Outer ring ring diameter adjustable underwater laser coaxial fuse repair method and device

Abstract

The application relates to an underwater laser coaxial fuse repairing method and device with adjustable outer ring diameter, and belongs to the technical field of underwater laser repairing. In view of the problem that the fixed cleaning spot cannot meet the actual demand due to the underwater high-humidity environment, a three-level dynamic adjustment mechanism of feedforward, real-time humidity correction and visual fine adjustment is established with the real-time humidity in the cover as a core variable, the cleaning range of the outer ring is adaptively changed, and the systematic blind area of the existing method is eliminated when the stability of the gas phase zone is reduced, and the repairing quality is degraded. The three-level dynamic adjustment of the outer ring diameter covers three main disturbance sources of repairing speed change, interlayer thermal accumulation effect and humidity fluctuation in the gas phase zone, so that the process robustness is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of underwater laser repair technology, specifically to an underwater laser coaxial filament repair method and apparatus with adjustable outer ring diameter. Background Technology

[0002] The repair of underwater metal structural components has long faced challenges due to harsh repair environments and difficulty in ensuring quality. Laser coaxial filament repair technology, with its advantages of controllable heat input, high material utilization, and small heat-affected zone, has gradually been introduced into the field of underwater repair engineering. The underwater laser coaxial filament repair device utilizes an energy-controllable point-ring spot system to shape the laser beam into a composite form of an inner high-energy cladding spot and an outer low-energy cleaning spot. Combined with an inner exhaust chamber and an outer drainage chamber, a local vapor phase protection zone is established on the workpiece surface, providing an effective device foundation for underwater laser filament repair. In this device, the inner spot is responsible for cladding deposition, while the outer annular spot advances synchronously in front of the inner spot, removing the oxide scale from the substrate surface through low-energy laser irradiation, creating a clean bonding interface for the inner cladding.

[0003] However, existing devices and their repair methods have two interrelated methodological defects in engineering practice, and the coupling relationship between these two defects has not yet been recognized or utilized.

[0004] Defect 1: Lack of quantitative monitoring of the gas phase state; its fluctuations, as a latent source of disturbance, are not incorporated into the control system. Current methods rely on a preset fixed flow rate to introduce protective gas into the repair enclosure, without real-time monitoring of the actual humidity and pressure state of the gas phase within the enclosure. In actual underwater repair environments, multiple factors, such as underwater pressure fluctuations, uneven sealing of curved surfaces of components, and changes in the enclosure's posture caused by robotic arm movement, can lead to continuous fluctuations in humidity within the enclosure. When humidity is high, the oxidation rate of the metal surface in the repair area accelerates significantly, and a thicker oxide scale forms on the cladding layer surface in a shorter time. However, the repair process continues, and the operator cannot perceive this change in state, resulting in a silent decline in repair quality. This insidious quality degradation is particularly prominent in high-salt and high-humidity underwater environments, often only being discovered during the non-destructive testing phase after repair, causing significant rework losses.

[0005] Defect 2: The outer ring diameter is fixed, making it unable to adapt to changes in process conditions, and it fails to incorporate the humidity of the gas phase region into the calculation of cleaning requirements. In existing methods, the outer ring diameter is determined by a fixed optical structure and remains unchanged during the repair process. When the repair speed changes at path corners or curved surface transitions, the size of the heat-affected zone changes accordingly. The fixed outer ring size leads to a mismatch between the cleaning range and actual needs—when the speed decreases, the heat-affected zone expands while the cleaning range is insufficient; when the speed increases, the cleaning range becomes redundant while energy is wasted. More importantly, even if an adjustment rule based on the repair speed is established for the outer ring diameter, if the humidity inside the enclosure is not taken into account, when the humidity is too high and the oxidation rate is accelerated, the originally suitable outer ring diameter is actually insufficient, and the cleaning range needs to be expanded accordingly to ensure the cleanliness of the substrate surface before cladding.

[0006] The essential connection between the two aforementioned defects lies in the fact that the humidity state of the gas phase is one of the key environmental variables determining the extent of outer ring cleaning requirements. However, existing methods completely separate the two, neither monitoring the humidity of the gas phase nor establishing any quantitative correlation between it and the outer ring cleaning range, resulting in a systemic blind spot in repair quality control. In the complex underwater environment of high salinity and high humidity, this blind spot has a particularly significant impact on the metallurgical quality of the repair layer, and is one of the core bottlenecks restricting the stability of underwater laser filament repair quality. Summary of the Invention

[0007] The purpose of this invention is to use the real-time humidity of the gas phase region as the core intermediate variable connecting the environmental state and the outer ring cleaning requirements, so as to achieve adaptive matching of the cleaning range to the dual changes of process conditions and environmental state during the underwater laser coaxial filament repair process, thereby fundamentally improving the stability and process robustness of the metallurgical quality of the repair layer.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A method for repairing underwater laser coaxial fuses with adjustable outer ring diameter includes the following steps: S1. The joint criterion for establishing the gas phase zone and confirming the repair permit is used to position the repair device on the surface of the workpiece to be repaired. The gas protection system is activated, and protective gas (usually argon or nitrogen) is introduced into the inlet to purge moisture from the inside of the water shield, establishing the initial gas phase protection zone. A miniature dew point sensor and pressure sensor are integrated into the inner wall of the water shield to collect the relative humidity inside the shield in real time. (%RH) and air pressure (Pa). The system uses the following two conditions as criteria for granting repair permission: in, Set the target protection air pressure value. This is the permissible pressure deviation threshold. This criterion indicates that the water shield is properly sealed, the drainage chamber is functioning normally, and there is no risk of large-scale water ingress.

