Track deviation adjusting method and welding control system

Abstract

The invention discloses a track deviation adjusting method and a welding control system, and belongs to the technical field of welding robots. The method comprises the steps that S1, the deviation starting position of deviation generated by the welding robot during welding is obtained; s2, starting to execute a first adjustment process of adjusting the welding robot along a YOZ inclination angle between the Y axis and the Z axis from the offset initial position; s3, after the first adjusting process is executed, a second adjusting process for adjusting the rotating speed of the stirring head and the welding speed of the welding robot starts to be executed; and S4, after the second adjustment process is executed, returning to the step S1 to obtain the next deviation initial position. The technical scheme has the beneficial effects that the possibility of track deviation caused by the fact that welding resistance exceeds robot rigidity is avoided, the welding success rate of FSW operation is increased, and the problems of product yield and welding efficiency of a series robot FSW operation platform are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of welding robots, and particularly to a method for adjusting trajectory deviation and a welding control system. Background Art

[0002] Friction stir welding (FSW) of non-ferrous metals F riction S tir W is a technology widely used in the production of various manufacturing industries. Currently, the most popular technology is to use industrial robots as the platform for FSW, which has the advantages of flexibility and cost, especially in the application scenarios of complex three-dimensional space curve welds, and the advantages are more obvious.

[0003] A basic assumption of traditional FSW control methods is that the rigidity of the welding execution system is much greater than the welding resistance exerted by the workpiece on the welding spindle. The premise of this assumption is that the special machine tools usually used for friction stir welding have high structural rigidity, which can ensure the accurate execution of the process.

[0004] In the prior art, when using a serial robot platform for FSW operations, compared with special machine tools, the system rigidity of serial robots is poor. If traditional control principles and processes are used for welding, the complex and changeable force states during the operation often lead to the deviation of the welding path from the preset path. In addition, the processing flexibility advantage of robots makes robot FSW operations often be used to deal with welds in three-dimensional space. In order to simultaneously meet the requirements of the preset moving path and the inclination angle of the FSW stirring head, robots often need to cooperate with multi-axis motors to move, which makes the rigidity problem more prominent.

[0005] Although in addition to FSW, there are also problems of welding path deviation during the welding process of other types of robots, such as the arc welding process of large structural parts. However, the path deviation problems in the welding processes of other types are often the result of the combined effects of the accuracy problems of the robots themselves and the shape deviations of the welded objects (including processing defects, assembly errors, and thermal input deformation, etc.). The path deviation problem in robot FSW operations mainly comes from the interaction force between the FSW operation tool (mainly the stirring head) and the workpiece to be welded. Therefore, even if all the above-mentioned influencing factors are eliminated, the path deviation problem still exists during the robot FSW operation process.

[0006] The path deviation problems existing in the robot FSW operation process are specifically described below:

[0007] Such as Figure 2Shown in the figure is the schematic diagram of the movement of the stirring head when an existing serial robot performs FSW operations. Specifically, when the serial robot performs FSW operations, the forward direction of the stirring head is the positive direction of the X-axis, the side direction of the stirring head is the positive direction of the Y-axis, and the normal direction of the stirring head upward (perpendicular to the XOY plane) is the positive direction of the Z-axis. Thus, an XYZ coordinate system can be constructed based on the weld position during the welding process.

[0008] Figure 3 Shown in the figure is the operating principle of the stirring head when an existing serial robot performs FSW operations. The stirring head rotates at a high speed throughout the entire operation. Generally, the side where the linear velocity of the stirring head is in the same direction as the forward direction is called the forward side (i.e., the positive direction of the X-axis), and the opposite side is called the backward side. According to the traditional FSW operation method in the prior art, when the serial robot performs welding, the stirring head rotates and penetrates down to the weld position. The specific position is judged by a force sensor, that is, when the resistance force along the main axis direction reaches the target value, it is considered to reach the target position. Then, the robot moves forward along the forward direction of the X-axis to complete the welding operation. During the welding process, the stirring head is kept in the XOZ plane, and it has an inclination angle of 2.5° relative to the normal axis Z (depending on the specific working conditions, this angle is usually adjusted within the range of 0° to 5°).

[0009] Then, in the prior art, using the traditional FSW control method will produce typical trajectory offsets as shown in Figure 3 Shown in the figure. Specifically, during the welding process, there is a displacement between the actual position and the taught position, marked as δ. This offset appears at the beginning stage of welding, and its magnitude is related to various factors, including the material of the welding target, the welding process parameters, the rigidity of the robot, etc. Theoretically, if the rigidity of the robot is increased to the level of a special-purpose machine tool, this offset can be eliminated. However, for the current commercial applications of friction stir welding (mainly aluminum alloy welding), serial robots with a load of less than 700 kg commonly available on the market cannot provide sufficient rigid support.

[0010] Furthermore, in the existing FSW constant force control technology, the role of the force sensor is to monitor the axial force of the stirring head, that is, the change in the force in the direction at an angle of 0° to 5° with the Figure 2 Z-axis in the figure. The pressure is maintained within a certain range by adjusting the axial feed amount. The parameter control points of the existing FSW constant force control technology usually include the welding speed, the weld trajectory coordinates, and the XOZ inclination angle. The rotation speed of the stirring head is a non-independent adjustment parameter locked with the welding speed, that is, when the welding speed is adjusted, the rotation speed will also be adjusted, but the rotation speed is not adjusted separately. Then, the existing FSW constant force control technology makes the structural rigidity of the robot platform much lower than that of a special-purpose machine tool. Using such a control method will cause serious trajectory deviation and welding failure.

[0011] Figure 4This is another more extreme case where there are bead welds on the predetermined weld seam. Due to the principle characteristics of FSW, strong fixation of the welding object is required during the welding process. In actual operation, fixation points are often created by methods such as manual welding. Such fixation points do not pose difficulties for the operation of special machine tools, but for the robot FSW platform with relatively insufficient rigidity, very serious offsets will occur. That is, when encountering such fixation points, the δ value will be much larger than the case without fixation points.

