Crossing oscillation device and process for industrial arc welding robot

Abstract

The application discloses an industrial arc welding robot cross swinging device and process, relates to the arc welding technical field, and the swinging device comprises an arc welding robot base, a plurality of sets of swing arm mechanisms are arranged on the arc welding robot base, and two adjacent swing arm mechanisms are connected through a joint mechanism; a welding gun body is fixedly arranged at a terminal swing arm mechanism, a welding wire is arranged at an output end of the welding gun body, and the swing arm mechanism is used for driving the welding gun body to perform cross left-right angle swinging movement along a welding seam advancing direction; the application can effectively ensure that a welding gun nozzle and the welding wire are far away from a base material during swinging, and prevent the welding wire from being in contact with the edge of the base material in the vertical direction to cause wire explosion and arc breaking; by changing the welding gun orientation angle, the welding wire can be directed to the left and right roots of the welding seam, and the penetration and welding strength of the left and right roots are increased; the application defines a mathematical expression of a swinging track in X+, Y+ and Z+ three directions, and the expression can be used for accurately controlling the movement of the robot, so that high-quality welding seam swinging welding is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of arc welding, in particular to an industrial arc welding robot cross swing device and process. BACKGROUND

[0002] The arc welding robot refers to an industrial robot used for automatic arc welding. The arc welding robot is generally composed of a teaching box, a control panel, a robot body, an automatic wire feeder, a welding power source and the like. The working principle is roughly as follows: the robot is guided by the user to operate step by step according to the actual task. During the guiding process, the position, posture, motion parameters, welding parameters and the like of each action of the teaching are automatically memorized, and a program for continuously executing all operations is automatically generated. After completing the teaching, only a start command is given to the robot, and the robot will accurately complete all operations step by step according to the teaching action.

[0003] During welding, the arc welding robot uses an electric arc as a heat source for welding, and continuously sprays protective gas from the nozzle of the spray gun to isolate air from the molten metal in the welding area, so as to protect the electric arc and the liquid metal in the welding pool from being polluted by oxygen, nitrogen, hydrogen and the like in the atmosphere, thereby improving the welding quality.

[0004] The swing welding of the arc welding robot is a method of periodically swinging the welding gun left and right at a specific angle during welding to increase the width of the welding bead and improve the welding strength. Referring to the drawings of the specification Figure 1 and Figure 2 , the conventional swing welding is to make the welding gun fixed in the plane to move left and right periodically. The disadvantage of this swing method is that it is easy to cause the contact collision of the welding gun nozzle, welding wire and welding base material, which directly affects the welding forming and internal quality effect of the weld. SUMMARY

[0005] The purpose of the present application is to provide an industrial arc welding robot cross swing device and process, which solves the following technical problems:

[0006] The conventional swing welding is to make the welding gun fixed in the plane to move left and right periodically. The disadvantage of this swing method is that it is easy to cause the contact collision of the welding gun nozzle, welding wire and welding base material, which directly affects the welding forming and internal quality effect of the weld.

[0007] The purpose of the present application can be achieved by the following technical solutions:

[0008] An industrial arc welding robot cross swing device, comprising an arc welding robot base, a plurality of groups of swing arm mechanisms are arranged on the arc welding robot base, and two adjacent swing arm mechanisms are connected through a joint mechanism.

[0009] The welding gun body is fixed at the end of the swing arm mechanism, and the output end of the welding gun body is provided with a welding wire.

[0010] Preferably, the swing range of the left-right angle is -10°-10°.

[0011] A swing process of an industrial arc welding robot cross swing device, comprising the following steps:

[0012] Establishing a weld swing coordinate system;

[0013] Determining a swing form and a swing formula;

[0014] Increasing left-right angle swing and performing interpolation operation on X+ direction rotation angle.

