A welding trajectory optimization method and device for a spot welding robot

Abstract

This invention discloses a method and apparatus for optimizing the welding trajectory of a spot welding robot. The method includes: acquiring motion data of the motion axes of the spot welding robot; identifying the welding gun entry / exit actions of the spot welding robot based on the motion data, and recording the welding point coordinates corresponding to the entry / exit actions, wherein the welding point coordinates are the endpoint coordinates of the trajectory of the entry / exit action; statistically analyzing multiple welding point coordinates, selecting at least two consecutive welding point coordinates from the multiple welding point coordinates, calculating a first translation time for the welding gun movement based on the at least two consecutive welding point coordinates; and optimizing the welding trajectory using the first translation time. This invention can first acquire motion data of each axis of the spot welding robot, use the motion data to determine the entry / exit actions, and optimize the robot's trajectory based on the coordinates of the entry / exit actions, thereby reducing the entry / exit actions during the welding process, shortening welding time, and improving welding efficiency.

Description

Technical Field

[0001] This invention relates to the technical field of welding optimization, and in particular to a method and apparatus for optimizing the welding trajectory of a spot welding robot. Background Technology

[0002] Welding robots are industrial robots that perform welding. One common type of welding robot is the spot welding robot, which consists of a robot body, a computer control system, a teach pendant, and a spot welding system. It generally adopts the basic design of an articulated industrial robot and has six degrees of freedom: waist rotation, upper arm rotation, forearm rotation, wrist rotation, wrist swing, and wrist twisting, and is driven by hydraulic and electrical drives.

[0003] To improve the positioning accuracy of the weld point and avoid serious damage caused by high-speed collisions between the welding torch and the workpiece, the spot welding robot operates as follows after reaching the torch inlet position: the robot moves the torch at a relatively slow speed, clamps the welding clamp upon reaching the weld point, and performs the spot welding action. After completing the spot welding action, the spot welding robot typically exits the torch along the same path, thus completing the torch inlet and outlet action for a single weld point.

[0004] However, the commonly used methods have the following technical problems: Because a group of gun-entry and exit movements of a spot welding robot have the same path but opposite directions, and the speed decreases significantly during these movements, the movement efficiency is low. Furthermore, if the straight-line distance between the current weld point and the next weld point is less than the gun-entry / exit distance, two gun-entry / exit movements are often required between two welding sessions, increasing processing time. This is especially true when welding high-precision components, where the distance between weld points is short, often requiring a significant amount of time for gun-entry / exit movements, resulting in long welding times and greatly reducing overall work efficiency. Summary of the Invention

[0005] This invention proposes a welding trajectory optimization method and device for a spot welding robot. The method first acquires motion data of each axis of the spot welding robot, uses the motion data to determine the gun entry and exit actions, analyzes the robot's trajectory based on the coordinates of the gun entry and exit actions, and optimizes the trajectory to reduce the gun entry and exit actions during the welding process, shorten welding time, and improve welding efficiency.

[0006] A first aspect of this invention provides a method for optimizing the welding trajectory of a spot welding robot, the method comprising: Acquire motion data of the motion axes of the spot welding robot; The motion data is used to identify the welding robot’s gun entry and exit movements, and the coordinates of the welding point corresponding to the gun entry and exit movements are recorded. The coordinates of the welding point are the coordinates of the end point of the trajectory of the gun entry movement. Count multiple weld point coordinates, select at least two consecutive weld point coordinates from the multiple weld point coordinates, and calculate the first translation time of the welding gun movement based on the at least two consecutive weld point coordinates; The welding trajectory is optimized using the first translation time.

[0007] In one possible implementation of the first aspect, calculating the first translation time of the welding torch movement based on the coordinates of the at least two consecutive weld points includes: When there are two weld point coordinates, the distance the welding gun moves parallel between the two points is calculated based on the two weld point coordinates to obtain the first spatial straight-line distance; The first translation time is calculated using the first spatial straight-line distance and the preset gun advance speed.

[0008] In one possible implementation of the first aspect, the calculation of the first translation time of the welding torch movement based on the coordinates of the at least two consecutive weld points includes... When there are three or more solder joint coordinates, the distance between two adjacent solder joint coordinates is calculated to obtain several travel distances; The summation of the aforementioned travel distances yields the second spatial straight-line distance; The first translation time for welding is calculated using the second spatial linear distance and the preset gun feed speed.

[0009] In one possible implementation of the first aspect, identifying the spot welding robot's gun entry and exit movements based on the motion data includes: The motion data is used to determine the motion direction of the spot welding robot's welding gun, and the motion direction includes: the opening motion direction and the displacement motion direction; The duration when the opening movement direction and the displacement movement direction are simultaneously the same is counted to obtain the first time interval, and the duration when the welding gun of the spot welding robot moves in the displacement movement direction and the speed of the welding gun decreases is counted to obtain the second time interval. Determine the time intervals where the first time interval and the second time interval overlap, and calculate the duration of the overlapping time intervals to obtain the duration of the gun entry and exit actions; If, within the duration of the gun insertion / extraction action, the gun extension and insertion actions of the spot welding robot follow the same path but are in opposite directions, then the action of the spot welding robot within the duration of the gun insertion / extraction action is determined to be a gun insertion / extraction action.

[0010] In one possible implementation of the first aspect, the optimization of the welding trajectory using the first translation time includes: A number of second translation times are obtained, each second translation time being the time for the welding gun to move based on a different number of the weld point coordinates; Based on the number of weld point coordinates, the first translation time and several second translation times are arranged to obtain an optimization scheme, and the welding trajectory of the spot welding robot is optimized according to the optimization scheme.

