Wideband automatic lay-up near-net-shape forming method for large convex and concave curved hull

Abstract

The present invention discloses a method for near-net-shape forming of a large-scale convex-concave curved surface fused special-shaped cabin with wide band automatic laying, which belongs to the field of composite material structure design and forming process. Specifically, it relates to a series of heat-insulating composite fiber mesh cloth tapes, and a laying and forming process method for various complex skin structural parts such as spatial axisymmetric, plane-symmetric, non-axisymmetric, and special-shaped convex-concave curved surfaces through cyclic laying, reciprocating laying, overlapping laying, etc. It mainly includes a series of key common technologies for laying two different shapes of convex-concave curved surface fused special-shaped cabins respectively using two resins with different viscosities, and the design and optimization of the near-net-shape laying trajectory of a large-scale convex-concave curved surface fused special-shaped cabin. It includes the trajectory generation and post-processing technology based on mesh surface trajectory planning and spiral line-surface intersection method, the control of key laying technical parameters such as the optimal cloth width and overlap amount of reciprocating cyclic laying, and the seven-axis RTCP optimization control concept and implementation method based on speed optimization acceleration and deceleration disturbance control.

Description

Technical Field

[0001] The present invention discloses a method for near-net-shape forming of a large-scale convex-concave curved surface fused special-shaped cabin with wide band automatic laying, which belongs to the field of composite material structure design and forming process. Specifically, it relates to a series of heat-insulating composite fiber mesh cloth tapes, and a laying and forming process method for various complex skin structural parts such as spatial axisymmetric, plane-symmetric, non-axisymmetric, and special-shaped convex-concave curved surfaces through cyclic laying, reciprocating laying, overlapping laying, etc. It mainly includes a series of key common technologies for laying two different shapes of convex-concave curved surface fused special-shaped cabins respectively using two resins with different viscosities, and the design and optimization of the near-net-shape laying trajectory of a large-scale convex-concave curved surface fused special-shaped cabin. It includes the trajectory generation and post-processing technology based on mesh surface trajectory planning and spiral line-surface intersection method, the control of key laying technical parameters such as the optimal cloth width and overlap amount of reciprocating cyclic laying, and the seven-axis RTCP optimization control concept and implementation method based on speed optimization acceleration and deceleration disturbance control. Background Art

[0002] With the development of aerospace, cabins are common components of aircraft. Their preparation methods and technologies are related to the performance of aircraft. The current cabin preparation technologies include traditional three-axis CNC winding machines. Traditional three-axis CNC winding machines can complete the winding of composite skins of cylindrical, conical, and power curve-shaped rotational bodies, but cannot complete the laying of special-shaped curved skins. Traditional three-axis cloth tape winding machines can only complete mold rotation and prepreg tape fixation. The laying of cloth tapes is done manually, and the prepreg tapes are mostly manually applied with tension during laying, such as Figure 3 As shown in the figure, manual laying will lead to poor fit between the cloth tape and the mold product, which is larger than the theoretical circumference and brings various product quality defects such as wrinkles, breaks, delamination, and bridging. The main disadvantages of parallel overlapping winding of fiber mesh cloth and diagonal winding of twill cloth after curing are as follows:

[0003] (1) After curing and molding, there are various quality defects such as wrinkles, bridging, delamination, and cracking, resulting in poor product quality reliability, stability, and consistency;

[0004] (2) Low material utilization leads to high material costs. The material utilization rate of traditional winding molding is less than 30%, and a large area of ​​material is cut off after curing, resulting in extremely serious waste;

[0005] (3) It needs to be removed by mechanical cutting, and fiber cutting and damage lead to low comprehensive performance, high processing cost, serious cutting dust pollution, and long process turnover cycle, resulting in high overall cost and long cycle.

[0006] At present, in order to solve the above problems, the better solution is to adopt automatic wide tape laying technology. However, the current technical tracking and exploration research on this technology has not conducted systematic research on automatic tape laying equipment, laying and forming process technology and corresponding prepreg tape preparation technology. This has brought great difficulties to the engineering application of this forming technology, and it is very easy to cause defects in the product quality of the cabin material and a long preparation cycle.

[0007] At the same time, except for the thin-walled composite skin structure components of the rotating body shell, which can be wound by the tape winding machine, there is no automated equipment for the forming of thin-walled composite products with complex and irregular curved surfaces. Most of them need to be formed manually. The manual forming method has a great impact on the laying direction, accuracy and laying quality of the composite skin fiber on the comprehensive performance and quality consistency of the product. The specific reason is that manual laying has the following requirements:

[0008] (1) First, the mold needs to be preheated to ensure that the prepreg can be well attached to the mold; the angle and gap splicing of the prepreg tow are manually controlled;

[0009] (2) In order to ensure good adhesion between prepregs, vacuum packing and pre-pressing are required every 2 to 3 layers;

[0010] (3) The mold needs to be preheated before the next layer is laid. The prepreg that has been laid on the mold often needs to go through multiple heating processes.

[0011] Therefore, the above requirements lead to the disadvantages of long cycle, high labor intensity and low efficiency in the manual molding process. In addition, the fiber placement angle, seams between fiber bundles, resin content of prepreg, fiber straightening degree, etc. of the manually molded composite structural parts cannot be guaranteed. The product quality stability is poor and cannot meet the engineering high-efficiency production rhythm requirements of composite material space curved surface skin products.

[0012] Therefore, how to improve the laying quality of the cabin based on automatic wide tape laying technology is a technical problem that needs to be solved urgently. Summary of the invention

[0013] The present application provides a special-shaped cabin with a high lift-to-drag ratio aerodynamic appearance and a preparation method thereof, so as to solve the technical problem in the prior art that the laying quality of the cabin cannot be improved based on the automatic wide tape laying technology.

[0014] In a first aspect, a method for near-net-shape forming of a large-scale convex-concave curved fusion special-shaped cabin with wide-band automatic lay-up, the method comprising:

[0015] The special-shaped cabins with convex and concave surfaces of different structural forms are analyzed to obtain the laying trajectory of the special-shaped cabin surface;

[0016] The curved surface is automatically laid and wound in a circular manner, and then solidified to obtain a large-scale convex and concave curved surface fused special-shaped cabin;

[0017] Wherein, the special-shaped cabin includes special-shaped cabin I and special-shaped cabin II;

[0018] The automatic laying and wrapping includes: automatic laying and wrapping near net shape laying by cyclic winding with eight-axis and seven-axis linkage automatic laying and wrapping equipment under RTCP control conditions;

[0019] The automatic laying and winding methods include vertical laying and winding and horizontal laying and winding;

[0020] The raw materials for the automatic laying and winding include resin and cloth tape, and the structure of the cloth tape is plain cloth or variable twill cloth;

[0021] The thickness of the automatically laid resin is 5 mm to 16 mm, and the width of the automatically laid cloth tape is 40 mm to 80 mm.

[0022] Optionally, the resin used for laying and wrapping the special-shaped cabin body I is semi-ceramic modified phenolic resin WBFC-20, and the cloth tape used for laying and wrapping the special-shaped cabin body I is B-type quartz fiber; the structure of the cloth tape used for laying and wrapping the special-shaped cabin body I is a large deformation twill cloth in the warp 45° and weft 45° directions;

[0023] The resin used for laying and wrapping the special-shaped cabin II is a modified phenolic resin, and the cloth tape used for laying and wrapping the special-shaped cabin II is a C-type quartz fiber;

[0024] The structure of the fabric tape used for laying and wrapping the special-shaped cabin II is a small-deformation twill fabric in the directions of warp 0° and weft 90°.

[0025] Optionally, the semi-ceramic modified phenolic resin WBFC-20 satisfies: Powder particle size distribution: D 50 <5.5μm, resin content: 52±3%, insoluble content: 14±2%, viscosity at 25℃: 350±50mPa*s, gel time at 150℃: 130±20s, free phenol content<10%;

[0026] The quartz fiber content of the B-type quartz fiber is greater than 99%, and the quartz fiber content of the C-type quartz fiber is greater than 99%.

[0027] Optionally, the automatic laying includes: performing automatic laying and near-net-shape laying based on the principles of fiber tape continuity, no cutting after laying, and axial performance priority;

[0028] The near-net-shape automatic laying includes unidirectional cyclic laying and bidirectional cyclic reciprocating laying;

[0029] The one-way cycle laying and wrapping includes vertical laying and wrapping from top to bottom or from bottom to top, and the one-way cycle laying and wrapping also includes horizontal laying and wrapping from small end to large end or from large end to small end;

[0030] The bidirectional circular reciprocating paving and wrapping includes vertical paving and wrapping from top to bottom or from bottom to top, and the bidirectional circular reciprocating paving and wrapping also includes horizontal paving and wrapping from the small end to the large end or from the large end to the small end.

[0031] Optionally, the special-shaped cabin body I is composed of a front cabin body and a rear cabin body that are fused together to form a plane-symmetrical special-shaped shell with convex and concave surfaces. The front cabin body and the rear cabin body are both composed of a plurality of groups of convex surfaces with positive curvature and a plurality of groups of concave surfaces with negative curvature that are fused together, wherein the convex surfaces with positive curvature and the concave surfaces with negative curvature are both formed by a plurality of groups of smooth arcs fused together by spline interpolation.

[0032] Optionally, a two-dimensional coordinate system of the special-shaped cabin body I is constructed with the center point of the central axis from the highest point to the lowest point of the cross section of the special-shaped cabin body I as the origin, and the front section cabin body is divided into a plurality of groups of front section convex curved surfaces and a plurality of groups of front section concave curved surfaces according to the two-dimensional coordinate system of the special-shaped cabin body I, and the front section convex curved surfaces and the front section concave curved surfaces are symmetrically arranged one by one;

[0033] The front convex surface includes a first front convex surface in quadrant I, a second front convex surface in quadrant II, a third front convex surface in quadrant III, and a fourth front convex surface in quadrant IV; the front concave surface includes a first front concave surface, a second front concave surface, a third front concave surface, and a fourth front concave surface; the first front concave surface is located at the intersection of quadrant I and quadrant II, the second front concave surface is located at the intersection of quadrant II and quadrant III, the third front concave surface is located at the intersection of quadrant III and quadrant IV, and the fourth front concave surface is located at the intersection of quadrant IV and quadrant I;

[0034] The first front section concave curved surface fuses the first front section convex curved surface and the second front section convex curved surface, and the second front section concave curved surface fuses the fourth front section convex curved surface and the first front section convex curved surface;

[0035] The third front section concave curved surface fuses the second front section convex curved surface and the third front section convex curved surface, and the fourth front section concave curved surface fuses the third front section convex curved surface and the fourth front section convex curved surface;

[0036] The curvature change degree of the first front section concave curved surface or the second front section concave curved surface is greater than the curvature change degree of the third front section concave curved surface or the fourth front section concave curved surface;

[0037] The rear section cabin body is divided into a plurality of groups of rear section convex curved surfaces and a plurality of groups of rear section concave curved surfaces according to the cross section of the two-dimensional coordinates, and the rear section convex curved surfaces and the rear section concave curved surfaces are symmetrically arranged one by one;

[0038] The rear convex surface includes a first rear convex surface in quadrant I, a second rear convex surface in quadrant II, a third rear convex surface in quadrant III, and a fourth rear convex surface in quadrant IV; the rear concave surface includes a first rear concave surface, a second rear concave surface, a third rear concave surface, and a fourth rear concave surface; the first rear concave surface is located at the intersection of quadrant I and quadrant II, the second rear concave surface is located at the intersection of quadrant II and quadrant III, the third rear concave surface is located at the intersection of quadrant III and quadrant IV, and the fourth rear concave surface is located at the intersection of quadrant IV and quadrant I;

[0039] The first rear section concave curved surface fuses the first rear section convex curved surface and the second rear section convex curved surface, and the second rear section concave curved surface fuses the fourth rear section convex curved surface and the first rear section convex curved surface;

[0040] The third rear concave surface fuses the second rear convex surface and the third rear convex surface, and the fourth rear concave surface fuses the third rear convex surface and the fourth rear convex surface;

[0041] The curvature change degree of the first rear concave curved surface or the second rear concave curved surface is greater than the curvature change degree of the third rear concave curved surface or the fourth rear concave curved surface;

[0042] A first rounded convex surface is provided between the second rear-segment convex surface and the first rear-segment concave surface, a second rounded convex surface is provided between the second rear-segment convex surface and the third rear-segment concave surface, a third rounded convex surface is provided between the fourth rear-segment convex surface and the second rear-segment concave surface, a fourth rounded convex surface is provided between the fourth rear-segment convex surface and the fourth rear-segment concave surface, the first rounded convex surface and the second rounded convex surface are relatively symmetrically arranged in quadrants I and III, the third rounded convex surface and the fourth rounded convex surface are relatively symmetrically arranged in quadrants II and IV, and the curvature variation degree of the first rounded convex surface or the second rounded convex surface is less than that of the third rounded convex surface or the fourth rounded convex surface;

[0043] The first rear-section convex surface, the second rear-section convex surface, the third rear-section convex surface, the fourth rear-section convex surface, the first rear-section concave surface, the second rear-section concave surface, the third rear-section concave surface, the fourth rear-section concave surface, the first rounded convex surface, the second rounded convex surface, the third rounded convex surface and the fourth rounded convex surface form a large end surface, the second rear-section convex surface forms a first triangular surface together with the first rounded convex surface and the second rounded convex surface in a direction away from the large end surface, and the fourth rear-section convex surface forms a second triangular surface together with the third rounded convex surface and the fourth rounded convex surface in a direction away from the large end surface.

[0044] Optionally, the front section cabin body and the rear section cabin body are both in a double cone shape, the longitudinal projection surface of the front section cabin body includes a group of symmetrical front section symmetric surfaces, and the semi-cone angle of the height change of the front section symmetric surfaces is 4.2°;

[0045] The longitudinal projection surface of the rear section cabin body includes a group of symmetrical rear section symmetric surfaces, and the semi-cone angle of the height change of the rear section symmetric surfaces is 1.3°;

[0046] The semi-cone angle of the height change of the third front section convex surface is 2.5°, the semi-cone angle of the height change of the first front section convex surface is 5.6°, the semi-cone angle of the height change of the third rear section convex surface is 3°, and the semi-cone angle of the height change of the first rear section convex surface is 1.3°;

[0047] The included angle between the outer side and the inner side of the first triangular curved surface is 9.6°, and the included angle between the outer side and the inner side of the second triangular curved surface is 10°.

[0048] Optionally, the special-shaped cabin body also includes a special-shaped cabin body II, which is formed by fusing a front end and a rear end, the front end includes a main profile in an "Ω" shape, the rear end includes a cylindrical surface, the main profile includes a plurality of groups of convex surfaces and a plurality of groups of concave surfaces with negative curvatures, the plurality of groups of convex surfaces and the plurality of groups of concave surfaces are respectively symmetrically arranged, the plurality of groups of convex surfaces include convex surfaces with positive curvatures, rounded surfaces and trapezoidal surfaces, one end of the positive curvature surface is fused to the trapezoidal surface, the other end of the positive curvature surface is fused to the concave surface, and one end of the trapezoidal surface is fused to the concave surface through the rounded surface.

[0049] Optionally, the step of analyzing the special-shaped cabin body formed by fusing convex and concave surfaces of different structural forms to obtain the laying trajectory of the special-shaped cabin body surface specifically includes:

[0050] Analyze the three-dimensional model structure of the special-shaped cabin with convex and concave surfaces of different structural forms;

[0051] Performing meshing processing according to the three-dimensional model structure to extract solid surfaces;

[0052] Based on ABAQUS mesh surface trajectory planning and CATIA spiral line-surface intersection method, trajectory generation is performed on the solid surface to obtain a simulated laying trajectory;

[0053] Based on VERICUT analysis, during the vertical and horizontal wrapping processes of the special-shaped cabin, the simulated wrapping trajectory is subjected to wrapping simulation and interference collision optimization to obtain the wrapping trajectory of the special-shaped cabin curved surface.

[0054] Optionally, the eight-axis and seven-axis linkage automatic laying and wrapping equipment includes a double-column vertical CNC eight-axis control seven-axis linkage laying and wrapping integrated molding equipment, and the double-column vertical CNC eight-axis control seven-axis linkage laying and wrapping integrated molding equipment specifically includes:

[0055] The laying and wrapping part includes a laying and wrapping head and a laying and wrapping wrist, and the end of the laying and wrapping wrist is connected to the laying and wrapping head; the laying and wrapping head includes a pressing roller device, a prepreg tape heating device, a tape tension control system, a tape cutting device, a creel and a deviation correction device in sequence along the laying direction, and is used to realize the laying and forming of reciprocating cycles of overlapping amounts of different proportions and the laying and forming of various complex skin structures with special-shaped curved surfaces;

[0056] The equipment host comprises a linear drive unit and a rotary drive unit, both of which are connected to the laying and wrapping head, the linear drive unit comprises an X linear axis, a Y linear axis and a Z linear axis in sequence, which are respectively used to realize left and right movement, front and back extension and vertical lifting of the laying and wrapping head, and the rotary drive unit comprises an A rotary axis, a B rotary axis and a C rotary axis, which are respectively used to realize the pitch, roll and yaw of the laying and wrapping head;

[0057] A rotary worktable is arranged below the laying and wrapping part, and comprises a workpiece rotating axis C1, which is used to realize the spatial motion interpolation and workpiece rotation of the laying and wrapping head during the forming stage of the special-shaped cabin.

[0058] Optionally, the eight-axis and seven-axis linkage automatic laying and wrapping equipment includes a gantry-type horizontal laying and wrapping equipment, and the gantry-type horizontal laying and wrapping equipment specifically includes:

[0059] Gantry stand;

[0060] A slide box group, wherein the slides are arranged at the left and right ends of the gantry frame and are rotatably connected to the gantry frame, and the slide box group includes a left slide box and a right slide box;

[0061] A laying and wrapping head, the laying and wrapping head is arranged on the slide box group, the laying and wrapping head comprises a laying and wrapping head, the wrapping head is arranged on the side of the left slide box, the laying and wrapping head is connected to the left slide box through an X rotation axis, a Y rotation axis, a Z rotation axis, an A rotation axis, a B rotation axis and a C rotation axis respectively, so as to realize the complex movement of the wrapping head in space;

[0062] The tape laying head is arranged at the lower end of the right slide box, and the tape laying head is connected to the right slide box through a three-axis swing arm.

