Welding pipe control method based on planetary gear type automatic control welding torch

Abstract

The present invention discloses a welding pipe control method based on a planetary gear type automatic control welding torch, which includes the following steps: Step 1: Use a CCD camera to collect the image at the preprocessing moment, and feed the collected image back to the control device to calculate ∠POP1 and ∠POP2; Step 2: Establish a coordinate system by using the method of analytic geometry; Step 3: Solve the equation relationship between the pipeline and the camera track, obtain the polar coordinates of point P, and calculate the sizes of areas S1 and S2 through calculus. Step 4: By comparing the size relationship between S1 and S2, control the electromagnetic clutch, and drive the welding pipe to swing through Link I and Link II, so that S1=S2. The present invention adopts a method combining CCD camera shooting and analytic geometry, and judges the position and angle of the welding torch by solving the ratio of the areas on both sides of the plane optical axis photographed by the CCD camera, ensuring that the welding torch is at the lowest point of the pipeline and ensuring that the welding flux completely covers the nozzle.

Description

Technical Field

[0001] The present invention belongs to the technical field of internal circumferential seam welding of pipelines, and particularly relates to a submerged arc welding device for internal circumferential seams of pipelines based on a planetary wheel type automatic control welding torch. Background Art

[0002] Pipeline transportation is the most important, fastest, most economical and reliable way in oil and gas transportation. It can be used to transport water, crude oil, natural gas, refined oil, etc. It has the advantages of large transportation volume, long distance, safety and low cost, and has developed rapidly in countries all over the world. The pipeline welding environment is harsh and the welding span is large. In addition, the pipeline transportation is developing towards high pressure and large diameter, which puts higher and stricter requirements on the welding of internal circumferential welds of pipelines. The welding method of automatic internal circumferential welds of pipelines has become the key factor restricting the quality of the whole project.

[0003] In the automatic welding of pipelines in industries such as petroleum, chemical industry, natural gas and shipbuilding, the commonly used welding methods include tungsten inert gas welding (TIG), which has good welding quality, high cost and low efficiency, and is generally applied to the welding of important pipelines with small hole diameters and thin thicknesses. Then, for the welding method of the internal circumferential seams of particularly large pipeline workpieces, while requiring high weld quality, fast welding speed and improvement of the composition and properties of the weld metal, the generally commonly used welding methods cannot meet the requirements.

[0004] Patent CN 114952139 A can be fixed in the inner cavity of the pipe pile through its own mechanical structure and can realize automatic or man-machine welding of the internal circumferential seam. And after welding is completed, there is no need for manual entry to take out the internal welding robot. Although it meets some welding requirements and solves the welding operation of some welding equipment entering the narrow inner cavity of the pipe pile, when the welding equipment is driven by the inertia of the pipeline and deviates from the lowest point of the pipeline vertical line, it can only be manually pulled to the lowest point, which greatly increases the danger coefficient of manual labor. Patent CN 113427181 B places the pipeline on a welding wheel rack, a gantry welding rack is arranged above the pipeline, and a liftable first welding torch is installed below the gantry welding rack to realize the welding of the outer circumferential seam of the pipeline. An internal circumferential seam welding machine is arranged on the side of the pipeline, and a second welding torch is installed on the welding arm of the internal circumferential seam welding machine to realize the welding of the internal circumferential seam of the pipeline. It has the advantages of simultaneously carrying out the welding work of the inner and outer circumferential seams, being convenient to use, time-saving and labor-saving. However, the operation of the equipment is relatively complex, the welding quality cannot be guaranteed, and it cannot meet the welding work of small pipelines. Therefore, the applicable environment is limited and it is not conducive to the existing environment.

