Method of controlling a weaving robot to weave and weaving robot system

Abstract

The embodiment of the present disclosure relates to the technical field of welding, and provides a method for controlling swing welding motion of a swing welding robot and a swing welding robot system, the method for controlling swing welding motion of the swing welding robot comprising: presetting a welding path located on a workpiece to be welded and parameters of a welding torch relative to the welding path, the extension direction of the welding path being a first direction, and the direction parallel to the surface of the workpiece to be welded and perpendicular to the welding path being a second direction; obtaining a swing welding path according to the welding path and the parameters of the welding torch relative to the welding path, both sides of the welding path having the swing welding path, and the swing welding path comprising a plurality of continuous welding points; the mechanical arm structure of the swing welding robot controls a wrist joint to move along the first direction, the wrist joint controls the end of the welding torch to move along the second direction, and the mechanical arm structure and the wrist joint jointly control the end of the welding torch to move, so that the swing welding robot welds along the swing welding path on the surface of the workpiece to be welded. At least the welding efficiency of the swing welding robot can be improved.

Description

Technical Field

[0001] This disclosure relates to the field of welding technology, and in particular to a method for controlling the oscillating welding motion of an oscillating welding robot and an oscillating welding robot system. Background Technology

[0002] With the rapid development of the manufacturing industry, robot systems have been widely used in the field of automated manufacturing. For welding robots, oscillating welding refers to the robot controlling the welding torch to periodically oscillate left and right at a specific angle along the welding path to perform welding, thereby widening the weld and increasing the welding strength.

[0003] Currently, when performing oscillating welding motions, the robot's arm also needs to swing to achieve the oscillating welding action. In many welding applications, the welding torch of the oscillating welding robot often needs to oscillate at high frequencies. However, the robot's arm has a large mass, and the robot's oscillation inertia is also large. This prevents the robot from achieving a high oscillation frequency during the oscillation welding motion, thus affecting the welding efficiency of the oscillating welding robot. Summary of the Invention

[0004] This disclosure provides a method for controlling the oscillating motion of a oscillating welding robot and a oscillating welding robot system, which at least helps to improve the welding efficiency of the oscillating welding robot.

[0005] According to some embodiments of this disclosure, one aspect of this disclosure provides a method for controlling the oscillating welding motion of an oscillating welding robot, comprising: presetting a welding path located on the workpiece to be welded, and parameters of the welding torch relative to the welding path, wherein the extension direction of the welding path is a first direction, and a direction parallel to the surface of the workpiece to be welded and perpendicular to the welding path is a second direction; obtaining an oscillating welding path based on the welding path and the parameters of the welding torch relative to the welding path, wherein the oscillating welding path is present on both sides of the welding path, and the oscillating welding path includes multiple continuous welding points; the robotic arm structure of the oscillating welding robot controls the wrist joint to move along the first direction, the wrist joint controls the end of the welding torch to move along the second direction, and the robotic arm structure and the wrist joint jointly control the movement of the end of the welding torch, so that the oscillating welding robot welds along the oscillating welding path on the surface of the workpiece to be welded.

[0006] In some embodiments, the wrist joint moves along a wrist joint path, the wrist joint path extends along the first direction, and the robotic arm structure of the oscillating welding robot controls the wrist joint to move along the first direction by: obtaining the next welding point in the oscillating welding path, obtaining the next position of the wrist joint according to the position of the next welding point, the next position of the wrist joint being located at the projection position of the next welding point on the wrist joint path.

[0007] In some embodiments, controlling the movement of the welding torch tip along the second direction by the wrist joint includes: obtaining the position of the welding torch tip corresponding to the next welding point based on the position of the next welding point; obtaining a position vector based on the position of the welding torch tip corresponding to the next welding point and the next position of the wrist joint; performing inverse kinematics calculation based on the position vector to obtain the wrist joint angle corresponding to the next welding point; and controlling the wrist joint to rotate to adjust to the wrist joint angle corresponding to the next welding point, thereby controlling the movement of the welding torch tip along the second direction.

[0008] In some embodiments, obtaining the position of the welding torch tip corresponding to the next welding point based on the position of the next welding point includes: ensuring that the next position of the wrist joint, the position of the welding torch tip corresponding to the next welding point, and the next welding point are on the same straight line; and obtaining the position of the welding torch tip corresponding to the next welding point based on geometric relationships through the position of the next welding point and the next position of the wrist joint.

[0009] In some embodiments, the inverse kinematics solution based on the position vector to obtain the wrist joint angle corresponding to the next welding point includes: establishing a three-dimensional rectangular coordinate system with the wrist joint as the origin, wherein the X-axis of the three-dimensional rectangular coordinate system is parallel to the welding path, and the angles between the welding torch connected to the wrist joint and the three axes of the three-dimensional rectangular coordinate system are angle one, angle two, and angle three, respectively, wherein the angle between the welding torch and the X-axis is angle one; obtaining the distance between the wrist joint and the tooling to be welded as a first distance; fixing angle one unchanged, and obtaining angle two and angle three of the wrist joint corresponding to the next welding point based on the position vector and the first distance.

