Efficient automatic fiber placement forming method for L-shaped end frame of composite rotary shell

Abstract

The application provides a kind of composite rotary shell L type end frame efficient automatic fiber placement forming method, comprising: the core mold installation is optimized from the flanging surface being perpendicular to the clamping spindle to the flanging surface being parallel to the clamping spindle, the original spindle system is optimized from the original rotating mold to the swing mold, the core mold is fixedly connected by V shaft and clamping spindle U shaft, and the flanging surface faces the fiber placement head;Pasting tool is connected by V shaft and clamping spindle U shaft, V shaft and pasting tool rotate with clamping spindle U shaft during laying;The circumferential layer is divided into multiple parts, and the circumferential layer is realized by using the fixed area laying method: the fiber placement head fixed area laying, after each layer is laid, the V shaft is rotated to the next layer for laying, and the layers are laid in turn, and finally the circumferential layer is completed.The application solves the problem of collision interference between the fiber placement head and the mold, mechanical arm and the like during the laying of the end frame.

Description

Technical Field

[0001] This invention belongs to the field of composite material molding technology, and in particular, it is a method for efficient automatic fiber placement molding of L-shaped end frames of composite rotating shells. Background Technology

[0002] Carbon fiber composites, due to their lightweight and high strength, have become a primary structural material for aerospace vehicles, with their applications and quantities increasing year by year, and they have found even wider use in aircraft compartments. Complex irregular curved surfaces, cones, cylinders, and other rotating structures with L-shaped end frames are frequently used structural forms. Automated fiber placement technology, due to its high production efficiency and strong ability to manufacture complex structures, has become one of the advanced manufacturing technologies in aerospace.

[0003] However, the curved surface of the rotating shell folds and converges towards the axis at the end frame flange. On the one hand, due to the large curvature and non-developable characteristics of the flange, the flange is prone to collision interference, as well as various defects such as filament twisting and gaps due to unreasonable posture. On the other hand, due to the limitations of the main body structure and mechanical structure of the automatic filament placement equipment, the drastic changes in posture during end frame placement can easily cause collision interference between the filament placement head and the mold, robotic arm, etc.

[0004] Existing solutions, which optimize placement posture and collision avoidance by automatically placing post-mounted modules based on endframe features, have difficulty solving the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a highly efficient automatic filament placement method for L-shaped end frames of composite rotating shells, in order to solve the problems of collision interference, filament twisting, and gap defects caused by the limitations of the main body structure of existing automatic filament placement equipment and the large changes in the curvature of the flange during the placement of L-shaped end frames of composite rotating shells.

[0006] The technical solution to achieve the purpose of this invention is as follows:

[0007] A highly efficient automated filament placement method for forming L-shaped end frames of composite rotating shells includes:

[0008] The core mold installation was optimized from the flange surface being perpendicular to the clamping spindle to the flange surface being parallel to the clamping spindle. The original rotating mold was optimized to an oscillating mold using the original spindle system. The core mold is fixedly connected to the clamping spindle U-axis via the V-axis, with the flange surface facing the filament laying head.

[0009] The laying fixture is connected to the clamping spindle U-axis via a V-axis. During laying, the V-axis and the laying fixture rotate with the clamping spindle U-axis.

[0010] The circumferential layup is divided into multiple parts and a fixed area layup method is used to achieve the circumferential layup: the layup head is laid in a fixed area, and after each layup is completed, the die is rotated through the V-axis to the next layup for layup. The layup is carried out in this way until all circumferential layups are completed.

[0011] The significant advantages of this invention compared to existing technologies are:

[0012] (1) This invention does not require modification of existing automatic filament placement equipment and solves the problem of collision and interference between the filament placement head and the mold, robotic arm, etc. during end frame placement. The forming fixture involved in this invention utilizes the original spindle system to optimize the original rotating mold into an oscillating mold. The coupled motion with the filament placement head reduces the curvature change, thereby avoiding drastic changes in posture during end frame placement. At the same time, the reduced stroke variation of each axis of the robot improves the placement efficiency.

[0013] (2) The tooling and flange path planning algorithm involved in this invention enable the fixed area of ​​the rotating body to be laid and complete the circumferential full-layer laying. The fixed area laying always maintains a small range of posture changes, reduces filament twisting and gap defects, and has higher laying efficiency. Attached Figure Description

[0014] Figure 1 This is a diagram illustrating the effect of collision interference.

[0015] Figure 2 This is a schematic diagram of the laying plan and tooling.

[0016] Figure 3 This is a schematic diagram of the fixed laying area.

[0017] Figure 4 This is a schematic diagram of path planning and post-partitioning processing.

