Large-diameter double-sealing flange structure and assembling method and device

Abstract

The invention discloses a large-diameter double-sealing flange structure and an assembling method and device. The large-diameter double-sealing flange structure comprises an AGV mounting vehicle serving as a moving platform; the visual positioning system and the robot system are arranged on the AGV mounting vehicle; the visual positioning system is used for positioning a rocket body flange and comprises a 2D camera used for primary coarse positioning and a three-coordinate detection head used for secondary fine positioning. The special clamp is used for clamping the multi-way pressure accumulator and is installed at the tail end of the robot system. The multi-degree-of-freedom adjusting and mounting method and device are provided when the ultra-large-mass eight-way pressure accumulator is mounted, and the problems that in the mounting process of a double-sealing flange structure, ring cutting and leakage are likely to happen are solved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of aerospace technology, and particularly relates to a large-diameter double-channel sealing flange structure and an assembling method and device. BACKGROUND

[0002] In a space launch vehicle, a pressure accumulator is an important device for ensuring the stability and success of the rocket launching process, for storing hydraulic energy, buffering impact pressure, adjusting fluid pressure, and achieving POGO vibration suppression and ensuring hydraulic system stability. The mechanism needs to maintain normal operation during the entire flight process, and in order to ensure that the diaphragm box does not exceed the limit under the maximum pressure at the pump inlet, high-precision assembly is required to achieve a rigid connection with high airtightness between the pressure accumulator and the engine and the pipeline system.

[0003] The sealing structure is the key of the pressurized delivery system. The single-channel flange sealing structure is used for the docking flange of the pressure accumulator and the engine of the active rocket. The flange has a diameter of about 200mm to 300mm, and the sealing ring often uses a metal butterfly sealing element. During the flange docking process, elastic deformation of the metal butterfly sealing ring occurs through extrusion, thereby achieving sealing of the pressurized delivery system.

[0004] Then, for the new large launch vehicle using a multi-engine parallel structure, the fuel delivery demand is greatly increased. The docking flange diameter of the pressure accumulator and the tank reaches 600mm to 800mm. With the increase of the flange diameter, it is found through ground process tests that the single-channel sealing structure is prone to leakage due to large flange deformation, and cannot meet the fuel supply demand of the pressurized delivery system. SUMMARY

[0005] Therefore, the present application aims to provide a large-diameter double-channel sealing flange structure and an assembling method and device to solve at least one technical problem in the background art. For the installation of an ultra-large mass eight-way pressure accumulator, a multi-degree-of-freedom adjustment installation method and device are proposed to solve the problems of cutting and leakage during the installation process of the double-channel sealing flange structure, To achieve the above-mentioned purpose, the technical scheme of the present application is as follows: An assembling device of a large-diameter double-channel sealing flange structure, comprising: an AGV installation vehicle as a mobile platform; a visual positioning system and a robot system arranged on the AGV installation vehicle; the visual positioning system is used for positioning the rocket body flange, which comprises a 2D camera for rough positioning and a three-coordinate probe head for fine positioning; a special fixture is used for clamping a multi-way pressure accumulator and is installed at the end of the robot system.

[0006] Further, the special fixture is a C-shaped fixture, and both ends thereof are provided with connecting flanges for connecting with two symmetrical flange openings on the multi-way pressure accumulator.

[0007] Further, the end of the robot system is provided with a pneumatic chuck connecting plate, and a pneumatic chuck and a plurality of guide columns are installed on the pneumatic chuck connecting plate. The top of the special fixture is provided with a positioning plate, the positioning plate is provided with a guide hole matched with the guide column, and a pull pin for clamping the pneumatic chuck.

[0008] Further, the 2D camera and the three-coordinate probe head of the visual positioning device are arranged on the workbench.

[0009] An assembly method of a large-diameter double-seal flange structure, using the assembly device of the large-diameter double-seal flange structure, comprising the following steps: S1: driving the AGV mounting vehicle to the mounting station and performing hydraulic support fixation; S2: using a 2D camera to preliminarily position the arrow body flange, obtaining the X, Y coordinates and angle of the flange center, and using a three-coordinate probe head to contact the flange plane and the inner diameter to obtain the accurate spatial coordinates and attitude of the flange; S3: the flexible multi-degree-of-freedom attitude adjustment mechanism grasps the accumulator with the installed C-shaped clamp through the pneumatic chuck, and transports the accumulator to a safe position near the to-be-mounted arrow body flange; S4: the robot system automatically aligns and attaches the accumulator flange to the arrow body flange according to the positioning data obtained by the visual system in step S2; S5: after manual tightening of the bolts, the robot is detached from the clamp and is reset.