[0063] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0064] An embodiment of the present application provides a special-shaped cabin with a high lift-to-drag ratio aerodynamic appearance. By analyzing the special-shaped cabin with a fusion of convex and concave surfaces, a laying trajectory is obtained, and then the obtained laying trajectory is laid with eight-axis and seven-axis linkage automatic laying equipment under RTCP control conditions. It can ensure that the resin prepreg and the cloth tape in the laying process can be fully wrapped and adhered to the surface of the cabin, thereby avoiding the low quality problem of the manually formed cabin and further improving the laying quality of the special-shaped cabin. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0066] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0067] Figure 1 A schematic diagram of a process for a method provided in an embodiment of the present application;

[0068] Figure 2 A detailed flow chart of the method provided in the embodiment of the present application;

[0069] Figure 3 This is a schematic diagram of an orthographic projection of a special-shaped cabin I provided in an embodiment of the present application;

[0070] Figure 4 A schematic side projection diagram of a special-shaped cabin 1 provided in an embodiment of the present application;

[0071] Figure 5 An overall schematic diagram of the near-net-shape automatic placement process provided in an embodiment of the present application;

[0072] Figure 6A schematic diagram of laying out the skin of a special-shaped cabin 1 provided in an embodiment of the present application;

[0073] Figure 7 A schematic diagram of the relationship between the curvature of the track on the plane and the strain of the prepreg tape provided in an embodiment of the present application;

[0074] Figure 8 A schematic diagram of deformation of the prepreg tape during curved placement provided in an embodiment of the present application;

[0075] Fig. 9 A schematic diagram of the curvature of a curve on a free-form surface provided in an embodiment of the present application;

[0076] Fig.10 A schematic diagram of the effect of cutting and feeding the yarn bundle provided in an embodiment of the present application;

[0077] Fig.11 A schematic diagram of the software design planning process provided for an embodiment of the present application;

[0078] Fig.12 Provide a flowchart for reconstructing the topological relationship of the INP file for the embodiment of the present application;

[0079] Fig.13 A schematic diagram of the relationship between points, edges, and faces of the INP file provided in the embodiment of the present application;

[0080] Fig.14 A schematic diagram of generating a reference path using the line-surface intersection method provided in an embodiment of the present application;

[0081] Fig.15 A schematic diagram of an example of generating a path curve using the line-surface intersection method provided in an embodiment of the present application;

[0082] Fig.16 A schematic diagram of the structure of the laying equipment provided in the embodiment of the present application;

[0083] Fig.17 A schematic diagram of analysis parameters of microelement ABCD provided in an embodiment of the present application;

[0084] Fig.18 A schematic diagram of the reference line effect of a quasi-revolutionary surface provided in an embodiment of the present application;

[0085] Fig.19 A schematic diagram of the reference line effect of an open curved surface provided in an embodiment of the present application;

[0086] Fig. 20 A schematic diagram of the laying and winding trajectory planning and design process provided in an embodiment of the present application;

[0087] Fig.21 A schematic diagram of the functional division of the laying trajectory planning software module provided in an embodiment of the present application;

[0088] Fig. 22 A schematic diagram of the C-axis speed and speed fluctuation curve collected by SSTT provided in an embodiment of the present application;

[0089] Fig.23 A schematic diagram of the result of the speed planning curve fitting error provided in an embodiment of the present application;

[0090] Fig.24 Schematic diagram of simulation of full profile position of the laying and wrapping head in different postures provided in the embodiment of the present application

[0091] Fig.25 A schematic diagram of the structure of the double pressure rollers provided in the embodiment of the present application;

[0092] Fig.26 A schematic diagram of the structure of the automatic deviation correction system provided in an embodiment of the present application;

[0093] Fig. 27 A physical schematic diagram of a non-orthogonal automatic placement head provided in an embodiment of the present application;

[0094] Fig.28 A schematic diagram of the structure of an orthogonal wideband wrapping head provided in an embodiment of the present application;

[0095] Fig.29 A schematic diagram of the automatic laying trajectory of the special-shaped cabin I provided in an embodiment of the present application;

[0096] Fig.30 A schematic diagram showing the influence of the tension output value of the special-shaped cabin body I provided in an embodiment of the present application on the apparent mass of the front cabin body;

[0097] Fig.31 A schematic diagram showing the influence of the tension output value of the special-shaped cabin body I provided in an embodiment of the present application on the apparent mass of the rear cabin body;

[0098] Fig.32 It is a schematic diagram of a structure tree for quality problems of the winding test process for the special-shaped cabin 1 according to an embodiment of the present application;

[0099] Fig.33 A schematic diagram of the skin structure of the special-shaped cabin II provided in an embodiment of the present application;

[0100] Fig.34 A schematic diagram of the automatic laying and wrapping effect of two different twill fabrics provided in an embodiment of the present application after being cyclically laid and wrapped and superimposed;

[0101] Fig.35 A schematic diagram of the automatic laying trajectory of the special-shaped cabin II provided in an embodiment of the present application;

[0102] Fig.36A schematic diagram of a process flow for automatically laying and wrapping the heat protection layer of a special-shaped cabin II provided in an embodiment of the present application;

[0103] Fig.37 A schematic diagram of the reciprocating laying of the heat protection layer of the special-shaped cabin II provided in an embodiment of the present application;

[0104] Fig.38 A schematic diagram of the floating state of the pressure roller of the special-shaped cabin II provided in an embodiment of the present application under the tension condition of 35%;

[0105] Fig.39 A schematic diagram of the effect of laying 18 layers of prepreg for the special-shaped cabin II provided in an embodiment of the present application; DETAILED DESCRIPTION

[0106] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0107] The creative thinking of this application is: since the composite skin structure generally serves thermal and mechanical dual functions, high requirements are placed on the product's room temperature and high temperature performance, and the implementation method is to ensure fiber continuity as much as possible. Therefore, the first principle is that the cloth tape used is a continuous structure in the molding direction, and short fiber structures cannot be used. Therefore, the prepreg tape is required to be a continuous structure; and the second principle after the composite skin is laid and formed is that the outer surface is not processed after automatic laying and forming. The ultimate goal of automatic laying and forming is to ensure that the outer surface contour is less than 0.8mm.

[0108] By adopting the cabin structure and preparation method of the present application, various laying functions such as reciprocating laying, parallel laying, spiral laying, overlapping laying, etc. can be realized from the aspect of process automation, and the laying and molding of the thin-walled skin with convex and concave surfaces and the shape preservation can be realized, thereby ensuring that the width of the laid fiber mesh cloth tape can achieve 40mm to 240mm wide cloth tape for automatic laying and forming, and can also ensure various functions such as cloth tape heating, blowing, temperature measurement and pulling off during the laying process.

[0109] In one embodiment of the present application, Figure 1 As shown, a method for near-net-shape forming of a large-scale convex-concave curved fusion special-shaped cabin with wide-band automatic lay-up is provided, and the method comprises:

[0110] S1. Analyze the special-shaped cabins with convex and concave surfaces of different structural forms, and obtain the laying trajectory of the special-shaped cabin surface;

[0111] S2. The surface is automatically laid and wound in a loop, and then cured to obtain a large convex and concave surface fusion shaped cabin;

[0112] Wherein, the special-shaped cabin includes special-shaped cabin I and special-shaped cabin II;

[0113] The automatic laying and wrapping includes: automatic laying and wrapping near net shape laying by cyclic winding with eight-axis and seven-axis linkage automatic laying and wrapping equipment under RTCP control conditions;

[0114] The automatic laying and winding methods include vertical laying and winding and horizontal laying and winding;

[0115] The raw materials for the automatic laying and winding include resin and cloth tape, and the structure of the cloth tape is plain cloth or variable twill cloth;

[0116] The thickness of the automatically laid resin is 5 mm to 16 mm, and the width of the automatically laid cloth tape is 40 mm to 80 mm.

[0117] In the embodiment of the present application, the positive effect of controlling the automatic laying resin thickness to 5mm to 16mm is that within this thickness range, the resin laying thickness of the special-shaped cabin can be ensured to be within an appropriate range, thereby ensuring the laying quality of the special-shaped cabin; when the thickness value is greater than or less than the endpoint value of this range, it will result in insufficient laying thickness of the special-shaped cabin or unqualified laying, resulting in affected laying quality.

[0118] The positive effect of controlling the width of the automatically laid tape to be 40 mm to 80 mm is to ensure that the tape can be laid and wound onto the special-shaped cabin body within multiple width specifications, thereby ensuring the laying and wrapping effect.

[0119] In some optional embodiments, the resin used for laying and wrapping the special-shaped cabin body I is a semi-ceramic modified phenolic resin WBFC-20, and the cloth tape used for laying and wrapping the special-shaped cabin body I is a B-type quartz fiber; the structure of the cloth tape used for laying and wrapping the special-shaped cabin body I is a large deformation twill cloth in the warp 45° and weft 45° directions;

[0120] The resin used for laying and wrapping the special-shaped cabin II is a modified phenolic resin, and the cloth tape used for laying and wrapping the special-shaped cabin II is a C-type quartz fiber;

[0121] The structure of the fabric tape used for laying and wrapping the special-shaped cabin II is a small-deformation twill fabric in the directions of warp 0° and weft 90°.

[0122] In the embodiments of the present application, the specific resins and tapes used for wrapping two different special-shaped cabins, as well as the structural form of the wrapped tapes, are controlled to adapt to the wrapping of different cabins. For example, for special-shaped cabin I, large deformation twill fabric in the directions of 45° warp and 45° weft is used for wrapping, and for special-shaped cabin II, small deformation twill fabric in the directions of 0° warp and 90° weft is used. This allows the special-shaped cabin to be fully wrapped, avoiding the defects and low quality caused by manual wrapping.

[0123] In some optional embodiments, the semi-ceramic modified phenolic resin WBFC-20 satisfies: Powder particle size distribution: D 50 <5.5μm, resin content: 52±3%, insoluble content: 14±2%, viscosity at 25℃: 350±50mPa*s, gel time at 150℃: 130±20s, free phenol content<10%;

[0124] The quartz fiber content of the B-type quartz fiber is greater than 99%, and the quartz fiber content of the C-type quartz fiber is greater than 99%.

[0125] In the embodiment of the present application, the positive effect of controlling the semi-ceramic modified phenolic resin WBFC-20 is due to the fact that the ceramic phenolic resin is a highly viscous material, and it is not easy to achieve interlayer connection during the automatic laying and wrapping process. Therefore, the laying and wrapping process needs to adopt a heating method to achieve interlayer bonding while avoiding defects such as overhead tape or interlayer splitting, thereby ensuring that the material of the special-shaped cabin I is fully fitted to the substrate and ensuring the laying quality of the special-shaped cabin I.

[0126] The positive effect of controlling the quartz fiber content of type B quartz fiber and type C quartz fiber is that within this content range, the cloth tape can be ensured to fully wrap the special-shaped cabin body, which is more in line with the automatic near-net shape placement process and achieves high-quality placement of the special-shaped cabin body.

[0127] In some optional embodiments, the automatic laying includes: performing automatic laying and near-net-shape laying based on the principles of fiber tape continuity, no cutting after laying, and axial performance priority;

[0128] The near-net-shape automatic laying includes unidirectional cyclic laying and bidirectional cyclic reciprocating laying;

[0129] The one-way cycle laying and wrapping includes vertical laying and wrapping from top to bottom or from bottom to top, and the one-way cycle laying and wrapping also includes horizontal laying and wrapping from small end to large end or from large end to small end;

[0130] The bidirectional circular reciprocating paving and wrapping includes vertical paving and wrapping from top to bottom or from bottom to top, and the bidirectional circular reciprocating paving and wrapping also includes horizontal paving and wrapping from the small end to the large end or from the large end to the small end.

[0131] In the embodiment of the present application, the principle of controlling the automatic placement of the near-net shape and the corresponding laying and wrapping method can ensure that the corresponding materials of the special-shaped cabin I and the special-shaped cabin II can be fully covered on the curved surface of the special-shaped cabin, thereby ensuring the laying quality of the special-shaped cabin.

[0132] In some optional embodiments, such as Figure 3 As shown, the special-shaped cabin body I is composed of a front cabin body and a rear cabin body that are fused together to form a plane-symmetrical special-shaped shell with convex and concave surfaces. The front cabin body and the rear cabin body are both composed of a plurality of groups of convex surfaces with positive curvature and a plurality of groups of concave surfaces with negative curvature that are fused together, wherein the convex surfaces with positive curvature and the concave surfaces with negative curvature are both formed by a plurality of groups of smooth arcs fused together by spline interpolation.

[0133] In the embodiment of the present application, by splitting the curved surface of the special-shaped cabin body 1, it is ensured that the curved surface trajectory of the special-shaped cabin body 1 can be clearly analyzed, thereby ensuring the subsequent laying quality.

[0134] In some optional embodiments, a two-dimensional coordinate system of the special-shaped cabin body 1 is constructed with the center point of the central axis from the highest point to the lowest point of the cross section of the special-shaped cabin body 1 as the origin, and the front section cabin body is divided into a plurality of groups of front section convex curved surfaces and a plurality of groups of front section concave curved surfaces according to the two-dimensional coordinate system of the special-shaped cabin body 1, and the front section convex curved surfaces and the front section concave curved surfaces are symmetrically arranged one by one;

[0135] The front convex surface includes a first front convex surface in quadrant I, a second front convex surface in quadrant II, a third front convex surface in quadrant III, and a fourth front convex surface in quadrant IV; the front concave surface includes a first front concave surface, a second front concave surface, a third front concave surface, and a fourth front concave surface; the first front concave surface is located at the intersection of quadrant I and quadrant II, the second front concave surface is located at the intersection of quadrant II and quadrant III, the third front concave surface is located at the intersection of quadrant III and quadrant IV, and the fourth front concave surface is located at the intersection of quadrant IV and quadrant I;

[0136] The first front section concave curved surface fuses the first front section convex curved surface and the second front section convex curved surface, and the second front section concave curved surface fuses the fourth front section convex curved surface and the first front section convex curved surface;

[0137] The third front section concave curved surface fuses the second front section convex curved surface and the third front section convex curved surface, and the fourth front section concave curved surface fuses the third front section convex curved surface and the fourth front section convex curved surface;

[0138] The curvature change degree of the first front section concave curved surface or the second front section concave curved surface is greater than the curvature change degree of the third front section concave curved surface or the fourth front section concave curved surface;

[0139] The rear section cabin body is divided into a plurality of groups of rear section convex curved surfaces and a plurality of groups of rear section concave curved surfaces according to the cross section of the two-dimensional coordinates, and the rear section convex curved surfaces and the rear section concave curved surfaces are symmetrically arranged one by one;

[0140] The rear convex surface includes a first rear convex surface in quadrant I, a second rear convex surface in quadrant II, a third rear convex surface in quadrant III, and a fourth rear convex surface in quadrant IV; the rear concave surface includes a first rear concave surface, a second rear concave surface, a third rear concave surface, and a fourth rear concave surface; the first rear concave surface is located at the intersection of quadrant I and quadrant II, the second rear concave surface is located at the intersection of quadrant II and quadrant III, the third rear concave surface is located at the intersection of quadrant III and quadrant IV, and the fourth rear concave surface is located at the intersection of quadrant IV and quadrant I;

[0141] The first rear section concave curved surface fuses the first rear section convex curved surface and the second rear section convex curved surface, and the second rear section concave curved surface fuses the fourth rear section convex curved surface and the first rear section convex curved surface;

[0142] The third rear concave surface fuses the second rear convex surface and the third rear convex surface, and the fourth rear concave surface fuses the third rear convex surface and the fourth rear convex surface;

[0143] The curvature change degree of the first rear concave curved surface or the second rear concave curved surface is greater than the curvature change degree of the third rear concave curved surface or the fourth rear concave curved surface;

[0144] A first rounded convex surface is provided between the second rear-segment convex surface and the first rear-segment concave surface, a second rounded convex surface is provided between the second rear-segment convex surface and the third rear-segment concave surface, a third rounded convex surface is provided between the fourth rear-segment convex surface and the second rear-segment concave surface, a fourth rounded convex surface is provided between the fourth rear-segment convex surface and the fourth rear-segment concave surface, the first rounded convex surface and the second rounded convex surface are relatively symmetrically arranged in quadrants I and III, the third rounded convex surface and the fourth rounded convex surface are relatively symmetrically arranged in quadrants II and IV, and the curvature variation degree of the first rounded convex surface or the second rounded convex surface is less than that of the third rounded convex surface or the fourth rounded convex surface;

[0145] The first rear-section convex surface, the second rear-section convex surface, the third rear-section convex surface, the fourth rear-section convex surface, the first rear-section concave surface, the second rear-section concave surface, the third rear-section concave surface, the fourth rear-section concave surface, the first rounded convex surface, the second rounded convex surface, the third rounded convex surface and the fourth rounded convex surface form a large end surface, the second rear-section convex surface forms a first triangular surface together with the first rounded convex surface and the second rounded convex surface in a direction away from the large end surface, and the fourth rear-section convex surface forms a second triangular surface together with the third rounded convex surface and the fourth rounded convex surface in a direction away from the large end surface.

[0146] In the embodiment of the present application, by limiting the curved surfaces of the front section and the rear end of the special-shaped cabin body I, it is convenient to mesh the overall curved surface of the special-shaped cabin body I, and then to extract the curved surface. By controlling the curvature change of different front concave curved surfaces, the data of the front curved surface is further simplified, and the subsequent analysis of the curved surface data is convenient, thereby facilitating the subsequent laying of the special-shaped cabin body I, and ensuring that the cabin body after the subsequent near-net-shape automatic laying has good laying quality.

[0147] In some optional embodiments, the front section cabin body and the rear section cabin body are both in a double cone shape, and the longitudinal projection surface of the front section cabin body includes a set of symmetrical front section symmetric surfaces, and the semi-cone angle of the height change of the front section symmetric surface is 4.2°;

[0148] The longitudinal projection surface of the rear section cabin body includes a group of symmetrical rear section symmetric surfaces, and the semi-cone angle of the height change of the rear section symmetric surfaces is 1.3°;

[0149] The semi-cone angle of the height change of the third front section convex surface is 2.5°, the semi-cone angle of the height change of the first front section convex surface is 5.6°, the semi-cone angle of the height change of the third rear section convex surface is 3°, and the semi-cone angle of the height change of the first rear section convex surface is 1.3°;

[0150] The included angle between the outer side and the inner side of the first triangular curved surface is 9.6°, and the included angle between the outer side and the inner side of the second triangular curved surface is 10°.

[0151] In the embodiment of the present application, by limiting the semi-cone angle of the projection surface of the special-shaped cabin I, and then limiting the semi-cone angles of the convex surface and the concave surface respectively, the height and angle of the special-shaped cabin I can be effectively displayed, thereby facilitating the meshing of the surface of the special-shaped cabin I and ensuring that the cabin has good laying quality after subsequent near-net-shape automatic laying.

[0152] In some optional embodiments, the special-shaped cabin body also includes a special-shaped cabin body II, which is formed by fusing a front end and a rear end, the front end includes a main profile in an "Ω" shape, the rear end includes a cylindrical surface, the main profile includes a plurality of groups of convex surfaces and a plurality of groups of concave surfaces with negative curvatures, the plurality of groups of convex surfaces and the plurality of groups of concave surfaces are respectively arranged relatively symmetrically, the plurality of groups of convex surfaces include convex surfaces with positive curvature, rounded surfaces and trapezoidal surfaces, one end of the positive curvature surface is fused to the trapezoidal surface, the other end of the positive curvature surface is fused to the concave surface, and one end of the trapezoidal surface is fused to the concave surface through the rounded surface.

[0153] In the embodiment of the present application, by limiting the structural features of the cabin II, it is convenient to subsequently perform curved meshing of the special-shaped cabin II, and to facilitate the subsequent near-net-shape automatic placement, thereby ensuring that the cabin after the subsequent near-net-shape automatic placement has good quality.