[0015] Preferably, the establishment of the weld swing coordinate system comprises the following steps:

[0016] Defining the orientation of the welding gun body 1 as Z+ direction, the weld advancing direction as X+ direction, and the left-right direction of the welding gun body 1 as Y+ direction;

[0017] According to the right-hand rule and the optimized X+, Y+, and Z+ directions, a weld swing coordinate system is established, which is used to control the movement of the welding gun body on the weld;

[0018] Defining the position offset relative to the robot base coordinate system and the rotation matrix ;

[0019] Defining the weld swing coordinate system expression , and the weld swing coordinate system expression is: .

[0020] Preferably, the swing form includes but is not limited to sine wave, triangular wave or square wave.

[0021] Preferably, the determination of the swing form and the swing formula comprises the following steps:

[0022] Based on the swing frequency f and the swing amplitude A, the basic parameters of the swing and the value of the swing position in the Y+ direction are determined; specifically, based on the swing frequency f and the swing amplitude A, the basic parameters of the swing and the value of the swing position in the Y+ direction are determined; wherein the swing frequency f is the number of swings per unit time, and the swing amplitude A is the maximum deviation distance of the swing from the center line, these parameters jointly determine the speed and amplitude of the swing, which has important influence on the welding effect; in the weld swing coordinate system, the Y+ direction usually represents the transverse position of the weld. This step is to determine the specific position or range of the swing in the Y+ direction, to ensure that the swing can cover the entire weld width or follow the predetermined trajectory;

[0023] The swing trajectory is represented based on the weld swing coordinate system, and expressions of the swing trajectory in each direction of the weld swing coordinate system X+, Y+ and Z+ are defined.

[0024] Specifically, the swing trajectory is the actual movement path of the welding torch when the robot performs swing welding. This step is to analyze and determine the shape and characteristics of the swing trajectory to ensure that the welding process can proceed in the predetermined manner; define the mathematical expressions of the swing trajectory in the X+, Y+ and Z+ three directions, which can be used to accurately control the movement of the robot to achieve high-quality weld swing welding;

[0025] Preferably, the expressions of the swing trajectory in each direction of the weld swing coordinate system are as follows:

[0026]

[0027] wherein F is a generation formula of the swing trajectory, and the generated formula is a sine swing formula;

[0028] The sine swing formula is

[0029] Based on the sine swing formula and the expressions, a superposition matrix of the swing trajectory based on the weld swing coordinate system is obtained defined as follows:

[0030]

[0031] wherein represents the offset of the swing position estimation relative to the robot base coordinate system, represents the rotation matrix thereof.

[0032] Preferably, is a rotation matrix of the weld swing coordinate system X+ direction around the robot base coordinate system, and the expression is as follows:

[0033]

[0034] wherein is a generation formula of the swing welding in the X+ direction posture.

[0035] Preferably, when the robot is not swinging and moving along the main weld, the kinematic formula between the robot end trajectory and the robot joint mechanism is as follows:

[0036]

[0037] wherein θ is the angle of each joint mechanism of the robot, represents the posture of the robot end in the Cartesian space position, ​a rotation matrix of the welding bead coordinate system relative to the robot base coordinate system, a position offset of the welding bead coordinate system relative to the robot base coordinate system, the superposition formula of the swing trajectory on the trajectory of the main weld is as follows:

[0038]

[0039]

[0040] wherein, a position offset of the welding bead coordinate system after superimposing the swing trajectory, a rotation matrix of the welding bead coordinate system after superimposing the swing trajectory, that is, the final calculation matrix.

[0041] Preferably, the final calculation matrix is converted into the robot base coordinate system, the forward and inverse kinematics models of the robot are established, and the actual angles of each joint mechanism are obtained through inverse solution operation:

[0042] .

