阅读说明：本技术 一种焊接跟踪装置及其跟踪方法 (Welding tracking device and tracking method thereof ) 是由 陆璐 朱维金 钟立明 于 2021-09-24 设计创作，主要内容包括：本发明涉及一种焊接跟踪装置及其跟踪方法,在焊枪喷嘴外表面设有电容阵列,所述电容阵列中的电容呈行列分布；各行电容等间距设置,每行电容为多个,沿焊枪喷嘴外表面圆周方向均匀分布；各行电容一一对应,每列电容之间的连线与焊枪喷嘴轴向中心线平行。本发明的电容式传感器结构简单,易于制造和保证高的精度,可以做得非常小巧,以实现某些特殊的测量；能工作在高温,强辐射及强磁场等恶劣的环境中,可以承受很大的温度变化,承受高压力,高冲击,过载等；能测量超高温和低压差,也能对带磁工作进行测量。(The invention relates to a welding tracking device and a tracking method thereof.A capacitor array is arranged on the outer surface of a welding gun nozzle, and capacitors in the capacitor array are distributed in rows and columns; the capacitors in each row are arranged at equal intervals, and a plurality of capacitors in each row are uniformly distributed along the circumferential direction of the outer surface of the welding gun nozzle; the capacitors in each row correspond to each other one by one, and the connecting line between the capacitors in each row is parallel to the axial central line of the nozzle of the welding gun. The capacitance type sensor has simple structure, is easy to manufacture and ensures high precision, and can be made very small and exquisite to realize some special measurements; the device can work in severe environments such as high temperature, strong radiation, strong magnetic field and the like, can bear great temperature change, high pressure, high impact, overload and the like; the device can measure ultrahigh temperature and low pressure difference and can also measure the magnetic work.)

1. A welding tracking device is characterized in that a capacitor array is arranged on the outer surface of a welding gun nozzle, and capacitors in the capacitor array are distributed in rows and columns;

the capacitors in each row are arranged at equal intervals, and a plurality of capacitors in each row are uniformly distributed along the circumferential direction of the outer surface of the welding gun nozzle;

the capacitors in each row correspond to each other one by one, and the connecting line between the capacitors in each row is parallel to the axial central line of the nozzle of the welding gun.

2. The weld tracking device of claim 1, wherein a spacing is provided between any two adjacent capacitors for each row of capacitors, and wherein the spacing is equal.

3. The weld tracking device of claim 1, wherein each capacitor is coupled to the capacitor controller for feeding back measured capacitor charge values to the robot controller.

4. A weld tracking method, comprising the steps of:

acquiring the position of each capacitor relative to the workpiece through the capacitor array, and screening out a certain row of capacitors as a detection capacitor set at the current moment;

selecting a median from the position serial numbers of all capacitors in the row in the detection capacitor group at the current moment to obtain a capacitor corresponding to the median, and taking the capacitor as the detection capacitor at the current moment;

and measuring the distance between the detection capacitor and the workpiece through the detection capacitor at the current moment, obtaining the current position of the tail end of the welding gun nozzle according to the position relation between the detection capacitor and the welding gun nozzle, and tracking the welding of the welding seam in real time according to the current position and the posture of the tail end of the welding gun nozzle.

5. The weld tracking method of claim 4, wherein the position of each capacitor relative to the workpiece is obtained by:

relative dielectric constant, S is the area of the capacitor plate, d is the vertical distance between the geometric center point of the capacitor patch and the outer surface of the workpiece and the end of the welding gun nozzle, and k is the electrostatic forceAmount of the compound (A).

6. The welding tracking method of claim 4, wherein the step of screening out a certain list of capacitors as the detected capacitor set at the current time comprises the steps of:

acquiring a coordinate matrix A of a workpiece position point on a workpiece closest to the tail end of a welding gun nozzle;

obtaining a coordinate matrix B of each capacitor in each row according to the posture of the welding gun and the relative position of the capacitor on the welding gun nozzle;

the coordinate matrix B and the coordinate matrix A are subjected to numerical difference to obtain the distance between each capacitor in each row and the workpiece;

and selecting a certain column of capacitors corresponding to the minimum value difference as the detection capacitor group at the current moment by a bubble sorting method for all the value differences.