[0154] In some optional implementations, the step of analyzing the special-shaped cabin body formed by fusing convex and concave surfaces of different structural forms to obtain the laying trajectory of the special-shaped cabin body surface specifically includes:

[0155] S101. Analyze the three-dimensional model structure of the special-shaped cabin with convex and concave surfaces in different structural forms;

[0156] S102. Performing meshing processing according to the three-dimensional model structure to extract solid surfaces;

[0157] S103. Based on ABAQUS mesh surface trajectory planning and CATIA spiral line-surface intersection method, trajectory generation is performed on the solid surface to obtain a simulated laying trajectory;

[0158] S104. Based on VERICUT analysis, during the vertical and horizontal wrapping processes of the special-shaped cabin, wrapping simulation and interference collision optimization are performed on the simulated wrapping trajectory to obtain the wrapping trajectory of the special-shaped cabin curved surface.

[0159] In the embodiment of the present application, by refining the specific steps from the three-dimensional model structure to the laying and wrapping trajectory, it is ensured that the data of the special-shaped cabin can be fully refined, thereby ensuring the accuracy of the laying and wrapping trajectory, and ensuring the smooth progress of the laying and wrapping and the quality of the laying and wrapping.

[0160] In some optional implementations, based on ABAQUS mesh surface trajectory planning and CATIA spiral line and surface intersection method, trajectory generation is performed on the solid surface to obtain a simulated laying trajectory, and based on VERICUT analysis, during the vertical and horizontal laying process of the special-shaped cabin, the simulated laying trajectory is subjected to laying simulation and interference collision optimization to obtain the laying trajectory of the special-shaped cabin surface, specifically including:

[0161] S113. Importing the solid surface into the simulation software to obtain a simulated digital model;

[0162] S123. The simulation model is converted through finite element software to obtain an INP file;

[0163] S133. Import the INP file into the laying winding trajectory generation software to obtain the surface generation trajectory;

[0164] S143. The generated trajectory of the surface is processed by post-processing software to obtain NC code;

[0165] S153. Import the NC code into the machine tool to obtain the laying trajectory of the special-shaped cabin surface.

[0166] In the embodiment of the present application, the simulated graphics of the surface are converted into the data format of specific points, faces and normal vectors through the INP file, and then the digitized surface is reconstructed through the generation software, so as to show the generation path and trajectory of the surface. Finally, the generated trajectory is processed by post-software to obtain the NC code, so as to form a code recognizable by the machine tool, and then obtain sufficient molding data to facilitate the cabin body laying and molding.

[0167] In some optional embodiments, the eight-axis and seven-axis linkage automatic laying and wrapping equipment includes a double-column vertical CNC eight-axis control seven-axis linkage laying and wrapping integrated molding equipment, and the double-column vertical CNC eight-axis control seven-axis linkage laying and wrapping integrated molding equipment specifically includes:

[0168] The laying and wrapping part includes a laying and wrapping head and a laying and wrapping wrist, and the end of the laying and wrapping wrist is connected to the laying and wrapping head; the laying and wrapping head includes a pressing roller device, a prepreg tape heating device, a tape tension control system, a tape cutting device, a creel and a deviation correction device in sequence along the laying direction, and is used to realize the laying and forming of reciprocating cycles of overlapping amounts of different proportions and the laying and forming of various complex skin structures with special-shaped curved surfaces;

[0169] The equipment host comprises a linear drive unit and a rotary drive unit, both of which are connected to the laying and wrapping head, the linear drive unit comprises an X linear axis, a Y linear axis and a Z linear axis in sequence, which are respectively used to realize left and right movement, front and back extension and vertical lifting of the laying and wrapping head, and the rotary drive unit comprises an A rotary axis, a B rotary axis and a C rotary axis, which are respectively used to realize the pitch, roll and yaw of the laying and wrapping head;

[0170] A rotary worktable is arranged below the laying and wrapping part, and comprises a workpiece rotating axis C1, which is used to realize the spatial motion interpolation and workpiece rotation of the laying and wrapping head during the forming stage of the special-shaped cabin.

[0171] In the embodiment of the present application, by limiting the specific structure of the automatic laying and wrapping equipment, the main machine of the equipment is used to bear the linear drive units including the X linear axis, the Y linear axis and the Z linear axis, and the rotary drive units including the A rotary axis, the B rotary axis and the C rotary axis, so as to ensure the spatial movement of the laying and wrapping head, and then by limiting the rotary worktable, it can be ensured that the workpiece and the laying and wrapping head move simultaneously, thereby ensuring the complete laying and wrapping of the workpiece by the laying and wrapping part including the laying and wrapping head and the laying and wrapping wrist, and ensuring the laying and wrapping quality of the special-shaped cabin in the vertical laying and wrapping stage.

[0172] In some optional embodiments, the eight-axis and seven-axis linkage automatic laying and wrapping equipment includes a gantry-type horizontal laying and wrapping equipment, and the gantry-type horizontal laying and wrapping equipment specifically includes:

[0173] Gantry stand;

[0174] A slide box group, wherein the slides are arranged at the left and right ends of the gantry frame and are rotatably connected to the gantry frame, and the slide box group includes a left slide box and a right slide box;

[0175] A laying and wrapping head, the laying and wrapping head is arranged on the slide box group, the laying and wrapping head comprises a laying and wrapping head, the wrapping head is arranged on the side of the left slide box, the laying and wrapping head is connected to the left slide box through an X rotation axis, a Y rotation axis, a Z rotation axis, an A rotation axis, a B rotation axis and a C rotation axis respectively, so as to realize the complex movement of the wrapping head in space;

[0176] The tape laying head is arranged at the lower end of the right slide box, and the tape laying head is connected to the right slide box through a three-axis swing arm.

[0177] In the embodiment of the present application, by introducing a slide box group and a three-axis swing arm, the laying and wrapping head is divided into a laying head and a wrapping head for movement, so that horizontal laying and wrapping of the special-shaped cabin can be performed more flexibly to ensure the laying and wrapping effect.

[0178] In some optional embodiments, the software for generating the laying and winding trajectory specifically includes an STL file topology reconstruction module, a slicing ring generation module, a reference line generation module, a reference trajectory generation module, other trajectory generation modules, a trajectory boundary processing module, a trajectory planning post-processing module and a trajectory simulation module.

[0179] In an embodiment of the present application, by adopting different modular components of the generation software, the STL file topology reconstruction module is used to store the point, edge and face data of the surface, and then the slicing ring generation module is used to generate the initial surface from the data, and distinguish whether the surface data is an open surface or a quasi-revolutionary surface, and then the reference line generation module, the reference trajectory generation module and other trajectory generation modules are used to distinguish different initial surface types, thereby speeding up the efficiency of the algorithm, and finally the trajectory boundary processing module is used to determine and simulate the point information of the starting yarn feeding position and the ending yarn breaking position of the yarn path, and finally the trajectory planning post-processing module is used to use the inverse kinematics solution method to obtain the motion of each axis of the laying machine, and then generate the machine motion code, and finally the trajectory simulation module is used to determine whether the machine motion code can obtain a suitable cabin shape, and then the cabin data can be efficiently converted into machine tool processing data, which facilitates the processing and forming of the cabin.

[0180] Example 1

[0181] Taking the special-shaped cabin I as an example, the special-shaped cabin I is composed of a front cabin and a rear cabin, which are fused together to form a plane-symmetrical special-shaped shell with convex and concave surfaces. The front cabin and the rear cabin are both composed of a plurality of groups of convex surfaces with positive curvature and a plurality of groups of concave surfaces with negative curvature, wherein the convex surfaces with positive curvature and the concave surfaces with negative curvature are both fused together by a plurality of groups of smooth arcs through spline interpolation.

[0182] The positive curvature convex surface and negative curvature concave surface of the shell are formed by the fusion of multiple groups of smooth arcs through spline interpolation to form a symmetrical structure of convex and concave surfaces. The relatively smooth positive curvature ruled surfaces of the quadrants II and IV of the two wings of the rear section of the special-shaped cabin I are respectively formed by the transition fusion of the concave surface of the upper leeward surface and the concave surface of the lower windward surface through two groups of traditional fillet surfaces; the front section of the shell I is formed by the symmetrical fusion of eight groups of convex and concave surfaces, including four groups of positive curvature convex surfaces and four groups of negative curvature concave surfaces. The rear section of the shell I is formed by the fusion of eight groups of positive curvature convex surfaces and four groups of negative curvature concave surfaces in a face-symmetrical structure. The eight groups of convex surfaces include two groups of positive curvature convex surfaces, four groups of fillet surfaces, and two groups of triangular surfaces that are approximately ruled surfaces, specifically:

[0183] like Figure 4 As shown, a two-dimensional coordinate system of the special-shaped cabin body I is constructed with the center point of the central axis from the highest point to the lowest point of the cross section of the special-shaped cabin body I as the origin, and the front section cabin body is divided into multiple groups of front section convex curved surfaces and multiple groups of front section concave curved surfaces according to the two-dimensional coordinate system of the special-shaped cabin body I, and the front section convex curved surfaces and the front section concave curved surfaces are symmetrically arranged one by one;

[0184] The front convex surface includes a first front convex surface in quadrant I, a second front convex surface in quadrant II, a third front convex surface in quadrant III, and a fourth front convex surface in quadrant IV; the front concave surface includes a first front concave surface, a second front concave surface, a third front concave surface, and a fourth front concave surface; the first front concave surface is located at the intersection of quadrant I and quadrant II, the second front concave surface is located at the intersection of quadrant II and quadrant III, the third front concave surface is located at the intersection of quadrant III and quadrant IV, and the fourth front concave surface is located at the intersection of quadrant IV and quadrant I;

[0185] The first front section concave curved surface is fused with the first front section convex curved surface and the second front section convex curved surface, and the second front section concave curved surface is fused with the fourth front section convex curved surface and the first front section convex curved surface;

[0186] The third front section concave curved surface fuses the second front section convex curved surface and the third front section convex curved surface, and the fourth front section concave curved surface fuses the third front section convex curved surface and the fourth front section convex curved surface;

[0187] The curvature change degree of the first front concave surface or the second front concave surface is greater than the curvature change degree of the third front concave surface or the fourth front concave surface;

[0188] The rear section cabin body is divided into a plurality of groups of rear section convex curved surfaces and a plurality of groups of rear section concave curved surfaces according to the cross section of the two-dimensional coordinates, and the rear section convex curved surfaces and the rear section concave curved surfaces are symmetrically arranged one by one;

[0189] The posterior convex surface includes a first posterior convex surface in quadrant I, a second posterior convex surface in quadrant II, a third posterior convex surface in quadrant III, and a fourth posterior convex surface in quadrant IV; the posterior concave surface includes a first posterior concave surface, a second posterior concave surface, a third posterior concave surface, and a fourth posterior concave surface; the first posterior concave surface is located at an intersection of quadrant I and quadrant II, the second posterior concave surface is located at an intersection of quadrant II and quadrant III, the third posterior concave surface is located at an intersection of quadrant III and quadrant IV, and the fourth posterior concave surface is located at an intersection of quadrant IV and quadrant I;

[0190] The first rear concave surface is fused with the first rear convex surface and the second rear convex surface, and the second rear concave surface is fused with the fourth rear convex surface and the first rear convex surface;

[0191] The third rear concave curved surface is fused with the second rear convex curved surface and the third rear convex curved surface, and the fourth rear concave curved surface is fused with the third rear convex curved surface and the fourth rear convex curved surface;

[0192] The curvature change degree of the first rear concave curved surface or the second rear concave curved surface is greater than the curvature change degree of the third rear concave curved surface or the fourth rear concave curved surface;

[0193] A first rounded convex surface is provided between the second rear-segment convex surface and the first rear-segment concave surface, a second rounded convex surface is provided between the second rear-segment convex surface and the third rear-segment concave surface, a third rounded convex surface is provided between the fourth rear-segment convex surface and the second rear-segment concave surface, a fourth rounded convex surface is provided between the fourth rear-segment convex surface and the fourth rear-segment concave surface, the first rounded convex surface and the second rounded convex surface are relatively symmetrically arranged in quadrants I and III, the third rounded convex surface and the fourth rounded convex surface are relatively symmetrically arranged in quadrants II and IV, and the curvature variation degree of the first rounded convex surface or the second rounded convex surface is less than that of the third rounded convex surface or the fourth rounded convex surface;

[0194] The first rear section convex surface, the second rear section convex surface, the third rear section convex surface, the fourth rear section convex surface, the first rear section concave surface, the second rear section concave surface, the third rear section concave surface, the fourth rear section concave surface, the first rounded convex surface, the second rounded convex surface, the third rounded convex surface and the fourth rounded convex surface form a large end surface, the second rear section convex surface forms a first triangular surface with the first rounded convex surface and the second rounded convex surface in a direction away from the large end surface, and the fourth rear section convex surface forms a second triangular surface with the third rounded convex surface and the fourth rounded convex surface in a direction away from the large end surface.

[0195] Among them, the height of the front section cabin is 800mm, the length and width of the small end of the front section are 983.3mm*548.3mm respectively, and the length and width of the large end of the front section are 1099.9mm*665.9mm respectively; the rear end of the front section of the cabin has the same outline as the front end of the rear section, and the length and width of the interface fusion section are 1099.9mm*665.9mm;

[0196] The height of the rear section cabin is 1225mm, the length and width of the small end of the rear section are 1099.9mm*665.9mm, and the length and width of the large end of the rear section are 1159.6mm*735.3mm.

[0197] The maximum dimensions of the special-shaped cabin I are 2025mm*1159.6mm*735.3mm.

[0198] The front cabin and the rear cabin are both in a double cone shape. The longitudinal projection surface of the front cabin includes a set of symmetrical front symmetry surfaces. The semi-cone angle of the height change of the front symmetry surface is 4.2°.

[0199] The longitudinal projection surface of the rear section cabin body includes a set of symmetrical rear section symmetry surfaces, and the semi-cone angle of the height change of the rear section symmetry surface is 1.3°;

[0200] The semi-cone angle of the height change of the convex surface of the third front section is 2.5°, the semi-cone angle of the height change of the convex surface of the first front section is 5.6°, the semi-cone angle of the height change of the convex surface of the third rear section is 3°, and the semi-cone angle of the height change of the convex surface of the first rear section is 1.3°;

[0201] The included angle between the outer side and the inner side of the first triangular curved surface is 9.6°, and the included angle between the outer side and the inner side of the second triangular curved surface is 10°.

[0202] The analysis of the special-shaped taper structure characteristics of the special-shaped cabin I is as follows:

[0203] Under the premise of this tapered structure, parallel overlapping winding from the small end to the large end is achievable, but it is difficult to achieve the width of the cloth tape and its overlapping amount for each cabin body by parallel overlapping winding at one time, and it is very difficult to achieve it in one time without the need for external surface processing; if parallel reciprocating winding is adopted, the width of the cloth tape and its corresponding overlapping amount are also critical. Therefore, in the case of the deformation of the cloth tape, bidirectional reciprocating flat winding is preferred. As long as the interlayer strength is sufficient, the influence of the seam can be minimized. In addition, it can be inferred from the performance of the sample after burning in the early stage that parallel reciprocating winding is better than parallel overlapping winding. Therefore, this application mainly uses parallel reciprocating winding molding, and overlapping winding molding is an alternative. The three principles followed by the specific molding method are as follows:

[0204] (1) Principle of fiber tape continuity: The ceramic heat-resistant layer has near-zero ablation, takes away little heat, and has a large high-temperature thermal conductivity, which will inevitably lead to a sharp temperature rise in the surface layer and cause great thermal stress. The heat-resistant layer has both thermal and mechanical functions. High requirements are placed on the strength of the composite material, especially the thermal strength. The implementation method is to ensure the continuity of the fiber as much as possible. In principle, the tape used is required to be a continuous structure in the molding direction, and short fiber structures cannot be used. Therefore, the prepreg tape is required to be a continuous structure.

[0205] (2) Principle of no cutting after laying and winding: It can be seen from the observation of the flat-wound sample after the high-temperature test that the resin has evaporated completely; from the cross-section observation of its axial structure, it can be seen that only a short section is left after the external cutting. This kind of fiber will definitely be vulnerable to high temperature and high-speed erosion; its advantage is that it is continuous in the circumferential direction, but the axial fiber length is too short to support the circumferential continuous fiber to form an overall effect; if it is a diagonal winding structure, the fiber is a short fiber structure in the axial and circumferential directions, and its overall strength will be weaker in theory. Therefore, another principle for this non-ablative composite thermal protection layer is to minimize or no processing. The goal of automatic laying molding is to require the contour of the outer surface to be less than 0.5, and it is acceptable to be no more than 0.8, that is, the contour requirement is between 0.1 and 0.8.

[0206] (3) Principle of axial performance priority: Through mechanical performance testing, it can be seen that the conditions of samples with different structures are similar at room temperature (resin and fiber work together). After exceeding 300°C, the resin slowly melts, and after approaching 450°C, a sharp change occurs. The overall trend is that the high-temperature performance is ranked as follows: overall flat laying (the cloth tape is too wide to be automated) > parallel reciprocating winding (the wider the cloth tape, the better) > parallel overlapping winding (cutting processing is required and there is serious waste) > twill cloth slanting (short fibers fall apart at high temperatures) > overall molding. It is expected that the overall strength of the circumferential direction will be improved through this research, but it is still uncertain whether the axial direction will be disengaged (overall circumferential cracks) under a pneumatic heating environment; therefore, it is required to achieve enhanced axial tensile performance through process design.

[0207] (4) Automation requirements: From the perspective of process automation: reciprocating winding > parallel overlapping winding > overall tiling. The current equipment function cannot achieve overall tiling and can only be operated manually.

[0208] Although parallel overlapping winding from the small end to the large end can be achieved, it is difficult to achieve the width of the cloth tape and the overlap amount of each cabin body in parallel overlapping winding at one time, and it is very difficult to achieve it in one time without the need for external surface processing; if parallel reciprocating winding is used, the width of the cloth tape and its corresponding overlap amount are also critical; in the case of no deformation allowance, reciprocating flat winding is preferably bidirectional, as long as the interlayer strength is sufficient, the impact of the seam can be minimized. In addition, through the preliminary detection of the performance of the sample after burning, it can be inferred that parallel reciprocating winding is better than parallel overlapping winding. Therefore, this test mainly selects parallel reciprocating winding molding, and overlapping winding molding is an alternative.

[0209] The overall solution process of near-net-shape automatic placement is as follows: Figure 5 As shown, the structure of a part of the special-shaped cabin I is selected, such as Figure 6As shown, the automatic laying thickness of the automatic parallel reciprocating winding molding is 8mm to 16mm. The raw material used is vitrified phenolic resin. Due to the high viscosity of vitrified phenolic resin, it is not easy to achieve interlayer connection during the automatic laying process of the tape. Heating is required during the laying process to achieve interlayer bonding while avoiding defects such as tape overhead or interlayer splitting. The vitrified phenolic resin used is semi-ceramic modified phenolic resin WBFC-20 to meet the good ablation resistance of the heat protection layer surface when it is washed by high-temperature particles. The prepreg is black due to the porcelain powder. Among them, the main technical indicators of WBFC-20 are as follows: Powder particle size distribution: D (50) <5.5μm;Resin content: 52±3%;Insoluble matter content: 14±2%;Viscosity (25℃): 350±50mPa*s;Gel time (150℃): 130±20s;Free phenol content: <10%;The fabric tape used in the special-shaped cabin I is C-type quartz fiber, the quartz fiber content of which is greater than 95%, the fabric width is 40mm / 60mm / 80mm, and the fabric tape structure adopts two types of plain fabric and deformable twill fabric, wherein the deformable twill fabric tape includes: the laying form is that the warp and weft are both 45° direction and can be greatly deformed twill fabric, the surface is black porcelain modified phenolic quartz fiber material, and near net shape automatic laying is adopted;

[0210] like Fig. 9 As shown, the laying form is a small deformation twill fabric with a warp of 0° and a weft of 90°, the surface is a yellow phenolic resin quartz fiber cloth tape, and near-net shape automatic laying is adopted;

[0211] The laying form is a twill fabric with large deformation in which both the warp and weft yarns are in the 45° direction, and the laying form is a twill fabric with small deformation in which the warp yarns are 0° and the weft yarns are 90°. The two structures are automatically laid after cyclic laying and superposition.