[0005] Patent CN 113182861 A. The fixed rotating gear of this pipeline welding robot is fixedly connected with a telescopic rod, and a fixed frame capable of providing a fixed space for the welding torch is fixedly connected to the telescopic rod. The fixed rotating gear is rotatably connected to the moving transverse cavity. A fixed horizontal shaft is fixedly connected inside the cylindrical cavity, and the fixed rotating gear is rotatably connected to the fixed horizontal shaft. A plurality of top supporting legs are evenly and fixedly connected to the outer wall of the cylindrical cavity. Although the beneficial effect of this invention is that it can complete the welding of the inner wall of the pipeline and ensure that the pipeline will not break and cause irreversible damage, it can only move in a circle around the inner wall of the pipeline and cannot always remain at the lowest point of the vertical line of the pipeline, and is not applicable to the submerged arc welding work of large workpiece pipelines. From the above three problems of inner circumferential seam welding of pipelines, it can be seen that firstly, the device cannot ensure the welding quality by automatically and intelligently making the welding torch at the lowest point of the vertical line of the pipeline. Secondly, the mechanical structure is too complex and the operation is rather troublesome, making it difficult to guarantee the welding quality and welding efficiency. Finally, the submerged arc welding method cannot be adapted to this, resulting in these devices being unable to weld large and thick pipelines, so it is necessary to combine the submerged arc welding method with an automatic control system to ensure that the welding torch always remains at the lowest point of the pipeline, and at the same time, the structure must be compact to ensure the best welding quality. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention provides a welding pipe control method based on a planetary gear type automatic control welding torch that can ensure the weld quality and can effectively weld larger, thicker, and longer straight and larger diameter inner circumferential welds.

[0007] The technical solution adopted by the present invention is as follows: A welding pipe control method based on a planetary wheel type automatic control welding torch, which is used for welding pipe control based on a planetary wheel type automatic control welding torch. The planetary wheel type automatic control welding torch includes multiple groups of planetary wheel type structures, a welding torch swing control system, a fixing frame, a wire feeding device and a flux recovery system; the fixing frame is a columnar frame structure with an isosceles trapezoid or isosceles triangle cross-section; each group of planetary wheel type structures includes two planetary wheel type structures symmetrically arranged at the bottom of the triangular fixing structure. The planetary wheel type structure includes a planetary carrier, multiple planetary wheels, a sun gear and a ring gear. The multiple planetary wheels are installed on the planetary carrier. The ring gear is an internal gear ring. The multiple planetary wheels are engaged between the ring gear and the sun gear through gear meshing. The sun gear and the planetary carrier are coaxially installed on an electromagnetic clutch; the electromagnetic clutch is installed at the bottom of the fixing frame; the flux recovery system is hinged to the center of the top of the fixing frame and can provide flux and recover flux; the wire feeding device is installed on the flux recovery system and can convey welding wire; the welding torch swing control system includes a welding pipe, a CCD camera, a camera mounting seat, a flux switch and a control device; the welding pipe is L-shaped. One end of the welding pipe is connected to the wire feeding device, and the welding wire passes through the welding pipe and extends out from the contact tip; the contact tip is located at one end of the fixing frame; the camera mounting seat is fixed on the welding pipe. A slider is provided on the camera mounting seat, and the slider is placed on the camera track on the side of the flux recovery system; the CCD camera is installed on the camera mounting seat. The flux outlet of the flux recovery system is communicated with the welding pipe, and the flux switch is arranged on the welding pipe; two-ear round pipes are fixedly installed on the welding pipe. The two ear plates of the two-ear round pipe are respectively hinged to the opposite ends of two connecting rods I. The opposite ends of the two connecting rods I are respectively hinged to one ends of two connecting rods II. The other ends of the two connecting rods II are respectively hinged to the two planetary carriers of a group of planetary wheel type structures; the CCD camera, the electromagnetic clutch and the flux switch are respectively connected to the control device;

[0008] It includes the following steps:

[0009] Step 1: Use the CCD camera to collect the image at the preprocessing moment, and feedback the collected image to the control device to calculate ∠POP1 and ∠POP2; where: Point O is the center of the CCD camera lens, Point P is the intersection point of the normal line of the CCD camera lens and the inner wall of the pipeline, and Points P1 and P2 are the intersection points of the two edge lines of the field of view of the CCD camera lens and the inner wall in the section where the lens is located;

[0010] Step 2: Establish a coordinate system by using the method of analytic geometry;

[0011] Step 3: Solve the equation relationship between the pipeline and the camera track, obtain the polar coordinates of Point P, and calculate the sizes of areas S1 and S2 through calculus; Area S1 is the area of the geometric figure enclosed by POP2 and arc PP2, and area S2 is the area of the geometric figure enclosed by POP1 and arc PP1;

[0012] Step 4: By comparing the magnitudes of S1 and S2, control the electromagnetic clutch, and drive the welded pipe to swing through Link I and Link II, so that S1 = S2.

