CN114769988B - Welding control method, system, welding equipment and storage medium - Google Patents

Abstract

The application discloses a welding control method, a welding control system, welding equipment and a storage medium, and belongs to the technical field of vision tracking algorithm technology for improving welding precision and efficiency. The welding control method comprises the following steps: controlling the welding gun to move to an initial position, and determining a welding seam starting point of the workpiece by utilizing a visual sensor; controlling the welding gun to move towards the starting point of the welding seam, and acquiring welding seam data by utilizing a visual sensor; judging whether weld end points are contained in the weld data acquired by the visual sensor; if yes, generating a welding track from a welding seam starting point to a welding seam ending point according to the welding seam data, and controlling a welding gun to weld the workpiece according to the welding track; if not, generating a trend space straight line according to the actual motion data of the welding gun, calculating a corrected coordinate point, and controlling the welding gun to move towards the corrected coordinate point until the welding seam data acquired by the visual sensor contains a welding seam termination point, so that welding precision and efficiency are improved.

Description

Welding control method, system, welding equipment and storage medium

Technical Field

The application relates to the technical field of visual tracking algorithms, in particular to a welding control method, a welding control system, welding equipment and a storage medium.

Background

With the development of manufacturing industry, a great deal of automation and intelligent equipment is needed to replace manual operation in many industries so as to improve the production efficiency and the operation quality. In the welding production operation of the reworking industry, automatic welding is mostly adopted. However, for the welding of the medium plate, there are problems of workpiece processing errors, position errors after clamping, thermal deformation of the workpiece during welding, deviation of clamping positions during welding operation and the like, and the factors may cause the change of welding tracks during the welding process, so that the welding operation tracks deviate from actual welding seams, and the welding quality is directly affected.

In order to ensure the quality and the efficiency of welding of a welding seam, the related technology mainly adopts a welding seam automatic tracking technology to carry out automatic welding, and the existing welding seam automatic tracking mode is mainly based on the fact that a preposed optical vision sensor is arranged on a welding gun tool of a welding robot, the position of a welding seam characteristic point is detected and calculated in real time through the sensor, and the robot is controlled to carry out automatic tracking welding according to the position of the characteristic point. However, when the welding seam is suddenly changed in the mode, the convergence of the tracking track is poor, and the welding accuracy is low.

Therefore, how to improve welding accuracy and efficiency is a technical problem that a person skilled in the art needs to solve at present.

Disclosure of Invention

The application aims to provide a welding control method, a welding control system, a storage medium and welding equipment, which can improve welding precision and efficiency.

In order to solve the technical problems, the present application provides a welding control method applied to a welding device, wherein a welding gun and a vision sensor are arranged on an actuator of the welding device, the welding gun and the vision sensor move along with the actuator, and the relative positions of the welding gun and the vision sensor remain unchanged, the welding control method comprises:

controlling the welding gun to move to an initial position, and determining a welding seam starting point of the workpiece by utilizing the visual sensor;

Controlling the welding gun to move towards the welding seam starting point, and acquiring welding seam data by utilizing the visual sensor;

When the moving distance of the welding gun is larger than a preset value, judging whether the welding seam data acquired by the visual sensor contain a welding seam termination point or not;

if yes, generating a welding track from the welding seam starting point to the welding seam ending point according to the welding seam data, and controlling the welding gun to weld the workpiece according to the welding track;

if not, generating a trend space straight line according to the actual motion data of the welding gun, calculating a corrected coordinate point according to the trend space straight line, the welding line data and a similar triangle rule, and controlling the welding gun to move towards the corrected coordinate point until the welding line data acquired by the visual sensor contains the welding line termination point.

Optionally, generating a trend spatial line according to the actual motion data of the welding gun includes:

Selecting a first actual swing track point and a second actual swing track point from the actual motion data of the welding gun; the moment corresponding to the second actual swing track point is later than the moment corresponding to the first actual swing track point;

And calculating trend space straight lines corresponding to all motion coordinate points from the first actual swing track point to the second actual swing track point by using a least square straight line fitting algorithm.

Optionally, calculating a corrected coordinate point according to the trend space line, the weld data and a similar triangle rule includes:

Determining a first vertical line passing through the first actual swing track point and perpendicular to the trend space straight line, and setting an intersection point of the first vertical line and the trend space straight line as a first intersection point;

Determining a second vertical line which passes through the second actual swing track point and is perpendicular to the trend space straight line, and setting an intersection point of the second vertical line and the trend space straight line as a second intersection point;

calculating the deviation of the actual groove center point according to the weld joint data, the current swing and the deviation data;

Calculating a similar triangle rule based on dynamic displacement according to the coordinates of the first intersection point, the coordinates of the second intersection point and the deviation of the center point of the actual groove to obtain motion differential offset of the welding gun in the directions of an X axis, a Y axis and a Z axis;

And calculating the corrected coordinate point according to the motion differential offset and the coordinates of the second intersection point.

Optionally, controlling the welding gun to move to the corrected coordinate point until the welding seam data collected by the vision sensor includes the welding seam termination point includes:

step 1: controlling the welding gun to move towards the corrected coordinate point, and judging whether the welding seam data acquired by the visual sensor contain the welding seam termination point or not; if yes, judging that the welding seam termination point is contained in the welding seam data acquired by the visual sensor; if not, entering step 2;

step 2: re-selecting a first actual swing track point and a new second actual swing track point from the actual motion data of the welding gun;

Step 3: calculating trend space straight lines corresponding to all motion coordinate points from the first actual swing track point to the second actual swing track point by utilizing a least square space straight line algorithm;

Step 4: and (3) calculating a new corrected coordinate point according to the trend space straight line, the welding line data acquired by the visual sensor and the similar triangle rule, and entering into the step (1).

Optionally, calculating the actual groove center point deviation according to the weld data, the current swing and the deviation data includes:

Calculating groove center point deviation according to the welding line data;

Determining the current swing amplitude according to the swing waveform and the working time of the welding gun;

Subtracting the current swing and deviation data from the groove center point deviation to obtain an actual groove center point deviation of the actual groove center point deviation in the Y-axis and Z-axis directions; the deviation data comprise deviations of the welding gun and the visual sensor in the Y-axis direction and the Z-axis direction, and the movement direction of the welding gun is the X-axis direction.

Optionally, determining whether the weld data collected by the vision sensor includes a weld termination point includes:

judging whether the welding seam data acquired by the visual sensor contain a welding seam termination point or not according to a system scanning period.

Optionally, generating a welding track from the welding seam starting point to the welding seam ending point according to the welding seam data includes:

And fitting the welding seam data through a median filtering method to obtain welding seam characteristic points, and calculating the welding seam characteristic points through a least square straight line fitting algorithm to obtain the welding track from the welding seam starting point to the welding seam ending point.

The application also provides a welding control system which is applied to welding equipment, wherein a welding gun and a visual sensor are arranged on an actuating mechanism of the welding equipment, the welding gun and the visual sensor move along with the actuating mechanism, and the relative positions of the welding gun and the visual sensor are kept unchanged, and the welding control system comprises:

The starting point determining module is used for controlling the welding gun to move to an initial position and determining a welding seam starting point of the workpiece by utilizing the visual sensor;

the data acquisition module is used for controlling the welding gun to move towards the welding seam starting point and acquiring welding seam data by utilizing the visual sensor;

the judging module is used for judging whether the welding seam data acquired by the visual sensor contain a welding seam termination point or not when the moving distance of the welding gun is larger than a preset value;

the operation module is used for generating a welding track from the welding seam starting point to the welding seam ending point according to the welding seam data if the welding seam data acquired by the visual sensor contains the welding seam ending point, and controlling the welding gun to weld the workpiece according to the welding track;

and the correction module is used for generating a trend space straight line according to the actual motion data of the welding gun if the welding seam data acquired by the visual sensor does not contain the welding seam termination point, calculating a correction coordinate point according to the trend space straight line, the welding seam data and a similar triangle rule, and controlling the welding gun to move towards the correction coordinate point until the welding seam data acquired by the visual sensor contains the welding seam termination point.