[0212] The preparation method of the special-shaped cabin body I comprises:

[0213] S1. Obtain a three-dimensional model of the special-shaped cabin;

[0214] S2. Perform meshing processing according to the three-dimensional model to extract the surface;

[0215] S31. Importing the surface into the simulation software to obtain a simulated digital model;

[0216] S32. The simulation model is converted through finite element software to obtain an INP file;

[0217] S33. Import the INP file into the laying winding trajectory generation software to obtain the surface generation trajectory;

[0218] S41. The generated trajectory of the surface is processed by post-processing software to obtain NC code;

[0219] S42. Import the NC code into the machine tool to obtain the setting parameters of the surface.

[0220] S5. Automatically lay out the cabin according to the set parameters to obtain a high-quality special-shaped cabin;

[0221] The curved surface includes a convex curved surface and a concave curved surface, and the automatic placement is performed by overlapping placement in a parallel reciprocating winding manner.

[0222] Automatic laying also includes laying along the ground line;

[0223] Automatic placement also includes placing in a manner that a center track in the placement track is reserved with a margin spacing;

[0224] Automatic placement is a seven-axis placement controlled by RTCP function.

[0225] The laying and winding trajectory generation software specifically includes an STL file topology reconstruction module, a slicing ring generation module, a reference line generation module, a reference trajectory generation module, other trajectory generation modules, a trajectory boundary processing module, a trajectory planning post-processing module and a trajectory simulation module.

[0226] 1. The problems and solutions faced by the above method in the design stage are: the first is the acceleration and deceleration problem at the rounded corners on both sides, the second is the mold pasting problem of the two negative curvature concave surfaces on the leeward side, and the third is the cloth width and its equal overlap under the conditions of the overall shape surface characteristics.

[0227] For the first problem, the R fillet at the acute angle is offset by an appropriate distance for laying and winding, considering that the elastic pressure roller behind can keep up with the beat at the turning point; the second problem is mainly about the following rhythm of the pressure roller; the third problem requires the surface to be fitted with straight lines, and the length of the straight lines is solved under the premise of fitting accuracy <0.5 or <1, ​​so as to obtain the optimal cloth width. Since the overlap affects the axial tensile performance, the inability to keep up with the axial performance may cause the circumferential fibers to fall apart and be resistant to scouring, so it is necessary to choose carefully.

[0228] (1) Parallel reciprocating winding: To avoid air scouring, the last layer of winding is required to be carried out from the large end to the small end to form a structure that follows the airflow; the reciprocating laying design is: automatic laying is carried out from top to bottom once, then automatic laying is carried out from bottom to top once, and then a manual layer is laid to improve the axial performance. Subsequently, the laying is repeated until the thickness meets the design value, and the manual layer is cancelled when the final thickness is laid.

[0229] (2) Overlapping design: Overlapping is carried out from the small end to the large end. The width of the tape is temporarily selected as 40 mm, and the feed rate is 5 mm / r.

[0230] (3) According to the above requirements, the specific test parameters are designed as follows:

[0231] ① Reciprocating laying of 60mm wide alkali-free prepreg cloth: alkali-free prepreg cloth, the tape width is 60mm, and the feed rate is 30mm / r.

[0232] ② Reciprocating laying of 40mm wide alkali-free prepreg cloth: alkali-free prepreg cloth, the tape width is 40mm, and the feed rate is 20mm / r.

[0233] ③ Overlapping laying of 40mm wide alkali-free prepreg: Alkali-free prepreg, overlapping laying is carried out from the small end to the large end, the tape width is 40mm, and the feed rate is 5mm / r.

[0234] ④ Reciprocating laying of 40mm wide mesh prepreg: mesh prepreg, the tape width is 40mm, and the feed rate is 20mm / r.

[0235] ⑤ Reciprocating laying of 60mm wide mesh prepreg: mesh prepreg, the tape width is 60mm, and the feed rate is 30mm / r.

[0236] (4) Near-net-shape automatic laying test Automatic laying test objectives:

[0237] 1) 40mm wide pitch parallel reciprocating winding conventional cloth belt pass;

[0238] 2) 40mm wide and small step parallel overlapping winding to verify the feasibility;

[0239] 3) Use the verified laying process parameters and the formal fabric tape to lay the test piece, and conduct performance sampling, testing and comparison;

[0240] 4) Based on the results in 3), determine the process equipment program reliability, process program optimization, RTCP application, programming and process automation and efficiency.

[0241] 2. Verification of the near-net-shape forming of wideband automatic lay-up for large convex and concave curved shaped cabin I:

[0242] 1. Design principle:

[0243] According to the working mode and technical characteristics of automatic placement, the placement trajectory must meet certain design requirements, mainly including the following aspects: directionality requirements, layability requirements, full coverage requirements and economic requirements, etc.

[0244] (1) Directional requirements:

[0245] In order to facilitate the layup design of components according to the structural strength requirements, the commonly used trajectory design method is the fixed angle method, that is, the trajectory line always forms a fixed angle with the reference line. Common layup angles are 0°, ±45° and 90°. This method is simple and practical. For most component trajectories, it can meet the process characteristics of tape laying. However, it does not fully consider other requirements of trajectory design, such as the requirements for the paveability and economy of the trajectory.

[0246] (2) Requirements for layability:

[0247] The layability of the trajectory is the ability to ensure that the prepreg does not deform (wrinkle, tear) during the laying process. The deformation range of prepreg is very small. When laying on complex curved surfaces, it can only be done along a specific trajectory, otherwise it will cause wrinkles or tears, which will affect the laying quality of the component. When automatically planning the laying trajectory of complex curved surface components, the algorithm must comprehensively consider the deformation factors of the prepreg during the laying process based on the curved surface shape of the component. Since the elastic modulus of the reinforcing fibers in the prepreg is very high, the longitudinal tensile deformation capacity of the fibers is limited during the laying process, and the micro-buckling caused by the longitudinal compression of the fibers is the main mechanism of deformation of the prepreg tape.

[0248] Take plane laying as an example, Figure 7 As shown in the figure, if the laying track is a straight line, the edge lengths of each track of the prepreg with a limited width are the same, and no wrinkles will be generated. If the laying track is a curve, the prepreg tape will deform due to the different arc lengths of the tracks corresponding to each fiber: the outermost fiber of the prepreg tape ( Figure 7 The fiber at point O in the middle is subjected to tensile stress, but due to the rigidity constraint, the deformation is very small and can be regarded as zero, while the fibers in other parts need to produce compression / micro-buckling deformation to form Figure 7 When the macroscopic compression deformation exceeds a certain extreme value, macroscopic wrinkles (such as Figure 8 ). Figure 7 and Figure 8 The model adopts the beam bending theory, and the outermost side of the arc is taken as the neutral layer. The strain value at point b is the largest, which is taken as the control value of the deformation of the prepreg tape:

[0249]

[0250] Where w is the bandwidth and R is the radius of curvature of the laying track.

[0251] Formula (1) shows that when the width w of the prepreg tape used is constant, the larger the curvature radius R of the laying track on the plane, that is, the smaller the curvature of the track, the smaller the absolute value of the fiber strain, and the better the layability of the track.

[0252] Since most of the actual laid-up surfaces are curved surfaces, the free-form surface is used as the object to study the characteristics of any curve on it. C is a curve on the surface, P is an arbitrary point on the curve, k is the curvature vector of the curve at point P, t is the unit tangent vector, and n is the unit normal vector of the surface at point P. According to differential geometry theory, the curvature vector k of any point on the curve can be decomposed into two parts: one in the direction of the surface normal n, and the other in the u direction perpendicular to n and the tangent vector t of the curve at that point, that is:

[0253] k=k n *n+k g *u (2)

[0254] Where kn is the normal curvature of the curve, kg is the geodesic curvature;

[0255] kn is the curvature related to the surface itself, which will only cause the prepreg tape to produce longitudinal bending deformation in the thickness direction. Since the prepreg is very thin (generally 0.125mm~0.2mm), it will not affect the layability of the track. The existence of geodesic curvature kg will cause the prepreg tape to produce lateral bending deformation and thus affect the layability. In the limited neighborhood of point P, the deformation of the prepreg tape can be calculated by its projection deformation on the tangent plane, and the projection curvature of the curve on the tangent plane is its geodesic curvature. Therefore, for the laying track of any free-form surface, the size of its geodesic curvature can be used as the basis for judging the layability of the track line.

[0256] According to differential geometry, the geodesic curvature on the geodesic line between two points on the surface is zero everywhere. Therefore, it can be concluded that the laying quality of components obtained by laying tapes along the geodesic direction of the surface is the most ideal. Based on this, a method of laying along the geodesic trajectory is proposed.

[0257] (3) Full coverage requirements

[0258] The full coverage requirement means that when laying a single layer, the wide tape meets the requirements of the gap tolerance design, so that the wide tape can be fully covered without overlapping. In the process of automatic tape laying, due to the complexity of the component surface, the laying trajectory obtained by a certain algorithm does not necessarily ensure that the distance between the center lines of the trajectory remains constant. The spacing may be too small or too large. If not properly handled, it will cause partial overlap or vacancies of the wide tape (such as Fig.10 As shown, different cutting of the yarn bundles will lead to different arrangements before and after the cutting operation of the yarn bundles, causing inconsistent layer thickness, thereby reducing the manufacturing accuracy of the component and ultimately affecting the performance of the component.

[0259] Under the action of compaction force, the bandwidth of prepreg usually changes slightly. In order to more accurately control the gap between prepreg tapes or wide cloth tapes, a certain margin of spacing should be reserved between the center tracks when planning the track.

[0260] (4) Economic requirements

[0261] On the basis of meeting the above requirements, the trajectory should save materials, reduce costs and improve efficiency as much as possible. The main measures are: a. Incorporate boundary preprocessing into trajectory design to realize the automation of boundary cutting. Boundary processing technology is the key to meeting component forming requirements, reducing manufacturing costs, and realizing continuous laying from simple single layer to complex layer groups to improve production efficiency.

[0262] b. Consider the variable angle trajectory design method based on stress distribution for components under complex stress conditions to further reduce weight and save costs. However, the actual stress distribution state of the laminate ply is related to the stiffness distribution, and the consistency between the principal stress direction and the ply fiber direction is uncertain. Integrating component stress distribution, ply design and trajectory planning can better play the advantages of variable angle trajectory design.

[0263] 3. Algorithm for Automatic Trajectory Formation

[0264] 1. Laying trajectory design and post-processing analysis

[0265] (1) Software design and usage process:

[0266] Open the digital model used in CATIA, adjust the digital model to the appropriate position, and save it; then use ABAQUS finite element software to convert the digital model in CATIA into an INP file; then import the generated INP file into the laying trajectory generation software, complete the topology between the triangular facets in the INP file and the laying trajectory planning in the software, and finally convert the generated laying trajectory points into NC codes that can be recognized by the machine tool through the post-processing software. The general planning process is as follows: Fig.11 As shown,

[0267] (2) Software design mechanism analysis:

[0268] In order to further realize the data processing of the trajectory, the software algorithm analysis is used to realize the analysis and processing of the trajectory. The core algorithm idea is:

[0269] (I) Trajectory planning based on meshed surfaces:

[0270] Based on the mesh surface trajectory planning, the surface mesh is discretized to apply the finite element idea to trajectory planning. The solution domain is regarded as composed of many interconnected subdomains. A suitable approximate solution is assumed for each unit, and then the total satisfaction conditions of the domain are derived to obtain the solution of the problem. This method not only has high calculation accuracy under the premise of ensuring the mesh division accuracy, but also can adapt to various complex shapes. In general, the mesh surface trajectory planning has the following advantages:

[0271] (a) It has a wide range of applications and is not limited by the type of surface;

[0272] (b) The problem of finding a curved trajectory on a free-form surface can be transformed into the problem of finding a straight trajectory on a tiny plane, greatly simplifying the difficulty of trajectory realization;

[0273] (c) Another feature of gridded surface trajectory planning is that the trajectory planning has a large degree of freedom. It can complete analyzable trajectories or trajectory lines that are difficult to achieve with existing CAD software, such as near geodesics and trajectory lines based on component stress distribution, according to certain special requirements of the process or component structure.

[0274] However, surface meshing will generate a large amount of discrete data. In order to carry out trajectory planning more effectively, these data need to be sorted out beforehand.

[0275] (II) Introduction to INP files:

[0276] The INP file (extension .inp) is a text file that contains a complete description of the entire model and establishes a bridge for data transmission between the preprocessor (such as ABAQUS / CAE) and the solver (ABAQUS / Standard or ABAQUS / Explicit). Because the INP file format is simple, easy to read and display, it has been widely used in rapid prototyping, graphic reality display, finite element analysis and reverse engineering, and has become a de facto industrial standard. At present, the INP file format has been widely used in various CAD platforms, and many mainstream commercial CAD software platforms support the input and output of INP files. Compared with other data files, the main advantages of this type of file are simple data format and good cross-platform performance, and various types of spatial surfaces can be output. The INP file consists of the definition of multiple triangular patches, and the definition of each triangular patch includes the three-dimensional coordinates of each vertex of the triangle and the normal vector of the triangular patch. The order of arrangement of the triangle vertices follows the right-hand rule. This file format is similar to the meshing of the finite element, that is, the surface of the object is divided into many small triangles, and many triangular patches are used to approximate the CAD solid model. It describes a spatially closed, bounded, regular model that uniquely expresses an object. It contains geometric information of points, lines, and surfaces and can fully express the surface information of the entity.

[0277] (III) INP file topology reconstruction:

[0278] After a CAD model is generated into an INP file, the number of its triangular meshes is tens of thousands or even hundreds of thousands. Since the INP model only records the geometric information of the surface of the object, and does not have any topological information that expresses the relationship between geometric bodies, if a triangle is taken from the INP file, the trajectory points are directly obtained in the INP file according to various conditions to obtain the entire trajectory line. The calculation workload may take several hours or even dozens of hours. At the same time, the data redundancy of the INP format file is very large, and each vertex is stored repeatedly about six times or more. Therefore, it is a very critical step to reconstruct the topological information of the INP file based on the position information, which is conducive to removing data redundancy and improving data relevance.

[0279] This software reconstructs the topology of INP files and divides the data structure into three categories: point, edge, and facet. In order to achieve rapid generation of trajectories, the reconstructed data must meet the following requirements:

[0280] (1) Given a triangle, its three edges, three vertices and normal vector can be obtained;

[0281] (2) If an edge is known, its two endpoints and the faces on both sides of the edge can be known;

[0282] (3) A known point can obtain the coordinate value of the point and all edges and faces intersecting the vertex.

[0283] In order to save space and time for storing topological relationships, a face only records the numbers of its three vertices and three edges and the face normal vector. An edge only records the numbers of its two end points and the numbers of the two side patches. A point records its coordinate values ​​and the numbers of all edges and patches that intersect the point. The specific data structure is as follows:

[0284] (1) Data structure of the face:

[0285] int Facet Index; / / facet index number

[0286] int Point Index[3]; / / Three vertex index numbers

[0287] int Edge Index[3]; / / three edge index numbers

[0288] double Normal[3]; / / face normal vector

[0289] (2) Edge data structure:

[0290] int Edge Index; / / edge index

[0291] int Point Index[2]; / / index of both end points

[0292] int Facet Index[2]; / / Index of the two side panels

[0293] (3) Data structure of points:

[0294] int Point Index; / / point index

[0295] double Point[3]; / / Point coordinates

[0296] int Edge Index

[24] ; / / Index of all edges intersecting this vertex

[0297] int Facet Index

[24] ; / / Index numbers of all faces intersecting this vertex

[0298] Since the number of edges or facets that intersect a vertex is uncertain (usually about 6), a sufficiently large array should be created to store them, and the excess part of the array should be filled with "0". After the INP file is exported and stored in the database, the database language can be used directly to reconstruct the topological relationship of the data. Three data tables for points, edges, and faces are pre-established. The reconstruction algorithm flow chart is as follows: Fig.12 The specific sorting process is as follows:

[0299] 1) Read in a triangular face and assign the normal vector to Normal[3] in the face table;

[0300] 2) Take a vertex of the triangle and check whether there is a point with the same coordinates in the point table. If so,

[0301] The index number of the point with the same coordinates is assigned to the Point Index in the face table; if it does not exist, the vertex is stored in the point table, and the index number of the point in the point table is assigned to the Point Index in the face table;

[0302] 3) If all three vertices of the face have been traversed, proceed to the next step, otherwise proceed to step 2);

[0303] 4) According to the vertex index number of the face, three edges are constructed. In order to avoid duplication of edges due to the reversal of the end point numbers, the end point numbers are arranged from small to large.

[0304] 5) Read an edge of a triangular face, and determine whether there is an identical edge in the edge table based on the numbers of its two endpoints. If not, assign the index numbers of its two endpoints and the face number to Point Index and FacetIndex[0] in the edge table, respectively, and assign the index number of the edge in the edge table to Edge Index in the face table. If it exists, it indicates that the edge has been stored before, and you only need to update Facet Index[1] in the edge table to the current face number, and assign the index number of the edge with the same endpoints to Edge Index in the face table.

[0305] 6) If all three edges of the triangle are traversed, proceed to the next step, otherwise proceed to step 5);

[0306] 7) If all triangles have been traversed, proceed to the next step, otherwise proceed to step 1);

[0307] 8) Add all edges and faces that intersect the vertex. Read a vertex number, find the index numbers of all edges and faces that have the vertex number in the PointIndex in the edge table and face table, and assign them to the Edge Index and FacetIndex in the point table;

[0308] 9) If all vertices have been traversed, then it is complete, otherwise execute 8).

[0309] by Fig.13 Taking the INP file of as an example, the results obtained by applying the above topology reconstruction algorithm are shown in Tables 1, 2 and 3. The coordinate values ​​in Table 1 correspond to the x, y, and z values ​​of the vertex, and the type is floating point; the "all edges intersecting the vertex" column represents the index numbers of all edges intersecting the corresponding vertex. The detailed information of the edge can be found in Table 2 through the index number of the edge; the "all faces intersecting the vertex" column records the index numbers of all faces intersecting the corresponding vertex. The detailed information of the face can be found in Table 3 through the index number of the face. Table 2 only lists the information of the first 12 edges. The "two end point index numbers" correspond to the vertex index numbers in Table 1, and the "two side patch index numbers" correspond to the patch index numbers in Table 3. For the edges on the boundary, only the patch number on one side of the edge is recorded, and the other side is assigned to "0". In this way, it is convenient to judge whether the trajectory has reached the model boundary when planning the trajectory. Table 3 records all the vertex index numbers and edge index numbers of the corresponding patches, and the normal vector also corresponds to three floating point values.