[0043] The beneficial effects of the present application are:

[0044] (1) The present application can effectively ensure that the welding torch nozzle and the welding wire are far away from the base material during the swing process, prevent the vertical direction of the welding wire and the edge of the base material from contacting to cause wire explosion and arc breakage; specifically, when driving the welding torch body to weld, on the basis of the original conventional welding torch body fixed plane swing, the left and right angular swing of the welding torch body, also called the operation angle or the inclination angle, is increased through the swing arm mechanism and the joint mechanism, so that the position of the welding wire end changes during the swing process, and the posture of the welding torch body also changes in real time according to the specified angle; ensure that the nozzle and the welding wire of the welding torch body are far away from the base material during the swing process, prevent the vertical direction of the welding wire and the edge of the base material from contacting to cause wire explosion and arc breakage; at the same time, the posture of the welding torch body is directly related to the welding quality, changing the orientation angle of the welding torch body can make the welding wire face the left and right roots of the weld, increase the penetration depth and welding strength of the left and right roots,

[0045] (2) The present application can increase the penetration and welding strength of the left and right roots by changing the angle of the welding torch towards the weld, specifically, according to the right-hand rule, after determining the X+, Y+ and Z+ directions, a complete rectangular coordinate system can be established, which is used to describe the position and shape of the weld, as well as the swing of the welding torch body relative to the weld, the weld swing coordinate system is usually used to control the precise movement of the welding torch body 1 on the weld to achieve high-quality welding; the swing trajectory is the actual movement path of the welding torch when the robot performs swing welding, this step is to analyze and determine the shape and characteristics of the swing trajectory to ensure that the welding process can be carried out in the predetermined manner; define the mathematical expressions of the swing trajectory in the X+, Y+ and Z+ directions, these expressions can be used to accurately control the movement of the robot to achieve high-quality weld swing welding;

[0046] (3) The present application solves the problem of root fusion of the right-angle edge weld, reduces the rework caused by root quality problems, improves the welding quality and efficiency;

[0047] (4) The present application determines the basic parameters of the swing and the value of the swing position in the Y+ direction based on the swing frequency f and the swing amplitude A; wherein the swing frequency f is the number of swings per unit time, and the swing amplitude A is the maximum deviation distance of the swing from the center line, these parameters together determine the speed and amplitude of the swing, which has important influence on the welding effect; in the weld swing coordinate system, the Y+ direction usually represents the transverse position of the weld. This step is to determine the specific position or range of the swing in the Y+ direction to ensure that the swing can cover the entire weld width or follow the predetermined trajectory. BRIEF DESCRIPTION OF DRAWINGS

[0048] The present application will be further described below with reference to the accompanying drawings.

[0049] Figure 1 is a structural schematic diagram of the welding torch moving along the weld advancing direction;

[0050] Figure 2 is a structural schematic diagram of the welding torch moving periodically in the fixed plane in the prior art;

[0051] Figure 3 is a structural schematic diagram of the welding torch moving along the increased left and right angle swing of the present application;

[0052] Figure 4 is a structural schematic diagram of the arc welding robot of the present application;

[0053] Figure 5 is a flowchart of the cross-swing process of the industrial arc welding robot of the present application.

[0054] In the figure: 1, welding torch body; 2, arc welding robot base; 101, welding wire; 201, swing arm mechanism; 202, joint mechanism. DETAILED DESCRIPTION

[0055] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0056] Embodiment 1

[0057] Please refer to Figure 3 The present application is a kind of industrial arc welding robot cross swing device, including arc welding robot base 2, arc welding robot base 2 is laid on several groups of swing arm mechanism 201, two groups of adjacent swing arm mechanism 201 are connected through joint mechanism 202, joint mechanism 202 is provided with servo drive equipment, in order to drive swing arm mechanism 201 rotates around joint mechanism 202;Specifically, the arc welding robot base 2 is set as a rotary base, in order to drive swing arm mechanism 201 rotates in a circle.

[0058] It should be noted that the industrial arc welding robot of the present embodiment is a 6-axis robot.

[0059] In the present embodiment, please refer to Figure 4 The swing arm mechanism 201 at the end is fixedly arranged with a welding torch body 1, and the output end of the welding torch body 1 is provided with a welding wire 101. The swing arm mechanism 201 is used to drive the welding torch body 1 to perform cross swing movement along the welding seam advancing direction.

