An automatic cutting system and cutting method for old car body panels of railway wagons

Abstract

An automated cutting system and method for used railway freight car body plates belongs to the field of welding automation technology. This invention addresses the problems of low cutting efficiency, high labor intensity, and poor cutting quality due to variations in human skill levels when cutting plates with uneven thickness and lacking reliable external positioning references. The invention includes a six-axis industrial robot, a torch mounting bracket, a torch, a laser rangefinder, a camera mounting bracket, a photo recognition camera, a camera mounting bracket, a pen-tube camera, and an optical axis. The torch is mounted at the end of the six-axis industrial robot arm via the torch mounting bracket. The laser rangefinder is mounted on one side of the torch, and the optical axis is located on the other side. The photo recognition camera is mounted on the optical axis via the camera mounting bracket, and the pen-tube camera is mounted on the optical axis via the camera mounting bracket, positioned outside the photo recognition camera. This invention is primarily used for cutting used railway freight car bodies.

Description

Technical Field

[0001] This invention belongs to the field of welding automation technology, and in particular relates to an automatic cutting system and method for used railway freight car body plates. Background Technology

[0002] The operating conditions of railway freight cars in my country are harsh. The steel structure of the car body not only has to withstand the friction and corrosion of cargo in a full-temperature environment, but also the impact of loading and unloading machinery. The protective layers inside and outside the car body are damaged in a short period of time. Later, under the combined effects of rainwater and other corrosive media, the car body base is corroded, the rust layer is destroyed, and eventually the car body gradually thins until it perforates and fails. The traditional method of freight car repair is to manually cut the old car body using a hand-held flame torch and then patch it. However, the positioning of the car body after entering the repair section is not accurate, and the positioning reference of the old railway freight car body plates is completely lost due to various external forces. Therefore, the positioning reference is completely lost in automated cutting operations, making it unsuitable for automated cutting. Moreover, the cutting trajectory of the car body is affected by external wear, and the thickness of the plates is uneven. Therefore, in order to ensure the straightness of the cut and control the amount of slag, it is necessary to constantly adjust the ratio of oxygen and fuel gas to regulate the length of the air line to accommodate different plate thicknesses. Summary of the Invention

[0003] The technical problem to be solved by this invention is that for cutting operations with no reliable external positioning reference and uneven plate thickness, there are problems such as low cutting efficiency, high labor intensity, or low cutting quality due to differences in human skills. In order to improve the level of automation / intelligence, improve cutting efficiency and quality, and reduce the labor intensity of workers, this application proposes an automatic cutting system and cutting method for old railway freight car body plates, which has a positive effect on further promoting the automation level of railway freight car body maintenance operations.

[0004] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0005] An automated cutting system for used railway freight car body panels includes a six-axis industrial robot, a torch mounting bracket, a torch, a laser rangefinder, a camera mounting bracket, a photo recognition camera, a camera mounting bracket, a pen-tube camera, and an optical axis. The torch is mounted on the end of the six-axis industrial robot's robotic arm via the torch mounting bracket. The laser rangefinder is mounted on one side of the torch, and the optical axis is located on the other side of the torch. The photo recognition camera is mounted on the optical axis via the camera mounting bracket, and the pen-tube camera is mounted on the optical axis via the camera mounting bracket, with the pen-tube camera positioned outside the photo recognition camera.

[0006] Furthermore, an anti-collision sensor and a mounting plate are provided between the cutting torch and the end of the six-axis industrial robot arm. The anti-collision sensor is located between the end of the six-axis industrial robot arm and the mounting plate. The laser rangefinder and the cutting torch mounting bracket are mounted horizontally side by side on the mounting plate.

[0007] Furthermore, the cutting torch mounting frame includes a U-shaped reed and two fixing blocks. The U-shaped reed is mounted on the mounting plate with screws. The upper and lower sides of the U-shaped reed are respectively provided with semi-circular notches. Each fixing block has a semi-circular notch. The semi-circular notch on each fixing block is arranged opposite to the semi-circular notch on the U-shaped reed, and the two are connected by screws. The cutting torch is vertically installed in the notch between the U-shaped reed and the two fixing blocks.