[0310] Table 1 Vertex topology

[0311]

[0312]

[0313] Table 2 Edge topology (only the first 12 items are listed)

[0314]

[0315] Table 3 Topological structure of the surface

[0316]

[0317] (III) Core algorithm idea:

[0318] Helix surface intersection trajectory algorithm based on small-pitch helix and surface-symmetric rotation structure:

[0319] For closed surface components such as fuselage, S-shaped air inlet, etc., if the axial direction is the 0° tape laying direction and the perpendicular direction is the 90° tape laying direction, the cross-section method can also be used to generate the tape laying path at the above two angles. However, for the 45° or other inclined angles between the two, due to the particularity of the rotary structure, the cutting plane method is no longer applicable. For this reason, for this type of component, the line-surface intersection method is proposed to generate the path trajectory curve under the inclined angle. The principle is to first create a straight line and an equidistant spiral line (fixed curve) on the inside and outside of the surface respectively, and then connect the corresponding points of the two into a straight line. Then this straight line must intersect with the surface to obtain an intersection point (the straight line and the surface here are "line" and "surface"), and the intersection points are distributed on the surface in a spiral shape around the axis. Obviously, this cannot be done by the cutting plane method.

[0320] Suppose the equidistant spiral line with the axis of the core mold as the center line is S(t), the spiral angle is determined by the inclination angle, and the radius should be selected to ensure that the line connecting the center line intersects the surface. Suppose the center line of the parameterized core mold is D(t), and the points on the spiral line and the core mold axis are connected into a line. Then, as the value of parameter t changes within the definition domain, the intersection trajectory of the connecting line and the surface is a curve, which is set as P(t) as the reference path curve, as follows Fig.14 shown.

[0321] Therefore, a vector relationship can be established between the three curves:

[0322] S(t)-P(t))×(S(t)–D(t)=0 (4)

[0323] Assume E(t) = S(t) – D(t), take the derivative of the above equation and substitute it into equation (4), multiply Pu and Pv on both sides of the equation respectively, and solve it according to the vector algebraic relationship: (A×B)·C=A·(B×C), and we get:

[0324]

[0325] In which, let M(t) = S'(t) × E(t) + [S(t) – P(t)] × E'(t). Similarly, given any starting point P0 on the intersection line, substitute its initial value:

[0326]

[0327] After iterative calculation, a continuous curve can be obtained on the core mold surface as the tape laying path, such as Fig.15 As shown,

[0328] From the above examples, it can be seen that the line-surface intersection method solves the problem of generating the tape laying path for rotary components at an inclined angle, and the inclination angle is applicable to any value between (0°, 90°). At the same time, it can be found that the line-surface intersection method is very practical, and a certain path trajectory can be generated for both convex and concave curved components.

[0329] It should also be noted that if the core mold axis D(t) is a straight line, S(t) is an equidistant spiral line with D(t) as the center line and a fixed spiral angle (such as 45°), and for cylindrical surfaces (such as spindle-shaped fuselages, etc.), the direction of the tangent vector at any point on the path curve obtained after the line and surface intersect is not strictly speaking equal to the spiral angle everywhere. In most cases, there is a slight error, which is determined by the shape of the non-cylindrical surface. However, for most large structural parts, the change in structural performance caused by this slight deviation is negligible, so it is acceptable. In addition, it can be seen from the algorithm that, under the condition of ensuring that the line intersects with the surface after connection, the radius of the spiral line has no effect on the angle and shape of the generated curve.

[0330] After trajectory planning is completed, the accuracy of the curve needs to be further improved. In places where the curvature of the mold surface changes greatly, this can be solved by increasing the number of trajectory points.

[0331] 4. Post-processing technology of automatic laying and winding post-processing technology:

[0332] Laying equipment structure Fig.16 As shown, it includes X, Y, Z, A, B, C axes and the main axis, a total of seven motion axes (3 translation axes and 4 rotation axes). When choosing the laying principle, the laying principle should be selected according to production needs so that it can meet the laying requirements. If the prepreg resin system is sensitive to the laying speed and the prepreg needs to be heated during the laying process, the constant laying speed principle needs to be applied to ensure the laying quality; if large components are formed and the core mold has a large moment of inertia, the constant core mold speed principle needs to be applied to ensure that the drive motor can meet the spindle motion characteristics.

[0333] Since the infrared lampshade will interfere with the mold surface during the laying process, the prepreg will not be heated during the laying process. According to previous experiments, the laying effect of prepreg at room temperature is acceptable, and the laying speed requirement is not high. The core mold size is large, and theoretically the principle of constant spindle speed should be adopted as the basis for post-processing. However, due to the irregular shape of the surface, interference between the mold and the laying head arm is easy to occur when laying negative curvature surfaces. Therefore, during post-processing, the laying point should be kept as far away from the arm as possible, that is, the A-axis axis should be kept in a horizontal position as much as possible.

[0334] (1) Track laying process verification:

[0335] Prepreg tapes or prepreg yarns are generally composed of unidirectional reinforcing fibers and a resin matrix. Under ideal laying conditions, the fibers in the prepreg tapes or prepreg yarns are strain-free at all locations. However, in reality, the resin matrix restricts the fibers to a certain position range, and the elastic modulus of the fibers is relatively large. Therefore, the deformation capacity of the prepreg tapes or prepreg yarns is limited during the laying process and they cannot be laid along any path.

[0336] If a non-geodesic trajectory such as a fixed angle or variable curvature is used, it is generally achieved through the in-plane deformation of the prepreg wide tape. Assuming that the center line of the prepreg wide tape in the width direction is the placement trajectory curve, n and μ correspond to the thickness direction and width direction of the prepreg tape / yarn respectively. Since the width of the prepreg tape / yarn is greater than the thickness, according to the beam bending theory of material mechanics, the same curvature will cause greater strain and distortion in the width direction. Therefore, the geodesic curvature of the prepreg yarn / tape should be focused on and studied.

[0337] Select a microelement ABCD along the prepreg tape or prepreg yarn, such as Fig.17 As shown, the study is conducted. The width of the prepreg tape or prepreg yarn is w. When selecting, ensure that its edges AB and CD are perpendicular to the fibers. The extension lines on both sides of the microelement intersect at point C, and the angle between them is dα. Since the microelement is small in size, the surface on which the microelement is located can be approximated as its tangent plane, and the problem can be transformed from the surface to its unfolded surface; if the influence of the normal curvature of the prepreg tape or prepreg yarn is ignored, the deformed fibers in the microelement are regarded as arcs, the curvatures in the arcs AD and BC do not change, and the centers of the circles are the same point, as shown in Fig.15 As shown in the figure, in order to make the planned trajectory line reflect the deformation of the whole prepreg tape / yarn intuitively, the center line of the prepreg tape or prepreg yarn is used as the placement trajectory line for planning, and its geodesic curvature in the microelement is set to be k g , geodesic radius R = 1 / k g ,but:

[0338]

[0339] It can be seen that |AD|>|BC|.

[0340] If the fiber in the microelement ABCD does not deform in the AD segment, the fiber on one side (the BC segment side) is compressed, the fiber tends to be structurally unstable and release stress through buckling deformation, the prepreg will buckle, and the ratio of the shortening of the BC segment before and after the stress release under the compressive stress to its original length is defined as strain ε, and the AD segment length is considered to be equivalent to the length of the BC segment before buckling, and the following formula is obtained:

[0341]

[0342] If the fiber in the microelement ABCD does not deform in the BC segment, the fiber on one side (the AD segment side) is stretched, and the prepreg tends to slip and flip to release stress. The ratio of the elongation of the AD segment before and after stress release under tensile stress to its original length is defined as strain ε, and the length of the BC segment is considered to be equivalent to the length of the AD segment before buckling, and the following formula is obtained:

[0343]

[0344] The above failure behaviors will affect the mechanical properties of the cured products to varying degrees. It can be seen that when the geodesic curvature k g When =0, the prepreg yarn has no deformation.

[0345] And k g The larger the value, the larger ε. When the strain reaches the critical value and the microscopic failure increases to a certain extent, the prepreg tape or prepreg yarn will fail at the macroscopic side, affecting the laying quality. In summary, the laying processability of the track mainly depends on the geodesic curvature k of the track. g , the geodesic curvature can be used as a basis for judging the paving suitability of the trajectory line.

[0346] The 89° and 45° trajectories are planned at a fixed angle. The laying effect diagram shows that the higher the laying angle, the greater the geodesic curvature of the trajectory. Therefore, there are serious wrinkles in the 89° ply, which affects the laying of subsequent layers and also forms gaps at the wrinkles, wide tape overlaps and other defects, seriously affecting the performance of the component.

[0347] As large-angle trajectories account for a large proportion in the layup, in order to ensure the quality of the components, the pre-laying angles were adjusted to a certain extent, reducing the 89° trajectory to an 80° trajectory and increasing the 45° trajectory to a 60° trajectory. Under the condition that there is no significant impact on the final component performance, the angle of the circumferential layup layer is reduced as much as possible to improve the layup quality. After the modification, the layup quality of the corresponding position of the layup is improved.

[0348] (2) Determination of post-processing principles:

[0349] Since the curvature of the product laid by the wrapping machine varies greatly, the path and interference problems are more prominent. The interference problems were solved through repeated verification:

[0350] 1) Horizontal normal vector principle: always keep the normal vector of the placement point in the horizontal plane. During placement, interference between the mold and the C-axis arm and gear is likely to occur, affecting the smooth progress of placement.

[0351] 2) Principle of equal height of laying points: always make the height of laying points the same as the axis. During laying, interference between the mold and the C-axis swing arm, gear, and Z-axis balance cylinder is likely to occur, affecting the smooth progress of laying.

[0352] 3) Principle of composite selection: The normal vector directions of the placement points on the left and right sides of the mold symmetry plane are deflected up and down by a certain angle respectively, and fluctuations are allowed within a certain range, ultimately solving the interference and collision problems.

[0353] (3) Automatic tape laying trajectory planning software module:

[0354] When designing the software, in order to avoid the impact of different surface types and different planning algorithms on the versatility of the software, the software was divided into six major modules: 1) STL file topology reconstruction module, 2) slice ring generation module, 3) reference line generation module, 4) reference trajectory generation module, 5) other trajectory generation module, 6) trajectory boundary processing module, 7) trajectory planning post-processing module, and 8) trajectory simulation module.

[0355] 1) STL file topology reconstruction module:

[0356] In order to extract surface information, the surface is meshed using STL files, the laid surface is meshed and discretized, and the surface problem is transformed into a plane using the plane approximation method, which can reduce the planning difficulty and improve efficiency. However, its data format only contains the normal vectors and vertex coordinates of the triangular facets, and does not contain the topological relationship between the vertices. Therefore, the same data point is often stored repeatedly, which increases the redundancy of the file data. When performing trajectory planning in discrete triangular facets, each time the trajectory point is obtained, it is necessary to query the facet information of the common points or edges. If the query is repeated in a large number of data points each time, it will face a huge amount of calculation. Moreover, as the amount of data increases, the amount of calculation will increase exponentially. Therefore, it is imperative to improve data relevance and establish the topological information of the triangular facets in the STL file.

[0357] According to the characteristics of meshed surfaces and trajectory planning algorithms, the topological relationship should include point, edge, and surface data structures: a. Point data structure: point index number, point coordinates, edge index number of common points, and surface index number of common points; b. Edge data structure: edge index number, point index number (2), and surface index number of common edges (2); c. Surface data structure: surface index number, vertex index number (3), edge index number (3), and surface normal vector; Due to the particularity of trajectory planning for open-hole surfaces, the prepreg yarn must undergo a process of cutting or re-feeding at the opening. In order to facilitate the determination of cutting and feeding points, the properties of edges and surfaces must be quickly distinguished: whether the edge is a model boundary or a hole boundary, and whether the surface is inside or outside the hole, a boundary identifier should be added to the edge data structure, and inside and outside hole identifiers should be added to the surface data structure.

[0358] 2) Slice ring generation module:

[0359] The purpose of generating a slice ring is to facilitate the acquisition of other trajectory points. The generation rule depends on the surface structure type. If it is a quasi-revolution surface, the slice ring is a set of annular curves on the surface, such as Fig.18 As shown; if it is an open surface, the slice ring is a set of non-closed curves on the surface, such as Fig.19 shown.

[0360] 3) Reference trajectory generation module:

[0361] Generate a reference trajectory according to the selected algorithm. Common reference trajectory algorithms include fixed-angle trajectory planning algorithm, geodesic trajectory planning algorithm and variable-angle trajectory planning algorithm.

[0362] 4) Other trajectory generation modules:

[0363] The generation rules of the trajectory points of other trajectories offset on the reference line according to the reference trajectory depend on the surface structure type. If it is a quasi-revolution surface, the other trajectories are obtained by the equal arc length method. The algorithm has small calculation amount, high planning efficiency, and can avoid excessive and concentrated yarn break points; if it is an open surface, the other trajectories are obtained by the parallel equidistant method. The algorithm is simple and applicable, and easy to develop software.

[0364] 5) Track boundary processing module:

[0365] The trajectory boundary processing makes the planned trajectory further reflect the surface shape. The specific processing is as follows: the trajectory that does not intersect the model boundary is extended by extrapolation. The extension direction is determined by the two trajectory points closest to the boundary, and the starting yarn feeding position and the ending yarn breaking position of each yarn path are determined according to the boundary shape characteristics. If the surface contains an opening, the trajectory of each yarn path should also be traversed to obtain the intersection of the trajectory and the hole boundary, and the corresponding yarn feeding and breaking position should be marked.

[0366] 6) Trajectory planning post-processing module:

[0367] According to the information of trajectory points, the inverse kinematics solution method is applied to obtain the motion of each axis of the automatic tape laying machine and generate the machine motion code.

[0368] (4) Automatic placement programming simulation implementation process:

[0369] The trajectory is virtualized to determine the deformation state of the pre-impregnated wide tape, and the machine state during the machine movement is simulated, and obstacle avoidance analysis is performed. The trajectory design system is an integrated design and manufacturing software system that integrates trajectory design, trajectory optimization, post-processing, trajectory simulation and other functions. It provides different trajectory design schemes for different workpiece configurations, optimizes trajectories based on the complexity of components and laying efficiency, implements post-processing algorithms based on the redundant seven-axis machine tool architecture, and provides trajectory simulation analysis function modules to facilitate trajectory design and verification. According to the working mode and technical characteristics of automatic placement, the laying trajectory must meet certain design requirements, mainly including the following aspects: directional requirements, layability requirements, full coverage requirements and economic requirements.

[0370] Fig.36 For the laying trajectory planning design process, when designing the laying trajectory planning software based on the trajectory planning design process, in order to avoid the influence of different surface types and different planning algorithms on the versatility of the software, the software is divided into six modules for writing: 1) STL file topology reconstruction module, 2) reference line generation module, 3) reference trajectory generation module, 4) other trajectory generation module, 5) trajectory boundary processing module, 6) trajectory planning post-processing module, 7) trajectory simulation module, Fig.21 It is composed of functional modules of automatic tape laying trajectory planning software.

[0371] (5) Automatic placement software design and implementation:

[0372] It is compiled based on VC6.0 and has a good human-computer interface. Each module has detailed parameter input options, and each module can export corresponding generated data.

[0373] First, at the "start" execution stage of the program, you need to enter the "parameter setting" stage, including "process parameters", "prepreg tape parameters", "core mold geometry parameters" and "mechanical parameters". OpenGL will use this data to build the core mold geometry model, complete the layer planning, layer trajectory planning and prepreg tape cutting planning. After the overall planning is completed, the trajectory generated by the discretization algorithm will be obtained to obtain the "geometric information" and "cutting information" of the control points.

[0374] By "data separation" of the above information, two types of data can be obtained: one is the cutting control point data, which is used to simulate the boundary or process cutting situation; the solution of the cutting control code will verify the validity of this part of the cutting data, and if an error occurs, an error report will be sent to control the number of wide cloth tapes, the laying length and the final shape. The other type is point data that will be used for "axis transformation" and "solving the inverse kinematic problem". If the laying mechanism interference phenomenon is detected, an error report will pop up and return to the hierarchical trajectory planning stage to re-plan the laying trajectory; in addition, this part of the data will be used in three-dimensional simulation, and "data merging" with the cutting data will be performed to complete the laying process control together. The NC code generated by post-processing can be used for three-dimensional dynamic simulation and can also be used for the conversion of the tape laying machine NC code to complete the actual laying.

[0375] (I) Six-axis or seven-axis RTCP near-net compliant placement control technology based on redundant degrees of freedom:

[0376] 1. Optimization of laying trajectory and RTCP control of special-shaped cabin.

[0377] (1) Advantages of automatic wrapping RTCP control:

[0378] The first vertical eight-axis controlled seven-axis linkage automatic winding forming equipment in China adopts the CNC system of Huazhong CNC HNC848. The system has multi-axis linkage control functions, such as Fig. 22 As shown in the figure, after experimental verification, the numerical control system is stable and reliable. There are significant differences in the laying trajectory, product laying quality and efficiency between RTCP control and non-RTCP control.

[0379] When non-RTCP control is used for laying, the main problems are low laying efficiency and unstable trajectory speed; when laying passes through the edges of the workpiece, the laying speed slows down significantly, resulting in low laying efficiency; the speed in other areas of the laid workpiece is unstable, and the speed of the concave surface is greater than that of the convex surface, resulting in large changes in the machine tool speed.

[0380] When the RTCP winding is not in progress, the speed is unstable during the winding process. When the speed is increased, some linkage axes will vibrate, especially the C axis of the rotary table. Fig. 22 Another aspect is that the laying process is characterized by additive processing. The floating stroke of the pressure roller cylinder is limited. After the material is laid to a certain thickness, it is necessary to modify the tool length similar to the five-axis machine tool cutting and then regenerate the laying process. The operation is more troublesome. The main reason is that the machine tool structure is not considered when calculating the arc length of the trajectory. The multi-axis small line segment fitting is in multi-dimensional space. The speed planning is disturbed by incorrect curve fitting results, such as Fig.23 shown.

[0381] When the RTCP function is used for seven-axis winding linkage control, the kinematic structure parameters of the machine tool are taken into account when performing the kinematic solution calculation inside the system. The control principle of the RTCP function is to perform spline fitting and speed planning in the workpiece coordinate system, so that the machine tool movement is smoother without frequent acceleration and deceleration. Fig.24 As shown in the figure, there will be no jitter during acceleration and deceleration. When performing wide-band spiral laying, the smoothness of each motion axis is improved, thereby making the winding effect more efficient. When the feed rate is 2000, the time taken for laying one circle of RTCP is approximately 1min8s; the non-RTCP time is approximately 1min50s. At the same time, RTCP can perform tool length compensation to solve the problem of thickness compensation and thus improve programming efficiency.

[0382] (2) Improvement measures for the design of the laying and wrapping system:

[0383] The main and auxiliary pressure rollers are designed and improved according to the status determined by debugging. The hardware improvements mainly include the segmented design of pressure rollers, optimization of hook leg spacing, optimization of lifting separation film, optimization of main and auxiliary pressure roller pressure combination, etc. At the same time, it is planned to adopt double-belt laying head design and verification to further improve efficiency without reducing the pre-pressing time of prepreg cloth.