[0009] in, The set value is 15% RH relative humidity. A value below this threshold indicates that the humidity inside the enclosure has dropped to an acceptable level, the cleanliness of the vapor phase protection zone meets the remediation requirements, and the oxidation rate of the metal surface is within a controllable range.

[0010] In this step, repair permission is granted using a combined criterion rather than a single condition. The system is only allowed to proceed to subsequent repair steps when both the seal integrity criterion and the vapor phase cleanliness criterion are simultaneously met, and the outer ring diameter has been initially set based on the current humidity reading for subsequent steps. This combined criterion binds the confirmation of the vapor phase state and the initialization of the outer ring diameter to the same entry threshold, forcibly establishing a coordinated relationship between the two subsystems from the start of repair, thus avoiding the possibility of them operating independently.

[0011] If the joint criteria are not met within the preset waiting time (usually set to 5 minutes), the system will automatically increase the gas flow rate (to 150% to 200% of the initial flow rate) and trigger an alarm, prompting the operator to check the sealing status. This step should not be skipped to begin the repair process, preventing the repair operation from starting before the gas phase zone is fully established.

[0012] After the gas phase zone is established, the dew point sensor reading is used as feedback, and the protective gas flow rate is continuously and dynamically adjusted through a PI control algorithm to stably maintain the humidity inside the hood within the target range (target value). RH (with ±3%RH adjustment dead zone) enables closed-loop maintenance throughout the gas phase region. The real-time humidity value is continuously output to the outer ring diameter dynamic adjustment module at a frequency of 10Hz, serving as the dynamic input for its correction calculation.

[0013] S2. Initial setting of the outer ring diameter: Based on the thermophysical parameters of the material to be repaired, the preset repair linear velocity, and the current humidity value of the gas phase zone confirmed in step one, calculate the reference value of the outer ring diameter according to the following criteria. : The meanings of each parameter are as follows: The diameter (mm) of the inner circle spot is determined by the optical system of the device; Thermal diffusivity of material (mm) 2 / s), retrieved from the materials database; Repair line speed (mm / s) is determined by path planning; The lead distance (mm) between the outer ring light spot and the inner ring is a fixed setting value, determined by the geometry of the device, and is usually 3 to 8 mm. : Material oxidation sensitivity correction coefficient, retrieved from a pre-set material database, dimensionless. A larger value (typically 1.3–1.6) is used for oxidation-sensitive materials such as titanium alloys (e.g., TC4) and nickel-based superalloys (e.g., Inconel 625 / 718), while a smaller value (typically 0.8–1.0) is used for oxidation-insensitive materials such as low-carbon steels (e.g., Q235, Q345). The dynamic correction function for humidity in the gas phase region is defined as follows: in The humidity sensitivity coefficient (dimensionless) is determined by the material oxidation kinetics and is provided by a database; its typical range is 0.15–0.45.

[0014] The physical meaning of the function is: when When it approaches 0, The outer ring diameter returns to the baseline value under ideal dry conditions; when Approaching hour, The outer ring diameter is correspondingly enlarged. This is multiplied by a factor of 1 to compensate for the amplified effect of increased oxidation rates caused by higher humidity, thus amplifying the cleaning requirements. The function ranges from 0 to... The linear interpolation between them ensures the monotonicity and predictability of the adjustment behavior.

[0015] For sections of the repair path where speed changes occur (such as deceleration at path corners or speed changes at curved transitions), each speed section is identified in advance during the path planning stage and substituted into the corresponding values. Value Calculation This forms a loop feedforward sequence distributed along the path. During execution, the control system automatically switches the corresponding feedforward value according to the current path position, realizing a synchronous feedforward response when the repair speed changes, and avoiding dynamic mismatch of the cleaning range caused by speed changes.

[0016] The outer ring diameter is adjusted via an axial displacement mechanism of the conical lens group in the driving shaping element. The correspondence between the axial displacement of the conical lens group and the outer ring diameter is optically calibrated and written into the lookup table of the control system. After adjustment and locking, a ready signal is output to the repair permission logic in step one, completing the last condition of the joint criterion.

[0017] S3. Idle path verification, substrate pre-cleaning, and physical calibration of feedforward loop diameter: Idle walking is performed according to the preset repair route, with only the outer low-energy laser spot activated (the inner cladding laser is not activated, and the wire is not fed). While completing path geometry verification and substrate pre-cleaning, the loop diameter value calculated in S2 is physically calibrated. During the idle walk, the vision sensor continuously samples the cleaning effect in the outer laser spot's effective area, calculating the measured effective cleaning width for each speed range. (mm), compared to the current Corresponding theoretical cleaning width (Calculated from the optical model) Compare and calculate the calibration deviation: like If a systematic bias exists, then... A comprehensive correction is performed. The standard for determining a systematic deviation is that five or more consecutive sampling points along the path deviate in the same direction, and the absolute value of the average deviation exceeds 0.3 mm. The correction amount is: The corrected value is: by This serves as the first-level ring diameter benchmark for the formal repair phase.

[0018] The significance of this step lies in the parameters of the feedforward formula (especially...). In The values ​​are derived from a materials database, whose parameters are calibrated under standard laboratory conditions, inevitably resulting in deviations from actual underwater operating conditions. The no-load calibration uses the actual cleaning effect to systematically correct this deviation in a single step, ensuring that subsequent repairs are based on a physically verified ring diameter benchmark, rather than entirely relying on calculated values. This effectively reduces the impact of database parameter inaccuracies on repair quality.

