Rocket storage tank bottom laser welding system and welding method

Abstract

The invention provides a rocket storage tank bottom laser welding system and method. The rocket storage tank bottom laser welding system comprises a cutting control panel, a guide rail, a welding control panel, an RGV, a storage tank bottom, a welding robot and a measuring and cutting robot. The welding robot and the measuring and cutting robot are respectively arranged on one side of the guide rail; the welding robot body is used for driving the first optical fiber laser to move synchronously with the welding head and performing welding operation of a circular seam and a longitudinal seam on the bottom of the storage tank; and the measuring and cutting robot body is used for driving the second fiber laser and the cutting head to move synchronously, measuring X, Y and Z positioning coordinate data of the bottom of the storage box and controlling the cutting head to cut the allowance of a circular seam and a longitudinal seam of the bottom of the storage box. According to the system, laser measurement, intelligent cutting and precise welding are integrated, and the welding quality, precision and efficiency of the bottom of the rocket storage tank are comprehensively improved.

Description

Technical Field

[0001] This invention relates to the field of intelligent welding technology, and in particular to a laser welding system and welding method for the bottom of a rocket propellant tank. Background Technology

[0002] As a core structural component of launch vehicles, the manufacturing quality of rocket propellant tanks directly affects the success or failure of the entire flight mission. The tank bottom (or simply tank bottom), a critical load-bearing component, is typically ellipsoidal or hemispherical, making its welding quality paramount. However, current manufacturing practices have revealed numerous technical bottlenecks in traditional rocket propellant tank bottom welding techniques, severely hindering the industry's efficient and high-quality development.

[0003] First, traditional welding methods heavily rely on manual operation by skilled workers, making it difficult to guarantee consistent weld quality. Bottom welds, especially those involving the segmented joints and the circumferential seams between the front and rear bottoms and the segments, often involve complex spatial curves. The welding process heavily depends on the welder's personal experience and on-site condition, introducing human uncertainty in aspects such as welding parameter control and the uniformity of torch movement. This results in significant differences in internal quality (e.g., porosity, slag inclusions, incomplete penetration), mechanical properties, and appearance between different batches and even different welds within the same propellant tank, posing a potential threat to the rocket's structural reliability. Welds are like the rocket's "lifeline," and their consistent quality is the cornerstone of its safety.

[0004] Secondly, there is a lack of effective control over thermal deformation during the welding process. Welding is a process of rapid localized heating followed by cooling, which inevitably generates uneven thermal stress within the component, leading to unpredictable shrinkage and warping of the bottom of the box. Existing technologies often rely on post-weld correction or prevention through preset anti-deformation amounts, but lack a mechanism for real-time, online monitoring and feedback of deformation during the welding process. Because the actual occurrence of deformation cannot be "sensed," the welding system cannot perform adaptive path and parameter compensation, resulting in decreased assembly accuracy and even affecting the fatigue life of the product due to excessive residual stress.

[0005] Secondly, the automated tracking and precise positioning accuracy of complex curved surface welds is insufficient. Although automated welding equipment has been applied, it generally suffers from problems of "inaccurate tracking" and "unable to keep up" when dealing with complex curved surface welds on large, weakly rigid box bottoms. The combined effects of tooling positioning errors, thermal deformation during welding, and the robot's own absolute positioning errors cause the welding torch to frequently deviate from the preset ideal weld trajectory. This deviation directly results in weld offset, undercut, and incomplete penetration, affecting the load-bearing capacity of the welded joint.

[0006] Finally, in view of the above factors, the traditional manufacturing mode has low production efficiency and cannot meet the batch demand of commercial aerospace. Over-reliance on skilled workers, large welding qualification rate fluctuation, high rework rate and long production cycle make the manufacturing cost of a single tank high. This is seriously deviated from the core demand of commercial aerospace, which is high reliability, low cost, rapid iteration and large-scale manufacturing, and has become one of the key obstacles restricting the breakthrough of the commercial aerospace industry.

[0007] In summary, it is an urgent major issue in the field of aerospace manufacturing to break through the traditional welding mode characterized by "manual guidance and experience driving" and develop new manufacturing technology with intelligence, digitization and automation as the core, so as to realize the leap from "skill" to "science" in the welding of the tank bottom of the rocket tank. SUMMARY

[0008] The rocket tank bottom laser welding system and welding method provided by the application effectively solve the above technical problems by constructing an automatic system integrating laser measurement, intelligent cutting and precise welding, and comprehensively improve the welding quality, precision and efficiency of the rocket tank bottom.

