Method for cooperatively regulating and controlling underwater laser shock peening large light and small light

Abstract

The invention discloses an underwater laser shock peening large and small light cooperative regulation and control method, and belongs to the field of underwater laser shock peening, and the method comprises the steps: transmitting a large light beam through a main laser to achieve large-area rapid peening, and transmitting a small light beam through an auxiliary laser to achieve local fine peening in cooperation with a double-axis galvanometer; a path planning and cooperative control system is combined, a common area and a key micro area are automatically divided according to the shape of a workpiece, a thick line path and a fine path are generated, and synchronous or delayed excitation regulation and control of main and auxiliary light beams are achieved. The method can automatically adjust the beam energy distribution and the incident angle according to different structural characteristics of the workpiece, gives consideration to high efficiency and high precision, remarkably improves the coverage rate and consistency of underwater laser shock peening, effectively improves the surface residual compressive stress of the workpiece, prolongs the fatigue life of the workpiece, and reduces the cost. The method is suitable for strengthening treatment of complex metal components such as aerospace and ocean equipment.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of underwater laser shock peening, and particularly relates to a method for synergistically regulating large and small laser spots in underwater laser shock peening. BACKGROUND

[0002] Laser shock peening (LSP) is a strengthening process that generates a transient high-pressure shock wave on the surface of a material by a high-energy laser pulse, thereby forming a residual compressive stress layer inside the material. This technology can significantly improve the fatigue resistance, corrosion resistance, and crack resistance of metal components, and is widely used in the fields of aerospace, shipbuilding, nuclear power equipment, and ocean engineering. Underwater laser shock peening technology uses water as a confinement medium, which not only effectively enhances the intensity of the shock wave, but also avoids surface ablation, making it an important way to achieve efficient and low-loss strengthening. Existing underwater LSP technology usually uses a single spot laser beam for impact, combined with mechanical scanning or fixed light path to complete large-area surface strengthening. However, in actual engineering, components often have complex curved surfaces, microstructure characteristics, and stress concentration areas, and the single-beam scheme still has great limitations in strengthening coverage, focusing stability, and efficiency balance.

[0003] The current underwater LSP technology mainly has the following problems: First, the strengthening efficiency and local precision are difficult to balance. Large spots can quickly cover large areas, but energy distribution is uneven and focusing deviation often occurs in small or complex parts, resulting in insufficient local strengthening; small spots can achieve precise impact, but it is difficult to efficiently process large-area surfaces, and the overall efficiency is significantly reduced.

[0004] Second, the strengthening quality and consistency are not good. Traditional light paths are prone to energy attenuation and reflection loss during underwater propagation, resulting in unstable local residual compressive stress and limited fatigue life improvement after strengthening.

[0005] Third, the device adaptability and control ability are insufficient. For workpieces with hole edges, welds, corners, and other irregular structures, existing single-beam systems cannot achieve full coverage strengthening, have a high proportion of blind areas, and have low automatic control, making it difficult to meet the collaborative strengthening needs of multi-form components.

[0006] Therefore, there is an urgent need for a laser shock peening method that can synergistically regulate large and small beams in underwater environments, balance efficiency and precision, and have complex structure adaptability. SUMMARY

[0007] To solve the above technical problems, the present application provides a method for synergistically regulating large and small laser spots in underwater laser shock peening, comprising: According to the topography of the workpiece surface area and the strengthening demand, a large-diameter light beam emitted by a main laser and a small-diameter light beam emitted by an auxiliary laser are used to perform collaborative impact strengthening on the workpiece surface in an underwater environment. The main laser is used to achieve large-area rapid strengthening, and the small light beam is reflected by a galvanometer mirror to achieve local fine strengthening. The path planning and collaborative control system generates a main light beam coarse path and a small light beam fine path, and sets a synchronous or delayed excitation relationship between the two light beams, thereby achieving collaborative strengthening regulation and control of ordinary areas and key micro areas of the workpiece.

[0008] Optionally, the diameter of the light beam emitted by the main laser is set to 5-10 mm, and the energy density is controlled in the range of 2-5 GW / cm2, so as to achieve the strengthening coverage of a large-area region per unit time. The diameter of the light beam emitted by the auxiliary laser is set to 0.5-3 mm, and the energy density is controlled in the range of 5-8 GW / cm2, so as to meet the high-energy impact demand of a small region. The laser power is obtained by dividing the pulse energy by the spot area and the pulse time.

