Underwater multi-wavelength composite laser welding deformation self-adaptive regulation and control device and method

Abstract

The invention discloses an underwater multi-wavelength composite laser welding deformation self-adaptive regulation and control device and method. The device comprises a control system, an underwater multi-wavelength composite laser welding system, a double-optical-fiber-semiconductor laser composite welding head and a deformation monitoring system. The method is characterized in that a double-fiber-semiconductor laser composite welding head outputs a laser beam to act on a weldment, a semiconductor short-wave laser large light spot preheats a material, an optical fiber long-wave laser performs underwater high-energy deep penetration welding, and the stability of a molten pool is enhanced through cooperation of the two. The control system controls the deformed curved surface by adaptively adjusting swinging parameters of the fiber lasers on the two sides, and the parameters are adjusted according to deformation of different degrees to ensure that the height of the deformed median surface is reduced. According to the method, the swing parameters of the optical fiber laser beams are adjusted through underwater multi-wavelength hybrid welding to change the energy distribution characteristics of the near-welding-seam area, real-time optimization of stress deformation in the welding process is achieved, and the problems that after an underwater laser welding structural part is welded, stress concentration and deformation are large, and the welding seam strength is insufficient are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater laser welding, and in particular to an underwater multi-wavelength composite laser welding deformation adaptive control device and method. Background Art

[0002] Underwater laser welding has been widely used to repair and connect damaged components and structures in nuclear power plants or submarine structures. Compared with other underwater welding methods, underwater laser welding has many advantages, such as easy control of heat input and high-precision energy transmission for repaired and welded parts. In any fusion welding, welding seam bending deformation caused by rapid heating and cooling is inevitable and has adverse effects on subsequent assembly processes and service life. Therefore, the laser welding energy control technology applied to underwater laser welding needs further breakthroughs.

[0003] The fiber-semiconductor composite laser welding technology preheats the material through the large spot of the semiconductor short-wavelength laser, melts the material surface, increases the material's absorption rate of the fiber laser, and performs deep melting welding with the infrared laser. The multi-wavelength composite laser beam can achieve different positions such as concentric circles and eccentric circles, which can effectively control the adaptive distribution of the heat source, improve the quality of weld formation, and reduce post-weld deformation.

[0004] During laser oscillating welding, the beam forces the molten pool to be stirred, which is beneficial to refine the weld grains and thus improve the joint quality. In addition, the energy distribution of the oscillating heat source is more uniform, which can effectively alleviate the stress concentration after welding, improve the reliability and safety of welded structural parts, and extend their service life. During underwater laser welding, the oscillation of the beam is beneficial to reduce the temperature gradient of the entire weldment. The underwater cooling and the oscillating effect of the beam jointly reduce the concentrated distribution of heat on the weldment. Therefore, how to give full play to the advantages of multi-wavelength composite lasers, coordinate with the beam oscillation to design an adaptive control device that meets the deformation and joint quality requirements of underwater laser welding, and achieve low deformation and high-strength connection of structural parts, is still a problem that needs to be solved for underwater laser welding structures. Summary of the invention

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: an underwater multi-wavelength composite laser welding deformation adaptive control device, including a control system, an underwater multi-wavelength composite laser welding system, a dual optical fiber-semiconductor laser composite welding head, a deformation monitoring system, a local dry drainage device and a weldment, the control system is connected to the underwater multi-wavelength composite laser welding system and the deformation monitoring system through a signal line, the underwater multi-wavelength composite laser welding system is used to output a composite laser beam, including a semiconductor laser, an optical fiber laser A, an optical fiber laser B, a fixed structure A and a fixed structure B, wherein the semiconductor laser, the optical fiber laser A and the optical fiber laser B are connected to the dual optical fiber-semiconductor laser composite welding head through a transmission optical fiber;

[0006] The dual-fiber-semiconductor laser composite welding head includes a fiber laser head A, a fiber laser head B and a semiconductor laser head, wherein the semiconductor laser head includes a semiconductor laser transmission end, a semiconductor laser collimating lens, a semiconductor laser beam and a confocal lens; the fiber laser head A includes a fiber laser transmission end A, a fiber laser collimating lens A, a reflective lens A, a galvanometer A, a spectroscope A, and a swinging fiber laser beam A; the fiber laser head B includes a fiber laser transmission end B, a fiber laser collimating lens B, a reflective lens B, a galvanometer B, a spectroscope B, and a swinging fiber laser beam B, wherein the fiber laser head A and the semiconductor laser The optical head is assembled at the fixed structure A by bolt connection, and the fiber laser head B and the semiconductor laser head are assembled at the fixed structure B by bolt connection. The fixed structure A is not less than 100mm away from the bottom plane of the semiconductor laser head terminal assembly, and the fixed structure B is not less than 100mm away from the top plane of the semiconductor laser head QBH assembly. The vertical distance between the fixed structure A and the fixed structure B is not less than 150mm. The reflective lens A, reflective lens B, beam splitter lens A and beam splitter lens B are all at an angle of 45° to the horizontal plane and remain unchanged. The swing of the light beam is achieved by the lens deflection of the galvanometer A and the galvanometer B.