[0010] In some embodiments, the parameters of the welding torch relative to the welding path include at least: the maximum distance between the welding point and the welding path on both sides of the welding path, the frequency of the oscillating welding motion, and acceptable tolerances.

[0011] In some embodiments, the welding path is a straight line.

[0012] In some embodiments, the sway welding path is a sine curve.

[0013] According to some embodiments of this disclosure, another aspect of this disclosure also provides a oscillating welding robot system, including: a base; a robotic arm structure, one end of which is connected to the base, and the other end of which has a wrist joint; a welding torch connected to the wrist joint; and a controller for controlling the wrist joint to rotate so that the welding torch oscillates, and the controller is also used to control the robotic arm structure to move, wherein the direction of movement of the robotic arm structure is different from the direction of oscillation of the welding torch.

[0014] In some embodiments, the robotic arm structure includes: a large arm, one end of which is connected to the base; a small arm, one end of which has the wrist joint; and a drive housing, which connects the small arm and the large arm.

[0015] The technical solutions provided in this disclosure have at least the following advantages:

[0016] The method for controlling the oscillating welding motion of a oscillating welding robot provided in this embodiment first presets a welding path located on the workpiece to be welded, and parameters of the welding torch relative to the welding path. The extension direction of the welding path is a first direction, and the direction parallel to the surface of the workpiece to be welded and perpendicular to the welding path is a second direction. The welding path is obtained based on the welding path and the parameters of the welding torch relative to the welding path. Oscillating welding paths exist on both sides of the welding path, and each oscillating welding path includes multiple welding points. The robotic arm structure of the oscillating welding robot controls the wrist joint to move along the first direction, and the wrist joint controls the welding torch to move along the second direction. The robotic arm structure and the wrist joint jointly control the movement of the welding torch end, so that the welding robot welds along the oscillating welding path. In related technologies, the robotic arm structure of the oscillating welding robot controls the welding torch to move along the first and second directions, while the wrist joint generally maintains a certain angle. That is, the robotic arm structure of the oscillating welding robot controls the welding torch to move along the oscillating welding path. However, in the second direction, the oscillating welding robot generally needs to have a high frequency during the oscillating welding motion. In other words, the movement of the oscillating welding robot in the second direction needs to involve multiple back-and-forth movements in a short period of time. If the robotic arm controlling the movement of the welding robot in the second direction has a large mass and inertia, the time required for the welding robot to turn back in the second direction will increase accordingly. This will reduce the frequency of the welding robot's movements and thus lower its welding efficiency. However, in this application, the welding torch tip of the welding robot moves in the second direction only through the rotation of the wrist joint. The movement of the welding torch in the second direction does not require the use of a robotic arm. Therefore, in this application, the wrist joint controlling the welding torch tip can perform multiple turns back in the second direction in a short time, thereby improving the welding efficiency of the welding robot. Attached Figure Description

[0017] One or more embodiments are illustrated by way of example with corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this disclosure or the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the path of the oscillating welding robot provided in an embodiment of the present disclosure;

[0019] Figure 2 This is a schematic diagram of another path of the oscillating welding robot provided in one embodiment of the present disclosure;

[0020] Figure 3 This is a schematic diagram of the structure of a sway welding robot performing sway welding motion according to an embodiment of the present disclosure;

[0021] Figure 4 This is another schematic diagram of the motion path of the oscillating welding robot provided in an embodiment of the present disclosure;

[0022] Figure 5 This is a schematic diagram of the geometric relationship of the oscillating welding motion of a oscillating welding robot provided in an embodiment of this disclosure;

[0023] Figure 6 This is a schematic diagram of the structure of a welding robot system provided in one embodiment of the present disclosure. Detailed Implementation

[0024] As can be seen from the background technology, current methods for controlling the motion of a tumbling welding robot suffer from low welding efficiency.

[0025] This disclosure provides a method for controlling the oscillating welding motion of a oscillating welding robot. First, a welding path is preset on the workpiece to be welded, along with parameters for the welding torch relative to the welding path. The extension direction of the welding path is a first direction, and the direction parallel to the surface of the workpiece and perpendicular to the welding path is a second direction. An oscillating welding path is obtained based on the aforementioned welding path and parameters, with oscillating welding paths on both sides. The robotic arm structure controls the wrist joint to move along the first direction, and the wrist joint controls the end of the welding torch to move along the second direction. The robotic arm and the welding torch jointly control the end of the welding torch to move along the oscillating welding path. Since this disclosure embodiment does not require the robotic arm structure to swing in the second direction to drive the movement of the welding torch end in the second direction, the movement of the welding torch end in the second direction is achieved by the wrist joint. This avoids the influence of the large-mass robotic arm structure on the oscillating welding motion frequency. Controlling the movement of the welding torch end in the second direction by wrist joint rotation can effectively increase the frequency of the oscillating welding robot's motion cycle in the second direction, meaning that the welding torch end can make multiple back-and-forth movements in the second direction within a short time, thereby effectively improving the welding efficiency of the oscillating welding robot.