[0011] A second aspect of the present invention provides a welding trajectory optimization device for a spot welding robot, the device comprising: The acquisition module is used to acquire motion data of the motion axes of the spot welding robot; The identification and recording module is used to identify the welding robot's gun-entry and gun-exit actions based on the motion data, and to record the welding point coordinates corresponding to the gun-entry and gun-exit actions. The welding point coordinates are the endpoint coordinates of the running trajectory of the gun-entry action. The calculation module is used to count multiple weld point coordinates, select at least two consecutive weld point coordinates from the multiple weld point coordinates, and calculate the first translation time of the welding gun movement based on the at least two consecutive weld point coordinates. An optimization module is used to optimize the welding trajectory using the first translation time.

[0012] In one possible implementation of the second aspect, the computing module is further configured to: When there are two weld point coordinates, the distance the welding gun moves parallel between the two points is calculated based on the two weld point coordinates to obtain the first spatial straight-line distance; The first translation time is calculated using the first spatial straight-line distance and the preset gun advance speed.

[0013] In one possible implementation of the second aspect, the computing module is further configured to: When there are three or more solder joint coordinates, the distance between two adjacent solder joint coordinates is calculated to obtain several travel distances; The summation of the aforementioned travel distances yields the second spatial straight-line distance; The first translation time for welding is calculated using the second spatial linear distance and the preset gun feed speed.

[0014] In one possible implementation of the second aspect, the identification and recording module is further configured to: The motion data is used to determine the motion direction of the spot welding robot's welding gun, and the motion direction includes: the opening motion direction and the displacement motion direction; The duration when the opening movement direction and the displacement movement direction are simultaneously the same is counted to obtain the first time interval, and the duration when the welding gun of the spot welding robot moves in the displacement movement direction and the speed of the welding gun decreases is counted to obtain the second time interval. Determine the time intervals where the first time interval and the second time interval overlap, and calculate the duration of the overlapping time intervals to obtain the duration of the gun entry and exit actions; If, within the duration of the gun insertion / extraction action, the gun extension and insertion actions of the spot welding robot follow the same path but are in opposite directions, then the action of the spot welding robot within the duration of the gun insertion / extraction action is determined to be a gun insertion / extraction action.

[0015] In one possible implementation of the second aspect, the optimization module is further configured to: A number of second translation times are obtained, each second translation time being the time for the welding gun to move based on a different number of the weld point coordinates; Based on the number of weld point coordinates, the first translation time and several second translation times are arranged to obtain an optimization scheme, and the welding trajectory of the spot welding robot is optimized according to the optimization scheme.

[0016] Compared with the prior art, the welding trajectory optimization method and device for a spot welding robot provided by the present invention has the following advantages: The present invention can first acquire the motion data of each axis of the spot welding robot, use the motion data to determine the gun entry and exit actions, analyze and optimize the robot's trajectory based on the action coordinates of the gun entry and exit actions, so as to reduce the gun entry and exit actions in the welding process, shorten the welding time, and improve the welding efficiency. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating a method for optimizing the welding trajectory of a spot welding robot according to an embodiment of the present invention. Figure 2 This is a structural schematic diagram of a spot welding robot provided in an embodiment of the present invention; Figure 3 This is an operation flowchart of a welding trajectory optimization method for a spot welding robot provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the welding trajectory optimization device for a spot welding robot provided in an embodiment of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Welding robots are industrial robots that perform welding. One common type of welding robot is the spot welding robot, which consists of a robot body, a computer control system, a teach pendant, and a spot welding system. It generally adopts the basic design of an articulated industrial robot and has six degrees of freedom: waist rotation, upper arm rotation, forearm rotation, wrist rotation, wrist swing, and wrist twisting, and is driven by hydraulic and electrical drives.

[0020] To improve the positioning accuracy of the weld point and avoid serious damage caused by high-speed collisions between the welding torch and the workpiece, the spot welding robot operates as follows after reaching the torch inlet position: the robot moves the torch at a relatively slow speed, clamps the welding clamp upon reaching the weld point, and performs the spot welding action. After completing the spot welding action, the spot welding robot typically exits the torch along the same path, thus completing the torch inlet and outlet action for a single weld point.

[0021] However, the commonly used methods have the following technical problems: Because a group of gun-entry and exit movements of a spot welding robot have the same path but opposite directions, and the speed decreases significantly during these movements, the movement efficiency is low. Furthermore, if the straight-line distance between the current weld point and the next weld point is less than the gun-entry / exit distance, two gun-entry / exit movements are often required between two welding sessions, increasing processing time. This is especially true when welding high-precision components, where the distance between weld points is short, often requiring a significant amount of time for gun-entry / exit movements, resulting in long welding times and greatly reducing overall work efficiency.

[0022] To address the aforementioned issues, the following specific embodiments will provide a detailed description and explanation of a welding trajectory optimization method for a spot welding robot provided in this application.

[0023] Reference Figure 1 The diagram shows a flowchart of a welding trajectory optimization method for a spot welding robot according to an embodiment of the present invention.

[0024] In one embodiment, the method is applicable to a spot welding robot. (See reference...) Figure 2 The diagram shows a structural schematic of a spot welding robot according to an embodiment of the present invention.

[0025] The spot welding robot consists of a robot body, a computer control system, a teach pendant, and a spot welding system. To meet the requirements of flexible movement, the welding robot typically adopts the basic design of an articulated industrial robot, generally possessing six degrees of freedom: waist rotation, upper arm rotation, forearm rotation, wrist rotation, wrist swing, and wrist twist. Its drive methods include hydraulic and electric drives.