[0008] Furthermore, a glass protective cover is installed at the front end of the laser rangefinder.

[0009] Furthermore, the camera mounting bracket has the same structure as the camcorder mounting bracket. The camera mounting bracket includes a crab claw clamp, two universal joint rods, and an adjusting stud. Both ends of the universal joint rods are spherical universal joints. One end of one universal joint rod is fixed to the crab claw clamp, and the other end of one universal joint rod is connected to one end of the other universal joint rod, with their spherical universal joints communicating with each other and being secured by the adjusting stud. The other end of the other universal joint rod is connected to the photo recognition camera, and the crab claw clamp is held on the optical axis.

[0010] Furthermore, an L-shaped rod is also installed on the optical axis.

[0011] An automated cutting method for used railway freight car body panels, the specific operation steps of which are as follows:

[0012] Step 1: Pre-calibrate the position of the laser point generated by the laser rangefinder on the six-axis industrial robot and the distance between the cutting torch nozzle;

[0013] Step 2: Pre-set different cutting paths and assign a different cutting symbol to each different cutting path. The cutting symbol can be represented by numbers, letters or graphics, etc., and can be determined according to the owner's needs.

[0014] Step 3: On the cutting plate of the old railway freight car body, mark the cutting symbols by hand or by laser engraving according to the damaged area and shape of the plate.

[0015] Step 4: Use a six-axis industrial robot to move the photo recognition camera so that the photo recognition camera is aligned with the cutting symbol on the board to be cut and takes a picture. The photo taking time is 1 second.

[0016] Step 5: Use OCR technology to identify the cutting symbol, determine the cutting path it represents, and call the cutting path to send it to the six-axis industrial robot and the unloading station respectively, so as to determine the walking path and unloading path of the six-axis industrial robot.

[0017] Step 6: Coarse and fine positioning of the old railway freight car body;

[0018] Step 7: Determine the starting cutting point, key points of the path, and ending cutting point of the cutting path for the plate to be cut;

[0019] Step 8: Use a six-axis industrial robot to move the laser rangefinder to directly above the calibrated position of the board to be cut, and use the laser rangefinder to emit a laser vertically towards the board to be cut, so that a laser spot is generated on the board to be cut.

[0020] Step 9: The six-axis industrial robot moves along the cutting path, simultaneously moving the laser rangefinder, the torch, and the pen-tube camera. The pen-tube camera is used to observe the changes in wear on the surface of the plate to be cut, determine the changes in the thickness of the plate along the cutting path, and adjust the flow rate of the gas flow detection controller on the oxygen pipe and the gas pipe, thereby adjusting the length of the air duct to ensure cutting quality and achieve the goal of saving fuel.

[0021] Step 10: For the next piece of the old railway freight car body to be cut, repeat steps 3 to 9 until all the pieces of the old railway freight car body to be cut are cut off.

[0022] Step 11: Weld the new replacement sheet metal cut from the cutting station to the corresponding position on the old railway freight car body.

[0023] Furthermore, in step 1, the distance between the laser point generated by the laser ranging sensor and the cutting torch nozzle includes a horizontal distance and a vertical distance. The horizontal distance is the horizontal distance between the cutting torch nozzle and the laser point, and the vertical distance is the vertical distance between the cutting torch nozzle and the plate to be cut.

[0024] Furthermore, the specific positioning method for step 6 is as follows:

[0025] Step 6.1: Along the travel direction of the old railway freight car body, the fine positioning mechanism and the coarse positioning mechanism are installed in sequence. The coarse positioning mechanism is installed on the rail, and the fine positioning mechanism is rotatably installed on one side of the rail. A certain distance is left between the coarse positioning mechanism and the fine positioning mechanism.

[0026] Step 6.2: The old railway freight car body moves along the rail toward the coarse positioning mechanism until the wheels of the old railway freight car body touch the coarse positioning mechanism and come to a stop, thus achieving coarse positioning of the old railway freight car body.

