Stable supporting structure system and method suitable for offshore additive manufacturing

Abstract

The invention belongs to the technical field of additive manufacturing, and particularly discloses a stable supporting structure system and method suitable for offshore additive manufacturing. Comprising a data acquisition system, a dynamic stable platform, an additive manufacturing unit and a real-time control module, and an inertial measurement sensor of the data acquisition system monitors the attitude of a damping cabin and transmits data; the dynamic stable platform counteracts vibration displacement according to an instruction of the real-time control module and provides a stable basis for a printing system; the additive manufacturing unit is fixed through a top cantilever structure, so that maintenance and accurate control are facilitated; and the real-time control module is combined with a multi-source information real-time regulation and control The stability of the offshore additive manufacturing equipment is remarkably improved, the environmental adaptability is enhanced, the maintenance convenience is improved, reliable operation of the equipment is guaranteed, and the offshore additive manufacturing problem is effectively solved.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology, and more specifically, relates to a stable support structure system and method suitable for marine additive manufacturing. Background Technology

[0002] As a critical system in the shipbuilding industry, marine equipment must meet stringent requirements for high reliability, long service life, and handling complex sea conditions. This poses significant challenges to material performance, manufacturing precision, and maintenance efficiency. Additive manufacturing technology, with its advantages of high-precision forming, high performance, high material utilization, and integrated manufacturing of complex structures, has become a key support for the rapid manufacturing and emergency maintenance of marine equipment. Among them, laser metal additive manufacturing technology achieves the direct forming of complex metal components by precisely controlling the melting process of metal powder or wire with a laser beam, significantly improving manufacturing efficiency and quality. However, the extreme conditions unique to the marine environment, such as continuous shaking, vibration, and high humidity salt spray, cause traditional additive manufacturing equipment to face significant stability problems when operating at sea: the six-degree-of-freedom motion of the ship causes the relative position of the laser and material to shift, resulting in turbulent temperature / flow fields in the molten pool, leading to poor forming, porosity in the cladding layer, cracks, and even printing failure. Existing land-based additive manufacturing equipment lacks a dedicated stable structure for marine conditions, making it difficult to adapt to the complex marine environment and severely restricting the application and expansion of this technology in the field of marine engineering. Therefore, developing new support structures that are resistant to disturbances, highly adaptable to the environment, and can ensure the stable operation of additive manufacturing equipment has become an urgent need to promote the development of high-performance marine manufacturing technology. Summary of the Invention

[0003] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a stable support structure system and method suitable for offshore additive manufacturing. It integrates data acquisition, dynamic stabilization, additive manufacturing, real-time control, and environmental adaptation modules into a closed vibration-damping chamber. The data acquisition system monitors the chamber's attitude and transmits data via inertial measurement sensors; the dynamic stabilization platform counteracts vibrations according to commands from the real-time control module, providing a stable foundation for printing; the additive manufacturing unit is fixed with a top cantilever, facilitating maintenance and precise control; the real-time control module integrates a multi-source information control system, significantly improving the stability of offshore additive manufacturing equipment, enhancing environmental adaptability, improving maintenance convenience, ensuring reliable equipment operation, and effectively solving the challenges of offshore additive manufacturing.

[0004] To achieve the above objectives, according to one aspect of the present invention, a stable support structure system suitable for marine additive manufacturing is proposed, comprising a closed vibration damping chamber and a dynamic stabilization platform, a data acquisition system, an additive manufacturing unit, and a real-time control module disposed within the closed vibration damping chamber, wherein...

[0005] The dynamic stabilization platform includes a six-degree-of-freedom Stewart structure for keeping the workpiece to be printed horizontal.

[0006] The additive manufacturing unit includes a laser printhead and a three-axis motion module for driving the movement of the laser printhead;

[0007] The data acquisition system is used to acquire in real time the motion and attitude data of the enclosed shock-absorbing chamber, the wave motion trend data, and the printhead position data of the additive manufacturing module;

[0008] The real-time control module uses the wave motion trend data and a feedforward compensation module to generate a pre-correction amount for the printhead trajectory to correct the high-frequency micro-vibrations of the additive manufacturing module. At the same time, based on the real-time motion and attitude data of the shock-absorbing chamber and the printhead position data, the feedback compensation module corrects the posture error of the dynamic stabilization platform to compensate for the low-frequency large displacement motion of the dynamic stabilization platform. The module also adjusts the material extrusion rate of the printhead synchronously according to the motion state of the dynamic stabilization platform to keep the printed layer thickness consistent.

[0009] As a further preferred embodiment, the data acquisition system includes an inertial measurement unit, a wave radar, and a laser tracker. The inertial measurement unit, wave radar, and laser tracker transmit the motion and attitude data of the enclosed shock-absorbing chamber, the wave motion trend data, and the printhead position data to the real-time control module via an EtherCAT bus, and communicate using SPI or CAN bus protocols.

[0010] As a further preferred embodiment, the inertial measurement unit integrates a triaxial accelerometer, a gyroscope, and a magnetometer.