[0013] In the above-mentioned welded pipe control method based on a planetary gear type automatic control welding torch, when establishing the coordinate system in Step 2, take the center of the camera orbit as the origin, the vertically downward direction as the positive direction of the X-axis, and the horizontal direction as the Y-axis to establish a rectangular coordinate system.

[0014] In the above-mentioned welded pipe control method based on a planetary gear type automatic control welding torch, the specific operation of Step 3 is as follows:

[0015] In the coordinate system established in Step 2), the camera orbit and the pipe radius are r and R respectively, the distance between the centers OO1 is l, O is the center of the camera orbit and also the center of the CCD camera lens, and O1 is the center of the pipe; the swing angle of the CCD camera with the vertical line is θ, the tilt angle of the CCD camera lens plane with the vertical line is α, and β1 and β2 are the angles between OP2 and OP1 and the optical axis OP respectively. The magnitudes of the tilt angles α, β1, and β2 are obtained from the internal structure of the CCD camera;

[0016] It is known that: ∠HOP1 = θ - β2, ∠HOP2 = θ + β1, θ = 90° - α;

[0017] The camera orbit equation is: x 2 +y 2 =r 2 ;

[0018] The pipe equation is: (x + l) 2 +y 2 =R 2 ;

[0019] According to the standard polar coordinate equation: x = ρcosθ; y = ρsinθ,

[0020] We get: The polar coordinate expression of the pipe: (ρcosθ + l) 2 +(ρsinθ) 2 =R 2 ;

[0021] After simplification, the coordinates of point P (θ, ρ) can be obtained, where the expression of ρ is:

[0022] From the calculus calculation of the sector area formula: We get:

[0023] The areas S1 and S2 scanned by the CCD camera:

[0024] In the above-mentioned welded pipe control method based on a planetary gear type automatic control welding torch, the specific operation of Step 4 is as follows:

[0025] When S1 > S2, the center position of the welded pipe is offset to the right of the weld seam. The control device feeds back an electrical signal to the electromagnetic clutch, and drives the welded pipe to push leftward through Link I and Link II until S1 = S2;

[0026] When S1 < S2, the center position of the welded pipe is to the left of the weld seam. The control device feeds back an electrical signal to the electromagnetic clutch, and drives the welded pipe to push rightward through Link I and Link II until S1 = S2;

[0027] When S1 = S2, the center position of the welded pipe does not deviate, and the electromagnetic clutch does not act.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] The present invention adopts a method combining CCD camera shooting and analytical geometry. By solving the ratio of the areas on both sides of the optical axis of the plane photographed by the CCD camera, the position and angle of the welding torch are judged. Then, the data signal is converted into an electrical signal and conducted to the center of the welding control system to act on the left and right connecting rods to achieve precise swinging. Thus, the welding torch always swings within a certain range to ensure that the welding torch is at the lowest point of the pipeline, and at the same time ensure that the welding flux completely covers the contact tip. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a structural diagram of the planetary wheel type automatic control welding torch used in the present invention.

[0031] Figure 2 is an installation structural diagram of the planetary wheel type structure of the planetary wheel type automatic control welding torch used in the present invention.

[0032] Figure 3 is a connection structural diagram of the fixing frame, welding flux recovery system and wire feeding device of the planetary wheel type automatic control welding torch used in the present invention.

[0033] Figure 4 is a structural diagram of the welding flux recovery system and wire feeding device of the planetary wheel type automatic control welding torch used in the present invention.

[0034] Figure 5 is a coordinate system diagram established by the present invention.

