Railway sleeper-oriented double-robot laser cutting system and method

Abstract

The present application relates to the technical field of sleeper cutting, and discloses a double-robot laser rebar cutting method for railway sleepers, which comprises the following steps: moving a line laser sensor mounted at the tail end of an industrial robot to a preset first measuring position, so that the measuring range of the line laser sensor covers the joint area of the upper surface and the first side surface of the sleeper, collecting two-dimensional contour point clouds, extracting four feature points P1, P2, P3 and P4 in the two-dimensional contour point clouds, generating an initial workpiece coordinate system B0 under the robot base coordinate system, the origin of the coordinate system being located on an auxiliary plane, and the Z-axis direction of the coordinate system being directed from P4 to the foot point of P4 on the auxiliary plane, and under the initial workpiece coordinate system B0, teaching and storing a motion path program of the robot driving the laser cutting gun to cut the rebar in each row and each column between sleepers. The present application provides a double-robot laser rebar cutting system and method for railway sleepers, and can improve the overall production efficiency.

Description

Technical Field

[0001] This invention relates to the field of railway sleeper cutting technology, and in particular to a dual-robot laser rib-cutting system and method for railway sleepers. Background Technology

[0002] Reinforced concrete sleepers are widely used in railway construction. These sleepers are characterized by their hard surface, long service life, good track stability, and ability to meet the requirements of high speed and high capacity transport. Reinforced concrete sleepers are manufactured by injecting concrete mixture into a long mold containing reinforcing bars and fittings. Typically, two rows are produced side-by-side, with 4-5 sleepers per row, each 2.5-2.6 meters long. The reinforcing bars of the sleepers in the same row are connected together, and a gap of 40-60 mm is left between adjacent sleepers in the same row. After demolding, the high-strength threaded reinforcing bars between adjacent sleepers need to be cut to form a complete concrete sleeper product. Generally, each sleeper contains 10-14 high-strength threaded reinforcing bars, arranged in three or four rows laterally and three or four columns longitudinally. Only by cutting the multiple rows and columns of reinforcing bars between adjacent sleepers after demolding can a complete concrete sleeper product be formed.

[0003] Previously, two common methods were used to cut the reinforcing bars between railway sleepers: manual cutting and automated cutting. Manual cutting suffers from high labor costs, low automation levels, significant health hazards during the process, and low efficiency. Automated cutting typically uses cutters or saw blades to cut or saw the reinforcing bars, but this method suffers from high cutting noise, rapid wear of the cutters / saw blades, and while more efficient than manual cutting, it is still relatively inefficient. Currently, the trend in railway sleeper rebar cutting technology is laser cutting. Compared to traditional cutting processes, laser cutting offers advantages such as high speed, narrow kerf, and a small heat-affected zone. However, because there is only a 40-60 mm gap between adjacent sleepers, while the reinforcing bars to be cut are in multiple rows and columns, and the sleepers are not fixed in position when transported to the cutting location, they may shift in various directions within the plane. Therefore, a standalone laser cutting gun cannot cut multiple rows and columns of rebar with variable positions. Currently, feasible laser cutting solutions all involve a robot carrying the laser cutting gun, using external auxiliary positioning methods to achieve the railway sleeper rebar cutting operation. However, such auxiliary positioning methods rely on external references (such as mechanical stops, calibration plates, etc.), and the geometric relationship between the positioning reference and the steel bar to be cut is not direct enough. The positioning accuracy is limited by the installation accuracy of the auxiliary device. When the sleeper has a random positional shift on the conveyor line, the adaptability of the auxiliary positioning method is limited, and it is difficult to achieve high-precision and high-robust position correction. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a dual-robot laser skewing system and method for railway sleepers, which can improve overall production efficiency.