7. The weld tracking method of claim 4, wherein the torch tip attitude is obtained by:

wherein alpha is a working angle and represents an angle formed by two edges which take the geometric center of the current detection capacitor patch as an origin and pass through the origin, one edge takes the origin as the origin and is parallel to the axial center line of the welding gun nozzle, and the other edge is a perpendicular line passing through the origin on a horizontal plane; a ninth distance 9 is a distance between the original point of the geometric center of the currently detected capacitor patch and a projection point of the geometric center point of the auxiliary measurement capacitor patch on the bottom plate, a tenth distance 10 is a distance between the geometric center point of the auxiliary measurement capacitor patch and the bottom plate, an eleventh distance 11 is a distance between the geometric center of the currently detected capacitor patch and the geometric center point of the auxiliary measurement capacitor patch, and a twelfth distance 12 is a distance between the geometric center point of the auxiliary measurement capacitor patch and the bottom plate;

wherein, beta is a walking angle and represents an angle formed by two edges which take the current detected capacitance as an original point and pass through the original point, one edge takes the original point as a starting point and is parallel to the axial central line of the nozzle of the welding gun, and the other edge is a ray which is vertical to the current welding advancing direction; a fourteenth distance 14 is a distance between the geometric center point of the auxiliary measurement capacitor patch and the vertical plate in a direction perpendicular to the current welding advancing direction; a sixteenth distance 16 is a distance between the geometric center point of the current detection capacitor and the geometric center point of the auxiliary measurement capacitor patch; the thirteenth distance 13 is a projection length of the sixteenth distance 16 on a straight line perpendicular to the current welding advancing direction; a fifteenth distance 15 is a ray which takes the geometric center point of the current detection capacitor patch as an origin and is vertical to the current welding advancing direction, and the sum of a fourteenth distance 14 and a thirteenth distance 13 is subtracted from the distance from the vertical plate;

the bottom plate is a plane plate which is used for being welded with the vertical plate and is arranged on the horizontal plane;

the auxiliary measurement capacitor is a certain capacitor which is in the same column with the current detection capacitor, and the capacitor which is closest to the tail end of the welding gun nozzle is eliminated.

8. The weld tracking method of claim 6, wherein the workpiece location points are location points on a riser.

9. The weld tracking method of claim 7, wherein the walking angle β is modified by:

horizontally projecting the geometric center point D of the auxiliary measurement capacitor patch and the geometric center point E of the current detection capacitor to a vertical plate of the workpiece to respectively obtain a starting point and an end point of a section of curve on the outer surface of the workpiece;

performing calculus operation on the starting point and the end point of the curve to obtain a thirteenth distance 13 calculated value;

and subtracting the calculated value of the thirteenth distance 13 from the walking angle beta to obtain the corrected walking angle beta.

Technical Field

The invention belongs to the technical field of welding, and particularly relates to a welding tracking device and a tracking method thereof.

Background

Welding is a material connection technology, separated materials are connected together by generating atomic or intermolecular force through a certain physical and chemical process, the application of the welding technology in production is gradually widened along with the continuous development of the welding technology, the welding technology becomes an important processing means so far, the research of an automatic weld joint tracking system is an important aspect of the welding field, and the automatic weld joint tracking is required for accurate automatic welding. With the large-scale and high-parameter of modern industry, the robot welding technology is fully embodied. The welding robot technique can weld quality due to comparison with conventional arc welding. The robot welding process is relatively complex, the requirements on the processing of grooves and the assembly precision of workpieces are high, and the influence of multiple factors such as deformation generated by heating in the welding process causes certain deviation between the actual welding seam track and the welding seam track, so that the welding quality cannot be guaranteed.

The robot automatically welds the seam tracking, in order to guarantee that the actual seam trajectory is identical with the seam welding trajectory, make the welding quality guaranteed. The robot welding line track automatic correction and compensation device has direct influence on the stability and the welding quality of the welding process, realizes automatic correction and compensation of the welding line track of the robot, reduces the preprocessing cost and precision of a welding part, and improves the process adaptability of the welding process.

The method that the intelligent welding tracking system on the existing market adopts to welding is according to the real-time data that goes out of feedback module, carries out the judgement position of welding seam to control the welding head and weld the welding seam, this kind of real-time welding, the fault-tolerant rate is low, and makes mistakes easily, and efficiency is lower, is unfavorable for whole weldment work's expansion.