[0012] In summary, the existing constant force control methods for robot FSW cannot solve the above two cases where the δ value is greater than zero, that is, the welding trajectory offset caused by the rigidity problem of the robot platform itself and the further increase in the welding trajectory offset due to bead welds. Therefore, the welding success rate will be greatly reduced, resulting in problems with product yield and welding efficiency for the series robot FSW platform compared to the FSW operation of special machine tools. Summary of the Invention

[0013] Based on the above problems existing in the prior art, a technical solution for a trajectory offset adjustment method and a welding control system is provided, aiming to adjust the trajectory offset situation in real time during the FSW operation of a series robot. The above technical solution specifically includes:

[0014] A trajectory offset adjustment method is applied to a welding robot, and the welding robot is used for FSW operation; wherein, an XYZ coordinate system is constructed based on the weld position during the welding process, where the X-axis points in the welding forward direction, and both the Y-axis and the Z-axis are perpendicular to the X-axis and the surface of the workpiece to be welded at the same time, the Y-axis is perpendicular to the XOZ plane, and the Z-axis is perpendicular to the XOY plane;

[0015] The trajectory offset adjustment method includes:

[0016] Step S1, obtaining the offset starting position where the welding robot generates an offset during welding;

[0017] Step S2, starting from the offset starting position, performing a first adjustment process of adjusting the YOZ inclination angle between the Y-axis and the Z-axis of the welding robot;

[0018] Step S3, after the first adjustment process is completed, starting to perform a second adjustment process of adjusting the rotational speed of the stirring head and the welding speed of the welding robot;

[0019] Step S4, after the second adjustment process is completed, returning to Step S1 to obtain the next offset starting position.

[0020] Preferably, in this trajectory offset adjustment method, in Step S2, the first adjustment process is:

[0021] Step S21, adjust the YOZ inclination angle at the offset starting position;

[0022] Step S22, after the adjustment of the YOZ inclination angle is completed, gradually return the YOZ inclination angle to the original position, and at the termination position of the first adjustment process, make the YOZ inclination angle exactly return to the corresponding standard value to complete the first adjustment process.

[0023] Preferably, in this trajectory offset adjustment method, in step S3, the second adjustment process includes:

[0024] Step S31, after the execution of the first adjustment process, adjust the rotational speed of the stirring head and the welding speed at the starting position of the second adjustment process;

[0025] Step S32, after the adjustment of the rotational speed of the stirring head and the welding speed is completed, gradually restore the rotational speed of the stirring head and the welding speed, and at the termination position of the second adjustment process, make the rotational speed of the stirring head and the welding speed exactly restore to the corresponding standard values to complete the second adjustment process.

[0026] Preferably, in this trajectory offset adjustment method, a multi-dimensional force sensor is provided between the body of the welding robot and the flange connecting the main shaft of the stirring head, and the forces in the directions of the respective coordinate axes of the XYZ coordinate system of the welding robot are detected by the multi-dimensional force sensor;

[0027] Then, before executing step S1, first confirm the current offset state of the welding robot according to the detection results of the multi-dimensional force sensor;

[0028] When the welding robot has an offset and is in the first type of offset state not caused by the stacking points:

[0029] The position whose distance from the offset starting position is equal to the size of the shoulder of the stirring head is confirmed as the termination position of the first adjustment process.

[0030] Preferably, in this trajectory offset adjustment method, a multi-dimensional force sensor is provided between the body of the welding robot and the flange connecting the main shaft of the stirring head, and the forces in the directions of the respective coordinate axes of the XYZ coordinate system of the welding robot are detected by the multi-dimensional force sensor;

[0031] Then, before executing step S1, first confirm the current offset state of the welding robot according to the detection results of the multi-dimensional force sensor;

[0032] When the welding robot has an offset and is in the first type of offset state not caused by the stacking points:

[0033] After the first adjustment process is completed, the position where the detection result of the multi-dimensional force sensor meets the preset condition is used as the starting position of the second adjustment process, and

[0034] A position whose distance from the starting position of the second adjustment process is equal to five times the size of the shoulder of the stirring head is confirmed as the ending position of the second adjustment process.

[0035] Preferably, in this trajectory offset adjustment method, a multi-dimensional force sensor is arranged between the body of the welding robot and the flange connecting the main shaft of the stirring head, and the forces of the welding robot in the directions of each coordinate axis of the XYZ coordinate system are detected by the multi-dimensional force sensor;

[0036] Then, before performing the step S1, first confirm the current offset state of the welding robot according to the detection result of the multi-dimensional force sensor;

[0037] When the welding robot has an offset and is in the second type of offset state caused by the stacking welding point:

[0038] Confirm the ending position of the first adjustment process according to the detection result of the multi-dimensional force sensor:

[0039] If the detection result of the multi-dimensional force sensor always meets the preset detection condition between the offset starting position and a preset initial ending position, then the preset initial ending position is confirmed as the ending position of the first adjustment process;

[0040] If the detection result of the multi-dimensional force sensor does not meet the preset detection condition at any position between the offset starting position and a preset initial ending position, then the position where the preset detection condition is not met is confirmed as the ending position of the first adjustment process;

[0041] The distance between the offset starting position and the preset initial ending position is equal to 1.8 times the size of the shoulder of the stirring head.

[0042] Preferably, in this trajectory offset adjustment method, the preset detection condition is:

[0043] dF x +dF y ≤40;

[0044] Where:

[0045] dF x is used to represent the rate of change of the real-time force in the X-axis direction of the welding robot detected by the multi-dimensional force sensor;

[0046] dF yIt is used to represent the change rate of the real-time force in the Y-axis direction of the welding robot detected by the multi-dimensional force sensor.

[0047] Preferably, in this trajectory offset adjustment method, a multi-dimensional force sensor is arranged between the body of the welding robot and the flange of the main shaft connecting the stirring head, and the forces of the welding robot in the directions of each coordinate axis of the XYZ coordinate system are detected by the multi-dimensional force sensor;

[0048] Then, before performing the step S1, first confirm the current offset state of the welding robot according to the detection result of the multi-dimensional force sensor;

[0049] When the welding robot has an offset and is in the first type of offset state caused by the weld bead:

[0050] After the first adjustment process is completed, the position where the detection result of the multi-dimensional force sensor meets the preset condition is used as the starting position of the second adjustment process, and

[0051] The position whose distance from the starting position of the second adjustment process is equal to five times the size of the shoulder of the stirring head is confirmed as the termination position of the second adjustment process.

[0052] Preferably, in this trajectory offset adjustment method, when the detection result of the multi-dimensional force sensor meets the following preset conditions, the current position is used as the starting position of the second adjustment process:

[0053]

[0054] Wherein:

[0055] F x It is used to represent the real-time force in the X-axis direction of the welding robot detected by the multi-dimensional force sensor;

[0056] F y It is used to represent the real-time force in the Y-axis direction of the welding robot detected by the multi-dimensional force sensor;

[0057] F x0 It is used to represent the standard value of the force in the X-axis direction of the welding robot;

[0058] F y0 It is used to represent the standard value of the force in the Y-axis direction of the welding robot.