[0384] In terms of CNC system, the multi-axis linkage RTCP control function is improved in the laying trajectory control program to eliminate the "pulse" problem in the laying process and achieve the continuity and smoothness of the laying trajectory. In terms of automatic laying CNC program, it is necessary to further optimize the program points to achieve better simulation effect and further improve efficiency. At the same time, it is necessary to further study the laying program and design dynamic adaptive adjustment of parameters such as tension output value and laying speed at different circumferential positions to reasonably control the laying quality at different positions.

[0385] (V) Non-orthogonal placement head of large-scale placement equipment mainframe and core functional components:

[0386] The CNC double-column tape laying machine has a seven-axis linkage function, which can realize the laying / taping of most of the special-shaped composite shell products currently under development. The first automatic laying and forming process test was carried out using this CNC double-column tape laying machine. The automatic laying test was carried out on a metal shell of a convex and concave curved shaped cabin. The automatic laying process was explored using different cloth widths and different feed rates. During the exploration process, the program trajectory optimization, CNC system matching, laying output tension, hot air temperature, film winding method, laying parameter design optimization and other aspects were comprehensively verified, and finally the automatic laying and forming of a convex and concave curved shaped cabin heat protection layer test piece was realized.

[0387] The main CNC double-column vertical laying equipment can achieve the laying of special-shaped curved skin with a maximum laying envelope diameter of Φ2500 and a maximum height of 3500mm, a maximum laying speed of 30m / min, a laying angle deviation of ±0.5°, a laying belt gap accuracy of ±2.5mm, a laying belt thickness deviation of ±0.5mm, an adjustable laying belt tension of 5N~200N, a main roller pressure of more than 500N, an auxiliary roller pressure of more than 500N, an adjustable hot air temperature of up to 150℃, an automatic correction function accuracy of ±1mm, and a travel of ±10mm. The maximum rotation diameter of the C axis of the worktable is Φ2000mm, the speed is 0~10r / min, and the acceleration is 70° / s 2 , the radial travel of the arm on the X axis is 1000mm, the servo feed speed is 18000mm / min, and the acceleration is 1000mm / s 2 , arm lateral movement stroke Y axis stroke 2000mm, servo feed speed 30m / min, acceleration 1000mm / s 2 , beam vertical travel Z axis 3500mm, servo feed speed 8000mm / min, acceleration 1m / s 2 , the A-axis rotation stroke of the winding head is ±90°, the servo feed speed is 20000mm / min, and the acceleration is 70° / s 2 , winding head pitch B axis travel ±30°, servo feed speed 10000mm / min, acceleration 70° / s 2 , winding head yaw C1 stroke axis ±70°, servo feed speed 10000mm / min, acceleration 70° / s 2 , U-axis speed of the winding head is 20000mm / min, acceleration is 70° / s 2 .

[0388] (1) Large-scale double-column vertical CNC eight-axis controlled seven-axis linkage wrapping integrated forming equipment, which consists of the equipment host, wrapping head, wrapping wrist, rotary table, core mold rotation system and machine tool control system. The wrapping head includes a pressure roller device, a prepreg heating device, a cloth tension control system, a cloth cutting device, a yarn rack and a deviation correction device. The equipment host adopts a double-column vertical structure, and uses three linear axes XYZ to drive the up and down Z axis, the front and rear telescopic Y axis, and the left and right moving X axis of the laying head. The three rotary axes ABC drive the pitch A axis, roll B axis, and yaw C axis of the laying head. The rotating table drives the workpiece rotation C1 axis to realize the spatial motion interpolation and workpiece rotation of the wrapping head. It adopts the domestic Huazhong HNC848 high-end CNC system to realize eight-axis control and seven-axis linkage laying; the composite skin structure is formed by fitting various special-shaped curved surfaces in space with ruled surfaces of different widths in space; the equipment has adjustable laying output tension, adjustable hot air temperature, and automatic film winding and automatic laying forming functions. It has 40-120mm wide fabric tapes that can be laid in a reciprocating cycle, parallel overlapping, oblique winding, spiral winding, etc. to achieve reciprocating laying and forming with different overlapping proportions to achieve the laying and forming of various complex skin structures with special-shaped curved surfaces.

[0389] Laying and wrapping head: The laying and wrapping head is the most important and critical component of the tape laying and wrapping machine. It is the executive component in the automatic tape laying and forming process. It mainly realizes the functions of cutting, conveying, clamping, compacting, tension control, and heating of the prepreg tape.

[0390] Laying and wrapping wrist: The laying and wrapping wrist is one of the main components of the laying and wrapping machine. It is mainly used to connect and install the laying and wrapping head (sometimes also including the yarn box) and realize various required movements of the laying and wrapping head. It usually refers to the assembly mechanism of each axis except the movement of the workpiece.

[0391] Yarn box (material roll): The yarn box is a device that holds the prepreg tape and distributes and guides the wide tape path and controls the tension of the prepreg tape.

[0392] Wrapping angle: the angle between the cloth tape wrapped around the core mold and the axis of the core mold.

[0393] Laying line type: the shape of the laying tape on the core mold, the laying line type includes arc, straight line, etc.

[0394] Winding accuracy: The front and rear prepreg tapes are continuously wound onto the mold, and the size of the gap between them is an indicator of winding accuracy.

[0395] Prepreg tape width and thickness: The width of the prepreg tape is generally 75mm, 150mm, 300mm, 600mm and other specifications. There are also 100mm, 200mm and other specifications in China. The thickness is generally 0.1-0.25mm.

[0396] Laying speed: The length of tape that can be laid onto the mold per unit time, representing the productivity and efficiency of laying the tape.

[0397] Equipment host and functional components and control system, the overall equipment such as Fig.16 As shown, including Fig.25 The double rollers shown and Fig.26 The automatic correction system shown.

[0398] (2) Core functional components of non-orthogonal automatic tape laying head:

[0399] Large-scale gantry composite tape laying and wrapping forming equipment can realize high-order surface tape laying on more than 7 axes in space during forming processing. The matching A, B, and C swing heads must adapt to the control requirements and be able to realize rotation and swing. The key technology of A, B, and C swing heads mainly studies the influence of axis error on the spatial coordinate transformation of 7-axis linkage control, and finally determines the reasonable processing error. Fig. 27 shown.

[0400] a) Tape laying head: The tape laying head is installed at the lower end of the right slide box. It has the functions of swinging and rotating the three axes A, B, and C, and can complete the laying of wide carbon fiber tapes on complex curved surfaces. In order to meet the requirements of high-speed laying, the A axis of the tape laying head is driven and controlled by dual servo motors, which has good rotation accuracy.

[0401] b) Tape winding head: The tape laying head is installed on the left slide of the gantry tape laying machine. It can realize the movement of X, Y, Z, A, B, and C axes to complete the tape laying requirements of complex spatial surfaces.

[0402] c) Three-axis swing arm of the tape laying head: The A, B, and C three-axis swing angle heads are mainly composed of a connecting plate, a motor seat, an A-axis seat and an interface. When working, the swing angle head is connected to the main machine slide by screws, and the C-axis is driven by the servo motor after being slowed down by a reducer, driving the swing arm head body to rotate ±180°. The A-axis is driven by a backlash-free synchronous belt after being slowed down by a servo motor, driving the tape laying head body and the tape laying head to swing ±40°.

[0403] (3) Functional composition of eight-axis seven-link automatic winding equipment:

[0404] On the basis of the main machine moving in XYZ directions, the workpiece is placed on a rotating worktable. The three linear axes of the main machine, the rotating axis of the worktable, and the pitch / yaw / roll three rotary axes of the wrapping head, a total of seven axes are linked to achieve the laying of special-shaped curved surface skins. All laying and forming are carried out by servo motors. The wrapping head system is an integrated system, which includes functional modules such as a pressure device, a heating device, a tension control system, a film collection device, a detection system, and an anti-collision alarm device. Each module works together to achieve high-quality wrapping of special material rolls on complex workpieces. Fig. 27The automatic tape laying and wrapping head shown can realize two forming processes: automatic laying and automatic winding of the anti-insulation layer of a large-scale special-shaped rotating body.

[0405] During the automatic laying process, the insulation tape is laid with low tension. The laying tension requires that the insulation tape is taut and not loose, and can be deformed appropriately to achieve "follow-shaped placement", especially when laying on the concave surface of the component. Excessive laying tension will cause bridging defects on the concave surface. During the automatic winding process, the winding tension of the prepreg tape is large and the control accuracy is high. Especially at the edge with a small radius of curvature, the winding tension of the insulation tape needs to make the insulation prepreg tape close to the edge.

[0406] The laying and wrapping head has the functions of automatic control of large-scale laying and wrapping tension, automatic deviation correction of prepreg tape, automatic control of hot air heating temperature and automatic winding of prepreg tape, and a double pressure roller system with adjustable laying and wrapping pressure. In addition, the laying and wrapping head is also equipped with a video monitoring system and a molding process parameter acquisition system. Each part realizes the following functions:

[0407] 1) Automatic wrapping tension control system: The wrapping tension control system can realize automatic wrapping tension control in a wide range, with a minimum of 5N and a maximum of 200N. In order to take into account the wrapping tension adjustment range and the control accuracy required by the wrapping forming process, the wrapping head divides the system wrapping tension into two sections: a large tension section of 50N to 200N and a small tension section I of 5 to 50N. The large tension section is mainly used for automatic winding forming, and the small tension section is mainly used for automatic laying forming.

[0408] 2) Hot air heating system: By heating the prepreg tape and the area to be wrapped, the viscosity of the prepreg tape is increased. The hot air heating method has the advantage of uniform heating. The wrapping head uses compressed air as the air source of the air heater, and the heated air is sprayed to the area to be heated through the flute. The maximum outlet temperature of the air heater can reach 400°C. The heating temperature can be set according to the process requirements and closed-loop controlled by the outlet temperature sensor. This system can be operated manually or automatically.

[0409] 3) Double-roller pressing system: The wrapping head adopts a double-roller pressing system to improve the adhesion of the prepreg tape. The main roller and auxiliary roller are both flexible rollers made of rubber to improve the adaptability of complex surfaces. The main roller can move along the linear guide rail and adopts 4 The cylinder provides roller pressure. When the air supply pressure is 0.6MPa, the roller pressure can reach 1200N. The auxiliary roller can swing around the main roller axis. The cylinder provides roller pressure. When the air supply pressure is 0.6MPa, the cylinder thrust can reach 600N. The roller pressure normal to the mold surface changes with the swing angle of the auxiliary roller. The swing stroke of the auxiliary roller can meet the minimum curvature radius of the concave surface R250mm and the minimum curvature radius of the convex surface R15mm, meeting the appearance curvature of the target product. Fig.25 shown.

[0410] 4) Automatic deviation correction system: During the process of laying and winding, due to the influence of factors such as the oblique deformation of the tape, the installation error of the guide roller, the fluctuation of the tape speed and tension, the prepreg tape will deviate laterally, that is, the deviation phenomenon. The deviation of the prepreg tape will affect the performance of the molded parts. Therefore, the automatic deviation correction system is one of the keys to laying and winding. The laying and winding head adopts the deviation correction method during the traveling process, such as Fig.26 As shown in the figure, the deviation correction during the process is to control the deflection angle of two parallel guide rollers in the prepreg conveying path according to the feedback of the position detector to realize the control of the prepreg laying and winding position. The infrared deviation correction sensor is used to detect the position deviation of the prepreg edge and feedback is given to the automatic deviation correction controller for closed-loop control.

[0411] 5) Automatic film-winding system: In addition to the prepreg used for component molding, the prepreg roll also contains a PE film for isolating the prepreg. The function of the automatic film-winding system is to automatically rewind the back film of the prepreg into a roll during the laying and winding process. The system uses a torque motor to drive the film-winding air shaft, and performs open-loop control of the film-winding tension through the laying and winding speed and the film-winding speed. The relationship between the driving current and the driving torque of the torque motor needs to be calibrated in advance. The system can achieve a winding speed higher than the laying speed, and a winding tension lower than the laying tension; it has both automatic and manual control modes.

[0412] 6) Video monitoring and process parameter acquisition system: A camera is installed on the laying head to shoot the laying area. The operator observes the quality and on-site status of the laying area through the monitor on the operating table, and stores the laying process video, thus realizing a closed-circuit television system for quality and safety control. In addition, the laying head is equipped with temperature and pressure sensors to record the laying forming temperature, pressure, ambient temperature, humidity and other process parameters, which is convenient for the traceability of the product quality system.

[0413] (4) Large-scale horizontal laying equipment and its orthogonal wide-band laying head and horizontal laying simulation:

[0414] like Fig.28As shown, the tape laying head is installed on the left slide of the gantry tape laying machine, which can realize the movement of X, Y, Z, A, B, and C axes to complete the laying requirements of complex spatial surfaces. Through the three linear axes X, Y, and Z of the gantry, the three rotary axes A, B, and C of the tape laying head, and the workpiece rotary axis A1 axis, a total of seven axes, the seven-axis linkage near-net laying of 30mm-120mm wide tapes with complex spatial surfaces, wide-band twill fabrics or straight and plain fabrics can be realized. The A, B, and C three-axis swing head is mainly composed of a connecting plate, a motor seat, an A-axis seat, and an interface. When working, the swing head is connected to the main machine slide by screws. The C axis is driven by a servo motor after being decelerated by a reducer, driving the swing arm head body to rotate ±180°. The A axis is driven by a non-gap synchronous belt after being decelerated by a servo motor, driving the tape laying head body and the tape laying head to achieve horizontal laying and laying with a ±90° swing. The specific laying trajectory is shown as follows Fig.29 shown.

[0415] 4. Test verification of the automatic laying and wrapping process of special-shaped cabin I:

[0416] Through the automatic placement molding process test, the equipment function, CNC matching, program fitting, feasibility of automatic placement of prepreg, automatic placement process design and other aspects are explored and verified, laying the foundation for the production and application of subsequent model products. The automatic placement process test is based on a cabin with a special-shaped cabin I-cone front section structure and a special-shaped cabin I-two cone rear section structure. Through the exploration of the placement process of this test piece, the feasibility of automatic placement of the special-shaped cabin I-cone front section structure and the special-shaped cabin I-two cone rear section structure is realized, so as to promote the application to the automatic placement molding of the three-cone section structure, and then realize the automatic placement molding of a certain special-shaped model full-structure product.

[0417] Automatic laying trajectory design and programming: 3D model (product 3D model) → surface extraction → meshing (UG, SYSPLY, CATIE, etc.) → data reconstruction → trajectory generation (AFP&ATL-Software1.0) → post-processing (CAM software) → automatic laying (automatic laying equipment). According to the above process, multiple rounds of automatic laying molding process tests are carried out during the debugging period to continuously optimize materials, processes, procedures, etc.

[0418] (I) Automatic placement molding process parameters

[0419] The test objectives of automatic placement include the following aspects: ① 40mm wide step-width parallel reciprocating winding conventional cloth belt pass;

[0420] ②40mm wide and small step parallel overlapping winding to verify the feasibility;

[0421] ③ Use the verified laying process parameters and formal fabric tape to lay the test piece, and conduct performance sampling, testing and comparison;

[0422] ④ Based on the results of the third step, solve problems such as process equipment program reliability, process program optimization, RTCP application, programming and process automation and efficiency.

[0423] According to the above requirements, the specific test parameters are designed as follows:

[0424] ① Reciprocating laying of 60mm wide alkali-free prepreg cloth: alkali-free prepreg cloth, the tape width is 60mm, and the feed rate is 30mm / r.

[0425] ② Reciprocating laying of 40mm wide alkali-free prepreg cloth: alkali-free prepreg cloth, the tape width is 40mm, and the feed rate is 20mm / r.

[0426] ③ Overlapping laying of 40mm wide alkali-free prepreg: Alkali-free prepreg, overlapping laying is carried out from the small end to the large end, the tape width is 40mm, and the feed rate is 5mm / r.

[0427] ④ Reciprocating laying of 40mm wide mesh prepreg: mesh prepreg, the tape width is 40mm, and the feed rate is 20mm / r.

[0428] ⑤ Reciprocating laying of 60mm wide mesh prepreg: mesh prepreg, the tape width is 60mm, and the feed rate is 30mm / r.

[0429] Automatic placement test objectives:

[0430] ①40mm wide pitch parallel reciprocating winding conventional cloth belt pass;

[0431] ②40mm wide and small step parallel overlapping winding to verify the feasibility;

[0432] ③ Use the verified laying process parameters and formal fabric tape to lay the test piece, and conduct performance sampling, testing and comparison;

[0433] ④ Based on the results of the third step, solve the problems of process equipment program reliability, process program optimization, RTCP application, programming and process automation and efficiency;

[0434] ⑤ Lay out wind tunnel products, thermal joint experimental cabin, and formal flight cabin.

[0435] There are three problems expected in the process of laying and winding: the first is the acceleration and deceleration problem at the rounded corners on both sides, the second is the problem of pasting the two negative curvature concave surfaces on the leeward side, and the third is the cloth width and equal overlap under the condition of the overall appearance surface characteristics. The first problem is to offset the R fillet at the sharp angle by a suitable distance for laying and winding, considering that the elastic pressure roller behind can keep up with the beat at the turning point; the second problem is mainly the following rhythm of the pressure roller; the third problem requires the surface to be fitted with straight lines, and the length of the straight lines is solved under the premise of fitting accuracy <0.5 or <1, ​​so as to obtain the optimal cloth width. The overlap affects the axial tensile performance. The failure of the axial performance to keep up may cause the circumferential fibers to fall apart and not resistant to scouring.

[0436] During the automatic laying process, the laying trajectory is designed according to the idea of ​​combining parallel reciprocating laying and overlapping laying design. The reason is to avoid airflow scouring, so the last layer of winding is required to be carried out from the large end to the small end to form a structure along the airflow; at the same time, in order to improve the surface contour of overlapping laying, overlapping laying is required to be carried out in an equidistant staggered cycle. The parallel reciprocating laying design is: automatic laying is carried out from top to bottom once, then automatic laying is carried out from bottom to top once, and then a manual layer is laid to improve the axial performance; the subsequent laying is repeated until the thickness meets the design value, and the manual layer is cancelled when the final thickness is laid. The overlapping laying design is carried out from the small end to the large end, the width of the cloth tape is temporarily selected as 40mm, and the overlapping amount is 55% for laying, and the staggered cycle is laid according to 4-8 times. After the laying is carried out smoothly, in order to increase the overall sales volume, the widening of the cloth tape is gradually adjusted to 60-80mm; the feed rate is gradually increased from 20mm / r to 30mm / r.

[0437] (II) Quality issues of automatic placement molding process test:

[0438] (1) Automatic laying from top to bottom:

[0439] The main problems with the appearance quality after laying from top to bottom are that the wrinkles in the front section of the first cone of the special-shaped cabin are more obvious, and the wrinkles in the rear section of the second cone of the special-shaped cabin are intermittent.

[0440] Through simulation and test verification, it was found that the first cone could not be laid with a 60mm cloth tape, but the second cone could be laid smoothly with a 60mm cloth width, and the tension output value was controlled to be 16%.

[0441] (2) Automatic laying from bottom to top:

[0442] The appearance after laying from bottom to top shows that the wrinkles are improved after the tension output value increases, but the bridging problem is more serious.