[0019] After the empty run is completed, the interval between the end of cleaning and the start of formal repair must be strictly controlled within 120 seconds. If this time limit is exceeded, the system will automatically prompt for a second pre-cleaning to prevent secondary oxidation of the cleaned substrate surface during the waiting period, which could lead to a failure of cleanliness.

[0020] S4. Budgeting and initialization of interlayer outer ring diameter compensation and repair parameters: Retrieve initial repair parameters (laser power, wire feed speed, defocusing amount, track spacing, etc.) from the process database according to the material type and defect depth, and simultaneously budget the interlayer compensation value of the outer ring diameter of each repair layer.

[0021] With the number of repair layers As the deposition layer increases, the accumulated heat capacity increases, the thermal conductivity of the substrate changes, and the width of the heat-affected zone changes compared to the first layer. For the second layer... Outer ring diameter setting value of the layer Corrected according to the following relationship: in: Interlayer thermal accumulation compensation coefficient (dimensionless), determined by the material's thermal conductivity and single-layer thickness, is provided by a database, with a typical value range of 0.02 to 0.08; The logarithmic function reflects the physical law that the heat accumulation effect gradually saturates with the increase of the number of layers—the heat accumulation effect changes significantly when the number of lower layers increases, and the change tends to saturate when the number of upper layers increases; : No. Real-time humidity readings inside the enclosure before the layer repair process begins, via The current state of the gas phase region is incorporated into the calculation of the ring diameter of the layer, so that the interlayer compensation not only considers the heat accumulation effect, but also responds synchronously to the humidity changes of the gas phase region during the repair process.

[0022] Each floor In The full-layer budget for the item (heat accumulation compensation part) is completed before the repair begins, forming a sequence ring diameter budget table; The humidity correction section updates the current humidity reading in real time before each layer is started. The two parts are then combined to drive the conical lens group to adjust to the corresponding ring diameter. Only after the adjustment is completed will the repair of that layer be started. This hybrid strategy of budget plus real-time updates balances computational efficiency and environmental adaptability.

[0023] S5, multi-layer, multi-channel repair execution, officially initiating the repair process. The inner and outer light spots work synchronously, according to the budget of S4. The sequence automatically adjusts the outer ring diameter to the corresponding budgeted value before each layer of repair begins, and switches the corresponding feedforward ring diameter value according to the velocity segment during path execution. The first-stage feedforward constitutes the ring diameter control framework for the entire repair process, covering the ring diameter changes caused by repair velocity variations and interlayer heat accumulation effects. Its magnitude of change is the largest (typical range: adjustments due to velocity variations can reach ±1.5 mm, and interlayer compensation accumulation can reach over +2 mm). During repair execution, the humidity in the gas phase region... The PI control system from step one maintains the humidity level continuously, outputting its real-time value at a frequency of 10Hz to the outer ring diameter adjustment module. When the humidity reading changes more than a set threshold relative to the previous frame... (Typical value: 3%RH) When, according to The function performs real-time correction on the current outer ring diameter, and the correction amount is superimposed on the current first-level feedforward value: in The current real-time humidity. The initial humidity at the start of this layer. The second-level regulation responds to the dynamic fluctuations in the gas phase region during the repair process, compensating for the lag in the feedforward calculation for humidity changes, with a moderate magnitude of change (typical range: ±0.5~±1.0mm).

[0024] The visual sensor continuously acquires images of the cleaning effect in the outer ring of the light spot at a frame rate of 60Hz, and the oxide scale removal rate in the outer ring irradiated area is calculated in real time using image processing algorithms. It is defined as the percentage of the area within the outer ring's effective width where the reflectivity reaches the clean metal reference value.

[0025] The adjustment logic is as follows: when (Set value: 85%), at the current Increase the outer ring diameter by one step based on the existing structure. (Step size setting: 0.5mm), while proportionally reducing the outer ring laser power density to maintain constant energy input per unit area; when Furthermore, if the cleaning width allowance exceeds the reasonable range (more than 10% of the theoretical width), reduce the outer ring diameter by one step. Increase the power density of the outer ring proportionally; when exist to When the setting is between 95%, the current outer ring diameter remains unchanged.

[0026] This adjustment level has the smallest magnitude of change (typical range: within ±0.5mm) and is only used to compensate for the residual errors of the first two levels.

[0027] In addition, this step also includes cross-system exception response: If the outer ring diameter has been adjusted to the first and second levels, and the third-level fine-tuning step size has reached the set upper limit (more than 4 consecutive adjustments), then... ),and Still below for multiple consecutive frames (more than 5 consecutive frames) The system determines this situation as a signal of actual deterioration in the gas phase zone (rather than simply insufficient cleaning range), and automatically triggers the gas phase zone control system to enter enhanced mode, executing the following steps in sequence: Immediately increase the protective gas flow rate to 200% of the normal flow rate and perform high-flow purging; Pause repair (stop wire feeding, turn off inner laser, maintain low power for outer laser to maintain temperature), and keep the outer laser spot working in the current position; Waiting for humidity Falling back to The following will occur, and after the duration exceeds 30 seconds, normal repair will resume; If the humidity fails to return to the permissible threshold within 5 minutes, a critical alarm will be triggered, prompting a check of the sealing status to prevent repairs from being carried out while the gas phase is still in a state of continuous failure, which could lead to the scrapping of the entire layer.