[0059] Preferably, in this trajectory offset adjustment method, the offset starting position is obtained in advance according to the weld bead shape, and the termination position of the first adjustment process, the starting position of the second adjustment process, and the termination position of the second adjustment process are set in advance according to the offset starting position;

[0060] For the case where the welding robot deviates not due to the stacking welding point:

[0061] The distance between the termination position of the first adjustment process and the deviation starting position is equal to the size of the shoulder of the stirring head;

[0062] The distance range between the starting position of the second adjustment process and the termination position of the first adjustment process is [1L, 1.5L], where L is used to represent the size of the shoulder of the stirring head;

[0063] The distance between the termination position of the second adjustment process and the starting position of the second adjustment process is equal to five times the size of the shoulder of the stirring head;

[0064] For the case where the welding robot deviates due to the stacking welding point:

[0065] Determine the deviation starting position as the position when the front end of the shoulder of the stirring head is flush with the end of the stacking welding point;

[0066] Determine the termination position of the first adjustment process as the position when the rear end of the shoulder of the stirring head is flush with the end of the stacking welding point;

[0067] The starting position of the second adjustment process coincides with the termination position of the first adjustment process;

[0068] The distance between the termination position of the second adjustment process and the starting position of the second adjustment process is equal to five times the size of the shoulder of the stirring head.

[0069] A welding control system is applied to a welding robot, and the welding robot is used for FSW operation; wherein, the above trajectory deviation adjustment method is applied to perform trajectory deviation adjustment during the welding process of the welding robot.

[0070] The beneficial effects of the above technical solutions are as follows: By adjusting the rotational speed and welding speed, the heat input during welding is adjusted in real time. By adjusting the YOZ inclination angle, the force distribution in the Y-axis direction and Z-axis direction is adjusted in real time, and the distribution of the heat input in the Y-axis direction is adjusted, thereby avoiding the possibility of trajectory deviation caused by the welding resistance exceeding the robot rigidity, improving the welding success rate of the FSW operation, and solving the problems of product yield and welding efficiency existing in the FSW operation platform of the serial robot. Brief Description of the Drawings

[0071] Figure 1-2 They are respectively the top views of the operation process of the stirring head of the robot in the prior art;

[0072] Figure 3It is a schematic diagram of the deviation of the welding trajectory caused by insufficient rigidity of the robot in the prior art;

[0073] Figure 4 It is a schematic diagram of the deviation of the welding trajectory affected by the pile welding point in the prior art;

[0074] Figure 5 It is a schematic structural diagram of a welding robot for FSW operation in the prior art;

[0075] Figures 6-8 It is a schematic diagram of the change state of the axial forces in the XYZ coordinate system during a typical FSW operation in the prior art;

[0076] Figure 9 It is a schematic diagram of the overall process of the trajectory deviation adjustment method in the preferred embodiment of the present invention;

[0077] Figure 10 It is a schematic diagram of the specific process of the first adjustment process in the preferred embodiment of the present invention;

[0078] Figure 11 It is a schematic diagram of the specific process of the second adjustment process in the preferred embodiment of the present invention;

[0079] Figure 12 It is a schematic structural diagram of adding a multi-dimensional force sensor to the welding robot in the preferred embodiment of the present invention.

[0080] Figures 13-15 It is a schematic structural diagram of the welding control system in the preferred embodiment of the present invention. Detailed implementation manners

[0081] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0082] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0083] Next, the present invention will be further described in conjunction with the accompanying drawings and specific embodiments, but it is not a limitation of the present invention.

[0084] In the preferred embodiment of the present invention, based on the above problems existing in the prior art, a trajectory deviation adjustment method is provided. This method is applied to a welding robot, and this welding robot is used for FSW operation. Its typical structure is as shown in Figure 5 as follows:

[0085] The welding robot includes a robot body 1 and a stirring head 2. The robot body 1 can be arranged on a robot platform 3. The stirring head 2 is connected to the robot body 1 through a main shaft 4, and the robot body 1 and the main shaft 4 of the stirring head are connected through a flange 5. A stirring pin 6 is also arranged below the stirring head 2.

[0086] Refer to Figure 1 , a XYZ coordinate system is constructed based on the weld position during welding, where the X-axis points to the welding advancing direction, and both the Y-axis and the Z-axis are perpendicular to the X-axis and perpendicular to the workpiece plane, where the Y-axis is perpendicular to the XOZ plane and the Z-axis is perpendicular to the XOY plane. As Figures 6-8 shown, in a typical FSW operation, the changing trends of the signals of the force outputs in the X, Y, and Z directions with time and the operation actions are presented.

[0087] Then the above trajectory offset adjustment method is specifically as Figure 9 shown in

[0088] Step S1, obtain the offset starting position where the welding robot generates an offset during welding;

[0089] Step S2, start executing a first adjustment process for adjusting the YOZ inclination angle between the Y-axis and the Z-axis of the welding robot at the offset starting position;

[0090] Step S3, after the first adjustment process is completed, start executing a second adjustment process for adjusting the rotation speed of the stirring head and the welding speed of the welding robot;

[0091] Step S4, after the second adjustment process is completed, return to Step S1 to obtain the next offset starting position.

[0092] Specifically, different from the traditional FSW control method, the adjustment parameters in this embodiment include the rotation speed of the stirring head, the welding speed (linear speed in the advancing direction of the stirring head), and the YOZ inclination angle of the welding robot. Moreover, the trajectory offset adjustment process is divided into two adjustment processes before and after: in the first adjustment process, the YOZ inclination angle is adjusted; after the first adjustment process is completed, the second adjustment process is started to adjust the rotation speed of the stirring head and the welding speed.

[0093] The above trajectory adjustment method is based on the following basic logic:

[0094] As described above, during the welding process, the prerequisite for the welding robot to maintain accurate trajectory is that the rigidity of the robot is sufficient to resist the welding resistance received by the stirring head.

[0095] During the FSW operation, the rigidity of the welding robot in three directions is different, usually Z > X > Y, which is determined by the structural characteristics and control logic of the serial robot itself.

[0096] The welding resistance is positively correlated with the strength of the material at the welding temperature, and the welding temperature is determined by the heat input per unit time. The heat during the FSW operation comes from the heat generated by the rotational friction of the stirring head. Therefore, the rotational speed of the stirring head and the welding speed determine the heat input during the FSW operation, and thus determine the welding resistance.

[0097] Therefore, based on the above basic logic, in the technical solution of the present application, the heat input of welding is adjusted in real time by controlling the rotational speed of the stirring head and the welding speed. By adjusting the YOZ inclination angle, the force distribution in the Y and Z directions is adjusted, and the distribution of the heat input in the Y direction is adjusted, so that the welding trajectory of the robot can be corrected.

[0098] In a preferred embodiment of the present invention, in the above step S2, the first adjustment process is as Figure 10 shown, specifically:

[0099] Step S21, adjust the YOZ inclination angle at the offset starting position;

[0100] Step S22, after the adjustment of the YOZ inclination angle is completed, gradually return the YOZ inclination angle to the correct position, and at the end position of the first adjustment process, the YOZ inclination angle just returns to the corresponding standard value to complete the first adjustment process.

