An aircraft frame welding flexible intelligent tool system with deformation prediction function and a control method thereof

Abstract

The application provides an aircraft framework welding flexible intelligent tool system with a deformation prediction function and a control method thereof, and the tool system comprises a ground rail, a connecting tool, a conformal clamp, a clamp supporting mechanism, a steel jump plate and a workbench; the ground rail is used for supporting the connecting tool; the connecting tool can drive a positioning piece to move along three degrees of freedom of XYZ; the conformal clamp clamps a welding area of a workpiece, adapts to different workpiece surfaces through internal conformal pads, and resists welding force and deformation of the welding area; the clamp supporting mechanism is installed below a weld of a plate piece and is used for supporting a conformal clamp of the plate piece; in addition, the application also designs a force monitoring data-welding deformation prediction method based on Gaussian process regression to predict a welding deformation condition of a product, and the application can realize flexible positioning of multiple-configuration aircraft framework parts, clamping of a welding area and welding deformation prediction of the product, and is helpful to improving high-quality and rapid trial production capability of the aircraft framework.

Description

Technical Field

[0001] This invention relates to the field of aircraft manufacturing technology, specifically to a flexible intelligent tooling system for welding aircraft skeletons with deformation prediction function and its control method. Background Technology

[0002] The aviation manufacturing industry is a strategic industry, and the requirements for aircraft manufacturing are gradually increasing, especially in the manufacture of military aircraft. The skeletal structure of a military aircraft, as its supporting framework, is a crucial part of ensuring the stability and reliability of the aircraft under various flight conditions. With the increasing number of high-performance new aircraft development tasks, new challenges and requirements have been placed on the ability to rapidly and efficiently prototype aircraft skeletal structures.

[0003] Traditional aircraft frame manufacturing involves manufacturing each component separately and then connecting them using fasteners. This approach suffers from problems such as insufficient internal space, suboptimal aerodynamic layout, increased structural weight, and complex assembly and production processes. Welding technology, on the other hand, can weld multiple large frame beams into a single structural component, ensuring the integrity and stability of the aircraft frame structure. As a result, its application in aircraft frame manufacturing is becoming increasingly widespread.

[0004] Currently, aircraft frame welding mainly employs rigid tooling in a "one-to-one" assembly mode for positioning and support. However, with the increasing number of new aircraft development tasks, it is necessary to design and manufacture different rigid tooling to adapt to different aircraft frames for strength testing and structural optimization. This results in high aircraft manufacturing costs and long manufacturing cycles. At the same time, welding forces generated during the welding process can cause deformation of parts, affecting subsequent assembly work. Therefore, it is particularly important to design an intelligent tooling system that can achieve flexible positioning of aircraft frame parts, reliable clamping of the welding area, and prediction of post-weld deformation of frame products. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention proposes a flexible intelligent tooling system for aircraft skeleton welding with deformation prediction function and its control method, aiming to achieve flexible positioning of multi-configuration aircraft skeleton parts, clamping of welding areas, and prediction of post-weld deformation of products.

[0006] To achieve the above-mentioned technical objectives, the present invention provides the following technical solution:

[0007] A flexible intelligent tooling system for welding aircraft skeletons with deformation prediction function, specifically comprising:

[0008] Ground rail, connecting fixture, conformal gripper, gripper support structure, steel scaffolding, worktable and flexible fixture control system;

[0009] Two ground rails are provided, symmetrically fixed at both ends of the pit in the Y direction, supporting the connecting fixture and serving as the base for the X-direction motion axis of the connecting fixture;

[0010] There are four connecting fixtures, each of which is installed on a ground rail and drives the internal angle-adjustable positioning component to move along the XYZ three degrees of freedom.

[0011] The conformal clamp includes a stringer clamp and a plate clamp, which are used to clamp the welds between the stringer and the frame, and between the plate and the frame, respectively, to resist the deformation force during the welding process.

[0012] The clamp support structure is provided in four parts and installed below the weld seam of the plate. It includes a scissor structure, a waist-shaped groove and a support platform. The lifting and lowering movement of the support platform is adjusted by the scissor structure to support the conformal clamp of the plate. The waist-shaped groove set on the surface of the base is connected to different positioning holes on the connecting tooling to achieve flexible positioning of the clamp support structure.

[0013] The workbench is placed around the pit, and the steel scaffolding is placed on the workbench along the Y direction of the system to provide workers with stepping space.

[0014] The flexible tooling control system is installed in the pit and is used to issue command signals to control the entire tooling system to complete the flexible positioning of the aircraft frame and the prediction of post-weld deformation.

[0015] Furthermore, the ground track specifically includes:

[0016] The system comprises a ground rail structure, ground rail guide rails, ground rail racks, leveling feet, and ground rail reinforcing ribs. The ground rail structure serves as the base of the flexible intelligent tooling system and is welded to the leveling feet. The leveling feet are placed on the surface of the pit, and the X-axis straightness of the ground rail is leveled by adding shims. Ground rail reinforcing ribs are installed on the feet to improve the overall rigidity of the ground rail. There are two ground rail guide rails, symmetrically located on both sides of the upper surface of the ground rail. The ground rail rack is installed on the ground rail structure using blind bolts. Tooling partitions are also fixed at both ends of the ground rail to seal the front and rear of the ground rail and prevent debris from entering the tooling system.

[0017] Furthermore, each connecting fixture specifically includes:

[0018] X-axis motor, crossbeam, horizontal motion module, lifting motion module, wiring sheet metal, connecting tooling slider and X-axis limit device;

[0019] The crossbeam is the main load-bearing component of the connecting fixture, including a crossbeam rack, a crossbeam guide rail, and crossbeam structural components. A connecting fixture slider and an X-axis motor are mounted on its bottom surface. The X-axis motor's shaft has an X-axis motor end gear at its end. The X-axis motor end gear meshes with the ground rail rack, and the connecting fixture slider meshes with the ground rail guide rail. Through the transmission method of the gear rack and guide rail meshing, the X-axis movement of the connecting fixture is driven. X-axis limiting devices are installed at both ends of the crossbeam in the X-axis direction to prevent X-axis collisions of the connecting fixture.