[0011] As a further preferred embodiment, the dynamic stabilization platform includes a six-DOF Stewart structure, which comprises an upper platform, a lower platform, and six sets of electric servo drive cylinders. The upper platform is connected to the upper ends of the six sets of electric servo drive cylinders via ball joints or Hooke joints. The lower platform serves as a fixed base and is fixed to the load-bearing frame at the bottom of the enclosed shock-absorbing chamber by a set of high-strength bolts. The lower platform is connected to the lower ends of the six sets of electric servo drive cylinders, which are symmetrically distributed between the upper and lower platforms.

[0012] As a further preferred embodiment, the feedforward compensation module includes an optimization calculation unit based on constraint model predictive control, used to generate a smooth and unsaturated printhead advance correction trajectory while meeting the safety limits of the stroke, speed, and attitude of the electric servo drive cylinder executing the six-degree-of-freedom Stewart structure.

[0013] As a further preferred embodiment, the additive manufacturing unit synchronously adjusts the material extrusion flow rate through the following relationship:

[0014]

[0015] Where h(t) is the printing layer thickness, w(t) is the track width corrected in real time according to the tilt angle of the dynamic stabilization platform, and v path (t) represents the instantaneous relative velocity between the printhead and the dynamically stabilized platform.

[0016] According to another aspect of the present invention, an additive manufacturing method suitable for marine shipboard equipment is also provided, comprising the following steps:

[0017] Step 1: Obtain real-time motion and attitude data of the shock absorber, wave motion trend data, and printhead position data of the additive manufacturing module at the current moment;

[0018] Step 2: Based on the wave motion trend data, a feedforward compensation algorithm is used to generate a pre-correction amount for the printhead trajectory to correct the high-frequency micro-vibrations of the additive manufacturing module. At the same time, based on the real-time motion and attitude data of the shock absorption chamber and the printhead position data, a feedback compensation algorithm is used to correct the pose error of the dynamic stabilization platform to compensate for the low-frequency large displacement motion of the dynamic stabilization platform.

[0019] Step 3: Adjust the material extrusion rate of the print head synchronously according to the motion state of the dynamic stabilization platform to ensure that the thickness of the printed layer remains consistent.

[0020] As a further preferred embodiment, step two, which involves generating a pre-correction amount for the printhead trajectory using a feedforward compensation algorithm based on the wave motion trend data, includes the following steps:

[0021] (21) Based on the wave motion trend data, the dominant frequency family and amplitude of the platform disturbance are obtained, the hull disturbance prior is constructed, and the future [t] is generated based on the hull disturbance prior. k , t k Prior trajectory of printhead pose within the time interval +Δt]

[0022] (22) Based on the expected trajectory of the print head and the prior pose trajectory The difference is used to generate a pre-correction amount for the printhead trajectory to correct for the high-frequency micro-vibrations of the additive manufacturing module;

[0023] (23) The pre-correction trajectory of the printhead is optimized by using a constraint model predictive control to ensure that the compensation amount is smooth and does not exceed the speed and travel range of the dynamic stability platform.

[0024] As a further preferred embodiment, in step three, the motion state of the dynamic stabilization platform and the relative speed v of the printhead are considered. path (t), real-time adjustment of material volumetric flow rate Make the printed layer thickness h(t) satisfy:

[0025]

[0026] Where w(t) is the nozzle width that is corrected in real time based on the platform tilt angle.

[0027] As a further preferred embodiment, the correction formula for the nozzle width w(t) is:

[0028] w(t)=w0(1+k α sinα(t)),

[0029] w0 is the nominal track width under horizontal attitude, α(t) is the real-time tilt angle, and k α These are empirical calibration coefficients.

[0030] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages:

[0031] 1. This invention constructs a dual-channel control system of feedforward prediction and feedback compensation by integrating a data acquisition system, a dynamic stabilization platform, a real-time control module, and an additive manufacturing unit within a closed shock-absorbing cabin. The wave radar predicts wave trends 1–2 seconds based on a random wave spectrum model, generating printhead trajectory corrections in advance. The IMU and laser tracker monitor the cabin attitude in real time and fuse the data through Kalman filtering to achieve closed-loop compensation for low-frequency, large displacements. Combined with a six-degree-of-freedom Stewart platform (single-cylinder thrust ≥8kN, response speed 500–1000mm / s, repeatability ±0.03mm), it effectively counteracts disturbances caused by ship roll, pitch, and heave, ensuring continuous stability of the laser-material relative position and molten pool state, thereby achieving millimeter-level precision and high-density metal additive manufacturing under complex sea conditions.

[0032] 2. This invention employs an IP67 double-layer shock-absorbing chamber with a 316L stainless steel shell and a polyurethane sound insulation layer to achieve protection against salt spray, corrosion, and mechanical shock. A seawater-ethylene glycol dual-circulation liquid cooling system combined with a titanium alloy heat exchanger allows for real-time adjustment of the cooling flow rate from 10 to 50 L / min, ensuring stable operation of the laser and control unit at ≤40℃. A redundant power supply consisting of a diesel generator and a lithium battery pack can automatically switch power supply within 10 ms, ensuring long-term continuous operation. This comprehensive environmental protection design ensures stable operation of the system in high-humidity, high-salt, and high-vibration environments such as ocean-going vessels and drilling platforms, reducing maintenance and downtime risks and supporting 24 / 7, long-cycle, unattended manufacturing tasks.