The application also provides a storage medium on which a computer program is stored, which when executed implements the steps of the above welding control method.

The application also provides welding equipment, which comprises an executing mechanism, a memory and a processor, wherein the executing mechanism is provided with a welding gun and a vision sensor, the welding gun and the vision sensor move along with the executing mechanism, the relative positions of the welding gun and the vision sensor are kept unchanged, the memory is stored with a computer program, and the processor realizes the steps of the welding control method when calling the computer program in the memory.

The application provides a welding control method, which is applied to welding equipment, wherein a welding gun and a visual sensor are arranged on an actuating mechanism of the welding equipment, the welding gun and the visual sensor move along with the actuating mechanism, and the relative positions of the welding gun and the visual sensor are kept unchanged, and the welding control method comprises the following steps: controlling the welding gun to move to an initial position, and determining a welding seam starting point of the workpiece by utilizing the visual sensor; controlling the welding gun to move towards the welding seam starting point, and acquiring welding seam data by utilizing the visual sensor; when the moving distance of the welding gun is larger than a preset value, judging whether the welding seam data acquired by the visual sensor contain a welding seam termination point or not; if yes, generating a welding track from the welding seam starting point to the welding seam ending point according to the welding seam data, and controlling the welding gun to weld the workpiece according to the welding track; if not, generating a trend space straight line according to the actual motion data of the welding gun, calculating a corrected coordinate point according to the trend space straight line, the welding line data and a similar triangle rule, and controlling the welding gun to move towards the corrected coordinate point until the welding line data acquired by the visual sensor contains the welding line termination point.

The welding equipment provided by the application comprises the welding gun and the visual sensor, wherein the welding gun and the visual sensor synchronously move, the visual sensor is utilized to monitor the welding seam of the workpiece in real time, and the welding gun is controlled to execute welding operation based on the detected welding seam data so as to provide guiding information for the tracking of the welding seam. Generating a trend space straight line based on the actual movement data of the welding gun, and calculating a correction coordinate point according to the trend space straight line, the welding line data and a similar triangle rule; when the welding gun track has deviation, the correction coordinate point can correct the welding gun into the welding seam area, ensure that the welding gun is executed in the welding seam area, and simultaneously ensure the stable dry extension length of the welding wire. The application also provides a welding control system, a storage medium and welding equipment, which have the beneficial effects and are not repeated herein.

Drawings

For a clearer description of embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described, it being apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.

FIG. 1 is a flow chart of a welding control method according to an embodiment of the present application;

FIG. 2 is a schematic diagram of an automatic weld seam tracking method according to an embodiment of the present application;

FIG. 3 is a schematic view of an original point cloud of a cross-sectional image of a weld groove according to an embodiment of the present application;

FIG. 4 is a cross-sectional view of a weld groove after median filtering according to an embodiment of the present application;

FIG. 5 is a schematic diagram of a trend space after fitting according to an embodiment of the present application;

FIG. 6 is a graph showing the trend of swing welding swing with time according to the embodiment of the present application;

FIG. 7 is a graph of an analysis of a differential-magnitude dynamic tracking algorithm according to an embodiment of the present application;

FIG. 8 is a flowchart of an automatic weld seam tracking method provided by an embodiment of the present application;

FIG. 9 is a schematic diagram of trace comparison of an embodiment of the present application with a conventional weld tracking scheme;

FIG. 10 is a graph showing the weld trace convergence effect of an embodiment of the present application versus a conventional weld trace tracking scheme.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

Referring to fig. 1, fig. 1 is a flowchart of a welding control method according to an embodiment of the present application, which includes the following specific steps:

s101: controlling the welding gun to move to an initial position, and determining a welding seam starting point of the workpiece by utilizing the visual sensor;

The embodiment can be applied to welding equipment, wherein a welding gun and a visual sensor are arranged on an actuating mechanism of the welding equipment, the welding gun and the visual sensor move along with the actuating mechanism, and the relative positions of the welding gun and the visual sensor are kept unchanged.

The visual sensor includes, but is not limited to, a 3D camera and a laser sensor, and is used for acquiring characteristics of an object (such as a workpiece) to be identified, acquiring complete, clear and stable weld joint data (such as weld joint section image information and depth information), and providing guiding information for follow-up weld joint tracking.

The welding device or welding system may be started prior to this step and internal data of the device or system may be initialized to automatically operate the welding gun to the initial position. After the welding gun is moved to the initial position, a visual sensor may be used to search for a weld start point. Specifically, the profile obtained by scanning by using the visual sensor can be automatically matched with the target profile, and after N times of successful matching are obtained, the welding seam starting point is obtained according to the previous N times of matching results. The target profile may be a profile of a standard workpiece weld, and a standard weld starting point may be marked on the profile of the standard workpiece weld, where the embodiment determines the weld starting point by matching the actually collected profile with the target profile.

S102: controlling the welding gun to move towards the welding seam starting point, and acquiring welding seam data by utilizing the visual sensor;

Wherein, before this step, there may be an operation of judging whether to acquire the weld starting point successfully, and if the acquisition of the weld starting point succeeds, the vision sensor is located at the weld starting point, and the welding gun may be controlled to move toward the weld starting point (e.g., to run along the X-axis direction), during which the vision sensor detects the initial section of the weld. And fitting welding seam characteristic points of welding seam data obtained by the vision sensor through a median filtering method from the detection starting point to the welding gun starting point to be welded, namely the front distance of the vision sensor, and fitting n groups of welding seam midpoints. The points in the n groups of welding seams are combined into a plurality of points { (xi, yi, zi) |1 is not less than i is not more than n }, and a least square straight line fitting combination algorithm is applied to obtain an operation trend track of the initial section of the welding seams and the operation trend track is cached in a system. If the acquisition of the weld starting point is unsuccessful, the operation of searching the weld starting point is executed again until the acquisition of the weld starting point is successful. After the welding gun moves to the starting point of the welding line, the welding work can be started. The welding gun can execute work according to the welding track of the cached welding seam initial section, and the actual motion coordinate point is transmitted to the system for caching according to the scanning frequency of the control system, and meanwhile, the visual sensor at the front end acquires welding seam data (such as welding seam images).

S103: when the moving distance of the welding gun is larger than a preset value, judging whether welding seam termination points are contained in welding seam data acquired by the visual sensor; if yes, go to step S104; if not, entering S105;

The preset value specifically refers to a distance for starting to correct a movement track of the welding gun, and when the movement distance of the welding gun is greater than the preset value, the related operations of S103-S105 can be executed, and the preset value can be determined according to a distance between the welding gun and the vision sensor, and the distance is positively related to the preset value. The moving distance of the welding gun refers to the distance that the welding gun moves after starting from the initial position. Specifically, in this embodiment, whether the weld seam termination point is included in the weld seam data collected by the vision sensor may be determined according to a system scanning period.

S104: generating a welding track from the welding seam starting point to the welding seam ending point according to the welding seam data, and controlling the welding gun to weld the workpiece according to the welding track;

The welding seam starting point is the starting point of the welding operation, the welding seam ending point is the ending point of the welding operation, and when the visual sensor collects the welding seam ending point, a welding track from the welding seam starting point to the welding seam ending point can be generated according to welding seam data collected in the moving process so as to instruct the welding gun to weld the workpiece according to the welding track. Specifically, in this embodiment, the weld bead characteristic points may be obtained by fitting the weld bead data by a median filtering method, and the welding track from the weld bead start point to the weld bead end point may be obtained by calculating the least square straight line fitting algorithm for the weld bead characteristic points.