[0101] In a preferred embodiment of the present invention, in the above step S3, the second adjustment process is as Figure 11 shown, specifically:

[0102] Step S31, after the execution of the first adjustment process, adjust the rotational speed of the stirring head and the welding speed at the starting position of the second adjustment process;

[0103] Step S32, after the adjustment of the rotational speed of the stirring head and the welding speed is completed, gradually restore the rotational speed of the stirring head and the welding speed, and at the end position of the second adjustment process, the rotational speed of the stirring head and the welding speed respectively just return to the corresponding standard values to complete the second adjustment process.

[0104] Then in a preferred embodiment of the present invention, based on Figures 9-11 the trajectory offset adjustment process in, multiple different embodiments are used hereinafter to describe the specific control logic therein:

[0105] Example 1:

[0106] This embodiment is directed to a typical trajectory offset situation, that is, as Figure 3The robot trajectory deviation caused by the condition of the weld seam itself shown in the figure is hereinafter referred to as deviation condition one for convenience of description.

[0107] In deviation condition one, the state of the robot trajectory deviation reflected in the force monitoring information is: F x (the force received in the X-axis direction) and F y (the force received in the Y-axis direction) rise rapidly, and the rapid rise of F y actually results from the instability in the Y-axis direction caused by the rapid rise of F x .

[0108] The corresponding adjustment scheme can be:

[0109] By increasing the heat input to cause temperature rise, reduce the flow resistance of the material, and thus reduce the welding resistance generated on the stirring head.

[0110] By increasing the rotation speed and welding speed to reduce the influence brought by the rapid rise of F y .

[0111] On the basis of increasing the heat input, increase the inclination angle in the direction of F y . The inclination angle in the Y-axis direction can transfer part of F y to F z (the force received in the Z-axis direction). Since the rigidity of the robot in the Z-axis direction is relatively good, transferring part of the force to the Z-axis can reduce the tendency of instability in the Y-axis direction. The increase in the inclination angle in the Y-axis direction can also make the equivalent heat source center of the robot move slightly towards the positive direction of the Y-axis, which helps the welding robot to maintain stability in the Z-axis direction.

[0112] Therefore, through the above adjustment scheme, while reducing the welding resistance of the material, use the relatively high rigidity in the Z-axis direction to make up for the defects in the Y-axis direction, thereby greatly reducing the order of magnitude of the trajectory deviation δ value and avoiding trajectory deviation.

[0113] Specifically, for the above deviation condition one, in this embodiment, as Figure 12 shown in the figure, a multi-dimensional force sensor 7 is arranged between the main body 1 of the welding robot and the flange 5 connecting the spindle 4 of the stirring head, and the multi-dimensional force sensor 7 is used to detect the forces of the welding robot in the directions of each coordinate axis of the XYZ coordinate system.

[0114] Before executing step S1, first confirm the current deviation state of the welding robot according to the detection results of the multi-dimensional force sensor;

[0115] When the welding robot has a deviation and is in the first type of deviation state (deviation condition one) not caused by the welding point:

[0116] For the first adjustment process:

[0117] The position where the distance from the offset starting position is equal to the size of the shoulder of the stirring head is confirmed as the termination position of the first adjustment process.

[0118] For the second adjustment process:

[0119] After the first adjustment process is completed, the position where the detection result of the multi-dimensional force sensor meets the preset conditions is used as the starting position of the second adjustment process, and

[0120] The position where the distance from the starting position of the second adjustment process is equal to five times the size of the shoulder of the stirring head is confirmed as the termination position of the second adjustment process.

[0121] Specifically, the force monitoring conditions for confirming the occurrence of the first offset situation can be preset. For example, based on a large number of experiments and data collation and statistics, in this embodiment, the following conditions are determined as the force monitoring conditions for the occurrence of the first offset situation:

[0122]

[0123] Among them:

[0124] dF x Used to represent the rate of change of the real-time force of the welding robot detected by the multi-dimensional force sensor in the X-axis direction;

[0125] dF y Used to represent the rate of change of the real-time force of the welding robot detected by the multi-dimensional force sensor in the Y-axis direction;

[0126] dF z Used to represent the rate of change of the real-time force of the welding robot detected by the multi-dimensional force sensor in the Z-axis direction.

[0127] The so-called rate of change of force is defined as: the ratio of the change in welding resistance to 1% of the stable welding resistance within a unit time (0.1 second). For example, if Fx = 1000N and its change amount within 0.1 second is 100N, then the rate of change of force dFx at this time is 10.

[0128] When the multi-dimensional force sensor detects that the current real-time force output distribution meets the above conditions, it is determined that the robot has a trajectory offset at this time, and this trajectory offset is the first offset situation.

[0129] Furthermore, when the first offset situation occurs, it is necessary to determine the starting position of the first adjustment process (hereinafter simply referred to as point A), the termination position of the first adjustment process (hereinafter simply referred to as point B), the starting position of the second adjustment process (hereinafter simply referred to as point C), and the termination position of the second adjustment process (hereinafter simply referred to as point D), where:

[0130] Point A is fixed as the position where the offset occurs, i.e., the starting position of the offset.

[0131] Point B is fixed as the position at a distance L from Point A. This L is the size of the shoulder of the stirring head. It should be noted that the "distance" here refers to the weld path, that is, the length of the weld path between Point A and Point B is L, rather than the straight-line distance between Point A and Point B. The "distance" referred to in the following text all refers to the length traveled along the weld path, and will not be elaborated one by one.

[0132] Point C is a certain point after Point B. That is, starting from Point B, the multi-dimensional force sensor monitors whether a certain preset condition is met, and the point that meets the preset condition is taken as Point C. The preset condition can be set based on a large number of experiments and data collation and statistics as:

[0133]

[0134] Among them,

[0135] F x0 is used to represent the standard value of the force of the welding robot in the X-axis direction;

[0136] F y0 is used to represent the standard value of the force of the welding robot in the Y-axis direction.

[0137] Specifically, the above F z0 and F z0 can be obtained through a pre-measurement process. The standard value of the force of the welding robot in the Z-axis direction F z0 , the standard value R0 of the rotation speed of the stirring head, the standard value S0 of the welding speed, and the standard value αy0 of the YOZ inclination angle can also be obtained in advance during this measurement process. Further, the standard value P0 of the downward pressure of the stirring head and the standard value αx0 of the XOZ inclination angle can also be obtained, etc.

[0138] Of course, in this embodiment, after obtaining the standard values F x0 , F y0 and F z0 of the forces in the XYZ directions, the standard values dF x0 , dF y0 and dF z0 of the force change rates can be obtained.