[0018] Figure 5 A simulation image showing the effect of laying out a fixed laying area. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0020] This embodiment presents an automatic wire-layout forming method for an L-shaped end frame of a composite rotating shell, taking a composite cylindrical shell with a large-angle flange as an example. The shell has an L-shaped end frame with a skin that is radially inwardly flanged. The specific steps are as follows:

[0021] Step 1: Laying-out Simulation Analysis. Based on robot simulation software, simulation models are created for the on-site spindle platform, guide rails, robot, and filament placement head. Laying-out simulation, collision checking, and NC program output are performed by importing tooling models and laying-out paths. For example... Figure 1 As shown, when laying the end frame of the rotating housing, the filament laying head at the flange is prone to collision and interference with the robotic arm.

[0022] Step 2: Optimization of the placement scheme. To achieve edge-flipping placement of the rotating end frame, the limitations of the automatic filament placement equipment's main structure and the mechanical structure of the filament placement head, as well as the collision and interference problem between the filament placement head and the mold and robotic arm caused by drastic posture changes during end frame placement, must be addressed first. The optimization idea of ​​this invention is as follows:

[0023] (a) First, the core mold installation was optimized from having the flanging surface perpendicular to the clamping spindle to having the flanging surface parallel to the clamping spindle. This involves optimizing the existing spindle system from a rotating mold to a swinging mold. The coupled movement of the filament placement head and the mold reduces curvature changes during flanging, thus solving the interference and collision problem of the flanging filament placement head. For example... Figure 2 The core mold is fixedly connected to the clamping spindle U-axis via the V-axis, with the flanged surface facing the filament laying head;

[0024] (b) Further optimization: such as Figure 3 The circumferential layup is divided into four quadrants and implemented using a fixed-area layup method. The process involves rotating the mandrel around the V-axis, placing the filament placement head in a fixed area (quadrant I, 1 / 4 facing the head). After each 1 / 4 layup, the mandrel is rotated 90° along the V-axis to the fixed area for the next 2 / 4 layup. The 3 / 4 and 4 / 4 layups are then performed sequentially until all circumferential layups are completed. This method avoids potential interference between the filament placement head and mandrel outside the designated layup area and also reduces the travel distance of the robotic arm, thus improving layup efficiency.

[0025] (c) The laying fixture is supported by the main spindle (U-axis) and connected to the main spindle (U-axis) via the V-axis. During laying, the V-axis and the laying fixture rotate with the main spindle (U-axis), and the overall rigidity design meets the laying requirements. The specific clamping method of the mold main spindle (U-axis) is optimized according to step 3 to obtain the fixture (core mold, chuck clamping) parameters.

[0026] Step 3: Tooling Optimization. Based on the placement scheme in Step 2, the tooling design parameters comprehensively consider the equipment's motion envelope space, mold dimensions, and the placement trajectory design at various angles to ensure that the rotating shell can be fully laid up. An example is shown below:

[0027] (a) First, design the maximum area that can be laid: such as a 45-degree ply circumferential ply with a fixed laying area angle θ.

[0028] (b) Taking any edge boundary point on both sides of the laying angle θ region as the trajectory starting point, the skin region uses the geodesic method to generate a 45° skin trajectory line, and the edge region uses the natural path method to generate an edge trajectory line. The above trajectory lines constitute the outermost 45° laying center trajectory line of the fixed laying area and are imported into the simulation software.

[0029] (c) Import the core mold CAD model (the surface model of the core mold to be laid) and perform layability simulation; continuously adjust the tooling parameters h, L1, and L2 to ensure that no collision or interference occurs during the laying process on the outermost laying path of the fixed laying area, and observe the changes in the travel of each axis of the end frame. The trajectory can be adjusted as needed (regenerate the trajectory line according to step b and continue simulation optimization). Wherein, h is the distance from the core mold boundary to the main spindle U-axis, and L1 and L2 are the distances from the clamping positions of the two end chucks to the core mold boundary, respectively.

[0030] (d) Using the trajectory line generation method in (b), the maximum layup area layup trajectory design for plies at angles of 45°, -45°, and 0° is carried out sequentially. Layupability simulation is performed using step 1. For each angle ply, the tooling parameters and layup angle θ are continuously optimized. The intersection of the tooling parameters and layup angle θ is obtained to ensure that the tooling design meets the requirements of layup at each angle, while avoiding collision interference and ensuring reasonable and efficient changes in the stroke of each axis of the end frame.

[0031] Step 4: Laying out the filament head and post-processing of zones. To achieve fixed-area laying of the filament head in Step 2 and realize circumferential full coverage, the laying strategy and path algorithm need to be optimized simultaneously. (See attached...) Figure 4 The specific process is as follows:

[0032] (a) Using any boundary point on the flange as the starting point of the trajectory, the skin trajectory line is generated using the geodesic method in the skin area, and the flange trajectory line is generated using the natural path method in the flange area. The two trajectory lines are the initial path N1, and other paths are generated by rotating the initial path by a certain angle to generate other laying paths N2, N3...N i , where i is the number of center trajectories, calculate the key points of yarn feed interruption for each trajectory.