[0035] Figure 6 is a control schematic diagram of the present invention.

[0036] In the figure: 1 - planetary gear structure, 2 - welding torch swing control system, 3 - fixing bracket, 4 - flux recovery system, 101 - double-ear round tube, 102 - connecting rod, 103 - planet carrier, 104 - electromagnetic clutch, 105 - internal gear ring, 106 - planetary gear, 107 - sun gear, 201 - flux switch, 202 - camera mounting base, 203 - CCD camera, 204 - welded pipe, 205 - camera track, 206 - lug I, 207 - setscrew, 208 - lug II, 301 - U-shaped plate, 302 - thin plate, 303 - main spindle, 401 - flux leak, 402 - housing, 403 - spiral conveyor rod, 404 - servo motor, 405 - sieve plate, 406 - fan, 407 - L-shaped connecting plate, 408 - hexagonal welding wire baffle, 409 - welding wire, 410 - wire feeding assembly, 411 - flux outlet. Detailed implementation mode

[0037] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0038] As Figure 1-4 shown, the planetary wheel type automatic control welding torch of the present invention for use includes two groups of planetary wheel type structures 1, a welding torch swing control system 2, a fixing bracket 3, a wire feeding device and a flux recovery system 4.

[0039] The fixing bracket 3 is a columnar frame structure with an isosceles trapezoid or isosceles triangle cross-section. As Figure 3 shown, the fixing bracket includes two U-shaped plates 301 and two thin plates 302. The two U-shaped plates 301 are arranged in parallel. The two U-shaped plates are connected by three central axes 303. The central axis 303 is perpendicular to the U-shaped plate 301. Two of the three central axes 303 are respectively arranged at both ends of the U-shaped plate. The two ends of the thin plate 302 are respectively sleeved on the two central axes. The two thin plates 302 are respectively located outside the two U-shaped plates. The other central axis is arranged at the center of the U-shaped plate; both ends of the U-shaped plate are arranged downward. The top of the flux recovery system is hinged to the other central axis through lug I.

[0040] As Figure 2 shown, each group of planetary wheel type structures includes two planetary wheel type structures symmetrically arranged at the bottom of the fixing bracket. The planetary wheel type structure includes a planet carrier 103, four planetary gears 106 (not limited to four, can be more than four, or can also be 2 or 3), a sun gear 107 and an internal gear ring 105. The four planetary gears are installed on the planet carrier 103. The four planetary gears 106 are evenly arranged along the circumferential direction. The internal gear ring 105 is an internal gear ring. The four planetary gears 106 are engaged with the internal gear ring 105 and the sun gear 107 through gear meshing. The sun gear 107 and the planet carrier 103 are coaxially installed on the electromagnetic clutch 104. The electromagnetic clutch is installed on the central axis at the bottom of the fixing bracket. The planet carrier 103 is installed on the central axis at the bottom of the triangular fixing structure.

[0041] The described welding torch swing control system 2 includes a welding pipe 204, a CCD camera 203, a camera mounting base 202, a flux switch 201 and a control device; the welding pipe 204 is L-shaped, one end of the welding pipe 204 is connected to a wire feeding device, a welding wire 409 passes through the welding pipe 204 and extends out from a contact tip, and the contact tip is located at one end of a fixing bracket 3. The camera mounting base 202 is fixed on the welding pipe 204, a slider is provided on the camera mounting base 202, and the slider is placed on an arc-shaped camera track 205 on the side of the flux recovery system 4. The CCD camera 203 is mounted on the camera mounting base 202, and the CCD camera 203 is arranged on the side of the camera mounting base 202 facing away from the flux recovery system 4. A double-ear circular pipe 101 is fixedly mounted on the welding pipe 204, two ear plates of the double-ear circular pipe 101 are respectively hinged to opposite ends of two connecting rods I 102, opposite ends of the two connecting rods I 102 are respectively hinged to one ends of two connecting rods II 108, and the other ends of the two connecting rods II 108 are respectively hinged to two planet carriers of a planetary gear structure. The flux switch 201 is arranged on the welding pipe 204.