[0009] The application provides a rocket tank bottom laser welding system, which comprises: a cutting control panel, a guide rail, a welding control panel, an RGV vehicle, a tank bottom, a welding robot and a measurement and cutting robot. The guide rail is an RGV guide rail system, comprising a linearly laid guide rail body and an RGV vehicle mounted on the guide rail body; the tank bottom is fixed on the RGV vehicle; the welding control panel is used for interaction between the laser welding robot and the operator, and stores the parameter settings and welding process parameter settings of the laser welding robot input by the operator. The welding robot and the measurement and cutting robot are arranged on one side of the guide rail. The welding robot and the measurement and cutting robot are both high-rigidity 6-axis industrial robots; the welding robot comprises a welding robot body, a first fiber laser, a welding head, a first cooling system and a first auxiliary gas system; the first fiber laser and the welding head are arranged on the mechanical arm of the welding robot body; the first cooling system is used for directly cooling the welding head; the first auxiliary gas system is used for providing pneumatic driving power for the welding robot body; the welding robot body is used for synchronous movement with the first fiber laser and the welding head, and performs welding operation of the ring seam and the longitudinal seam on the tank bottom. The measurement cutting robot comprises a measurement cutting robot body, a second fiber laser, a cutting head, a second cooling system and a second auxiliary gas system; the second fiber laser and the cutting head are arranged on a mechanical arm of the measurement cutting robot body; the second cooling system is used for directly cooling the cutting head; the second auxiliary gas system is used for providing pneumatic driving power for the measurement cutting robot body; the measurement cutting robot body is used for synchronously moving with the second fiber laser and the cutting head, and performing measurement of X, Y and Z positioning coordinate data of the tank bottom and control of cutting allowance operation of the ring seam and the longitudinal seam of the tank bottom by the cutting head.

[0010] Preferably, as an implementable mode, the system further comprises a nitrogen gas tank and a pressure stabilizing tank; the nitrogen gas tank is a container for storing nitrogen gas; the pressure stabilizing tank is used for pressure stabilizing operation of nitrogen gas in the tank; one end of the pressure stabilizing tank is in communication with the nitrogen gas tank, and the other end of the pressure stabilizing tank is in communication with the first auxiliary gas system and the second auxiliary gas system respectively.

[0011] Preferably, as an implementable mode, the rocket tank bottom laser welding system further comprises a welding control cabinet group and a laser welding control cabinet group; the welding control cabinet group is used for receiving control instructions input by an operator, and performing control operation on the welding robot according to the control instructions; the laser welding control cabinet group is used for controlling the first fiber laser, the welding head, the first cooling system and the first auxiliary gas system of the welding robot.

[0012] Preferably, as an implementable mode, the rocket tank bottom laser welding system further comprises a welding cooling cabinet group; the welding cooling cabinet group is used for performing cooling operation on the welding head.

[0013] Preferably, as an implementable mode, the rocket tank bottom laser welding system further comprises a cutting control cabinet group and a laser cutting control cabinet group; the cutting control cabinet group is used for receiving control instructions input by an operator, and performing control operation on the measurement cutting robot according to the control instructions; the laser cutting control cabinet group is used for controlling the second fiber laser, the cutting head, the second cooling system and the second auxiliary gas system of the measurement cutting robot.

[0014] Preferably, as an implementable mode, the rocket tank bottom laser welding system further comprises a cutting cooling cabinet group; the cutting cooling cabinet group is used for performing cooling operation on the cutting head by a circulating water cooling system (i.e. the circulating water cooling system is a PID temperature control cold water machine).

[0015] Preferably, as an implementable manner; the cutting cooling cabinet group is used for collecting the temperature of the current cutting head in real time when the cooling action is performed on the current cutting head, and if the current temperature exceeds the preset high warning temperature, the PID temperature closed loop control circulating water cooling system is used to perform the overheating cooling processing operation on the welding head.

[0016] Preferably, as an implementable manner; the rocket tank bottom laser welding system further comprises an RGV vehicle remote controller; the RGV vehicle remote controller is used for controlling the RGV vehicle to perform speed control, forward control, backward control, and ascending control, descending control, rotating control, starting control, stopping control and reset control actions.