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the various embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been presented in the various embodiments of the present disclosure to enable the reader to better understand the present disclosure. However, the technical solutions claimed in the present disclosure can be implemented even without these technical details and various changes and modifications based on the following embodiments.

[0027] Figure 1 This is a schematic diagram of the motion path of a welding robot according to an embodiment of this disclosure. Figure 2 This is a schematic diagram of another path of the oscillating welding robot provided in one embodiment of the present disclosure.

[0028] refer to Figures 1 to 2 The welding path 10 is preset on the tooling to be welded, and the welding torch 110 (for reference) is also preset. Figure 3 Relative to the parameters of welding path 10, the extension direction of welding path 10 is the first direction A, and the direction parallel to the surface of the tooling to be welded and perpendicular to welding path 10 is the second direction B.

[0029] Welding path 10 is preset into the controller of the oscillating welding robot. The controller can process the information preset by the user and control the oscillating welding robot to complete the oscillating welding motion.

[0030] In some embodiments, the welding path 10 can be preset along the weld seam on the surface of the workpiece to be welded. In this way, after the oscillating welding robot performs oscillating welding motion according to the preset welding path 10, it can complete the welding of the weld seam on the surface of the workpiece to be welded.

[0031] In some embodiments, the welding path 10 can be a straight line. In actual production, when two parts are welded together by a welding process, the weld seam between the two parts can generally be a straight line. If the welding path 10 is a straight line, when the oscillating welding robot performs oscillating welding on such a welding path 10, the path traversed by the welding point can periodically cross the welding path 10 so that the weld seam on the surface of the tooling to be welded can be welded together.

[0032] In some embodiments, welding torch 110 (reference) Figure 3 The parameters relative to the welding path 10 may include at least the maximum distance between the welding points on both sides of the welding path 10 and the welding path 10, the frequency of the oscillating welding motion, and acceptable tolerances. These parameters, including the maximum distance between the welding points on both sides of the welding path 10 and the welding path 10, the frequency of the oscillating welding motion, and acceptable tolerances, are input by the user into the controller of the oscillating welding robot. The user can select appropriate parameters for the welding gun 110 relative to the welding path 10 according to actual welding requirements. After receiving these parameters, the controller can process the data to perform subsequent steps for controlling the movement of the oscillating welding robot.

[0033] It is understandable that the maximum distance between the welding point and the welding path 10 on both sides is the amplitude of the oscillating welding robot's oscillation welding. The larger the maximum distance between the welding point and the welding path 10, the wider the final oscillation welding path and the stronger the oscillation weld. The smaller the maximum distance between the welding point and the welding path 10, the narrower the final oscillation welding path 10, the weaker the oscillation weld, but the shorter the total length of the oscillation welding path 10, thus improving the oscillation welding efficiency. The oscillation frequency directly reflects the oscillation welding robot's efficiency. The higher the oscillation welding frequency, the higher the efficiency and the faster the oscillation welding; the lower the oscillation welding frequency, the lower the efficiency and the slower the oscillation welding.

[0034] Figure 5 This is a schematic diagram of the geometric relationship of the oscillating welding motion of a oscillating welding robot provided in an embodiment of this disclosure.

[0035] refer to Figure 5During the oscillating welding process of the oscillating welding robot, the welding torch 110 is not always perpendicular to the surface of the workpiece to be welded. There can be a certain distance between the projection of the end of the welding torch 110 on the surface of the workpiece to be welded and the desired welding point 20. The acceptable tolerance can be regarded as the distance between the projection of the end of the welding torch 110 on the surface of the workpiece to be welded and the desired welding point 20. The smaller the acceptable tolerance, the closer the distance between the welding torch 110 of the oscillating welding robot and the workpiece to be welded during the oscillating welding process, the better the welding effect, and correspondingly, the smaller the swing amplitude of the welding torch 110, the higher the welding efficiency. The larger the acceptable tolerance, the greater the distance between the welding torch 110 of the oscillating welding robot and the workpiece to be welded during the oscillating welding process, the larger the welding range, and correspondingly, the larger the swing amplitude of the welding torch 110, the greater the fault tolerance of the oscillating welding point position. The acceptable tolerance of the oscillating welding robot is directly related to the maximum distance from the end of the welding torch 110 to the surface of the workpiece to be welded. It can be understood that the smaller the maximum distance from the end of the welding torch 110 to the surface of the workpiece to be welded, the higher the welding accuracy. When setting the acceptable tolerance, users also need to consider the maximum distance from the end of the welding torch 110 to the surface of the workpiece to be welded, so that the maximum distance from the end of the welding torch 110 to the surface of the workpiece to be welded is kept within a certain limit in order to achieve accurate and complete welding operations.