[0010] Further, the positioning accuracy of the 2D camera in step S2 for preliminarily positioning the arrow body flange is ≤0.5mm; In step S2, the three-coordinate probe head obtains the accurate center position by touching the inner diameter of the flange for four-point centering, and performs dot measurement on the outer diameter and the plane of the flange to ensure that the parallelism of the butt joint is ≤0.1mm; In step S4, the robot system slowly approaches the arrow body flange at a speed of ≤30mm / s, and monitors the flange contact force in real time through the built-in pressure sensor, sets a contact force threshold for early warning and emergency stop.

[0011] A large-diameter double-seal flange structure, and is applied to the butt joint sealing of a multi-way accumulator and an arrow body flange, a convex flange and a concave flange; A double-seal ring is arranged between the convex flange and the concave flange, which includes a metal butterfly-shaped sealing ring located in the inner ring and a metal O-shaped sealing ring located in the outer ring; A leak detection opening is arranged on the convex flange or the concave flange; The leak detection opening is in communication with the annular area between the metal butterfly-shaped sealing ring and the metal O-shaped sealing ring.

[0012] Further, the abutting surfaces of the convex flange and the concave flange are respectively machined with sealing grooves precisely matched with the metal butterfly sealing ring and the metal O-shaped ring; One end of the leak detection port leads to a circumferential closed cavity separated by two sealing rings, and the other end leads to the outside of the flange; The flange diameter of the large-diameter double-seal flange structure is greater than 500 mm.

[0013] Further, the steps include: Test the inner channel sealing: fill the first helium mixture into the system to be tested, detect the sealing performance of the inner metal butterfly sealing ring through the leak detection port, and detect the combined leakage rate of the double sealing ring through the gap between the abutting flanges; Test the outer channel sealing: fill the second helium mixture into the circumferential area through the leak detection port, detect the sealing performance of the outer metal O-shaped sealing ring through the gap between the abutting flanges, and detect the sealing performance of the inner metal butterfly sealing ring through the accumulator delivery port. Both the inner channel sealing test and the outer channel sealing test are qualified, ensuring that the flight working condition requirements are met.

[0014] Further, the first helium mixture in the inner channel sealing test is low-concentration helium, and the helium volume content is 5%; the second helium mixture in the outer channel sealing test is high-concentration helium, and the helium volume content is 100%; Before the inner channel sealing test and the outer channel sealing test, the leak detection system sensitivity is also included: Measure the background noise value I of the leak detector n and the background value I o ; Use the standard leak hole to obtain its standard leakage rate value Q o and its stable signal value I on the leak detector; According to formula (1), calculate the effective minimum detectable leakage rate Q min , and require that Q min is not greater than 1×10 -10 Pa·m³ / s; (1); Both the inner channel sealing test and the outer channel sealing test use the comparison measurement method for leakage rate quantification, which includes: Place the positive pressure standard leak hole with known leakage rate Q o in the comparison device, accumulate for a predetermined time, and then use the leak detector suction gun to detect and obtain the output value I1. The background output value in the factory building is I0. Calculate the net output value through formula (2); (2); Detect the measured part, the detection time is 60 seconds, obtain the output value I2, and the background output value in the factory building is I0. Calculate the net output value ΔI2; (3); The leakage rate Q of the measured site is calculated according to formula (4): (4); When the net output value ΔI2 (i.e. I2-I0) of the measured point is 0, it is determined that the leakage rate of the measured part is less than the minimum detectable leakage rate. When measuring the leakage rate at different locations on a flange, the maximum value among all measurement locations on the flange is recorded as the final leakage rate value for that test.

[0015] Compared with the prior art, the large-diameter double-sealed flange structure, assembly method, and device described in this invention have the following advantages: 1. This application provides redundancy for the dual-seal design, and the intermediate leak detection chamber enables independent online monitoring of each seal, fundamentally solving the leakage problem of large-diameter flanges.

[0016] 2. This application combines vision and robotics to improve assembly accuracy from millimeter level, which relies on human experience, to a stable and reliable 0.05mm level, completely eliminating the "cutting" or misalignment of the sealing ring caused by misalignment.

[0017] 3. The solution using AGVs and robots in this application frees operators from heavy physical labor and dangerous operations in confined spaces, allowing their main role to shift to supervision, preparation, and emergency response, thereby improving safety and production efficiency.