Disclosure of Invention

The invention aims to solve the problem that the conventional means such as laser, vision, current and the like are adopted in the automatic welding process of the existing robot, and the real-time performance of welding seam tracking is poor, and the automatic correction and compensation are realized by automatically welding the robot and welding a welding seam track by adopting capacitance tracking.

The technical scheme adopted by the invention for realizing the purpose is as follows: a welding tracking device is characterized in that a capacitor array is arranged on the outer surface of a welding gun nozzle, and capacitors in the capacitor array are distributed in rows and columns;

the capacitors in each row are arranged at equal intervals, and a plurality of capacitors in each row are uniformly distributed along the circumferential direction of the outer surface of the welding gun nozzle; the capacitors in each row correspond to each other one by one, and the connecting line between the capacitors in each row is parallel to the axial central line of the nozzle of the welding gun.

For each row of capacitors, a distance is arranged between any two adjacent capacitors, and the distances are equal.

Each capacitor is connected with the capacitor controller and used for feeding back the measured capacitor charge value to the robot controller.

A weld tracking method comprising the steps of:

acquiring the position of each capacitor relative to the workpiece through the capacitor array, and screening out a certain row of capacitors as a detection capacitor set at the current moment;

selecting a median from the position serial numbers of all capacitors in the row in the detection capacitor group at the current moment to obtain a capacitor corresponding to the median, and taking the capacitor as the detection capacitor at the current moment;

and measuring the distance between the detection capacitor and the workpiece through the detection capacitor at the current moment, obtaining the current position of the tail end of the welding gun nozzle according to the position relation between the detection capacitor and the welding gun nozzle, and tracking the welding of the welding seam in real time according to the current position and the posture of the tail end of the welding gun nozzle.

The position of each capacitor relative to the workpiece is obtained by:

the relative dielectric constant is, S is the area of a capacitor polar plate, d is the vertical distance between the geometric center point of a capacitor curved surface area and the outer surface of a workpiece, which is closest to the tail end of a welding gun nozzle, and k is the constant of electrostatic force;

the method for screening out a certain column of capacitors as the detection capacitor bank at the current moment comprises the following steps:

acquiring a coordinate matrix A of a workpiece position point on a workpiece closest to the tail end of a welding gun nozzle;

obtaining a coordinate matrix B of each capacitor in each row according to the posture of the welding gun and the relative position of the capacitor on the welding gun nozzle;

the coordinate matrix B and the coordinate matrix A are subjected to numerical difference to obtain the distance between each capacitor in each row and the workpiece;

and selecting a certain column of capacitors corresponding to the minimum value difference as the detection capacitor group at the current moment by a bubble sorting method for all the value differences.

The welding gun nozzle tail end posture is obtained through the following formula:

wherein alpha is a working angle and represents an angle formed by two edges which take the geometric center of the current detection capacitor patch as an origin and pass through the origin, one edge takes the origin as the origin and is parallel to the axial center line of the welding gun nozzle, and the other edge is a perpendicular line passing through the origin on a horizontal plane; a ninth distance 9 is a distance between the original point of the geometric center of the currently detected capacitor patch and a projection point of the geometric center point of the auxiliary measurement capacitor patch on the bottom plate, a tenth distance 10 is a distance between the geometric center point of the auxiliary measurement capacitor patch and the bottom plate, an eleventh distance 11 is a distance between the geometric center of the currently detected capacitor patch and the geometric center point of the auxiliary measurement capacitor patch, and a twelfth distance 12 is a distance between the geometric center point of the auxiliary measurement capacitor patch and the bottom plate;

wherein, beta is a walking angle and represents an angle formed by two edges which take the current detected capacitance as an original point and pass through the original point, one edge takes the original point as a starting point and is parallel to the axial central line of the nozzle of the welding gun, and the other edge is a ray which is vertical to the current welding advancing direction; a fourteenth distance 14 is a distance between the geometric center point of the auxiliary measurement capacitor patch and the vertical plate in a direction perpendicular to the current welding advancing direction; a sixteenth distance 16 is a distance between the geometric center point of the current detection capacitor and the geometric center point of the auxiliary measurement capacitor patch; the thirteenth distance 13 is a projection length of the sixteenth distance 16 on a straight line perpendicular to the current welding advancing direction; a fifteenth distance 15 is a ray which takes the geometric center point of the current detection capacitor patch as an origin and is vertical to the current welding advancing direction, and the sum of a fourteenth distance 14 and a thirteenth distance 13 is subtracted from the distance from the vertical plate;

the bottom plate is a plane plate which is used for being welded with the vertical plate and is arranged on the horizontal plane;

the auxiliary measurement capacitor is a certain capacitor which is in the same column with the current detection capacitor, and the capacitor which is closest to the tail end of the welding gun nozzle is eliminated.