[0026] Welding clamp: A mechanical structure that performs the action of pressing the electrode against the workpiece during spot welding; Gun advance: The action of the welding clamp entering the workpiece area in an open position and reaching the coordinates of the weld point; Gun withdrawal: The action of withdrawing the welding gun from the workpiece area in an open position after the spot welding action is completed; Gun-attacking position: The starting position of the gun-attacking action; Gun Draw Position: The position where the gun draw action ends.

[0027] Robot hand: refers to the component mounted on the robot's wrist that directly grasps the workpiece or performs tasks. In spot welding robots, it refers to the welding clamp.

[0028] The hand position of a spot welding robot: that is, the position and orientation of the welding clamp, including its spatial location and the orientation of the clamp opening. Specifically, the welding trajectory optimization method for the spot welding robot is applicable to a computer control system, which controls the spot welding robot to perform welding operations.

[0029] As an example, the welding trajectory optimization method for the spot welding robot may include: S11. Obtain motion data of the motion axes of the spot welding robot.

[0030] The motion data includes the positioning data of each axis of the spot welding robot.

[0031] Each joint of an industrial robot contains a servo motor system and a reducer responsible for power output and motion control, as well as an encoder to detect the actual rotation angle of the joint. The encoder readings are used not only for servo system feedback control (ensuring motion accuracy), but also to calculate the current opening angle of the joint through a fixed proportional conversion relationship (there are two types of encoders: absolute and incremental. Absolute encoder readings can be directly converted to obtain the angle between the two robotic arms at the joint's front and rear ends; incremental encoder output values ​​need to be converted in conjunction with the initial angle). The rotation axis of the robot joint is the motion axis, and the angle between the two links connected to the motion axis is the positioning data for each axis.

[0032] In practical implementation, the robot's motion axes are equipped with encoders, which convert the rotation angles of each axis into readable digital signals. The rotation angles of each axis can be read using OPC communication tools. Combining the robot's structural characteristics and dimensional parameters, the robot's motion model can be used to substitute the encoder angle readings into the pose model to obtain data such as the angle, direction of motion, and speed of the spot welding robot's end effector.

[0033] By acquiring the positioning data of each axis of the robot, the robot's motion trajectory can be determined, and the actions can be optimized based on the motion trajectory to shorten its movement distance and improve welding efficiency.

[0034] S12. Identify the welding robot's gun-entry and gun-exit actions based on the motion data, and record the welding point coordinates corresponding to the gun-entry and gun-exit actions. The welding point coordinates are the endpoint coordinates of the trajectory of the gun-entry action.

[0035] In one embodiment, the welding point coordinates are the endpoint coordinates of the trajectory of the gun-feeding action, specifically the coordinates of the welding clamp closing point (i.e., the contact point where the welding clamps grip the welding clamp) at the end of the gun-feeding action of the spot welding robot. Since the position from the welding clamp closing point to the welding clamp mounting and fixing point is relatively fixed, this coordinate can be used as a reference to locate the welding point.

[0036] In one embodiment, the main time-consuming aspect of welding is the repeated insertion and withdrawal of the welding torch at close welding points, which reduces processing efficiency. It is possible to first determine where the insertion and withdrawal of the welding torch occurs, then determine the coordinates of these movements, and subsequently optimize or adjust the welding trajectory based on these coordinates to shorten welding time.

[0037] When planning the welding trajectory, some welding points may be close together. The spot welding robot can move directly between the two points without repeatedly performing the gun entry and exit actions. In order to accurately determine whether the spot welding robot has performed the gun entry and exit actions, in an optional embodiment, step S12 may include the following sub-steps: S121. The motion direction of the spot welding robot is determined using the motion data, and the motion direction includes: the opening motion direction and the displacement motion direction.

[0038] In one embodiment, the opening movement direction can be the orientation of the opening of the welding clamp of the spot welding robot; the displacement movement direction can be the movement direction of the welding clamp of the spot welding robot.

[0039] In one implementation, the positioning data of each axis during the robot's operation can be continuously collected, and the positioning data of the motion axes can be substituted into the robot's kinematic model according to a unified time axis, thereby calculating the orientation of the welding clamp opening and the direction of displacement at each moment.

[0040] Specifically, by establishing the DH coordinate system of the industrial robot (Denavit and Hartenberg proposed a matrix method for establishing a coordinate system for each link in the joint chain, namely the DH parameter method), the spatial position and orientation of each link of the industrial robot can be expressed through a homogeneous coordinate transformation matrix (the welding clamp is usually mounted on the sixth axis of the robot, and the angle between the opening motion direction and the axis of the sixth axis is a fixed value, so the opening motion direction can also be obtained through the DH parameter method). The variables in the homogeneous coordinate transformation matrix are the link length (a fixed parameter of the robot) and the link angle (i.e., the positioning data of each axis). After substituting the link length and link angle readings into the kinematic equations, the current opening orientation of the welding clamp can be calculated.

[0041] S122. Calculate the duration when the opening movement direction and the displacement movement direction are simultaneously the same to obtain a first time interval, and calculate the duration when the welding gun of the spot welding robot moves in the displacement movement direction and the welding gun speed decreases to obtain a second time interval.

[0042] In one implementation, the duration of the spot welding robot's welding clamp moving in the opening motion direction can be counted first, for example, the duration is 12:34-12:56; It can also count the duration of the welding gun of the spot welding robot moving in the displacement direction, for example, the duration is 12:43-13:12.