[0027] Step 6.3: Rotate the precision positioning mechanism to the upper side of the rail, and use manpower and a winch to push the old railway freight car body in the opposite direction of the train's direction of travel, so that the old railway freight car body slowly approaches the precision positioning mechanism, thereby achieving the precision positioning of the old railway freight car body.

[0028] Furthermore, the method for determining step 7 is as follows:

[0029] Step 7.1: Determine the calibration positions of the laser rangefinder and the plate to be cut between the X, Y, and Z axes;

[0030] Step 7.2: Establish a spatial coordinate system, determine the planned path and the starting point for positioning relative to the starting cutting point of the planned path. The starting point for positioning is the calibration point of the planned path.

[0031] Step 7.3: The six-axis industrial robot drives the laser rangefinder to move along the planned path and finally stop at the positioning start point of the planned path;

[0032] Step 7.4: The six-axis industrial robot drives the laser rangefinder to move along the X-axis toward the plate to be cut until the laser rangefinder reaches the calibration position between the laser rangefinder and the plate to be cut in the X-axis direction. The distance that the laser rangefinder moves in the X-axis direction is calculated as the movement compensation amount in the X-axis direction.

[0033] Step 7.5: The six-axis industrial robot drives the laser rangefinder sensor back to the positioning start point. Then, the six-axis industrial robot drives the laser rangefinder sensor to move along the Y-axis towards the plate to be cut until the laser rangefinder sensor reaches the calibration position in the Y-axis direction between the laser rangefinder sensor and the plate to be cut. The distance that the laser rangefinder sensor moves in the Y-axis direction is calculated as the movement compensation amount in the Y-axis direction.

[0034] Step 7.6: The six-axis industrial robot drives the laser rangefinder sensor back to the positioning start point. Then, the six-axis industrial robot drives the laser rangefinder sensor to move along the Z-axis towards the plate to be cut until the laser rangefinder sensor reaches the calibration position between the laser rangefinder sensor and the plate to be cut in the Z-axis direction. The distance that the laser rangefinder sensor moves in the Z-axis direction is calculated as the Z-axis movement compensation amount.

[0035] Step 7.7: Add the movement compensation amounts in the X-axis, Y-axis and Z-axis directions to the starting cutting point, key points of the path and the ending cutting point of the planned path of the six-axis industrial robot to ensure the accuracy of the cutting path of the plate to be cut.

[0036] The beneficial effects of this invention compared to the prior art are:

[0037] 1. This application uses a six-axis industrial robot to drive the movement of a cutting torch, a laser rangefinder, a photo recognition camera, and a pen-tube camera; the cutting torch is used to cut the old railway freight car body; the laser rangefinder is used to perform ultra-precise positioning of the plate to be cut on the old railway freight car body, so as to achieve precise cutting of the plate; the photo recognition camera is used to determine the cutting path of the plate to be cut; and the pen-tube camera is used to observe the wear changes and working conditions of the surface of the plate to be cut.

[0038] 2. This application achieves the positioning of the old railway freight car body by coarse and fine positioning, and then achieves the ultra-precise positioning of the plate to be cut by the positioning method, and finally achieves the precise cutting of the plate to be cut of the old railway freight car body.

[0039] 3. This application pre-calibrates the position of the laser point generated by the laser rangefinder on the six-axis industrial robot and the distance between the cutting torch nozzle. This allows the cutting torch to pre-set the distance when tracking, avoiding the situation where the cutting torch immediately rises as soon as the laser shines on a certain high point.

[0040] 4. Due to differences in the wear degree of the plate and changes in the thickness of the plate, or when transitioning from cutting a flat plate to cutting a weld seam, the required ratio of preheating gas and preheating oxygen must be changed accordingly, or the preheating time must also be changed accordingly; that is, it needs to be changed as the thickness of the plate being cut, the cutting conditions, and the required cutting efficiency change. This application uses a pen-tube camera to observe the changes in the wear condition of the surface of the plate to be cut and the working conditions, so as to adjust the gas flow rate on the oxygen pipe and the gas pipe to ensure the cutting quality and achieve the purpose of saving fuel. Attached Figure Description

[0041] The accompanying drawings, which form part of this application, are provided to further illustrate the invention.