[0020] Several horizontal motion modules are arranged along the Y-axis. In each horizontal motion module, two bottom sliders are installed on the bottom surface of the module, and two back sliders are installed on the back side of the module. A Y-axis motor is installed on the front of the module, and a Y-axis motor end gear is located at the end of the motor shaft. The Y-axis motor end gear engages with the crossbeam rack, and the bottom sliders and back sliders of the horizontal motion module engage with the crossbeam guide rail. The Y-axis movement of the horizontal motion module is driven by the gear rack and guide rail. Y-axis limiting devices are installed at both ends of the horizontal motion modules in the Y-axis direction to prevent Y-axis collisions between the horizontal motion modules.

[0021] The lifting motion module includes a lifting module, a lifting connector, a three-dimensional force sensor, and an angle-adjustable positioning component. The lifting module is fixedly connected to the horizontal motion module by bolts to drive the angle-adjustable positioning component to move in the Z direction. The lifting connector is fixedly connected to the lifting module and the three-dimensional force sensor by bolts. The three-dimensional force sensor is fixedly connected to the angle-adjustable positioning component by blind bolts to monitor the contact force data between the angle-adjustable positioning component and the frame.

[0022] Furthermore, the conformal gripper specifically includes:

[0023] The stringer clamp and plate clamp both have a common clamp housing, conformal pad, clamp bolts, and clamp reinforcing ribs. The conformal pad is used to adapt to product surfaces with different curvatures and is connected to the clamp housing by clamp bolts. The stringer clamp and plate clamp are used to clamp stringers and plates, respectively. Their upper and lower surfaces are clamped by clamp bolts, and multiple sets of clamp reinforcing ribs are provided on the surfaces. The clamping holes of the clamp bolts are located on the clamp reinforcing ribs to improve the overall rigidity and clamping reliability of the conformal clamp.

[0024] Furthermore, retractable dustproof bellows covers are installed between two adjacent connecting fixtures, between the outermost connecting fixture and the fixture partition, between two adjacent horizontal motion modules, and between the outermost horizontal motion module and the crossbeam. The bellows covers and fixture partitions are used to protect the internal mechanical structure and electrical components of the fixture system and prevent debris from falling into the fixture system.

[0025] Furthermore, the angle-adjustable positioning component specifically includes:

[0026] The R-axis rotary table and the swing structure are described. The lower outer wall of the R-axis rotary table is fixedly connected to a three-dimensional force sensor by blind bolts, and the upper outer wall is fixedly connected to the swing structure by bolts. The outer side of the R-axis rotary table is engraved with rotation scale to quantify the rotation angle. The swing structure is provided with a rotation center hole, a locking hole, and a positioning hole, which can be connected to the frame through the positioning hole using connecting bolts to position the frame. The swing structure is engraved with swing scale to quantify the swing angle. The rotation center hole is located at the top, and the locking hole is located at the bottom.

[0027] Furthermore, the flexible tooling control system includes:

[0028] The system includes an electrical cabinet, an industrial computer, a PLC controller, and a bus coupling module. The PLC controller and the bus coupling module are installed inside the electrical cabinet, which also houses a motor driver and an air switch connected to the bus. The industrial computer is connected to the PLC controller via a network cable, and the PLC controller is connected to the motor driver via a bus. The motor driver is connected to an X-axis motor, a Y-axis motor, and a lifting module.

[0029] This invention also provides a control method for a flexible intelligent tooling system for welding aircraft skeletons with deformation prediction function, as described above, which specifically includes the following steps:

[0030] S1. Input the control program on the industrial control computer and connect it to the PLC controller. Establish the connection relationship between the control program and the X-axis motor, Y-axis motor, lifting module and motor driver through the PLC controller.

[0031] S2. Import the workpiece model into the industrial control computer and automatically generate the coordinate position that the angle-adjustable positioning part needs to move to. The industrial control computer sends instruction signals to the PLC controller. The PLC controller controls the X-axis motor, Y-axis motor and lifting module of the connected tooling to work and control the angle-adjustable positioning part to move to the specified position.

[0032] S3. Hoisting and loading each frame component, positioning the frame component by the angle-adjustable positioning component on the connecting tooling;

[0033] S4. Load each stringer and clamp the stringers together with each frame piece using the stringer clamp, ensuring that the conformal surface of the conformal pad is fully in contact with the outer surface of the workpiece during the clamping process.

[0034] S5. After the stringers and frame are welded and the post-weld heat treatment is completed, load each plate and clamp the plate and frame together using the plate clamp. During the clamping process, ensure that the conformal curved surface of the conformal pad is completely in contact with the outer surface of the workpiece. Adjust the height of the clamp support structure to support the plate clamp.

[0035] S6. After all the plates have been heat-treated after welding, force monitoring data is obtained through a three-dimensional force sensor. The force monitoring data and prior data are fused to establish a Gaussian regression deformation prediction model. The deformation of the product after welding is predicted by the force monitoring data-post-weld deformation prediction method based on Gaussian process regression. The welding quality of the aircraft frame product is evaluated based on the deformation of the product.

[0036] S7. After welding is completed, when the aircraft frame product is removed from the frame, gradually loosen the clamps at the positioning points, and move the tooling system through manual operation mode in the industrial control computer to lift the product out of the frame.

[0037] Furthermore, step S6 specifically includes:

[0038] S61. Obtain n sets of prior data on the contact force between the angle-adjustable positioning parts and the frame parts and the deformation of the parts after welding through welding simulation of skeleton parts.

[0039] S62. Using the contact force between the frame and the positioning components as the input feature and the post-weld deformation as the output feature, the radial basis kernel function is selected as the covariance function. The hyperparameters in the covariance function are estimated using maximum likelihood. The prediction formula for the post-weld deformation of the product is established through the definition of a multivariate Gaussian distribution as follows:

[0040]

[0041] Where y represents the product deformation data after welding in the prior data, and f * Here, μ(X) represents the product deformation data predicted by the Gaussian regression model, and μ(X) represents the mean of the contact force data in the prior data. * ) represents the mean of the force monitoring data after actual welding, and K is the covariance function of all possible combinations of contact forces in the prior sample. * X for force monitoring data * K is the covariance function of all possible combinations of contact force inputs in the prior samples. ** The covariance function for all possible combinations of force monitoring data;

[0042] S63. Solve the post-weld deformation prediction formula based on the prediction model using the conditional Gaussian standard rule:

[0043]

[0044] in, This represents the uncertainty of the predicted deformation value; based on the condition that the post-weld deformation prediction data follows a multivariate Gaussian distribution, with the highest probability at the mean, the post-weld deformation data f of the aircraft frame product is then... * The best estimate is f * =μ(X) * )+K * K-1 (y-μ(X)).