[0043] Then the duration when the two directions are the same can be determined. For example, if the opening motion direction and the displacement motion direction are the same during the time period from 12:52 to 12:55, then 12:52 to 12:55 can be taken as the first time interval.

[0044] Continuing with the example above, the welding clamp of the spot welding robot moves in the direction of displacement for a period of 12:43-13:12. During the time interval of 12:53-13:12, the speed of the welding clamp decreases, so 12:53-13:12 can be considered as the second time interval.

[0045] S123. Determine the time intervals where the first time interval and the second time interval overlap, and calculate the duration of the overlapping time intervals to obtain the duration of the gun entry and exit actions.

[0046] Specifically, the first time interval can be determined by identifying the time interval during which the welding gun opening faces the same direction as the displacement movement. Then, the second time interval can be determined by identifying the time interval during which the welding gun's movement speed decreases. The first and second time intervals can be combined to determine the intersection area, thus obtaining the duration of the gun-entry / exit action. The time interval corresponding to the intersection area can be defined as the duration of the gun-entry / exit action. Regarding the direction of movement, the robot's posture changes can be evaluated at certain time intervals (e.g., 100 milliseconds). The change in the welding gun's spatial position can be calculated using two sets of readings (resulting in a vector containing the distance and direction of movement). This direction of movement can then be compared with the welding gun's opening orientation to determine if they are in the same direction.

[0047] Continuing with the example above, the first time interval is 12:52-12:55, the second time interval is 12:53-13:12, and the overlapping time is 12:53-12:55. Therefore, the duration of the welding robot's gun-entry / exit action can be obtained from the time the robot performs the action from 12:53-12:55.

[0048] S124. If, within the duration of the gun insertion / extraction action, the gun insertion and extraction actions of the spot welding robot follow the same path but are in opposite directions, then the action of the spot welding robot within the duration of the gun insertion / extraction action is determined to be a gun insertion / extraction action.

[0049] According to the analysis of step S12, since the position from the closing point of the welding gun to the fixed position of the welding gun is relatively fixed, the closing point of the welding gun can be used as the reference coordinate point to obtain the starting coordinate and ending coordinate of the welding gun when it performs the gun-feeding action. The path and direction vector of the gun-feeding action can be determined based on the starting coordinate and ending coordinate of the gun-feeding action. Similarly, obtain the starting and ending coordinates of the welding gun when it performs the gun extension action, and determine the path and direction vector of the gun extension action based on the starting and ending coordinates of the gun extension action.

[0050] Finally, it is determined whether the paths of the gun-advancing and gun-exiting actions are the same, and whether the direction vectors of the gun-advancing and gun-exiting actions are the same. If both are the same, then the action performed by the spot welding robot during the gun-advancing and gun-exiting action can be identified as a gun-advancing and gun-exiting action.

[0051] S13. Count the coordinates of multiple weld points, select at least two consecutive weld point coordinates from the multiple weld point coordinates, and calculate the first translation time of the welding gun movement based on the at least two consecutive weld point coordinates.

[0052] In one embodiment, the entire welding process may include multiple welding points, each with a corresponding gun entry / exit action. The coordinates of these multiple welding points can be obtained by recording the coordinates corresponding to each gun entry / exit action.

[0053] In one embodiment, the first translation time refers to the time it takes for the welding gun of the spot welding robot to move directly between the coordinates of the two welding points.

[0054] During the welding process, if the spot welding robot moves directly between the coordinates of two welding points, it is not necessary to perform the insertion and withdrawal of the welding gun at each welding point, and welding can be carried out directly.

[0055] The first translation time between two, three, four... or N consecutive weld point coordinates can be calculated, and then the welding trajectory can be optimized using this first translation time as a reference, thereby shortening the overall welding operation time.

[0056] In an optional embodiment, two consecutive solder joint coordinates may be selected from a plurality of solder joint coordinates, wherein, as an example, step S13 may include the following sub-steps: S21. When there are two welding point coordinates, calculate the distance the welding gun moves parallel between the two points based on the two welding point coordinates to obtain the first spatial straight-line distance.

[0057] Suppose there are 10 solder joint coordinates. You can choose the first and second consecutive solder joint coordinates, the second and third consecutive solder joint coordinates, or the seventh and eighth consecutive solder joint coordinates.

[0058] Then, the spatial straight-line distance between these two coordinates is calculated. This distance is the distance that the welding gun of the spot welding robot directly translates, thus obtaining the first spatial straight-line distance.

[0059] S22. The first translation time is calculated using the first spatial straight-line distance and the preset gun advance speed.

[0060] Specifically, the first spatial linear distance can be divided by a preset gun-feeding speed to obtain the first translation time. The preset gun-feeding speed can be the speed at which the spot welding robot controls the welding gun's entry and exit movements, as pre-set by the technician.

[0061] The time required for the spot welding robot to move directly from the current welding point A coordinate to the next welding point B coordinate at the welding point B coordinate by using the first spatial straight-line distance and the preset gun advance speed, without performing the gun advance and exit action, can be calculated. This time can be used as a reference for technicians to consider whether, when planning the welding trajectory, the welding gun can be moved directly from the welding point A coordinate to the welding point B coordinate, so that it is not necessary to perform a gun advance and exit action at the welding point A coordinate and then move to the welding point B coordinate to perform another gun advance and exit action.