[0042] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0043] Figure 2 This is a partially enlarged view of the present invention.

[0044] Figure 3 This is a flow chart of the cutting process of the present invention.

[0045] Explanation of reference numerals in the attached diagram: 1-Six-axis industrial robot; 2-Anti-collision sensor; 3-Mounting plate; 4-Torch mounting bracket; 4-1-U-shaped reed; 4-2-Fixing block; 5-Torch; 6-Laser rangefinder sensor; 7-Camera mounting bracket; 7-1-Crab claw clamp; 7-2-Universal joint support rod; 7-3-Adjusting stud; 8-Photo recognition camera; 9-Camera mounting bracket; 10-Pen holder camera; 11-Optical axis; 12-L-shaped rod. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0047] See Figure 1 This application provides an automatic cutting system for used railway freight car body panels, comprising a six-axis industrial robot 1, an anti-collision sensor 2, a mounting plate 3, a torch mounting bracket 4, a torch 5, a laser rangefinder 6, a camera mounting bracket 7, a photo recognition camera 8, a camera mounting bracket 9, a pen-tube camera 10, and an optical axis 11. The anti-collision sensor 2 and the mounting plate 3 are sequentially mounted at the end of the robotic arm of the six-axis industrial robot 1. The laser rangefinder 6 and the torch mounting bracket 4 are horizontally mounted side-by-side on the mounting plate 3. The torch 5 is mounted on the torch mounting bracket 4. The optical axis 11 is vertically mounted on the side of the torch mounting bracket 4 facing away from the laser rangefinder 6. The photo recognition camera 8 is mounted on the optical axis 11 via the camera mounting bracket 7. The pen-tube camera 10 is mounted on the optical axis 11 via the camera mounting bracket 9, and the pen-tube camera 10 is located outside the photo recognition camera 8.

[0048] In this embodiment, a six-axis industrial robot drives the movement of a cutting torch, a laser rangefinder, a photo recognition camera, and a pen-tube camera. The cutting torch cuts the old railway freight car body. The laser rangefinder performs ultra-precise positioning of the plate to be cut on the old railway freight car body, achieving precise cutting of the plate. The photo recognition camera determines the cutting path of the plate to be cut. The pen-tube camera is used to observe the wear changes and working conditions on the surface of the plate to be cut, so as to adjust the gas flow on the oxygen pipe and gas pipe to ensure cutting quality and achieve the goal of saving fuel.

[0049] See Figure 2 The cutting torch mounting frame 4 includes a U-shaped reed 4-1 and two fixing blocks 4-2. The U-shaped reed 4-1 is mounted on the mounting plate 3 by screws. The upper and lower sides of the U-shaped reed 4-1 are respectively equipped with semi-circular notches. Each fixing block 4-2 has a semi-circular notch. The semi-circular notch on each fixing block 4-2 is opposite to the semi-circular notch on the U-shaped reed 4-1, and the two are connected by screws. The cutting torch 5 is vertically installed in the notch between the U-shaped reed 4-1 and the two fixing blocks 4-2.

[0050] See Figure 2 The front end of the laser rangefinder 6 is equipped with a glass protective cover to prevent the metal shavings from flying off during vehicle body cutting from damaging the sensor body.

[0051] See Figure 2The camera mounting bracket 7 has the same structure as the camera mounting bracket 9. Taking the camera mounting bracket 7 as an example, the camera mounting bracket 7 includes a crab claw clamp 7-1, two universal joint support rods 7-2, and an adjusting stud 7-3. Both ends of the universal joint support rods 7-2 are spherical universal joints. One end of one universal joint support rod 7-2 is fixed to the crab claw clamp 7-1, and the other end of one universal joint support rod 7-2 is connected to one end of the other universal joint support rod 7-2. The spherical universal joints of the two are connected and are fastened by the adjusting stud 7-3. The other end of the other universal joint support rod 7-2 is connected to the photo recognition camera 8. The crab claw clamp 7-1 is clamped on the optical axis 11.