[0017] Preferably, as an implementable manner; the rocket tank bottom laser welding system further comprises a hydraulic and pneumatic system and a shielding gas control cabinet group; the hydraulic and pneumatic system is used for circulating air to control pneumatic valves; the hydraulic and pneumatic system comprises air cylinders, pneumatic valves, flow sensors, pneumatic control devices and pipelines; the shielding gas control cabinet group is used for controlling the pneumatic control devices.

[0018] The present application provides a rocket tank bottom laser welding method, which utilizes the rocket tank bottom laser welding system to perform welding control operation, comprising the following operation steps: Step S1, the system first performs a self-checking program, checks whether the welding robot, the measuring cutting robot, the hydraulic and pneumatic system and the shielding gas control cabinet group have alarm information, checks whether the welded workpiece is in place, and prepares for the next step; Step S2, control the current program to enter the second fiber laser of the measuring cutting robot body, perform 3D scanning of the tank bottom to obtain a laser point cloud image of the tank bottom, compare the laser point cloud image with a preset point cloud image model, determine whether the similarity of the laser point cloud image of the current tank bottom exceeds a first standard threshold, if the determination is qualified, if not, the determination is unqualified, and control the cutting head to perform laser cutting operation to remove the excess, until the next step is qualified; the measuring cutting robot body, the second fiber laser, the cutting head, the second cooling system, the second auxiliary gas system; the second fiber laser and the cutting head are arranged on the mechanical arm of the measuring cutting robot body; the second cooling system is used for directly cooling the cutting head Step S3, control the current program to enter the welding robot, first control the welding head of the welding robot to perform longitudinal seam welding operation on the current tank bottom, after the longitudinal seam welding is completed, prepare for the next step; Step S4, control the current program to enter the second fiber laser of the measurement cutting robot body, re-perform the 3D scanning of the tank bottom to obtain the laser point cloud image of the tank bottom, compare the laser point cloud image with the standard longitudinal seam of the preset point cloud image model, judge whether the similarity of the longitudinal seam of the current laser point cloud image of the tank bottom exceeds the second standard threshold, if yes, if no, it is determined that it is unqualified, and control the cutting head to start the laser cutting operation to remove the excess until the next step is performed. Step S5, control the current program to enter the welding robot, control the welding head of the welding robot to perform the circular seam welding operation on the current tank bottom, and after the circular seam welding is completed, the next step is prepared. Step S6, control the current program to enter the second fiber laser of the measurement cutting robot body, re-perform the 3D scanning of the tank bottom to obtain the laser point cloud image of the tank bottom, compare the laser point cloud image with the standard circular seam of the preset point cloud image model, judge whether the similarity of the circular seam of the current laser point cloud image of the tank bottom exceeds the third standard threshold, if yes, if no, it is determined that it is unqualified, and control the cutting head to start the laser cutting operation to remove the excess until the next step is performed. Step S7, control the program to end.

[0019] The technical scheme provided by the embodiment of the present application can include the following beneficial effects: The present application discloses a kind of rocket tank bottom laser welding method, by multiple robot cooperation and closed loop control, realize tank bottom welding whole process automation, greatly improve production efficiency and consistency;At the same time, it provides the processing procedure and step of online measurement and self-adaptive correction, can effectively compensate thermal deformation and assembly error, improve weld quality. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is the overall architecture schematic principle display graph of a kind of rocket tank bottom laser welding system of the present application; Figure 2 It is the display graph of RGV car remote controller in a kind of rocket tank bottom laser welding system of the present application; Figure 3 It is the flow chart of a kind of rocket tank bottom laser welding method of the present application.

[0021] Label: cutting control panel 1;Guide rail 2;Welding control panel 3;RGV car 4;Tank bottom 5;Welding robot 6;Welding control cabinet group 7;Laser welding control cabinet group 8;Welding cooling cabinet group 9;Protective gas control cabinet group 10;Nitrogen gas tank 11;Pressure stabilizing tank 12;Cutting control cabinet group 13;Laser cutting control cabinet group 14;Cutting cooling cabinet group 15;Measurement cutting robot 16. DETAILED DESCRIPTION