[0028] In this step, after each repair layer is completed, a 3D structured light profilometer performs a rapid scan of the current layer surface (the scan time is usually within 30 seconds) to obtain the actual layer height. and with theoretical height The deviation is compared and fed back to the wire feeding speed controller to adjust the wire feeding amount for the next layer; at the same time, the measured width of the heat-affected zone is compared with... If the measured values ​​deviate from the budgeted values ​​by more than a threshold (±0.3mm) for two consecutive layers, the subsequent layers will be affected. The coefficients are corrected online to continuously improve the accuracy of interlayer compensation.

[0029] S6. Post-repair in-situ quality assessment and repair judgment: After all repair layers are completed, maintain the flow of protective gas (to prevent secondary oxidation in the high-temperature repair area). Once the repair area has cooled to below 100℃, perform a full-area geometric scan using a 3D structured light profiler, outputting a geometric compliance report including indicators such as geometric conformity, layer height uniformity, and surface roughness. If there are geometric deviations (deviations exceeding design tolerances) in local areas, the system automatically identifies the outline of the deviation area, plans a local repair path, and repeats steps one to five to locally repair the deviation area until the overall geometric conformity meets the acceptance criteria.

[0030] In summary, there are three levels of synergistic relationship between the gas phase region closed-loop control subsystem and the outer ring diameter dynamic adjustment subsystem of this invention: First, there is the positive driving relationship; the real-time humidity value in the gas phase region is obtained through... The function directly participates in the feedforward calculation and real-time correction of the outer ring diameter, while the humidity output of the gas phase control system serves as the continuous dynamic input to the outer ring diameter adjustment system. The data transmission path between the two forms a positive control chain from environmental perception to process response.

[0031] Secondly, there is a reverse linkage. The cleaning effect signal from the visual sensor drives the fine adjustment of the outer ring diameter while indirectly observing the actual state of the gas phase zone. When the cleaning effect remains abnormal, it triggers the enhanced control mode of the gas phase zone. The abnormal state of the outer ring diameter adjustment system becomes the trigger signal for the gas phase zone control system, forming a reverse linkage chain from process results to environmental control.

[0032] Finally, the joint criterion relationship is established, in which the two subsystems jointly constitute the joint criterion for repair permission during the repair initiation phase. Repair is not allowed to start if either subsystem has not completed initialization, thus ensuring the coordination and consistency of the two throughout the repair process at the system level.

[0033] The synergistic relationship among the three levels mentioned above enables the two subsystems to form an organic whole. The gas phase zone control system compensates for the blind spot of the outer ring diameter regulation system in terms of sensing changes in environmental humidity, while the outer ring diameter regulation system compensates for the lack of direct sensing of local cleanliness status by the gas phase zone control system. The two complement each other and work together to achieve comprehensive coverage and coordinated response to environmental disturbances during underwater remediation.

[0034] Compared with the prior art, the present invention has the following beneficial effects: 1. The implicit impact of humidity fluctuations in the gas phase zone on the quality of restoration is explicitly incorporated into the control. The outer cleaning range is automatically adjusted with changes in humidity, eliminating the systemic blind spot of silent degradation of restoration quality when the stability of the gas phase zone decreases in existing methods. 2. The three-level dynamic adjustment of the outer ring diameter covers three main sources of disturbance: changes in repair speed, interlayer heat accumulation effect, and humidity fluctuations in the gas phase region, which greatly improves the robustness of the process; 3. The cross-system abnormal linkage mechanism enables visual feedback of abnormal cleaning effect to trigger the gas phase zone enhancement response in a timely manner, preventing the overall quality of the layer from being scrapped due to continuous repair in the gas phase zone failure state. 4. The no-run calibration mechanism reduces the dependence on the accuracy of database parameters and reduces the impact of feedforward calculation model errors on repair quality; 5. All of the above methods are implemented on the basis of existing devices through sensor integration and control software, without the need for major modifications to the main structure of the device, resulting in low engineering implementation costs and easy promotion and application.

[0035] On the other hand, the present invention also provides an underwater laser coaxial fuse repair device that uses gas phase region state sensing to drive dynamic adjustment of the outer ring diameter.

[0036] The device has a coaxial cylindrical structure and is installed on the flange at the end of the underwater robotic arm. With the laser emission axis as the reference axis, the functional components are arranged radially from the inside to the outside in layers, forming a three-layer nested coaxial structure of laser beam path, gas phase zone and drainage sealing outer layer.

[0037] Since this invention is an improvement on existing underwater repair technology for dotted ring spots, the following will only focus on the improved part, namely the optical system for forming an adjustable outer ring diameter dotted ring spot.

[0038] This section performs two functions: first, it shapes a single laser beam into a composite shape of an inner high-energy spot and an outer low-energy ring spot; second, it dynamically adjusts the diameter of the outer ring spot in real time during the repair process. The laser beam is transmitted to the input end of the device via an external optical fiber, and after being collimated by a collimation module (collimation focal length selectable from 50 to 80 mm), it outputs a parallel beam and enters the spot-ring shaping optical path. The shaping optical path consists of the following optical elements arranged sequentially along the optical axis: a beam splitter (ring mirror), an inner spot focusing module, an outer ring diameter dynamic adjustment module, an outer focusing module, and a beam combining outlet. The core design principle of the above optical path is that the inner and outer ring optical paths propagate independently after beam splitting, and each completes focusing and shaping to form a composite spot on the workpiece surface. An adjustable module is inserted in the outer ring optical path to achieve independent control of the ring diameter. The focusing planes of both are located on the workpiece repair surface.