[0005] This invention provides a dual-robot laser rebar cutting method for railway sleepers, used to cut rebar in the gap between adjacent sleepers, including the following steps: Collect the two-dimensional contour point cloud of the upper surface and the first side of the sleeper, and extract the inflection point P1 of the first side edge and the reference point P2 of the upper surface; the first side is the inclined plane connecting the upper surface of the sleeper and the vertical plane where the steel bars are inserted between the sleepers, and the first side edge is the intersection line of the upper surface and the first side. The first side edge inflection point P1 is translated along the first side edge to obtain inflection point P3; Collect the contour data of the top area of ​​the steel bar to be cut, and extract the highest point P4 of the steel bar from it; Based on the extracted coordinates of P1, P2, P3, and P4 in the robot base coordinate system, an initial workpiece coordinate system B0 is calculated and generated. Under the initial workpiece coordinate system B0, the steel bars between the sleepers are cut, the motion trajectory of the robot driving the laser cutting gun to cut the steel bars is recorded, and the cutting path program is generated and stored. For each sleeper subsequently delivered to the cutting station, the robot is controlled to repeatedly perform measurement actions to obtain new feature points P1', P2', P3', and P4' corresponding to the current sleeper; Using the same geometric constraint calculation method, a new workpiece coordinate system B0' is generated based on the new feature points; Switch the reference coordinate system of the stored laser cutting path program from the initial workpiece coordinate system B0 to the new workpiece coordinate system B0'; The robot is controlled to execute the cutting path program in the updated workpiece coordinate system B0' to complete the cutting operation of the current sleeper.

[0006] Furthermore, the calculation and generation of the initial workpiece coordinate system B0, based on the geometric constraints of the sleeper, specifically includes: Use P1 and P3 to determine a direction vector, and normalize this vector to use as the X-axis of the workpiece coordinate system B0. The direction of this X-axis is parallel to the length direction of the sleeper. Using points P1, P2, and P3, fit the plane P containing the upper surface of the sleeper. up ; Construct an auxiliary plane P that simultaneously satisfies the following two conditions side : Passing through points P1 and P3; plane P of the upper surface of the sleeper up Perpendicular to the auxiliary plane P side Parallel to the side of the sleeper; Calculate the distance from P4 to the auxiliary plane P. side The foot of the perpendicular P 4⊥The foot of the perpendicular is taken as the origin of the workpiece coordinate system B0; Will point from P4 to P 4⊥ The normalized direction vector is used as the Z-axis of the workpiece coordinate system B0, and the direction of the Z-axis is perpendicular to the auxiliary plane P. side , pointing to the highest point of the reinforcing bar; The cross product of the X-axis direction vector and the Z-axis direction vector yields the Y-axis of the workpiece coordinate system B0.

[0007] Furthermore, the extraction of the first side edge inflection point P1 and the upper surface reference point P2 is specifically as follows: A line laser sensor scans the area where the upper surface of the sleeper intersects with the first side surface to obtain a two-dimensional contour line composed of multiple discrete points. A straight-line fitting algorithm is used to fit the contour line to obtain the line segments representing the upper surface and the line segments representing the side surface, respectively. Calculate the intersection of the two fitted line segments and take this intersection as the first side edge inflection point P1; On the fitted line segment representing the upper surface, select a point at a preset distance from P1 as the reference point P2 for the upper surface.

[0008] Furthermore, the specific method for extracting the highest point P4 of the reinforcing bar is as follows: A line laser sensor scans the top area of ​​the outermost steel bar to be cut to obtain a two-dimensional contour point cloud of the steel bar surface; Peak detection is performed on the contour point cloud, and the point with the largest ordinate value is selected as the highest point P4 of the rebar.

[0009] Furthermore, it also includes hand-eye alignment steps: The standard sphere is fixed within the measurable range of the laser sensor; The robot is controlled to move to multiple different poses, so that the line laser sensor measures the standard ball from different directions. Each measurement yields the coordinates of the center of the standard ball in the line laser sensor coordinate system. Based on the pose of the robot flange in the robot base coordinate system during each measurement, and combined with the constraint that the position of the center of the standard sphere remains unchanged in the robot base coordinate system, a system of equations is solved to obtain the rotation and translation matrices from the line laser sensor coordinate system to the robot end-effector coordinate system.