The workpiece position point is a position point on the vertical plate.

The walking angle beta is corrected by the following steps:

horizontally projecting the geometric center point D of the auxiliary measurement capacitor patch and the geometric center point E of the current detection capacitor to a vertical plate of the workpiece to respectively obtain a starting point and an end point of a section of curve on the outer surface of the workpiece;

performing calculus operation on the starting point and the end point of the curve to obtain a thirteenth distance 13 calculated value;

and subtracting the calculated value of the thirteenth distance 13 from the walking angle beta to obtain the corrected walking angle beta.

The invention has the following beneficial effects and advantages:

1) the spatial attitude of the welding seam tracking process can be sensed in real time in the welding process, and the precision and the fault tolerance during welding are improved.

2) Good temperature stability

The capacitance value of the capacitance sensor is generally irrelevant to electrode materials, which is beneficial to selecting materials with low temperature coefficient, and the stability is slightly influenced due to extremely low self heating. The resistance sensor has copper loss and is easy to generate heat and generate null shift.

3) Simple structure

The capacitive sensor has simple structure, is easy to manufacture and ensures high precision, and can be made very small to realize certain special measurement; the device can work in severe environments such as high temperature, strong radiation, strong magnetic field and the like, can bear great temperature change, high pressure, high impact, overload and the like; the device can measure ultrahigh temperature and low pressure difference and can also measure the magnetic work.

4) Good dynamic response

The capacitance sensor has very low electrostatic attraction between the charged electrode plates, very low required action energy, very low weight, very high natural frequency and short dynamic response time, can work at several MHz frequency and is especially suitable for dynamic measurement. And because the dielectric loss is small and the power can be supplied by higher frequency, the working frequency of the system is high. It can be used to measure parameters that change at high speeds.

5) Can be measured in a non-contact manner and has high sensitivity

The vibration or eccentricity of the rotating shaft, the radial clearance of the small ball bearing and the like can be measured in a non-contact manner. When non-contact measurement is employed, the capacitive sensor has an averaging effect, and the influence of workpiece surface roughness and the like on the measurement can be reduced.

6) The measurement stability is high, and the conventional arc tracking is the current tracking of the arc between the tail end of the welding wire and a workpiece. But the wire end is continuously melted to fill the weld pool. The continuous melting of the wire is relatively uniform, but not completely uniform. The rate at which the wire tip is continuously melting affects the tracking accuracy. The invention is the distance between the capacitor plate and the workpiece, thus compared with the prior art, the invention has the advantages of Bayer-Thanks to the influence of the melting speed and the feeding speed of the welding wire.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic diagram of the operation of the present invention;

FIG. 3 is a schematic diagram of working angle tracking;

FIG. 4 is a schematic view of a horizontal layout of a weld;

fig. 5 is a schematic diagram of walking angle tracking.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

As shown in fig. 1 to 5, the welding robot includes a welding robot 1, a bottom plate 2, a vertical plate 3, a welding line 4, a welding wire 5, a welding gun 6, a capacitor patch 7, an eighth distance 8, a ninth distance 9, a tenth distance 10, an eleventh distance 11, a twelfth distance 12, a thirteenth distance 13, a fourteenth distance 14, a fifteenth distance 15, a sixteenth distance 16, a seventeenth distance 17, a working angle α, and a walking angle β.

The layout of the capacitor patches 7 on the welding gun 6 is eighths of the circumferential array of the welding gun, and the length direction of the welding gun is nine linear arrays. The purpose of the plurality of arrays is that the shape of the workpiece has uncertainty due to uncertainty in the welding attitude and position of the welding torch 6 in the vicinity of the workpiece. There can be at least several sets of valid data at any one time. Each capacitor is connected with the capacitor controller and used for feeding back a measured capacitor charge value, analog quantity of the charge value is converted to the robot controller through the analog quantity and digital quantity conversion module, and a generated digital quantity value is used for being effectively compared with a value of an expert system to carry out data in a welding expert database.