S105: generating a trend space straight line according to actual motion data of a welding gun, calculating a corrected coordinate point according to the trend space straight line, the welding line data and a similar triangle rule, and controlling the welding gun to move towards the corrected coordinate point until the welding line data acquired by the visual sensor contains the welding line termination point.

If the vision sensor does not detect the welding seam termination point, generating a trend space straight line of the welding gun for actual operation according to actual motion data of the welding gun, further calculating a correction coordinate point based on the trend space straight line, the welding seam data collected by the vision sensor and a similar triangle rule, and controlling the welding gun to move towards the correction coordinate point until the welding seam termination point is contained in the welding seam data collected by the vision sensor. After the welding gun is controlled to move towards the corrected coordinate point, whether the welding seam data newly acquired by the visual sensor contains a welding seam termination point or not can be judged, and if so, S104 is carried out; and if the welding seam termination point is not included, generating a new corrected coordinate point and controlling the welding gun to move to the new corrected coordinate point. The operation of searching the welding seam end point is similar to the operation of searching the welding seam starting point, and the actually acquired contour can be obtained by matching the target contour. The trend space straight line is used for describing the actual movement trend of the welding gun. The similar triangle rule can be a similar triangle rule based on dynamic displacement, specifically, a similar triangle can be constructed according to the differential proportion of the welding gun in the X, Y, Z axis direction to obtain the motion differential offset in the Y, Z axis direction, and the corrected coordinate point is determined according to the motion differential offset.

The welding equipment provided by the embodiment comprises the welding gun and the visual sensor, wherein the welding gun and the visual sensor synchronously move, the visual sensor is utilized to monitor the welding seam of the workpiece in real time, and the welding gun is controlled to execute welding operation based on the detected welding seam data so as to provide guiding information for the tracking of the welding seam. The embodiment also generates a trend space straight line based on the actual movement data of the welding gun, and calculates a correction coordinate point according to the trend space straight line, the welding line data and a similar triangle rule; when the welding gun track has deviation, the correction coordinate point can correct the welding gun into the welding seam area, so that the welding gun is ensured to be arranged in the welding seam area, and meanwhile, the stable welding wire dry extension length is ensured.

Further introduction to the corresponding embodiment of FIG. 1, the job trend line may be generated by: selecting a first actual swing track point and a second actual swing track point from the actual motion data of the welding gun; the moment corresponding to the second actual swing track point is later than the moment corresponding to the first actual swing track point; and calculating trend space straight lines corresponding to all motion coordinate points from the first actual swing track point to the second actual swing track point by using a least square straight line fitting algorithm.

Accordingly, taking an example that the actual motion data includes the first actual swing track point and the second actual swing track point, the embodiment may calculate the corrected coordinate point by: determining a first vertical line passing through the first actual swing track point and perpendicular to the trend space straight line, and setting an intersection point of the first vertical line and the trend space straight line as a first intersection point; determining a second vertical line which passes through the second actual swing track point and is perpendicular to the trend space straight line, and setting an intersection point of the second vertical line and the trend space straight line as a second intersection point; calculating the deviation of the actual groove center point according to the weld joint data, the current swing and the deviation data; calculating a similar triangle rule based on dynamic displacement (as shown in fig. 7) on the coordinates of the first intersection point, the coordinates of the second intersection point and the deviation of the center point of the actual groove to obtain motion differential offsets of the welding gun in the directions of an X axis, a Y axis and a Z axis; and calculating the corrected coordinate point according to the motion differential offset and the coordinates of the second intersection point.

Specifically, the searching for the weld end point in this embodiment may include:

Step A1: controlling the welding gun to move towards the corrected coordinate point, and judging whether the welding seam data acquired by the visual sensor contain the welding seam termination point or not; if yes, judging that the welding seam termination point is contained in the welding seam data acquired by the visual sensor; if not, entering a step A2;

Step A2: re-selecting a first actual swing track point and a new second actual swing track point from the actual motion data of the welding gun;

Step A3: calculating trend space straight lines corresponding to all motion coordinate points from the first actual swing track point to the second actual swing track point by utilizing a least square space straight line algorithm;

step A4: and (3) calculating a new corrected coordinate point according to the trend space straight line, the welding line data acquired by the visual sensor and the similar triangle rule, and entering a step A1.

Specifically, the calculation of the actual groove center point deviation according to the present embodiment may include: calculating groove center point deviation according to the welding line data; determining the current swing amplitude according to the swing waveform and the working time of the welding gun; subtracting the current swing and deviation data from the groove center point deviation to obtain an actual groove center point deviation of the actual groove center point deviation in the Y-axis and Z-axis directions; the deviation data comprise deviations of the welding gun and the visual sensor in the Y-axis direction and the Z-axis direction, and the movement direction of the welding gun is the X-axis direction.

The above procedure is exemplified below, the first actual swing track point isThe second actual swing track point isThe corrected coordinate point isWhen the welding gun is positionedThe visual sensor is located at P _A' when the welding gun is located atThe time-dependent visual sensor is located at P _B',

The gun moves to a proximity sensor detection point P _A' (i.e., point)) Or move to the correction pointAnd automatically matching the profile obtained by scanning by using the sensor with the target profile, and obtaining the X-axis coordinate of the welding seam termination point according to the previous N times of matching results after N times of successful matching are unsuccessful. If the end point of the welding line is successfully obtained, the data cached in the system before is adopted, so that the tracking track is kept on the corrected preset track until the welding is finished. If the acquisition of the welding seam termination point is unsuccessful, the following steps are carried out:

a) Reach of welding gun Dots orThen, the cached welding starting point is connected toDots orAnd calculating the actual welding operation trend space straight line L ₁ by the coordinates of all the actually arrived track points.

B) Welding gun atAt point (i.e. sensor is close toPoint), the position of a welding line center line is calculated and cached through median filtering and linear fitting of welding line information acquired by a visual sensor at a detection point P _A', and a similar triangle rule based on dynamic displacement is adopted in combination with a trend space straight line L ₁ to obtain differential offset Thereby calculating the next target control point, i.e. correction pointAnd sending the coordinates to an executing mechanism for control.

The embodiment can repeat the above steps when the welding gun moves to the correction pointAnd after correction in the Y-axis direction and the Z-axis direction is carried out, searching for a welding seam termination point in the next system scanning period until the welding seam termination point is searched.

Referring to fig. 2, fig. 2 is a schematic diagram of an automatic weld seam tracking method according to an embodiment of the present application, in fig. 2, 1 represents an end effector, 2 represents a track, 3 represents a workbench, 4 represents a workpiece, 5 represents a welding gun, 6 represents a weld seam, and 7 represents a vision sensor. The embodiment can solve the problem of poor convergence of the tracking track when the welding seam has abrupt change in the existing tracking method, and ensure that the welding gun works in the welding seam area. In the automatic weld tracking process, the weld seam is detected in real time based on the front-end visual sensor, the depth information and the section information are contained, and the current welding gun position information and the detection data of the sensor are cached. The actuating mechanism of the embodiment can be a track type trolley, the welding equipment comprises a motion control system and a central processing unit, the motion control system transmits motion target point information to the central processing unit, the central processing unit transmits position and speed information of each shaft to the motion control system, and the vision sensor transmits welding seam image information to the central processing unit. As shown in fig. 2, the relative positions of the end effector and the workpiece to be welded are kept unchanged as much as possible during the welding operation. An end effector gun and vision sensor are mounted to the end effector for movement therewith. In the welding process, the relative positions of the welding gun and the visual sensor are kept unchanged, and the angle of the welding gun in the XYZ moving direction is consistent with that of the visual sensor in the XYZ detecting direction. The end actuating mechanism is driven by at least 3 motors, can freely move in the XYZ axis direction, and sets the position coordinates of the sensor and the position coordinates of the welding gun to be F, W, H respectively in the XYZ direction. In the welding process, the executing mechanism drives the welding gun to execute swinging operation along the welding line of the workpiece until the groove is uniformly filled. The visual sensor can set a scanning period, the welding seam depth information and the groove section profile information are obtained in real time in the welding operation process, and the deviation data of a welding seam center point and a welding gun are finally obtained through data processing and fitting calculation in the central processing unit, so that the purpose of guiding an executing mechanism to carry a welding gun to dynamically compensate in the direction of eliminating errors is achieved.