[0018] 4. The positioning and force control data of the entire process can be recorded and archived, providing data support for the assembly quality of each rocket and realizing the digitalization and traceability of the process. Attached Figure Description

[0019] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of a large-diameter double-sealed flange structure proposed in this invention; Figure 2 This is a schematic diagram of an assembly device for a large-diameter double-seal flange structure proposed in this invention. Figure 3 This is a schematic diagram of an assembly method for a large-diameter double-seal flange structure proposed in this invention. Figure 4 This is a schematic diagram of a multi-port accumulator connection based on a large-diameter double-sealed flange structure proposed in this invention; Figure 5 This is a schematic diagram of the installation and connection of a multi-port accumulator with a large-diameter double-sealed flange structure proposed in this invention; Figure 6 This is a schematic diagram of the vision system control principle for a large-diameter double-sealed flange structure proposed in this invention. Figure 7 This is a visually guided coarse positioning diagram of a large-diameter double-sealed flange structure proposed in this invention; Figure 8 This is a schematic diagram of the secondary precise positioning of a three-coordinate probe for a large-diameter double-sealed flange structure proposed in this invention.

[0020] Explanation of reference numerals in the attached figures: 1. Convex flange; 2. Leak detection port; 3. Metal O-ring seal; 4. Metal butterfly seal; 5. Concave flange; 6. AGV installation vehicle; 7. Vision positioning system; 8. Clamping multi-port accumulator; 9. Robot system; 10. Pneumatic chuck connecting plate; 11. Special fixture; 12. Multi-port accumulator; 13. Connecting flange; 14. Guide column; 15. Pneumatic chuck; 16. Tie nail; 17. Positioning plate Detailed Implementation

[0021] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0022] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] Example 1 Traditional single-seal systems fail when the diameter exceeds 500mm because the flange rigidity decreases and warping deformation occurs, leading to uneven pressure on the sealing line.

[0026] This application employs a dual-seal design. The inner seal uses a metal butterfly seal ring. The inner seal has spring-like elasticity, providing a certain degree of resilience even after the bolt preload is released, accommodating certain flange separations. As the main seal, the inner seal bears the primary pressure within the system.

[0027] The outer seal uses a metal O-ring. It has strong plastic deformation capacity and good filling performance, effectively compensating for macroscopic unevenness of the flange surface. As a secondary seal, it, together with the inner seal, forms a sealed circumferential leak detection chamber.

[0028] A dedicated leak detection port is machined on the delivery flange, which connects to the annular cavity between the inner and outer sealing rings. The dimensional tolerances and surface roughness of the sealing groove must be precision-machined according to the national standards (such as GJB) of the selected metal sealing rings to ensure proper positioning and the designed compression deformation of the sealing rings. This system is a high-end assembly unit that integrates transportation, positioning, grasping, vision, and force control.

[0029] AGV mobile platforms carry robots and accumulators, enabling flexible transfer between workstations.

[0030] Equipped with four hydraulic support legs at the corners, the entire platform can be rigidly supported on the ground when extended, with a single leg support force of >1500kg, completely eliminating the swaying caused by the robot's movement.

[0031] The robot posture adjustment system utilizes high-load (≥300kg), multi-degree-of-freedom (typically 6 axes or more) industrial robots. Force control sensors are integrated into the robot's end effector or joints to monitor contact forces in real time during the docking process. High repeatability ensures the robot can accurately reproduce the position calculated by the vision system.

[0032] A dedicated clamping system (C-type clamp), constructed of Q355B steel, is C-shaped and bridging the accumulator body. It is fixed to the flange openings of quadrants I and III of the accumulator via two connecting flanges, utilizing the existing structure and eliminating the need for additional tooling interfaces. Connection with a robot: A pneumatic chuck is installed at the end of the robot as an active connection mechanism.

[0033] The positioning plate and pull studs are installed on the top of the C-shaped fixture, and the main connection is achieved by the pull studs engaging with the pneumatic chuck. The four guide posts at the end of the robot are first inserted into the guide holes of the fixture to achieve coarse positioning and anti-torsion, guiding the pneumatic chuck to precisely engage with the pull studs.

[0034] The visual positioning system uses a 2D camera to quickly acquire two-dimensional images of the flange and identify the center and angle.

[0035] The coordinate measuring machine (CMM) probe is a high-precision contact probe used to acquire accurate three-dimensional coordinate information.