[0139] The above-mentioned preliminary measurement process is specifically as follows: adopting the traditional FSW control method described above, when the welding robot performs long-distance welding of more than 1.5 meters, the average value of various parameter values obtained within the stable welding section. The so-called stable welding section means that the welding resistance received by the welding robot is stable and less than the rigidity of the welding robot, so that the trajectory of the welding robot does not deviate and is consistent with the standard trajectory.

[0140] In addition, it should be noted that during the process of the pre-configured welding robot performing FSW operations according to the predetermined trajectory, various parameters of the welding robot can be replaced by the above-mentioned standard values obtained through preliminary measurement. That is, it can be considered that when the welding robot is performing FSW operations normally, its various parameters are the above-mentioned standard values.

[0141] It should be noted that according to the detection results of the multi-dimensional force sensor, point C may coincide with point B, that is, the starting position of the second adjustment process may coincide with the ending position of the first adjustment position, and the adjustment of the rotation speed and welding speed of the stirring head is directly started from point B.

[0142] Then in the above-mentioned first adjustment process:

[0143] In the above step S21, the method of adjusting the YOZ inclination angle at the starting position of the deviation is: adjusting the YOZ inclination angle from αy0 = 0° to αy = (0.8 + j)°. Where:

[0144] j = dF y *0.0025; (3)

[0145] The process of adjusting the YOZ inclination angle is a gradual process, that is, gradually adjusting from αy0 to αy. Then after the adjustment of the YOZ inclination angle is completed, that is, after the YOZ inclination angle has been adjusted to αy, it indicates that the correction of the YOZ inclination angle has met the requirements. At this time, the operation of gradually returning the YOZ inclination angle to the original state is immediately started, that is, adjusting the YOZ inclination angle from αy back to αy0.

[0146] Furthermore, the process of gradually returning the YOZ inclination angle to the original state starts from when the YOZ inclination angle is adjusted to αy and ends at point B. That is, at point B, the YOZ inclination angle is exactly returned to αy0 = 0°, and at this time the first adjustment process is completed.

[0147] In the above-mentioned first adjustment process, the positive value of αy0 means that the stirring head is tilted towards the positive direction of the Y axis in the ZOY plane with the welding point as the center.

[0148] In the above-mentioned second adjustment process:

[0149] First, start the second adjustment process at point C, adjust the rotation speed of the stirring head from the standard value R0 to R = h * R0, and adjust the welding speed of the stirring head from the standard value S0 to S = i * S0, where:

[0150]

[0151] Similarly, the above adjustment process is a gradual process. After the rotation speed of the stirring head is adjusted from the standard value R0 to R, immediately start gradually restoring the rotation speed of the stirring head to the standard value R0. And after the welding speed of the stirring head is adjusted from the standard value S0 to S, immediately start gradually restoring the welding speed of the stirring head to the standard value S0. The above restoration process ends at point D, the termination position of the first adjustment process. The distance between point D and point C is 5L. When reaching point D, the rotation speed of the stirring head exactly returns to R0, and the welding speed exactly returns to S0. In other words, when the welding robot reaches point D, the second adjustment process is completed, then the trajectory offset adjustment process for this section is completed, and the system continues to perform FSW operations according to the established welding parameters until the next offset starting position appears, and then repeats the above steps S1 - S4.

[0152] In the technical solution of the present invention, the concept of the size of the shoulder of the stirring head is introduced to relatively lengthen the first adjustment process and the second adjustment process, and the lengthening degree conforms to the situation of different stirring heads themselves, so that the adjustment of parameter values in the two adjustment processes is appropriately gentle, reducing the impact on the equipment and FSW operations caused by sudden rises and falls of parameters. It will not be elaborated further below.

[0153] Example 2:

[0154] This embodiment is directed to the situation of robot trajectory offset caused by Figure 4 as shown in the figure. For the convenience of description below, this situation is called offset situation two.

[0155] Compared with offset situation one, in offset situation two, due to the existence of additional materials, the situation is more complex. Theoretically, when encountering a piled weld, the forces F x 、F y and F z on the XYZ three axes of the welding robot will rise rapidly at the same time, and the rising amplitude F z >F x >F y . If the rigidity of the robot itself can ensure that the offset of the stirring head in the Y-axis direction is within a certain range, then there may be a plateau area for the forces in the three directions, and then decrease, and finally return to the level before passing the piled weld. However, in the actual welding process, as Figure 4As shown in [Figure 0], due to the insufficient rigidity of the welding robot, when passing through the stacking welding point, the stirring head often tends to be pushed in the positive Y-axis direction. In this case, the rising amplitude of F z will be less than that in the first embodiment, but the rising amplitude of F y will be much greater than that in the first embodiment, and there will be a phenomenon of sudden drop and sudden rise of F x and F y in the second half of passing through the stacking welding point. Welding under such welding conditions, the welding trajectory completely fails to cover the target weld seam, which is unacceptable in terms of quality requirements.

[0156] Therefore, when it is detected that F x 、F y and F z rise rapidly at the same time, the rotation speed of the stirring head should be increased and the welding speed of the stirring head should be decreased, so as to achieve the purpose of adjusting the heat input and further adjusting the welding resistance. In this embodiment, the adjustment range of the heat input is higher than that in the first embodiment.

[0157] In addition, in this embodiment, the selection of the YOZ inclination angle is also different from that in the first embodiment:

[0158] Firstly, the starting point for introducing the YOZ inclination angle adjustment is different. In the working condition of the first embodiment, the purpose of adjusting the YOZ inclination angle is to adjust the distribution of the welding resistance in different directions. In this embodiment, due to the existence of the stacking welding point, the stirring head needs to stir more materials per unit time, and the welding resistance in the Z-axis direction is much greater than that in the normal welding state, and it is difficult to share the welding resistance in the Y-axis direction. Therefore, in this embodiment, the YOZ inclination angle is adjusted by a method of adjusting towards the negative Y-axis direction. At this time, due to the existence of the relatively high-hardness redundant materials at the stacking welding point, with an appropriate heat input, it just makes the rigid resistance of the welding robot reach balance in the Z-axis direction, and in this state, the equivalent heat source center also moves to the negative Y-axis direction, which is beneficial for the stirring head to plunge along the Z-axis direction and extrude the redundant materials towards the positive Y-axis direction, so as to ensure that the center position of the actual tool center point (TCP) remains unchanged.

[0159] Secondly, as the welding continues, when it is detected that the force in the Z-axis direction decreases, it means that the stacking welding point area is about to be left. At this time, the inclination angle in the negative Y-axis direction needs to be gradually reduced to 0°, and then the rotation speed is reduced and the welding speed is increased, and the welding operation in the stacking welding point area can be completed.