[0042] The planetary gear structure 1 drives the same-direction rotation of the gear ring 105 through the rotation of the pipe. The gear ring 107 transmits power to the sun gear 107 and the planet carrier 103 through meshing with the planet gears and the meshing of the planet gears with the sun gear to achieve forward and reverse rotations. Since the sun gear 107 and the planet carrier 103 are respectively coaxially connected to the electromagnetic clutch 104, it realizes the automatic control of the left and right positions of the welding torch through speed regulation and forward and reverse rotations, so that the lowest point of the welding torch is always at the lowest point position of the center of the pipe, ensuring that the flux for submerged arc welding completely covers the contact tip. When the load is unbalanced, it can automatically find the balance position, thereby improving the working stability of the transmission.

[0043] As Figure 4 shown, the described wire feeding device includes a housing, a winding drum 410 and a wire outlet pipe. Hexagonal welding wire baffles 408 are fixed at both ends of the winding drum 410. The housing is of a cylindrical structure, and the winding drum 410 is placed inside the housing for winding the welding wire 409. The wire outlet pipe is communicated with the inner cavity of the housing, and the axis of the wire outlet pipe is perpendicular to the axis of the winding drum. The housing is fixedly hinged to the central axis at the top of the fixing bracket through a lifting lug II 208. The wire outlet pipe is fixedly mounted on the top surface of the flux recovery system 4, and the wire outlet pipe is connected to one end of the welding pipe 204. A set screw 207 is provided on the wire outlet pipe, and the welding wire is clamped and controlled by rotating the set screw 207.

[0044] The described flux recovery system 4 includes a housing 402, a spiral conveyor rod 403, and a servo motor 404. Two chambers are provided inside the housing, namely a storage chamber and a conveying chamber. The conveying chamber is an L-shaped chamber where a horizontal chamber and a vertical chamber are connected. The storage chamber is located above the horizontal chamber. A flux leak 401 is provided on the partition between the storage chamber and the horizontal chamber. The spiral conveyor rod is vertically installed in the vertical chamber of the conveying chamber. The servo motor 404 is installed on the outer wall at the bottom of the housing. The output shaft of the servo motor 404 is connected to the lower end of the spiral conveyor rod 403. A flux outlet 411 is provided at the top of the housing. The top of the housing is hinged to the central axis at the top of the fixed frame through a lifting lug I 206. A recovery chamber is provided on the side of the bottom of the housing 402 facing the wire feeding device. A fan 406 is installed in the recovery chamber. A wire mesh 405 is provided between the recovery chamber and the inner cavity of the housing. An L-shaped connecting plate 407 is installed on the side wall of the recovery chamber facing the wire feeding device. The wire feeding device is supported on the L-shaped connecting plate 407 to ensure the stability of the wire feeding device during the welding swing process.

[0045] The described CCD camera 203, electromagnetic clutch 104, flux switch 201, servo motor 404, and fan 406 are respectively connected to the control device. When the welded pipe 204 is affected by external forces left and right, the camera mounting base 202 swings left and right under the influence of inertia on the CCD camera 203. The CCD camera 203 continuously takes pictures of the pipeline and feeds them back to the control center, which then acts on the electromagnetic clutch to correct the position of the welding torch in real time to ensure that the welding process is always at the lowest point.

[0046] As Figure 6 shown, the present invention includes the following steps:

[0047] Step 1: Use a CCD camera to collect images at the preprocessing moment and feed the collected images back to the control device to calculate ∠POP1 and ∠POP2. Among them: Point 0 is the center of the CCD camera lens, Point P is the intersection of the normal line of the CCD camera lens and the inner wall of the pipeline, and Points P1 and P2 are the intersections of the two edge lines of the field of view of the CCD camera lens with the inner wall in the section where the lens is located.

[0048] Step 2: Establish a coordinate system using the method of analytic geometry. Take the center of the camera orbit as the origin, the vertical downward direction as the positive direction of the X-axis, and the horizontal direction as the Y-axis to establish a rectangular coordinate system. The established coordinate system is as Figure 5 shown.