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0024] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Example 1 like Figure 1 As shown, Embodiment 1 of the present invention provides a laser welding system for the bottom of a rocket propellant tank, comprising: a cutting control panel 1, a guide rail 2, a welding control panel 3, an RGV vehicle 4, the bottom of the propellant tank 5, a welding robot 6, a welding control cabinet assembly 7, a laser welding control cabinet assembly 8, a welding cooling cabinet assembly 9, a protective gas control cabinet assembly 10, a nitrogen cylinder 11, a pressure stabilizing tank 12, a cutting control cabinet assembly 13, a laser cutting control cabinet assembly 14, a cutting cooling cabinet assembly 15, and a measuring and cutting robot 16; It should be noted that the aforementioned laser welding system for the rocket propellant tank bottom mainly consists of a cutting control panel 1, guide rail 2, welding control panel 3, RGV vehicle 4, propellant tank bottom 5, welding robot 6, welding control cabinet assembly 7, laser control cabinet assembly 8, welding cooling cabinet assembly 9, protective gas control cabinet assembly 10, gas tank 11, pressure stabilizing tank 12, cutting control cabinet assembly 13, laser control cabinet assembly 14, cutting cooling cabinet assembly 15, and measuring and cutting robot 16, etc., as detailed below. Figure 1 : The guide rail 2 is an RGV guide rail system, including a linearly laid guide rail body and an RGV vehicle 4 mounted and fixed on the guide rail body (i.e. the RGV vehicle is used to carry and position the tank bottom, so that it sequentially flows between the measuring station, the cutting station and the welding station); the tank bottom 5 is fixed on the RGV vehicle 4; the welding control panel 3 is used for the laser welding robot to interact with the operator, and stores the parameter settings and welding process parameter settings input by the operator for the laser welding robot; The welding robot 6 and the measuring and cutting robot 16 are respectively arranged on one side of the guide rail 2; The welding robot 6 and the measuring and cutting robot 16 are both 6-axis industrial robots with high rigidity; the welding robot 6 (including a welding robot body, a first fiber laser, a welding head, a first cooling system and a first auxiliary gas system; the first fiber laser and the welding head are arranged on the mechanical arm of the welding robot body) is used to synchronously move with the first fiber laser and the welding head, and perform the welding operation of the girth seam and the longitudinal seam of the tank bottom 5; The measuring and cutting robot 16 (including a measuring and cutting robot body, a second fiber laser, a cutting head, a second cooling system and a second auxiliary gas system; the second fiber laser and the cutting head are arranged on the mechanical arm of the measuring and cutting robot body) is used to synchronously move with the second fiber laser and the cutting head, and perform the operation of measuring the X, Y and Z positioning coordinate data of the tank bottom 5 and controlling the cutting head to cut the girth seam and the longitudinal seam of the tank bottom 5; In addition, the system architecture of the rocket tank bottom laser welding system is arranged as follows: The cutting control panel 1 is used for the laser cutting robot to interact with the operator, the robot parameter setting and the cutting process parameter setting, etc. Guide rail 2: the RGV vehicle cooperates with the above guide rail 2; the guide rail of the RGV is the core infrastructure of the automatic logistics, and the straightness error and the levelness error of the guide rail in the full length range must be strictly controlled (usually required to be within ±1mm), otherwise it will cause the RGV to deviate, the wheel to be severely worn, and abnormal noise and vibration to be generated. It is used to mount and fix the RGV vehicle; The welding control panel 3 is used for the laser welding robot to interact with the operator, the robot parameter setting and the welding process parameter setting, etc. The RGV vehicle 4, i.e. the RGV, is the English full name of Rail Guided Vehicle, which means "rail guided vehicle" or "rail shuttle vehicle" in Chinese. It is an automatic handling trolley running on a pre-set fixed track. It is used for tank bottom station conversion and transportation, can realize the functions of tank bottom rotation and lifting, and has an independent remote controller.