[0036] One-time localization (2D camera): Using template matching or deep learning target detection algorithms, the flange outline is identified from the image and its center pixel coordinates are calculated. The coordinates are then converted into X, Y, A (angle) coordinates in the robot coordinate system through camera calibration.

[0037] Secondary positioning (three-coordinate probe): Z-axis positioning: Control the probe to contact multiple points on the flange end face, fit a precise plane, and obtain the Z-axis coordinates and flatness. X / Y-axis positioning: Control the probe to extend into the flange inner hole, contact the inner wall using the "four-point centering method", and accurately calculate the center coordinates of the flange hole.

[0038] Dot measurements are taken on the outer diameter and end face edge of the flange to verify the attitude deviation between the flange axis and the robot end, ensuring that the axis is parallel during docking.

[0039] Step 1: System positioning and stabilization; The operator remotely controls the AGV to enter the narrow installation area beneath the arrow body. The AGV automatically or manually activates the four corner hydraulic supports to lift and lock the vehicle body. The AGV drive power is then turned off to prevent accidental operation.

[0040] Step 2: Robot system initialization; Connect the external power supply to the robot control cabinet. Start the robot system and confirm via the teach pendant that there are no alarms on any axis. The system then enters standby mode.

[0041] Step 3: Vision system calibration and flange reference establishment; The robot moves to the tool rack and grabs the integrated module of "2D camera + three coordinate probe".

[0042] First coarse positioning: The robot moves to a position where the camera can see the flange of the rocket body, takes an image, the vision system calculates and guides the robot to move to the vicinity of the center axis of the flange, and then moves back to a safe distance.

[0043] Secondary precision positioning: The robot-controlled coordinate measuring machine (CMM) probe contacts the flange end face (at least 3 points) and records the Z-axis coordinates. The robot-controlled probe enters the flange inner hole, contacting the inner wall at 0°, 90°, 180°, and 270°, recording the coordinates of each point, and accurately calculating the X / Y coordinates of the center. Additional points are marked on the flange outer diameter and end face edge to calculate perpendicularity. The calculated final flange center coordinates, plane normal vector, and other data are stored as the "reference coordinate system" for this assembly.

[0044] Step 4: Accumulator grabbing and pre-alignment; The operator prepares the C-clamp to install the accumulator and installs four Φ14mm guide pins on the rocket body flange.

[0045] The robot moves to the accumulator parking position, the end guide post is inserted into the clamp guide hole, the pneumatic chuck moves, clamps the pull pin, and completes the gripping.

[0046] For initial alignment, the robot, carrying the accumulator, carefully inserts its flange outer diameter (Φ660mm) into the inside of the four locating pins of the arrow body flange, but does not contact the flange surface.

[0047] Manual verification: The operator uses a feeler gauge to measure the gap between the accumulator flange and each locating pin. The robot then makes fine adjustments to ensure that the gaps are uniform around the perimeter, proving that the alignment is good. After completion, the robot carries the accumulator back to a safe position.

[0048] Install the sealing rings: The operator manually installs the metal butterfly rings and metal O-rings into the corresponding sealing grooves of the accumulator flange, and checks to confirm that there is no twisting or damage.

[0049] Step 5: Precise alignment and fitting; The robot removes the vision module and switches back to gripping mode. At a low speed (≤30mm / s), the robot slowly approaches the rocket body flange along the flange's central axis. Force control monitoring: The robot's built-in force sensors monitor six-dimensional force / torque in real time. Safety thresholds are set: Contact force > 50N: The system alarms, alerting the operator. Contact force > 100N: The system immediately stops to prevent damage to the seals or the product. With the dual protection of vision and force control, the robot ultimately fits the accumulator flange to the rocket body flange.

[0050] Flatness is guaranteed to be ≤0.1mm through previous visual measurements.

[0051] The compression of the sealing ring is controlled by the precise displacement of the robot to ensure that the compression rate is within the designed range of 30%-50%.

[0052] Step Six: Tighten and Reset the System; The operator manually tightens the bolts and installs the loose flange. All M14 high-strength bolts are manually inserted.

[0053] Using a torque wrench or hydraulic wrench, tighten all bolts symmetrically and crosswise according to the process requirements, following the sequence and torque of initial tightening (e.g., 30% torque), secondary tightening (e.g., 70% torque), and final tightening (100% torque).