[0039] The ring diameter dynamic adjustment module is an improved part, while the rest are standard technologies, which are present in existing devices that use dotted ring spots for underwater laser filament repair, and therefore will not be described in detail. The ring diameter dynamic adjustment module consists of the following components: An outer collimating lens re-collimates the deflected divergent beam into a parallel annular beam, providing uniform illumination for subsequent cone lens shaping. This is typically a curved lens.

[0040] b. An adjustable conical lens group consists of two axial conical mirrors with the same apex angle arranged coaxially along the optical axis. The first axial conical mirror is fixed, while the second axial conical mirror is mounted on a precision axial displacement platform and can move back and forth along the optical axis. The axial distance between the two axial conical mirrors is... It is an adjustable quantity.

[0041] The working principle of an axial-cone pair is as follows: a parallel annular beam of light is refracted by the first axial-cone to form a conical beam; the second axial-cone then readjusts the light into a parallel annular beam, ultimately outputting still parallel annular light, but the diameter of the ring has changed, and the radius of the parallel annular beam has increased. The axial distance between the two axial conical mirrors The determination is that increasing the spacing increases the ring radius, and decreasing the spacing decreases the ring radius. This quantitative relationship is written into the control lookup table after optical calibration.

[0042] The axial spacing between the two axial cone mirrors is designed to be adjustable from 0 to 25 mm, corresponding to an adjustment range of approximately [missing information - likely related to outer ring spot diameter]. This covers the entire ring diameter adjustment range required by the method of the present invention.

[0043] The c-axis displacement actuator uses a piezoelectric ceramic linear actuator (PZT) to drive the displacement platform of the second axial cone mirror. The actuator has a stroke of 25 mm, a displacement resolution of 0.5 μm, and a closed-loop position feedback system with a grating encoder and a response time of less than 50 ms. The piezoelectric actuator is an underwater-sealed type, and a flexible hinge connects the actuator to the displacement platform to eliminate the influence of the driving torque on the optical elements. The actuator receives digital commands from the co-controller, specifically the target ring diameter value mentioned in the method section, which is converted into the corresponding target displacement value via a lookup table before execution.

[0044] The outer focusing lens group focuses the parallel annular beam output from the adjustable conical lens group onto the workpiece surface, forming an annular linear light spot. Its focal length matches that of the inner focusing module, ensuring confocal focusing of the inner and outer light spots. The focusing lens group is also fixedly installed.

[0045] The water shield serves as the physical carrier for establishing the gas phase zone. It has an overall cup-shaped structure with a downward opening, coaxially fixed to the laser emitter head and moves with the entire device. The water shield consists of a double-layered coaxial structure formed by an outer drainage chamber and an inner exhaust chamber. An annular gap is formed between the outer wall of the water shield and the workpiece surface. After the protective gas enters from the air inlet at the top of the device, it preferentially fills the outer drainage chamber, forming an air curtain that pushes external water outwards, establishing the first drainage barrier at the workpiece contact surface. The bottom opening edge of the outer drainage chamber has a flexible sealing lip, forming a flexible contact seal with the workpiece surface to reduce water leakage through the sealing gap. An inner exhaust chamber is located inside the outer drainage chamber, coaxial with the laser emission axis, and with a diameter slightly larger than the laser emission port. After being pressurized by the outer drainage chamber, the protective gas enters the inner exhaust chamber through the airflow distribution hole between the inner and outer chambers, forming a downward-flowing laminar protective atmosphere, establishing a clean gas phase protection zone above the laser-affected area on the workpiece surface. In addition, this part is equipped with corresponding sensors and vision sensors to acquire the data required by the aforementioned method. Attached Figure Description

[0046] Figure 1 A flowchart of an underwater laser coaxial fuse repair method with adjustable outer ring diameter provided by the present invention; Figure 2 This is a side cross-sectional schematic diagram of an underwater laser coaxial fuse repair device provided by the present invention; Figure 3 This is a schematic diagram illustrating the use of a set of axial conical lenses to adjust the aperture size in this invention.

[0047] Figure Labels 100. Workpiece to be repaired; 1. Drainage cover; 2. Wire feeding mechanism; 201. Fuse material; 3. Laser head; 4. Ring diameter dynamic adjustment module; 401. Fixed lens; 402. Moving lens; 403. Piezoelectric ceramic linear actuator; 5. Humidity sensor; 6. Image sensor; 7. Pressure sensor. Detailed Implementation

[0048] To enable those skilled in the art to better understand the present application, the technical solutions in specific embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by those skilled in the art.

[0049] The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects.

[0050] Example 1 The workpiece to be repaired is a titanium alloy (TC4, Ti-6Al-4V) conduit component of a marine platform, located at an underwater depth of approximately 12 meters (hydrostatic pressure approximately 0.12 MPa). The workpiece surface has an erosion groove defect approximately 80 mm long, with a maximum depth of approximately 4 mm and a width of approximately 10 mm. Repair objectives: To fill the defective area to be flush with the original surface, with a geometric deviation better than ±0.3 mm, ensuring good adhesion between the repair layer and the substrate, and free from defects such as porosity and cracks.

[0051] TC4 material parameters: thermal diffusivity mm 2 / s; Material oxidation sensitivity correction coefficient This data indicates that titanium alloys are extremely sensitive to oxygen; humidity sensitivity coefficient. This data was determined from TC4 oxidation kinetics data; interlayer heat accumulation compensation coefficient. .