[0045] Furthermore, step S61 specifically includes:

[0046] S611. Create a parametric model of the skeleton part, including the following features: manufacturing errors of the positioning clamping holes and welding areas; among which, the offset of the center of the part positioning hole in the XYZ direction and the offset of the V-groove angle of the welding area are defined as Gaussian distributed random variables with a mean of 0 and a standard deviation according to the process specification, to ensure that the error space covers the actual manufacturing fluctuations.

[0047] S612. Use the Latin hypercube sampling method to generate n sets of process parameters, including welding speed, heat input, and welding area clamping deviation, and perform welding simulation analysis of skeleton parts.

[0048] S613. Extract the post-weld deformation of the parts and the contact support reaction force at the positioning point from n sets of welding simulation data to obtain prior data for predicting the post-weld deformation of the skeleton parts.

[0049] By employing the above technical solution, the present invention has at least the following beneficial effects:

[0050] This invention presents a flexible intelligent tooling system for aircraft frame welding, capable of adapting to different frame configurations and achieving rapid and precise flexible positioning. The stringer and plate holders clamp the welding area, resisting welding deformation forces. After welding, force detection data is acquired through a three-dimensional force sensor, and a post-weld deformation prediction method based on Gaussian process regression enables the tooling system to predict post-weld deformation of the frame product. This invention effectively improves the high-quality and rapid prototyping capabilities of aircraft frames, enhancing the development level of high-performance aircraft. Attached Figure Description

[0051] Figure 1 This is an overall structural view of a flexible intelligent tooling system for welding aircraft skeletons with deformation prediction function proposed in this invention.

[0052] Figure 2 This is a structural view of the ground rail in a flexible intelligent tooling system;

[0053] Figure 3 This is a structural view of the connecting tooling in a flexible intelligent tooling system;

[0054] Figure 4 This is a structural view of the horizontal motion module and the lifting motion module in a flexible intelligent tooling system.

[0055] Figure 5 A structural view of an angle-adjustable positioning component in a flexible intelligent tooling system;

[0056] Figure 6This is a structural view of the conformal gripper in a flexible intelligent tooling system;

[0057] Figure 7 This is a structural view of the gripper support structure in a flexible intelligent tooling system;

[0058] Figure 8 This is a flowchart of the force-post-weld deformation prediction method based on Gaussian process regression proposed in this invention.

[0059] Figure 9 A schematic diagram of frame positioning for controlling the flexible intelligent tooling system during aircraft skeleton welding;

[0060] Figure 10 A schematic diagram of the stringers after welding, used to control the flexible intelligent tooling system for welding the aircraft frame.

[0061] Figure 11 A schematic diagram of the plate after welding, used to control the flexible intelligent tooling system for welding the aircraft frame.

[0062] Reference numerals: 1-Ground rail; 1.1-Ground rail structural component; 1.2-Ground rail guide rail; 1.3-Ground rail rack; 1.4-Leveling foot; 1.5-Ground rail reinforcing rib; 2-Connecting fixture; 2.1-X-direction motor; 2.1.1-X-direction motor end gear; 2.2-Crossbeam; 2.2.1-Crossbeam rack; 2.2.2-Crossbeam guide rail; 2.2.3-Crossbeam structural component; 2.3-Horizontal motion module; 2.3.1-Horizontal motion module rear bottom slider; 2.3.2-Y-direction motor; 2.3.3-Horizontal motion module rear slider; 2.3.4-Y-direction motor end gear; 2.3.5-Y-direction limiting device; 2.3.6 Front of horizontal motion module; 2.3.7 Back of horizontal motion module; 2.3.8 Rear bottom of horizontal motion module; 2.4-Lifting motion module; 2.4.1-Lifting module; 2.4.2- 2.4.3 Lifting connector; 2.4.4 Three-dimensional force sensor; 2.4.5 Angle-adjustable positioning component; 2.4.4.1 R-axis rotary table; 2.4.4.2 Swing structure; 2.4.4.3 Rotation center hole; 2.4.4.4 Locking hole; 2.4.4.5 Positioning hole; 2.5 Wiring sheet metal; 2.6 Connecting tooling slider; 2.7 X-direction limiting device; 3.1 Conformal clamp; 3.1 Stringer 3.2-Plate clamp; 3.3-Clamp housing; 3.4-Conformable pad; 3.5-Clamp bolt; 3.6-Clamp reinforcing rib; 4-Clamp support structure; 4.1-Scissor lift structure; 4.2-Waist groove; 5-Steel plank; 6-Workbench; 7-Stringer; 8-Frame; 9-Plate; 10-Electrical cabinet; 11-Industrial computer; 12-Bellbell cover; 13-Pit; 14-Tooling partition. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of this invention clearer, the following will be described in conjunction with the appendix. Figure 1-11 The present invention will be described in detail below. It should be noted that these specific embodiments are for illustrative purposes only and do not limit the scope of the invention. Furthermore, the technical features described in the various embodiments can be combined with each other as long as they do not conflict with each other.

[0064] In describing this invention, it should be specifically noted that, unless otherwise expressly specified or limited, the reference to "connection" between one component and another indicates either a direct connection or an indirect connection via an intermediate medium. Terms such as "installation" and "fixation" should be broadly understood; for example, they can refer to a fixed connection, a detachable connection, or an integral connection, as well as a mechanical or electrical connection, a direct connection or an indirect connection via an intermediate medium, and even include the internal communication or interaction between the two components. Those skilled in the art will understand the specific meaning of these terms in this invention according to the specific circumstances.