[0007] The deformation monitoring system is used for real-time monitoring of the deformation surface of the weldment relative to the entire workbench plane during the welding process, and comprises a displacement sensing device and a workbench, wherein the displacement sensing device is installed inside the workbench base.

[0008] Preferably, mounting components are installed at the edges of the fiber laser collimator lens A, the reflector lens A, the reflector lens B and the fiber laser collimator lens B, and the mounting components include a first fixing ring and a second fixing ring, a retaining ring groove is provided on the surface of the second fixing ring, a retaining ring strip is fixedly installed on the surface of the first fixing ring, the retaining ring strip is clamped with the retaining ring groove, a clamping groove is provided on the inner side surface, a receiving groove is provided inside the retaining ring groove, a reset spring is fixedly installed inside the receiving groove, a clamping strip is fixedly connected to the other end of the reset spring, the clamping strip is clamped and fitted with the clamping groove, suction cups are fixedly installed on the opposite surfaces of the first fixing ring and the second fixing ring, and the suction cups are squeezed and fitted with the lenses, and the fiber laser collimator lens A, the reflector lens A, the reflector lens B and the fiber laser collimator lens B are stably installed in the laser through the mounting component to prevent the laser transmission direction from changing due to the shaking of the lenses, and the clamping structure facilitates the replacement of the lenses to meet different welding requirements.

[0009] Preferably, the semiconductor laser beam passes through the semiconductor laser collimating lens and the confocal lens to act on the surface of the weldment, the swinging fiber laser beam A passes through the fiber laser collimating lens A, the reflecting lens A, the galvanometer A, the beam splitter A and the confocal lens to act on the left side of the circular spot of the semiconductor laser beam, and the swinging fiber laser beam B passes through the fiber laser collimating lens B, the reflecting lens B, the galvanometer B, the beam splitter B and the confocal lens to act on the right side of the circular spot of the semiconductor laser beam.

[0010] Preferably, the wavelength of the semiconductor laser is 915 nm, and the wavelength of the fiber laser is 1064 nm.

[0011] Preferably, when underwater welding begins, the light emission of fiber laser A and fiber laser B is 100ms slower than that of the semiconductor laser. The semiconductor short-wave laser reduces the energy loss caused by the scattering effect of the underwater environment to ensure transmission efficiency. Through the thermal effect of the short-wave laser, the fiber long-wave laser efficiently melts the base material and transfers heat. The coordinated effect of the two prevents excessive cooling from increasing the deformation of the welded structure.

[0012] Preferably, the spot diameter of the semiconductor laser beam when acting on the weld surface is D, the spot diameter of the swinging fiber laser beam A and the swinging fiber laser beam B when acting on the weld surface is d, and D and d satisfy 2d≤D≤3d.

[0013] Preferably, the displacement sensing devices are arranged in 8 rows x 8 columns inside the workbench base, and the displacement sensing devices are interconnected to monitor 64 points on the bottom of the weldment to form a deformation curved surface of the weldment.

[0014] Preferably, there is no interference between the oscillating fiber laser beam A and the oscillating fiber laser beam B in the dual fiber-semiconductor laser composite welding head, and the beam splitter A and the beam splitter B are respectively distributed on the left and right sides inside the dual fiber-semiconductor laser composite welding head.

[0015] Preferably, the deformation monitoring system monitors the displacement of the weldment in real time and reconstructs the deformation surface, and feeds back the deformation surface to the control system. The control system adaptively adjusts the process parameter factor through the trained PSO-BP neural network algorithm model, thereby regulating the deformation surface;

[0016] Taking the swing amplitude D, swing frequency f, and swing spot position S of the fiber laser beam A and the fiber laser beam B as input, and the mid-surface height Z of the deformed surface as output, the objective function of the algorithm model is defined as follows:

[0017] Z=F(m×Di,n×fi,q×Si)i=A,B

[0018] In the objective function, the weighting factors are \(m = 0.3\), \(n = 0.2\), and \(q = 0.5\). The update strategy of the objective function \(Z\) is as follows: When \(Z(t + 1)<Z(t)\), continue welding according to \(D\), \(f\), and \(S\) at time \(t + 1\). When \(Z(t + 1)>Z(t)\), modify the values of \(S\), \(D\), and \(f\) one by one according to the magnitude of the input parameter weighting factor based on the trained PSO - BP neural network algorithm model until \(Z(t + 1)<Z(t)\).