[0036] Continue to refer to Figures 1 to 2 According to welding path 10 and welding torch 110 (reference) Figure 3 The parameters of the welding path 10 are used to obtain the oscillating welding path 30. Both sides of the welding path 10 have oscillating welding paths 30, and the oscillating welding path 30 includes multiple continuous welding points.

[0037] The oscillating welding path 10 is the actual path of the welding points left on the surface of the workpiece to be welded when the oscillating welding robot performs its oscillating welding motion. Based on the welding path 10 preset by the user in the controller above and the parameters of the welding torch 110 relative to the welding path 10 set by the user, the controller can obtain the oscillating welding path 30. (Reference) Figure 1 In some embodiments, the oscillating solder path 30 can be a sinusoidal curve. The oscillating solder path 30 can also be a quasi-sinusoidal curve. That is, the oscillating solder path 30 can include multiple continuous periodic curves located on both sides of the soldering path 10. (See reference...) Figure 2 In other embodiments, the oscillating welding path 30 can also be a straight line. That is, the oscillating welding path 30 can form multiple periodically arranged triangles on both sides of the welding path 10 with the welding path 10.

[0038] Figure 3 This is a schematic diagram of the structure of a welding robot performing a welding motion according to an embodiment of the present disclosure.

[0039] refer to Figure 3The robotic arm structure 120 of the oscillating welding robot controls the wrist joint 130 to move along the first direction A, and the wrist joint 130 controls the end of the welding torch 110 to move along the second direction B. The robotic arm structure 120 and the wrist joint 130 jointly control the end of the welding torch 110 to move, so that the oscillating welding robot welds on the surface of the workpiece to be welded along the oscillating welding path 30.

[0040] In other words, the oscillating welding motion of the oscillating welding robot can be divided into two parts: one part is the movement along the first direction A controlled by the robotic arm structure 120, and the other part is the movement along the second direction B controlled by the wrist joint 130. The robotic arm structure 120 and the wrist joint 130 jointly control the oscillating welding robot to weld along the oscillating welding path 30 on the surface of the workpiece to be welded.

[0041] Figure 4 This is another schematic diagram of the motion path of the oscillating welding robot provided in an embodiment of the present disclosure, wherein the axis of the sine curve represents the wrist joint path 40.

[0042] refer to Figure 4 In some embodiments, the wrist joint 130 moves along a wrist joint path 40, which extends along a first direction A. Controlling the wrist joint 130 to move along the first direction A by the robotic arm structure 120 of the oscillating welding robot may include: obtaining the next welding point 31 in the oscillating welding path 30; obtaining the next position 41 of the wrist joint based on the position of the next welding point 31; and the next position 41 of the wrist joint being located at the projection position of the next welding point 31 on the wrist joint path 40. The wrist joint path 40 extends along the first direction A, meaning it is parallel to the welding path 10. If the welding path 10 is a straight path, then the wrist joint path 40 is also a straight path, and the robotic arm structure 120 of the oscillating welding robot controls the wrist joint 130 to move along a straight line. It is understandable that the position of the next welding point 31 corresponds to the position of the end of the next welding torch. The relative orientation between the position of the next welding point 31 and the wrist joint 130 is the same as the relative orientation between the position of the previous welding point and the wrist joint 130. That is, the relative orientation between the position of the end of the next welding torch 110 and the wrist joint 130 is the same as the relative orientation between the position of the end of the previous welding torch 110 and the wrist joint 130. Therefore, during the entire oscillating welding motion, the relative orientation between the position of the end of the welding torch 110 and the wrist joint 130 remains unchanged. The swing direction of the wrist joint 130 is only in the second direction B, and the movement direction of the wrist joint 130 is only in the first direction A. This avoids the impact of the robotic arm structure 120 swinging in the second direction B on the welding efficiency of the oscillating welding robot, thereby improving the welding efficiency of the oscillating welding robot.

[0043] refer to Figure 3 as well as Figure 5In some embodiments, the wrist joint 130 controlling the end of the welding torch 110 to move along the second direction B may include: firstly, obtaining the position 51 of the welding torch end corresponding to the next welding point 31 based on the position of the next welding point 31. Since the position of the end of the welding torch 110 may be a certain distance from the surface of the workpiece to be welded, the position of the next welding point 31 and the position 51 of the welding torch end corresponding to the next welding point 31 may not be the same. In order to determine how the wrist joint 130 controls the end of the welding torch 110 to move along the second direction B, it is first necessary to obtain the position 51 of the welding torch end corresponding to the next welding point 31 based on the position of the next welding point 31.