[0049] Step 3: Solve the equation relationship between the pipeline and the camera orbit, obtain the polar coordinates of Point P, and calculate the sizes of areas S1 and S2 through calculus. Area S1 is the area of the geometric figure enclosed by ∠POP2 and arc PP2, and area S2 is the area of the geometric figure enclosed by ∠POP1 and arc PP1.

[0050] The specific operations are as follows:

[0051] In the coordinate system established in step 2), the camera orbit and the pipe radius are r and R respectively, the distance between the centers OO1 is l, O is the center of the camera orbit and also the center of the CCD camera lens, and O1 is the center of the pipe; the swing angle of the CCD camera with respect to the vertical line is θ, the tilt angle of the CCD camera lens plane with respect to the vertical line is α, and β1 and β2 are the angles between OP2 and OP1 and the optical axis OP respectively. The magnitudes of the tilt angles α, β1, and β2 are obtained from the internal structure of the CCD camera.

[0052] It is known that: ∠HOP1 = θ - β2, ∠HOP2 = θ + β1, and θ = 90° - α;

[0053] The equation of the camera orbit is: x 2 + y 2 = r 2 ;

[0054] The equation of the pipe is: (x + l) 2 + y 2 = R 2 ;

[0055] According to the standard polar coordinate equation: x = ρcosθ; y = ρsinθ,

[0056] We get: The polar coordinate expression of the pipe 5: (ρcosθ + l) 2 + (ρsinθ) 2 = R 2 ;

[0057] Simplifying gives the coordinates (θ, ρ) of point P, where the expression of ρ is:

[0058] From the formula for calculating the sector area by calculus: We get:

[0059] The areas S1 and S2 scanned by the CCD camera:

[0060] Step 4: By comparing the magnitudes of S1 and S2, control the electromagnetic clutch, and drive the welded pipe to swing through link I and link II so that S1 = S2.

[0061] The specific operation is as follows:

[0062] When S1 > S2, the center position of the welded pipe is offset to the right of the weld. The control device feeds an electrical signal back to the electromagnetic clutch, and drives the welded pipe to push to the left through link I and link II until S1 = S2;

[0063] When S1 < S2, the center position of the welded pipe is on the left side of the weld seam. The control device feeds an electrical signal back to the electromagnetic clutch, and drives the welded pipe to push to the right through Link I and Link II until S1 = S2;

[0064] When S1 = S2, the center position of the welded pipe does not deviate, and the electromagnetic clutch does not act.

[0065] The left and right directions here are distinguished by looking directly at the welded pipe.