[0010] Furthermore, switching the reference coordinate system of the stored laser cutting path program to the new workpiece coordinate system specifically involves: Read the coordinate values ​​of each teaching point in the initial workpiece coordinate system B0 from the stored cutting path program; The coordinate values ​​of each teaching point are transformed to the new workpiece coordinate system B0' through coordinate transformation relationship, and the updated cutting path program is generated. Alternatively, the parameters of the currently active workpiece coordinate system in the robot control system can be directly modified so that the original cutting path program is reinterpreted and executed in the new workpiece coordinate system.

[0011] A dual-robot laser beam cutting system for railway sleepers, used to implement a dual-robot laser beam cutting method for railway sleepers, comprising: Two industrial robots are symmetrically arranged on both sides of the cutting station, with each robot's working range covering the gap between the sleepers on one side. Line laser sensors are fixedly installed at the end of the flange of each industrial robot to collect contour data of the sleeper edge, the upper surface of the sleeper, and the top of the reinforcing bar at three preset measurement positions. Laser cutting guns are installed as end-effectors on the ends of various industrial robots for laser cutting of steel bars. The control unit, electrically connected to two industrial robots, a line laser sensor, and a laser cutting gun, is configured as follows: Controlling industrial robots to perform measurement actions; Multiple feature points are extracted from the measured contour data, and the initial workpiece coordinate system is calculated according to the geometric constraint method. During the initial calibration, the taught cutting path program is stored; During batch operations, the initial workpiece coordinate system in the cutting path program is replaced with the recalculated workpiece coordinate system, and the robot is controlled to execute the updated program to complete the cutting.

[0012] Furthermore, the control unit also achieves collaborative control of the two robots in the following ways: In the system software, set independent operation status variables for each robot and set program synchronization points; After completing the task of the current stage, each robot sends a completion signal to the other robot through internal variables; Only when the internal variables of both robots confirm that the current stage of the task has been completed will the control unit allow the two robots to simultaneously enter the next stage of the task.

[0013] Furthermore, the control unit is also used to perform hand-eye calibration during the initial installation of the system.

[0014] Compared with the prior art, the technical solution provided by this invention has the following advantages: This invention automatically constructs a workpiece coordinate system by rapidly extracting the inflection points of the two sides of the sleeper's edges, the reference point on the upper surface, and the highest point of the outermost rebar to be cut from three preset positions. A new coordinate system is then remeasured and generated when each sleeper arrives, enabling the cutting path program to accurately adapt to arbitrary planar offsets and posture changes of the sleeper, completely eliminating the limitations of mechanical positioning fixtures. Simultaneously, by using a robot carrying a laser cutting gun, the cutting path for all rows and columns of rebars is taught once in the initial coordinate system. Subsequent sleepers only need to dynamically switch coordinate systems to reuse this path, completely solving the problem of multi-target cutting in narrow gaps. This fully leverages the advantages of laser cutting—high speed, narrow kerf, small heat-affected zone, low noise, and no consumable waste—eliminating the health hazards of manual rebar cutting and achieving flexible automated operation of "one-time teaching, batch application," significantly improving rebar cutting efficiency and quality. Attached Figure Description

[0015] Figure 1 A three-dimensional schematic diagram of a dual-robot laser severing device for railway sleepers provided in an embodiment of the present invention; Figure 2 An axonometric view of a dual-robot laser rebar cutting device for railway sleepers provided in an embodiment of the present invention; Figure 3 A flowchart illustrating the initial preparation process of a dual-robot laser skewing method for railway sleepers provided in an embodiment of the present invention. Figure 4 A formal rebar cutting operation flowchart for a dual-robot laser rebar cutting method for railway sleepers provided in an embodiment of the present invention; Figure 5 A flowchart illustrating the collaborative operation of a dual-robot laser tendon rupture system provided in this embodiment of the invention; Figure 6 This is a schematic diagram of the first measurement position provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of the second measurement position provided in an embodiment of the present invention; Figure 8 This is a schematic diagram of the third measurement position provided in an embodiment of the present invention. Detailed Implementation