[0160] In this embodiment, when facing the bead weld with excess material, the reason for using the lateral inclination instead of increasing the original inclination of the XOZ plane is as follows: on the one hand, an excessive inclination in the negative X-axis direction will damage the surface state of the weld seam, resulting in an excessive reduction in the thickness of the weld seam area. On the other hand, increasing the XOZ inclination makes it difficult to form a force balance in the Y-axis direction, and there is a certain probability of instability, thus deviating from the weld seam. Therefore, in this embodiment, the YOZ inclination is selected for adjustment to avoid affecting the welding quality.

[0161] It should be noted that this embodiment only deals with the bead welds with the height of excess material below 3 mm. If the bead weld is too high, it cannot be processed.

[0162] Then in this embodiment, the composition of the welding robot is still as Figure 13 shown, that is, a multi-dimensional force sensor 7 is arranged between the body 1 of the robot and the flange 5 connecting the spindle 4 of the stirring head.

[0163] Before performing step S1, first confirm the current offset state of the welding robot according to the detection result of the multi-dimensional force sensor;

[0164] When the welding robot has an offset and is in the second type of offset state (offset situation two) caused by the bead weld:

[0165] For the first adjustment process:

[0166] Confirm the termination position of the first adjustment process according to the detection result of the multi-dimensional force sensor:

[0167] If the detection result of the multi-dimensional force sensor always meets the preset detection conditions from the offset starting position to a preset initial termination position, then the preset initial termination position is confirmed as the termination position of the first adjustment process;

[0168] If the detection result of the multi-dimensional force sensor does not meet the preset detection conditions at any position from the offset starting position to a preset initial termination position, then the position where the preset detection conditions are not met is confirmed as the termination position of the first adjustment process;

[0169] The distance between the offset starting position and the preset initial termination position is equal to 1.8 times the size of the shoulder of the stirring head.

[0170] For the second adjustment process:

[0171] After the first adjustment process is completed, the position where the detection result of the multi-dimensional force sensor meets the preset conditions is used as the starting position of the second adjustment process, and

[0172] The position where the distance from the starting position of the second adjustment process is equal to five times the size of the shoulder of the stirring head is confirmed as the termination position of the second adjustment process.

[0173] Specifically, the force monitoring conditions for confirming the occurrence of offset situation 2 are also preset in advance. For example, based on a large number of experiments and data collation and statistics, in this embodiment, the following conditions are determined as the force monitoring conditions for the occurrence of offset situation 2:

[0174]

[0175] When the multi-dimensional force sensor detects that the current real-time force output distribution meets the above conditions, it is determined that the robot has a trajectory offset at this time, and this trajectory offset is offset situation 2.

[0176] Furthermore, when offset situation 2 occurs, it is necessary to determine point A and point B of the first adjustment process, and determine point C and point D of the second adjustment process, where:

[0177] Point A is also fixed at the position where the offset occurs, that is, the starting position of the offset.

[0178] For point B:

[0179] First, determine an initial termination position, point B0, which is fixed at a distance of 1.8L from point A.

[0180] Subsequently, during the process of adjusting and returning the YOZ inclination angle from point A to point B, continuously monitor the force output result, and determine whether it is necessary to set point B before point B0 by judging whether the force output result meets the preset conditions, that is, judge whether it is necessary to terminate the first adjustment process in advance.

[0181] Based on a large number of experiments and data collation and statistics, the above preset conditions are set as:

[0182] dF x +dF y ≤40; (6)

[0183] Then in this embodiment:

[0184] If before reaching point B0, the continuously monitored results always meet the above preset conditions, it can be considered that there is no need to terminate the first adjustment process in advance, that is, the termination position of the first adjustment process, point B, is point B0.

[0185] If before reaching point B0, the continuously monitored results indicate that there is a certain position where the rate of change of force does not meet the above preset conditions, that is, dF x +dF y >40, it indicates that it is necessary to terminate the first adjustment process in advance, that is, take this point as point B, and immediately return the YOZ inclination angle to 0 at point B to complete the first adjustment process.

[0186] In this embodiment, after the first adjustment process is completed, that is, starting from point B, the multi-dimensional force sensor monitors whether a certain preset condition is met, and takes the point that meets the preset condition as point C. The preset condition can also refer to formula (2) in Embodiment 1, which will not be elaborated here.

[0187] Similarly, according to the detection result of the multi-dimensional force sensor, point C may coincide with point B, that is, the starting position of the second adjustment process may coincide with the ending position of the first adjustment position, and the rotation speed and welding speed of the stirring head are directly adjusted starting from point B.

[0188] Then in the above first adjustment process:

[0189] In the above step S21, the method of adjusting the YOZ inclination angle at the offset starting position is: adjusting the YOZ inclination angle from αy0 = 0° to αy = -(1.1 + j)°. Where:

[0190] j = dF y *0.0015; (7)

[0191] The process of adjusting the YOZ inclination angle is a gradual process, that is, gradually adjusting from αy0 to αy. After the adjustment of the YOZ inclination angle is completed, that is, after the YOZ inclination angle has been adjusted to αy, it indicates that the correction of the YOZ inclination angle has met the requirements. At this time, the operation of gradually returning the YOZ inclination angle to the original state is immediately started, that is, adjusting the YOZ inclination angle from αy back to αy0.

[0192] Further, the process of gradually returning the YOZ inclination angle to the original state starts from when the YOZ inclination angle is adjusted to αy and ends at point B. That is, at point B (at this time, point B is point B0), the YOZ inclination angle is exactly returned to αy0 = 0°, and at this time, the first adjustment process is completed. Or

[0193] Gradually return the YOZ inclination angle to the original state, and directly return the YOZ inclination angle to αy0 = 0° at point B (at this time, point B is before point B0), and at this time, the first adjustment process is completed.

[0194] In the above first adjustment process, the positive value of αy0 means that the stirring head is tilted towards the positive direction of the Y-axis in the ZOY plane with the welding point as the center.

[0195] In the above second adjustment process:

[0196] First, start the second adjustment process at point C, adjust the rotation speed of the stirring head from the standard value R0 to R = h * R0, and adjust the welding speed of the stirring head from the standard value S0 to S = i * S0. The corresponding parameter calculation method can refer to formula (4) in Embodiment 1.

[0197] Similarly, the above adjustment process is a gradual process. After the rotational speed of the stirring head is adjusted from the standard value R0 to R, the rotational speed of the stirring head is immediately started to be gradually restored to the standard value R0. And after the welding speed of the stirring head is adjusted from the standard value S0 to S, the welding speed of the stirring head is immediately started to be gradually restored to the standard value S0. The above restoration process ends at the termination position D of the first adjustment process. The distance between point D and point C is 5L. When reaching point D, the rotational speed of the stirring head exactly returns to R0, and the welding speed exactly returns to S0. In other words, when the welding robot reaches point D, the second adjustment process is completed, then the trajectory offset adjustment process for this section is completed, and the system continues to perform FSW operations according to the established welding parameters until the next offset starting position appears, and then repeats the above steps S1 - S4.