[0062] In another alternative embodiment, three or more consecutive solder joint coordinates may be selected from a plurality of solder joint coordinates, wherein, as an example, step S13 may include the following sub-steps: S31. When there are three or more solder joint coordinates, calculate the distance between two adjacent solder joint coordinates to obtain several travel distances.

[0063] Suppose there are 10 solder joint coordinates. You can randomly select the first, second, and third consecutive solder joint coordinates; you can randomly select the second, third, fourth, and fifth consecutive solder joint coordinates; or you can randomly select the sixth, seventh, eighth, ninth, and tenth consecutive solder joint coordinates.

[0064] Then, the spatial straight-line distance between every two adjacent coordinates is calculated. This distance is the distance that the welding gun of the spot welding robot directly translates, resulting in a travel distance.

[0065] For example, by randomly selecting the coordinates of the first, second, and third consecutive solder joints, the distance between the coordinates of the first and second consecutive solder joints can be calculated to obtain the first travel distance. Then, the distance between the coordinates of the second and third consecutive solder joints can be calculated to obtain the second travel distance.

[0066] S32. Summing the several travel distances together, we obtain the second spatial straight-line distance.

[0067] Continuing with the example above, suppose we randomly select the coordinates of the first, second, and third consecutive solder joints, calculate the two travel distances, add the two travel distances together, and obtain the spatial straight-line distance between the coordinates of the three consecutive solder joints, thus obtaining the second spatial straight-line distance.

[0068] S33. Calculate the first translation time for welding using the second spatial linear distance and the preset gun feed speed.

[0069] Similarly, following step S22, the first translation time for welding can be calculated by dividing the second spatial straight-line distance by the preset gun feed speed.

[0070] In an optional embodiment, it is not necessary to consider whether the solder joints are on the same plane, nor whether there are obstacles between the solder joints that prevent the welding clamp from moving in a straight line between the two points. The direct spatial distance between each solder joint is calculated directly, and then the time required for direct translation between two solder joints is calculated: The time required for direct translation = linear distance between solder joints / gun entry speed (the spatial coordinates of the solder joints are obtained when the gun entry and exit action is completed).

[0071] It should be noted that spatial distance can be obtained using standard three-dimensional coordinate calculation methods.

[0072] The calculated data includes the time required for direct movement between two weld points. This data is then compared with the actual data collected (in actual data collection, the start time of the previous torch insertion and the end time of the next torch insertion can be confirmed to calculate the time required for the welding torch to move to the next weld point after completing the previous welding).

[0073] S14. Optimize the welding trajectory using the first translation time.

[0074] After calculating the first translation time, technicians can use the first translation time as a reference to determine whether to directly control the translation of the welding torch between the two weld points, thereby reducing the torch entry and exit movements, shortening the welding processing time, and improving processing efficiency.

[0075] It should be noted that, considering the application scenario is an automated production line, and the target is to automatically analyze the status of a large number of robots, there may be unknown and special working states during the extensive analysis. In such states, although all the conditions for entering or exiting the gun are met, the actual action may not be entering or exiting the gun. In this case, the action judgment algorithm can be modified. Here, machine learning is used to train an artificial intelligence judgment model to handle the massive number of devices in an industrial setting.

[0076] After accurately identifying the robot's movements in and out of the welding gun, the robot's trajectory is analyzed based on indicators such as the number of times it enters and exits the gun and the spacing between welding points, and an optimization plan is generated.

[0077] Specifically, the optimization scheme can include at least two parts: ① generating the robot's actual welding trajectory based on the above data; ② generating one or more theoretically optimal trajectories for the robot based on the above data. Welding can be performed according to the optimal trajectory or the trajectory with the least time consumption, thereby reducing the gun entry and exit movements, shortening the welding processing time, and improving processing efficiency.

[0078] In an optional embodiment, step S14 may include the following sub-steps: S141. Obtain several second translation times, each of which is the time for the welding gun to move based on a different number of the coordinates of the welding points.

[0079] In one embodiment, the first translation time is determined by selecting at least two consecutive weld point coordinates from a plurality of weld point coordinates, and then calculating the first translation time for the welding torch movement based on these at least two consecutive weld point coordinates. Specifically, this refers to the translation time under one specific condition.

[0080] To make a more intuitive comparison, multiple second translation times can be obtained. Each second translation time is the translation time calculated by selecting different or the same number of consecutive weld point coordinates in the same welding trajectory scheme.

[0081] Using the example above, suppose there are 10 solder joint coordinates. We can randomly select the first, second, and third consecutive solder joint coordinates to calculate the first translation time.

[0082] Next, the second translation time can be calculated by randomly selecting the coordinates of the first and second consecutive solder points; the second translation time can be calculated by randomly selecting the coordinates of the fourth and fifth consecutive solder points; the second translation time can be calculated by randomly selecting the coordinates of the second, third, fourth, and fifth consecutive solder points; the second translation time can be calculated by randomly selecting the coordinates of the sixth, seventh, eighth, ninth, and tenth consecutive solder points; and so on. This way, multiple second translation times for the welding torch movement can be calculated by obtaining the coordinates of solder points with different or the same number of solder points.

[0083] S142. Arrange the first translation time and several second translation times according to the number of weld point coordinates to obtain an optimization scheme, and optimize the welding trajectory of the spot welding robot according to the optimization scheme.

[0084] Finally, the first translation time and several second translation times can be arranged according to the number of solder joint coordinates to form an optimization scheme for optimization reference.

[0085] Continuing with the example above, suppose there are 10 solder joint coordinates. We can randomly select the first, second, and third consecutive solder joint coordinates to calculate the first translation time. Then, the multiple second translation times include several second translation times for two solder joint coordinates, several second translation times for three solder joint coordinates, and so on, several second translation times for eight solder joint coordinates.