[0033] 3. This invention's additive manufacturing unit combines a cantilever structure, laser ranging, and a floating plate to achieve dynamic correction of the printhead within ±0.1mm and high-frequency vibration isolation. Based on the real-time pose calculation of the Stewart platform, the relative motion speed is automatically adjusted to maintain consistent powder / filament flow rate and layer thickness. The laser scanner detects the geometric error of the printed layer in real time and feeds it back to the control module; if the error exceeds the ±0.1mm threshold, the system automatically pauses and performs a secondary calibration. This multi-level motion-extrusion-geometric detection closed loop ensures the geometric accuracy and metallurgical quality of the printed components, achieving engineering-level quality control for in-situ manufacturing at sea and effectively avoiding defects such as porosity and cracks. Attached Figure Description

[0034] Figure 1 This is a block diagram illustrating the control algorithm principle of an additive manufacturing stabilization support device for marine shipborne equipment, according to an embodiment of the present invention.

[0035] Figure 2 This is an overall schematic diagram of the stable support structure involved in the embodiments of the present invention;

[0036] The components are: 1-Data acquisition system, 2-Dynamic stabilization platform, 3-Additive manufacturing unit, 4-Real-time control module, 5-Environmental adaptation module, and 6-Enclosed shock absorption chamber. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0038] like Figure 1 and Figure 2As shown in the figure, the stable support structure system for marine additive manufacturing proposed in this embodiment includes: a data acquisition system 1, a dynamic stabilization platform 2, an additive manufacturing unit 3, a real-time control module 4, and an environmental adaptation module 5. All equipment is integrated in a closed shock-absorbing chamber 6. The data acquisition system 1 is bidirectionally connected to the real-time control module 4 via an EtherCAT bus; the dynamic stabilization platform 2 is fixed to the bottom load-bearing frame of the shock-absorbing cabin 6 by a group of high-strength bolts; the printing platform base of the additive manufacturing unit 3 is mounted on the dynamic stabilization platform 2, and the height of the base can be flexibly adjusted with the help of the platform. The print head is installed on a telescopic and rotatable cantilever structure, which is fixed to the top of the cabin to ensure that the print head and the cabin remain relatively stationary and achieve synchronous displacement; the real-time control module 4 adopts an industrial-grade embedded system such as NI CompactRIO or dSPACE, runs control algorithms, processes IMU data and generates compensation instructions, with a latency of less than 10ms; the environmental adaptation module 5 includes a liquid cooling system and redundant power supply to prevent overheating of high-power electronic equipment and cope with power supply fluctuations at sea; the shock-absorbing cabin 6 adopts a double-layer composite structure shell with an IP67 standard. The outer layer is a 316L stainless steel welded shell, and the inner layer is a 10mm thick polyurethane foam sound insulation layer.

[0039] In data acquisition system 1: the inertial measurement unit (IMU) has a sampling rate of ≥100Hz and is equipped with a three-axis accelerometer, a three-axis gyroscope and a three-axis magnetometer; the wave radar adopts millimeter-wave radar and predicts the wave motion trend in the next 1-2 seconds through a random wave spectrum model.

[0040] The six-degree-of-freedom dynamic stabilization platform 2 is a Stewart platform structure, including 6 sets of electric servo drive cylinders, with a maximum thrust of ≥8kN per cylinder, a repeatability of ≤±0.03mm, a response speed of 500-1000mm / s, and a carbon fiber telescopic rod with a surface coated with an anti-salt spray corrosion coating.

[0041] The additive manufacturing unit 3 also includes: a laser scanner for real-time monitoring of the geometric error of the printed layer and feedback to the control module; and a telescopic and rotatable cantilever structure to achieve fine-tuning compensation of ±50mm travel and ±0.1mm accuracy of the print head in the scanning direction (X / Y axis plane) and stepping direction (Z axis vertical stacking).

[0042] The control algorithm of the real-time control module 4 includes: feedforward compensation based on wave radar prediction data, generating a pre-correction amount for the printhead trajectory through coordinate transformation; feedback compensation by performing Kalman filtering fusion on IMU data, calculating the platform pose error and converting it into a compensation amount for the magnetic levitation guide rail system through inverse kinematics; and an adaptive PID controller that dynamically adjusts the proportional, integral, and derivative parameters according to the sea state level.

[0043] In the environmental adaptation module 5: the liquid cooling system adopts a seawater-ethylene glycol dual-circulation heat dissipation structure, with a titanium alloy plate heat exchanger installed on the seawater side, and the ethylene glycol solution flow rate adjustable within the range of 10-50 L / min. The redundant power supply system includes a diesel generator and a lithium battery pack, which achieve uninterrupted power switching through a bidirectional DC / AC converter and a static switching module.

[0044] The outer layer of the shock-absorbing chamber is made of 316L stainless steel welded together, and its high strength characteristics resist external impact and mechanical damage; the inner layer is covered with a polyurethane foam sound insulation layer, which effectively isolates noise and absorbs vibration energy.