[0033] (b) Re-partitioning of the laying path. Based on the fixed laying area angle θ determined in step 3, divide all laying paths into regions α1, α2…α j j is the number of partitions, and θ is the angle between each partition. αj θ must be satisfied αj <θ.

[0034] (c) The partitioned path is rotated to the fixed laying area. The post-processing module of the trajectory software mainly calculates the laying trajectory and key I / O points, and outputs the trajectory NC file. α2, α3…α… are calculated respectively. j The angle φ between the angle bisector of the area to be paved and the angle bisector of the fixed paving area (α1) (fixed area reference line) j α j All trajectories contained in the region are rotated by φ j The position is adjusted to a fixed placement area, the placement path points and key points are recalculated, and the output NC_j trajectory file is updated; this is done in conjunction with V-axis rotation φ. jIt can achieve fixed-area laying of the filament head and full circumferential coverage.

[0035] Step 5: Simulation and shaping of the end frame of the rotating body. Based on the tooling parameters obtained in Step 3 and the trajectory planning results in Step 4, a placement simulation is performed, such as... Figure 5 To ensure a fixed-area laying effect, the end frames were laid without collisions or interference and maintained a small range of posture changes. Finally, the NC program was output and the process parameters were set for laying and shaping.

Claims

1. A highly efficient and automated filament-laying method for forming an L-shaped end frame of a composite rotating shell, characterized in that, include: The core mold installation was optimized from the flange surface being perpendicular to the clamping spindle to the flange surface being parallel to the clamping spindle. The original rotating mold was optimized to an oscillating mold using the original spindle system. The core mold is fixedly connected to the clamping spindle U-axis via the V-axis, with the flange surface facing the filament laying head. The laying fixture is connected to the clamping spindle U-axis via a V-axis. During laying, the V-axis and the laying fixture rotate with the clamping spindle U-axis. The circumferential layup is divided into multiple parts and a fixed area layup method is used to achieve the circumferential layup: the layup head is laid in a fixed area, and after each layup is completed, the die is rotated through the V-axis to the next layup for layup. The layup is carried out in this manner until all circumferential layups are completed. The tiling fixture design includes: (1) First, set the circumferential ply fixed ply area and the ply angle θ; (2) Taking any edge upper boundary point on both sides of the laying angle θ region as the starting point of the trajectory, the skin region uses the geodesic method to generate the skin trajectory line of the laying angle θ, and the edge region uses the natural path method to generate the edge trajectory line. The above trajectory lines constitute the laying center trajectory line of the outermost part of the fixed laying area. (3) Import the core mold digital model and perform layability simulation; continuously adjust the tooling parameters h, L1, L2 to ensure that the core mold does not collide or interfere during the laying process of the outermost laying path in its fixed laying area; where h is the distance from the core mold boundary to the main spindle U axis, and L1 and L2 are the distances from the clamping positions of the two end chucks to the core mold boundary, respectively. (4) Using the trajectory line generation method in step (2), the maximum laying area laying trajectory design of different angle plies is carried out in sequence, and the layability simulation is performed. For each angle ply, the tooling parameters and laying angle θ are continuously optimized, and the intersection of the tooling parameters and laying angle θ is obtained to ensure that the tooling design meets the requirements of laying plies at each angle. To achieve fixed-area placement of the filament placement head and full circumferential coverage, the placement strategy and path algorithm need to be optimized simultaneously, including: (a) Taking any boundary point on the flange as the starting point of the trajectory, the skin trajectory line is generated by the geodesic method in the skin area and the flange trajectory line is generated by the natural path method in the flange area. The two trajectory lines are the initial paths. Other paths are generated by rotating the initial path by a set angle. , … , Calculate the key points of yarn interruption for each trajectory based on the number of central trajectories; (b) Re-partitioning of the laying path: Based on the determined fixed laying area and the laying angle θ, the entire laying path is divided into regions. , … , The number of zones, and the included angle of each zone. Must meet ; (c) Rotate the partitioned path to the fixed laying area: calculate separately , … The angle bisector of the area to be laid and the fixed laying area The angle between the angle bisectors , respectively All trajectories contained in the area are rotated. Once the target area is reached, the placement trajectory and key points are recalculated, and the output NC_ is updated. Track file; coordinated with V-axis rotation It can achieve fixed-area laying of the filament head and full circumferential coverage.

2. The efficient automatic filament placement method for L-shaped end frames of composite rotating shells according to claim 1, characterized in that, It also includes laying simulation based on the acquired tooling parameters and trajectory planning results, and finally outputting the NC program and setting the process parameters for laying and forming.

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