[0019] The present invention also provides a method for adaptive control of underwater multi - wavelength composite laser welding deformation, which uses an underwater multi - wavelength composite laser welding deformation adaptive control device and includes the following steps:

[0020] Step 1: Before welding, polish the surface of the welded part with metallographic sandpaper, then soak and clean it with absolute ethanol at room temperature, and then place it on the bottom plate in the water tank and clamp it;

[0021] Step 2: Adjust the position of the double - fiber - semiconductor laser composite welding head according to the weld position, and set the power of the oscillating fiber laser on both sides, the power of the semiconductor laser, the oscillation frequency, the spot position \(S\) of the oscillating fiber laser beam, the oscillation trajectory, and the welding speed through the control system according to the thickness of the welded part;

[0022] Step 3: The control system turns on the semiconductor laser, the oscillating fiber laser A, and the oscillating fiber laser B. Before starting the underwater laser welding operation, stay at the welding starting point for 10 s and keep high - pressure air and argon flowing in to drain the water and form a relatively stable protection environment;

[0023] Step 4: During the welding process, the deformation monitoring system monitors the deformation amount of the welded part in real time and feeds it back to the control system. The control system extracts the height \(Z\) of the median surface of the deformation surface and dynamically adjusts the parameters according to the value of \(Z\), including: the swing amplitude \(D\) of the fiber laser beam A and the fiber laser beam B, the swing frequency \(f\), and the spot position \(S\) of the oscillating fiber laser beam. Modify \(S\), \(D\), and \(f\) one by one according to the magnitude of the input parameter weighting factor based on the trained PSO - BP neural network algorithm model to ensure that \(Z(t + 1)<Z(t)\) and ensure that the deformation amount is controlled within the threshold range to complete the welding. The beneficial effects of this application compared with the prior art are:

[0024] The underwater multi-wavelength composite laser welding deformation adaptive control device and method provided by the present invention include a control system, an underwater multi-wavelength composite laser welding system, a dual-fiber-semiconductor laser composite welding head, a deformation monitoring system, etc., which can solve the problems of stress concentration after welding, large deformation amplitude of thin plate welding, insufficient performance of welding joints, unstable processing quality, etc. in the existing underwater laser welding technology, and the control has a high degree of integration and good operability. The composite between multi-wavelength lasers can improve welding efficiency and weld quality, monitor the deformed surface in real time, and adjust the swing amplitude, swing frequency and swing fiber laser beam spot position of the fiber laser on both sides; ensure the position of the semiconductor laser beam, and greatly improve the adaptive control of underwater laser welding on welding deformation of different plates by adjusting the swing parameters of the fiber laser beam on both sides, which is of great significance to the realization of efficient and high-quality welding of underwater laser welded structural parts.

[0025] The present invention provides an underwater multi-wavelength composite laser welding deformation adaptive control device. It has the following beneficial effects:

[0026] The underwater multi-wavelength composite laser welding deformation adaptive control device and method provided by the present invention include a control system, an underwater multi-wavelength composite laser welding system, a dual-fiber-semiconductor laser composite welding head, a deformation monitoring system, etc., which can solve the problems of stress concentration after welding, large deformation amplitude of thin plate welding, insufficient performance of welding joints, unstable processing quality, etc. in the existing underwater laser welding technology, and the control has a high degree of integration and good operability. The composite between multi-wavelength lasers can improve welding efficiency and weld quality, monitor the deformed surface in real time, and adjust the swing amplitude, swing frequency and swing fiber laser beam spot position of the fiber laser on both sides; ensure the position of the semiconductor laser beam, and greatly improve the adaptive control of underwater laser welding on welding deformation of different plates by adjusting the swing parameters of the fiber laser beam on both sides, which is of great significance to the realization of efficient and high-quality welding of underwater laser welded structural parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of an underwater multi-wavelength composite laser welding deformation adaptive control device according to the present invention;

[0028] Figure 2 This is a schematic diagram of a dual optical fiber-semiconductor laser composite welding head of the present invention;

[0029] Figure 3 A schematic diagram of the positions of the dual optical fiber-semiconductor laser beams and the beam travel trajectories of the present invention;

[0030] Figure 4 This is a schematic diagram of the appearance of the installation assembly of the present invention;

[0031] Figure 5 It is a partial cross-sectional view of the installation assembly of the present invention;

[0032] Figure 6 It is an enlarged schematic diagram of part A of the present invention.