[0060] Specifically, when driving the welding torch body 1 to weld, on the basis of the original conventional fixed plane swing of the welding torch body 1, the swing arm mechanism 201 and the joint mechanism 202 are cooperated to increase the left and right angular swing of the welding torch body, also known as the operating angle or the inclination angle, so that the position of the welding wire 101 at the end changes, and the posture of the welding torch body 1 also changes in real time according to the specified angle during the swing process. It is ensured that the nozzle of the welding torch body 1 and the welding wire 101 are away from the base material during the swing process, to prevent the vertical direction of the welding wire 101 and the edge of the base material from contacting to cause wire explosion and arc breaking. At the same time, the posture of the welding torch body 1 is directly related to the welding quality. By changing the orientation angle of the welding torch body 1, the welding wire 101 can be directed to the left and right roots of the weld, to increase the penetration depth and welding strength of the left and right roots.

[0061] In this embodiment, when the left-right angle is set to 0°, the posture of the welding torch body 1 remains unchanged during the swinging process, and is always perpendicular to the weld. When the left-right angle is not 0°, the posture of the welding torch body 1 changes during the swinging process. The left-right angle is the maximum angle of the welding torch body 1 during swinging. The range of the left-right angle is -10°-10°.

[0062] Embodiment 2

[0063] Based on Embodiment 1, please refer to Figure 5 An industrial arc welding robot cross-swing process, comprising the following steps:

[0064] S100, establishing a weld swing coordinate system;

[0065] Specifically, please refer to Figure 1 Establishing the weld swing coordinate system comprises the following steps:

[0066] S101, defining the orientation of the welding torch body 1 as the Z+ direction, the weld advancing direction as the X+ direction, and the left-right direction of the welding torch body 1 as the Y+ direction;

[0067] Wherein, the Z+ direction refers to the direction of the welding torch nozzle, which is usually defined as the positive direction of the Z axis. During the welding process, the welding torch moves along this direction. The X+ direction is the direction of the welding speed, that is, the direction of the welding torch body 1 moving on the workpiece. In this embodiment, it is defined as the positive direction of the X axis. The Y+ direction is perpendicular to the welding torch orientation (Z+) and the welding advancing direction (X+). Based on the right-hand rule (the right thumb points to Z+, the index finger points to X+, and the middle finger points to Y+), the positive direction of the Y axis can be obtained;

[0068] It should be noted that after the Z+ and Y+ directions are determined, the X+ direction needs to be adjusted again to ensure that it is a unit vector and is orthogonal to the Y and Z axes. Specifically, this is to ensure the accuracy of the coordinate system, because in actual operation, due to various factors (such as mechanical errors, workpiece deformation, etc.), the initially defined X+ direction is not completely accurate;

[0069] S102, establishing a weld swing coordinate system according to the right-hand rule and the optimized X+, Y+, and Z+ directions;

[0070] Specifically, according to the right-hand rule, after the X+, Y+, and Z+ directions are determined, a complete rectangular coordinate system can be established. This coordinate system is used to describe the position and shape of the weld, as well as the swinging of the welding torch body relative to the weld. The weld swing coordinate system is usually used to control the precise movement of the welding torch body 1 on the weld to achieve high-quality welding;

[0071] In addition, it should be noted that the swing method of the welding torch body 1 largely depends on the direction of the TCP (Tool Center Point) tool coordinate system, therefore, it is necessary to set a relatively high TCP accuracy to ensure the accuracy of the coordinate system;

[0072] S103, define the position offset relative to the robot base coordinate system and the rotation matrix ;

[0073] Specifically, the position offset : This is the position offset of the weld swing coordinate system origin relative to the robot base coordinate system origin, which describes the position of the weld in the entire workspace.