[0026] The rocket propellant tank bottom, or the dome-shaped structure at the "bottom" and "top" of a rocket fuel tank (such as a liquid oxygen tank, liquid hydrogen tank, or kerosene tank), is not only a container for the propellant but also a crucial part of the load-bearing structure. The workpiece being welded is part of the rocket propellant tank. The welding robot 6 is a high-precision, high-rigidity 6-axis industrial robot. Laser welding requires extremely high path accuracy and repeatability within ±0.1mm, which ordinary handling robots cannot meet. Its main task is to weld the circumferential and longitudinal seams on the bottom of the storage tank while the laser head moves. Nitrogen cylinder 11: A container for storing nitrogen. Pressure stabilizing tank 12: Ensures stable nitrogen pressure; Cutting Control Cabinet Group 13: In modern laser cutting, the cutting control cabinet group is the command center, power distribution center, and data processing core of the entire system. It is no longer a single-function cabinet, but a modular mechatronic system that integrates CNC, drive, power, cooling, and management functions, serving as the core hub connecting the cutting robot and the operator; Laser Cutting Control Cabinet Unit 14: The laser cutting control cabinet unit is a highly complex system engineering project integrating optics, mechanics, electronics, computing, and heat. It is not only the core value of industrial laser equipment, but also a concentrated embodiment of comprehensive strength in high-power laser technology, precision CNC technology, and high-end equipment manufacturing, having a profound impact on national defense security and the development of strategic industries. It is used to arrange welding lasers, controllers, electrical components, etc. Cutting Cooling Cabinet Unit 15: The cutting cooling cabinet unit is a crucial and indispensable auxiliary system. While it doesn't typically participate directly in the welding process, it's key to ensuring welding quality and protecting expensive core equipment. It's used for cooling the welding laser, implementing PID temperature closed-loop control to prevent damage to the welding torch, laser welding head, and welding power supply due to overheating, significantly extending their service life. Measurement and Cutting Robot 16: This high-precision, high-rigidity 6-axis industrial robot is used. Laser cutting requires extremely high path accuracy and repeatability within ±0.1mm, which ordinary handling robots cannot meet. Its main tasks are to measure the X, Y, and Z coordinate data of the tank bottom and to cut the circumferential and longitudinal seams of the tank bottom. In the above specific technical solution, the nitrogen tank 11 is a container for storing nitrogen; the pressure stabilizing tank 12 is used to stabilize the pressure of the nitrogen in the nitrogen tank 11; one end of the pressure stabilizing tank 12 is connected to the nitrogen tank 11, and the other end of the pressure stabilizing tank 12 is connected to the first auxiliary gas system and the second auxiliary gas system respectively.

[0027] In the above specific technical scheme, the system further comprises a welding control cabinet group 7 and a laser welding control cabinet group 8; the welding control cabinet group 7 is used for receiving control instructions input by an operator and performing control operations on the welding robot 6 according to the control instructions; and the laser welding control cabinet group 8 is used for controlling a first fiber laser, a welding head, a first cooling system and a first auxiliary gas system of the welding robot.

[0028] It should be noted that the welding control cabinet group 7: In the field of industrial automation, the control cabinet is the "nerve center" and "powerful heart" of the whole system. It is not a simple box, but a professional device integrating various electrical and electronic components according to specific functional requirements. It is the core hub connecting the welding robot and the operator; the laser welding control cabinet group 8: The laser welding control cabinet group is a highly complex system engineering integrating light, machine, electricity, calculation and heat. It is not only the value core of industrial laser equipment, but also the embodiment of comprehensive strength in the field of high-power laser technology, precision numerical control technology and high-end equipment manufacturing, which has a profound impact on national defense security and strategic industry development. It is used for arranging welding lasers, controllers, electrical components, etc. In the above specific technical scheme, the system further comprises a welding cooling cabinet group 9; the welding cooling cabinet group 9 is used for performing cooling actions on the welding head.

[0029] In the above specific technical scheme, the system further comprises a cutting control cabinet group 13 and a laser cutting control cabinet group 14; the cutting control cabinet group 13 is used for receiving control instructions input by an operator and performing control operations on the measuring cutting robot according to the control instructions; and the laser cutting control cabinet group 14 is used for controlling a second fiber laser, a cutting head, a second cooling system and a second auxiliary gas system of the measuring cutting robot 16.

[0030] The cutting control cabinet group 13: In modern laser cutting, the cutting control cabinet group is the command center, power distribution center and data processing core of the whole system. It is no longer a single-function cabinet, but a modular mechatronic system integrating numerical control, drive, power, cooling and management functions, which is the core hub connecting the cutting robot and the operator; the laser cutting control cabinet group 14: The laser cutting control cabinet group is a highly complex system engineering integrating light, machine, electricity, calculation and heat. It is not only the value core of industrial laser equipment, but also the embodiment of comprehensive strength in the field of high-power laser technology, precision numerical control technology and high-end equipment manufacturing, which has a profound impact on national defense security and strategic industry development. It is used for arranging welding lasers, controllers, electrical components, etc. In the specific technical scheme, the system further comprises a cutting cooling cabinet group 15; the cutting cooling cabinet group 15 is used for performing a cooling action on the cutting head through a circulating water cooling system (i.e., the circulating water cooling system is a PID temperature control cold water machine). When the cooling action is performed on the current cutting head, the cutting cooling cabinet group 15 is used for collecting the temperature of the current cutting head in real time, and if the current temperature exceeds a preset high warning temperature, the PID temperature closed-loop control circulating water cooling system is used to perform an overheating cooling processing operation on the welding head.