[0033] In the figure: 1. control system; 2. underwater multi-wavelength composite laser welding system; 21. fiber laser A; 22. semiconductor laser; 23. fiber laser B; 3. dual fiber-semiconductor laser composite welding head; 31. fiber laser transmission end A; 311. fiber laser collimating lens A; 312. reflective lens A; 313. spectroscopic lens A; 314. swinging fiber laser beam A; 32. semiconductor laser transmission end; 321. semiconductor laser collimating lens; 322. confocal lens; 323. semiconductor laser beam; 33. fiber laser transmission end B; 331. fiber laser collimating lens B; 332. reflective lens Lens B; 333, spectroscopic lens B; 334, oscillating fiber laser beam B; 34, galvanometer A; 35, galvanometer B; 36, fixed structure A; 37, fixed structure B; 38, bottom plane of semiconductor laser head end assembly; 39, top plane of semiconductor laser head QBH assembly; 4, deformation monitoring system; 41, workbench; 42, displacement sensing device; 5, weldment; 6, local dry drainage device; 7, installation assembly; 71, first fixing ring; 72, second fixing ring; 73, retaining ring strip; 74, retaining ring groove; 75, snap-in groove; 76, retaining strip; 77, accommodating groove; 78, reset spring; 79, suction cup. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments of the present invention are provided for the purpose of illustration and description, and are not intended to be exhaustive or to limit the present invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention, and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

[0035] The first embodiment, as Figure 1As shown, the present invention provides a technical solution: an underwater multi-wavelength composite laser welding deformation adaptive control device, comprising an underwater multi-wavelength composite laser welding system 2, a deformation monitoring system 4, and a dual optical fiber-semiconductor laser composite welding head 3 connected to a control system through a signal line, the underwater multi-wavelength composite laser welding system 2 is used to output a composite laser beam, the underwater multi-wavelength composite laser welding system 2 comprises a semiconductor laser 22, an optical fiber laser A21, and an optical fiber laser B, wherein the semiconductor laser 22, the optical fiber laser A21, and the optical fiber laser B are independent of each other and are connected to the dual optical fiber-semiconductor laser composite welding head 3 through a transmission optical fiber, and the semiconductor laser transmission system and the optical fiber laser transmission system can respectively output a parallel semiconductor laser beam 323 and an optical fiber laser beam downward from the dual optical fiber-semiconductor laser composite welding head 3. When underwater welding begins, the light emission of fiber laser A and fiber laser B is 100ms slower than that of semiconductor laser. Semiconductor short-wave laser reduces the energy loss caused by the scattering effect of the underwater environment to ensure transmission efficiency. Through the thermal effect of the short-wave laser, the fiber long-wave laser efficiently melts the parent material and transfers heat. The coordinated action of the two prevents excessive cooling from increasing the deformation of the welded structure. The deformation monitoring system 4 is used to monitor the deformation surface of the weldment 5 relative to the entire plane of the workbench 41 during the welding process in real time, including a displacement sensing device 42 and a workbench 41. The displacement sensing device 42 is installed inside the base of the workbench 41. The displacement sensing device 42 is arranged in 8 rows × 8 columns inside the base of the workbench 41. Each displacement sensing device 42 is interconnected to monitor 64 points at the bottom of the weldment 5 to form a deformation surface of the weldment 5.

[0036] In this embodiment, the laser power that can be output by the semiconductor laser 22 ranges from 0 to 4000 W, and the laser power that can be output by the fiber laser ranges from 0 to 6000 W.