[0443] (3) Circular reciprocating automatic placement:

[0444] Feasibility test of reciprocating laying of 40mm wide mesh prepreg. In order to avoid the influence of different tape widths on the performance of the test piece, after the 40mm tape was laid, a reciprocating laying feasibility test was carried out on its surface using a 60mm tape. The results showed serious quality problems. The existing quality problems are manifested in three aspects:

[0445] Problem 1: The width of the fabric tape is greater than the width of the splicing rubber roller, causing the splicing seam of the rubber roller to affect the flatness of the prepreg fabric;

[0446] Problem 2: There are intermittent wrinkles on the laid surface.

[0447] Question 3: Increasing the tension output value does not significantly improve wrinkles, and bridging problems occur.

[0448] Cause analysis and solution: Problem one is that the rubber roller needs to be rectified; Problem two is that it is difficult to eliminate the wrinkles when using 60mm cloth tape to lay the front section of the I-cone of the special-shaped cabin, and the wrinkle problem can be eliminated by using 40mm cloth tape.

[0449] The structure tree analysis of the influence of different tension output values ​​on the laying quality is as follows Fig.30 and Fig.31 shown.

[0450] According to the laying parameter design determined in the plan, the automatic laying and forming of the 8mm thick heat-proof layer was explored and verified, and the parameters of the first cone of the special-shaped cabin I and the second cone of the special-shaped cabin I were preliminarily determined as follows: turn on the heating at 180℃ (the sensor shows the temperature is 123℃), the tension output value is 14%, the main pressure roller pressure is 200N, the auxiliary pressure roller pressure is 65N, the film collection tension is 0.3N, the buffer tension is 1N, and the speed ratio is 100%. For the part with a larger taper of the busbar, 60mm cloth tape is used for laying, which is easy to form wrinkles or bridges, and then 40mm cloth tape is used for laying and forming; for the part with a smaller taper of the busbar, 60mm cloth tape is used for laying, and a larger width cloth tape is used for laying, and the laying cycle is reduced from 1h6min to 44min; for the non-RTCP control program, the single laying cycle is 1h7min15s, and the quality problem has been significantly improved.

[0451] (III) Summary of the automatic wrapping verification test for special-shaped cabins:

[0452] It is feasible to realize automatic laying for the current special-shaped structural products. The feasibility of automatic laying procedures and trajectories has been verified, but the efficiency needs to be improved urgently. Regardless of reciprocating laying or overlapping laying, it is recommended to use 40mm cloth width as the basis in the future. Too large cloth width is prone to large wrinkles, and too small cloth width may affect the parent direction performance. The apparent quality of reciprocating laying and overlapping laying is improved by adjusting the overlap amount to 55% and the overlap cloth tape width to 40*5%=2mm. At the same time, the cloth width is equidistantly staggered for 4-8 cycles to even out the apparent unevenness and effectively improve the surface contour.

[0453] Through multiple debugging, we have conducted preliminary exploration and verification of the factors affecting the efficiency and quality of automatic placement (currently the quality issues mainly include wrinkles, bridging and corrugation), such as Fig.32 The laying process parameters of mesh prepreg on different structural cone sections were studied, and the automatic laying molding parameters of special-shaped structure heat protection layer products were mastered.

[0454] (IV) Problems and improvement measures of laying and wrapping forming and laying process after that:

[0455] This automatic placement test took a metal shell of a special-shaped cabin with convex and concave surfaces as the object. Reciprocating placement was performed using 60mm and 40mm cloth widths (feed rate of 1 / 2 cloth width), and overlapping placement was performed using 40mm cloth width (feed rate of 5mm / r). Overall, for the part with a larger busbar taper, the use of 60mm cloth tape for laying is prone to wrinkles or bridging, and it is recommended to use 40mm cloth tape in the future; for the part with a smaller busbar taper, 60mm cloth tape can be used for laying. Using a larger width cloth tape for laying, the laying cycle is reduced from 1h6min to 44min.

[0456] It is feasible to realize automatic laying for the current special-shaped structural products, and the feasibility of the automatic laying program and trajectory has been verified, but the efficiency needs to be improved urgently; regardless of reciprocating laying or overlapping laying, it is recommended to use 40mm cloth width as the basis in the future. Too large cloth width is prone to large wrinkles, and too small cloth width may affect the parent direction performance; the surface quality of reciprocating laying and overlapping laying is acceptable, the wrinkles in the small taper part are very slight, and there are some wrinkles in the large taper part (it should not be possible to completely avoid wrinkles); the debonding opening problem at the negative curvature position was effectively solved by increasing the viscosity of the glue and cooperating with double pressure rollers to vacuum.

[0457] (1) Improvement measures:

[0458] 1) Hardware improvement: According to the status determined by the recent debugging, the main and auxiliary rollers are designed and improved, mainly including roller segmentation design, hook leg spacing optimization, lift separation film optimization, main and auxiliary roller pressure optimization combination, etc. At the same time, the pre-pressing time of the prepreg is not reduced.

[0459] 2) CNC improvement: Improve the five-axis (preferably six-axis) RTCP into the program to eliminate the "pulse" problem during the placement process and achieve continuity and smoothness of the placement trajectory.

[0460] 3) Software / program improvement: Further optimize program points to achieve better fitting effect and further improve efficiency.

[0461] Further research on the laying program was conducted to design parameters such as tension output value and laying speed that are suitable for different circumferential positions, so as to reasonably control the laying quality at different positions.

[0462] (2) Near-net-shape heating and automatic placement:

[0463] After many tests, the above problem did not change, so the hot air was turned on subsequently.

[0464] The temperature is set to 180°C (the sensor shows a temperature of 123°C);

[0465] Ambient temperature: 13°C; Ambient humidity: 77%;

[0466] The tension output value is adjusted to 14%; the main pressure roller pressure is set to 200N; the auxiliary pressure roller pressure is set to 65N; the film collection tension is set to 0.3N, the buffer tension is 1N, and the speed ratio is 100%.

[0467] When laid from bottom to top: the rear section of the second cone of the special-shaped cabin I has a slight bridge and no wrinkles, and the front section of the first cone of the special-shaped cabin I has no wrinkles but has a bridge.

[0468] When laying from top to bottom: the front section of the first cone of the special-shaped cabin I is slightly wrinkled, which has been improved; there is no bridge, and the rear section of the second cone of the special-shaped cabin I has no problem.

[0469] After many tests in the heated state, the quality of the first cone and the rear section of the second cone of the special-shaped cabin I was good.

[0470] After vacuum pre-pressing, the surface of the product after laying and forming was preliminarily measured with a ruler, and it can be seen that the surface flatness is good.

[0471] Summary: The special-shaped cabin I adopts three rounds of multiple cycles and three times of curing, and the thickness of a single round of multiple cycles is 3-5mm; according to the laying parameter design determined by the plan, the automatic laying and forming of the 8mm thick heat-resistant layer is explored and verified, and the parameters of the first cone front section and the second cone rear section of the special-shaped cabin I are determined as follows: turn on the heating 180℃ (the sensor shows the temperature is 123℃), the tension output value is 14%, the main pressure roller pressure is 200N, the auxiliary pressure roller pressure is 65N, the film collection tension is 0.3N, the buffer tension is 1N, and the speed ratio is 100%; for the part with a larger taper of the busbar, avoid the formation of wrinkles or bridges when laying with 60mm tape and use 40mm tape for laying and forming; for the part with a smaller taper of the busbar, use 60mm tape for laying, and use a larger width tape for laying, and the laying cycle is reduced from 66min to 44min; non-RTCP control program, the single laying cycle is 68min. Taking into account the resin viscosity problem of the special-shaped cabin I structure product, it is feasible to realize automatic laying in both vertical and horizontal modes. Taking into account reciprocating laying and overlapping laying, a comprehensive decision is made to use 40mm cloth width as the basis to avoid large wrinkles caused by too large cloth width and the influence of too small cloth width on the parent direction performance. The apparent quality of reciprocating laying and overlapping laying is achieved by adjusting the overlap amount to 55% and the overlap cloth tape width to 40mm*5%=2mm. At the same time, the cloth width is equidistantly staggered for 4-8 cycles within the cloth width to even out the apparent unevenness and effectively improve the surface contour.

[0472] Example 2

[0473] Comparing Example 2 with Example 1, the difference between Example 2 and Example 1 is:

[0474] Take the Alien Cabin II as an example. Fig.33 As shown, the special-shaped cabin also includes a special-shaped cabin II, which is formed by connecting the main profile of the front section and the cylindrical surface of the rear section. The overall shape envelope size is 1200mm in diameter and 1000mm in height. The main profile of the front section is composed of eight groups of convex surfaces with positive curvature and four groups of concave surfaces with negative curvature in a symmetrical structure. The eight groups of convex surfaces include two groups of convex surfaces with positive curvature, four groups of fillet surfaces, and two groups of trapezoidal surfaces that are approximately ruled surfaces, specifically including:

[0475] The special-shaped cabin II is formed by the fusion of the front end and the rear end. The front end includes an "Ω"-shaped main profile, and the rear end includes a cylindrical surface. The main profile includes multiple groups of convex surfaces and multiple groups of concave surfaces with negative curvature. The multiple groups of convex surfaces and the multiple groups of concave surfaces are relatively symmetrically arranged. The multiple groups of convex surfaces include convex surfaces with positive curvature, rounded surfaces and trapezoidal surfaces. One end of the positive curvature surface is fused to the trapezoidal surface, and the other end of the positive curvature surface is fused to the concave surface. One end of the trapezoidal surface is fused to the concave surface through the rounded surface. The near-net-shape automatic wrapping thickness of the special-shaped cabin II is 5-8mm; the special-shaped cabin II adopts modified phenolic resin, the prepreg is yellow, has good viscosity, and does not require heating during the wrapping process. The fabric tape used is C-type quartz fiber, the quartz fiber content of which is greater than 95%, the fabric width is 40mm / 60mm / 80mm, and the fabric tape structure adopts two types of plain fabric and variable twill fabric, among which the variable twill fabric tape includes: Figure 7 As shown, the laying form is a 45° direction twill fabric with large deformation for both the warp and weft, the surface is a black porcelain modified phenolic quartz fiber material, and near-net shape automatic laying is adopted;

[0476] like Fig. 9 As shown, the laying form is a small deformation twill fabric with a warp of 0° and a weft of 90°, the surface is a yellow phenolic resin quartz fiber cloth tape, and near-net shape automatic laying is adopted;

[0477] The laying form is a twill fabric with large deformation in which both the warp and weft are 45°, and a twill fabric with small deformation in which the warp is 0° and the weft is 90°. The effect of automatic laying after the two structures are laid in a cycle and superimposed is as follows Fig.34 shown.

[0478] In order to explore the laying effect of the commonly used phenolic resin heat-resistant layer of a special-shaped cabin II, the optimal laying parameters were found by adjusting the controllable influencing factors (such as tape width, heating temperature, tension, program, etc.), and combined with the previous laying experience of other cabins, data was accumulated for the formal product laying. The specific analysis process is as follows:

[0479] 1. The shell component of the special-shaped cabin II is a special structure such as Fig.33 As shown in the figure, the product changes from the "Ω" shape at the small end to the round shape at the large end. The total height of the special-shaped cabin II is 1000mm. The metal shell is cast from aluminum alloy, and the outer surface of the metal shell is a thermal protection structure. The large-area thermal protection structure of the cabin section consists of a thermal protection layer and a strain layer. The thermal protection layer is made of high-silicon oxide cloth, the resin is phenolic resin, and the thickness is 5mm. The strain layer is made of WHBS silicone rubber with a thickness of 2mm. The schematic diagram of the thermal protection structure of the special-shaped cabin II is shown in the figure below. Fig.33 shown.

[0480] 2. Product status and test difficulties:

[0481] The special-shaped cabin II product transitions from a small-end "Ω" shape to a large-end round shape. The heat protection layer is automatically laid out using self-made high-silica fiber prepreg (resin is barium phenolic resin). Due to the special structural form of the product, through analysis and summary, it is believed that the main difficulties in the product molding process are as follows:

[0482] 1) The product has a special-shaped structure. When the small end face "Ω" shape is formed into a large end round shape, it is critical to ensure that the prepreg can fit the product completely. Limited by the bonding between the tape and the mold and the deformation ability of the tape, the tape will be suspended during laying (such as Fig.35 As shown), the problem of overhead laying needs to be controlled.

[0483] 2) Since the structure of the metal shell of the special-shaped cabin II changes greatly from the small end to the large end, when the cloth tape is laid on the mold, the cloth tape needs to be deformed to meet the fitting requirements. When the curvature is too large, it will be difficult to deform, thus forming wrinkles. Therefore, it is necessary to control the wrinkle problem of the cloth tape.

[0484] 3. Process plan and process introduction:

[0485] The automatic laying and forming process of the special-shaped cabin II heat protection layer is consistent with the manual laying process. For details, see Fig.36 ;

[0486] When the product is formed, an unvulcanized silicone-based rubber sheet is first pasted on the surface of the metal shell to form a strain isolation layer, and then a high-silicon fiber mesh prepreg is laid on the surface of the strain isolation layer as a transition material between the strain isolation layer and the heat protection layer, and finally the heat protection layer is formed on its surface.

[0487] 4. Manual laying process test of heat protection layer:

[0488] (I) Strain isolation layer patch:

[0489] According to the design requirements, the large end cylindrical surface needs to be paved with 1mm thick silicone rubber, and the small end 30mm and large end 30mm (excluding the cylindrical section) need to be paved with 1mm to 2mm silicone rubber. When paving, first evenly apply single-component room temperature vulcanized silicone rubber (GD414) on the surface of the metal shell, and then bond the silicone rubber sheet to the surface of the metal shell.

[0490] When the strain isolation layer patches are bonded, the patches in each area can be spliced, and the gaps are treated in a butt-jointed manner. According to the improvement plan and measures, the silicone rubber at the mouth cover position is removed, and the removed silicone rubber part is filled with the same high-silicon prepreg cloth as the heat protection layer. The silicone rubber sheet is then evacuated. After curing at room temperature for no less than 24 hours, the evacuation is stopped and the vacuum material is removed for inspection and repair.

[0491] (II) Laying of high silicon fiber mesh cloth:

[0492] According to the improvement measures, single-component room temperature vulcanized silicone rubber (GD414) is applied on the surface of the silicone rubber patch, and then a layer of high-silicon fiber mesh cloth prepreg is evenly laid and fixed.

[0493] (III) Automatic laying and wrapping process test of heat protection layer:

[0494] In the automatic laying and winding process test of the heat protection layer, the laying of the strain isolation layer patch, high silicon fiber mesh cloth and the curing process of the heat protection layer are the same as the manual laying process, while the heat protection layer forming process is carried out by automatic laying and winding equipment. When the heat protection layer is formed, the transition layer is first formed in the same way as the manual laying. After the transition layer is laid, automatic laying and winding begins. The laying and winding is carried out from top to bottom once, and then from bottom to top once (such as Fig.37 As shown), one reciprocating movement in the above manner is called a cycle, and each cycle consists of 4 layers of prepreg. Repeat this cycle until the thickness meets the design requirements. To ensure the appearance quality, 0.2mm to 0.5mm is reserved in the thickness direction and 1 to 2 layers of prepreg are manually laid.

[0495] 5. Laying test process and analysis:

[0496] According to the observation of the winding process, when the ambient temperature is maintained between 15℃ and 20℃, the viscosity and fit of the prepreg are at the best state.

[0497] (I) The influence of different tape widths on laying:

[0498] When using 60mm wide tape and 40mm wide tape for wrapping, the wrapping effect at both edges is relatively flat without obvious wrinkles. However, when using 60mm wide tape for wrapping on the windward and leeward sides, the wrinkles are large in size and large in number. When using 40mm wide tape, the wrinkles are significantly reduced and can be completely eliminated after the subsequent pre-compression treatment.

[0499] (II) The influence of different tensions on laying effect:

[0500] In order to ensure that the tape fits the product during the laying process, the tape tension needs to be appropriately increased. According to the previous laying test, the tension should be controlled at 14% to 20% to meet the requirements of no bridging of the tape and as few wrinkles as possible. Through actual operation, it was found that when the tension was 14%, more wrinkles appeared and the height of the tape at the laying head could not be guaranteed due to too low tension, and the overlap of each turn of the tape was uneven during winding; when the tension was 18%, the tape had obvious bridging; when the tension was 16%, the bridging and wrinkles were significantly improved, and they could be eliminated during subsequent pre-pressing.

[0501] After laying out a 40mm wide tape at different tensions between 14% and 35%, the mold itself needs to be divided into two parts: the upper part (there is a negative curvature position on each side of the leeward side at about 1 / 3 of the height) needs to balance the fitting state of the negative curvature position (i.e. the bridging problem) and the wrinkle situation; the lower part (the lower part occupies about 2 / 3 of the height, and the entire shape is a convex model) only needs to consider the wrinkle problem.

[0502] a) Upper part

[0503] According to the previous experience of laying other compartments, when the requirements of ensuring that there is no bridging at the negative curvature position and as few wrinkles as possible are met, about 16% tension is the best to balance the two effects. Therefore, in this test, 14%, 16%, and 18% tensions were selected for testing at the negative curvature position. The results showed that when the tension was 14%, a large number of wrinkles appeared, and because the tension was too small, the height of the cloth tape at the laying head could not be guaranteed, and the cloth tape would collapse, making the overlap of each circle of cloth tape uneven; when the tension was 18%, obvious bridging occurred and it was difficult to press it down manually; when the tension was 16%, there was still slight bridging and wrinkling, but the relative situation was the best. The bridging problem can be solved by vacuum preloading later. The wrinkle problem is mainly caused by insufficient deformation of the high-silica fiber prepreg cloth. There is no effective solution for the time being. It is recommended to use deformable cloth tape.

[0504] b) Lower part

[0505] Since there is no negative curvature in the lower part, the tension is tested at 20%-35%. It can be seen that with the increase of tension, the laying wrinkles gradually decrease, but the reduction is not obvious after 30%. And when the tension increases to 35%, because the tension is too large, in some areas, the force of the fabric belt on the pressure roller in the x-axis direction is greater than its set pressure (260N) (Fx>Fpressure), causing the rubber pressure roller to float (such as Fig.38 As shown), the effect is relatively best when 30% tension is used in the lower area.

[0506] (III) The influence of rollers of different heights on the laying effect:

[0507] Through actual laying and wrapping, it was found that the higher the pressure roller, the worse the fit with the mold. The fit of the pressure roller directly affects the fit between the tape and the product. After using 60mm wide tape, the apparent quality of the laid-out tape was significantly improved, and the wrinkles were significantly reduced.

[0508] Therefore, the apparent quality of the paving is significantly improved after using the 60mm wide tape, and the wrinkles are significantly reduced. That is, the use of a rubber roller corresponding to the width of the tape has a greater impact on the laying effect. The reasonable use of a rubber roller with a height corresponding to the width of the tape can achieve better laying quality.

[0509] The main reason is that the surface of the product has a special-shaped structure. The higher the rubber roller is, the worse the fit with the tooling will be during the laying process. Conversely, the better the fit, the better the quality of the lay-out.

[0510] (IV) The influence of different magnifications on the laying effect:

[0511] During the laying process, different ratios (laying speeds) affect not only the laying efficiency but also the laying effect. When the laying ratio is smaller, the tape is under pressure for a longer time and the fit is better, but the efficiency is lower. Research has shown that when the ratio is greater than 70%, the equipment may shake due to excessive reciprocating acceleration in some positions. Therefore, considering the laying efficiency and effect comprehensively, the best ratio is 60% to 70%.

