control the robot gripper to grab the template sheet workpiece, then the loading station electrically detaches the template sheet workpiece, operate the robot to rotate a preset angle along the horizontal plane to ensure that the template sheet workpiece is fully imaged in the laser scanning system, record the rotation angle of the point coordinate data in the robot coordinate system, and control the line laser scanning module to scan the template workpiece and image it;

[0036] S0304, operate the robot again to rotate a predetermined angle in the opposite direction along the horizontal plane, record the rotation angle of the point coordinate data in the robot coordinate system, control the line laser scanning module to scan the template workpiece and form an image, and then derive the rotation angle conversion relationship between the robot coordinate system and the line laser scanning module coordinate system based on the two image data changes and the position conversion relationship between the robot coordinate system and the line laser scanning module coordinate system.

[0037] A further technical solution is that the specific steps of step S05 are as follows:

[0038] S0501, the robot gripper moves to the position according to the grasping point coordinates given by the line laser scanning system, grabs the template sheet workpiece, and the loading platform is separated from the template sheet workpiece;

[0039] S0502, the robot gripper moves the template sheet workpiece to the lifting range of the bending machine mold, teaches the relative position of the template sheet workpiece and the bending machine, and the template sheet workpiece is laid flat on the lower mold of the bending machine. The distance between the edge of the template sheet workpiece and the center line of the lower mold of the bending machine is the bending line data. At the same time, a set of internal parameters is established in the robot register as data offset information, and the data offset information includes the length, width, and bending line data information of the template sheet workpiece;

[0040] In step S5, after completing the calibration and teaching production work of the first template sheet workpiece, when subsequently processing the sheet workpiece with different length and width dimensions, the robot compares the dimension information given by the laser scanning system with the dimension information of the template sheet workpiece, calculates the difference between the two sets of dimension information, and uses the data offset information in the robot's internal register to make an offset based on the calculation result, thereby realizing automatic flexible bending of the robot system.

[0041] A further technical solution is that the line laser scanning module is arranged in the middle position of the loading platform, and the two line laser scanning modules are arranged along the diagonal position. The line laser scanning modules can move synchronously in opposite directions in the horizontal direction. The loading platform and the bending machine are arranged within the working range of the robot, and the loading platform has the function of moving forward and backward in the horizontal direction and lifting up and down in the vertical direction.

[0042] During specific application, the robot, its gripper and the loading platform are equipped with two sets of electromagnet devices, which are respectively used for the loading platform to lift the sheet workpiece to a specific height, so that the line laser scanning system scans the sheet workpiece and the robot gripper has enough space to grasp it.

[0043] Compared with the prior art, the technical solution of the present invention only needs to calibrate and debug one template workpiece, and can utilize the calculation function of the line laser scanning system. There is no need to perform feature extraction and measurement on sheet workpieces of various sizes. The line laser scanning system integrates the size information measurement and recognition and parameter calibration functions. The robot can directly quote the coordinate values ​​and size information calculated by the line laser scanning system to realize the grasping and bending of sheet workpieces of various sizes. Only one calibration and debugging is required, which shortens the production cycle, improves efficiency, reduces labor intensity, greatly reduces costs, and improves the intelligence and flexibility of the robot bending system. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0045] Figure 1 A schematic flow chart of a sheet metal workpiece flexible bending method based on a laser scanning system according to an embodiment of the present invention;

[0046] Figure 2 A schematic diagram of a calibration process in a sheet metal workpiece flexible bending method based on a laser scanning system according to an embodiment of the present invention;

[0047] Figure 3 It is a schematic diagram of the layout of a robot flexible bending system involved in one embodiment of the present invention.

[0048] In the figure:

[0049] 1 loading table 2 robot 3 bending machine DETAILED DESCRIPTION

[0050] The present invention is described in detail below in conjunction with the accompanying drawings. The description in this part is only exemplary and explanatory and should not have any limiting effect on the scope of protection of the present invention. In addition, those skilled in the art can make corresponding combinations of the features in the embodiments and in different embodiments in this document based on the description of this document.