[0044] Specifically, in some embodiments, obtaining the position 51 of the welding torch end corresponding to the next welding point 31 based on the position of the next welding point 31 may include: ensuring that the next position of the wrist joint 130, the position 51 of the welding torch end corresponding to the next welding point 31, and the next welding point 31 are on the same straight line; and obtaining the position 51 of the welding torch end corresponding to the next welding point 31 based on geometric relationships through the position of the next welding point 31 and the next position of the wrist joint 130. Ensuring that the next position of the wrist joint 130, the position 51 of the welding torch end corresponding to the next welding point 31, and the next welding point 31 are on the same straight line minimizes the distance between the end of the welding torch 120 and the next welding point 31, thus minimizing the distance between the actual position of the end of the welding torch 120 and the welding position of the next welding point 31. This can improve the welding quality of the oscillating welding robot to a certain extent and avoid unnecessary oscillating welding movements controlled by the wrist joint 130, thereby improving welding efficiency.

[0045] refer to Figure 5 In some embodiments, the specific method for obtaining the position 51 of the welding torch end corresponding to the next welding point 31 based on the geometric relationship between the position of the next welding point 31 and the next position of the wrist joint 130 can be achieved by establishing a spatial coordinate system and performing coordinate calculations. The following will describe in detail how to obtain the position 51 of the welding torch end corresponding to the next welding point 31 based on the geometric relationship between the position of the next welding point 31 and the next position of the wrist joint 130.

[0046] In some embodiments, a robot base coordinate system can be established based on the oscillating welding robot. The controller of the oscillating welding robot can acquire the position coordinates of the wrist joint 130 relative to the robot base coordinate system and the position coordinates of the welding torch 110 end face relative to the robot base coordinate system. (Reference) Figure 5The welding torch 110 is positioned perpendicular to the surface of the workpiece to be welded, and the point where the end of the welding torch 110 is directly welded to the surface of the workpiece is designated as the vertical welding point 32. If, when the welding torch 110 is perpendicular to the workpiece, there is still a certain distance between the end of the welding torch 110 and the workpiece, then the vertical welding point 32 is the position of the end of the welding torch 110 when it is perpendicular to the workpiece. The next position of the wrist joint 130 obtained above is... Figure 5 The position of the wrist joint 130, the next welding point 31 is the next welding point 31 on the oscillating welding path 30 that was known in the previous text. Based on the above vertical welding point 32, the position of the wrist joint 130 and the next welding point 31, the position of the end of the welding gun 110 at this time can be obtained.

[0047] Specifically, the controller obtains the coordinates of the wrist joint 130 as (X0, Y0, Z0) based on the robot's base coordinate system, the coordinates of the vertical welding point 32 as (X1, Y1, Z1), and the coordinates of the next welding point 31 as (X2, Y2, Z2). The corresponding position coordinates of the welding torch 110's end are set to (Q...). X Q Y Q Z ).according to Figure 5 The geometric principle of similar triangles can be expressed by the following formula:

[0048] (X0-X2) 2 +(Y0-Y2) 2 +(Z0-Z2) 2 =R1 2 ;

[0049] (X0-Q X ) 2 +(Y0-Q Y ) 2 +(Z0-Q Z ) 2 =R 2 ;

[0050] (Q X -X2) / (X0-X2)=(Q Y -Y2) / (Y0-Y2)=(Q Z -Z2) / (Z0-Z2);

[0051] Where R1 represents the distance from the next welding point to the wrist joint 130, and R represents the radius of the welding torch 110 trajectory, which is also the length of the welding torch 110, or the distance from the end of the welding torch 110 to the wrist joint 130. Therefore, the coordinates of the position 51 of the end of the welding torch 110 are (Q X Q Y Q Z The following three equations are given:

[0052] Q X =X0-(X0-X2)*(R / R1);

[0053] Q Y =Y0-(Y0-Y2)*(R / R1);

[0054] Q Z =Z0-(Z0-Z2)*(R / R1);

[0055] The above calculation formula allows us to obtain the position 51 of the welding torch end corresponding to the next welding point 31 based on the geometric relationship between the position of the next welding point 31 and the next position of the wrist joint 130. The position 51 of the welding torch end corresponding to the next welding point 31 will be programmed into the controller. Based on the distance between the next welding point 31 and the welding path 10, the controller can determine the distance that the welding torch 110 moves when it leaves the welding path 10.

[0056] refer to Figure 3 After determining the position 51 of the welding torch end corresponding to the next welding point 31, a position vector 50 can be obtained based on the position 51 of the welding torch end corresponding to the next welding point 31 and the next position of the wrist joint 130. Then, robot inverse kinematics is performed based on the position vector 50 to obtain the angle of the wrist joint 130 corresponding to the next welding point 31. Robot inverse kinematics is the process of solving for the joint position given the end-effector position and orientation, as well as the geometric parameters of all links. In this embodiment, given the position 51 of the welding torch end corresponding to the next welding point 31 and the next position of the wrist joint 130, the angle and orientation of the wrist joint 130 can be calculated using robot inverse kinematics.