[0086] Then, we can first arrange several second translation times about the coordinates of two solder joints; classify the first translation time into the second translation time about the coordinates of three solder joints, and then arrange the first translation time and several second translation times about the coordinates of three solder joints; then several second translation times about the coordinates of four solder joints... and so on.

[0087] Finally, the optimization plan can be sent to the technical staff so that they can refer to which translation times are practical. This will allow the welding gun to avoid moving in and out of the welding gun at the weld point coordinates corresponding to that translation time, thereby improving efficiency.

[0088] In addition, the optimization scheme can include reducing the welding time of the gun entry and exit action and multiple welding times that include the gun entry and exit action. The two can be compared to calculate the time it takes for the gun to move directly to the position between two welding points without exiting, relative to the current actual running trajectory, and the time consumption of the two motion schemes.

[0089] Alternatively, the optimization plan can be sent to the process management personnel, who can then use this original optimization plan to identify the solder joints with the greatest potential for performance improvement and, based on the actual conditions between the solder joints, determine whether there are any better trajectory plans.

[0090] A comprehensive analysis of various trajectory schemes during the spot welding process is conducted, such as the motion scheme of exiting and then re-entering the welding torch between consecutive welding points, and the motion scheme of directly positioning the next welding point, to analyze the time efficiency of each scheme.

[0091] In one implementation, the metric for determining the optimal path is the path time.

[0092] The optimized program is analyzed and evaluated to verify the optimization results. The verification process involves the robotics engineer modifying the program based on the report's findings after the optimization plan is implemented, and then running the program again.

[0093] The verification step is essentially a second use of this method. The verification step is set up here to increase the usability of this method in actual work.

[0094] After verification is completed, the welding time of the verification can be used to generate a final analysis summary report for technical personnel or reference.

[0095] Reference Figure 3 The diagram shows an operation flowchart of a welding trajectory optimization method for a spot welding robot according to an embodiment of the present invention.

[0096] First, read the axis displacement data of the industrial robot in operation.

[0097] Second, the encoders on each axis read the records.

[0098] Third, the recognition of gun movement characteristics.

[0099] Fourth, analyze the trajectory by combining the characteristics of the movements.

[0100] Fifth, output an optimization suggestion report regarding the number of times the gun enters and exits.

[0101] Sixth, optimize the robot's motion program (which can be done manually).

[0102] Seventh, if the optimization fails to meet the requirements of the test run, return to continue optimizing the program.

[0103] Eighth, if the optimization meets the requirements of the operational tests, then conduct a summary analysis.

[0104] Ninth, generate a summary report.

[0105] Specifically, in practical applications, its operation may also include the following steps: The first step is to calculate the pose of the welding clamp (i.e., the hand) (which may include the robot hand). The second step is to obtain the encoder readings of each motion axis using common robot axis encoder data reading methods in the industrial control field (such as using communication methods based on the OPCUA standard, or using the PC SDK to perform secondary development on the robot controller and then directly reading the robot position information through the PC Interface), and record them based on a unified time axis.

[0106] The third step is to substitute the motion axis encoder data into the robot pose equation to calculate the opening orientation of the welding clamp at the end (it should be noted that because the welding clamp itself has an opening orientation with a fixed angle relative to the mounting base, the opening orientation of the welding clamp can be calculated based on this fixed angle and the posture of the robot end in the world coordinate system).

[0107] Step 4: Since the rotation angle of each shaft joint can be obtained by reading the encoder, and the linkage distance between the shaft joints is fixed and known (the linkage distance is determined when the equipment is shipped from the factory), the opening orientation and deflection angle of the welding clamp can be calculated using these parameters. Step 5: Substitute the motion axis encoder data into the robot's kinematic equations to calculate the motion direction and speed of the robot's end effector welding clamp at each moment; Step 6: Determine whether the spot welding robot performs the gun-entry / exit action. If it does, the spot welding robot exhibits the following characteristics when performing the gun-entry / exit action: The direction of the welding clamp's movement is the same as (or opposite to) the direction of the opening's movement; The welding clamp moves at a slower speed than normal. Step 7: After confirming the characteristics of the gun entry and exit actions in step 6, machine learning methods can be used to build and train an algorithm model.

[0108] Step 8: Based on the identified gun entry and exit actions, record the coordinates of the solder joint (the endpoint of the gun entry action).

[0109] Step 9: Statistically record all gun-entry and gun-exit movements during the spot welding robot's operation, and record the travel distance of each gun-entry and gun-exit movement.

[0110] Step 10: Calculate the straight-line distance between all consecutive solder joints.

[0111] Step 11: Conduct a comprehensive analysis of various trajectory schemes during the spot welding process, such as the motion scheme of exiting and then re-entering the welding torch between consecutive welding points, and the motion scheme of directly positioning the next welding point, and analyze the time efficiency of each scheme.

[0112] Step 12: Generate optimization solutions. List the alternative solutions with significant (the degree can be defined by the customer) time advantages calculated in Step 9 to provide optimization suggestions to the engineers.

[0113] Step 13: Analyze and evaluate the optimized program to verify the optimization results.

[0114] Step 14: Generate the final analysis summary report.