Claims

1. A method for controlling a welded pipe based on a planetary wheel type automatic control welding torch, which is used for controlling a welded pipe based on a planetary wheel type automatic control welding torch. The planetary wheel type automatic control welding torch includes multiple groups of planetary wheel type structures, a welding torch swing control system, a fixing frame, a wire feeding device and a flux recovery system; the fixing frame is a columnar frame structure with an isosceles trapezoid or isosceles triangle cross-section; each group of planetary wheel type structures includes two planetary wheel type structures symmetrically arranged at the bottom of a triangular fixing structure. The planetary wheel type structure includes a planetary carrier, multiple planetary wheels, a sun gear and a ring gear. The multiple planetary wheels are installed on the planetary carrier. The ring gear is an internal gear ring. The multiple planetary wheels are engaged with the ring gear and the sun gear through a gear meshing method. The sun gear and the planetary carrier are coaxially installed on an electromagnetic clutch; the electromagnetic clutch is installed at the bottom of the fixing frame; the flux recovery system is hinged to the center of the top of the fixing frame and can provide flux and recover flux; the wire feeding device is installed on the flux recovery system and can convey welding wire; the welding torch swing control system includes a welded pipe, a CCD camera, a camera mounting base, a flux switch and a control device; the welded pipe is L-shaped. One end of the welded pipe is connected to the wire feeding device, and the welding wire passes through the welded pipe and extends out from the contact tip; the contact tip is located at one end of the fixing frame; the camera mounting base is fixed on the welded pipe. A slider is provided on the camera mounting base, and the slider is placed on a camera track on the side of the flux recovery system; the CCD camera is installed on the camera mounting base. The flux outlet of the flux recovery system is communicated with the welded pipe, and the flux switch is arranged on the welded pipe; a double-ear round pipe is fixedly installed on the welded pipe. The two ear plates of the double-ear round pipe are respectively hinged to the opposite ends of two connecting rods I. The opposite ends of the two connecting rods I are respectively hinged to one ends of two connecting rods II. The other ends of the two connecting rods II are respectively hinged to the two planetary carriers of a group of planetary wheel type structures; the CCD camera, the electromagnetic clutch and the flux switch are respectively connected to the control device; It includes the following steps: Step 1: Use a CCD camera to collect the image at the preprocessing moment, and feed the collected image back to the control device to calculate ∠POP1 and ∠POP2; where: O Point O is the center of the CCD camera lens. Point P is the intersection point of the normal line of the CCD camera lens and the inner wall of the pipeline. Points P1 and P2 are the intersection points of the two edge lines of the field of view of the CCD camera lens and the inner wall in the section where the lens is located respectively; Step 2: Establish a coordinate system by using the method of analytic geometry; Step 3: Solve the equation relationship between the pipeline and the camera track, obtain the polar coordinates of point P, and calculate the sizes of areas S1 and S2 by means of calculus; Area S1 is the area of the geometric figure enclosed by POP2 and arc PP2. Area S2 is the area of the geometric figure enclosed by POP1 and arc PP1; Step 4: By comparing the size relationship between S1 and S2, control the electromagnetic clutch, and drive the welded pipe to swing through connecting rod I and connecting rod II so that S1 = S2.

2. According to the method for controlling a welded pipe based on a planetary wheel type automatic control welding torch as described in claim 1, when establishing the coordinate system in step 2, take the center of the camera track as the origin, take the vertically downward direction as the positive direction of the X-axis, and establish a rectangular coordinate system with the horizontal direction as the Y-axis.

3. According to the method for controlling a welded pipe based on a planetary wheel type automatic control welding torch as described in claim 1 or 2, the specific operation of step 3 is as follows: In the coordinate system established in step 2), the camera orbit and the pipe radius are r and R respectively, and the distance between the centers OO1 is l. O is the center of the camera orbit and also the center of the CCD camera lens, and O1 is the center of the pipe. The swing angle of the CCD camera with respect to the vertical line is θ, the tilt angle of the CCD camera lens plane with respect to the vertical line is α, and β1 and β2 are the angles between OP2 and OP1 and the optical axis OP respectively. The magnitudes of the tilt angles α, β1, and β2 are obtained from the internal structure of the CCD camera. It is known that: ∠HOP1 = θ - β2, ∠HOP2 = θ + β1, θ = 90° - α; The camera orbit equation is: x 2 + y 2 = r 2 ; The pipeline equation is: (x + l) 2 + y 2 = R 2 ; According to the standard polar coordinate equation: x = ρcosθ; y = ρsinθ, Obtained: Polar coordinate expression of the pipeline: (ρcosθ + l) 2 +(ρsinθ) 2 =R 2 ; Simplification gives the coordinates of point P as (θ, ρ), where the expression for ρ is: The formula for calculating the area of a sector by calculus is: We get: The areas S1 and S2 scanned by the CCD camera:

4. The specific operation of step 4 in the welding pipe control method based on the planetary gear type automatic control welding torch according to claim 3 is as follows: When S1 > S2, the center position of the welding pipe is offset to the right of the weld. The control device feeds an electrical signal back to the electromagnetic clutch, and drives the welding pipe to push to the left through Link I and Link II until S1 = S2; When S1 < S2, the center position of the welding pipe is to the left of the weld. The control device feeds an electrical signal back to the electromagnetic clutch, and drives the welding pipe to push to the right through Link I and Link II until S1 = S2; When S1 = S2, the center position of the welding pipe does not deviate, and the electromagnetic clutch does not act.

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