[0016] The following detailed description of a specific embodiment of the present invention is provided in conjunction with the accompanying drawings. However, it should be understood that the scope of protection of the present invention is not limited to the specific embodiment.

[0017] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the technical solution of this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0018] The present invention will be described below through several specific embodiments. To keep the following description of the embodiments clear and concise, detailed descriptions of known functions and components may be omitted. When any component of an embodiment of the present invention appears in more than one drawing, the component may be represented by the same reference numerals in each drawing.

[0019] Figure 1 This is a three-dimensional schematic diagram of a dual-robot laser beam cutting device for railway sleepers, provided as an embodiment of the present invention. Figure 2 This is an axonometric view of a dual-robot laser-assisted rebar cutting device for railway sleepers, provided in an embodiment of the present invention. Figure 3 This is a flowchart illustrating the initial preparation process of a dual-robot laser skewing method for railway sleepers, as provided in an embodiment of the present invention. Figure 4 This is a flowchart illustrating the formal rebar cutting operation of a dual-robot laser rebar cutting method for railway sleepers, provided in an embodiment of the present invention. Figure 5 This invention provides a flowchart of a collaborative operation of a dual-robot laser tendon rupture system. Figure 6 This is a schematic diagram of the first measurement position provided in an embodiment of the present invention. Figure 7 This is a schematic diagram of the second measurement position provided in an embodiment of the present invention. Figure 8 This is a schematic diagram of the third measurement position provided in an embodiment of the present invention.

[0020] like Figure 1 and Figure 2 As shown, this embodiment of the invention provides a dual-robot laser skewing system and method for railway sleepers. A line laser sensor is fixedly installed at the end of the robot flange, and then robot hand-eye calibration is performed to ensure that the data measured by the line laser can be converted to the robot base coordinate system according to the results of the hand-eye calibration, so as to obtain the coordinate position of the measured line laser point relative to the center point of the robot base.

[0021] Specifically, the robot hand-eye calibration method is as follows: A standard sphere is fixedly placed within the measurable range of a line laser sensor on the robot's end effector. At this time, the position of the standard sphere's center relative to the robot's base coordinate system remains unchanged. The center of the standard sphere is then set in the robot coordinate system. The coordinates below and their online laser sensor coordinate system The coordinates in the equation satisfy the following equation:

[0022] (1), in For the center of the ball to be fixed at Coordinates in coordinate system , For the center of the ball to be fixed at Coordinates in coordinate system , 、 Let be the rotation and translation matrices from the robot's end-effector coordinate system to the robot's base coordinate system. 、 Let the rotation and translation matrices be the coordinates from the line laser sensor coordinate system to the robot end-effector coordinate system. Let be the homogeneous transformation matrix from the robot's end-effector coordinate system to the robot. This is the homogeneous transformation matrix from the line laser sensor coordinate system to the robot end-effector coordinate system.

[0023] Expanding equation (1) yields: (2), The robot, carrying a line laser sensor, illuminates a standard sphere as shown in the diagram above, thus determining the center of the cross-section of the sphere under the laser plane. Coordinates in coordinate system And the radius r of the circle at that cross-section. According to the properties of a sphere, the center of a standard sphere... The projection onto the plane of the cross-section circle and the center of the cross-section circle The centers of the cross-section circles coincide, so the center of the cross-section circles is... X and Z axis coordinates relative to the center of the standard sphere Their X and Z axis coordinates are the same, that is ,and At the same time, the center of the standard ball exist The Y-axis coordinate in the coordinate system can be represented as:

[0024] (3), In the formula, R is the radius of the standard sphere, and r is the radius of the cross-sectional circle. Thus, through fitting and calculation, the center of the standard sphere in the coordinate system is obtained. coordinates below .