[0065] Furthermore, although the steps in this invention are arranged with reference numerals, this is not intended to limit the order of the steps. Unless the order of the steps is explicitly stated or the execution of a step requires other steps as a basis, the relative order of the steps can be adjusted. It is understood that the term "and / or" as used herein refers to and covers any and all possible combinations of one or more of the associated listed items.

[0066] like Figure 1 As shown, this invention proposes a flexible intelligent tooling system for welding aircraft skeletons with deformation prediction function, which specifically includes:

[0067] 1. Ground rail, 2. Connecting fixture, 3. Conformal clamp, 4. Clamp support structure, 5. Steel scaffold, 6. Workbench, and 7. Flexible fixture control system.

[0068] Two ground rails 1 are provided and are symmetrically fixed at both ends of the pit 13 in the Y direction to support the connecting fixture 2 and serve as the base of the X-axis motion axis of the connecting fixture 2.

[0069] In this embodiment, as Figure 2 As shown, the ground track 1 specifically includes:

[0070] The system comprises a ground rail structural component 1.1, a ground rail guide rail 1.2, a ground rail rack 1.3, a leveling foot 1.4, and a ground rail reinforcing rib 1.5. The ground rail structural component 1.1 serves as the base of the flexible intelligent tooling system and is welded to the leveling foot 1.4. The leveling foot 1.4 is placed on the surface of the pit 13 and is used to level the X-direction straightness of the ground rail 1 by adding shims. The ground rail reinforcing rib 1.5 is installed on it to improve the overall rigidity of the ground rail. There are two ground rail guide rails 1.2, symmetrically located on both sides of the upper surface of the ground rail. The ground rail rack 1.3 is installed on the ground rail structural component 1.1 by blind bolts. Tooling partitions 14 are also fixed at both ends of the ground rail to seal the front and rear of the ground rail 1 and prevent debris from entering the tooling system.

[0071] There are four connecting fixtures 2, each of which is installed on the ground rail 1 and drives the internal angle-adjustable positioning component 2.4.4 to move along the XYZ three degrees of freedom.

[0072] In this embodiment, as Figure 3 As shown, each connecting fixture 2 specifically includes:

[0073] 2.1 X-axis motor, 2.2 crossbeam, 2.3 horizontal motion module, 2.4 lifting motion module, 2.5 wiring sheet metal, 2.6 connecting tooling slider and 2.7 X-axis limit device;

[0074] The crossbeam 2.2 is the main load-bearing component of the connecting fixture 2, including a crossbeam rack 2.2.1, a crossbeam guide rail 2.2.2, and a crossbeam structural component 2.2.3. A connecting fixture slider 2.6 and an X-axis motor 2.1 are mounted on the bottom surface of the crossbeam 2.2. The X-axis motor 2.1 has an X-axis motor end gear 2.1.1 at the end of its shaft. The X-axis motor end gear 2.1.1 engages with the ground rail rack 1.3, and the connecting fixture slider 2.6 engages with the ground rail guide rail 1.2. Through the transmission method of the gear rack and guide rail engagement, the X-axis movement of the connecting fixture 2 is driven. The X-axis limiting device 2.7 is installed at both ends of the crossbeam 2.2 in the X-axis direction to prevent X-axis collisions of the connecting fixture 2.

[0075] In addition, this application also installs retractable dustproof bellows covers 12 between two adjacent connecting fixtures 2, between the outermost connecting fixture 2 and the fixture partition 14, between two adjacent horizontal motion modules 2.3, and between the outermost horizontal motion module 2.3 and the crossbeam 2.2. The bellows covers 12 and the fixture partition 14 are used to protect the internal mechanical structure and electrical components of the fixture system and prevent debris from falling into the fixture system.

[0076] For example Figure 4As shown, in this embodiment, several horizontal motion modules 2.3 are arranged along the Y direction. In each horizontal motion module 2.3, two horizontal motion module rear bottom surface sliders 2.3.1 are installed on the rear bottom surface 2.3.8 of the horizontal motion module, two horizontal motion module rear bottom surface sliders 2.3.3 are installed on the back surface 2.3.7 of the horizontal motion module, and a Y-axis motor 2.3.2 is installed on the front surface 2.3.6 of the horizontal motion module. The Y-axis motor end gear 2.3.4 is located at the end of the shaft of the Y-axis motor 2.3.2. The Y-axis motor end gear 2.3.4 cooperates with the crossbeam rack 2.2.1, and the horizontal motion module bottom surface sliders 2.3.1 and the horizontal motion module rear bottom surface sliders 2.3.3 cooperate with the crossbeam guide rail 2.2.2. Through the transmission method of gear rack and guide rail cooperation, the horizontal motion module 2.3 is driven to move in the Y direction. Y-axis limiting devices 2.3.5 are installed at both ends of the horizontal motion module 2.3 in the Y direction to avoid Y-axis collisions between the horizontal motion modules 2.3.

[0077] The lifting motion module 2.4 includes a lifting module 2.4.1, a lifting connector 2.4.2, a three-dimensional force sensor 2.4.3, and an angle-adjustable positioning component 2.4.4. The lifting module 2.4.1 is fixedly connected to the horizontal motion module 2.3 by bolts to drive the angle-adjustable positioning component 2.4.4 to move in the Z direction. The lifting connector 2.4.2 is fixedly connected to the lifting module 2.4.1 and the three-dimensional force sensor 2.4.3 by bolts. The three-dimensional force sensor 2.4.3 is fixedly connected to the angle-adjustable positioning component 2.4.4 by blind bolts to monitor the contact force data between the angle-adjustable positioning component 2.4.4 and the frame 8.

[0078] The internal structure of the angle-adjustable positioning component 2.4.4 is as follows: Figure 5 As shown, it includes an R-axis rotary table 2.4.4.1 and a swing structure 2.4.4.2. The lower outer wall of the R-axis rotary table 2.4.4.1 is fixedly connected to the three-dimensional force sensor 2.4.3 by blind bolts, and the upper outer wall is fixedly connected to the swing structure 2.4.4.2 by bolts. The outer side of the R-axis rotary table 2.4.4.1 is engraved with rotation scale to quantify the rotation angle. The swing structure 2.4.4.2 is provided with a rotation center hole 2.4.4.3, a locking hole 2.4.4.4, and a positioning hole 2.4.4.5. It can be connected to the frame 8 by connecting bolts through the positioning hole 2.4.4.5, thereby positioning the frame 8. The swing structure 2.4.4.2 is engraved with swing scale to quantify the swing angle. The rotation center hole 2.4.4.3 is located higher, and the locking hole 2.4.4.4 is located lower. This arrangement of the rotation center hole and locking hole results in a large locking arm, improving the reliability of positioning.