The motion control system comprises a PLC (Programmable Logic Controller, a programmable logic controller), a motor driver and a motor. The PLC signal input end and the output end are connected with the signal end in the motor driver, the speed and the position of the motor of the actuating mechanism are controlled through high-speed pulses sent by the PLC output end, and the running speed and the real-time position of the motor of the actuating end are fed back to the PLC input end in real time through the driver. The PLC communication module is connected with the central processing unit communication module through a bus communication mode and adopts a TCP/IP mode for communication. The scanning period of the PLC is set to be 10-100 ms, and the position and speed information of each shaft motor is sent to the central processing unit in real time according to the scanning period. The scanning period of the central processing unit is set to be 10-100 ms, the central processing unit communication unit sends the moving target control point to the CPU of the PLC according to the scanning period, the CPU in the PLC calculates the pulse number and the pulse output frequency, and finally, each shaft motor is controlled to reach the target point position according to the set speed. The CPU communication unit is used for receiving real-time data of each shaft execution motor sent by the PLC, caching the data into the storage unit and finally realizing on-line monitoring and control of the execution mechanism. The central processing unit is used for processing data, the computing unit calls a computer program stored in the storage unit and is used for executing online monitoring with the PLC data, processing detection data acquired by the vision sensor, executing a differential dynamic operation compensation algorithm, calculating the coordinates of a swing operation track target point, finally sending the swing operation track target point to the motion control system through the communication unit, realizing the motion of the executing mechanism to the target point, and dynamically rectifying deviation in the direction of eliminating the weld deviation. The CPU storage unit is used for caching the track point data actually arrived by the mechanism, storing data processing and calculating a target point program. The embodiment can adopt a mature robot to replace an executing mechanism, adopts a singlechip to control to replace a PLC controller, and replaces a communication mode of a motion control system and a central processing unit through a wired network or a wireless 4G and wireless 5G network. The present embodiment may also employ the calculation of the welding trend spatial line L ₁ by fitting the weld characteristic points detected by the sensor.

The implementation process of the automatic welding seam tracking method executed in the central processing unit is as follows:

Step B1, starting a system to start working, initializing internal data of the system, and automatically running a welding gun to an initial position;

And B2, searching a welding seam starting point, automatically matching the contour obtained by scanning by using a visual sensor with a target contour, and obtaining the welding seam starting point according to the previous N times of matching results after obtaining N times of successful matching.

And B3, if the welding seam starting point is successfully obtained, the sensor is positioned at the welding seam starting point, the welding gun runs along the X-axis direction, the sensor detects the welding seam of the initial section, the welding seam data obtained by the sensor is fitted to the welding seam characteristic points through a median filtering method from the detection starting point to the welding gun starting point to be welded, namely the front distance of the sensor, and n groups of welding seam midpoints are fitted. The points in the n groups of welding seams are combined into a plurality of points { (xi, yi, zi) |1 is not less than i is not more than n }, and a least square straight line fitting combination algorithm is applied to obtain an operation trend track of the initial section of the welding seams and the operation trend track is cached in a system. If the weld joint starting point is not successfully obtained, returning to the step 2, and repeating until the weld joint starting point is successfully obtained.

Step B4, enabling the welding gun to reach a welding seam starting point along the X-axis direction, and starting welding work;

and B5, executing work according to the cached welding track of the initial section of the welding seam, transmitting the actual motion coordinate point to the system for caching according to the scanning frequency of the control system, and simultaneously acquiring the welding seam image by a visual sensor at the front end.

Step B6, the welding gun moves to the proximity sensor detection point P _A' (i.e. point)) Or move to the correction pointAnd automatically matching the profile obtained by scanning by using the sensor with the target profile, and obtaining the X-axis coordinate of the welding seam termination point according to the previous N times of matching results after N times of successful matching are unsuccessful. If the end point of the welding line is successfully obtained, the data cached in the system before is adopted, so that the tracking track is kept on the corrected preset track until the welding is finished. If the acquisition of the welding seam termination point is unsuccessful, the following steps are carried out:

a) Reach of welding gun Dots orThen, the cached welding starting point is connected toDots orAnd calculating a trend space straight line L ₁ by the coordinates of all the actually arrived track points.

B) Welding gun atAt point (i.e. sensor is close toPoint), the position of a welding line center line is calculated and cached through median filtering and linear fitting of welding line information acquired by a visual sensor at a detection point P _A', and a similar triangle rule based on dynamic displacement is adopted in combination with a trend space straight line L ₁ to obtain differential offset Thereby calculating the next target control point, i.e. correction pointAnd sending the coordinates to an executing mechanism for control.

Step B7, repeating step B6, when the welding gun moves to the correction pointAnd after correction in the Y-axis direction and the Z-axis direction is carried out, searching for a welding seam termination point in the next system scanning period until the welding seam termination point is searched.

According to the method, the coordinate points of the welding gun are actually achieved, the operation trend straight line is fitted, the coordinates of the correction points are calculated, when the execution track of the welding gun is deviated in the welding process, the welding gun can be corrected to the welding seam area, the correction track is smooth, the welding gun of the execution tool is ensured to be in the welding seam area, meanwhile, the stable welding wire dry extension length is ensured, the anti-interference capability is high, the tracking precision is high, and the welding seam tracking can be efficiently finished in real time. In the embodiment, the position of the correction point is calculated once in each scanning period of the system, the position of the correction point is close to the detection point, and the compensation distance between the detection point and the correction point is shortened. And the weld tracking correction is carried out in each scanning period, so that the real-time performance of dynamic tracking is improved, and the tracking convergence effect is enhanced. The Y-direction and Z-direction real-time correction is carried out during welding, so that the welding line correction device can be suitable for zigzag welding lines, swing welding, changes in workpiece height and welding line tracking of workpiece deformation in the welding process, and is convenient for system use and popularization.

Specifically, in steps B2 to B7, the executing mechanism carries a vision sensor to scan and collect images of the weld groove at a constant speed along the X-axis direction, that is, the working direction, and the vision sensor image collecting module scans the 2D profile of the groove cross section to obtain a weld point cloud, wherein the exposure degree of the vision sensor is 20 to 40, and the binarization threshold is 114 to 124, and the two are combined together to adjust the real, virtual and stability of the obtained point cloud data, so as to obtain an original point cloud of the groove cross section image, as shown in fig. 3, and fig. 3 is a schematic diagram of the original point cloud of the weld groove cross section image provided by the embodiment of the application. In order to remove noise in an original image point cloud and retain contour information in a groove cross-section image, a median filtering method is adopted in a central processing unit to obtain a median filtered image, as shown in fig. 4, and fig. 4 is a weld groove cross-section image after median filtering processing provided by the embodiment of the application. Noise can be effectively restrained by a median filtering method, the value of one point in the digital sequence is replaced by the median value of each point value in a neighborhood of the point, and the surrounding point cloud value is close to the true value, so that isolated noise points are eliminated. The embodiment can improve the accuracy of straight line extraction, thereby improving the accuracy of the section profile.

In the step B2 and the step B6, the initial point and the end point of the welding seam are detected, N frames of welding seam cross-section images are acquired by utilizing a visual sensor, the welding seam cross-section contour images are extracted through median filtering, and the extracted image contours and the target contours are automatically matched. After N times of successful matching are obtained, the X coordinate position of the welding starting point is obtained according to the previous N times of matching results, and if the matching is unsuccessful, the X coordinate position of the welding end point is obtained.