[0052] The image recognition camera 8 is held on the optical axis 11 by the crab claw clamp 7-1. The relative position between the image recognition camera 8 and the cutting torch 5 remains unchanged. During operation, the five axes of the industrial robot rotate 90° counterclockwise so that the image recognition camera is horizontally facing the side wall of the vehicle body and in the same direction as the cutting torch. After taking a picture of the pre-set digital image on the vehicle body, the data is directly transmitted to the robot, and then the corresponding cutting program is called, and the cutting torch then performs the cutting.

[0053] The pen-shaped camera 10 is clamped on the optical axis 11 by the crab claw clamp 7-1. The relative position of the pen-shaped camera 10 and the cutting torch 5 is fixed. The direction of the pen-shaped camera 10 is adjusted in advance by the universal joint so that it can see the actual working position of the cutting torch 5. The pen-shaped camera 10 is used to observe the changes in wear on the surface of the plate to be cut and to determine the changes in the thickness of the plate along the cutting path.

[0054] See Figure 2 An L-shaped rod 12 is also installed on the optical axis 11 for guiding and gathering the power cord.

[0055] In this embodiment, the angle and position of the cutting torch 5 are adjusted by the angle of each joint of the six-axis industrial robot 1, so that it is in the final cutting position. The movement of the cutting torch 5 is driven by the overall movement of the six-axis industrial robot 1, so as to realize the cutting of the old railway freight car body.

[0056] This application provides an automatic cutting method for used railway freight car body panels, and the specific operation steps are as follows:

[0057] Step 1: Pre-calibrate the position of the laser point generated by the laser range sensor 6 on the six-axis industrial robot 1 and the distance between the cutting nozzle of the torch 5, including the horizontal distance and the vertical distance. The horizontal distance is the horizontal distance between the cutting nozzle of the torch 5 and the laser point, and the vertical distance is the vertical distance between the cutting nozzle of the torch 5 and the plate to be cut.

[0058] Step 2: Pre-set different cutting paths and assign a different cutting symbol to each different cutting path. The cutting symbol can be represented by numbers, letters or graphics, etc., and can be determined according to the owner's needs.

[0059] Step 3: On the cutting plate of the old railway freight car body, mark the cutting symbols by hand or by laser engraving according to the damaged area and shape of the plate.

[0060] Step 4: Use the six-axis industrial robot 1 to move the photo recognition camera 8 so that the photo recognition camera 8 is aligned with the cutting symbol on the board to be cut and takes a picture. The photo taking time is 1 second.

[0061] Step 5: Use OCR technology to identify the cutting symbol, determine the cutting path represented by the cutting symbol, and call the cutting path to send it to the six-axis industrial robot 1 and the unloading station respectively, so as to determine the walking path and unloading path of the six-axis industrial robot 1.

[0062] Step 6, coarse and fine positioning of the old railway freight car body:

[0063] Step 6.1: Along the travel direction of the old railway freight car body, the fine positioning mechanism and the coarse positioning mechanism are installed in sequence. The coarse positioning mechanism is installed on the rail, and the fine positioning mechanism is rotatably installed on one side of the rail. A certain distance is left between the coarse positioning mechanism and the fine positioning mechanism.

[0064] Step 6.2: The old railway freight car body moves along the rail toward the coarse positioning mechanism until the wheels of the old railway freight car body touch the coarse positioning mechanism and come to a stop, thus achieving coarse positioning of the old railway freight car body.

[0065] Step 6.3: Rotate the precision positioning mechanism to the upper side of the rail, and use manpower and a winch to push the old railway freight car body in the opposite direction of the train's direction of travel, so that the old railway freight car body slowly approaches the precision positioning mechanism to achieve precision positioning of the old railway freight car body.