[0045] Based on any of the above embodiments or combinations of embodiments, in this embodiment, an additive manufacturing stabilization support device suitable for marine shipborne equipment includes a data acquisition system 1, a dynamic stabilization platform 2, an additive manufacturing unit 3, a real-time control module 4, and an environmental adaptation module 5 integrated within a closed shock-absorbing chamber 6.

[0046] The data acquisition system 1 described in this embodiment consists of an inertial measurement unit (IMU), a wave radar, and a laser tracker. The IMU and laser tracker monitor the attitude changes of the shock absorber and provide spatial coordinate feedback for the printhead, respectively. The wave radar system acquires the motion trajectory of the ship platform and the wave spectrum characteristics in real time. The IMU integrates a three-axis accelerometer, gyroscope, and magnetometer, such as the MPU6050 or ADIS16365, to monitor the 6-DOF motion (roll, pitch, heave, etc.) of the shock absorber in real time with a sampling rate of ≥100Hz. The wave radar predicts the wave motion trend for the next 1-2 seconds using millimeter-wave technology, and the laser tracker provides feedback on the spatial coordinates of the printhead with an accuracy of ±0.1mm. All three components transmit attitude, wave spectrum, and position data to the real-time control module via an EtherCAT bus, forming a multi-dimensional motion sensing network. To ensure reliable data transmission, SPI or CAN bus protocols are used instead of RS232 serial communication to improve transmission speed and anti-interference capabilities.

[0047] In this embodiment, the dynamic stabilization platform 2 compensates for vibration displacement through real-time control module commands, providing a stable foundation for the printing system. By introducing flexible displacement adjusters and servo valve-controlled hydraulic jacks, the vibration damping effect and stability can be further improved. Upon receiving control commands, it quickly adjusts its own posture to offset vibrations and displacements caused by ocean waves, creating a stable working environment for the additive manufacturing unit 3. The dynamic stabilization platform adopts a six-degree-of-freedom Stewart structure, with six symmetrically distributed electric servo drive cylinders. Each cylinder has a thrust ≥8kN, and the carbon fiber telescopic rod is coated with an anti-salt spray coating. The response speed reaches 500-1000mm / s, and the repeatability is ≤±0.03mm. It is fixed to the bottom load-bearing frame of the vibration damping chamber by high-strength bolts, and the printing platform of the additive manufacturing unit is mounted on top, achieving low-frequency, large-range motion compensation to offset vibration displacements caused by ocean waves.

[0048] The additive manufacturing unit described in this embodiment uses a Meltio M450 laser-oriented energy deposition printhead. Equipped with a high-power and stable laser energy source and a high-precision coaxial powder / filament feeder, it can precisely control the delivery rate of metal powder or filament, ensuring uniform material deposition. Combined with a multi-axis motion control system, it can flexibly adjust the printhead position and attitude, and operates in a fully inert gas protected environment. A top cantilever structure provides easy maintenance and precise control. To further improve printing accuracy, a laser rangefinder sensor can be added to the cantilever structure to detect real-time positional deviations of the printed model, allowing for fine-tuning through adjustments to the lifting mechanism. Furthermore, a floating plate is added below the printing platform to absorb vibrations generated during printing, thereby reducing the impact on printing accuracy.

[0049] In this embodiment, the real-time control module receives input signals from the data acquisition system and generates control commands for the multi-level compensation execution module and the additive manufacturing execution unit. It employs an industrial-grade embedded system such as NI CompactRIO, running feedforward and feedback compensation with a control latency of <10ms. Feedforward compensation, based on wave prediction data, uses wave motion models such as random wave spectra to generate the platform's expected displacement, adjusting the printhead's target trajectory in advance. Feedback compensation first fuses IMU data using Kalman filtering to calculate the platform's actual pose, then converts the platform pose error into printhead compensation displacement through inverse kinematics calculations. Finally, adaptive PID control dynamically adjusts control parameters based on real-time errors. It supports multi-sensor time synchronization technology to ensure consistency between IMU, laser tracker, and wave radar data, and adapts to sea state changes through adaptive PID dynamic parameter adjustment.

[0050] The environmental adaptation module described in this embodiment includes a seawater-ethylene glycol dual-circulation liquid cooling system (titanium alloy heat exchanger, flow rate 10-50 L / min) and redundant power supplies (seamless switching between diesel generator and lithium battery pack, switching time <10 ms). The IP67-rated double-layer hull uses a 316L stainless steel shell and a 10mm polyurethane sound insulation layer to isolate salt spray corrosion and mechanical impact, ensuring stable operation of the equipment in the high humidity and high salinity environment at sea. The liquid cooling pipeline is connected to the laser heat dissipation vent of the additive manufacturing printing system, effectively removing heat and ensuring stable laser operation. The redundant power supply consists of a diesel generator and a lithium battery pack, which are fixed on both sides of the shock-absorbing chamber and connected to the power supply interfaces of each module through an automatic switching circuit.