[0079] The conformal clamp 3 includes a stringer clamp 3.1 and a plate clamp 3.2, which are used to clamp the welds of the stringer 7 and the frame 8, and the plate 9 and the frame 8, respectively, to resist the deformation force during the welding process.

[0080] like Figure 6 As shown, in this embodiment, the conformal gripper 3 specifically includes:

[0081] The stringer clamp 3.1 and the plate clamp 3.2 all have a common clamp housing 3.3, conformal pad 3.4, clamp bolt 3.5, and clamp reinforcing rib 3.6. The conformal pad 3.4 is used to adapt to product surfaces with different curvatures and is connected to the clamp housing 3.3 by the clamp bolt 3.5. The stringer clamp 3.1 and the plate clamp 3.2 are used to clamp the stringer 7 and the plate 9, respectively. Their upper and lower surfaces are clamped by the clamp bolt 3.5. At the same time, multiple sets of clamp reinforcing ribs 3.6 are provided on the surface. The clamping holes of the clamp bolt 3.5 are located on the clamp reinforcing ribs 3.6 to improve the overall rigidity and clamping reliability of the conformal clamp 3.

[0082] The clamping support structure 4 has four parts, which are installed below the weld seam of the plate 9, such as... Figure 7 As shown, it includes a scissor lift structure 4.1, a waist-shaped groove 4.2, and a support platform; the lifting and lowering movement of the support platform is adjusted by the scissor lift structure 4.1, and the conformal clamp 3.2 of the support plate is connected to different positioning holes on the connecting fixture 2 through the waist-shaped groove 4.2 set on the surface of the base, so as to realize the flexible positioning of the clamp support structure 4.

[0083] The workbench 6 is placed around the inside of the pit 13, and the steel scaffolding 5 is placed on the workbench 6 along the Y direction of the system to provide workers with a stepping space. In this embodiment, the steel scaffolding 5 is in multiple sets of different specifications. After the connecting fixture 2 flexibly positions the skeleton parts of different configurations, steel scaffolding 5 of different specifications are placed in the gaps between the connecting fixtures.

[0084] The flexible tooling control system is installed on the pit 13 to issue command signals and control the entire tooling system to complete the flexible positioning of the aircraft frame and the prediction of post-weld deformation.

[0085] Flexible tooling control system, such as Figure 1 As shown, it specifically includes:

[0086] The system includes an electrical cabinet 10, an industrial computer 11, a PLC controller, and a bus coupling module. The PLC controller and the bus coupling module are installed inside the electrical cabinet 10. The electrical cabinet 10 also contains a motor driver and an air switch connected to the bus. The industrial computer 11 is connected to the PLC controller via a network cable. The PLC controller is connected to the motor driver via a bus. The motor driver is connected to the X-axis motor 2.1, the Y-axis motor 2.3.2, and the lifting module 2.4.1, respectively.

[0087] Furthermore, it should be noted that the XYZ directions of the tooling system designed in this application are as follows: Figure 1 As shown, with the ground rail 1 as the X direction, the direction directly opposite the positioning clamping hole 2.4.4.5 of the angle adjustable positioning component 2.4.4 is the positive X direction, the upward direction is the positive Z direction, and the crossbeam is the Y direction. The positive Y direction is obtained by the right-hand rule.

[0088] All motors in the flexible intelligent tooling system designed in this application have a braking mechanism with a braking torque greater than twice the rated torque, which can realize the tooling system locking when power is off.

[0089] The relative positioning accuracy between the parts of the fuselage frame after welding is required to be high, but the welding force generated during the welding process can cause the parts to deform, resulting in a reduction in welding accuracy. Therefore, this application designs a flexible positioning fixture for multi-configuration frames based on the structural characteristics of the aircraft frame; designs a conformal clamp at the weld seam to resist the welding deformation force; and develops a fixture control system with the function of predicting the deformation of parts after welding.

[0090] This concludes the description of the flexible intelligent tooling system designed in this application. The following embodiment also provides a control method for this system, specifically including:

[0091] S1. Input the control program into the industrial control computer 11 and connect it to the PLC controller. Establish the connection relationship between the control program and the X-axis motor 2.1, Y-axis motor 2.3.2, lifting module 2.4.1 and motor driver through the PLC controller.

[0092] S2. Import the workpiece model into the industrial computer 11 and automatically generate the coordinate position that the angle-adjustable positioning component 2.4.4 needs to move to. The industrial computer 11 sends a command signal to the PLC controller. The PLC controller controls the X-axis motor 2.1, Y-axis motor 2.3.2 and lifting module 2.4.1 connected to the fixture 2 to work, and controls the angle-adjustable positioning component 2.4.4 to move to the specified position.

[0093] S3. Hoisting and loading each frame component 8, using the adjustable positioning component 2.4.4 on the connecting fixture 2 to position the frame component 8, such as... Figure 9 As shown;

[0094] S4. Load each stringer 7, and clamp the stringer 7 to each frame member 8 using the stringer clamp 3.1, ensuring that the conformal curved surface of the conformal pad 3.4 is completely in contact with the outer surface of the workpiece during the clamping process. Figure 10 As shown;

[0095] S5. After the welding of stringers 7 and frame members 8 is completed and the post-weld heat treatment is finished, such as Figure 11 As shown, each plate 9 is fed in and clamped together with the frame 8 by the plate clamp 3.2. During the clamping process, the conformal curved surface of the pad 3.4 inside the plate clamp 3.2 is made to fit completely with the outer surface of the workpiece. The height of the clamp support structure 4 is adjusted to support the plate clamp 3.2.