[0051] The embodiments of the present invention are as follows, referring to Figure 1 and Figure 2 , a flexible bending method of sheet metal workpiece based on laser scanning system, a robot flexible bending system based on line laser scanning system, the robot handling bending system includes a loading platform 1, a bending machine 3 and a robot 2, the loading platform 1 includes a line laser scanning module, a loading platform lifting mechanism, a loading platform electromagnet, and a loading platform sliding mechanism; the bending machine 3 includes a bending machine body and a bending machine lower mold; the robot 1 includes a robot body and a robot gripper; the loading platform 1 and the bending machine 3 are located within the operating range of the robot 2. The loading platform 1 has the functions of horizontal forward and backward movement and vertical upward and downward lifting, the line laser scanning module is arranged in the middle of the loading platform 1, and there are two units arranged along the diagonal position, which have the function of horizontal opposite synchronous movement, the robot 2 and its gripper and the loading platform are equipped with two sets of electromagnet devices, which are respectively used for the loading platform 2 to lift the sheet metal workpiece to a specific height, so that the line laser scanning system scans the sheet metal workpiece and the robot 2 gripper has enough space to grasp.

[0052] Specifically, the flexible bending method of a sheet metal workpiece based on a laser scanning system includes the following steps:

[0053] S1, using the laser scanning system to identify the size information of the sheet material and calculate the grabbing coordinate point of the center of the sheet material workpiece relative to the robot coordinate system;

[0054] S2, calibrating and converting the grabbing coordinate points in step S1 and the relative position of the robot;

[0055] S3, sending a control command to the robot according to the size information of the sheet workpiece and the calibration conversion result;

[0056] S4, the robot grabs the sheet workpiece and calculates the size deviation between the current sheet workpiece and the template sheet workpiece;

[0057] S5, performs point data offset in the robot tool coordinate system to automatically adjust the relative position of the robot and the bending machine when grabbing sheet metal workpieces of different sizes;

[0058] S6, controls the position of the bending line to achieve automatic flexible bending of sheet metal workpieces of different sizes;

[0059] In the specific application process, the length and width dimension information of the sheet material workpiece to be bent is identified by laser scanning, and then the grabbing coordinate point of the center of the sheet material workpiece relative to the robot coordinate system is calculated by the algorithm, and then the relative position of the grabbing point position and the robot is calibrated and converted, and the relevant data packet is sent to the robot in the form of network communication, and then the robot automatically controls the robot gripper to grab the sheet material after receiving the length and width dimensions and grabbing coordinates. The robot calculates the size deviation between the current sheet material workpiece and the template sheet material workpiece through the center coordinates and length and width dimension information of the sheet material workpiece, and performs point data offset in the robot tool coordinate system, so that the relative position of the robot and the bending machine can be automatically adjusted when grabbing sheets of different length and width dimensions, and then the position of the bending line is controlled, so as to realize the automatic flexible bending of different types of workpieces. This method has good processing consistency, fast speed, and the robot grabbing position adjustment is quick and simple. The present invention can use the laser scanning system to identify sheets of different lengths and widths to locate, grab and bend, solve the pain points and difficulties of sheets of different lengths and widths, and is suitable for the needs of large-scale bending production of multiple sizes.

[0060] Based on the above embodiment, in another embodiment of the present invention, Figure 2 , the step S1 also includes a calibration step:

[0061] S01, calibrate the position of the robot's gripper in the robot coordinate system;

[0062] S0101, installing a first teaching piece (a steel needle may be used) onto the gripper of the robot, wherein the size of the first teaching piece matches the corresponding fixture of the gripper, so that the end point of the first teaching piece is consistent with the position of the gripping point of the gripper;

[0063] S0102, a second teaching piece (a steel needle may be used) is fixedly installed within the operating range of the robot, and the gripper of the robot is controlled to move so that the gripper of the robot can align the tips of the first teaching piece and the second teaching piece when the gripper is in at least four different postures with large differences;

[0064] S0103, the robot teaching pendant records the coordinate data of the four different postures of the robot's gripper in step S0102, and calculates the coordinates of the initial position of the first teaching piece on the robot's gripper, which are the coordinates of the initial position of the robot's gripper in the robot coordinate system.