[0051] In this embodiment, the dynamic stabilization platform in the shock-absorbing cabin is fixed to the bottom of the cabin, the additive manufacturing unit cantilever structure is installed on the top of the cabin, liquid cooling pipes are distributed along the inner wall and connected to the laser heat dissipation port, and redundant power supplies are distributed on both sides of the cabin and powered by an automatic switching circuit. The data acquisition system and the real-time control module communicate bidirectionally via EtherCAT bus, forming a closed anti-interference working space integrating sensing, control and execution.

[0052] The workflow of the aforementioned marine additive manufacturing stabilization support structure device is as follows:

[0053] Step S1: Connect and debug the data acquisition system, dynamic stabilization platform, additive manufacturing unit, real-time control module, and environmental adaptation module to begin laser additive manufacturing printing. The IMU monitors the three-axis acceleration, angular velocity, and attitude data of the shock absorber in real time at a sampling rate of ≥100Hz. Simultaneously, the wave radar collects the ship's motion trajectory and wave spectrum characteristics, and the laser tracker synchronously acquires the three-dimensional spatial coordinates of the print head. All data is transmitted to the real-time control module via the EtherCAT bus, and a time synchronization protocol is activated to eliminate time lag errors and ensure the spatiotemporal consistency of multi-source sensing data.

[0054] Step S2: Based on the 1-2 second wave motion trend predicted by wave radar, feedforward compensation generates the expected displacement of the platform through a random wave spectrum model and pre-adjusts the trajectory of the print head; feedback compensation performs Kalman filtering fusion on the IMU data, calculates the actual pose deviation of the platform, converts it into the displacement of the print head through inverse kinematics, and uses an adaptive PID controller to dynamically adjust the parameters to adapt to the compensation requirements under different sea conditions.

[0055] Step S3: The dynamic stabilization platform performs compensation. The real-time control module drives the six electric servo cylinders of the six-DOF Stewart platform to adjust the platform posture with a response speed of 500-1000mm / s. The thrust of a single cylinder is ≥8kN. The carbon fiber telescopic rod combined with the anti-salt spray coating offsets low-frequency large-range vibrations and ensures the stability of the printed substrate.

[0056] Step S4: The additive manufacturing units work collaboratively. The telescopic cantilever structure makes fine adjustments to its stroke by ±50mm according to compensation commands. The laser rangefinder sensor corrects the printhead position to an accuracy of ±0.1mm in real time. The floating plate absorbs high-frequency vibrations and synchronously adjusts the material extrusion rate. The laser deposits material under inert gas protection, and the liquid cooling system maintains the heat dissipation temperature ≤40℃.

[0057] Step S5: The liquid cooling system of the environmental adaptation module intelligently adjusts the cooling flow through a dual circulation of seawater and ethylene glycol and a titanium alloy heat exchanger. The redundant power supply achieves seamless switching between the diesel generator and the lithium battery pack within 10ms. The polyurethane sound insulation layer reduces the equipment noise to below 75dB, meeting the requirements of the offshore field operation environment.

[0058] Step S6: Closed-loop quality monitoring and error correction. The laser scanner detects the geometric error of the printed layer in real time and feeds it back to the control module to correct the subsequent trajectory. If the error exceeds the ±0.1mm threshold, the system pauses the operation and starts the secondary calibration of the cantilever structure to ensure printing accuracy and finished product quality. After printing is completed, the instrument is turned off.

[0059] During a voyage, the deck equipment support structure suffered structural damage due to a collision, requiring in-situ repair. The stabilizing support structure described in this patent was hoisted to the vicinity of the damaged area and quickly connected to the pre-installed fixed base on the deck using high-strength bolts via the pre-reserved installation interface at the bottom of the enclosed shock-absorbing chamber 6. The inertial measurement unit (IMU) in the data acquisition system 1 is an ADIS16365, and the wave radar is activated in millimeter-wave scanning mode to monitor the ship's roll, pitch, and wave motion data in real time.

[0060] The real-time control module 4 receives information transmitted from the data acquisition system and predicts the hull sway trend for the next 1.5 seconds using a random wave spectrum model. When the hull roll angle reaches 5° and pitch angle reaches 3°, the feedforward compensation algorithm immediately generates a pre-correction amount for the printhead trajectory. At the same time, the six sets of electric servo drive cylinders of the dynamic stabilization platform respond quickly, with each cylinder adjusting its attitude with a thrust of 7kN, offsetting the sway displacement within 0.3 seconds and keeping the printing platform stable.

[0061] The Meltio M450 printhead in Additive Manufacturing Unit 3 uses a coaxial powder feeding mode to deliver titanium alloy powder. The laser power is set to 3kW, the powder feeding speed is 8g / min, and the scanning speed is 10mm / s. During printing, the laser scanner monitors the printed layer in real time. When a height deviation of 0.2mm is detected in a certain area, the lifting mechanism of the cantilever structure immediately makes fine adjustments to ensure repair accuracy. The seawater-ethylene glycol dual-circulation liquid cooling system in Environmental Adaptation Module 5 operates at a flow rate of 25L / min, stabilizing the laser temperature at 25±2℃. The diesel generator and lithium battery pack seamlessly switch power supply to ensure continuous operation of the equipment. After repair, the test results show that the repair layer density reaches 98%, and the tensile strength reaches 92% of the parent material, meeting the requirements for use on ships.