[0025] By changing the pose of the robotic arm, multiple measurements are performed on a standard ball. Since the position of the standard ball relative to the robot's base coordinate system remains constant, the multiple measurements of the standard ball obtained from each measurement by the line laser sensor are calculated. The coordinates of the sphere's center in the coordinate system should theoretically be equal. During each measurement, the robot flange is recorded in the measurement pose. The XYZABC values ​​in the coordinate system (i.e.) 、 ), and the center of the ball at each measurement coordinate system After multiple measurements, based on the principle that the theoretical values ​​of the sphere's center are equal, and combined with Equation 2, the following system of equations can be derived:

[0026] (4), In the formula, and Solving for the i-th and (i+1)-th measurements respectively. The coordinates of the sphere's center in the coordinate system, with the upper right subscript (i) representing the i-th measurement.

[0027] After obtaining multiple sets of equations (4) through multiple measurements, the final rotation transformation matrix from the robot flange to the origin of the laser coordinate system can be obtained by using matrix calculation algorithms. 、 This completes the hand-eye calibration of the line laser sensor.

[0028] The robot's position was adjusted using a handheld device so that the line laser sensor could measure the slope data on one side of the sleeper. The robot's position was then adjusted again so that the line laser could measure the slope on the other side of the sleeper. Finally, the position was adjusted once more so that the line laser could measure the location of the first layer of reinforcing steel.

[0029] Based on the above measurement data, the positional relationship between the middle steel bars of the two sleepers and the robot base is calculated.

[0030] Set the workpiece coordinate system according to the pose relationship obtained at this time, switch the robot tool to the end laser cutting gun, and set the laser cutting gun as the tool coordinate system.

[0031] Using this tool and workpiece coordinate system, we will teach how to write a program for cutting the reinforcing bars between sleepers.

[0032] After the next two sleepers arrive, the new workpiece coordinate system is measured and calculated again.

[0033] Replace the original workpiece coordinate system in the cutting action program with the new workpiece coordinate system, and restart the cutting program to complete the cutting of the steel bars between the sleepers in different current positions.

[0034] The initial system preparation workflow is as follows: Figure 3 As shown. After the entire system is installed, the sleeper to be cut is transported to the robot's working area via a roller conveyor. The robot, carrying a line laser sensor, reaches the first measurement position, where it measures two key points, P1 and P2. After measurement, the robot moves to the second measurement position and measures key point P3. After measurement, the robot moves to the third measurement position and measures key point P4. Then, using the coordinate conversion method described below, the robot workpiece coordinate system B0 for this sleeper to be cut can be calculated from these four point information. Finally, based on this workpiece coordinate system, the robot laser gun cutting program is taught and written. At this point, the system preparation is complete.

[0035] The algorithm for determining the robot workpiece coordinate system using the four-point method is described as follows: First, the robot moves the laser sensor to the first measurement position, such as... Figure 6 As shown, the inflection point of the edge of the upper surface of the sleeper can be measured using a laser sensor. Points on the upper surface of the sleeper The specific calculation method is implemented by the sensor's built-in algorithm (most sensors have this function): The basic principle can be understood as using principal component analysis to fit two straight lines based on the measured points. One line lies on the vertical plane of the graph, and the other line lies on the inclined plane. The intersection point of the two lines is then calculated. , It can then be defined as distance. A random surface point at a fixed distance along the X-direction of the laser sensor.