[0031] Referring to Figure 2 , Figure 2 The RGV vehicle remote controller is used to control the RGV vehicle to perform speed control, forward control, backward control, and ascending control, descending control, rotating control, starting control, stopping control and reset control actions.

[0032] In the specific technical scheme, the system further comprises a hydraulic and pneumatic system and a protective gas control cabinet group; the hydraulic and pneumatic system is used for circulating air to control pneumatic valves; the hydraulic and pneumatic system comprises a gas cylinder, pneumatic valves, a flow sensor, pneumatic control devices and pipelines; and the protective gas control cabinet group is used for controlling the pneumatic control devices.

[0033] The main use of the rocket tank bottom laser welding system provided by the embodiment one is a special device for laser welding of a tank bottom ring seam and a longitudinal seam. The system mainly comprises a robot execution main body, a pneumatic system (i.e., a hydraulic or pneumatic power source), an electric control system (controlling the robot execution action), a measurement function (the robot realizes measurement), an image monitoring system, a remote controller, an auxiliary system and other accessories. The rocket tank bottom is a welded part, and the tank bottom is an important part of the rocket tank. The image monitoring system is responsible for monitoring the whole production process to ensure safe production and high-reliability product quality. The monitoring system adopts a Hikvision monitoring camera with a 4 million 2K high-definition full-color night vision voice intercom, is dustproof and waterproof, supports two light supplement modes of white light and infrared, and can switch the working mode through a Hikvision interconnection APP.

[0034] Embodiment two The rocket tank bottom laser welding method provided by the application utilizes the rocket tank bottom laser welding system to perform welding control operations, and comprises the following operation steps: Step S1, the system first performs a self-checking program to check whether the welding robot, the measurement cutting robot, the hydraulic and pneumatic system and the protective gas control cabinet group have alarm information, and checks whether the welded workpiece is in place to prepare for the next step. Step S2, control the current program to enter the second fiber laser of the measuring cutting robot body, perform 3D scanning of the tank bottom to obtain a laser point cloud image of the tank bottom, compare the laser point cloud image with a preset point cloud image model, determine whether the similarity of the laser point cloud image of the current tank bottom exceeds a first standard threshold (i.e., a basic similarity threshold), if it is determined to be qualified, if it is not, it is determined to be unqualified, and control the cutting head to start laser cutting operation to remove excess until the next step is qualified; the measuring cutting robot body, the second fiber laser, the cutting head, the second cooling system, and the second auxiliary gas system; the second fiber laser and the cutting head are arranged on the mechanical arm of the measuring cutting robot body; the second cooling system is used to directly cool the cutting head Step S3, control the current program to enter the welding robot, first control the welding head of the welding robot to perform longitudinal seam welding operation on the current tank bottom, and after the longitudinal seam welding is completed, prepare for the next step; Step S4, control the current program to enter the second fiber laser of the measuring cutting robot body, re-perform 3D scanning of the tank bottom to obtain a laser point cloud image of the tank bottom, compare the laser point cloud image with a standard longitudinal seam of a preset point cloud image model, determine whether the similarity of the longitudinal seam of the laser point cloud image of the current tank bottom exceeds a second standard threshold (i.e., a longitudinal seam standard threshold), if it is determined to be qualified, if it is not, it is determined to be unqualified, and control the cutting head to start laser cutting operation to remove excess until the next step is qualified; Step S5, control the current program to enter the welding robot, control the welding head of the welding robot to perform ring seam welding operation on the current tank bottom, and after the ring seam welding is completed, prepare for the next step; Step S6, control the current program to enter the second fiber laser of the measuring cutting robot body, re-perform 3D scanning of the tank bottom to obtain a laser point cloud image of the tank bottom, compare the laser point cloud image with a standard ring seam of a preset point cloud image model, determine whether the similarity of the ring seam of the laser point cloud image of the current tank bottom exceeds a third standard threshold (i.e., a ring seam standard threshold), if it is determined to be qualified, if it is not, it is determined to be unqualified, and control the cutting head to start laser cutting operation to remove excess until the next step is qualified; Step S7, control the program to end.