[0062] At an offshore drilling platform 200 kilometers from shore, a batch of specially sized pipe connectors needed to be urgently manufactured. A stabilizing support structure was installed in the platform's operating area. The outer 316L stainless steel shell of the shock-absorbing chamber protected against sea winds and salt spray corrosion, while the inner polyurethane sound insulation layer reduced equipment operating noise. The data acquisition system acquired platform sway data in real time at a 120Hz sampling rate. When the wave radar predicted an impending surge, the real-time control module activated the feedback compensation mechanism in advance, performing Kalman filtering and fusion on the IMU data, and dynamically adjusting the printhead position through adaptive PID control. The additive manufacturing unit adopted a filament feeding mode, with the printhead cantilever structure adjusting its stroke by ±30mm in the X / Y axis plane and stacking layers with ±0.1mm accuracy in the Z axis direction to complete the manufacturing of complex curved surface connectors. After manufacturing, the connectors underwent flaw detection, and no defects such as porosity or cracks were found. In simulated marine environmental pressure tests, the connectors met the pressure-bearing performance standards, proving that this patented technology can stably produce high-quality components under complex sea conditions.

[0063] Optionally, based on any or a combination of the above embodiments, this embodiment provides a method for achieving high-precision additive manufacturing at sea, including the following steps:

[0064] (1) Data Acquisition and Prediction. Real-time motion and attitude data of the shock-absorbing cabin, wave motion trend data, and real-time position data of the printhead of the additive manufacturing module are acquired. The above data are fused by time synchronization and Kalman filtering to obtain the current precise attitude of the cabin; based on wave radar data and random wave spectrum model, the cabin displacement and attitude changes in the next 1-2 seconds are predicted to form feedforward compensation input.

[0065] (2) Feedforward compensation control. Based on the wave trend prediction, a feedforward compensation algorithm is used to generate a pre-correction amount for the printhead trajectory to offset possible high-frequency micro-vibrations in the future; constrained model predictive control (MPC) is used to optimize the pre-correction trajectory of the printhead to ensure that the compensation amount is smooth and does not exceed the speed and stroke range of the drive cylinder (i.e., actuator) in the dynamic stabilization platform.

[0066] (3) Feedback compensation control. Based on the real-time attitude data and printhead position data fused from the IMU and laser tracker, the pose error of the dynamic stabilization platform is calculated using Kalman filtering and inverse kinematics. Adaptive PID control combined with a linear extended state observer (LESO) is used to suppress sudden external disturbances, thereby achieving real-time compensation for low-frequency large displacements. The feedforward compensation and feedback compensation are synthesized and synchronously sent to the six-degree-of-freedom Stewart platform and the printhead cantilever mechanism to handle low-frequency large-amplitude and medium-to-high-frequency small-amplitude disturbances, respectively.

[0067] (4) Feedback compensation control. Based on the motion state of the dynamic stabilization platform and the relative speed of the printhead, the material volume flow rate is adjusted in real time to ensure that the printed layer thickness meets the following requirements:

[0068]

[0069] Where w(t) is the nozzle width, which is corrected in real time based on the platform tilt angle. The laser power is then adjusted according to the following formula to achieve synergistic effects between volumetric flow rate and heat generation:

[0070]

[0071] The feedforward compensation employs a random wave spectrum frequency-time domain fusion algorithm to generate a six-DOF pose trajectory for the next 1–2 seconds, and considers actuator stroke, velocity, and attitude safety constraints in the MPC optimization. The feedback compensation utilizes an adaptive PID controller to automatically adjust the proportional, integral, and derivative coefficients based on sea state parameters, and employs an anti-integral accumulation strategy when the actuator approaches saturation.

[0072] In the control of synchronous material extrusion, the formula for correcting the runner width is:

[0073] w(t)=w0(1+k α sinα(t)),

[0074] Where w0 is the nominal track width under horizontal attitude, α(t) is the real-time tilt angle, and k α These are empirical calibration coefficients.

[0075] In the above steps, the real-time control system includes a feedforward compensation module, a feedback compensation module, and an adaptive PID control module. The feedforward compensation module generates the expected displacement of the platform based on a random wave spectrum model and wave radar data, and adjusts the target trajectory of the print head in advance. The feedback compensation module uses attitude data fused by Kalman filtering and inverse kinematics calculations to convert the platform's pose error into the compensation displacement of the actuator cylinder. The adaptive PID control module adjusts the control parameters in real time according to the sea state and combines a disturbance observer to suppress sudden disturbances. The dynamic stabilization platform is a six-degree-of-freedom Stewart structure, with six sets of electrically driven servo cylinders symmetrically distributed to offset the low-frequency large displacement caused by sea waves and provide a stable base for the additive manufacturing unit. The additive manufacturing unit includes a laser-directed energy deposition print head, a coaxial powder / filament feeding device, a top cantilever structure, and a laser rangefinder. The cantilever structure has a lifting mechanism with a stroke of ±50mm, which can finely adjust the print head position in real time with an accuracy of ±0.1mm. A floating damping plate is set below it to absorb high-frequency vibrations, and the metal pool deposition is completed in a fully inert gas protected environment. The line quality inspection and automatic fault recovery unit includes a laser scanner and a surface geometric error detection algorithm, which is used to detect the printing layer thickness and geometric deviation in real time. When the deviation exceeds 0.1mm, the system is automatically paused and the cantilever structure is driven to perform secondary calibration.