[0066] Step 7: Determine the starting cutting point, key points of the path, and ending cutting point of the cutting path for the board to be cut:

[0067] Step 7.1: Determine the calibration positions of the laser rangefinder 6 and the plate to be cut between the X, Y, and Z axes;

[0068] Step 7.2: Establish a spatial coordinate system, determine the planned path and the starting point for positioning relative to the starting cutting point of the planned path. The starting point for positioning is the calibration point of the planned path.

[0069] Step 7.3: The six-axis industrial robot 1 drives the laser rangefinder 6 to move along the planned path and finally stop at the positioning start point of the planned path.

[0070] Step 7.4: The six-axis industrial robot 1 drives the laser rangefinder 6 to move along the X-axis toward the plate to be cut until the laser rangefinder 6 reaches the calibration position between it and the plate to be cut in the X-axis direction. The distance that the laser rangefinder 6 moves in the X-axis direction is calculated as the movement compensation amount in the X-axis direction.

[0071] Step 7.5: The six-axis industrial robot 1 drives the laser rangefinder 6 back to the positioning start point. Then, the six-axis industrial robot 1 drives the laser rangefinder 6 to move along the Y-axis towards the plate to be cut until the laser rangefinder 6 reaches the calibration position in the Y-axis direction between the laser rangefinder 6 and the plate to be cut. The distance that the laser rangefinder 6 moves in the Y-axis direction is calculated as the movement compensation amount in the Y-axis direction.

[0072] Step 7.6: The six-axis industrial robot 1 drives the laser rangefinder 6 back to the positioning start point. Then, the six-axis industrial robot 1 drives the laser rangefinder 6 to move along the Z-axis towards the plate to be cut until the laser rangefinder 6 reaches the calibration position between the laser rangefinder 6 and the plate to be cut in the Z-axis direction. The distance that the laser rangefinder 6 moves in the Z-axis direction is calculated as the Z-axis movement compensation amount.

[0073] Step 7.7: Add the movement compensation amounts in the X-axis, Y-axis and Z-axis directions to the starting cutting point, key points of the path and the ending cutting point of the planned path of the six-axis industrial robot to ensure the accuracy of the cutting path of the plate to be cut.

[0074] Step 8: Use the six-axis industrial robot 1 to move the laser rangefinder 6 directly above the marked position of the board to be cut, and use the laser rangefinder 6 to emit a laser vertically towards the board to be cut, so that a laser spot is generated on the board to be cut.

[0075] Step 9: The six-axis industrial robot 1 moves along the cutting path and simultaneously drives the laser rangefinder 6, the cutting torch 5 and the pen-tube camera 10 to move. The pen-tube camera 10 is used to observe the changes in wear on the surface of the plate to be cut, determine the changes in the thickness of the plate on the cutting path, and adjust the flow rate of the gas flow detection controller on the oxygen pipe and the gas pipe, thereby adjusting the length of the air duct to ensure cutting quality and achieve the purpose of saving fuel.

[0076] Step 10: For the next piece of the old railway freight car body to be cut, repeat steps 3 to 9 until all the pieces of the old railway freight car body to be cut are cut off.

[0077] Step 11: Weld the new replacement sheet metal cut from the cutting station to the corresponding position on the old railway freight car body.