[0009] Optionally, the light beam emitted by the main laser is calibrated by a collimation system to form a stable main light beam with a divergence angle of 0.1-0.3 mrad, and then reflected by a fixed mirror to be normally incident on the workpiece surface. The light beam emitted by the auxiliary laser is calibrated by a collimation system to form a stable small light beam with a divergence angle of 0.05-0.15 mrad, and then deflected by a two-axis optical galvanometer mirror.

[0010] Optionally, the two-axis optical galvanometer mirror includes a first galvanometer mirror rotatable around an X-axis and a second galvanometer mirror rotatable around a Y-axis. The rotation angle range of the first galvanometer mirror is -30° to +30°, and the rotation angle range of the second galvanometer mirror is -30° to +30°. According to the target region coordinate information, the X-axis rotation angle α and the Y-axis rotation angle β are set respectively, or are adjusted in real time by a micro motor drive, so as to achieve local strengthening of different angle surfaces.

[0011] Optionally, the path planning and collaborative control system includes a workpiece region identification unit and a trajectory control unit. The workpiece region identification unit obtains workpiece surface topography data based on visual sensing or three-dimensional modeling technology, and divides the workpiece into an ordinary strengthening area and a key micro area through an image gray threshold segmentation algorithm. The gray threshold is set in the range of 100-200 according to the workpiece reflection characteristics, and the trajectory control unit generates a main light beam coarse path and a small light beam fine path according to the region division result.

[0012] Optionally, the line spacing of the main beam coarse path is set to 1-1.5 times the spot diameter to ensure coverage continuity. The line spacing of the small beam fine path is set to 0.5-1 times the spot diameter to ensure the density and uniformity of local area reinforcement. When the main beam completes the general area reinforcement, the small beam performs local tracking scanning along the path of the key micro area.

[0013] Optionally, during the main beam reinforcement process, the energy feedback module is used to monitor the output power of the main laser in real time, and automatic adjustment is performed when the energy deviation exceeds the set threshold, and the energy feedback control accuracy is not less than ±2%. During the auxiliary beam scanning process, the galvanometer angle adjustment speed is controlled in the range of 0.5-2 degrees per millisecond to ensure accurate tracking of the fine path.

[0014] Optionally, after the reinforcement is completed, the reinforcement quality is detected, including: X-ray diffraction method is used to detect the residual stress on the surface of the workpiece; A fatigue testing machine is used to test the fatigue life of the workpiece; A laser displacement sensor is used to measure the focusing error; When the detection result does not meet the preset requirement, the laser parameters or scanning path are adjusted according to the feedback result until the reinforcement effect meets the set standard.

[0015] In another aspect, the present application also provides an electronic device, which includes a memory, a processor, and a computing program stored in the memory and executable on the processor, and the processor implements the method when executing the computing program.

[0016] In another aspect, the present application also provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the method.

[0017] Compared with the prior art, the present application has the following advantages and technical effects: The present application constructs a double-beam cooperative system of a main laser and an auxiliary laser, and combines path planning and dynamic control algorithm to realize efficient coverage of a large beam and local fine reinforcement of a small beam.

[0018] This scheme effectively solves the problems of contradiction between efficiency and accuracy, insufficient reinforcement consistency, and poor adaptability to complex structures in traditional underwater LSP, and significantly improves the reinforcement quality and operation stability of the workpiece.

[0019] Experimental results show that the present invention can increase the residual compressive stress in key micro-areas by 20% to 50%, extend the fatigue life by about 2 times, reduce the energy loss rate to below 5%, and reduce the proportion of the strengthening blind zone to less than 2%, thereby achieving an efficient, precise and controllable underwater laser shock strengthening process. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Fig. 1 This is a schematic diagram of the method flow according to an embodiment of the present invention; Fig. 2 This is a schematic diagram of the system structure according to an embodiment of the present invention.

[0021] Among them, 1. main laser, 2. auxiliary laser, 3. main beam, 4. collimation path, 5. fixed mirror, and 6. biaxial optical galvanometer. Detailed Implementation