[0054] Robot Retreat: After confirming that the clamping is secure, the operator manually disconnects the C-clamp from the accumulator flange. The robot, carrying the C-clamp, retreats to a safe position, returns the clamp to the tool rack, and releases the pneumatic chuck. The robot returns to its initial zero position and the power is cut off.

[0055] Step 7: Site cleanup and AGV withdrawal; The operator retracts the four hydraulic support legs of the AGV. The AGV is then started and remotely or automatically navigated to the designated parking area. The site is cleaned up, and the assembly process is complete.

[0056] Example 2 This application addresses the development of a new ultra-large diameter eight-way accumulator (diameter > 1m, weight > 100kg, flange diameter > 600mm). To ensure that the pressurization and delivery system meets the rocket flight requirements after accumulator installation, a large-diameter double-flange sealing structure is designed. The sealing rings adopt a combination of metal butterfly seals and metal O-rings; the metal butterfly seal is located on the inner ring, and the metal O-ring is located on the outer ring; the leak detection port is located on the delivery flange and communicates with the circumferential area between the two sealing structures. See Figure X for details.

[0057] Based on the sealing structure and flight operating conditions, the design requires a leakage rate of ≤10%. -5 Pa·m 3 At / s, the soap bubble method can no longer meet the leak detection requirements. Since the vacuum pressure change method cannot be used in the general assembly environment, helium mass spectrometry positive pressure leak detection is usually used. The leak detection plan is as follows: (1) Fill the oxygen supply system with helium mixture, and test the inner ring sealing performance through the leak detection port and test the combined leakage rate of the double seals through the gap of the docking flange. (2) Fill the circumferential connection area between the inner and outer sealing ring structures with helium mixture through the leak detection port, and test the metal O-ring sealing performance through the gap of the docking flange; test the sealing performance of the inner butterfly sealing ring through the accumulator delivery port.

[0058] The helium mass spectrometry positive pressure leak detection procedure for the dual-seal structure of the accumulator docking flange is as follows: Step 1: Fill the system under test with a helium mixture: For oxygen systems with a large storage tank, use low-concentration helium with a He volume content of 5% for leak detection; for the circumferential area connecting the inner and outer sealing structures with a small volume, use high-concentration helium with a He volume content of 100% for leak detection.

[0059] Step 2: Measure the effective minimum detectable leak rate: Record the background noise value I displayed on the output of the leak detector. n Background value I o Standard leakage value Q o And the stable signal value I of the standard leak, requiring that the minimum detectable leak rate before and after leak detection should not exceed 1×10 -10 Effective minimum detectable leak rate Q min It can be calculated using the following formula: (1) Step 3: Measure the leak rate of the comparison device: A positive pressure standard leak with a known leak rate is placed in the comparison device, and the accumulation time is the same as that of the inspected part. After the accumulation time is completed, the suction gun is inserted into the comparison device for detection. The leak detector outputs the output value I1 corresponding to the leak rate of the standard leak. The net output value of the standard leak on the leak detector is as follows: (2) Step 4: Measure the leak rate of the system under test.

[0060] The test area is inspected for 60 seconds. During this time, the leak detector displays the output value I2 of the test point, and the background output value inside the factory is I0. The net output value of the test point can then be obtained. (3) Step 5: Helium detection data conversion.

[0061] The leak rate at the detection point is calculated based on the helium mass spectrometry leak detection conversion formula: (4) When the net output of the measured point When the value is 0, the leak rate of the tested part is considered to be less than the detectable leak rate. In actual helium leak detection, when measuring the leak rate at different locations on the flange, the value usually fluctuates. The maximum value of the same flange is actually recorded, and the fluctuation of the helium leak detection rate caused by the gap value deviation is usually not considered.

[0062] Both leak detection methods passed the leak test, ensuring that the requirements for flight conditions are met.

[0063] For a new type of ultra-large mass multi-port accumulator, an automated docking and assembly process based on a vision system was proposed, and an automated docking device based on a vision system was developed. This equipment includes an AGV installation vehicle, a flexible multi-degree-of-freedom attitude adjustment mechanism, a vision positioning device, and an end effector that clamps the accumulator via a robotic arm. The process is safe and reliable. It can extend the clamping arm of the accumulator to the recessed area at the bottom of the housing, meeting the installation requirements of limited space.