[0052] S1: After the device is positioned, argon gas is introduced into the water shield, with an initial flow rate of 8 L / min. The dew point sensor (range 0–100%RH, accuracy ±1.5%RH) and the pressure sensor (range 0–0.5MPa, accuracy ±0.5kPa) begin to collect data in real time.

[0053] Pressure setpoint MPa, slightly higher than ambient water pressure to maintain positive pressure sealing, allowable deviation Approximately 40 seconds after establishing the gas phase region, the pressure stabilized. The seal integrity criterion was met at kPa. After continuing ventilation for approximately 90 seconds, the humidity dropped to 13.6% RH, which is below [the threshold]. The RH (respiratory phase) cleanliness criterion is met.

[0054] The PI controller takes over flow control, locking the target humidity at 8%RH (dead zone: ±2.5%RH) and adjusting the stable flow rate to approximately 5.5L / min. Real-time humidity values ​​are output at a frequency of 10Hz: current stable value. RH is used as the humidity input for subsequent steps. The gas phase region is now established; proceed to S2 to wait for the outer annular diameter to be initialized.

[0055] S2: Repair parameters: Inner circle spot diameter mm, lead distance mm, planned repair line speed mm / s (straight section), decelerate at path corners. mm / s (treatment of damaged ends).

[0056] Calculate the reference ring diameter of the straight segment: Calculate the reference ring diameter of the end corner segment ( mm / s): Forming the loop feedforward sequence: straight line segment mm, end corner section mm, written to the path execution controller. The cone lens group is axially adjusted to the corresponding position, a ready signal is output, all joint criteria are met, and entry into S3 is allowed.

[0057] S3: by The machine performs a no-load run at mm / s, with only the outer ring light spot (60W power) activated, and the visual sensor sampling frequency is 30Hz.

[0058] Statistics after the empty walk: sampling points on the straight line segment The average value is 7.76 mm. mm, mm (cleaning width is too narrow, systematic deviation is negative).

[0059] All 12 consecutive sampling points showed the same direction of deviation (all negative deviations), and the average absolute value was 0.32mm > 0.3mm, triggering calibration correction. The corrected annular feedforward sequence has been updated. The time from the end of the idle run to the start of the formal repair was 82 seconds, which is within the 120-second limit, so no secondary pre-cleaning is required.

[0060] S4: The defect depth is 4mm, and the thickness of a single layer is approximately 0.8mm. A 5-layer repair plan (including redundancy) is proposed. Each layer... The budget is as follows (humidity correction will be entered in real time before each floor starts):

[0061] Before each layer is activated, the current time is entered. Value Calculation Then, multiply by the corresponding value in the table above to get the final result. .

[0062] S5: First layer of repair (n=1): Humidity before startup RH, , mm. After the feedforward settings are complete, start the first layer of repair.

[0063] Humidity remained stable during the repair process. Between RH, the second-level humidity correction is triggered 3 times (humidity change exceeds). (RH), each correction is approximately ±0.15 mm, with a stable response within the second-level range. The visual sensor provides feedback on the oxide scale removal rate. Stable at Between these, the third-level fine-tuning triggers two small adjustments (each +0.5mm before resuming), and the repair process proceeds smoothly.

[0064] A gas phase disturbance event occurred during the third layer repair (n=3) process: At the 28-second mark of the repair process, the robotic arm adjusted its posture, causing a slight tilting of the enclosure, briefly worsening the seal and causing the humidity to drop from [previous value]. RH rose rapidly to [a certain level] in approximately 8 seconds. RH (exceeding) ).

[0065] The second-level humidity correction responds immediately, increasing the outer ring diameter from the current value of 8.69 mm, but since the humidity has already exceeded [a certain threshold], [further adjustments are needed]. , Exceeding design limits, visual feedback The humidity dropped to 79% (below 4 seconds after it rose) The third-level fine adjustment increases the outer ring diameter by 2 steps (+1.0mm).

[0066] After 6 consecutive frames Furthermore, the fine-tuning had reached its limit, triggering a cross-system abnormal linkage: the gas flow rate increased to 11 L / min (normal flow rate 200%), and repair was paused. The humidity returned to normal after 39 seconds. If the RH remains below the threshold for 30 seconds, the system will resume repair. The repair position remains unchanged during the pause; upon resumption, the arc will be restarted with a 10mm overlap to ensure bonding quality at the break point.

[0067] After the third layer of repair was completed, structured light scanning showed the actual layer height. mm, with target The deviation is only +0.03mm, which is within the error range, so the wire feed amount does not need to be adjusted.

[0068] Fifth layer of repair (n=5): The repair process is smooth. Maintained throughout All three levels of regulation operated within the normal range. Repair complete.

[0069] S6: After cooling to 96℃, a full-area geometric scan was performed. The report shows that the average remaining height of the repaired area is +0.12mm (within the subsequent machining allowance), and the geometric deviation is better than ±0.25mm, meeting the ±0.3mm acceptance standard. The surface quality is good, with no visible cracks or large pores. No local repairs are needed; the repair is complete.

[0070] Example 2 The object to be repaired is a group of corrosion pits in the weld area of ​​a low-carbon steel (Q345B) pipe (outer diameter 219mm, wall thickness 8mm) on an offshore platform. The water depth is approximately 8 meters, the maximum depth of the corrosion pits is 2.5mm, and the distribution area is approximately 30mm × 40mm. The repair wire is ER70S-6 low-carbon steel copper-plated welding wire with a diameter of 0.8mm.