In the steps B2-B6, linear fitting is carried out on the characteristic points and the break points of the laser profile, and the characteristic points of the welding seam, namely the center point of the groove, are obtained by taking the straight line intersection points of the two sides of the groove as the characteristic points of the welding seam.

In step B3, the initial stage of weld detection is the leading distance F between the welding gun and the vision sensor (i.e. the distance between the welding gun and the vision sensor in the X-axis direction), and the actuator-carried sensor operates at uniform speed along the X-axis. In the motion process, n pieces of section information are collected by the vision sensor, groove section point cloud data of corresponding detection points can be matched according to X-axis coordinate changes, and n welding seam characteristic points, namely (xi, yi, zi), (i=1, 2,...

By adopting a space linear least square fitting method, a trend center point fitting straight line L0 can be obtained in space, a given number of points { (xi, yi, zi) |1 +.i +.n } are assumed, and for the best fitting straight line, groove center points pass through or are close to the points as much as possible, as shown in FIG. 5, FIG. 5 is a trend space linear schematic diagram after fitting provided by the embodiment of the application, a welding gun takes the straight line L0 as the center point, and swing is taken as the swingThe positive or negative swing operation is carried out in the Y direction, or the swing amplitude isAnd performing positive or negative swing operation in the Z direction. The three axes in fig. 5 represent the X-axis, Y-axis, and Z-axis. The trend of swing welding swing with time is shown in fig. 6, fig. 6 is a graph of the trend of swing welding swing with time provided by the embodiment of the application, W in fig. 6 represents the maximum swing,The real-time swing during welding is represented, and the T swing represents the moment when the real-time swing is 0. If need not swing welding, swingAndAll 0.

The spatial line least squares fit, the spatial line L0 is in simplified form:

That is to say,

A, b, c, d in the above represents the slope and intercept of the spatial line

The conversion into a matrix form is as follows:

The groove center point I is as follows:

Then there are:

Multiplication from left to right Then there is

Finally, calculate

In the steps B4 and B5, the welding gun moves to the starting point of the welding seam, the executing mechanism executes work according to the cached operation track of the initial section of the welding seam, namely the welding gun swings in the Y-axis direction or the Z-axis direction based on the fitting straight line L ₀ of the trend center point, the actual motion coordinate point data is transmitted to the system for caching according to the scanning period of the system in real time through the motion control system, and meanwhile, the visual sensor at the front end acquires the image of the welding seam.

In step B6, searching for the end point of the weld during the welding operation, such as unsuccessful acquisition of the end point of the weld, when the X-axis coordinate of the tool gun is close to F, i.e. the gun moves to a point close to the point corresponding to the start point of the weld, i.e.After the point, the swing compensation deviation rectifying work is started to be executed by using the differential offset, as shown in fig. 7, fig. 7 is an analysis chart of a differential dynamic tracking algorithm provided by the embodiment of the application.

Actual swing track point of welding gunPoint(s)When the welding gun is positioned at the pointWhen the visual sensor is positioned at the detection point P _A'. When the welding gun is positioned at the pointWhen the sensor is positioned at the detection point P _B', the pointAt the point ofAnd the current vision sensor inspection point P _A'.

Motion track point of welding gun of actuating mechanismWill beTo all m motion coordinate points of the weld joint starting point, assume that a number of points { (xi, yi, zi) i 1 is less than or equal to i is less than or equal to n }, and a new trend space line L ₁ can be fitted by using the least square space line algorithm, namely:

Track point determination Point(s)Foot drop points P _A and P _B, passing through points, with the trend space line L ₁ The straight line perpendicular to the new trend space straight line L ₁ is L _A,L_A space straight line:

b _A and d _A are the intercepts of the L _A straight lines, b ₁ and d ₁ are the intercepts of the L ₁ straight lines, and the L _A straight line intersects the L ₁ straight line at the locus point P _A.

Wherein the method comprises the steps ofFor the real-time values of the actuator coordinates, which are already buffered in the system, the values of b _A and d _A can be determined here, the setpointIntersection point P _A＝(X_A,Y_A,Z_A with new trend space line L ₁);

The point P _A simultaneously satisfies the new trend space straight line L ₁ equation and the space straight line L _A equation perpendicular to the new trend space straight line L ₁ equation, namely:

The coordinate P _A(X_A,Y_A,Z_A) can be obtained by the above formula, and the passing point can be calculated by the same method A line L _B with points perpendicular to the new trend space line L ₁:

b _B and d _B are the intercepts of the L _B straight line, and the L _B straight line intersects the L ₁ straight line at the locus point P _B.

The point P _B simultaneously satisfies the new trend space line L ₁ and the space line L _B perpendicular thereto, and the coordinate P _B(X_B,Y_B,Z_B) can be obtained, so that the two points P _A,P_B on the new trend space line L ₁ deviate as follows:

X_AB＝X_A-X_B

Y_AB＝Y_A-Y_B

Z_AB＝Z_A-Z_B

Welding gun is at The point, the visual sensor is at the detection point P _A', the center point of the groove can be calculated through the median filtering and fitting in the step B4, and the Y-axis deviation is as followsAs shown in FIG. 7, the Z-axis deviation isRespectively subtracting the current real-time swingAndSubtracting the deviation F, W, H of the welding gun and the vision sensor in the XYZ direction, the deviations of the actual groove center point in the Y and Z axis directions are respectively:

Wherein the method comprises the steps of The swing amplitude can be calculated according to the swing waveform and the working time period, and as shown in FIG. 6, if swing welding is not needed, the swing amplitudeIs 0.

In the XOY plane, referring to a similar triangle as shown in fig. 7, the differential ratio of X to Y directions can be calculated:

similarly, in the XOZ plane, the differential ratio between the X and Z directions can be obtained:

The operation speed of the welding gun on the X axis is Vx, the scanning period is T _S, and the differential quantity in the X direction in one scanning period is as follows:

y, Z differential offset of direction motion:

the differential deviation is calculated by the detection point, so that a new movement center point can be calculated I.e. a point close to P _B, correction pointCenter pointThe motion center point coordinates of the correction point areWherein:

Real-time swing in Y-axis direction Real-time swing in Z-axis directionThe swing amplitude can be estimated from the swing waveform and the operating time period as shown in fig. 6.

Welding gun spotIs taken as a center, and the motion target point coordinates are

In step a, as shown in FIG. 7, when the welding gun is inWhen in point, the point is cachedThe method comprises the steps of (1) combining all m motion coordinate points from a point to a weld joint starting point, wherein the number of the m motion coordinate points is { (xi, yi, zi) |1 is not less than i is not more than n }, fitting a trend space straight line L ₁ by using a least square algorithm, and calculating to obtain a group of two points P _A and P _B, wherein P _B is an actual motion trackThe perpendicular foot intersection point of the point and the trend space straight line L ₁, P _A is the actual motion trailThe point intersects the foot drop of trend spatial line L ₁.

In step b, the welding gun is atAt the point, the sensor detects Y-axis data measured at the pointAnd Z-axis dataAnd caching the welding gun motion coordinate axis data and the sensor data of the executing mechanism at the moment. When the actuator gun moves to the point of approach P _A', i.e. atAt the point, the welding gun is used forWhen in point, the vision sensor calculates the correction point by referring to the data measured by the vision sensor at the detection point P _A' and referring to the similar triangle differential offset algorithmAnd (3) guiding the welding gun to move to the correction point by coordinates, and correcting the Y direction and the Z direction. The method increases the real-time property of the tracking data, strengthens the tracking convergence effect of the welding seam, and enables the calculated track to be closer to the actual welding seam.