[0115] It should be noted that in actual production, robot trajectories are usually taught manually, so the actual path of the robot entering and exiting the welding torch may have a certain angle with the direction of the opening movement (rather than being completely collinear). Furthermore, the operating speed of the spot welding robot when performing the entry and exit torch movements may not have a fixed decrease. Therefore, in the early stages of algorithm model training, manual data annotation is necessary. After accumulating a certain amount of actual production sample data, the algorithm model gradually matures, eventually achieving fully automatic and accurate recognition of the spot welding robot's entry and exit torch movements.

[0116] Typically, when a robot performs two welding tasks, if the two weld points are on the same plane and there are no obstacles in between, it can directly move to the second weld point after welding the first one. Compared to the previous method of exiting the welding torch after welding and then re-entering it, the former is more efficient (mainly in terms of time). The former requires two torch entry / exit operations, while the latter only requires one. For the same two weld points, the average number of torch entry / exit operations per weld point (number of torch entry / exit operations per weld point = number of torch entry / exit operations / total number of weld points) is 1 for the former and 0.5 for the latter.

[0117] In actual production, factors such as the distance between two welding points, whether they are on the same plane, and whether there are obstacles in between need to be considered comprehensively. The value of this patent lies in proposing an automatic method for identifying the action of the welding gun entering and exiting. Since the data required for the determination comes from reading from the equipment, this invention can be widely applied, achieving an analytical efficiency that cannot be matched by manually shooting and analyzing videos.

[0118] By analyzing individual machines and extending the analysis to workstations, production lines, and workshops, the overall welding robot's entry and exit from the welding gun can be evaluated. Based on this, production managers can focus on the operation of machines with a high number of entry and exit times at each welding point.

[0119] This invention can be applied to the efficiency diagnosis and analysis of automated production line equipment, and is used to perform efficiency analysis on spot welding robots with complex movements; moreover, this invention is based on the readings of the robot motion axis positioning encoder for analysis, which is more accurate and intuitive than the robot motion trajectory recognition obtained by integrating the speed sensor; In addition, the present invention uses machine learning methods for identification, which has an analysis efficiency that is incomparable to manual analysis when faced with a large number of different motion trajectories of industrial robots.

[0120] In this embodiment, the present invention can first acquire motion data of each axis of the spot welding robot, use the motion data to determine the gun entry and exit actions, analyze the robot's trajectory based on the action coordinates of the gun entry and exit actions to obtain an optimization scheme, and use the optimization scheme to optimize welding, so as to reduce the gun entry and exit actions in the welding process, shorten welding time, and improve welding efficiency.

[0121] This invention also provides a welding trajectory optimization device for a spot welding robot, see [link to relevant documentation]. Figure 4 The diagram shows a schematic of the structure of a welding trajectory optimization device for a spot welding robot according to an embodiment of the present invention.

[0122] As an example, the welding trajectory optimization device for the spot welding robot may include: The acquisition module 401 is used to acquire motion data of the motion axes of the spot welding robot; The identification and recording module 402 is used to identify the in-and-out motion of the spot welding robot based on the motion data, and to record the coordinates of the welding point corresponding to the in-and-out motion, wherein the coordinates of the welding point are the coordinates of the end point of the trajectory of the in-and-out motion. The calculation module 403 is used to count multiple weld point coordinates, select at least two consecutive weld point coordinates from the multiple weld point coordinates, and calculate the first translation time of the welding gun movement based on the at least two consecutive weld point coordinates. The optimization module 404 is used to optimize the welding trajectory using the first translation time.

[0123] Optionally, the computing module is further configured to: When there are two weld point coordinates, the distance the welding gun moves parallel between the two points is calculated based on the two weld point coordinates to obtain the first spatial straight-line distance; The first translation time is calculated using the first spatial straight-line distance and the preset gun advance speed.

[0124] Optionally, the computing module is further configured to: When there are three or more solder joint coordinates, the distance between two adjacent solder joint coordinates is calculated to obtain several travel distances; The summation of the aforementioned travel distances yields the second spatial straight-line distance; The first translation time for welding is calculated using the second spatial linear distance and the preset gun feed speed.

[0125] Optionally, the identification and recording module is further used for: The motion data is used to determine the motion direction of the spot welding robot's welding gun, and the motion direction includes: the opening motion direction and the displacement motion direction; The duration when the opening movement direction and the displacement movement direction are simultaneously the same is counted to obtain the first time interval, and the duration when the welding gun of the spot welding robot moves in the displacement movement direction and the speed of the welding gun decreases is counted to obtain the second time interval. Determine the time intervals where the first time interval and the second time interval overlap, and calculate the duration of the overlapping time intervals to obtain the duration of the gun entry and exit actions; If, within the duration of the gun insertion / extraction action, the gun extension and insertion actions of the spot welding robot follow the same path but are in opposite directions, then the action of the spot welding robot within the duration of the gun insertion / extraction action is determined to be a gun insertion / extraction action.

[0126] Optionally, the optimization module is further configured to: A number of second translation times are obtained, each second translation time being the time for the welding gun to move based on a different number of the weld point coordinates; Based on the number of weld point coordinates, the first translation time and several second translation times are arranged to obtain an optimization scheme, and the welding trajectory of the spot welding robot is optimized according to the optimization scheme.

[0127] Those skilled in the art will understand that, for ease of description and brevity, the specific working process of the device described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0128] Furthermore, this application also provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the welding trajectory optimization method for the spot welding robot as described in the above embodiments.

[0129] Furthermore, embodiments of this application also provide a computer-readable storage medium storing computer-executable instructions for causing a computer to execute the welding trajectory optimization method for a spot welding robot as described in the above embodiments.