As shown in fig. 3 and 5, the position and distance define:

working side view three for the direction of vertical bead extension. The first working point A is the highest paster 7 of the welding gun under the current posture of the welding gun 6, and is opposite to the vertical plate 3, namely a group of length arrays, and the sixth paster 7 is arranged from low to high. Too close temperature drift is not good, and too far detection effect is not good. The shortest distance from the first working point A to the geometric center of the patch of the vertical plate 3 and the workpiece is an eighth distance 8. The second working point B is the lowest patch 7 of the welding gun under the current posture of the welding gun 6, is opposite to the bottom plate 2, is a group of length arrays, and is a second patch 7 from low to high. The third working point C is the lowest patch 7 of the welding gun under the current posture of the welding gun 6, is just opposite to the bottom plate 2, is a group of length arrays, and is as low as the sixth patch 7. The second working point B is a twelfth distance 12 from the geometric center of the patch of the base plate 2 to the closest position of the workpiece. The shortest distance from the third working point C to the geometric center of the patch of the bottom plate 2 to the workpiece is the sum of the ninth distance 9 and the tenth distance 10. The distance between the second operating point B and the third operating point C is an eleventh distance 11.

And the attached view five is vertical to the ground and the extending direction of the parallel welding seams. The fourth working point D is a group of length arrays in which the patches 7 on the welding gun 6 are directly opposite to the vertical plate 3 in the current posture of the welding gun 6, and the third patches 7 are from near to far. The fifth operating point E is the eighth patch 7 from near to far.

The shortest distance from the fourth working point D to the workpiece from the geometric center of the patch of the vertical plate 3 is a seventeenth distance 17. The shortest distance from the patch geometric center of the vertical plate 3 to the workpiece of the fifth working point E is the sum of the thirteenth distance 13, the fourteenth distance 14 and the fifteenth distance 15. The distance between the fourth working point D and the fifth working point E is a sixteenth distance 16.

The eighth distance 8, the ninth distance 9, the tenth distance 10, the eleventh distance 11, the twelfth distance 12, the thirteenth distance 13, the fourteenth distance 14, the fifteenth distance 15, the sixteenth distance 16 and the seventeenth distance 17 are expressed by formulas. The capacitor patch 7 has charges, and the bottom plate 2 and the vertical plate 3 have charges with opposite electrodes. By the following formula:

wherein the content of the first and second substances,is the relative dielectric constant, S is the area directly opposite to the capacitor plate, d is the distance of the capacitor plate, and k is the constant of the electrostatic force.

One end of the welding robot 1 is fixed on the ground, and the other end of the welding robot 1 is provided with a welding gun 6.

The welding gun 6 is specifically a gas shielded welding gun, a welding gun for gas shielded welding of a consumable electrode. The nozzle of the welding gun is insulated by ceramic, and is not easy to burn at high temperature; the current flows through the heat-generating body less, the built-in high-efficiency heat exchanger makes the cooling function of the protective gas fully exerted; the ceramic cover at the front end of the contact tube can prevent the contact tube from being directly radiated by electric arc and the temperature of the contact tube is too high; the front end of the wire feeding hose is soft, so that the phenomenon that the welding wire is bent excessively and the wire feeding is unstable can be prevented.

The welding wire 5, the welding gun 6 and the welding robot 1 realize automatic robot welding.

And the robot automatically welds. The welding method is to use the continuously fed welding wire 5, the bottom plate 2 and the vertical plate 3, and the arc burnt among the workpieces as a heat source, and the gas sprayed out from the torch nozzle is used for protecting the arc for welding.

The shielding gas generally used in the gas metal arc welding is argon, helium, carbon dioxide or a mixture of these. The gas shielded arc welding (internationally called MIG welding) is called as the metal inert gas shielded arc welding when argon or helium is used as the shielding gas; when a mixture of an inert gas and an oxidizing gas (oxygen, carbon dioxide) is used as a shielding gas, or when a mixture of carbon dioxide or carbon dioxide + oxygen is used as a shielding gas, the gas is collectively called as gas metal arc welding (MAG welding internationally).