[0198] Example 3:

[0199] The basis of the above two embodiments is that a multi - dimensional force sensor is installed on the welding robot, and the trajectory offset adjustment is implemented according to the detection results of the multi - dimensional force sensor.

[0200] Correspondingly, for the situation where the multi - dimensional force sensor is not installed on the welding robot or the multi - dimensional force sensor is turned off (that is, the detection results of the multi - dimensional force sensor cannot be obtained), the technical solution of the present invention can also be applied. Specifically, it can be done according to the method of this embodiment:

[0201] In this embodiment, the offset situation one and offset situation two are also distinguished, but the offset starting position and the end positions (starting position & termination position) of the two adjustment processes are no longer determined according to the detection results of the multi - dimensional force sensor. Correspondingly, in this embodiment, a pre - setting method is used to determine the end positions of the first adjustment process and the second adjustment process. Specifically:

[0202] A welding robot equipped with a multi - dimensional force sensor is pre - used to determine the offset starting position according to the predetermined weld trajectory / build - up welding point on the workpiece to be welded. That is, in this embodiment, the offset starting position has been pre - determined.

[0203] Then for offset situation one:

[0204] Point A is fixed as the offset starting position.

[0205] Point B is still set to be at a distance of L from point A.

[0206] Point C can be selected within the range of [1L, 1.5L] after point B and at a distance of [1L, 1.5L] from point B, based on a large number of experiments and data collation and statistics.

[0207] Point D is still set to be at a distance of 5L from point C.

[0208] For the adjustment method of the first offset situation, refer to Embodiment 1. That is, except for the different selection of the end positions of the first adjustment process and the second adjustment process, the adjustment methods of the YOZ inclination angle, the rotation speed of the stirring head, and the welding speed in the first offset situation are exactly the same as those in Embodiment 1.

[0209] Regarding the second offset situation:

[0210] Point A is the position when the shoulder of the stirring head touches the surfacing weld point, specifically the position when the front end of the shoulder is flush with the end of the surfacing weld point.

[0211] Point B is the position when the rear end of the shoulder of the stirring head is flush with the end of the surfacing weld point.

[0212] Point C coincides with Point B.

[0213] Point D is still set to be 5L away from Point C.

[0214] For the adjustment method of the second offset situation, refer to Embodiment 2. That is, except for the different selection of the end positions of the first adjustment process and the second adjustment process, the adjustment methods of the YOZ inclination angle, the rotation speed of the stirring head, and the welding speed in the second offset situation are exactly the same as those in Embodiment 1.

[0215] In addition, in actual welding production, there is also a situation where part or all of the surplus height of the surfacing weld point is ground off. However, since there is still a hardness difference between the metal under the surfacing weld point and the surrounding base metal area, although there is no surfacing weld point on the surface, it will actually still cause a greater weld offset compared to Embodiment 1. Therefore, in this embodiment, for this situation:

[0216] If the hardness of the remaining surfacing area is more than 30% higher than that of the base metal, then it is still regarded as the situation where there is a surfacing weld point, that is, regarded as the second offset situation.

[0217] If the hardness of the remaining surfacing area is less than 20% higher than that of the base metal, then it is regarded as the first offset situation.

[0218] If the difference in hardness between the remaining surfacing area and the base metal is between 20% and 30%, then it is regarded as the first offset situation or the second offset situation depending on the actual experimental effect.

[0219] In a preferred embodiment of the present invention, a welding control system is further provided. The welding control system is applied to a welding robot, and the welding robot is used for FSW operations. Among them, the welding control system applies the trajectory offset adjustment method described above to adjust the trajectory offset during the FSW operation of the welding robot.

[0220] Construct an XYZ coordinate system on the welding robot, where the X-axis points in the forward direction of the welding robot, the Y-axis points in the lateral direction of the welding robot, and the Z-axis is perpendicular to the XOY plane and points upward above the welding robot.

[0221] The welding control system is specifically as Figure 13 shown, and includes:

[0222] An offset detection unit 131 for obtaining the offset starting position where the welding robot generates an offset during welding;

[0223] A first adjustment unit 132, connected to the offset detection unit 131, starts to execute a first adjustment process for adjusting the YOZ inclination angle between the Y-axis and the Z-axis of the welding robot at the offset starting position;

[0224] A second adjustment unit 133, connected to the first adjustment unit 13, starts to execute a second adjustment process for adjusting the rotation speed of the stirring head and the welding speed of the welding robot after the first adjustment process is completed.

[0225] Furthermore, as Figure 14 shown, the above-mentioned first adjustment unit 132 specifically includes:

[0226] A first adjustment module 1321 for adjusting the YOZ inclination angle of the welding robot at the offset starting position;

[0227] A second adjustment module 1322, connected to the first adjustment module 1321, after the YOZ inclination angle of the welding robot is adjusted, the second adjustment module 1412 gradually returns the YOZ inclination angle to the normal and makes the YOZ inclination angle exactly return to the corresponding standard value at the termination position of the first adjustment process to complete the first adjustment process.

[0228] As Figure 15 shown, the second adjustment unit 133 specifically includes:

[0229] A third adjustment module 1331 for adjusting the rotation speed of the stirring head and the welding speed at the starting position of the second adjustment process after the first adjustment process is completed;

[0230] A fourth adjustment module 1332, connected to the third adjustment module 1331, after the rotation speed of the stirring head and the welding speed are adjusted, the fourth adjustment module 1332 gradually restores the rotation speed of the stirring head and the welding speed and makes the rotation speed of the stirring head and the welding speed exactly restore to the corresponding standard values at the termination position of the second adjustment process to complete the second adjustment process.

[0231] The above are only the preferred embodiments of the present invention, and do not limit the implementation manners and protection scope of the present invention. For those skilled in the art, it should be realized that all the equivalent replacements and obvious changes made by using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A trajectory offset adjustment method, applied to a welding robot, wherein the welding robot is used for FSW operation; characterized in that: An XYZ coordinate system is constructed based on the weld position during welding, where the X axis points to the welding forward direction, the Y axis and the Z axis are both perpendicular to the X axis and the surface of the workpiece to be welded, the Y axis is perpendicular to the XOZ plane, and the Z axis is perpendicular to the XOY plane; The trajectory offset adjustment method comprises: Step S1, obtaining a starting position of a deviation of the welding robot during welding; Step S2, starting to perform a first adjustment process of adjusting the YOZ inclination angle between the Y axis and the Z axis of the welding robot at the offset starting position; Step S3, after the first adjustment process is completed, starting to execute a second adjustment process for adjusting the stirring head rotation speed and welding speed of the welding robot; Step S4, after the second adjustment process is completed, return to step S1 to obtain the next offset starting position.