[0057] In some embodiments, before calculating the angular orientation of the wrist joint 130 based on the robot's inverse kinematics, a three-dimensional Cartesian coordinate system can be established with the wrist joint 130 position as the origin. This Cartesian coordinate system has an X-axis, a Y-axis, and a Z-axis, and the welding torch 110 forms angles with each of these axes. The angular orientation of the wrist joint 130 includes the three angles between the welding torch and the X-axis, Y-axis, and Z-axis.

[0058] In some embodiments, to solve the angular orientation of the wrist joint 130, one of the three included angles between the welding torch and the X-axis, Y-axis and Z-axis can be fixed first, thereby determining a set of inverse kinematic equations for solving the remaining two included angles. At this time, the remaining two included angles have a unique solution, and the controller can perform inverse kinematics solution more quickly and easily.

[0059] Specifically, in some embodiments, the inverse kinematics solution based on the position vector 50 to obtain the angle of the wrist joint 130 corresponding to the next welding point 31 may include: establishing a three-dimensional rectangular coordinate system with the wrist joint 130 as the origin, wherein the X-axis of the three-dimensional rectangular coordinate system can be parallel to the welding path 10, and the included angles between the welding torch 110 connected to the wrist joint 130 and the three axes of the three-dimensional rectangular coordinate system are angle one, angle two and angle three, respectively, wherein the included angle between the welding torch 110 and the X-axis is angle one; obtaining the distance between the wrist joint 130 and the tooling to be welded as the first distance d; fixing angle one unchanged, and obtaining angle two and angle three of the wrist joint 130 corresponding to the next welding point 31 based on the position vector 50 and the first distance d. Since the X-axis is parallel to the welding path 10, and the wrist joint 130 controls the end of the welding torch 110 to move along the second direction B, the angle between the welding torch 110 connected to the wrist joint 130 and the X-axis of the three-dimensional rectangular coordinate system is fixed at 90°. The welding torch 110 connected to the wrist joint 130 is perpendicular to the X-axis, and as the wrist joint 130 drives the welding torch 110 to swing along the second direction B, the angles between the welding torch 110 connected to the wrist joint 130 and the Y-axis and Z-axis continuously change. Given the position 51 of the end of the welding torch 110 corresponding to the next welding point and the position of the wrist joint 130, a unique solution can be obtained from the robot's inverse kinematics to solve for the angles between the wrist joint 130 and the Y-axis, and between the wrist joint 130 and the Z-axis, thus obtaining the angle of the wrist joint 130.

[0060] In other embodiments, the established three-dimensional rectangular coordinate system may not have an axis parallel to the welding path 10, and the origin of the three-dimensional rectangular coordinate system may be a point other than the wrist joint 130. The three-dimensional rectangular coordinate system only serves as a spatial reference.

[0061] Let angle 1 be denoted as 1, angle 2 as 2, and angle 3 as 3. According to the robot inverse kinematics formula, the following equation defines the position (Q) of the welding torch 110 end relative to the robot base coordinate system. X Q Y Q Z ):

[0062] Q X = (cos2cos3cos1-sin2sin1)*T X -(cos2cos3cos1+sin2sin1)*T Y -cos2cos3*T Z +cos2cos3*d1;

[0063] Q Y =(sin2cos3cos1-cos2sin1)*T X -(sin2cos3sin1+cos2cos1)*TY -sin2sin3*T Z +sin2sin3*d1;

[0064] Q Z = -sin3cos1*T X +sin3sin1*T Y +cos3*T Z +cos3*d;

[0065] Wherein, the first distance d is the distance between the wrist joint 130 and the welding fixture, which can be obtained from the controller, T X T Y And T Z The coordinates of the welding torch 110 tip relative to the aforementioned three-dimensional rectangular coordinate system can also be obtained by the controller. Furthermore, the distance R1 from the next welding point to the wrist joint 130 and the radius R of the welding torch 110 trajectory can be expressed by the following equations:

[0066] R = sqrt(d1*d1 + R1*R1 + 2*d*T) Z );

[0067] R1 = sqrt(T) X *T X +T Y *T Y +T Y *T Y );

[0068] Based on the above robot inverse kinematics solution formula, a unique solution for the angle and orientation of the wrist joint 130 can be obtained when the position of the next welding point 31 is known and the next position of the wrist joint 130 is known. Thus, the change of the angle of the wrist joint 130 can be controlled by the controller to achieve the purpose of swing welding motion in the second direction B.

[0069] After solving the angle of the wrist joint 130 corresponding to the next welding point based on the robot's inverse kinematics, the wrist joint 130 can be rotated by the controller to adjust to the angle of the wrist joint 130 corresponding to the next welding point, thereby controlling the end of the welding torch 110 to move along the second direction B.