[0035] The application provides a rocket tank bottom laser welding method, which utilizes the rocket tank bottom laser welding system to perform welding control operation, and adopts high-precision robot cooperation and RGV precise conveying system. The application provides a rocket tank bottom laser welding method, which aims at the technical problem of insufficient positioning precision of complex curved surface welding seams, deploys a laser measuring system composed of a structured light measuring device and a laser tracker to perform high-speed three-dimensional scanning on the tank bottom, and quickly obtains actual point cloud data of the workpiece surface.

[0036] The application provides a rocket tank bottom laser welding method, which constructs a whole-process multi-parameter intelligent monitoring and self-adaptive control system, integrates control of a laser, a cooling system and a protective gas system in a welding / cutting control cabinet group, realizes centralized, accurate and closed-loop control of core process parameters such as laser power, cooling water temperature and gas flow, and provides a rocket tank bottom laser welding system suitable for five specifications of 3350 level to 6500 level tank bottoms.

[0037] In summary, the technical scheme combines four technical means of precise robot / RGV execution, three-dimensional measurement intelligent correction, multi-parameter self-adaptive control and modular flexible production, systematically solves inherent problems of traditional welding methods in consistency, precision, deformation control and efficiency, and forms a high-precision, high-stability and high-efficiency intelligent manufacturing solution for rocket tank bottoms.

[0038] The above is only the preferred embodiment of the application, and does not limit the patent range of the application, and any equivalent structure or equivalent flow transformation using the content of the specification and drawings, or direct or indirect application in other related technical fields, is also included in the patent protection range of the application.

Claims

1. A laser welding system for a rocket tank bottom, comprising: The system comprises: a cutting control panel, a guide rail, a welding control panel, an RGV vehicle, a storage box bottom, a welding robot, and a measuring cutting robot; the guide rail is an RGV guide rail system, comprising a linearly laid guide rail body and an RGV vehicle mounted on the guide rail body; the storage box bottom is fixed on the RGV vehicle; the welding control panel is used for the laser welding robot to interact with an operator, and stores parameter settings and welding process parameter settings input by the operator for the laser welding robot; the welding robot and the measuring cutting robot are respectively arranged on one side of the guide rail; the welding robot and the measuring cutting robot are both 6-axis industrial robots with high rigidity; the welding robot comprises a welding robot body, a first fiber laser, a welding head, a first cooling system, and a first auxiliary gas system; the first fiber laser and the welding head are arranged on a mechanical arm of the welding robot body; the first cooling system is used for directly cooling the welding head; the first auxiliary gas system is used for providing pneumatic driving power for the welding robot body; the welding robot body is used for synchronous movement of the first fiber laser and the welding head, and performs welding operation of a girth seam and a longitudinal seam on the storage box bottom; the measuring cutting robot comprises a measuring cutting robot body, a second fiber laser, a cutting head, a second cooling system, and a second auxiliary gas system; the second fiber laser and the cutting head are arranged on a mechanical arm of the measuring cutting robot body; the second cooling system is used for directly cooling the cutting head; the second auxiliary gas system is used for providing pneumatic driving power for the measuring cutting robot body; the measuring cutting robot body is used for synchronous movement of the second fiber laser and the cutting head, and performs operation of measuring X, Y, and Z positioning coordinate data of the storage box bottom and controlling a cutting allowance of the cutting head on the girth seam and the longitudinal seam of the storage box bottom.

2. The system of claim 1, wherein, The system further comprises a nitrogen gas tank and a pressure stabilizing tank; the nitrogen gas tank is a container for storing nitrogen gas; the pressure stabilizing tank is used for pressure stabilization operation of nitrogen gas in the nitrogen gas tank; one end of the pressure stabilizing tank is communicated with the nitrogen gas tank, and the other end of the pressure stabilizing tank is respectively communicated with the first auxiliary gas system and the second auxiliary gas system.

3. The system of claim 1, wherein, The system further comprises a welding control cabinet group and a laser welding control cabinet group; the welding control cabinet group is used for receiving control instructions input by an operator, and performs control operation on the welding robot according to the control instructions; the laser welding control cabinet group is used for controlling the first fiber laser, the welding head, the first cooling system, and the first auxiliary gas system of the welding robot.

4. The system of claim 1, wherein, The system further comprises a welding cooling cabinet group; the welding cooling cabinet group is used for performing cooling operation on the welding head.