[0036] Then, the laser sensor is moved to the second measurement point. Figure 7 As shown, and by measuring again, the inflection point of the edge of the upper surface of the sleeper can be measured. .Will And it can be used as the X-axis of the coordinate system by unit vectorization. Then use , The equation of the plane of the upper surface of the sleeper can be obtained by considering the coplanar relationship of the three points. Then, by utilizing the relationship that the vertical side of the sleeper is perpendicular to the top surface, the distance parallel to the side of the sleeper and passing through... , The parallel plane of the vertical plane of the sleepers at these two points The specific algorithm is described as follows: Because plane passes through ,therefore The vector is a vector in the plane, due to the upper surface The normal vector is Using a plane The normal vector and ( Vector and upper surface normal vector At the same time, the perpendicular relationship, the plane The normal vector can be obtained from Calculated. planar Thus far... All four unknowns of the plane equation have been solved.

[0037] Finally, move the sensor to the third measurement point. Figure 8 The coordinates of the highest point on the surface of the reinforcing bar at the rightmost edge were measured. ,use Point and plane equations Points can be obtained exist Plane projection The coordinates. Thus, with Pointed As the origin of the workpiece coordinate system B0. The direction of the B0X axis in the workpiece coordinate system is used as... point to As the Z-axis The Y-axis direction is At this point, the origin of the workpiece coordinate system B0 is... The coordinate system orientation is This can be used as the initial workpiece coordinate system for laser cutting teaching programming. .

[0038] Specifically, during sleeper production, the cylindrical conveyor simultaneously transports two parallel rows of sleepers connected by steel bars to the dual-robot laser rebar cutting system's workstation. To meet the cycle time requirements of the laser rebar cutting station, two robots are used for synchronous rebar cutting to improve sleeper production efficiency. The single-robot laser rebar cutting operation process is as follows: Figure 4 As shown. To ensure the coordination and safety of the dual-robot laser tendon cutting operation, the laser tendon cutting system uses software to synchronize the position measurement and laser cutting actions of the two robots. The collaborative operation process of the dual-robot laser tendon cutting system is as follows: Figure 5 As shown. To ensure equipment safety, the dual-robot laser shank cutting system uses program synchronization points set in the system software to ensure that both robots are always simultaneously engaged in either the cutting coordinate system measurement process or the laser shank cutting operation. The working status of the two robots has independent variables in the software system and is protected by logic. Subsequent measurement or cutting operations can only proceed after both robots have completed their independent processes and mutually confirmed through internal program variables.

[0039] Specifically, the sleepers connected by two steel bars are molded by the mold-making machine at the previous station and then placed on the roller conveyor. During the mold-making process, it is ensured that the two sleepers are basically parallel to the roller conveyor, and their tilt will not exceed 2°. The cutting position between the two adjacent sleepers will also be on the same parallel line perpendicular to the roller conveyor. There is only a deviation of ±20mm along the direction of the roller conveyor and perpendicular to the position of the roller conveyor at the stopping position. All deviations are within the detection range of the line laser sensor. The positional relationship between the projection point (the origin of the coordinate system) and the rebar to be cut is relatively fixed. Although the sleeper changes in the XY direction of the roller conveyor plane or even in the Z plane perpendicular to XY, the relative position between this projection point and the rebar remains unchanged each time.

[0040] Since the cutting program is taught relative to this point (this coordinate system), if this point is adjusted, for example, if this point moves forward 2mm along the conveyor direction of the roller conveyor, then the position of the rebar also moves forward 2mm, and all the cutting points also move forward 2mm accordingly, so that the rebar can still be cut correctly.

[0041] Because after each sleeper is in place, the above ~ The points themselves will change, but their positional relationships remain unchanged. Therefore, after the first measurement, an initial workpiece coordinate system B0 is generated. Based on this coordinate system, the laser cutting action is taught. After the sleepers are in place, the workpiece coordinate system B0' is updated, and the positions of each point on the taught action are automatically updated. This enables the automatic relative movement of the cutting action path between sleepers, ensuring the smooth cutting of the reinforcing bars.