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0024] Example 1 like Figs. 1-2 As shown, this embodiment provides a method for underwater laser shock enhancement and coordinated control of large and small beams, including: a laser emission module, a main beam path system, a small beam galvanometer reflection adjustment system, an underwater laser transmission and output window, and a path planning and coordinated scanning control system; The laser emitting module includes two laser emitting sources, namely a main laser 1 and an auxiliary laser 2; the main laser 1 is used to emit a large-diameter laser beam with a spot diameter of [missing information]. Satisfying 5mm≤ ≤10mm, power set to ,and The energy requirement for impact strengthening of a large area of ​​the component surface per unit time must be met, i.e., energy density per unit area: =( × ) / (in impact time, =π×( / 2)² is the large-beam spot area, control in the range of 2-5 GW ; the auxiliary laser (2) is used to emit a small-diameter high-energy laser beam, the spot diameter D2 satisfies 0.5mm≤ ≤3mm, the power is set to , the energy density per unit area =( × ) / (wherein impact time, =π×( / 2)² is the small-beam spot area, control in the range of 5-8 GW , to adapt to the energy demand of the micro area or detail reinforcement area; The main beam path system includes a collimation system and a fixed mirror 5, and the laser beam emitted by the main laser 1 forms a stable main beam 3 after collimation by the collimation system, and the divergence angle of the main beam 3 control in the range of 0.1-0.3 mrad, and then guided to the lower side of the laser head after reflection by the fixed mirror 5, forming an incident light path at a vertical angle with the workpiece surface, and acting on a large area of the underwater workpiece surface; The small-beam galvanometer reflection adjustment system includes a collimation path 4 and a set of double-axis optical galvanometers 6, and the laser beam emitted by the auxiliary laser 2 is collimated after passing through the collimation path 4, and the divergence angle of the collimated laser beam control in the range of 0.05-0.15 mrad, and incident to the double-axis optical galvanometer 6; the double-axis optical galvanometer 6 includes an X-axis galvanometer and a Y-axis galvanometer, the X-axis galvanometer can rotate around the X-axis, and the rotation angle range is -30°≤α≤30°, the Y-axis galvanometer can rotate around the Y-axis, and the rotation angle range is -30°≤β≤30°, by presetting the X-axis galvanometer rotation angle α and the Y-axis galvanometer rotation angle β, or by driving the double-axis optical galvanometer 6 to rotate to adjust the angle, the laser beam is deflected to different angle areas of the underwater workpiece surface, to adapt to the reinforcement demand of different structure workpieces; The underwater laser transmission and light output window includes a sealed cavity and a transparent window, and the main beam 3 and the small beam are output through independent paths and then converge on the workpiece surface through the underwater transparent window, the light transmittance τ of the transparent window is not less than 90%, and the refractive index n satisfies the difference |n- |≤0.05( is the refractive index of water), To reduce laser reflection loss at the window-water interface; all optical components are fixedly installed in a sealed cavity with a waterproof rating of not less than IP68 to meet the requirements of underwater laser propagation and ensure optical path stability and energy consistency. After scanning the coarse-line path of the domain, or within the 3-scan interval delay of the main beam, the fine-line path of the key micro-region is moved to perform local tracking scanning of the key area, with the line spacing of the fine path... Satisfying 0.5 ≤ ≤ Meanwhile, the collaborative trajectory control unit can set the excitation mode of the main laser 1 and the auxiliary laser 2, including synchronous excitation or main / auxiliary beam delayed excitation. The delay time t_delay satisfies 0ms≤t_delay≤100ms. The residual stress distribution on the workpiece surface can be optimized by adjusting the delay time t_delay.

[0025] Furthermore, both the main laser 1 and the auxiliary laser 2 are Q-switched Nd:YAG lasers with a laser wavelength of 1064nm and a pulse width τ_p controlled within the range of 10-50ns to ensure the generation of high-amplitude shock waves during laser shock enhancement.

[0026] Furthermore, the reflective surfaces of both the fixed reflector 5 and the biaxial optical galvanometer 6 are coated with a high-reflectivity film. The reflectivity of the film for 1064nm wavelength laser is not less than 99%, so as to reduce the loss of laser energy during the reflection process.

[0027] Furthermore, the sealed cavity is made of stainless steel, and the cavity wall thickness h satisfies 5mm≤h≤10mm to ensure the structural strength and sealing performance of the cavity in the underwater environment.

[0028] Furthermore, the visual sensor in the workpiece area recognition unit adopts an industrial CCD camera with a resolution of no less than 2 million pixels and a frame rate of no less than 30fps to ensure that the workpiece surface image information is acquired quickly and clearly; the three-dimensional modeling technology adopts structured light scanning technology with a scanning accuracy of no less than 0.01mm to accurately acquire the three-dimensional morphology data of the workpiece surface.