[0076] Preferably, in this invention, a method of multi-source real-time data acquisition and synchronous fusion is adopted to give all collected real-time data a unified timestamp and establish a circular buffer on the controller side to ensure orderly arrival.

[0077] Preferably, in this embodiment, feedforward is used to eliminate foreseeable disturbances (high-frequency micro-vibrations + partial mid-frequency trends), feedback is used to eliminate residual errors (low-frequency large displacements + unmodeled disturbances), and the synthetic compensation is mapped onto the Stewart six-degree-of-freedom platform and the printhead trajectory.

[0078] In the feedforward compensation module, a random wave spectrum model is established using the spectral parameters output by the wave radar as input to generate the prior posture of the hull for the future Δt = 1~2s. For example, the PM / JONSWAP spectral parameters are used to generate the prior posture for the future Δt = 1~2s:

[0079] More specifically, the dominant frequency family {ω} of the platform disturbance is obtained based on the wave spectrum (wave motion trend data). i} and amplitude {A i Construct a perturbation prior:

[0080]

[0081] In the formula, A i ,ω i ,φ iLet be the amplitude, angular frequency, and initial phase of the i-th harmonic component, respectively; Δt be the prediction time-domain window; and ξ be the platform pose. Pose prior trajectory.

[0082] Let the nominal trajectory of the print head be... Then feedforward correction:

[0083]

[0084] Among them, T BH The Jacobian / homogeneous matrix is ​​used to transfer the pose from the cabin to the print head coordinates.

[0085] Solve the constrained model predictive control over the N-step prediction domain, and As a perturbation prediction, the cost function is:

[0086]

[0087] In the formula, For nominal path, For the feedforward correction path, T BH e is the pose mapping matrix from the cabin to the print head. k+j The trajectory error at step k+j is given, where Q and R are cost weights, and Δu is the control increment. The optimal advance correction amount is determined while satisfying constraints such as cylinder speed and stroke.

[0088] In the feedback compensation module, a linear extended state observer (LESO) is introduced to estimate the unmodeled disturbance d(t), and a compensation of -d is added to the control law. ^ (t), improving the ability to suppress low-frequency large displacements and sudden impacts. Specifically, firstly, a mapping between error and inverse kinematics is constructed:

[0089] e ξ (t)=ξ(t)-ξ ref (t),Δl=J -1 (ξ)e ξ

[0090] in, Let J be the length increment of the six actuator cylinders, and J be the Jacobian matrix of the Stewart platform. Then the adaptive PID control model is:

[0091]

[0092] Where ρ represents sea state intensity indices (such as significant wave height, wave crest frequency, and roll / pitch RMS); additional wind resistance enhancement component:

[0093]

[0094] To prevent actuator saturation from causing integral divergence.

[0095] Based on any or a combination of the above embodiments, in this embodiment, the speed of the printhead in the chamber system is set to v. H The velocity of the workpiece / platform within the cabin system is v. B Then, the path speed relative to the workpiece is:

[0096] v path (t)=||v H (t)-v B (t)||

[0097] This value is directly entered into the above formula to set. This allows it to automatically adapt to the platform's instantaneous movements.

[0098] The effect of attitude tilt angle α on molten pool spreading can be empirically corrected:

[0099] w(t)=w0(1+k α sinα(t)), |α|<<π / 2

[0100] Where w0 is the nominal width k under horizontal attitude. α These are calibration coefficients.

[0101] To maintain the geometric stability of the molten pool, the laser power PL(t) and the volumetric flow rate are... Collaboration:

[0102]

[0103] κ is the empirical slope (calibrated by material / powder feeding efficiency), and the liquid cooling system ensures the laser's operating temperature window.

[0104] Preferably, in this embodiment, an online layer thickness feedback and fine-tuning method is also provided, specifically as follows: the height of the deposited layer is obtained by laser ranging / surface scanning. To correct layer thickness errors, fine-tune the outer ring PI configuration:

[0105]

[0106] when|e h |>∈ h If the surface geometric error is greater than 0.1 mm, a pause and secondary calibration will be triggered.

[0107] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A stable support structure system suitable for marine additive manufacturing, characterized in that, It includes a closed shock-absorbing chamber (6) and a dynamic stabilization platform (2) located within the closed shock-absorbing chamber (6), a data acquisition system (1), a dynamic stabilization platform (2), an additive manufacturing unit (3), and a real-time control module (4), wherein, The dynamic stabilization platform (2) includes a six-degree-of-freedom Stewart structure for keeping the workpiece to be printed horizontal; The additive manufacturing unit (3) includes a laser printhead and a three-axis motion module for driving the laser printhead to move; The data acquisition system (1) is used to acquire in real time the motion and attitude data of the enclosed shock absorber (6), the wave motion trend data, and the printhead position data of the additive manufacturing module (3); The real-time control module (4) generates a pre-correction amount for the printhead trajectory using a feedforward compensation module based on the wave motion trend data, in order to correct the high-frequency micro-vibrations of the additive manufacturing module (3). At the same time, based on the real-time motion and attitude data of the shock-absorbing chamber and the printhead position data, the feedback compensation module corrects the position and posture error of the dynamic stabilization platform (2), in order to compensate for the low-frequency large displacement motion of the dynamic stabilization platform (2), and synchronously adjusts the material extrusion rate of the printhead according to the motion state of the dynamic stabilization platform (2), so that the thickness of the printed layer remains consistent.