[0064] Special clamp for gripping and docking of pressure device Based on on-site accumulator installation experience, flange openings in quadrants I and III are selected as the mounting ports for the C-type clamps. Figure 5 As shown. This C-clamp consists of two connecting flanges, a C-clamp body, a positioning plate, and corresponding connecting fasteners. The main body is made of Q355B material. In use, first fix the two connecting flanges to the accumulator quadrants I and III flanges, then fix the C-clamp to the two connecting flanges. The C-clamp is connected to the robot using a pneumatic chuck connection. A positioning plate can be installed on the top connecting end of the C-clamp. The positioning plate has two pull studs and four guide holes. The top of the robot is equipped with a pneumatic chuck connecting plate and a pneumatic chuck. The pneumatic chuck connecting plate has four guide posts. The robot connects to the C-clamp by inserting the four guide posts on the pneumatic chuck connecting plate into the guide holes on the top positioning plate of the C-clamp, and the pneumatic chuck engages with the pull studs. Figure 4 As shown.

[0065] visual system (1) Working principle: First, the center and end face of the flange are initially determined by a single 2D camera. Then, a three-coordinate probe is used for secondary positioning to accurately determine the center and end face of the flange. Finally, the flange information obtained by the vision system is transmitted to the robot control system in real time.

[0066] (2) Hardware equipment: A single 2D camera is used to perform initial positioning: the center and end face of the flange are initially determined. (3) Measurement algorithm: The 2D camera is responsible for acquiring the X, Y and angle positioning of the plane. By analyzing the distance and pose information in the depth direction fed back by the three-coordinate probe, the coordinate information of the measured object with depth is obtained, thus achieving accurate positioning in the horizontal direction.

[0067] The basic principle of 2D monocular vision is to obtain the X and Y coordinates of a flange surface using real-time acquired image data. The first method is template matching based on image processing algorithms. The second method is image recognition technology based on deep learning. It is worth noting that a single image is insufficient to accurately obtain the distance information of the object being measured.

[0068] The basic principle of a coordinate measuring machine (CMM) probe is as follows: First, by coordinating the movement of the sensor (probe) with the axis of the measurement space, the discrete spatial positions of the elements of the measured set are obtained. Then, through mathematical formulas, the measured point cloud is analyzed and fitted. Finally, the measured geometric elements are reconstructed, and the deviation between these deviations and the theoretical values ​​is calculated, thereby completing the inspection of the measured part.

[0069] Operating procedures Step 1: AGV positioning and parking; 1) Navigation mode selection, mode (manual remote control): The operator drives the vehicle to the accumulator installation position through the AGV remote controller.

[0070] 2) Parking and securing: After the AGV arrives at the workstation, activate the four-corner hydraulic support units to ensure the vehicle body is stable (single leg support force > 1500kg).

[0071] Turn off the AGV power supply to avoid movement interfering with subsequent robot operations.

[0072] Step 2: Start the robot system; 1) Power connection: Connect the robot control cabinet to the power supply via the wired connector (voltage 200-600V, power consumption 2.8kW). Confirm that the connector is securely plugged in and out without any looseness.

[0073] 2) Powering on the robot: Start the robot control cabinet and enter standby mode. Use the teach pendant to activate the robot body and check whether the movement of each axis is normal.

[0074] Step 3: Visual positioning system calibration; 1) Camera and probe grasping: The robot is controlled by a teach pendant to grasp the integrated module of 2D camera and three-coordinate probe.

[0075] 2) Visual-guided coarse positioning (2D camera) Figure 7 ) The mobile robot moves to the vicinity of the accumulator installation location on the rocket body and activates its camera to capture images of the flange. The center coordinates of the flange are calculated using a visual algorithm, with a positioning accuracy of ≤0.5mm. After center positioning via vision, the robot retreats along the flange's central axis to a safe distance.

[0076] Secondary precise positioning (three-coordinate probe) Figure 8The 2D camera and the coordinate measuring machine (CMM) module are positioned at a fixed distance. Using vision-guided coarse positioning, the robot, carrying a probe, contacts the flange plane to collect Z-axis data. The CMM then retracts along the Z-axis, inserting the probe deep into the inner circle of the accumulator flange. By contacting the inner diameter, X / Y data is acquired using a four-point centering method to obtain the precise flange center position. The outer diameter of the flange is then marked with CMM markers to ensure the robot's spatial perpendicularity. Finally, the flange plane of the rocket body is marked with CMM markers in all directions to ensure a parallelism of 0.1mm during docking.

[0077] Using the 2D camera coordinate system, calculate the flange plane position and flange center deviation (final accuracy ≤ 0.05mm), as well as the safe X / Y / Z positions before installation. Place the 2D camera + coordinate measuring machine lens detection module in its original position.