[0074] Rotation matrix : This is the rotation matrix of the weld swing coordinate system relative to the robot base coordinate system, which describes the orientation of the weld swing coordinate system relative to the robot base coordinate system;

[0075] S104, define the weld swing coordinate system expression , the weld swing coordinate system expression is used to guide the motion control of the welding robot to achieve accurate swing welding of the weld, and the weld swing coordinate system expression is as follows:

[0076]

[0077] S200, determine the swing form and swing formula; wherein the swing form includes but is not limited to sine wave, triangular wave or square wave;

[0078] Specifically, the determination of the swing form and the swing formula includes the following steps:

[0079] S201, determine the basic parameters of the swing and the numerical value of the swing position in the Y+ direction based on the swing frequency f and the swing amplitude A; wherein the swing frequency f is the number of swings per unit time, and the swing amplitude A is the maximum deviation distance of the swing from the center line, these parameters together determine the speed and amplitude of the swing, which has important influence on the welding effect; In the weld swing coordinate system, the Y+ direction usually represents the transverse position of the weld. This step is to determine the specific position or range of the swing in the Y+ direction to ensure that the swing can cover the entire weld width or follow the predetermined trajectory;

[0080] S202, consider the robot swing trajectory, the swing trajectory is represented based on the weld swing coordinate system, and the expressions of the swing trajectory in the X+, Y+ and Z+ directions of the weld swing coordinate system are as follows:

[0081]

[0082] Wherein, F is the generation formula of the swing trajectory, and the generated formula is a sine swing formula; the sine swing formula is ; based on the sine swing formula and each expression, a superposition matrix of the swing trajectory based on the weld swing coordinate system is obtained defined as follows:

[0083]

[0084] Wherein, represents the swing position estimation relative to the robot base coordinate system, represents the rotation matrix thereof.

[0085] Specifically, the swing trajectory is the actual moving path of the welding gun when the robot performs swing welding, and this step is to analyze and determine the shape and characteristics of the swing trajectory to ensure that the welding process can be carried out in the predetermined manner; the mathematical expressions of the swing trajectory in the X+, Y+ and Z+ directions are defined, which can be used to accurately control the movement of the robot to achieve high-quality weld swing welding;

[0086] In this embodiment, the mathematical expressions of the weld swing trajectory in the X+, Y+ and Z+ directions of the weld swing coordinate system are derived by analyzing the kinematics and dynamics characteristics of the welding robot, combined with the weld shape and size.

[0087] S300, increase the left and right angle swing, and interpolate the X+ direction rotation angle;

[0088] Specifically, is the generation formula of the swing welding in the X+ direction posture; is the rotation matrix of the weld swing coordinate system X+ direction around the robot base coordinate system, and its expression is as follows:

[0089]

[0090] In this embodiment, when the robot is not swinging, the kinematics formula between the robot end trajectory and the robot joint mechanism 202 when moving along the main weld is as follows:

[0091]

[0092] Wherein, θ is the angle of each joint mechanism 202 of the 6-axis robot, represents the posture of the robot end in the Cartesian space position, is the rotation matrix of the weld coordinate system relative to the robot base coordinate system, is the position offset of the weld coordinate system relative to the robot base coordinate system, and the swing trajectory is superimposed on the trajectory of the main weld, and the superposition formula is as follows:

[0093]

[0094]

[0095] wherein, is the position offset after superimposing the weaving trajectory on the welding bead coordinate system, is the rotation matrix after superimposing the weaving trajectory on the welding bead coordinate system, that is, the final calculation matrix. The final calculation matrix is converted into the robot base coordinate system, the forward and inverse kinematics models of the robot are established, and the inverse solution operation is performed to obtain the actual angles of each joint mechanism 202:

[0096] .

[0097] In the description of the present application, it should be understood that the terms "upper", "lower", "left", "right", etc. indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, and a particular orientation configuration and operation, therefore, it cannot be understood as a limitation on the present application. In addition, "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited by "first", "second" can explicitly or implicitly include one or more features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0098] In the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "mounting", "connecting", "connecting" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication between two elements inside. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0099] The above describes one embodiment of the present application in detail, but the content described is only the preferred embodiment of the present application, and cannot be considered as limiting the scope of the present application. Any equivalent changes and improvements made within the scope of the present application shall still belong to the patent coverage of the present application.