2. The trajectory deviation adjustment method according to claim 1, characterized in that: In step S2, the first adjustment process is: Step S21, adjusting the YOZ inclination angle at the offset starting position; Step S22, after the YOZ inclination angle is adjusted, the YOZ inclination angle is gradually corrected, and at the end position of the first adjustment process, the YOZ inclination angle is just corrected to the corresponding standard value to complete the first adjustment process.

3. The trajectory deviation adjustment method according to claim 1, characterized in that: In step S3, the second adjustment process includes: Step S31, after the first adjustment process is completed, adjusting the stirring head rotation speed and the welding speed at the starting position of the second adjustment process; Step S32, after the rotation speed and welding speed of the stirring head are adjusted, the rotation speed and welding speed of the stirring head are gradually restored, and at the end position of the second adjustment process, the rotation speed and welding speed of the stirring head are restored to the corresponding standard values ​​respectively, so as to complete the second adjustment process.

4. The trajectory deviation adjustment method according to claim 2, characterized in that: A multi-dimensional force sensor is arranged between the body of the welding robot and the flange of the main shaft connected to the stirring head, and the force of the welding robot along each coordinate axis direction of the XYZ coordinate system is detected by the multi-dimensional force sensor; Before executing step S1, firstly confirm the current offset state of the welding robot according to the detection result of the multi-dimensional force sensor; When the welding robot is offset and is in a first type of offset state that is not caused by the cladding point: A position whose distance from the offset starting position is equal to the size of the shaft shoulder of the stirring head is determined as the end position of the first adjustment process.

5. The trajectory deviation adjustment method according to claim 3, characterized in that: A multi-dimensional force sensor is arranged between the body of the welding robot and the flange of the main shaft connected to the stirring head, and the force of the welding robot along each coordinate axis direction of the XYZ coordinate system is detected by the multi-dimensional force sensor; Before executing step S1, firstly confirm the current offset state of the welding robot according to the detection result of the multi-dimensional force sensor; When the welding robot is offset and is in a first type of offset state that is not caused by the cladding point: After the first adjustment process is completed, the position where the detection result of the multi-dimensional force sensor meets the preset condition is used as the starting position of the second adjustment process, and A position whose distance from the starting position of the second adjustment process is equal to five times the size of the shoulder of the stirring head is determined as the ending position of the second adjustment process.

6. The trajectory deviation adjustment method according to claim 2, characterized in that: A multi-dimensional force sensor is arranged between the body of the welding robot and the flange of the main shaft connected to the stirring head, and the force of the welding robot along each coordinate axis direction of the XYZ coordinate system is detected by the multi-dimensional force sensor; Before executing step S1, firstly confirm the current offset state of the welding robot according to the detection result of the multi-dimensional force sensor; When the welding robot is deviated and in the second type of deviated state caused by the cladding point: Confirming the termination position of the first adjustment process according to the detection result of the multi-dimensional force sensor: If the detection result of the multi-dimensional force sensor always satisfies the preset detection condition between the offset starting position and a preset initial end position, the preset initial end position is confirmed as the end position of the first adjustment process; If the detection result of the multi-dimensional force sensor does not meet the preset detection condition at any position between the offset starting position and a preset initial end position, the position where the preset detection condition is not met is confirmed as the end position of the first adjustment process; The distance between the offset starting position and the preset initial ending position is equal to 1.8 times the size of the shoulder of the stirring head.

7. The trajectory deviation adjustment method according to claim 6, characterized in that: The preset detection conditions are: dF x +dF y ≤40; in: dF x Used to represent the real-time rate of change of the force of the welding robot along the X-axis direction detected by the multi-dimensional force sensor; dF y Used to represent the real-time rate of change of the force of the welding robot along the Y-axis direction detected by the multi-dimensional force sensor.

8. The trajectory deviation adjustment method according to claim 3, characterized in that: A multi-dimensional force sensor is arranged between the body of the welding robot and the flange of the main shaft connected to the stirring head, and the force of the welding robot along each coordinate axis direction of the XYZ coordinate system is detected by the multi-dimensional force sensor; Before executing step S1, firstly confirm the current offset state of the welding robot according to the detection result of the multi-dimensional force sensor; When the welding robot is offset and in a first type of offset state caused by the cladding point: After the first adjustment process is completed, the position where the detection result of the multi-dimensional force sensor meets the preset condition is used as the starting position of the second adjustment process, and A position whose distance from the starting position of the second adjustment process is equal to five times the size of the shoulder of the stirring head is determined as the ending position of the second adjustment process.

9. The trajectory deviation adjustment method according to claim 5 or 8, characterized in that: When the detection result of the multi-dimensional force sensor meets the following preset conditions, the current position is used as the starting position of the second adjustment process: in: F x Used to represent the real-time force of the welding robot along the X-axis direction detected by the multi-dimensional force sensor; F y Used to represent the real-time force of the welding robot along the Y-axis direction detected by the multi-dimensional force sensor; F x0 Used to represent the standard value of the force of the welding robot along the X-axis direction; F y0 Used to represent the standard value of the force of the welding robot along the Y-axis direction.

10. The trajectory deviation adjustment method according to claim 1, characterized in that: Pre-obtaining the offset starting position according to the weld morphology, and pre-setting the end position of the first adjustment process, the start position of the second adjustment process, and the end position of the second adjustment process according to the offset starting position; Regarding the case where the welding robot is offset due to reasons other than the cladding point: The distance between the end position of the first adjustment process and the starting position of the offset is equal to the size of the shoulder of the stirring head; The distance range between the starting position of the second adjustment process and the ending position of the first adjustment process is [1L, 1.5L], where L is used to represent the size of the shoulder of the stirring head; The distance between the end position of the second adjustment process and the start position of the second adjustment process is equal to five times the size of the shoulder of the stirring head; Regarding the situation where the welding robot is offset due to the cladding point: Determine the offset starting position as the position where the front end of the shoulder of the stirring head is flush with the end of the surfacing point; Determine the end position of the first adjustment process as the position where the rear end of the shaft shoulder of the stirring head is flush with the end of the surfacing point; The starting position of the second adjustment process coincides with the ending position of the first adjustment process; The distance between the end position of the second adjustment process and the start position of the second adjustment process is equal to five times the size of the shoulder of the stirring head.

11. A welding control system, applied to a welding robot, wherein the welding robot is used for performing FSW operations; characterized in that: The trajectory offset adjustment method as described in any one of claims 1 to 10 is applied to perform trajectory offset adjustment during the welding process of the welding robot.

Images