[0078] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A cutting method for an automatic cutting system for used railway freight car body panels, wherein the automatic cutting system for used railway freight car body panels includes a six-axis industrial robot (1), a torch mounting frame (4), a torch (5), a laser rangefinder (6), a camera mounting bracket (7), a photo recognition camera (8), a camera mounting bracket (9), a pen-tube camera (10), and an optical axis (11); the torch (5) is mounted on the end of the robotic arm of the six-axis industrial robot (1) via the torch mounting frame (4), the laser rangefinder (6) is mounted on one side of the torch (5), the optical axis (11) is mounted on the other side of the torch (5), the photo recognition camera (8) is mounted on the optical axis (11) via the camera mounting bracket (7), the pen-tube camera (10) is mounted on the optical axis (11) via the camera mounting bracket (9), and the pen-tube camera (10) is located outside the photo recognition camera (8); Its features are, The specific operating steps are as follows: Step 1: Pre-calibrate the position of the laser point generated by the laser rangefinder (6) on the six-axis industrial robot (1) and the distance between the cutting nozzle of the torch (5); Step 2: Pre-set different cutting paths and assign a different cutting symbol to each different cutting path. The cutting symbol can be represented by numbers, letters or graphics, and can be determined according to the owner's needs. Step 3: On the cutting plate of the old railway freight car body, mark the cutting symbols by hand or by laser engraving according to the damaged area and shape of the plate. Step 4: Use a six-axis industrial robot (1) to move the photo recognition camera (8) so that the photo recognition camera (8) is aligned with the cutting symbol on the board to be cut and takes a picture. The photo taking time is 1 second. Step 5: Use OCR technology to identify the cutting symbol, determine the cutting path represented by the cutting symbol, and call the cutting path to send it to the six-axis industrial robot (1) and the unloading station respectively, so as to determine the walking path and unloading path of the six-axis industrial robot (1); Step 6, coarse and fine positioning of the old railway freight car body; the specific positioning method is as follows: Step 6.1: Along the travel direction of the old railway freight car body, the fine positioning mechanism and the coarse positioning mechanism are installed in sequence. The coarse positioning mechanism is installed on the rail, and the fine positioning mechanism is rotatably installed on one side of the rail. A certain distance is left between the coarse positioning mechanism and the fine positioning mechanism. Step 6.2: The old railway freight car body moves along the rail toward the coarse positioning mechanism until the wheels of the old railway freight car body touch the coarse positioning mechanism and come to a stop, thus achieving coarse positioning of the old railway freight car body. Step 6.3: Rotate the precision positioning mechanism to the upper side of the rail, and use manpower and a winch to push the old railway freight car body in the opposite direction of the train's direction of travel, so that the old railway freight car body slowly approaches the precision positioning mechanism to achieve precision positioning of the old railway freight car body. Step 7: Determine the starting cutting point, key points of the path, and ending cutting point of the cutting path for the plate to be cut; The method for determining step 7 is as follows: Step 7.1: Determine the calibration positions of the laser rangefinder (6) and the plate to be cut between the X-axis, Y-axis and Z-axis; Step 7.2: Establish a spatial coordinate system, determine the planned path and the starting point for positioning relative to the starting cutting point of the planned path. The starting point for positioning is the calibration point of the planned path. Step 7.3, the six-axis industrial robot (1) drives the laser rangefinder (6) to move along the planned path and finally stop at the starting point of the planned path; Step 7.4, the six-axis industrial robot (1) drives the laser range sensor (6) to move along the X-axis towards the plate to be cut until the laser range sensor (6) reaches the calibration position between the laser range sensor (6) and the plate to be cut in the X-axis direction. The distance moved by the laser range sensor (6) in the X-axis direction is calculated as the movement compensation amount in the X-axis direction. Step 7.5: The six-axis industrial robot (1) drives the laser rangefinder (6) back to the starting point of the positioning. Then, the six-axis industrial robot (1) drives the laser rangefinder (6) to move along the Y-axis towards the plate to be cut until the laser rangefinder (6) reaches the calibration position in the Y-axis direction between the laser rangefinder (6) and the plate to be cut. The distance that the laser rangefinder (6) moves in the Y-axis direction is calculated as the movement compensation amount in the Y-axis direction. Step 7.6, the six-axis industrial robot (1) drives the laser range sensor (6) back to the starting point of the positioning. Then the six-axis industrial robot (1) drives the laser range sensor (6) to move along the Z-axis towards the plate to be cut until the laser range sensor (6) reaches the calibration position between the laser range sensor (6) and the plate to be cut in the Z-axis direction. The distance moved by the laser range sensor (6) in the Z-axis direction is calculated as the movement compensation amount in the Z-axis direction. Step 7.7: Add the movement compensation amounts in the X-axis, Y-axis and Z-axis directions to the starting cutting point, key points of the path and the ending cutting point of the planned path of the six-axis industrial robot to ensure the accuracy of the cutting path of the plate to be cut. Step 8: Use a six-axis industrial robot (1) to move the laser range sensor (6) directly above the calibrated position of the plate to be cut, and use the laser range sensor (6) to emit a laser vertically towards the plate to be cut, so that a laser point is generated on the plate to be cut. Step 9: The six-axis industrial robot (1) moves along the cutting path and simultaneously drives the laser rangefinder (6), the torch (5) and the pen-tube camera (10) to move. The pen-tube camera (10) is used to observe the wear changes on the surface of the plate to be cut, determine the changes in the plate thickness on the cutting path, and adjust the flow rate of the gas flow detection controller on the oxygen pipe and the gas pipe, thereby adjusting the length of the air line to ensure the cutting quality and achieve the purpose of saving fuel. Step 10: For the next piece of the old railway freight car body to be cut, repeat steps 3 to 9 until all the pieces of the old railway freight car body to be cut are cut off. Step 11: Weld the new replacement sheet metal cut from the cutting station to the corresponding position on the old railway freight car body.