[0029] Example 2 like Figs. 1-2 As shown, this embodiment provides a method for coordinated control of large and small beams enhanced by underwater laser shock, including: S1: Device initialization. Check the operating status of the main laser 1, auxiliary laser 2, dual-axis optical galvanometer 6, sealed cavity, and path planning and collaborative scanning control system to ensure normal operation of each component; set the spot diameter of the main laser 1. ,power And pulse width τ_p, set the spot diameter D2 of the auxiliary laser 2, power P2 and pulse width τ_p, set the reflection angle of the fixed mirror 5 to ensure that the main beam 3 is vertically incident to the workpiece surface, set the initial rotation angle α0=0°, β0=0° of the two-axis optical galvanometer 6; S2: Workpiece area recognition, start the workpiece area recognition unit, use the visual sensor to collect the image of the workpiece surface, or use the three-dimensional modeling technology to scan the workpiece surface, obtain the workpiece surface image or three-dimensional topography data; through the image gray threshold segmentation algorithm, set the gray threshold T, process the collected image, divide the workpiece surface into ordinary strengthening area and key micro area, and record the position coordinate information of each area; S3: Collaborative trajectory planning, the collaborative trajectory control unit generates the coarse line path of the main beam 3 and the fine path of the small beam according to the workpiece surface area division result and position coordinate information obtained in step S2, and combines the set main beam 3 line spacing And small beam line spacing , generate the coarse line path of the main beam 3 and the fine path of the small beam; at the same time, according to the workpiece material and strengthening requirements, set the excitation mode of the main beam and the auxiliary beam, if the delay excitation is selected, set the delay time t_delay; S4: Underwater laser shock peening, fix the workpiece on the underwater working platform, so that the workpiece surface is at a predetermined depth H (5mm≤H≤20mm) under water; start the main laser 1, the main beam 3 along the coarse line path planned in step S3 to quickly impact the workpiece surface ordinary strengthening area, and the energy density of the main beam 3 is monitored in real time , ensure Stable in the range of 2-5GW / cm²; S5: Local fine strengthening, after the main beam 3 completes the corresponding area coarse line path scanning, or within the main beam 3 scanning interval delay, according to the set delay time t_delay, start the auxiliary laser 2; adjust the X-axis galvanometer rotation angle α and the Y-axis galvanometer rotation angle β by rotating the micro motor driven two-axis optical galvanometer 6, so that the small beam scans the workpiece surface key micro area along the fine path planned in step S3, and the energy density of the small beam is monitored in real time , ensure Stable in the range of 5-8GW / cm²; S6: Strengthening quality detection and feedback, after the main beam 3 and the small beam complete the whole impact strengthening work, use the residual stress tester to detect the residual stress of the workpiece surface, use the fatigue testing machine to test the fatigue life of the workpiece, and use the laser displacement sensor to detect the focusing error of the workpiece surface; if the residual stress, fatigue life or focusing error does not meet the preset requirements, return to step S1 to adjust the device parameters until the detection results meet the requirements.

[0030] Further, in step S4, when the main beam 3 impinges on the reinforcement, the power of the main laser 1 is adjusted in real time by the energy feedback control module The control accuracy of the energy feedback control module is ±2% to ensure the stability of the energy density .

[0031] Further, in step S5, the angle adjustment speed v_α (X-axis galvanometer angle adjustment speed) and v_β (Y-axis galvanometer angle adjustment speed) of the biaxial optical galvanometer 6 satisfy 0.5° / ms≤ν_α≤2° / ms, 0.5° / ms≤v_β≤2° / ms, to ensure that the small beam can quickly and accurately follow the fine path movement.

[0032] Further, in step S6, the residual stress tester uses the X-ray diffraction method, and the test accuracy is not less than ±5MPa; the loading accuracy of the fatigue testing machine is not less than ±1%; and the measurement accuracy of the laser displacement sensor is not less than ±0.01mm, to ensure the accuracy of the reinforcement quality detection results.

[0033] Taking the underwater reinforcement of a titanium alloy blade (including a φ5mm stress hole and a weld root) of an aero-engine as an example, the steps are implemented as follows: Device initialization: the main laser =8mm, =3GW / cm², ≈50.24W; the auxiliary laser =1.5mm, =6.5GW / cm², ≈8.08W; the water depth H is set to 12mm, and the water temperature is 23℃.

[0034] Region identification: CCD camera + structured light scanning, dividing the blade curved surface general area and the hole edge / weld critical micro-area, and marking the critical area coordinates (accuracy ±0.03mm).

[0035] Trajectory planning: the main beam coarse path =8mm, speed 50mm / s; the auxiliary beam hole edge spiral path =0.8mm, weld "Z" path =1.2mm, speed 30mm / s; the delay excitation t_delay is set to 45ms.

[0036] Reinforcement operation: the main beam scans the general area, and the power is controlled in real time ; the auxiliary beam scans the critical area, and the galvanometer angle is dynamically adjusted (hole edge area α=15°, weld area β=20°).

[0037] Quality detection: the residual compressive stress of the critical area is 410MPa, the fatigue life is prolonged by 2.3 times, and the focusing error is ±0.15mm, all of which meet the requirements.