[0037] The second embodiment is based on the first embodiment. Figures 2 to 6As shown, the dual-fiber-semiconductor laser composite welding head 3 includes a fiber laser head A, a fiber laser head B, a semiconductor laser head, a fixed structure A36 and a fixed structure B37, wherein the semiconductor laser head includes a semiconductor laser transmission end 32, a semiconductor laser collimating lens 321, a semiconductor laser beam 323 and a confocal lens 322; the fiber laser head A includes a fiber laser transmission end A31, a fiber laser collimating lens A311, a reflective lens A312, a galvanometer A34, a spectroscope A313, and a swinging fiber laser beam A314; the fiber laser head B includes a fiber laser transmission end B33, a fiber laser collimating lens B331, a reflective lens B332, a galvanometer B35, a spectroscope B333, and a swinging fiber laser beam B334, wherein the fiber laser head A and the semiconductor laser head are assembled at the fixed structure A36 by bolt connection, and the fiber laser head B and the semiconductor laser head are assembled at the fixed structure B37 by bolt connection, and the fixed structure A36 is not less than 100 mm from the bottom plane 38 of the semiconductor laser head end assembly. The fixed structure B37 is not less than 100mm away from the top plane 39 of the semiconductor laser head QBH component, and the vertical distance between the fixed structure A36 and the fixed structure B37 is not less than 150mm. The reflective lens A312, the reflective lens B332, the beam splitter lens A313 and the beam splitter lens B333 are all at an angle of 45° to the horizontal plane and remain unchanged. The beam swing is achieved by the lens deflection of the galvanometer A34 and the galvanometer B35. The semiconductor laser beam 323 passes through the semiconductor laser collimating lens 321 and the co-converging lens 322. The focusing lens 322 acts on the surface of the weldment 5, the swinging fiber laser beam A314 passes through the fiber laser collimating lens A311, the reflecting lens A312, the galvanometer A34, the beam splitter A313 and the confocal lens 322 and acts on the left side of the circular spot of the semiconductor laser beam 323, and the swinging fiber laser beam B334 passes through the fiber laser collimating lens B331, the reflecting lens B332, the galvanometer B35, the beam splitter B333 and the confocal lens 322 and acts on the right side of the circular spot of the semiconductor laser beam 323.

[0038] The edges of the optical fiber laser collimator lens A311, the reflector lens A312, the reflector lens B332 and the optical fiber laser collimator lens B331 are all equipped with mounting components 7, the mounting components 7 include a first fixing ring 71 and a second fixing ring 72, a retaining ring groove 74 is provided on the surface of the second fixing ring 72, a retaining ring strip 73 is fixedly installed on the surface of the first fixing ring 71, the retaining ring strip 73 is clamped with the retaining ring groove 74, a clamping groove 75 is provided on the inner side surface of 73, a receiving groove 77 is provided inside the retaining ring groove 74, and the interior of the receiving groove 77 is fixedly installed There is a return spring 78, and the other end of the return spring 78 is fixedly connected with a clamping strip 76, which is clamped and adapted with the clamping groove 75. The opposite surfaces of the first fixing ring 71 and the second fixing ring 72 are fixedly installed with suction cups 79, which are pressed and adapted with the lens. When the clamping ring strip 73 is inserted into the clamping ring groove 74, the return spring 78 contracts. When the clamping groove 75 reaches the appropriate position, the elastic force of the return spring 78 will push the clamping strip 76, so that the clamping strip 76 is clamped into the clamping groove 75, thereby firmly clamping the first fixing ring 71 and the second fixing ring 72 together. At this time, the suction cup 79 is tightly adsorbed on the lens to achieve stable fixation of the lens, ensure that the lens is stably installed in the laser, and avoid shaking to change the direction of laser transmission. The clamping structure facilitates the replacement of the lens to meet different welding requirements.

[0039] The changes in the spot positions of the fiber laser beams A and B on the surface of the weldment 5 and the changes in the swing trajectories of the beams are achieved through the deflection of the galvanometers A34 and B35. During this process, the reflective lens A312, the beam splitter lens A313, the reflective lens B332, and the beam splitter lens B333 all maintain their original positions.

[0040] The spot diameter of semiconductor laser beam 323 when acting on the surface of weldment 5 is D, and the spot diameter of oscillating fiber laser beam A314 and oscillating fiber laser beam B334 when acting on the surface of weldment 5 is d, and D and d satisfy 2d≤D≤3d.

[0041] There is no interference between the swinging fiber laser beam A314 and the swinging fiber laser beam B334 in the dual fiber-semiconductor laser composite welding head 3, and the beam splitter A313 and the beam splitter B333 are respectively distributed on the left and right sides inside the dual fiber-semiconductor laser composite welding head 3.

[0042] In this embodiment, the weldment 5 is a TC4 titanium alloy flat plate butt joint structure with a size of 300 mm×100 mm×3 mm, wherein 3 mm is the thickness of the plate, 300 mm is the length of the weld, and 100 mm is the width of the weld, without grooves and gaps. In other embodiments, the weld structure can be of other sizes.

[0043] The process parameters of laser welding are as follows: the set power of the semiconductor laser 22 is 1200W, the set powers of the fiber laser A 21 and the fiber laser B are 1600W, the welding speed is 1.8m / min, the center of the fiber laser A spot is to the left of the center of the semiconductor laser spot, the center of the fiber laser B spot is to the right of the center of the semiconductor laser spot, and the swing trajectories of the fiber laser beams A and B are set to be circular. The underwater laser welding is carried out by the combination of the double fiber lasers and the semiconductor laser, and the underwater laser welding with adaptive regulation of the multi-wavelength composite laser energy is completed.