When repeating steps B6-B7, in steps a, B, when the welding gun is operated to the pointWhen in use, the point is cachedIs the actual coordinates of (i) pointsBonding pointsTo m+1 motion coordinate points of the weld joint starting point, the number of the motion coordinate points is { (xi, yi, zi) |1 is less than or equal to i is less than or equal to n }, a least square algorithm is applied to fit a new trend space straight line L ₁, the slope is changed, a new group of two points P _A,P_B is obtained through calculation, and the new group of P _B is the actual motion track point of the previous groupThe perpendicular foot intersection point with the trend space straight line L ₁, P _A is the actual motion track point of the previous groupAnd a foot drop intersection with the trend spatial line L ₁. The welding gun is at the track point beforeWhen the sensor detects the current detection point, the data measured by the sensor compensates the new correction pointAnd (6) repeating the step until the sensor searches the welding seam end point.

According to the embodiment, an operation trend space straight line of a welding actual track is calculated by using an actual motion track point brought-in least square algorithm, the straight line is brought into a differential motion dynamic compensation algorithm, a correction point is calculated in each scanning period, actual motion data and sensor detection data are fused and calculated, the overall fault tolerance of the system is improved, and a welding gun is ensured to be in a welding seam range. The embodiment provides a differential dynamic tracking algorithm, reduces the compensation distance between the detection point and the correction point, corrects the deviation in the Y and Z directions, and can guide a welding gun tool in the welding seam through the algorithm even if the welding seam has mutation, thereby increasing the real-time performance of tracking data and strengthening the tracking convergence effect; in the embodiment, the motion target point is calculated once in each system scanning period, and the target point position arrival is executed once in each system scanning period, so that the operation error can be effectively reduced, and the tracking precision is improved.

Because the sensor and the welding gun have the front distance, the welding correction is not real-time, and the embodiment now introduces a differential dynamic operation compensation algorithm, reduces the compensation distance between the detection point and the correction point, and increases the real-time performance of the weld tracking. Meanwhile, the installation distance between the sensor and the welding gun tool can be increased, and the influence of noise such as arc light, scattered laser, metal splash, reflection and the like existing in the welding process on the image acquisition of the sensor is reduced. In the welding process, the embodiment brings the visual sensor detection data into a differential quantity dynamic compensation algorithm, calculates the weld deviation in each scanning period, and executes correction in Y and Z directions once in each scanning period. When the position of the welding line changes (thermal deformation in the welding process) or the actuating mechanism moves, the deviation between the welding line and the welding gun can be calculated in real time, and real-time deviation correction is executed, so that the welding gun is ensured to be in the welding line area, the problem of low convergence speed caused by overlarge sensor front distance in the traditional tracking algorithm is solved, and the tracking effect is improved. For the operation of repeated structural members, the starting point can be intelligently identified without teaching the starting point; when the deviation between the welding gun and the welding line is larger due to the misoperation of the executing mechanism in the welding process, the actual motion track point is brought into an algorithm, the target track of the correction point is calculated, a smoother welding track can be formed, the shaking of the welding gun in the welding process is weakened, and the fault tolerance of the executing system can be increased.

Referring to fig. 8, fig. 8 is a flowchart of an automatic weld seam tracking method according to an embodiment of the present application, and the specific implementation process is as follows: after the system is initialized, starting to search a weld joint starting point, automatically matching the profile obtained by the sensor (visual sensor) with the target profile, and obtaining the weld joint starting point according to the previous N times of matching results after N times of successful matching are obtained. Judging whether the sensor is positioned at the weld joint starting point, if not, searching the weld joint starting point again, and if so, detecting the weld joint at the front end by using the sensor. And obtaining a welding track of the initial end of the welding seam through a median filtering and least square pointing fitting combination algorithm. And after the welding gun reaches the starting point of the welding seam, welding according to the welding track of the initial section, detecting the welding seam by a sensor, and caching the coordinates of the track point actually reached by the welding gun and the detection data of the sensor. The welding gun moves to a monitoring point close to a sensor or to a correction point, and the sensor detects the welding line. And buffering coordinates of the track points actually reached by the welding gun and detection data of the sensor. And starting the welding seam end point search, automatically matching the contour obtained by the sensor scanning with the target contour, and obtaining the welding seam end point according to the previous N times of matching results after N times of successful matching are obtained. Judging whether the sensor is positioned at the end point of the welding line or not; if yes, the welding gun moves to a welding seam end point according to the cached data; if not, the operation trend space straight line L ₁ is calculated according to the track point coordinates actually reached by the welding gun, the correction point coordinates are calculated according to the calculus offset calculated by using a similar triangle rule based on dynamic displacement, and the movement is controlled according to the correction point coordinates.

Referring to fig. 9 and 10, fig. 9 is a schematic diagram comparing the track of the conventional weld tracking scheme with the track of the embodiment of the present application, and shows the actual weld, the front-end operation trend space straight line, the weld tracking track calculated by the differential dynamic offset algorithm (i.e. the scheme provided in the present embodiment), and the weld tracking track calculated by the conventional algorithm. Fig. 10 is a schematic diagram comparing the welding track convergence effect of the embodiment of the present application with the conventional seam tracking scheme, and shows the actual seam center line, the conventional seam tracking convergence effect (dotted line), and the seam tracking convergence effect (solid line in the middle) after the differential dynamic offset algorithm (i.e. the scheme provided in the present embodiment) is adopted. In order to ensure the reliable and efficient quality of the welding seam welding, the automatic welding is mostly carried out by adopting a welding seam automatic tracking technology. The existing automatic tracking mode based on the welding seam is mainly characterized in that a preposed optical vision sensor is arranged on a welding gun tool of a welding robot, the position of a characteristic point of the welding seam is detected and calculated in real time through the sensor, and the robot is controlled to automatically track and weld according to the position of the characteristic point. The existing weld tracking method has the following defects:

1. And adopting a seam tracking method based on an absolute seam path, and introducing a non-uniform rational B-spline interpolation mode to track the seam. Creating a stack, and caching absolute weld track and weld sampling point coordinates of the laser sensor in the stack. Searching a position coordinate closest to an actual position coordinate PT of the welding gun in the stack, taking the closest position coordinate and 3 position coordinates which are adjacent to the closest position coordinate in front of and behind as control points, carrying out non-uniform rational B spline interpolation, obtaining a deviation Err of the corresponding position coordinate PT' of the actual position coordinate PT of the welding gun on a welding line track in the welding robot, and rectifying the welding robot.

The tracking process in the above manner has a large error in the initial stage, mainly due to the initial positional deviation between the welding gun and the workpiece to be tracked. The deviation of the actual position of the welding gun and the absolute welding seam track deviation in the stack are calculated to correct the deviation, and the method is not suitable for swinging welding tracking of a robot and is not suitable for welding seam tracking of a medium plate.

2. The detected weld characteristic points are two-dimensional information, and then plane linear fitting is carried out on each piece of data to obtain N xy axis coordinates. The groove depth information is not detected, so that the welding tracking correction in the Z-axis direction cannot be realized, the welding tracking correction is not applicable to the working condition that the groove height of the welding line changes, and the stable welding wire dry extension cannot be ensured. According to the three-dimensional coordinates of the robot after the characteristic points of the welding seam are converted, a series of intermediate points are arranged between the starting point and the end point of the path to serve as transition, the pose of the welding robot when the welding robot passes through the intermediate points is controlled, the intermediate points are estimated, the welding seam tracking convergence effect is poor when the welding seam is suddenly changed in the Y direction or the Z direction.

In the embodiment, the three-dimensional vision sensor is adopted to detect the weld groove, the depth and the contour information are included, Y-direction and Z-direction correction can be performed, and the welding operation precision is improved. Based on the vision sensor data, a differential quantity dynamic compensation algorithm is used for calculating the weld joint deviation in each scanning period, and when the welding gun reaches the differential quantity position close to the detection point, the differential quantity is used for dynamically correcting the Y-direction deviation and the Z-direction deviation, so that the operation error can be effectively reduced, and the accuracy of real-time tracking compensation is improved.