[0065] S02, calibrating the position conversion relationship between the robot coordinate system and the coordinate system of the line laser scanning module;

[0066] S0201. The robot gripper grasps the template sheet metal workpiece for calibration, controls the robot gripper to move the template sheet metal workpiece to a specific height within the range of the loading table, controls the line laser scanning module to scan and image, and observes whether the template sheet metal workpiece is within the imaging range;

[0067] S0202. Calibrate the template sheet metal workpiece, and calculate the position conversion relationship between the robot coordinate system and the line laser scanning module coordinate system. The specific steps are as follows: Control the template workpiece to move 9 positions along the "field" shape. Each time the robot gripper moves, control the line laser scanning module to scan and image once, and record the coordinate values (x i , y i , r i ) of the 9 robot coordinate systems and the line laser scanning imaging coordinate values respectively, where (x i , y i ) is the center coordinate of the robot gripper, and r i represents the rotation angle (only move x and y during the movement process, not r); Use the coordinates in the robot coordinate system and the line laser scanning imaging coordinates collected, and calculate a 3*3 transformation matrix by the least squares method, and establish the conversion relationship between the center coordinates of the line laser scanning imaging and the center coordinates of the robot gripper through the transformation matrix.

[0068] S03. Calibrate the rotation angle conversion relationship between the robot coordinate system and the coordinate system of the line laser scanning module;

[0069] S0301. The robot gripper grasps the template sheet metal workpiece for calibration, controls the robot gripper to move the calibrated workpiece to a specific height within the range of the loading table, and then the line laser scanning module makes a synchronous opposite movement to scan the contour information of the template workpiece on the current loading table. Compare the actual measurement size information of the template sheet metal workpiece with the imaging information scanned by the line laser scanning module to calculate the conversion relationship between the scanned image size and the actual size of the template sheet metal workpiece;

[0070] S0302. Take the coordinate data of two vertex positions of the imaging information, which are (xL, yL) and (xR, yR) respectively, calculate the center position coordinate data ((xL - xR) / 2, (yL - yR) / 2), and further obtain the grasping coordinate points of the robot gripper according to the conversion relationship between the scanned image size and the actual size;

[0071] S0303, operate the robot to move to the grabbing coordinate point, adjust the outer edge of the robot gripper to be level with the outer edge of the template sheet workpiece, then control the robot gripper to grab the template sheet workpiece, then the loading station electrically detaches the template sheet workpiece, operate the robot to rotate a predetermined angle (5 to 10 degrees) along the horizontal plane, ensure that the template sheet workpiece is completely imaged in the laser scanning system, record the rotation angle r1 of the point coordinate data (x1, y1, r1) in the robot coordinate system, and control the line laser scanning module to scan the template workpiece and image it;

[0072] S0304, operate the robot again to rotate a predetermined angle (5 to 10 degrees) in the opposite direction along the horizontal plane, record the rotation angle r2 of the point coordinate data (x2, y2, r2) in the robot coordinate system, control the line laser scanning module to scan the template workpiece and form an image, and then derive the rotation angle conversion relationship between the robot coordinate system and the line laser scanning module coordinate system based on the two image data changes and the position conversion relationship between the robot coordinate system and the line laser scanning module coordinate system.

[0073] S04, calculate the size information of the template sheet workpiece and the center coordinates of the gripper relative to the robot coordinate system based on the imaging data of the template sheet workpiece in the laser scanning system; based on the above two conversion relationships, when the new sheet workpiece is scanned by linear laser, the robot gripper coordinate data and rotation angle can be calculated, that is (xG, yG, rG).

[0074] S05, the robot debugs the bending line of the template workpiece through the data information provided by the laser scanning system, and establishes a set of internal parameters as the data offset information in step S5.