[0044] The transmittance of the semiconductor laser collimating lens 321, the beam splitting lens A 313, the beam splitting lens B 333, and the confocal lens 322 for the semiconductor laser beam 323 with a wavelength of 915nm is 99.99%.

[0045] The transmittance of the fiber laser collimating lens and the confocal lens 322 for the fiber laser beam with a wavelength of 1064nm is 99.99%.

[0046] The reflectivity of the fiber laser reflection lens and the beam splitting lens for the fiber laser beam with a wavelength of 1064nm is 99.9%.

[0047] During the welding process, the deformation displacement monitoring system monitors and measures the deformation of the 3mm thick TC4 titanium alloy thin plate in real time and feeds it back to the control system 1. The control system 1 adaptively adjusts the process parameter factors through the trained PSO-BP neural network algorithm model, so as to control the deformation surface;

[0048] Taking the swing amplitude D, swing frequency f, and the spot position S of the swinging fiber laser beam of the fiber laser beam A and the fiber laser beam B as the inputs, and the height Z of the median surface of the deformation surface as the output, the objective function of the algorithm model is defined as follows:

[0049] Z = F(m×Di, n×fi, q×Si) i = A, B

[0050] In the objective function, the weighting factors m = 0.3, n = 0.2, q = 0.5, and the update strategy of the objective function Z is as follows: when Z(t + 1) < Z(t), continue welding according to D, f, S at the (t + 1)th moment; when Z(t + 1) > Z(t), modify the values of S, D, f one by one according to the size of the input parameter weighting factors according to the trained PSO-BP neural network algorithm model until Z(t + 1) < Z(t).

[0051] The magnitude of the weighting factor is associated with the amount of deformation. When the deformation of the TC4 titanium alloy thin plate is small, the control system 1 preferentially regulates the process parameters with smaller weighting factor parameters, and preferentially adjusts the swing amplitude D and the swing frequency f. When the deformation of the TC4 titanium alloy thin plate is large, the control system 1 preferentially regulates the process parameters with larger weighting factor parameters, and preferentially adjusts the position S of the swing fiber laser beam spot.

[0052] An underwater multi-wavelength composite laser welding deformation self-adaptive control method uses an underwater multi-wavelength composite laser welding deformation self-adaptive control device, and includes the following steps:

[0053] Step 1: Before welding, polish the surface of the 3mm TC4 titanium alloy weldment 5 with metallographic sandpaper, then soak and clean it with absolute ethanol at room temperature, and then place it on the bottom plate in the water tank and clamp it.

[0054] Step 2: Adjust the position of the dual fiber-semiconductor laser composite welding head 3 according to the weld position. Through the control system 1, set the swing fiber laser power on both sides to 1600W, the semiconductor laser power to 1200W, the swing frequency f = 60Hz, the center of the swing fiber laser beam spot on both the left and right sides and the center of the semiconductor laser beam 323 spot to be 50μm, the swing trajectory to be circular, and the welding speed to be 1.8m / min.

[0055] Step 3: The control system 1 turns on the semiconductor laser 22, the swing fiber laser A21, and the swing fiber laser B. Before starting the underwater laser welding operation, stay at the welding starting point for 10s and keep high-pressure air and argon flowing in to drain the moisture and form a relatively stable protection environment.

[0056] Step 4: During the welding process, the deformation monitoring system 4 monitors the deformation of the weldment 5 in real time and feeds it back to the control system 1. The control system 1 extracts the height Z of the median surface of the deformation surface, and dynamically adjusts the parameters according to the value of Z, including: the swing amplitude D, the swing frequency f, and the position S of the swing fiber laser beam spot of the fiber laser beam A and the fiber laser beam B. According to the trained PSO-BP neural network algorithm model, modify S, D, and f one by one according to the magnitude of the input parameter weighting factor to ensure that Z(t + 1) < Z(t), so as to ensure that the deformation amount is controlled within the threshold range and complete the welding.

[0057] Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art and related fields without creative efforts shall fall within the protection scope of the present invention. The structures, devices, and operation methods not specifically described and explained in the present invention shall be implemented according to the conventional means in the art without special instructions and limitations.