The gas metal arc welding has the main advantages of being capable of conveniently welding various positions and simultaneously having the advantages of being high in welding speed and high in deposition rate. The gas metal arc welding with consumable electrode active gas can be suitable for welding most of main metals, including carbon steel and alloy steel. The MIG arc welding is suitable for stainless steel, aluminum, magnesium, copper, titanium, pickaxe and nickel alloy. Arc spot welding is also possible with this welding method.

The invention is direct current welding, not alternating current welding. The bottom plate 2 and the vertical plate 3 are lower electrodes, and the nozzle of the welding gun 6 is made of ceramic as an insulator. The outer curved surface of the nozzle of the welding gun 6 is provided with a plurality of capacitor patches 7 which are upper electrodes. The distance between the upper and lower electrodes changes to some extent, so that the capacitance changes. The relationship between the capacitance and the distance between the upper and lower electrodes is nonlinear, and therefore, the output capacitance is nonlinearly compensated by a measuring circuit having a compensation function.

The bottom plate 2 and the vertical plate 3 are lower electrodes. The distances between the electrodes on the external curved surface capacitor patch 7 of the nozzle of the welding gun 6 are shown as eighth distance 8, ninth distance 9, tenth distance 10, eleventh distance 11, twelfth distance 12, thirteenth distance 13, fourteenth distance 14, fifteenth distance 15 and sixteenth distance 16.

The ninth distance 9, the tenth distance 10, the eleventh distance 11, the twelfth distance 12, the thirteenth distance 13, the fourteenth distance 14 and the fifteenth distance 15 can be coupled out of the spatial position and the attitude of the welding gun 6, the bottom plate 2 and the vertical plate 3 through electrical, circuit, mathematics and calculation, so that the real-time tracking of the welding seam is realized. And in the welding process, the robot automatically welds the welding seam and tracks the process state.

The eighth distance 8 maintains a certain range of capacitance values. The welding wire 5 end point maintains stable transverse seam tracking.

The ninth distance 9 maintains a certain range of capacitance values. The welding wire 5 end point maintains high seam tracking stability.

And dividing the ninth distance 9 by the inverse cosine trigonometric function value of the eleventh distance 11 to maintain the welding seam tracking stability of the working angle alpha.

And dividing the thirteenth distance 13 by the sixteenth distance 16 by the inverse cosine trigonometric function value to maintain the weld joint tracking stability of the walking angle beta.

The capacitance tracking process comprises the following steps:

firstly, welding radian, and sensing the position of a corresponding workpiece by the capacitor patch 7. The capacitor patch 7 has charges, and the bottom plate 2 and the vertical plate 3 have charges with opposite electrodes. By the following formula:

ε r is the relative dielectric constant, S is the area directly opposite the capacitor plate, d is the distance of the capacitor plate, and k is the electrostatic force constant.

And secondly, screening data.

And converting according to the posture of the robot controller and a tool coordinate system to obtain that the capacitor patch 7 feels right and appropriate to the selection of the corresponding workpiece.

Selecting a principle one; and is opposite or nearly opposite (oblique pair is not easy to converge because the patch 7 projects integral numerical calculation amount for a space curved surface).

The target is as follows: capacitor patch 7 screens out a group of patches in a circumferential array

1. And inputting data of all the subfunctions and establishing variables.

2. The computer retrieves the coordinate A matrix closest to the welding gun 6 on the theoretical workpiece (the bottom plate 2 or the vertical plate 3).

3. The actual position has deviation, and the deviation is generally solved by arc tracking, and the invention solves the problem by capacitance tracking. The deviation of the actual workpiece from the theoretical workpiece position is determined theoretically and qualitatively by selecting the capacitor patch 7 to be right aligned from the viewpoint of numerical analysis, because the capacitor distance is in the centimeter level and the arc motion is in the millimeter level. The theoretical position is used for qualitative judgment of capacitance patch 7 screening, and the actual error is quantitatively compensated by capacitance measurement and robot motion tracking.

4. The robot 1 has tool coordinates TCP at the current moment.

5. And (3) calculating a single capacitor patch 7 by using a tool coordinate TCP coordinate transformation matrix of the robot 1 at the current moment to obtain a coordinate matrix B.