2. The cutting method of the automatic cutting system for used railway freight car body plates according to claim 1, characterized in that: In step 1, the distance between the laser point generated by the laser ranging sensor (6) and the cutting nozzle of the torch (5) includes a horizontal distance and a vertical distance. The horizontal distance is the horizontal distance between the cutting nozzle of the torch (5) and the laser point, and the vertical distance is the vertical distance between the cutting nozzle of the torch (5) and the plate to be cut.

3. The cutting method of the automatic cutting system for used railway freight car body panels according to claim 1, characterized in that: An anti-collision sensor (2) and a mounting plate (3) are also provided between the cutting torch (5) and the end of the six-axis industrial robot (1) arm. The anti-collision sensor (2) is located between the end of the six-axis industrial robot (1) arm and the mounting plate (3). The laser rangefinder (6) and the cutting torch mounting bracket (4) are mounted side by side on the mounting plate (3).

4. The cutting method of the automatic cutting system for used railway freight car body plates according to claim 1, characterized in that: The cutting torch mounting frame (4) includes a U-shaped reed (4-1) and two fixing blocks (4-2). The U-shaped reed (4-1) is mounted on the mounting plate (3) by screws. The upper and lower sides of the U-shaped reed (4-1) are respectively equipped with semi-circular notches. Each fixing block (4-2) has a semi-circular notch. The semi-circular notch on each fixing block (4-2) is opposite to the semi-circular notch on the U-shaped reed (4-1), and the two are connected by screws. The cutting torch (5) is vertically installed in the notch between the U-shaped reed (4-1) and the two fixing blocks (4-2).

5. The cutting method of an automatic cutting system for used railway freight car body panels according to claim 1, characterized in that: The front end of the laser rangefinder (6) is fitted with a glass protective cover.

6. The cutting method of an automatic cutting system for used railway freight car body panels according to claim 1, characterized in that: The camera mounting bracket (7) has the same structure as the camera mounting bracket (9). The camera mounting bracket (7) includes a crab claw clamp (7-1), two universal joint rods (7-2) and an adjusting stud (7-3). Both ends of the universal joint rods (7-2) are spherical universal joints. One end of one universal joint rod (7-2) is fixed on the crab claw clamp (7-1). The other end of one universal joint rod (7-2) is connected to one end of the other universal joint rod (7-2), and the spherical universal joints of the two are connected and fastened by the adjusting stud (7-3). The other end of the other universal joint rod (7-2) is connected to the photo recognition camera (8). The crab claw clamp (7-1) is clamped on the optical axis (11).

7. The cutting method of an automatic cutting system for used railway freight car body panels according to claim 1, characterized in that: An L-shaped rod (12) is also installed on the optical axis (11).

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