[0078] Data storage: The positioning coordinate values ​​are stored in the robot control system as a docking reference.

[0079] Step 4: Accumulator pre-installation preparation; 1) C-type gripper gripping: The C-type gripper and accumulator are pre-installed manually. The air source is connected to the robot, and the robot switches to accumulator gripping mode, gripping the C-type gripper through a pneumatic chuck.

[0080] 2) Flange pre-alignment; Manually pre-install locating pins on the top, bottom, left, and right sides of the rocket body flange. The robot pushes the accumulator flange to a safe distance from the rocket body flange, so that the outer diameter (Φ660) of the accumulator flange is inserted into the inside of the four guide locating pins on the rocket body flange but does not contact the rocket body flange. (4 Φ14mm locating pins).

[0081] Manual verification: After the accumulator flange extends to the inside of the four locating pins, use a feeler gauge to measure the gap between the outer diameter of the accumulator flange and the inside of the locating pins. Confirm that the gap between the outer diameter of the accumulator flange and the locating pins is uniform. If there is a deviation, the parameters can be adjusted manually. Return the accumulator to the safe position and remove the guide locating pins on the rocket body flange.

[0082] 3) Installation of sealing rings; The sealing ring is manually installed in the sealing groove of the accumulator flange, and the sealing ring is checked to ensure that it is not twisted or damaged.

[0083] Step 5: Precise positioning and assembly of the accumulator; 1) Low-speed approach (safety mode): The robot slowly approaches the rocket flange at ≤10% of its rated speed (≤30mm / s under a 300kg load). Human supervision is conducted throughout the process to ensure no interference along the path.

[0084] 2) Contact force monitoring: The robot's built-in pressure sensor is activated to monitor the flange contact force in real time (threshold: ≤50N warning, ≥100N emergency stop).

[0085] 3) Final fit, flange flatness error ≤ 0.1mm. Sealing ring compression rate 30%~50%.

[0086] Step Six: Tightening bolts and finishing touches; 1) Bolt insertion and tightening: Manually install the accumulator loose flange. Manually insert M14 high-strength bolts. Tighten in stages (e.g., initial tightening → secondary tightening → final tightening) to ensure even force distribution.

[0087] 2) Disconnection and Reset: Manually disconnect the C-clamp from the accumulator. The robot, with the C-clamp in hand, returns to a safe position. The robot places the C-clamp at the workstation and releases it. The robot returns to its origin. Disconnect the robot's power supply.

[0088] Step 7: AGV transfer and parking; 1) AGV unlocking: Retract the four corner support units to release the AGV from its fixed state.

[0089] 2) Return to parking area: Transfer the AGV to the fixed parking position in the workshop via remote control or automatic navigation to complete the operation cycle.

[0090] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An assembly apparatus for large diameter double-seal flange structures, characterized by: The application relates to a large-diameter double-channel sealing flange structure. The AGV installation vehicle is used as a mobile platform; A visual positioning system and a robot system are arranged on the AGV installation vehicle; The visual positioning system is used for positioning a missile body flange, and comprises a 2D camera for rough positioning and a three-coordinate probe head for fine positioning; A special fixture is used for clamping a multi-channel accumulator and is arranged at the tail end of the robot system.

2. A fitting device for large diameter double-seal flange structure according to claim 1, characterized in that: The special fixture is a C-shaped fixture, two ends of the C-shaped fixture are provided with connecting flanges and are used for being connected with two symmetrical flange openings on the multi-channel accumulator.

3. An assembly device for large diameter double-seal flange structure according to claim 2, characterized in that: The tail end of the robot system is provided with a pneumatic chuck connecting plate, the pneumatic chuck connecting plate is provided with a pneumatic chuck and a plurality of guide columns; The top of the special fixture is provided with a positioning plate, the positioning plate is provided with guide holes matched with the guide columns and is provided with a pull pin for clamping the pneumatic chuck.

4. An assembly device for large diameter double-seal flange structure according to claim 1, characterized in that: The 2D camera and the three-coordinate probe head of the visual positioning device are arranged on a workbench.