[0096] S6. After all the plates have been heat-treated after welding, force monitoring data is obtained through the three-dimensional force sensor 2.4.3. The force monitoring data and prior data are fused to establish a Gaussian regression deformation prediction model. The deformation of the product after welding is predicted by the force monitoring data-post-weld deformation prediction method based on Gaussian process regression. The welding quality of the aircraft frame product is evaluated based on the deformation of the product.

[0097] As a preferred embodiment, such as Figure 8 As shown, step S6 specifically includes:

[0098] S61. Obtain prior data on the contact force between the angle-adjustable positioning component 2.4.4 and the frame component and the deformation of the component after welding through welding simulation of the skeleton parts;

[0099] More specifically, step S61 includes:

[0100] S611. In this embodiment, Catia is used to create a parametric model of the skeleton part, which includes the following features: manufacturing errors of the part positioning holes and welding areas; wherein the offset of the center of the positioning clamping hole in the XYZ direction and the offset of the V-groove angle of the welding area are defined as Gaussian distributed random variables with a mean of 0 and a standard deviation according to the process specification to ensure that the error space covers the actual manufacturing fluctuations.

[0101] S612. The Latin hypercube sampling method is used to generate n sets of process parameters, including welding speed, heat input, and clamping deviation of the welding area. A double ellipsoidal heat source model is defined through a Fortran subroutine. The six degrees of freedom of the part positioning clamping point are fully constrained in Abaqus software to simulate rigid fixation. At the same time, the welding conformal clamp adopts frictional contact and normal pressure contact coupling constraint to carry out welding simulation analysis of skeleton parts.

[0102] S613. Utilize multi-core parallelism to accelerate the solution and track model convergence in real time. Set the frame clamping point as the reference point, extract the post-weld deformation of the parts and the contact support reaction force at the positioning point from n sets of welding simulation data, and obtain the prior data for predicting the post-weld deformation of the skeleton parts.

[0103] S62. Using the contact force between the frame and the positioning component as the input feature and the post-weld deformation as the output feature, the radial basis kernel function is selected as the covariance function, and the hyperparameters in the covariance function are estimated using maximum likelihood estimation.

[0104] The formula for predicting post-weld deformation of a product is established based on the definition of a multivariate Gaussian distribution:

[0105]

[0106] Where y represents the product deformation data after welding in the prior data, and f * Here, μ(X) represents the product deformation data predicted by the Gaussian regression model, and μ(X) represents the mean of the contact force data in the prior data. * Let ) be the mean of the force monitoring data after actual welding, and K be the covariance function of all possible combinations of contact forces in the prior sample, which can be expressed by the formula:

[0107]

[0108] K * X for force monitoring data * The covariance function of all possible combinations of contact forces in the prior samples, i.e., K. * =[k(X * ,X1)k(X * ,X2)...k(X * ,X n )];K ** K is the covariance function of all possible combinations of force monitoring data. ** =[k(X * ,X * )];X n The nth contact force input from the prior sample;

[0109] Radial basis functions (RBFs) are fundamental to the effectiveness of Gaussian regression prediction models. RBFs are infinitely differentiable and can achieve nonlinear mappings, reducing model complexity compared to other commonly used polynomial kernel functions. Therefore, radial basis functions are chosen as the kernel function for the post-weld deformation prediction model, expressed by the following formula:

[0110]

[0111] Where l > 0 is the characteristic length scale of the covariance function, is a hyperparameter, and X i Input X for the i-th contact force sample in the prior samplesj Input the j-th contact force sample from the prior samples;

[0112] The hyperparameter l is solved using the maximum likelihood estimation method, which makes the RBF kernel function more suitable for the post-weld deformation prediction problem. The hyperparameter is learned by maximizing the log-likelihood function, which is as follows:

[0113]

[0114] Where θ is a hyperparameter such as length scaling l in the kernel function, and here θ = {l};

[0115] The gradient of the likelihood function, obtained by taking the partial derivative of the likelihood function, is:

[0116]

[0117] The hyperparameter l is updated using gradient optimization. The number of iterations is set to item. After item times of calculation, the hyperparameter l of the kernel function is obtained.

[0118] S63. Solve the post-weld deformation prediction formula based on the prediction model using the conditional Gaussian standard rule:

[0119]

[0120] in, This represents the uncertainty of the predicted deformation value; based on the condition that the post-weld deformation prediction data follows a multivariate Gaussian distribution, with the highest probability at the mean, the post-weld deformation data f of the aircraft frame product is then... * The best estimate is f * =μ(X) * )+K * K -1 (y-μ(X)).

[0121] The post-weld deformation prediction function of the tooling system designed in this invention uses post-weld force monitoring data to predict the deformation of parts after welding. Since the tooling is used for frame welding prototypes, there is no fixed value for its deformation tolerance threshold when conducting different welding experiments; this needs to be determined by the R&D personnel based on the specific circumstances. Furthermore, the deformation of parts can be further reduced through post-weld heat treatment. The post-weld deformation prediction method proposed in this invention can meet the requirements of intelligent tooling for predicting post-weld deformation in fuselage frame welding prototypes, thereby providing a basis for R&D personnel to evaluate the quality of the prototype and determine whether further heat treatment is needed to eliminate deformation.

[0122] S7. After welding is completed, when the aircraft frame product is removed from the frame, gradually loosen the clamps at the positioning points. In the industrial control computer 11, move the tooling system through manual operation mode and hoist the product out of the frame.

[0123] Thus, based on the flexible intelligent tooling system and control method proposed in this invention, the aircraft frame welding was completed, realizing flexible positioning of multi-configuration frame parts, clamping of the welding area, and prediction and quality assessment of post-weld deformation. Compared with the prior art, this invention can effectively improve the high-quality and rapid prototyping capability of aircraft frames, and enhance the development level of high-performance aircraft.