3. And obtaining weld characteristic points through active laser vision, and generating a welding track by the TCP points at the end of the robot tool along a weld characteristic point sequence. When the weld tracking is executed, the robot controller establishes a register array and records a laser vision sensor position sequence corresponding to the characteristic points of the weld; and recording Y-direction and Z-direction deviation rectifying values of the TCP points corresponding to the position sequence. The TCP points at the tool end of the robot are finely adjusted in the Y direction and the Z direction along the welding line direction to achieve the deviation correction amount of accurate positioning, interpolation is carried out between adjacent sequence position points of the TCP points at the tool end, and correction in the Y direction and the Z direction is carried out when the positions of each tracked welding line feature point are reached, so that the deviation can be eliminated in the X direction, the Y direction and the Z direction, and the situation that the TCP points at the tool end of the robot reach the expected pose after three-dimensional welding line tracking is ensured. The invention has the problems of more complex system and more control flow nodes, and comprises a vision system controller, a precisely positioned cross sliding table controller, a robot controller and the like, when the cross sliding table at the tail end of the robot moves to a welding seam characteristic point, more uplink and downlink data nodes are arranged during deviation correction, the time of data transmission is increased, and the welding seam tracking data is not real-time, so that the welding quality is affected. The weld tracking method is suitable for a simpler system, reduces data transmission time and has high response speed.

The embodiment provides an automatic welding seam tracking scheme, wherein in the automatic seam tracking process, the welding seam is detected in real time based on a preposed visual sensor, the welding seam tracking scheme comprises depth information and section information, and welding gun position information and corresponding detection data are cached. And a least square algorithm is introduced, coordinate points actually reached by the welding gun are fitted to form an operation trend straight line, a similar triangular differential dynamic offset algorithm is adopted, and when the welding gun reaches a differential position close to a detection point, the differential is utilized to dynamically correct the deviation of the Y direction and the Z direction, so that the real-time tracking of the welding seam in the welding process is realized.

The embodiment of the application also provides a welding control system, which can be applied to welding equipment, wherein a welding gun and a visual sensor are arranged on an actuating mechanism of the welding equipment, the welding gun and the visual sensor move along with the actuating mechanism, and the relative positions of the welding gun and the visual sensor are kept unchanged, and the welding control system comprises:

The starting point determining module is used for controlling the welding gun to move to an initial position and determining a welding seam starting point of the workpiece by utilizing the visual sensor;

the data acquisition module is used for controlling the welding gun to move towards the welding seam starting point and acquiring welding seam data by utilizing the visual sensor;

the judging module is used for judging whether the welding seam data acquired by the visual sensor contain a welding seam termination point or not when the moving distance of the welding gun is larger than a preset value;

the operation module is used for generating a welding track from the welding seam starting point to the welding seam ending point according to the welding seam data if the welding seam data acquired by the visual sensor contains the welding seam ending point, and controlling the welding gun to weld the workpiece according to the welding track;

and the correction module is used for generating a trend space straight line according to the actual motion data of the welding gun if the welding seam data acquired by the visual sensor does not contain the welding seam termination point, calculating a correction coordinate point according to the trend space straight line, the welding seam data and a similar triangle rule, and controlling the welding gun to move towards the correction coordinate point until the welding seam data acquired by the visual sensor contains the welding seam termination point.

The welding equipment provided by the embodiment comprises the welding gun and the visual sensor, wherein the welding gun and the visual sensor synchronously move, the visual sensor is utilized to monitor the welding seam of the workpiece in real time, and the welding gun is controlled to execute welding operation based on the detected welding seam data so as to provide guiding information for the tracking of the welding seam. The embodiment also generates a trend space straight line based on the actual movement data of the welding gun, and calculates a correction coordinate point according to the trend space straight line, the welding line data and a similar triangle rule; when the welding gun track has deviation, the correction coordinate point can correct the welding gun into the welding seam area, so that the welding gun is ensured to be arranged in the welding seam area, and meanwhile, the stable welding wire dry extension length is ensured.

Further, the process of generating a trend space straight line by the correction module according to the actual motion data of the welding gun comprises the following steps: selecting a first actual swing track point and a second actual swing track point from the actual motion data of the welding gun; the moment corresponding to the second actual swing track point is later than the moment corresponding to the first actual swing track point; and calculating trend space straight lines corresponding to all motion coordinate points from the first actual swing track point to the second actual swing track point by using a least square straight line fitting algorithm.

Further, the process of calculating the corrected coordinate point by the correction module according to the trend space straight line, the welding line data and the similar triangle rule comprises the following steps: determining a first vertical line passing through the first actual swing track point and perpendicular to the trend space straight line, and setting an intersection point of the first vertical line and the trend space straight line as a first intersection point; determining a second vertical line which passes through the second actual swing track point and is perpendicular to the trend space straight line, and setting an intersection point of the second vertical line and the trend space straight line as a second intersection point; calculating the deviation of the actual groove center point according to the weld joint data, the current swing and the deviation data; calculating a similar triangle rule based on dynamic displacement according to the coordinates of the first intersection point, the coordinates of the second intersection point and the deviation of the center point of the actual groove to obtain motion differential offset of the welding gun in the directions of an X axis, a Y axis and a Z axis; and calculating the corrected coordinate point according to the motion differential offset and the coordinates of the second intersection point.

Further, the process of controlling the welding gun to move towards the corrected coordinate point until the welding seam data collected by the visual sensor contains the welding seam termination point by the correction module comprises the following steps: step 1: controlling the welding gun to move towards the corrected coordinate point, and judging whether the welding seam data acquired by the visual sensor contain the welding seam termination point or not; if yes, judging that the welding seam termination point is contained in the welding seam data acquired by the visual sensor; if not, entering step 2; step 2: re-selecting a first actual swing track point and a new second actual swing track point from the actual motion data of the welding gun; step 3: calculating trend space straight lines corresponding to all motion coordinate points from the first actual swing track point to the second actual swing track point by utilizing a least square space straight line algorithm; step 4: and (3) calculating a new corrected coordinate point according to the trend space straight line, the welding line data acquired by the visual sensor and the similar triangle rule, and entering into the step (1).

Further, the process of calculating the deviation of the center point of the actual groove by the correction module according to the weld data, the current swing and the deviation data comprises the following steps: calculating groove center point deviation according to the welding line data; determining the current swing amplitude according to the swing waveform and the working time of the welding gun; subtracting the current swing and deviation data from the groove center point deviation to obtain an actual groove center point deviation of the actual groove center point deviation in the Y-axis and Z-axis directions; the deviation data comprise deviations of the welding gun and the visual sensor in the Y-axis direction and the Z-axis direction, and the movement direction of the welding gun is the X-axis direction.

Further, the process of judging whether the welding seam data acquired by the visual sensor contains the welding seam termination point by the judging module comprises the following steps: judging whether the welding seam data acquired by the visual sensor contain a welding seam termination point or not according to a system scanning period.

Further, the process of generating the welding track from the welding seam starting point to the welding seam ending point by the operation module according to the welding seam data comprises the following steps: and fitting the welding seam data through a median filtering method to obtain welding seam characteristic points, and calculating the welding seam characteristic points through a least square straight line fitting algorithm to obtain the welding track from the welding seam starting point to the welding seam ending point.

Since the embodiments of the system portion and the embodiments of the method portion correspond to each other, the embodiments of the system portion refer to the description of the embodiments of the method portion, which is not repeated herein.

The present application also provides a storage medium having stored thereon a computer program which, when executed, performs the steps provided by the above embodiments. The storage medium may include: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), a magnetic disk, or an optical disk, or other various media capable of storing program codes.

The application also provides welding equipment, which can comprise a memory and a processor, wherein the memory stores a computer program, and the processor can realize the steps provided by the embodiment when the processor calls the computer program in the memory. Of course the welding device may also include various network interfaces, power supplies, etc.