[0075] S0501, the robot gripper moves to the position according to the grasping point coordinates given by the line laser scanning system, grabs the template sheet workpiece, and the loading platform is separated from the template sheet workpiece;

[0076] S0502, the robot gripper moves the template sheet workpiece to the lifting range of the bending machine mold, teaches the relative position of the template sheet workpiece and the bending machine, and the template sheet workpiece is laid flat on the lower mold of the bending machine. The distance between the edge of the template sheet workpiece and the center line of the lower mold of the bending machine is the bending line data, that is, the template workpiece needs to be taught the bending line position, and at the same time, a set of internal parameters is established in the robot register as data offset information, and the data offset information includes the length, width, and bending line data information of the template sheet workpiece;

[0077] In step S5, after completing the calibration and teaching production work of the first template sheet workpiece, when subsequently processing the sheet workpiece with different length and width dimensions, the robot compares the dimension information given by the laser scanning system with the dimension information of the template sheet workpiece, calculates the difference between the two sets of dimension information, and uses the data offset information in the robot's internal register to make an offset based on the calculation result, thereby realizing automatic flexible bending of the robot system.

[0078] Compared with the prior art, the technical solution of the present invention only needs to calibrate and debug one template workpiece, and can utilize the calculation function of the line laser scanning system. There is no need to perform feature extraction and measurement on sheet workpieces of various sizes. The line laser scanning system integrates the size information measurement and recognition and parameter calibration functions. The robot can directly quote the coordinate values ​​and size information calculated by the line laser scanning system to realize the grasping and bending of sheet workpieces of various sizes. Only one calibration and debugging is required, which shortens the production cycle, improves efficiency, reduces labor intensity, greatly reduces costs, and improves the intelligence and flexibility of the robot bending system.

[0079] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A flexible bending method for sheet metal workpieces based on a laser scanning system, using a robot for handling and bending, characterized in that: The steps include: S1, using the laser scanning system to identify the size information of the sheet material and calculate the grabbing coordinate point of the center of the sheet material workpiece relative to the robot coordinate system; S2, calibrating and converting the grabbing coordinate points in step S1 and the relative position of the robot; S3, sending a control command to the robot according to the size information of the sheet workpiece and the calibration conversion result; S4, the robot grabs the sheet workpiece and calculates the size deviation between the current sheet workpiece and the template sheet workpiece; S5, performs point data offset in the robot tool coordinate system to automatically adjust the relative position of the robot and the bending machine when grabbing sheet metal workpieces of different sizes; S6 controls the position of the bending line to achieve automatic flexible bending of sheet metal workpieces of different sizes.

2. The flexible bending method of sheet metal workpiece based on laser scanning system according to claim 1 is characterized in that: The laser scanning system includes a line laser scanning module, and the step S1 also includes a calibration step: S01, calibrate the position of the robot's gripper in the robot coordinate system; S02, calibrating the position conversion relationship between the robot coordinate system and the coordinate system of the line laser scanning module; S03, calibrating the rotation angle conversion relationship between the robot coordinate system and the coordinate system of the line laser scanning module; S04, calculating the size information of the template sheet workpiece and the center coordinates of the gripper relative to the robot coordinate system according to the imaging data of the template sheet workpiece in the laser scanning system; S05, the robot debugs the bending line of the template workpiece through the data information provided by the laser scanning system, and establishes a set of internal parameters as the data offset information in step S5.

3. The sheet metal workpiece flexible bending method based on the laser scanning system according to claim 2 is characterized in that: The specific steps of step S01 are as follows: S0101, installing a first teaching piece on a gripper of the robot, wherein a size of the first teaching piece matches a corresponding fixture of the gripper, so that an end point of the first teaching piece is consistent with a gripping point of the gripper; S0102, a second teaching piece is fixedly installed within the working range of the robot, and the gripper of the robot is controlled to move so that the gripper of the robot can align the tips of the first teaching piece and the second teaching piece when the gripper of the robot is in at least four different postures with large differences; S0103, the robot teaching pendant records the coordinate data of the four different postures of the robot's gripper in step S0102, and calculates the coordinates of the initial position of the first teaching piece on the robot's gripper, which are the coordinates of the initial position of the robot's gripper in the robot coordinate system.

4. The sheet metal workpiece flexible bending method based on a laser scanning system according to claim 3 is characterized in that: The specific steps of step S02 are as follows: S0201, the robot gripper grabs the calibrated template sheet workpiece, controls the robot gripper to move the template sheet workpiece to a specific height within the range of the loading platform, controls the line laser scanning module to scan and image, and observes whether the template sheet workpiece is within the imaging range; S0202, calibrate the template sheet workpiece and calculate the position conversion relationship between the robot coordinate system and the line laser scanning module coordinate system.