[0124] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0125] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An aircraft frame welding flexible intelligent tooling system with deformation prediction function, characterized in that, Specifically comprising: Ground rail (1), connecting tooling (2), conformal holder (3), holder support structure (4), steel jump plate (5), workbench (6) and flexible tooling control system; The ground rail (1) is provided with two symmetrically fixedly installed at both ends of the pit (13) Y direction, supporting and connecting tooling (2), and serving as the X direction movement axis base of the connecting tooling (2); The connecting tooling (2) has four, each connecting tooling (2) is installed on the ground rail (1), driving the inside angle adjustable positioning member (2.4.4) to move along XYZ three degrees of freedom; The conformal holder (3) includes stringer holder (3.1) and plate holder (3.2), respectively used to clamp the weld of stringer (7) and frame (8), and the weld of plate (9) and frame (8), to resist the deformation force in the welding process; The holder support structure (4) is provided with four, installed below the plate (9) weld, including scissors structure (4.1), waist type groove (4.2) and support platform; the support platform is adjusted to move up and down by the scissors structure (4.1), supporting the plate holder (3.2), and the different positioning holes on the connecting tooling (2) are connected through the waist type groove (4.2) arranged on the surface of the base, realizing the flexible positioning of the holder support structure (4); The workbench (6) is placed around the inside of the pit (13), and the steel jump plate (5) is placed on the workbench (6) along the system Y direction, providing a working stepping space for the workers; The flexible tooling control system is installed on the pit (13) to issue command signals and control the whole tooling system to complete the flexible positioning of the aircraft skeleton and the post-welding deformation prediction.

2. The aircraft frame welding flexible intelligent tool system with deformation prediction function according to claim 1, characterized in that, The ground rail (1) specifically comprises: Ground rail structure (1.1), ground rail guide rail (1.2), ground rail rack (1.3), leveling foot base (1.4) and ground rail reinforcing rib (1.5); the ground rail structure (1.1) serves as the base of the flexible intelligent tooling system and is welded with the leveling foot base (1.4); the leveling foot base (1.4) is placed on the surface of the pit (13), the X direction straightness of the ground rail (1) is adjusted by adding shims, the ground rail reinforcing rib (1.5) is arranged thereon to improve the overall stiffness of the ground rail; the ground rail guide rail (1.2) has two symmetrically arranged on the upper surface of the ground rail; the ground rail rack (1.3) is installed on the ground rail structure (1.1) through blind bolts; the tooling partition plate (14) is fixed at the front and rear ends of the ground rail to seal the front and rear of the ground rail (1) and prevent sundries from entering the inside of the tooling system.

3. The aircraft frame welding flexible intelligent tool system with deformation prediction function according to claim 2, characterized in that, Each connecting tooling (2) specifically comprises: X direction motor (2.1), cross beam (2.2), horizontal movement module (2.3), lifting movement module (2.4), wiring sheet metal (2.5), connecting tooling slider (2.6) and X direction limiting device (2.7); The crossbeam (2.2) is the main load-bearing component of the connecting tool (2), including crossbeam rack (2.2.1), crossbeam guide rail (2.2.2) and crossbeam structure (2.2.3), the bottom surface of the crossbeam (2.2) is installed with connecting tool slider (2.6) and X direction motor (2.1), the end of the rotating shaft of the X direction motor (2.1) is provided with X direction motor end gear (2.1.1); the X direction motor end gear (2.1.1) cooperates with the ground rail rack (1.3), the connecting tool slider (2.6) cooperates with the ground rail guide rail (1.2), through the transmission mode of gear rack and guide rail cooperation, the X direction movement of the connecting tool (2) is driven; the X direction limiting device (2.7) is installed at the two ends of the crossbeam (2.2) in X direction, to avoid the X direction collision of the connecting tool (2); The horizontal movement module (2.3) is provided with a plurality of horizontal movement modules along Y direction; in each horizontal movement module (2.3), the rear bottom surface (2.3.8) of the horizontal movement module is installed with two horizontal movement module rear bottom surface sliders (2.3.1), the back surface (2.3.7) of the horizontal movement module is installed with two horizontal movement module back surface sliders (2.3.3), the front surface (2.3.6) of the horizontal movement module is installed with Y direction motor (2.3.2), the end of the rotating shaft of the Y direction motor (2.3.2) is provided with Y direction motor end gear (2.3.4); the Y direction motor end gear (2.3.4) cooperates with the crossbeam rack (2.2.1), the horizontal movement module bottom surface slider (2.3.1) and the horizontal movement module back surface slider (2.3.3) cooperate with the crossbeam guide rail (2.2.2), through the transmission mode of gear rack and guide rail cooperation, the Y direction movement of the horizontal movement module (2.3) is driven; the Y direction limiting device (2.3.5) is installed at the two ends of the horizontal movement module (2.3) in Y direction, to avoid the Y direction collision between the horizontal movement modules (2.3); The lifting movement module (2.4) includes lifting module (2.4.1), lifting connecting piece (2.4.2), three-dimensional force sensor (2.4.3) and angle adjustable positioning piece (2.4.4); the lifting module (2.4.1) is fixedly connected with the horizontal movement module (2.3) through bolts, to drive the angle adjustable positioning piece (2.4.4) to move in Z direction; the lifting connecting piece (2.4.2) is fixedly connected with the lifting module (2.4.1) and the three-dimensional force sensor (2.4.3) through bolts; the three-dimensional force sensor (2.4.3) is fixedly connected with the angle adjustable positioning piece (2.4.4) through blind bolts, to monitor the contact force data of the angle adjustable positioning piece (2.4.4) and the frame (8).

4. The aircraft frame welding flexible intelligent tool system with deformation prediction function according to claim 2, characterized in that, The contour gripper (3) specifically comprises: The stringer clamp (3.1) and the plate clamp (3.2) are used for clamping the stringer (7) and the plate (9) respectively, the upper and lower surfaces thereof are clamped through the clamp bolt (3.5), and a plurality of clamp reinforcing ribs (3.6) are arranged on the surfaces, the clamp hole of the clamp bolt (3.5) is arranged on the clamp reinforcing rib (3.6), and the overall rigidity of the profiled clamp (3) and the clamping reliability are improved.

5. The aircraft frame welding flexible intelligent tool system with deformation prediction function according to claim 3, characterized in that, Adjacent two connecting tools (2), the outermost connecting tool (2) and the tool partition plate (14), adjacent two horizontal movement modules (2.3), and the outermost horizontal movement module (2.3) and the cross beam (2.2) are all provided with telescopic dustproof organ cases (12), the organ case (12) and the tool partition plate (14) are used for protecting the mechanical structure and electrical elements inside the tool system, and avoiding sundries from falling into the tool system.