[0038] In another aspect, the present embodiment also provides an electronic device, comprising a memory, a processor, and a computing program stored in the memory and executable on the processor, wherein the processor implements the method when executing the computing program.

[0039] In another aspect, the present embodiment also provides a computer readable storage medium, which stores a computer program, wherein the computer program is executable by a processor to implement the method.

[0040] The above merely describes preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any changes or replacements within the technical scope disclosed by the present application, which can be easily conceived by those skilled in the art, shall be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method for coordinated control of large and small beams in underwater laser shock enhancement, characterized in that, include: Based on the morphology and strengthening requirements of the workpiece surface area, the large-diameter beam emitted by the main laser and the small-diameter beam emitted by the auxiliary laser are used to perform synergistic impact strengthening of the workpiece surface in an underwater environment. The main laser is used to achieve rapid enhancement over a large area, while the small beam is reflected by a galvanometer to achieve fine enhancement in a localized area. The path planning and collaborative control system generates a coarse path for the main beam and a fine path for the small beam, and sets a synchronous or delayed excitation relationship between the two beams, thereby achieving collaborative enhancement and control of the ordinary area and key micro-area of ​​the workpiece.

2. The method according to claim 1, characterized in that, The main laser emits a beam with a diameter of 5 to 10 millimeters and an energy density controlled within the range of 2 to 5 gigawatts per square centimeter to achieve enhanced coverage of a large area per unit time. The auxiliary laser emits a beam with a diameter of 0.5 to 3 millimeters and an energy density controlled within the range of 5 to 8 gigawatts per square centimeter to meet the high-energy impact requirements of small areas. The laser power is obtained by dividing the pulse energy by the spot area and the pulse time.

3. The method according to claim 1, characterized in that, The beam emitted by the main laser is collimated by a collimation system to form a stable main beam with a divergence angle of 0.1 to 0.3 milliradians, and then reflected by a fixed mirror and incident perpendicularly on the surface of the workpiece. The beam emitted by the auxiliary laser is collimated by a collimation system to form a stable small beam with a divergence angle of 0.05 to 0.15 milliradians, which is then deflected and incident through a biaxial optical galvanometer.

4. The method according to claim 3, characterized in that, The biaxial optical galvanometer includes a first galvanometer that can rotate about the X-axis and a second galvanometer that can rotate about the Y-axis. The rotation angle range of the first galvanometer is from -30 degrees to +30 degrees, and the rotation angle range of the second galvanometer is from -30 degrees to +30 degrees. Based on the coordinate information of the target area, the X-axis rotation angle α and the Y-axis rotation angle β are set respectively, or adjusted in real time by micro motor drive, so as to achieve local strengthening of the surface at different angles.

5. The method according to claim 1, characterized in that, The path planning and collaborative control system includes a workpiece area identification unit and a trajectory control unit; The workpiece area recognition unit acquires workpiece surface morphology data based on visual sensing or 3D modeling technology, and divides the workpiece into ordinary reinforcement area and key micro area through image grayscale threshold segmentation algorithm. The grayscale threshold is set in the range of 100 to 200 according to the workpiece's reflection characteristics. The trajectory control unit generates a coarse path for the main beam and a fine path for the small beam based on the region division results.

6. The method according to claim 3, characterized in that, The spacing between the coarse lines of the main beam is set to 1 to 1.5 times the spot diameter to ensure coverage continuity. The spacing between the lines of the fine path of the small beam is set to 0.5 to 1 times the spot diameter to ensure the density and uniformity of local enhancement. After the main beam completes the enhancement of the general region, the small beam performs local tracking scanning along the path of the key micro-region.

7. The method according to claim 6, characterized in that, During the main beam enhancement process, the output power of the main laser is monitored in real time through the energy feedback module, and automatic adjustment is performed when the energy deviation exceeds the set threshold. The energy feedback control accuracy is not less than ±2%. During the auxiliary beam scanning process, the galvanometer angle adjustment speed is controlled within the range of 0.5 to 2 degrees per millisecond to ensure accurate tracking of the fine path.

8. The method according to claim 1, characterized in that, After the strengthening process is completed, a strengthening quality inspection is performed, including: Residual stress on the workpiece surface was detected using X-ray diffraction. The fatigue life of the workpiece was tested using a fatigue testing machine. Focusing error is measured using a laser displacement sensor; If the test results do not meet the preset requirements, the laser parameters or scanning path are readjusted based on the feedback results until the enhancement effect meets the set standards.

9. An electronic device comprising a memory, a processor, and a computing program stored in the memory and executable on the processor, characterized in that, When the processor executes the computing program, it implements the method of any one of claims 1-8.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the method of any one of claims 1-8.

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