[0070] In summary, the embodiments of this disclosure first determine the oscillating welding path based on a preset welding path and relevant parameters input by the user. Then, the position of the next welding point is determined based on the oscillating welding path. Based on the position of the next welding point, the next position of the wrist joint and the position of the welding torch tip corresponding to the next welding point can be determined. Based on the position of the welding torch tip corresponding to the next welding point and the next position of the wrist joint, the angle of the wrist joint can be determined. When the next position of the wrist joint is known, the controller can cause the robotic arm structure of the oscillating welding robot to control the wrist joint to move along the first direction to the next position of the wrist joint. When the angle of the wrist joint corresponding to the next welding point is known, the controller can control the wrist joint to rotate to the wrist joint angle corresponding to the next welding point, so that the welding torch tip moves along the second direction to the position of the welding torch tip corresponding to the next welding point. This enables movement in the first direction and oscillation in the second direction, ultimately controlling the oscillating welding robot to perform oscillating welding motion along the oscillating welding path.

[0071] This disclosure provides a method for controlling the oscillating welding motion of a oscillating welding robot. First, a welding path is preset on the workpiece to be welded, along with parameters of the welding torch relative to the welding path. The extension direction of the welding path is a first direction, and a direction parallel to the surface of the workpiece and perpendicular to the welding path is a second direction. An oscillating welding path is obtained based on the welding path and the parameters of the welding torch relative to the welding path. The oscillating welding path includes multiple continuous welding points. The robotic arm structure of the oscillating welding robot controls the wrist joint to move along the first direction, and the wrist joint controls the end of the welding torch to move along the second direction. The robotic arm structure and the wrist joint jointly control the movement of the end of the welding torch, enabling the oscillating welding robot to weld along the oscillating welding path on the surface of the workpiece. Thus, the periodic oscillation of the welding torch end in the second direction does not need to be controlled by the robotic arm structure, and the robotic arm structure does not need to oscillate in the second direction. Therefore, the oscillating welding motion of the welding torch is not affected by the large mass of the robotic arm structure, and the frequency of the oscillating welding motion can be increased. The wrist joint can control the end of the welding torch to fold back and forth multiple times in a short period of time in the second direction, thereby improving the welding efficiency of the oscillating welding robot.

[0072] Accordingly, another embodiment of this disclosure also provides a swivel welding robot system, which can implement the method for controlling the swivel welding robot's swivel welding motion described in the above embodiments. The swivel welding robot system provided in another embodiment of this disclosure will be described in detail below with reference to the accompanying drawings. For parts that are the same as or corresponding to the previous embodiment, please refer to the corresponding descriptions of the foregoing embodiments; detailed descriptions will not be repeated below.

[0073] Figure 6 This is a schematic diagram of the structure of a welding robot system provided in one embodiment of the present disclosure.

[0074] refer to Figure 6The oscillating welding robot system includes: a base 100; a robotic arm structure 120, one end of which is connected to the base 100, and the other end of which has a wrist joint 130; a welding torch 110, which is connected to the wrist joint 130; and a controller 140, which controls the rotation of the wrist joint 130 to make the welding torch 110 oscillate. The controller 140 is also used to control the movement of the robotic arm structure 120, and the direction of movement of the robotic arm structure 120 is different from the direction of oscillation of the welding torch 110.

[0075] It should be noted that the direction of movement of the robotic arm structure 120 can be the same as the extension direction of the weld seam to be welded, and the direction of rotation of the wrist joint 130 to swing the welding torch 110 can be perpendicular to the extension direction of the weld seam to be welded, that is, the direction of rotation of the wrist joint 130 to swing the welding torch 110 can be perpendicular to the direction of movement of the robotic arm structure 120. During the oscillating welding motion of the oscillating welding robot, the relatively heavy robotic arm structure 120 only moves in the extension direction of the weld seam and does not swing in the direction perpendicular to the weld seam. Swinging in the direction perpendicular to the weld seam usually requires a large speed and a high frequency. The oscillation in the direction perpendicular to the weld seam achieved by the rotation of the wrist joint 130 can avoid the large mass of the robotic arm structure 120 affecting the speed and frequency of the oscillating welding motion, thereby improving the efficiency of the oscillating welding robot.

[0076] In some embodiments, the robotic arm structure 120 may include a large arm 121, a forearm 122, and a drive housing 123. One end of the large arm 121 is connected to the base 100, one end of the forearm 122 has a wrist joint 130, and the drive housing 123 connects the forearm 122 and the large arm 121. That is, from the base 100 outwards, the structure may consist of: large arm 121, drive housing 123, forearm 122, wrist joint 130, and welding torch 110. When the controller 140 controls the robotic arm 120 structure to move along the extension direction of the weld, it can first control the large arm 121 to move along the extension direction of the weld. The large arm 121 will drive the drive housing 123 and the forearm 122 to move along the extension direction of the weld. Furthermore, if there is a certain offset between the welding robot and the weld, the forearm 122 connected to the drive housing 123 can also rotate to adjust its direction, so that the welding robot can correspond to the weld, and the welding robot has higher flexibility.