5. A method of assembling a large diameter double-seal flange structure using the assembly apparatus of any one of claims 1 to 4, characterized in that: The application further discloses a positioning method. S1: driving the AGV installation vehicle to an installation station and fixing the AGV installation vehicle through hydraulic support; S2: preliminarily positioning the missile body flange through the 2D camera, acquiring X and Y coordinates and an angle of a flange center, contacting a flange plane and an inner diameter through the three-coordinate probe head and acquiring accurate spatial coordinates and an attitude of the flange; S3: a flexible multi-degree-of-freedom attitude adjusting mechanism grasps the accumulator with the installed C-shaped fixture through the pneumatic chuck, and transports the accumulator to a safe position near the missile body flange to be installed; S4: the robot system automatically aligns and attaches the accumulator flange to the missile body flange according to the positioning data acquired by the visual system in step S2; S5: after artificial bolt fastening, the robot is separated from the fixture and is reset.

6. A method of assembling a large diameter double-seal flange construction according to claim 5, characterized in that: The positioning precision of the 2D camera in step S2 is less than or equal to 0.5 mm; The three-coordinate probe head in step S2 contacts the inner diameter of the flange to acquire an accurate center position through four-point centering, and performs dotting measurement on the outer diameter and the plane of the flange to ensure that the parallelism of the butt joint is less than or equal to 0.1 mm; In step S4, the robot system slowly approaches the missile body flange at a speed less than or equal to 30 mm / s, and the built-in pressure sensor is used for monitoring the flange contact force in real time, a contact force threshold is set to perform early warning and emergency stop.

7. A large diameter double seal flange structure, and is applied to the butt sealing of the multi-pass accumulator and the arrow body flange, characterized in that: A convex flange and a concave flange; A double-channel sealing ring is arranged between the convex flange and the concave flange, and the double-channel sealing ring comprises a metal butterfly-shaped sealing ring located in an inner ring and a metal O-shaped sealing ring located in an outer ring; A leak detection opening is arranged on the convex flange or the concave flange; The leak detection opening is connected with a ring-shaped area between the metal butterfly-shaped sealing ring and the metal O-shaped sealing ring.

8. A large diameter double-seal flange construction according to claim 7, characterized in that: Sealing grooves matched with the metal butterfly-shaped sealing ring and the metal O-shaped ring are respectively formed on butt joint surfaces of the convex flange and the concave flange; One end of the leak detection opening leads to a ring-shaped closed cavity separated by the two sealing rings, and the other end leads to the outside of the flange. The flange diameter of the large-diameter double-channel sealing flange structure is greater than 500 mm.

9. The method according to claim 7 or 8, characterized in that: The application further discloses a leak detection method. The inner-channel sealing is tested: the first helium mixed gas is filled into a system to be detected, the sealing performance of the metal butterfly-shaped sealing ring in the inner ring is detected through the leak detection opening, and the combined leakage rate of the double-channel sealing ring is detected through the gap between the butt joint flanges. Test outer seal: the second helium mixture is filled into the annular area through the leak detection port, the sealing performance of the outer metal O-ring is detected through the butt flange gap, and the sealing performance of the inner metal butterfly-shaped seal ring is detected through the accumulator delivery port. Both the test inner seal and the test outer seal are leak detection qualified, which ensures that the flight working condition requirements are met.

10. The method for detecting the sealing performance of a large-diameter double-seal flange structure according to claim 9, characterized in that: The first helium mixture in the test inner seal is low-concentration helium, and the helium volume content ratio is 5%; the second helium mixture in the test outer seal is high-concentration helium, and the helium volume content ratio is 100%. Before the test inner seal and the test outer seal, the leak detection system sensitivity is also included: The background noise value I of the leak detector is measured n and the background value I o ; With the standard leak, its standard leak rate value Q is obtained o and its stable signal value I on the leak detector; The effective minimum detectable leak rate Q is calculated according to formula (1) min and requires Q min not greater than 1 x 10 -10 Pa m3 / s; (1); In the test inner seal and the test outer seal, the comparative measurement method is used for leak rate quantification, which includes: A positive pressure standard leak with a known leak rate Q o is placed in the comparison device, after accumulating for a predetermined time, the output value I1 is obtained by using a leak detector suction gun, the background output value in the factory building is I0, and the net output value is calculated by formula (2); （2）； The detected part is detected, the detection time is 60 seconds, the output value I2 is obtained, the background output value in the factory building is I0, and the net output value ΔI2 is calculated; （3）； The leakage rate Q of the measured site is calculated according to formula (4): (4); When the net output value ΔI2 (i.e. I2-I0) of the measured point is 0, it is determined that the leak rate of the measured part is less than the minimum detectable leak rate; When measuring the leak rate at different positions of the flange, record the maximum value in all measurement positions of the flange as the final leak rate value of this detection.

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