[0042] The formal rebar severance procedure of the system is as follows: Figure 6 As shown.

[0043] Once the system preparation is complete, the formal laser-assisted screed cutting operation begins. At this point, the sleeper to be cut is transported to the cutting position via a roller conveyor. The robot, carrying a line laser sensor, reaches the first measurement position, where two key points, P1 and P2, are measured. After measurement, the robot moves to the second measurement position and measures key point P3. After that, the robot moves to the third measurement position and measures key point P4. The updated robot coordinates are then obtained using the coordinate calculation method described above. The robot then re-invokes the pre-programmed laser cutting program, and automatically completes the laser cutting of the sleeper reinforcement in the current coordinate system. After cutting is complete, a new sleeper is delivered by a roller conveyor, and the above steps can be repeated to achieve continuous laser cutting of sleeper reinforcement.

[0044] The above inventions are merely a few specific embodiments of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A dual-robot laser rebar cutting method for railway sleepers, used to cut rebar in the gap between adjacent sleepers, characterized in that, Includes the following steps: Two-dimensional contour point clouds of the upper surface and the first side surface of the sleeper are collected, and the inflection point P1 of the first side edge and the reference point P2 of the upper surface are extracted from them; the first side surface is the inclined surface connecting the upper surface of the sleeper and the vertical plane where the steel bars are inserted between the sleepers, and the first side edge is the intersection line of the upper surface and the first side surface. The first side edge inflection point P1 is translated along the first side edge to obtain inflection point P3; Collect the contour data of the top area of ​​the steel bar to be cut, and extract the highest point P4 of the steel bar from it; Based on the extracted coordinates of P1, P2, P3, and P4 in the robot base coordinate system, an initial workpiece coordinate system B0 is calculated and generated. Under the initial workpiece coordinate system B0, the steel bars between the sleepers are cut, the motion trajectory of the robot driving the laser cutting gun to cut the steel bars is recorded, and the cutting path program is generated and stored. For each sleeper subsequently delivered to the cutting station, the robot is controlled to repeatedly perform measurement actions to obtain new feature points P1', P2', P3', and P4' corresponding to the current sleeper; Using the same geometric constraint calculation method, a new workpiece coordinate system B0' is generated based on the new feature points; Switch the reference coordinate system of the stored laser cutting path program from the initial workpiece coordinate system B0 to the new workpiece coordinate system B0'; The robot is controlled to execute the cutting path program in the updated workpiece coordinate system B0' to complete the cutting of the reinforcing bars of the current sleeper.

2. The dual-robot laser skewing method for railway sleepers as described in claim 1, characterized in that, The calculation of the initial workpiece coordinate system B0 based on the geometric constraints of the sleeper specifically includes: A direction vector is determined using P1 and P3. This vector is normalized and used as the X-axis of the workpiece coordinate system B0. The direction of this X-axis is parallel to the length direction of the sleeper. Using points P1, P2, and P3, fit the plane P containing the upper surface of the sleeper. up ; Construct an auxiliary plane P that simultaneously satisfies the following two conditions side : Passing through points P1 and P3; plane P of the upper surface of the sleeper up Perpendicular to the auxiliary plane P side Parallel to the side of the sleeper; Calculate the distance from P4 to the auxiliary plane P. side foot of the perpendicular P 4⊥ The foot of the perpendicular is taken as the origin of the workpiece coordinate system B0; Will point from P4 to P 4⊥ The normalized direction vector is used as the Z-axis of the workpiece coordinate system B0, and the direction of the Z-axis is perpendicular to the auxiliary plane P. side , pointing to the highest point of the reinforcing bar; The cross product of the X-axis direction vector and the Z-axis direction vector yields the Y-axis of the workpiece coordinate system B0.