[0130] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for optimizing the welding trajectory of a spot welding robot, characterized in that, The method includes: Acquire motion data of the motion axes of the spot welding robot, the motion data including the axis positioning data of the spot welding robot; The motion data is used to identify the welding robot’s gun entry and exit movements, and the coordinates of the welding point corresponding to the gun entry and exit movements are recorded. The coordinates of the welding point are the coordinates of the end point of the trajectory of the gun entry movement. Count multiple weld point coordinates, select at least two consecutive weld point coordinates from the multiple weld point coordinates, and calculate the first translation time of the welding gun movement based on the at least two consecutive weld point coordinates; The welding trajectory is optimized using the first translation time.

2. The welding trajectory optimization method for a spot welding robot according to claim 1, characterized in that, The calculation of the first translation time of the welding torch movement based on the coordinates of the at least two consecutive weld points includes: When there are two weld point coordinates, the distance the welding gun moves parallel between the two points is calculated based on the two weld point coordinates to obtain the first spatial straight-line distance; The first translation time is calculated using the first spatial straight-line distance and the preset gun advance speed.

3. The welding trajectory optimization method for a spot welding robot according to claim 1, characterized in that, The calculation of the first translation time of the welding torch movement based on the coordinates of the at least two consecutive weld points includes... When there are three or more solder joint coordinates, the distance between two adjacent solder joint coordinates is calculated to obtain several travel distances; The summation of the aforementioned travel distances yields the second spatial straight-line distance; The first translation time is calculated using the second spatial straight-line distance and the preset gun advance speed.

4. The welding trajectory optimization method for a spot welding robot according to claim 1, characterized in that, The step of identifying the spot welding robot's gun entry and exit movements based on the motion data includes: The motion data is used to determine the motion direction of the spot welding robot's welding gun, and the motion direction includes: the opening motion direction and the displacement motion direction; The duration when the opening movement direction and the displacement movement direction are simultaneously the same is counted to obtain the first time interval, and the duration when the welding gun of the spot welding robot moves in the displacement movement direction and the speed of the welding gun decreases is counted to obtain the second time interval. Determine the time intervals where the first time interval and the second time interval overlap, and calculate the duration of the overlapping time intervals to obtain the duration of the gun entry and exit actions; If, within the duration of the gun insertion / extraction action, the gun extension and insertion actions of the spot welding robot follow the same path but are in opposite directions, then the action of the spot welding robot within the duration of the gun insertion / extraction action is determined to be a gun insertion / extraction action.

5. The method for optimizing the welding trajectory of a spot welding robot according to claim 1, characterized in that, The optimization of the welding trajectory using the first translation time includes: A number of second translation times are obtained, each second translation time being the time for the welding gun to move based on a different number of the weld point coordinates; Based on the number of weld point coordinates, the first translation time and several second translation times are arranged to obtain an optimization scheme, and the welding trajectory of the spot welding robot is optimized according to the optimization scheme.

6. A welding trajectory optimization device for a spot welding robot, characterized in that, The device includes: The acquisition module is used to acquire motion data of the motion axes of the spot welding robot, the motion data including the axis positioning data of the spot welding robot; The identification and recording module is used to identify the welding robot's gun-entry and gun-exit actions based on the motion data, and to record the welding point coordinates corresponding to the gun-entry and gun-exit actions. The welding point coordinates are the endpoint coordinates of the running trajectory of the gun-entry action. The calculation module is used to count multiple weld point coordinates, select at least two consecutive weld point coordinates from the multiple weld point coordinates, and calculate the first translation time of the welding gun movement based on the at least two consecutive weld point coordinates. An optimization module is used to optimize the welding trajectory using the first translation time.

7. The welding trajectory optimization device for a spot welding robot according to claim 6, characterized in that, The computing module is also used for: When there are two weld point coordinates, the distance the welding gun moves parallel between the two points is calculated based on the two weld point coordinates to obtain the first spatial straight-line distance; The first translation time is calculated using the first spatial straight-line distance and the preset gun advance speed.

8. The welding trajectory optimization device for a spot welding robot according to claim 6, characterized in that, The computing module is also used for: When there are three or more solder joint coordinates, the distance between two adjacent solder joint coordinates is calculated to obtain several travel distances; The summation of the aforementioned travel distances yields the second spatial straight-line distance; The first translation time for welding is calculated using the second spatial linear distance and the preset gun feed speed.

9. The welding trajectory optimization device for a spot welding robot according to claim 6, characterized in that, The identification and recording module is also used for: The motion data is used to determine the motion direction of the spot welding robot's welding gun, and the motion direction includes: the opening motion direction and the displacement motion direction; The duration when the opening movement direction and the displacement movement direction are simultaneously the same is counted to obtain the first time interval, and the duration when the welding gun of the spot welding robot moves in the displacement movement direction and the speed of the welding gun decreases is counted to obtain the second time interval. Determine the time intervals where the first time interval and the second time interval overlap, and calculate the duration of the overlapping time intervals to obtain the duration of the gun entry and exit actions; If, within the duration of the gun insertion / extraction action, the gun extension and insertion actions of the spot welding robot follow the same path but are in opposite directions, then the action of the spot welding robot within the duration of the gun insertion / extraction action is determined to be a gun insertion / extraction action.

10. The welding trajectory optimization device for a spot welding robot according to claim 6, characterized in that, The optimization module is also used for: A number of second translation times are obtained, each second translation time being the time for the welding gun to move based on a different number of the weld point coordinates; Based on the number of weld point coordinates, the first translation time and several second translation times are arranged to obtain an optimization scheme, and the welding trajectory of the spot welding robot is optimized according to the optimization scheme.

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