6. The coordinate matrix B of the capacitor patch 7 and the nearest coordinate matrix A are subjected to numerical difference

7. All the numerical value differences are screened out to be suitable positions by a bubble sorting method, and the function output is returned

Selecting a second principle; one patch is selected from low to high. Too close temperature drift is not good, and too far detection effect is not good.

The measuring position of a single capacitor patch 7 is selected as a median, and two capacitor patches 7 are selected approximately in trisection.

And thirdly, tracking the horizontal position of the welding gun 6 away from the vertical plate 3.

Working side view three for the direction of vertical bead extension. The first working point A is the highest paster 7 of the welding gun under the current posture of the welding gun 6, and is opposite to the vertical plate 3, namely a group of length arrays, and the sixth paster 7 is arranged from low to high. Too close temperature drift is not good, and too far detection effect is not good. The shortest distance from the first working point A to the geometric center of the patch of the vertical plate 3 and the workpiece is an eighth distance 8. The eighth distance 8 stabilizes at a certain range. And (3) compensating the motion of the welding robot 1 when the welding robot is too large or too small. To arrive at the figure five for parallel weld seam extension and perpendicular to the ground. The end of the welding wire 5 is compounded with the position of the process molten pool of the welding seam 4.

Fourthly, the welding gun 6 is away from the bottom plate 2, and the height position is tracked.

The third working point C is the lowest patch 7 of the welding gun under the current posture of the welding gun 6, is just opposite to the bottom plate 2, is a group of length arrays, and is as low as the sixth patch 7. The shortest distance from the third working point C to the geometric center of the patch of the bottom plate 2 to the workpiece is the sum of the ninth distance 9 and the tenth distance 10. The sum of the ninth distance 9 and the tenth distance 10 is stabilized within a certain range. And (3) compensating the motion of the welding robot 1 when the welding robot is too large or too small. A working side view three for a perpendicular weld bead extension direction is reached. The end of the welding wire 5 is compounded with the position of the process molten pool of the welding seam 4.

And fifthly, keeping the welding gun 6 at the working angle alpha for tracking the welding seam and stabilizing the attitude tracking.

And dividing the ninth distance 9 by the inverse cosine trigonometric function value of the eleventh distance 11 to maintain the welding seam tracking stability of the working angle alpha.

The working angle alpha is maintained to be stable in a certain range. And (3) compensating the motion of the welding robot 1 when the welding robot is too large or too small. The welding process angle is maintained in a certain process planning range, and has influence on the formation of a welding seam, and the welding direction and the welding process angle also have certain influence on the observation effect of a welding pool, the size of splashing and the gas protection effect.

And sixthly, maintaining the working angle of the welding gun 6 and maintaining the posture tracking of the walking angle beta.

And dividing the thirteenth distance 13 by the sixteenth distance 16 by the inverse cosine trigonometric function value to maintain the weld joint tracking stability of the walking angle beta.

And maintaining the tracking stability of the welding seam at the walking angle beta within a certain range. And (3) compensating the motion of the welding robot 1 when the welding robot is too large or too small. The welding process angle is maintained in a certain process planning range, and has influence on the formation of a welding seam, and the welding direction and the welding process angle also have certain influence on the observation effect of a welding pool, the size of splashing and the gas protection effect.

Seventh step, correcting engineering value and theoretical value of walking angle

From an engineering perspective, the current detected capacitance is the sum of the thirteenth distance 13, the fourteenth distance 14 and the fifteenth distance 15 measured as the distance between the origin and the vertical plate. Where the thirteenth distance 13 is a source of error between theoretical and engineering values. Which is generated in relation to the profile of the riser. The value can be compensated by off-line programming techniques and robot kinematics techniques.

As shown in fig. 3, the point D and the point E are obtained by the robot kinematics technique, and the point D and the point E are projected horizontally to the left workpiece, and the starting point and the ending point of a segment of curve in the height direction of the outer surface of the workpiece are obtained.

By the robot off-line programming technology, the starting point and the ending point of a section of curve in the height direction of the outer surface of the workpiece are subjected to calculus operation, and the thirteenth distance 13 can be obtained.

The thirteenth distance 13 is omitted for the walking angle engineering, so that the walking angle closer to the theoretical value can be obtained.