[0071] Q345 material parameters: thermal diffusivity mm 2 / s; Material oxidation sensitivity correction coefficient (Low carbon steel has low oxidation sensitivity); humidity sensitivity coefficient Interlayer heat accumulation compensation coefficient The radius of curvature of the pipe surface is approximately 109.5 mm. The repair path is a short arc segment along the pipe axis, with changes in curvature direction at both ends of the path's centerline.

[0072] S1: The vapor phase region was established successfully, and the humidity decreased in approximately 55 seconds. RH, stable sealing pressure, and the combined criteria are met. The steel has low oxidation sensitivity, and the target humidity value is set at [value missing]. RH, Dead Zone ± RH.

[0073] S2: Planned repair line speed mm / s, mm, current RH.

[0074] Note Q345 Smaller (0.85) and The value is relatively small (0.18), indicating a low feedforward calculation result. mm is significantly smaller than the value corresponding to TC4 in Example 1, which reflects the adjustment effect of the material oxidation sensitivity correction coefficient among different materials, that is, low carbon steel requires a smaller cleaning range under the same humidity conditions.

[0075] S3: Visual sensor statistics after empty walk For mm, if the absolute value is less than 0.3 mm, the trigger threshold will not trigger systematic calibration; it will proceed directly as... mm is used as the first layer of repair baseline. The interval between idle run and repair start is 67 seconds, which meets the 120-second requirement.

[0076] S4: The defect depth is 2.5mm. A 3-layer repair plan is proposed, with budgets for each layer. (Before humidity correction) are as follows: mm, mm, mm.

[0077] S5: Three-layer restoration process Stable at Between, the range of humidity fluctuations in the gas phase region RH, Level 2 humidity correction triggered 5 times (total adjustment not exceeding ±0.2mm), Level 3 visual fine-tuning triggered 4 times (total adjustment step not exceeding 1 step). No abnormal linkage triggers occurred throughout the process. The total repair time for the three layers was approximately 18 minutes, and the repaired area was completely filled.

[0078] S6: After cooling, the geometric scan showed a global geometric deviation of ±0.18mm, which is better than the acceptance standard of ±0.3mm, and no repair is required.

[0079] This embodiment demonstrates that for low-carbon steel materials with low oxidation sensitivity, the method of the present invention can achieve excellent repair quality with a small outer ring diameter reference, with fewer trigger times for the three-level adjustment and a more stable repair process, proving that the control logic of the method has good material universality.

[0080] Example 3 The object to be repaired is an underwater equipment support component for a nuclear power plant. The material is Inconel 625 nickel-based superalloy. The workpiece has an arc-shaped surface with a radius of curvature of approximately 80 mm, and surface corrosion pits with a depth of approximately 3 mm, distributed over an area of ​​approximately 25 mm × 35 mm. It is located at an underwater depth of approximately 5 meters. The repair wire is ERNiCrMo-3 welding wire (approximately the composition of Inconel 625), with a diameter of 0.8 mm.

[0081] Inconel 625 material parameters: thermal diffusivity mm 2 / s; Material oxidation sensitivity correction coefficient (Nickel-based alloys have high oxidation sensitivity); humidity sensitivity coefficient Interlayer heat accumulation compensation coefficient .

[0082] Because the workpiece is a curved surface, the repair path exhibits continuous speed changes at the transition points of the curved surface. Therefore, the repair path is divided into 7 speed zones during the path planning stage. (Graded changes from 4.5 mm / s to 7.5 mm / s), calculate the values ​​for each segment. The value forms a 7-segment feedforward loop sequence. The same current humidity is substituted into the calculation of each segment. RH (reading after stabilization in step one): by The calculation is based on mm / s (the main straight segment). In 7-segment feedforward sequence The range is from 7.81mm ( The fastest speed range is 10.27 mm / s (the highest speed range). (Slowest segment: mm / s) The feedforward sequence automatically switches according to the path position to ensure that the cleaning range at different curvatures always matches the actual needs.

[0083] This restoration involved four layers, with new materials being installed between the second, third, and fourth layers. Value recalculated And update each section Because the overall humidity remains at Between RH, The correction amount fluctuated slightly between approximately 1.24 and 1.31, with stable interlayer adjustment.

[0084] In the second layer of repair, the outer ring diameter underwent a third-level visual fine-tuning process, triggering three consecutive steps plus 1.5mm, but afterwards... The percentage rose to 86% (exceeding 85%), but did not trigger any cross-system abnormal linkage. Subsequent analysis concluded that this adjustment was a normal response to a slight decrease in the quality of the local sealing contact on the curved surface, and did not constitute a gas phase failure event.

[0085] The final full-area geometric scan showed a deviation of ±0.21mm, which meets the ±0.25mm requirement of the nuclear power plant equipment repair standard, and the repair is qualified.

[0086] The three embodiments above cover materials with different oxidation susceptibility (TC4, Q345, Inconel 625), different repair depths (2.5~4mm), different workpiece geometries (planar, curved, pipe arc), and different water depth conditions, verifying the applicability and effectiveness of the method of the present invention in various typical application scenarios. The handling process of gas phase disturbance events in Embodiment 1 fully demonstrates the actual operation of the cross-system abnormal linkage mechanism, which is the most direct embodiment of the core innovative value of the present invention.