In the description, each embodiment is described in a progressive manner, and each embodiment is mainly described by the differences from other embodiments, so that the same similar parts among the embodiments are mutually referred. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant points refer to the description of the method section. It should be noted that it will be apparent to those skilled in the art that various modifications and adaptations of the application can be made without departing from the principles of the application and these modifications and adaptations are intended to be within the scope of the application as defined in the following claims.

It should also be noted that in this specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

Claims (8)

1. A welding control method, characterized in that the method is applied to a welding device, a welding gun and a vision sensor are arranged on an actuating mechanism of the welding device, the welding gun and the vision sensor move along with the actuating mechanism, and the relative positions of the welding gun and the vision sensor are kept unchanged, the welding control method comprises:

controlling the welding gun to move to an initial position, and determining a welding seam starting point of the workpiece by utilizing the visual sensor;

Controlling the welding gun to move towards the welding seam starting point, and acquiring welding seam data by utilizing the visual sensor;

When the moving distance of the welding gun is larger than a preset value, judging whether the welding seam data acquired by the visual sensor contain a welding seam termination point or not;

if yes, generating a welding track from the welding seam starting point to the welding seam ending point according to the welding seam data, and controlling the welding gun to weld the workpiece according to the welding track;

If not, generating a trend space straight line according to the actual motion data of the welding gun, calculating a corrected coordinate point according to the trend space straight line, the welding line data and a similar triangle rule, and controlling the welding gun to move towards the corrected coordinate point until the welding line data acquired by the vision sensor contains the welding line termination point;

generating a trend space straight line according to the actual motion data of the welding gun, wherein the trend space straight line comprises the following steps:

Selecting a first actual swing track point and a second actual swing track point from the actual motion data of the welding gun; the moment corresponding to the second actual swing track point is later than the moment corresponding to the first actual swing track point;

calculating trend space straight lines corresponding to all motion coordinate points from the first actual swing track point to the second actual swing track point by using a least square straight line fitting algorithm;

calculating a corrected coordinate point according to the trend space straight line, the welding line data and a similar triangle rule, wherein the method comprises the following steps:

Determining a first vertical line passing through the first actual swing track point and perpendicular to the trend space straight line, and setting an intersection point of the first vertical line and the trend space straight line as a first intersection point;

Determining a second vertical line which passes through the second actual swing track point and is perpendicular to the trend space straight line, and setting an intersection point of the second vertical line and the trend space straight line as a second intersection point;

calculating the deviation of the actual groove center point according to the weld joint data, the current swing and the deviation data;

Calculating a similar triangle rule based on dynamic displacement according to the coordinates of the first intersection point, the coordinates of the second intersection point and the deviation of the center point of the actual groove to obtain motion differential offset of the welding gun in the directions of an X axis, a Y axis and a Z axis;

And calculating the corrected coordinate point according to the motion differential offset and the coordinates of the second intersection point.

2. The welding control method according to claim 1, wherein controlling the welding gun to move toward the corrected coordinate point until the weld end point is included in the weld data collected by the vision sensor includes:

step 1: controlling the welding gun to move towards the corrected coordinate point, and judging whether the welding seam data acquired by the visual sensor contain the welding seam termination point or not; if yes, judging that the welding seam termination point is contained in the welding seam data acquired by the visual sensor; if not, entering step 2;

step 2: re-selecting a first actual swing track point and a new second actual swing track point from the actual motion data of the welding gun;

Step 3: calculating trend space straight lines corresponding to all motion coordinate points from the first actual swing track point to the second actual swing track point by utilizing a least square space straight line algorithm;

Step 4: and (3) calculating a new corrected coordinate point according to the trend space straight line, the welding line data acquired by the visual sensor and the similar triangle rule, and entering into the step (1).

3. The welding control method of claim 1, wherein calculating an actual groove center point deviation from the weld data, current swing, and deviation data comprises:

Calculating groove center point deviation according to the welding line data;

Determining the current swing amplitude according to the swing waveform and the working time of the welding gun;

Subtracting the current swing and deviation data from the groove center point deviation to obtain an actual groove center point deviation of the actual groove center point deviation in the Y-axis and Z-axis directions; the deviation data comprise deviations of the welding gun and the visual sensor in the Y-axis direction and the Z-axis direction, and the movement direction of the welding gun is the X-axis direction.

4. The welding control method according to claim 1, wherein determining whether the weld data collected by the visual sensor includes a weld end point comprises:

judging whether the welding seam data acquired by the visual sensor contain a welding seam termination point or not according to a system scanning period.

5. The welding control method according to claim 1, wherein generating a welding trajectory from the weld start point to the weld end point from the weld data comprises:

And fitting the welding seam data through a median filtering method to obtain welding seam characteristic points, and calculating the welding seam characteristic points through a least square straight line fitting algorithm to obtain the welding track from the welding seam starting point to the welding seam ending point.

6. A welding control system, characterized in that it is applied to welding equipment, be provided with welder and vision sensor on the actuating mechanism of welding equipment, welder with vision sensor moves along with actuating mechanism, and welder with vision sensor's relative position remains unchanged, welding control system includes:

The starting point determining module is used for controlling the welding gun to move to an initial position and determining a welding seam starting point of the workpiece by utilizing the visual sensor;

the data acquisition module is used for controlling the welding gun to move towards the welding seam starting point and acquiring welding seam data by utilizing the visual sensor;

the judging module is used for judging whether the welding seam data acquired by the visual sensor contain a welding seam termination point or not when the moving distance of the welding gun is larger than a preset value;

the operation module is used for generating a welding track from the welding seam starting point to the welding seam ending point according to the welding seam data if the welding seam data acquired by the visual sensor contains the welding seam ending point, and controlling the welding gun to weld the workpiece according to the welding track;

The correction module is used for generating a trend space straight line according to the actual motion data of the welding gun if the welding seam data acquired by the visual sensor does not contain the welding seam termination point, calculating a correction coordinate point according to the trend space straight line, the welding seam data and a similar triangle rule, and controlling the welding gun to move towards the correction coordinate point until the welding seam data acquired by the visual sensor contains the welding seam termination point;

The process of generating a trend space straight line by the correction module according to the actual motion data of the welding gun comprises the following steps: selecting a first actual swing track point and a second actual swing track point from the actual motion data of the welding gun; the moment corresponding to the second actual swing track point is later than the moment corresponding to the first actual swing track point; calculating trend space straight lines corresponding to all motion coordinate points from the first actual swing track point to the second actual swing track point by using a least square straight line fitting algorithm;

The process of calculating the corrected coordinate point by the correction module according to the trend space straight line, the welding line data and the similar triangle rule comprises the following steps: determining a first vertical line passing through the first actual swing track point and perpendicular to the trend space straight line, and setting an intersection point of the first vertical line and the trend space straight line as a first intersection point; determining a second vertical line which passes through the second actual swing track point and is perpendicular to the trend space straight line, and setting an intersection point of the second vertical line and the trend space straight line as a second intersection point; calculating the deviation of the actual groove center point according to the weld joint data, the current swing and the deviation data; calculating a similar triangle rule based on dynamic displacement according to the coordinates of the first intersection point, the coordinates of the second intersection point and the deviation of the center point of the actual groove to obtain motion differential offset of the welding gun in the directions of an X axis, a Y axis and a Z axis; and calculating the corrected coordinate point according to the motion differential offset and the coordinates of the second intersection point.

7. A welding apparatus comprising an actuator, a memory and a processor, wherein the actuator is provided with a welding gun and a vision sensor, the welding gun and the vision sensor move with the actuator, and the relative positions of the welding gun and the vision sensor remain unchanged, the memory stores a computer program, and the processor when invoking the computer program in the memory implements the steps of the welding control method according to any one of claims 1 to 5.

8. A storage medium having stored therein computer executable instructions which when loaded and executed by a processor perform the steps of the welding control method of any one of claims 1 to 5.