[0077] This disclosure provides a oscillating welding robot system, including: a base connected to one end of a robotic arm structure; a wrist joint at the other end of the robotic arm structure; a welding torch connected to the wrist joint; and a controller for controlling the rotation of the wrist joint to cause the welding torch to oscillate. The controller also controls the movement of the robotic arm structure, the direction of movement of the robotic arm structure being different from the oscillation direction of the welding torch. Thus, the oscillation of the welding torch is achieved by the rotation of the wrist joint, without requiring the robotic arm structure to oscillate. Therefore, the oscillating welding motion of the welding torch is not affected by the large mass of the robotic arm structure, the frequency of the oscillation motion can be increased, and the wrist joint can control the end of the welding torch to fold back and forth multiple times in a short period of time in a second direction, thereby improving the welding efficiency of the oscillating welding robot.

[0078] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of this disclosure. Any person skilled in the art can make their own modifications and alterations without departing from the spirit and scope of this disclosure; therefore, the scope of protection of this disclosure should be determined by the scope defined in the claims.

Claims

1. A method for controlling the oscillating welding motion of an oscillating welding robot, characterized in that, include: A welding path is preset on the fixture to be welded, and the parameters of the welding torch relative to the welding path are defined. The extension direction of the welding path is a first direction, and the direction parallel to the surface of the fixture to be welded and perpendicular to the welding path is a second direction. The oscillating welding path is obtained based on the welding path and the parameters of the welding torch relative to the welding path. The oscillating welding path is present on both sides of the welding path, and the oscillating welding path includes multiple continuous welding points. The robotic arm structure of the oscillating welding robot controls the wrist joint to move along a first direction, and the wrist joint controls the end of the welding torch to move along a second direction. The robotic arm structure and the wrist joint jointly control the movement of the end of the welding torch, so that the oscillating welding robot welds on the surface of the workpiece to be welded along the oscillating welding path. The wrist joint controls the movement of the welding torch tip in the second direction, including: The next position of the wrist joint, the position of the welding torch tip corresponding to the next welding point, and the next welding point are all on the same straight line; according to geometric relationships, the position of the welding torch tip corresponding to the next welding point is obtained by using the position of the next welding point and the next position of the wrist joint; A position vector is obtained based on the position of the end of the welding torch corresponding to the next welding point and the next position of the wrist joint; Inverse kinematics is performed based on the position vector to obtain the wrist joint angle corresponding to the next welding point; Controlling the wrist joint rotation to adjust to the wrist joint angle corresponding to the next welding point, thereby controlling the end of the welding torch to move along the second direction.

2. The method for controlling the oscillating welding motion of a oscillating welding robot according to claim 1, characterized in that, The wrist joint moves along a wrist joint path, the wrist joint path extends along the first direction, and the robotic arm structure of the oscillating welding robot controls the wrist joint to move along the first direction by: Obtain the next welding point in the welding path, and obtain the next position of the wrist joint based on the position of the next welding point. The next position of the wrist joint is located at the projection position of the next welding point on the wrist joint path.

3. The method for controlling the oscillating welding motion of a oscillating welding robot according to claim 1, characterized in that, Inverse kinematics is performed based on the position vector to obtain the wrist joint angle corresponding to the next welding point, including: A three-dimensional rectangular coordinate system is established with the wrist joint as the origin. The X-axis of the three-dimensional rectangular coordinate system is parallel to the welding path. The angles between the welding gun connected to the wrist joint and the three axes of the three-dimensional rectangular coordinate system are angle one, angle two and angle three, respectively. Among them, the angle between the welding gun and the X-axis is angle one. The distance between the wrist joint and the welding fixture is defined as the first distance. With angle one fixed, angles two and three of the wrist joint corresponding to the next welding point are obtained based on the position vector and the first distance.

4. The method for controlling the oscillating welding motion of a oscillating welding robot according to claim 1, characterized in that, The parameters of the welding torch relative to the welding path include at least: the maximum distance between the welding point and the welding path on both sides of the welding path, the frequency of the oscillating welding motion, and acceptable tolerances.

5. The method for controlling the oscillating welding motion of a oscillating welding robot according to claim 1, characterized in that, The welding path is a straight line.

6. The method for controlling the oscillating welding motion of a oscillating welding robot according to claim 5, characterized in that, The sway welding path is a sine curve.

7. A tack welding robot system, characterized in that, include: Base; A robotic arm structure, one end of which is connected to the base, and the other end of which has a wrist joint; A welding torch, which is connected to the wrist joint; A controller is used to control the rotation of the wrist joint to make the welding torch swing, and the controller is also used to control the movement of the robotic arm structure, wherein the direction of movement of the robotic arm structure is different from the swing direction of the welding torch; The controller is used to perform the method of controlling the oscillating welding robot's oscillating welding motion as described in any one of claims 1 to 6.

8. The oscillating welding robot system according to claim 7, characterized in that, The robotic arm structure includes: The main arm, one end of which is connected to the base; Forearm, one end of which has the wrist joint; A drive housing that connects the forearm and the upper arm.

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