Claims

1. An underwater multi-wavelength composite laser welding deformation adaptive control device, characterized in that: The invention comprises a control system (1), an underwater multi-wavelength composite laser welding system (2), a dual-fiber-semiconductor laser composite welding head (3), a deformation monitoring system (4), a weldment (5), and a local dry drainage device (6), wherein the control system (1) is connected to the underwater multi-wavelength composite laser welding system (2) and the deformation monitoring system (4) via a signal line; The underwater multi-wavelength composite laser welding system (2) is used to output a composite laser beam, and comprises a fiber laser A (21), a semiconductor laser (22), and a fiber laser B (23), wherein the semiconductor laser (22), the fiber laser A (21), and the fiber laser B (23) are connected to a dual-fiber-semiconductor laser composite welding head (3) via a transmission optical fiber; The dual-fiber-semiconductor laser composite welding head (3) comprises a fiber laser head A, a fiber laser head B, a semiconductor laser head, a fixed structure A (36) and a fixed structure B (37), wherein the semiconductor laser head comprises a semiconductor laser transmission end (32), a semiconductor laser collimating lens (321), a semiconductor laser beam (323) and a confocal lens (322), the fiber laser head A comprises a fiber laser transmission end A (31), a fiber laser collimating lens A (311), a reflective lens A (312), a galvanometer A (34), a spectroscope A (313), and a swinging fiber laser beam A (314), and the fiber laser head B comprises a fiber laser transmission end B (33), a fiber laser collimating lens B (331), a reflective lens B (332), a galvanometer B (35), a spectroscope B (333), a swinging fiber laser beam B (334), wherein the fiber laser head A and the semiconductor laser head are assembled at the fixed structure A (36) by bolt connection, and the fiber laser head B and the semiconductor laser head are assembled at the fixed structure B (37) by bolt connection, the fixed structure A (36) is not less than 100 mm from the bottom plane (38) of the semiconductor laser head end assembly, the fixed structure B (37) is not less than 100 mm from the top plane (39) of the semiconductor laser head QBH assembly, and the vertical distance between the fixed structure A (36) and the fixed structure B (37) is not less than 150 mm, the reflective lens A (312), the reflective lens B (332), the beam splitter lens A (313) and the beam splitter lens B (333) are all at an angle of 45° to the horizontal plane and remain unchanged at all times, and the swing of the light beam is achieved by the lens deflection of the galvanometer A (34) and the galvanometer B (35); The deformation monitoring system (4) is used to monitor in real time the deformation curved surface of the weldment (5) relative to the plane of the entire workbench (41) during the welding process. The deformation monitoring system (4) comprises a displacement sensing device (42) and a workbench (41). The displacement sensing device (42) is installed inside the base of the workbench (41).

2. The underwater multi-wavelength composite laser welding deformation adaptive control device according to claim 1 is characterized in that: The edges of the fiber laser collimator lens A (311), the reflector lens A (312), the reflector lens B (332) and the fiber laser collimator lens B (331) are all installed with a mounting assembly (7), the mounting assembly (7) comprising a first fixing ring (71) and a second fixing ring (72), a retaining ring groove (74) being provided on the surface of the second fixing ring (72), a retaining ring strip (73) being fixedly installed on the surface of the first fixing ring (71), the retaining ring strip (73) being engaged with the retaining ring groove (74) The inner side surface of the (73) is provided with a snap-fit ​​groove (75), the inner surface of the snap ring groove (74) is provided with a receiving groove (77), a reset spring (78) is fixedly installed inside the receiving groove (77), the other end of the reset spring (78) is fixedly connected with a clamping strip (76), the clamping strip (76) is snap-fitted with the snap-fit ​​groove (75), and the opposite surfaces of the first fixing ring (71) and the second fixing ring (72) are fixedly installed with a suction cup (79), and the suction cup (79) is pressed and fitted with the lens.

3. The underwater multi-wavelength composite laser welding deformation adaptive control device according to claim 1 is characterized in that: The semiconductor laser beam (323) acts on the surface of the weldment (5) through the semiconductor laser collimating lens (321) and the confocal lens (322); the swinging fiber laser beam A (314) acts on the left side of the circular light spot of the semiconductor laser beam (323) through the fiber laser collimating lens A (311), the reflecting lens A (312), the galvanometer A (34), the beam splitter A (313) and the confocal lens (322); and the swinging fiber laser beam B (334) acts on the right side of the circular light spot of the semiconductor laser beam (323) through the fiber laser collimating lens B (331), the reflecting lens B (332), the galvanometer B (35), the beam splitter B (333) and the confocal lens (322).

4. The underwater multi-wavelength composite laser welding deformation adaptive control device according to claim 1 is characterized in that: The wavelength of the semiconductor laser beam (323) is 915 nm, and the wavelengths of the oscillating fiber laser beam A (314) and the oscillating fiber laser beam B (334) are 1064 nm.