[0087] Example 4 This embodiment introduces the underwater laser coaxial fuse repair device provided by the present invention. This device can be directly improved based on existing underwater laser coaxial fuse repair devices of the same type, such as... Figure 2 As shown, the system includes a drainage cover 1, a wire feeding mechanism 2, and a laser head 3 (including a laser emitter and a beam splitting structure modulated into a dotted ring spot, all of which are existing technologies). The drainage cover 1 forms a vapor phase region on the surface of the workpiece 100 to be repaired, facilitating laser repair. The wire feeding mechanism is responsible for delivering the molten wire material 201 to the point to be repaired, working in conjunction with the laser head to complete the repair. The improvement lies in the inclusion of a ring diameter dynamic adjustment module 4, whose main structure consists of two axial conical lenses with the same apex angle, such as... Figure 3As shown, the first axial conical lens closest to the incident annular beam is a fixed lens 401, and the second axial conical lens, mounted on a piezoelectric ceramic linear actuator, is a movable lens 402. The piezoelectric ceramic linear actuator 403 drives the movable lens 402 to move linearly relative to the fixed lens 401, changing the distance between them. After refraction by the fixed lens 401, the parallel annular beam forms a conical beam; the movable lens 402 readjusts the light into a parallel annular beam. The final output is still an annular parallel beam, but the diameter of the ring has changed. The radius of the parallel annular beam is determined by the axial distance between the two axial conical lenses; increasing the distance increases the radius, and decreasing the distance decreases the radius. This quantitative relationship is written into a control lookup table after optical calibration. The piezoelectric ceramic linear actuator 403 is controlled by an industrial control system. According to the aforementioned method, the industrial control system receives parameters from various sensors, including a humidity sensor 5, an image sensor 6, and a pressure sensor 7. After calculation, it issues adjustment commands to control the piezoelectric ceramic linear actuator 403 to adjust the distance between the movable lens 402 and the fixed lens 401, thereby adjusting the size of the annular beam.

[0088] Finally, it should be noted that the described embodiments are merely some, not all, of the embodiments of the present invention. Those skilled in the art will understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the claims and their equivalents; that is, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A method for repairing underwater laser coaxial fuses with adjustable outer ring diameter, characterized in that, Includes the following steps: S1. Joint Criteria Confirmation for the Establishment and Repair of the Gas Phase Zone: Establish an initial gas phase protection zone, collect relative humidity and air pressure inside the enclosure in real time, and allow the subsequent steps only when the seal integrity criterion and the gas phase zone cleanliness criterion are met simultaneously. S2. Initial setting of outer ring diameter: Calculate the reference value of outer ring diameter based on parameters such as the current humidity value in the gas phase region; S3, No-load path verification, substrate pre-cleaning and feedforward ring diameter value physical calibration: Perform no-load path verification and perform physical calibration on the ring diameter value obtained from the feedforward calculation; S4. Budgeting and initialization of interlayer outer ring diameter compensation and repair parameters: Budgeting the interlayer compensation value of the outer ring diameter of each repair layer; S5. Multi-layer and multi-channel repair execution: The inner and outer ring light spots work synchronously, and the outer ring diameter is dynamically adjusted during the execution process; S6. Post-repair in-situ quality assessment and repair judgment: Perform a full-area geometric scan. If out-of-tolerance conditions are found, perform local repair.

2. The method according to claim 1, characterized in that, In S1, the joint criteria include: the seal integrity criterion is that the absolute pressure difference is not greater than the allowable pressure deviation threshold; the gas phase cleanliness criterion is that the relative humidity is not greater than the set threshold.

3. The method according to claim 1, characterized in that, In step S2, a dynamic humidity correction function for the gas phase region is introduced to calculate the baseline value of the outer ring diameter. The function is defined as follows: ,in Humidity sensitivity coefficient This is the real-time humidity of the current gas phase region. Set a threshold for relative humidity.

4. The method according to claim 1, characterized in that, In S3, if there is a systematic deviation between the measured effective cleaning width and the theoretical cleaning width, the outer ring diameter reference value is corrected as a whole. The criteria for judging the systematic deviation are that more than 5 consecutive sampling points on the path all deviate in the same direction, and the absolute value of the average deviation exceeds 0.3mm.

5. The method according to claim 1, characterized in that, In step S4, as the number of repair layers increases, the outer ring diameter setting value of each layer is corrected. The correction relationship includes an interlayer heat accumulation compensation term and a correction term based on real-time humidity. The interlayer heat accumulation compensation uses a logarithmic function to reflect the physical law that the heat accumulation effect gradually tends to saturate as the number of layers increases.

6. The method according to claim 1, characterized in that, In S5, the outer ring diameter is adjusted according to the changes in ring diameter caused by the changes in repair speed and the interlayer heat accumulation effect, or it is adjusted in real time according to the dynamic fluctuations of the gas phase zone during the repair process, based on the humidity dynamic correction function.

7. An underwater laser coaxial fuse repair device for implementing the method of any one of claims 1 to 6, comprising a device body with a coaxial cylindrical structure, wherein, radially from the inside out, there are a dotted ring laser spot system, a gas phase region, and a drainage sealing outer layer, characterized in that, The dot ring spot system is equipped with a ring diameter dynamic adjustment module that can adjust the radial size of the outer ring spot.

8. The apparatus according to claim 7, characterized in that, The ring diameter dynamic adjustment module includes an adjustable conical lens group, which consists of two axial conical lenses with the same apex angle arranged coaxially along the optical axis; wherein the second axial conical lens is mounted on a precision axial displacement platform and can move back and forth along the optical axis to change the axial distance between the two axial conical lenses, thereby changing the ring radius of the outer parallel ring beam.

9. The apparatus according to claim 8, characterized in that, The displacement platform of the second axial cone mirror is driven by a piezoelectric ceramic linear actuator.

10. The apparatus according to any one of claims 7-9, characterized in that, The device is installed on the end flange of the underwater robotic arm.

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