3. The dual-robot laser skewing method for railway sleepers as described in claim 1, characterized in that, The extraction of the first side edge inflection point P1 and the upper surface reference point P2 specifically involves: A line laser sensor scans the area where the upper surface of the sleeper intersects with the first side surface to obtain a two-dimensional contour line composed of multiple discrete points. A straight-line fitting algorithm is used to fit the contour line to obtain the line segments representing the upper surface and the line segments representing the side surface, respectively. Calculate the intersection of the two fitted line segments and take this intersection as the first side edge inflection point P1; On the fitted line segment representing the upper surface, select a point at a preset distance from P1 as the reference point P2 for the upper surface.

4. The dual-robot laser skewing method for railway sleepers according to claim 1, characterized in that, The specific method for extracting the highest point P4 of the reinforcing bar is as follows: A line laser sensor scans the top area of ​​the outermost steel bar to be cut to obtain a two-dimensional contour point cloud of the steel bar surface; Peak detection is performed on the contour point cloud, and the point with the largest ordinate value is selected as the highest point P4 of the reinforcing bar.

5. The dual-robot laser skewing method for railway sleepers according to claim 1, characterized in that, It also includes hand-eye calibration steps: The standard sphere is fixed within the measurable range of the laser sensor; The robot is controlled to move to multiple different poses, so that the line laser sensor measures the standard ball from different directions. Each measurement yields the coordinates of the center of the standard ball in the line laser sensor coordinate system. Based on the pose of the robot flange in the robot base coordinate system during each measurement, and combined with the constraint that the position of the center of the standard sphere remains unchanged in the robot base coordinate system, a system of equations is solved to obtain the rotation and translation matrices from the line laser sensor coordinate system to the robot end-effector coordinate system.

6. The dual-robot laser skewing method for railway sleepers according to claim 1, characterized in that, The specific steps of switching the reference coordinate system of the stored laser cutting path program to the new workpiece coordinate system are as follows: Read the coordinate values ​​of each teaching point in the initial workpiece coordinate system B0 from the stored cutting path program; The coordinate values ​​of each teaching point are transformed to the new workpiece coordinate system B0' through coordinate transformation relationship, and the updated cutting path program is generated. Alternatively, the parameters of the currently active workpiece coordinate system in the robot control system can be directly modified so that the original cutting path program is reinterpreted and executed in the new workpiece coordinate system.

7. A dual-robot laser sintering system for railway sleepers, used to implement the dual-robot laser sintering method for railway sleepers as described in any one of claims 1-6, characterized in that, include: Two industrial robots are symmetrically arranged on both sides of the cutting station, with each robot's working range covering the gap between the sleepers on one side. Line laser sensors are fixedly installed at the end of the flange of each industrial robot to collect contour data of the sleeper edge, the upper surface of the sleeper, and the top of the reinforcing bar at three preset measurement positions. Laser cutting guns are installed as end-effectors on the ends of various industrial robots for laser cutting of steel bars. The control unit, electrically connected to two industrial robots, a line laser sensor, and a laser cutting gun, is configured as follows: Controlling industrial robots to perform measurement actions; Multiple feature points are extracted from the measured contour data, and the initial workpiece coordinate system is calculated according to the geometric constraint method. During the initial calibration, the taught cutting path program is stored; During batch operations, the initial workpiece coordinate system in the cutting path program is replaced with the recalculated workpiece coordinate system, and the robot is controlled to execute the updated program to complete the cutting.

8. The dual-robot laser skewing system for railway sleepers as described in claim 7, characterized in that, The control unit also achieves dual-robot collaborative control in the following ways: In the system software, set independent operation status variables for each robot and set program synchronization points; After completing the task of the current stage, each robot sends a completion signal to the other robot through internal variables; Only when the internal variables of both robots confirm that the current stage of the task has been completed will the control unit allow the two robots to simultaneously enter the next stage of the task.

9. The dual-robot laser skewing system for railway sleepers as described in claim 7, characterized in that, The control unit is also used to perform hand-eye calibration during the initial installation of the system.

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