5. The sheet metal workpiece flexible bending method based on the laser scanning system according to claim 4 is characterized in that: The specific steps of the step S0202 are as follows: Control the template workpiece to move 9 positions along the "field" shape. Each time the robot gripper moves, control the line laser scanning module to scan and image once, and record the coordinate values of the 9 robot coordinate systems and the line laser scanning imaging coordinate values respectively. Using the coordinates in the robot coordinate system and the line laser scanning imaging coordinates collected, calculate a 3*3 transformation matrix by the least squares method, and establish the conversion relationship between the central coordinates of the line laser scanning imaging and the central coordinates of the robot gripper through the transformation matrix.

6. The sheet metal workpiece flexible bending method based on a laser scanning system according to claim 5, characterized in that: The specific steps of the step S03 are as follows: S0301, The robot gripper grabs the calibrated template sheet metal workpiece, controls the robot gripper to move the calibrated workpiece to a specific height within the range of the loading table, and then the line laser scanning module makes a synchronous opposite movement to scan the contour information of the template workpiece on the current loading table. By comparing the actual measurement size information of the template sheet metal workpiece with the imaging information scanned by the line laser scanning module, calculate the conversion relationship between the size of the scanned image and the actual size of the template sheet metal workpiece; S0302, Take the coordinate data of two vertex positions of the imaging information, calculate the coordinate data of the central position, and further obtain the grasping coordinate point of the robot gripper according to the conversion relationship between the size of the scanned image and the actual size; S0303, Operate the robot to move to the grasping coordinate point, adjust the outer edge of the robot gripper to be horizontally flush with the outer edge of the template sheet metal workpiece, then control the robot gripper to grab the template sheet metal workpiece, and then the loading table electrically disconnects the template sheet metal workpiece. Operate the robot to rotate a predetermined angle along the horizontal plane to ensure that the template sheet metal workpiece is completely imaged in the laser scanning system, record the rotation angle of the point coordinate data in the robot coordinate system, and control the line laser scanning module to scan and image the template workpiece; S0304, Operate the robot to rotate a predetermined angle in the opposite direction along the horizontal plane again, record the rotation angle of the point coordinate data in the robot coordinate system, control the line laser scanning module to scan and image the template workpiece, and then obtain the rotation angle conversion relationship between the robot coordinate system and the coordinate system of the line laser scanning module according to the change of the two image data and the position conversion relationship between the robot coordinate system and the coordinate system of the line laser scanning module.

7. The sheet metal workpiece flexible bending method based on a laser scanning system according to claim 6, characterized in that: The specific steps of the step S05 are as follows: S0501, The robot gripper runs to this position according to the grasping point coordinate given by the line laser scanning system, grabs the template sheet metal workpiece, and the loading table disconnects the template sheet metal workpiece; S0502, The robot gripper moves the template sheet metal workpiece to within the lifting range of the bending machine die, teach the relative position between the template sheet metal workpiece and the bending machine. The template sheet metal workpiece is laid flat on the lower die of the bending machine. The distance between the edge of the template sheet metal workpiece and the center line of the lower die of the bending machine is the bending line data. At the same time, establish a set of internal parameters in the robot register as data offset information. The data offset information includes the length, width, and bending line data information of the template sheet metal workpiece; In step S5, after completing the calibration and teaching production work of the first template sheet workpiece, when subsequently processing the sheet workpiece with different length and width dimensions, the robot compares the dimension information given by the laser scanning system with the dimension information of the template sheet workpiece, calculates the difference between the two sets of dimension information, and uses the data offset information in the robot's internal register to make an offset based on the calculation result, thereby realizing automatic flexible bending of the robot system.

8. The sheet metal workpiece flexible bending method based on a laser scanning system according to claim 6, characterized in that: The line laser scanning module is arranged in the middle of the loading platform, and the two line laser scanning modules are arranged along the diagonal position. The line laser scanning modules can move synchronously in opposite directions in the horizontal direction. The loading platform and the bending machine are arranged within the working range of the robot. The loading platform has the functions of moving forward and backward in the horizontal direction and lifting up and down in the vertical direction.

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