6. The aircraft frame welding flexible intelligent tool system with deformation prediction function according to claim 3, characterized in that, The angle-adjustable positioning member (2.4.4) specifically comprises: The R-axis rotating table (2.4.4.1) and the swing structure (2.4.4.2); the lower end outer wall of the R-axis rotating table (2.4.4.1) is fixedly connected with the three-dimensional force sensor (2.4.3) through blind bolts, and the upper end outer wall is fixedly connected with the swing structure (2.4.4.2) through bolts; the R-axis rotating table (2.4.4.1) is engraved with a rotating scale on the outer side, for quantifying the rotating angle; the swing structure (2.4.4.2) is provided with a rotating center hole (2.4.4.3), a locking hole (2.4.4.4) and a positioning hole (2.4.4.5), and a connecting bolt can be used to connect the frame (8) through the positioning hole (2.4.4.5), so as to position the frame (8); the swing structure (2.4.4.2) is engraved with a swing scale, for quantifying the swing angle; and the rotating center hole (2.4.4.3) is located at the upper side, and the locking hole (2.4.4.4) is located at the lower side.

7. The aircraft frame welding flexible intelligent tool system with deformation prediction function according to claim 6, characterized in that, The flexible tool control system comprises: The electrical cabinet (10), the industrial computer (11), the PLC controller and the bus coupling module; the PLC controller and the bus coupling module are installed in the electrical cabinet (10), the electrical cabinet (10) is further provided with a motor driver and an air switch arranged on the bus; the industrial computer (11) is connected with the PLC controller through a network cable, the PLC controller is connected with the motor driver through the bus, and the motor driver is connected with the X-direction motor (2.1), the Y-direction motor (2.3.2) and the lifting module (2.4.1) respectively.

8. The control method of the aircraft frame welding flexible intelligent tool system with deformation prediction function according to any one of claims 1-7, characterized in that, Specifically comprising the following steps: S1, input control program on the industrial computer (11) and connect with PLC controller, through the PLC controller to establish the connection relationship between the control program and X motor (2.1), Y motor (2.3.2) and lifting module (2.4.1) and motor driver; S2, the workpiece number model is imported into the industrial computer (11), and the coordinate position to which the angle adjustable positioning member (2.4.4) needs to be moved is automatically generated. The industrial computer (11) sends instruction signals to the PLC controller, and the PLC controller controls the X motor (2.1), Y motor (2.3.2) and lifting module (2.4.1) connected with the tooling (2) to work, and controls the angle adjustable positioning member (2.4.4) to move to the specified position; S3, hoist and load each frame member (8), and position the frame member (8) through the angle adjustable positioning member (2.4.4) on the tooling (2); S4, load each stringer (7), clamp the stringer (7) and each frame member (8) together through the stringer clamp (3.1), and ensure that the conformal surface of the conformal pad (3.4) is completely attached to the outer surface of the workpiece during clamping; S5, after the stringer (7) and the frame member (8) are welded and postweld heat treatment is completed, load each plate member (9), clamp the plate member (9) and the frame member (8) together through the plate clamp (3.2), and ensure that the conformal surface of the conformal pad (3.4) is completely attached to the outer surface of the workpiece during clamping. Adjust the height of the clamp support structure (4) to support the plate clamp (3.2); S6, after all the plate members are postweld heat treated, obtain force monitoring data through the three-dimensional force sensor (2.4.3), fuse the force monitoring data and prior data to establish a Gaussian regression deformation prediction model, predict the postweld deformation of the product through the force monitoring data-postweld deformation prediction method based on Gaussian process regression, and evaluate the welding quality of the aircraft framework product according to the deformation of the product; S7, after the welding is completed, gradually loosen the clamping of the positioning points, and move the tooling system through the manual control mode in the industrial computer (11) to hoist and load the product out of the rack.

9. The control method of the aircraft frame welding flexible intelligent tool system with deformation prediction function according to claim 8, characterized in that, Step S6 specifically includes the following steps: S61, obtain n groups of contact force of the angle adjustable positioning member (2.4.4) and the frame member (8) and prior data of the part postweld deformation through framework part welding simulation; S62, take the contact force of the frame member (8) and the positioning member as the input feature, and take the postweld deformation as the output feature. Select a radial basis kernel function as the covariance function, and use maximum likelihood estimation for the hyperparameters in the covariance function. The prediction formula for the product postweld deformation is defined through multivariate Gaussian distribution as follows: where y represents the product post-weld distortion data in the prior data, f * is the product distortion data predicted by the Gaussian regression model, μ(X) is the mean of the contact force data in the prior data, μ(X * ) is the mean of the actual post-weld force monitoring data, K is the covariance function of all possible combinations of contact forces in the prior sample, K * is the covariance function of the force monitoring data X * and all possible combinations of contact force inputs in the prior sample, and K ** is the covariance function of all possible combinations of force monitoring data. S63, according to the conditional Gaussian standard rule, solve the postweld deformation prediction formula based on the prediction model: wherein, represents the uncertainty of the predicted deformation value; according to the post-weld deformation prediction data, the condition conforms to the multivariate Gaussian distribution, the probability is maximum at the mean value, and then the best estimate of the post-weld deformation data f * of the aircraft framework product is f * = μ(X * ) + K * K -1 (y - μ(X)).

10. The control method of the aircraft frame welding flexible intelligent tool system with deformation prediction function according to claim 9, characterized in that, Step S61 specifically includes: S611, create a parameterized model of the framework part, which includes the following features: manufacturing errors of part positioning holes and welding areas; wherein the offset amount of the positioning clamping hole center in XYZ direction and the offset amount of the V-shaped groove angle of the welding area are defined as Gaussian distribution random variables, with a mean of 0 and a standard deviation according to the process specification to ensure that the error space covers the actual manufacturing fluctuations. S612, Latin hypercube sampling method is used to generate n groups of process parameters, including welding speed, heat input, and welding area clamping deviation, and a skeleton part welding simulation analysis is performed; S613, the part post-weld deformation and the contact support reaction force at the positioning point of the n groups of welding simulation data are extracted to obtain the prior data for predicting the post-weld deformation of the skeleton part.

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