5. The system of claim 1, wherein, The system further comprises a cutting control cabinet group and a laser cutting control cabinet group; the cutting control cabinet group is used for receiving control instructions input by an operator and performing control operations on the measuring and cutting robot according to the control instructions; and the laser cutting control cabinet group is used for controlling the second fiber laser, the cutting head, the second cooling system and the second auxiliary gas system of the measuring and cutting robot.

6. The system of claim 5, wherein, The system further comprises a cutting cooling cabinet group; the cutting cooling cabinet group is used for performing cooling operations on the cutting head through a circulating water cooling system.

7. The system of claim 6, wherein, The cutting cooling cabinet group is used for collecting the temperature of the current cutting head in real time when performing the cooling operation on the current cutting head, and performing overheat cooling processing operations on the welding head through the PID temperature closed-loop control circulating water cooling system if the current temperature exceeds the preset high warning temperature.

8. The system of claim 5, wherein, The system further comprises an RGV vehicle remote controller; the RGV vehicle remote controller is used for controlling the RGV vehicle to perform speed control, forward control, backward control, and ascending control, descending control, rotating control, starting control, stopping control and resetting control operations.

9. The system of claim 8, wherein, The system further comprises a hydraulic and pneumatic system and a shielding gas control cabinet group; the hydraulic and pneumatic system is used for circulating air to control pneumatic valves; the hydraulic and pneumatic system comprises a gas cylinder, pneumatic valves, a flow sensor, pneumatic control devices and pipelines; and the shielding gas control cabinet group is used for controlling the pneumatic control devices.

10. A method of laser welding a rocket tank bottom, characterized in that The system performs welding control operations by using the rocket tank bottom laser welding system according to any one of claims 1-9, and comprises the following operation steps: Step S1: the system first performs a self-checking program to check whether there is an alarm information of the welding robot, the measuring and cutting robot, the hydraulic and pneumatic system and the shielding gas control cabinet group, and checks whether the welded workpiece is in place, and prepares for the next step; Step S2: the current program is controlled to enter the second fiber laser of the measuring and cutting robot body to perform 3D scanning on the tank bottom to obtain a laser point cloud image of the tank bottom, compare the laser point cloud image with a preset point cloud image model, determine whether the similarity of the laser point cloud image of the current tank bottom exceeds a first standard threshold, if yes, it is determined to be qualified, if no, it is determined to be unqualified, and the cutting head is controlled to start laser cutting operation to remove the excess until the next step is performed; the measuring and cutting robot body, the second fiber laser, the cutting head, the second cooling system and the second auxiliary gas system; the second fiber laser and the cutting head are arranged on the mechanical arm of the measuring and cutting robot body; the second cooling system is used for directly cooling the cutting head Step S3: the current program is controlled to enter the welding robot, and first controls the welding head of the welding robot to perform longitudinal seam welding operation on the current tank bottom, and after the longitudinal seam welding is completed, the next step is prepared; Step S4: the current program is controlled to enter the measuring and cutting robot, and first controls the second fiber laser of the measuring and cutting robot to perform 3D scanning on the current tank bottom to obtain a laser point cloud image of the tank bottom, and then controls the second fiber laser to perform laser cutting operation on the current tank bottom to remove the excess until the next step is performed. Step S4, control the current program to enter the second fiber laser of the cutting robot body, re-perform the 3D scanning of the tank bottom to obtain the laser point cloud image of the tank bottom, compare the laser point cloud image with the standard longitudinal seam of the preset point cloud image model, judge whether the similarity of the longitudinal seam of the laser point cloud image of the current tank bottom exceeds the second standard threshold, if it is determined to be qualified, if it is not, it is determined to be unqualified, and control the cutting head to start laser cutting operation to remove the excess until the next step is qualified; Step S5, control the current program to enter the welding robot, control the welding head of the welding robot to perform the girth seam welding operation on the current tank bottom, and after the girth seam welding is completed, prepare for the next step; Step S6, control the current program to enter the second fiber laser of the cutting robot body, re-perform the 3D scanning of the tank bottom to obtain the laser point cloud image of the tank bottom, compare the laser point cloud image with the standard girth seam of the preset point cloud image model, judge whether the similarity of the girth seam of the laser point cloud image of the current tank bottom exceeds the third standard threshold, if it is determined to be qualified, if it is not, it is determined to be unqualified, and control the cutting head to start laser cutting operation to remove the excess until the next step is qualified; Step S7, control the program to end.

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