Claims

1. A swinging process for a cross swinging device of an industrial arc welding robot, the swinging device including an arc welding robot base, wherein a plurality of swing arm mechanisms are arranged on the arc welding robot base, and two adjacent swing arm mechanisms are connected by a joint mechanism. Its features are, The welding torch body is fixedly arranged at the end of the swing arm mechanism. The output end of the welding torch body is provided with welding wire. The swing arm mechanism is used to drive the welding torch body to swing at a cross angle along the direction of weld advance. The oscillation process includes the following steps: Establish a coordinate system for weld oscillation; Determine the swing pattern and swing formula; Add left and right angular oscillation, and perform interpolation calculations on the rotation angle in the X+ direction; The establishment of the weld seam oscillation coordinate system includes the following steps: Define the orientation of the welding torch body as the Z+ direction, the weld advance direction as the X+ direction, and the left and right directions of the welding torch body as the Y+ direction. A weld seam oscillation coordinate system is established based on the right-hand rule and the optimized X+, Y+, and Z+ directions. The weld seam oscillation coordinate system is used to control the movement of the welding torch body on the weld seam. Define the position offset relative to the robot's base coordinate system. and rotation matrix ; Define the expression for the weld seam oscillation coordinate system. Expression of weld seam oscillation coordinate system for: ; The determination of the swing form and swing formula includes the following steps: The basic parameters of the oscillation and the value of the oscillation position in the Y+ direction are determined based on the oscillation frequency f and the oscillation amplitude A. The oscillation trajectory is based on the weld oscillation coordinate system, and the expressions of the oscillation trajectory in each direction of the weld oscillation coordinate system X+, Y+ and Z+ are defined. The expressions for the oscillation trajectory in each direction of the weld oscillation coordinate system are as follows: Where F is the formula for generating the oscillation trajectory, and the generated formula is a sinusoidal oscillation formula; The formula for sinusoidal oscillation is: ; Based on the sinusoidal oscillation formula and its various expressions, the superposition matrix of the oscillation trajectory based on the weld oscillation coordinate system is obtained. The definition is as follows: in, This represents the offset of the estimated swing position relative to the robot's base coordinate system. Represents its rotation matrix Let X+ be the rotation matrix of the weld seam oscillation coordinate system about the robot's base coordinate system, and its expression is as follows: in, This is the formula for generating the attitude of the oscillating welder in the X+ direction.

2. The oscillation process of the cross-oscillation device for industrial arc welding robots according to claim 1, characterized in that, The swing range of the left and right angles is -10° to 10°.

3. The oscillation process of the cross-oscillation device for an industrial arc welding robot according to claim 1, characterized in that, When the robot is not swinging, the kinematic formulas between the robot's end effector trajectory and the robot's joint mechanism as it moves along the main weld seam are as follows: Where θ represents the angle of each joint mechanism of the robot. This represents the orientation of the robot's end effector in Cartesian space. Let be the rotation matrix of the weld coordinate system relative to the robot base coordinate system. To account for the positional offset of the weld coordinate system relative to the robot's base coordinate system, an oscillation trajectory is superimposed on the trajectory of the main weld seam. The superposition formula is as follows: in, This represents the position offset after superimposing the oscillation trajectory onto the weld coordinate system. The rotation matrix after superimposing the oscillation trajectory on the weld coordinate system is the final calculation matrix.

4. The oscillation process of the cross-oscillation device for an industrial arc welding robot according to claim 3, characterized in that, The final calculation matrix is ​​converted into the robot's base coordinate system, and the robot's forward and inverse kinematics models are established. Inverse kinematics calculations are then performed to obtain the actual angles of each joint mechanism. 。

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