2. A stable support structure system suitable for marine additive manufacturing according to claim 1, characterized in that, The data acquisition system (1) includes an inertial measurement unit, a wave radar and a laser tracker. The inertial measurement unit, the wave radar and the laser tracker transmit the motion and attitude data of the enclosed shock-absorbing chamber (6), the wave motion trend data and the print head position data to the real-time control module (4) through the EtherCAT bus, and communicate using the SPI or CAN bus protocol. Preferably, the inertial measurement unit integrates a triaxial accelerometer, a gyroscope, and a magnetometer.

3. A stable support structure system suitable for marine additive manufacturing according to claim 1, characterized in that, The dynamic stabilization platform (2) includes a six-degree-of-freedom Stewart structure, which includes an upper platform, a lower platform, and six sets of electric servo drive cylinders. The upper platform is connected to the upper end of the six sets of electric servo drive cylinders via ball joints or Hooke joints. The lower platform serves as a fixed base and is fixed to the load-bearing frame at the bottom of the enclosed shock-absorbing chamber (6) via a set of high-strength bolts. The lower platform is connected to the lower end of the six sets of electric servo drive cylinders. The six sets of electric servo drive cylinders are symmetrically distributed between the upper platform and the lower platform.

4. A stable support structure system suitable for marine additive manufacturing according to claim 1, characterized in that, The feedforward compensation module includes an optimization calculation unit based on constraint model predictive control, which generates a smooth and unsaturated printhead advance correction trajectory while meeting the safety limits of the stroke, speed, and attitude of the electric servo drive cylinder that executes the six-degree-of-freedom Stewart structure.

5. A stable support structure system suitable for marine additive manufacturing according to claim 1, characterized in that, The additive manufacturing unit synchronously adjusts the material extrusion flow rate through the following relationship. Where h(t) is the printing layer thickness, w(t) is the track width corrected in real time according to the tilt angle of the dynamic stabilization platform (2), and v path (t) represents the instantaneous relative velocity between the printhead and the dynamic stabilization platform (2).

6. A stable support structure system suitable for marine additive manufacturing according to any one of claims 1, characterized in that, It also includes an environmental adaptation module (5), which includes a seawater-ethylene glycol dual-cycle liquid cooling unit and a redundant power supply.

7. An additive manufacturing method suitable for marine shipboard equipment, characterized in that, Includes the following steps: Step 1: Obtain real-time motion and attitude data of the shock absorber, wave motion trend data, and printhead position data of the additive manufacturing module (3) at the current moment; Step 2: Based on the wave motion trend data, a feedforward compensation algorithm is used to generate a pre-correction amount for the printhead trajectory in order to correct the high-frequency micro-vibration of the additive manufacturing module (3). At the same time, based on the real-time motion and attitude data of the shock absorber and the printhead position data at the current moment, a feedback compensation algorithm is used to correct the pose error of the dynamic stabilization platform (2) in order to compensate for the low-frequency large displacement motion of the dynamic stabilization platform (2). Step 3: Adjust the material extrusion rate of the print head synchronously according to the motion state of the dynamic stabilization platform (2) to keep the thickness of the printed layer consistent.

8. The additive manufacturing method for marine equipment according to claim 7, characterized in that, Step two, which involves generating a pre-correction amount for the printhead trajectory using a feedforward compensation algorithm based on the wave motion trend data, includes the following steps: (21) Based on the wave motion trend data, the dominant frequency family and amplitude of the platform disturbance are obtained, the hull disturbance prior is constructed, and the future [t] is generated based on the hull disturbance prior. k , t k Prior trajectory of printhead pose within the time interval +Δt] (22) Based on the expected trajectory of the print head and the prior pose trajectory The difference is used to generate a pre-correction amount for the printhead trajectory to correct the high-frequency micro-vibrations of the additive manufacturing module (3); (23) The pre-correction trajectory of the printhead is optimized by using a constraint model predictive control to ensure that the compensation amount is smooth and does not exceed the speed and travel range of the dynamic stable platform (2).

9. The additive manufacturing method for marine equipment according to claim 8, characterized in that, In step three, based on the motion state of the dynamic stabilization platform and the relative velocity v of the print head... path (t), real-time adjustment of material volumetric flow rate Make the printed layer thickness h(t) satisfy: Where w(t) is the nozzle width that is corrected in real time based on the platform tilt angle.

10. The additive manufacturing method for marine equipment according to claim 9, characterized in that, The correction formula for the nozzle width w(t) is: w(t)=w0(1+k α sinα(t)), w0 is the nominal track width under horizontal attitude, α(t) is the real-time tilt angle, and k α These are empirical calibration coefficients.

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