5. The underwater multi-wavelength composite laser welding deformation adaptive control device according to claim 1 is characterized in that: When underwater welding begins, the optical fiber laser A (21) and the optical fiber laser B (23) emit light 100ms slower than the semiconductor laser (22). The semiconductor short-wave laser reduces the energy loss caused by the scattering effect of the underwater environment to ensure the transmission efficiency. Through the thermal effect of the short-wave laser, the optical fiber long-wave laser melts the parent material efficiently and transfers heat. The coordinated effect of the two prevents excessive cooling from increasing the deformation of the welded structural part.

6. The underwater multi-wavelength composite laser welding deformation adaptive control device according to claim 1 is characterized in that: The spot diameter of the semiconductor laser beam (323) when acting on the surface of the weldment (5) is D, and the spot diameter of the oscillating fiber laser beam A (314) and the oscillating fiber laser beam B (334) when acting on the surface of the weldment (5) is d, and D and d satisfy 2d≤D≤3d.

7. The underwater multi-wavelength composite laser welding deformation adaptive control device according to claim 1 is characterized in that: The displacement sensing devices (42) are arranged in 8 rows×8 columns inside the base of the workbench (41), and the displacement sensing devices (42) are interconnected to monitor 64 points on the bottom of the weldment (5) to form a deformed curved surface of the weldment (5).

8. The underwater multi-wavelength composite laser welding deformation adaptive control device according to claim 1 is characterized in that: There is no interference phenomenon between the swinging fiber laser beam A (314) and the swinging fiber laser beam B (334) in the dual-fiber-semiconductor laser composite welding head (3). The beam splitter A (313) and the beam splitter B (333) are respectively distributed on the left and right sides inside the dual-fiber-semiconductor laser composite welding head (3).

9. An underwater multi-wavelength composite laser welding deformation adaptive control device, characterized in that: During the welding process, the deformation monitoring system (4) monitors the displacement of the welded part (5) in real time and reconstructs the deformed surface, and feeds back the deformed surface to the control system (1). The control system (1) adaptively adjusts the swinging parameters of the swinging fiber laser beam A (314) and the swinging fiber laser beam B (334) through the trained PSO-BP neural network algorithm model, so as to control the deformed surface; Taking the swinging amplitude D, swinging frequency f, and the spot position S of the swinging fiber laser beam of the swinging fiber laser beam A (314) and the swinging fiber laser beam B (334) as inputs, and taking the median surface height Z of the deformed surface as the output, the objective function of the algorithm model is defined as follows: Z = F(m×Di, n×fi, q×Si) i = A, B In the objective function, the weighting factors are m = 0.3, n = 0.2, and q = 0.

5. The update strategy of the objective function Z is as follows: when Z(t + 1) < Z(t), continue welding according to D, f, and S at the (t + 1)th moment; when Z(t + 1) > Z(t), according to the trained PSO-BP neural network algorithm model, modify the values of S, D, and f one by one according to the magnitudes of the input parameter weighting factors until Z(t + 1) < Z(t).

10. An underwater multi-wavelength composite laser welding deformation adaptive control method, characterized in that: Adopting an underwater multi-wavelength composite laser welding deformation adaptive control device according to any one of claims 1-9, comprising the following steps: Step 1: Before welding, polish the surface of the welded part (5) with metallographic sandpaper, then soak and clean it with absolute ethanol at room temperature, and then place it on the bottom plate in the water tank and clamp it; Step 2: Adjust the position of the dual-fiber-semiconductor laser composite welding head (3) according to the weld position, and set the swinging fiber laser power, semiconductor laser power, swinging amplitude D, swinging frequency f, the spot position S of the swinging fiber laser beam, the swinging trajectory, and the welding speed on both sides through the control system (1) according to the thickness of the welded part (5); Step 3: The control system (1) turns on the semiconductor laser (22), the swinging fiber laser A (21), and the swinging fiber laser B (23). Before starting the underwater laser welding operation, stay at the welding starting point for 10 s and keep high-pressure air and argon flowing in to drain the moisture and form a relatively stable protection environment; Step 4: During the welding process, the deformation monitoring system (4) monitors the deformation amount of the welded part (5) in real time and feeds it back to the control system (1). The control system (1) extracts the median surface height Z of the deformed surface and dynamically adjusts the parameters according to the magnitude of the Z value, including: the swing amplitude D, swing frequency f, and the spot position S of the swinging fiber laser beam of the fiber laser beam A and the fiber laser beam B. According to the trained PSO-BP neural network algorithm model, S, D, and f are modified one by one according to the magnitude of the input parameter weighting factor to ensure that Z(t + 1) < Z(t), so as to ensure that the deformation amount is controlled within the threshold range and complete the welding.

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