[0512] 6. Selection of optimal test conditions:

[0513] According to the laying situation of the previous test pieces, 40mm wide and high silica glass prepreg tapes were used for laying. The laying was divided into three times. The first laying was one cycle (i.e. 4 layers), and then pre-pressed in a vacuum oven (pre-pressing temperature system: room temperature (or 30℃)→80℃±5℃ (keeping warm for 2h), and the heating and cooling rate was 25℃ / h±5℃ / h). After the pre-pressing, the second laying began. After the second laying for one and a half cycles (i.e. 6 layers), pre-pressing was carried out again. After the pre-pressing, the product thickness was measured, and the number of layers required for the last laying was calculated based on the measured data. After the third laying, pre-pressing was carried out again. The product thickness was measured immediately after pre-pressing, and the corresponding number of layers were manually laid again according to the measurement results.

[0514] The gradient layer of the Helian product is manually laid 5 layers (completed 0-1mm thickness gradient) + automatically laid 12 layers + the outermost layer is manually laid 1 layer of repair wrapping, a total of 18 layers of prepreg cloth, the laying parameter control is shown in Table 4, the laying effect is as follows Fig.39 shown.

[0515] Table 4 Process parameters for automatic placement of special-shaped cabin II

[0516]

[0517] 7. Curing of heat protection layer

[0518] When the heat protection layer is being cured, a process skin needs to be added to the edge. According to the improvement suggestion, the process skin at the edge R angle position and the negative curvature position needs to be separated to reduce the mutual influence. At the same time, silicone rubber is added to the edge R angle position to expand the edge R glue area and increase the actual pressure of the edge R glue. The heat protection layer is cured by vacuum, and the curing temperature is: 30° (heating for 3h) - 90° (keeping for 1h, heating for 1h) - 120° (keeping for 4h, heating for 1h) - 155° (keeping for 1h, heating for 1h) - the temperature is reduced to no more than 30° above room temperature before being taken out of the oven.

[0519] 8. Main remaining problems and solutions:

[0520] By using another traditional phenolic resin for automatic laying of the special-shaped cabin II, the process flow was explored. In this process, some problems were exposed. Through analysis, corresponding improvement measures were proposed, as follows:

[0521] 1) Uneven feed control: When the number of layers increases, ridges will gradually form on the surface of the product. After analysis, there are two main reasons: on the one hand, the slitting specifications of the tape are not standard; on the other hand, the tape itself is thick, and ridges are easily formed on the surface after laying.

[0522] Solution: Strictly control the tape slitting specifications in the later stage, increase the pre-pressing times during the laying process, and cover the outermost layer with 2 to 3 layers of prepreg.

[0523] 2) There are wrinkles and bridging on one side of the negative curvature. After analysis, it is found that the main reason is that the fabric tape is too hard and has a low viscosity, so it cannot be completely deformed and bonded.

[0524] Solution: The bridging problem can be solved by manual intervention during the laying process and vacuum pre-pressing of the process package; the wrinkle problem can be controlled by improving the hardness and viscosity of the fabric tape.

[0525] By summarizing the laying test process of the special-shaped cabin II, analyzing the problems exposed in the process and operation, finding the best laying conditions and proposing improvement measures, the early laying test has met the expected requirements. At the same time, this laying process has increased the operating experience and laid the foundation for the subsequent test pieces and formal product laying.

[0526] Summary: The special-shaped cabin II adopts single curing, and the thickness of the reciprocating cycle is 5-8mm; 40mm wide and high silica glass prepreg tape is used for laying. When the requirements of no bridging of the tape and as few wrinkles as possible are met, the tension should be controlled at 14% to 20%. The laying of the special-shaped cabin I is divided into three times. The first laying is one cycle (i.e. 4 layers), and then it is vacuum heated and pre-pressed in the oven (pre-pressing temperature system: room temperature (or 30℃) → 80℃±5℃ (keep warm for 2h). The heating and cooling rate is 25℃ / h±5℃ / h.), and the second laying begins after the pre-pressing. After the second laying is one and a half cycles (i.e. 6 layers), it is pre-pressed again. After the pre-pressing, the product thickness is measured, and the number of layers required for the last laying is calculated based on the measured data. After the third laying, it is pre-pressed again, and the product thickness is measured immediately after the pre-pressing, and the corresponding number of layers are manually laid again according to the measurement results. The curing method adopted for the heat protection layer of the special-shaped cabin II is vacuum curing, and its curing temperature and time process parameters are: curing temperature 30° (heating for 3 hours) - 90° (keeping for 1 hour, heating for 1 hour) - 120° (keeping for 4 hours, heating for 1 hour) - 155° (keeping for 1 hour, heating for 1 hour) - cooling down with the furnace to no more than 30° above room temperature before taking out of the furnace.

[0527] One or more technical solutions in the embodiments of the present application also have at least the following technical effects or advantages:

[0528] (1) The method provided in the embodiment of the present application ensures smooth laying by placing multiple restrictions on automatic laying. Specifically, laying along the ground line can ensure that the quality of the cabin is the most ideal. Laying with a margin spacing reserved in the center track of the laying trajectory can ensure that the gap between the prepreg tape or the wide cloth tape is reasonable through the margin spacing reserved in the center track. Finally, by limiting the automatic laying to the seven-axis laying linkage control controlled by the RTCP function, the operation of the machine tool can be guaranteed to be more stable, while the laying time and the construction period can be shortened.

[0529] (2) The method provided in the embodiment of the present application is based on ABAQUS mesh surface trajectory planning and CATIA spiral line and surface intersection method trajectory generation, and is based on VERICUT's vertical and horizontal seven-axis laying simulation and interference collision optimization of two different structural forms of special-shaped cabins. It also uses three different post-processing technologies, namely:

[0530] 1) Post-care technology based on the horizontal normal vector principle, that is, always keep the normal vector of the laying point in the horizontal plane;

[0531] 2) Post-processing technology based on the principle of equal height of laying points, that is, always making the height of the laying point the same as the axis;

[0532] 3) The post-processing method based on the composite selection principle of the horizontal normal vector and the equal height point principle can effectively solve the interference and collision problem, even if the normal vector directions of the placement points on the left and right sides of the mold symmetry surface are deflected up and down by a certain angle, and allowed to fluctuate within a certain range.

[0533] (3) The method provided in the embodiment of the present application adopts a CNC double-column tape laying and wrapping machine with a seven-axis linkage function, which can realize the laying or tape wrapping of most special-shaped cabin structure composite shell products; taking a certain special-shaped cabin metal shell as the object, a CNC double-column tape laying and wrapping machine was used to carry out multiple rounds of automatic laying and forming process tests, and the automatic laying process was explored by adopting different cloth widths, different laying process parameters, and different laying program control cross-combinations. During the exploration process, a relatively comprehensive verification was carried out on program trajectory optimization, CNC system matching, laying output tension, hot air temperature, film winding method, laying parameter design optimization and other aspects, and finally the automatic laying and forming of a special-shaped cabin thermal protection layer test piece was realized.

[0534] (4) The method provided in the embodiment of the present application is based on the seven-axis RTCP optimization control concept and implementation of acceleration and deceleration disturbance control with speed optimization; it avoids the low laying efficiency and unstable trajectory speed when non-RTCP control is used for laying. When laying passes through the edges of the workpiece, the laying speed slows down significantly, resulting in low laying efficiency; the speed of other areas of the laid workpiece is unstable, and the speed of the concave surface is greater than that of the convex surface, resulting in large changes in the machine tool speed. In non-RTCP laying, the speed is unstable during the entire laying process, and some linkage axes will shake when speeding up, especially the C-axis of the rotary table. The shaking is very obvious; another aspect is that the laying performance is additive processing characteristics, and the floating stroke of the pressure roller cylinder is limited. After laying to a certain thickness, it is necessary to modify the tool length similar to that of five-axis machine tool cutting and then regenerate the laying forming program, which is more troublesome to operate. The main reason is that the machine tool structure is not considered when calculating the arc length of the trajectory. The multi-axis small line segment fitting is in multi-dimensional space, and the speed planning is interfered by incorrect curve fitting results. When the seven-axis RTCP function is used for the laying and winding linkage control, the kinematic structure parameters of the machine tool are taken into account when performing the kinematic solution calculation inside the system. The control principle of the RTCP function is to perform spline fitting and speed planning in the workpiece coordinate system, so that the machine tool movement is smoother, there is no frequent acceleration and deceleration, and there will be no jitter during acceleration and deceleration; the smoothness of each motion axis is improved, so that the winding effect is more efficient; when the feed rate is 2000, the laying and winding time is about 68s, compared with the non-RTCP time of about 110s, and the efficiency is increased by nearly 50%. At the same time, the seven-axis RTCP can perform knife laying and winding thickness compensation, solve the problem of thickness compensation, and thus improve the efficiency of programming. In terms of the CNC system, the multi-axis linkage RTCP control function is improved in the laying and winding trajectory control program to eliminate the "pulse" problem in the laying process and achieve the continuity and smoothness of the laying trajectory. In terms of automatic placement CNC programs, better fitting effects can be achieved and efficiency can be further improved by further optimizing the number of program points. At the same time, the placement program needs to be further studied to design dynamic adaptive adjustments of parameters such as tension output values ​​and placement speeds at different circumferential positions, so as to achieve reasonable control of placement quality at different positions.

[0535] (5) The method provided in the embodiment of the present application adopts the first domestic double-column vertical large-scale CNC laying and wrapping integrated forming equipment. All the core functional components of the laying head are made of the laying head of China Southern Airlines with independent intellectual property rights; the automatic laying programming and simulation adopt the laying software independently developed by China Southern Airlines; the domestic Huazhong CNC system HNC848 is used for eight-axis control and seven-axis linkage laying; the system is equipped with a 30m / min high-speed feed system to improve the adaptability of laying of special-shaped surfaces, and at the same time, the control through RTCP effectively improves the smoothness of the laying trajectory and the laying efficiency; a 40-60mm wide cloth tape is used, and a 55% laying overlap is set, combined with equidistant subdivision of the non-overlapping area to perform reciprocating cycle laying and forming to improve the laying contour; a 40-120mm wide cloth tape is used to adopt reciprocating cycle laying, parallel overlapping laying, oblique winding laying, spiral winding laying, etc. to achieve reciprocating cycle laying and forming with different overlap ratios to realize the laying and forming of various complex skin structures of spatial special-shaped surfaces. The main machine can achieve the laying of special-shaped curved skin with a maximum laying envelope diameter of Φ2500 and a maximum height of 3500mm, a maximum laying speed of 30m / min, a laying angle deviation of ±0.5°, a laying belt gap accuracy of ±2.5mm, a laying belt thickness deviation of ±0.5mm, an adjustable laying belt tension of 5N to 200N, a main roller pressure of more than 500N, an auxiliary roller pressure of more than 500N, an adjustable hot air temperature of up to 150°C, an automatic correction function accuracy of ±1mm, and a travel of ±10mm. The maximum rotation diameter of the C axis of the worktable is Φ2000mm, the rotation speed is 0r / min to 10r / min, and the acceleration is 70° / s 2 , the radial travel of the arm on the X axis is 1000mm, the servo feed speed is 18000mm / min, and the acceleration is 1000mm / s 2 , arm lateral movement stroke Y axis stroke 2000mm, servo feed speed 30m / min, acceleration 1000mm / s 2 , beam vertical travel Z axis 3500mm, servo feed speed 8000mm / min, acceleration 1m / s 2 , the A-axis rotation stroke of the winding head is ±90°, the servo feed speed is 20000mm / min, and the acceleration is 70° / s 2 , winding head pitch B axis travel ±30°, servo feed speed 10000mm / min, acceleration 70° / s 2 , winding head yaw C1 stroke axis ±70°, servo feed speed 10000mm / min, acceleration 70° / s 2 , U-axis speed of the winding head is 20000mm / min, acceleration is 70° / s 2 .

[0536] (6) The method provided in the embodiment of the present application adopts domestic CNC double-column vertical laying and wrapping integrated molding. The laying and wrapping efficiency of a single product compartment will be shortened from 2 days required by the traditional two-axis laying and wrapping machine mainly relying on manual work to 0.5 days, and the efficiency will be improved by more than 4 times; the laying and wrapping margin is reduced from 12-15mm to no margin, and the raw material utilization rate can be increased from 30% to 75%. While greatly reducing material costs, the cutting processing of composite materials is reduced from 2-3 times after curing to only processing openings without large-area cutting, and the cutting processing cycle of composite materials can be shortened from 7 days to 1 day.

[0537] (7) The method provided in the embodiment of the present application, because the traditional heat-proof layer adopts the ordinary winding machine + manual laying and wrapping method, its molding quality is poor, the material waste is serious, and the wall thickness of the heat-proof layer is required to be 7mm-8mm. However, due to the fatal process defects such as molding quality, the thickness of most cabins during molding by manual laying and wrapping needs to be greater than 18mm, and some products reach 23mm. The waste of raw materials is extremely serious and the number of processing times increases. After the cabin is solidified, the heat-proof layer needs to be processed at least twice, and the cabin with large surplus needs to be processed three times. After the CNC automatic laying and wrapping molding of the present application, the material cost of each product cabin can be saved by 30%, about 60,000 yuan, and the one-time processing cost can be reduced by about 45,000 yuan, and the cumulative cost per piece can be saved by 100,000 yuan.

[0538] (8) The method provided in the embodiment of the present application, through the corresponding engineering application background and needs, combines theoretical research with close engineering practice, and through various technical research and exploration, has explored a set of effective system solutions that meet the urgent needs of the project; while greatly improving product quality and molding efficiency, it reduces costs and provides a better implementation method for near-net molding of composite materials. At the same time, it avoids the defects of traditional manual laying and traditional winding, such as low efficiency, many quality defects, poor quality consistency, high cost, and long cycle; it provides a better implementation model for expanding the engineering application of composite materials.

[0539] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0540] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for near-net-shape forming of a large-scale convex and concave curved fusion shaped cabin with wide band automatic laying and winding, characterized in that: The method comprises: The special-shaped cabins with convex and concave surfaces of different structural forms are analyzed to obtain the laying trajectory of the special-shaped cabin surface; The curved surface is automatically laid and wound in a circular manner, and then solidified to obtain a large-scale convex and concave curved surface fused special-shaped cabin; Wherein, the special-shaped cabin includes special-shaped cabin I and special-shaped cabin II; The raw materials for the automatic laying and winding include resin and cloth tape, and the structure of the cloth tape is plain cloth or variable twill cloth; The thickness of the resin for automatic laying is 5 mm to 16 mm, and the width of the cloth tape for automatic laying is 40 mm to 80 mm; The automatic laying includes: automatic laying and wrapping near net shape laying by cyclic winding with eight-axis and seven-axis linkage automatic laying equipment under RTCP control conditions; The automatic laying and winding methods include vertical laying and winding and horizontal laying and winding.

2. The method according to claim 1, characterized in that: The resin used for laying and wrapping the special-shaped cabin body I is semi-ceramic modified phenolic resin WBFC-20, and the cloth tape used for laying and wrapping the special-shaped cabin body I is B-type quartz fiber; the structure of the cloth tape used for laying and wrapping the special-shaped cabin body I is a large deformation twill cloth in the warp 45° and weft 45° directions; The resin used for laying and wrapping the special-shaped cabin II is a modified phenolic resin, and the cloth tape used for laying and wrapping the special-shaped cabin II is a C-type quartz fiber; The structure of the fabric tape used for laying and wrapping the special-shaped cabin II is a small-deformation twill fabric in the directions of warp 0° and weft 90°.

3. The method according to claim 2, characterized in that The semi-ceramic modified phenolic resin WBFC-20 meets the following requirements: Powder particle size distribution: D 50 <5.5μm, resin content: 52±3%, insoluble content: 14±2%, viscosity at 25℃: 350±50mPa*s, gel time at 150℃: 130±20s, free phenol content<10%; The quartz fiber content of the B-type quartz fiber is greater than 99%, and the quartz fiber content of the C-type quartz fiber is greater than 99%.

4. The method according to claim 1, characterized in that The automatic laying includes: automatic laying and near-net-shape automatic laying based on the principles of fiber tape continuity, no cutting after laying and axial performance priority; The near-net-shape automatic laying includes unidirectional cyclic laying and bidirectional cyclic reciprocating laying; The one-way cycle laying and wrapping includes vertical laying and wrapping from top to bottom or from bottom to top, and the one-way cycle laying and wrapping also includes horizontal laying and wrapping from small end to large end or from large end to small end; The bidirectional circular reciprocating paving and wrapping includes vertical paving and wrapping from top to bottom or from bottom to top, and the bidirectional circular reciprocating paving and wrapping also includes horizontal paving and wrapping from the small end to the large end or from the large end to the small end.

5. The method according to claim 1, characterized in that: The special-shaped cabin body I is composed of a front cabin body and a rear cabin body that are fused together to form a symmetrical special-shaped shell with convex and concave surfaces. The front cabin body and the rear cabin body are both composed of a plurality of groups of convex surfaces with positive curvature and a plurality of groups of concave surfaces with negative curvature that are fused together, wherein the convex surfaces with positive curvature and the concave surfaces with negative curvature are both formed by a plurality of groups of smooth arcs fused together by spline interpolation.

6. The method according to claim 5, characterized in that A two-dimensional coordinate system of the special-shaped cabin body I is constructed with the center point of the central axis from the highest point to the lowest point of the cross section of the special-shaped cabin body I as the origin, and the front section cabin body is divided into a plurality of groups of front section convex curved surfaces and a plurality of groups of front section concave curved surfaces according to the two-dimensional coordinate system of the special-shaped cabin body I, and the front section convex curved surfaces and the front section concave curved surfaces are symmetrically arranged one by one; The front convex surface includes a first front convex surface in quadrant I, a second front convex surface in quadrant II, a third front convex surface in quadrant III, and a fourth front convex surface in quadrant IV; the front concave surface includes a first front concave surface, a second front concave surface, a third front concave surface, and a fourth front concave surface; the first front concave surface is located at the intersection of quadrant I and quadrant II, the second front concave surface is located at the intersection of quadrant II and quadrant III, the third front concave surface is located at the intersection of quadrant III and quadrant IV, and the fourth front concave surface is located at the intersection of quadrant IV and quadrant I; The first front section concave curved surface fuses the first front section convex curved surface and the second front section convex curved surface, and the second front section concave curved surface fuses the fourth front section convex curved surface and the first front section convex curved surface; The third front section concave curved surface fuses the second front section convex curved surface and the third front section convex curved surface, and the fourth front section concave curved surface fuses the third front section convex curved surface and the fourth front section convex curved surface; The curvature change degree of the first front-segment concave surface or the second front-segment concave surface is greater than the curvature change degree of the third front-segment concave surface or the fourth front-segment concave surface; The rear section cabin body is divided into a plurality of groups of rear section convex curved surfaces and a plurality of groups of rear section concave curved surfaces according to the cross section of the two-dimensional coordinates, and the rear section convex curved surfaces and the rear section concave curved surfaces are symmetrically arranged one by one; The rear convex surface includes a first rear convex surface in quadrant I, a second rear convex surface in quadrant II, a third rear convex surface in quadrant III, and a fourth rear convex surface in quadrant IV; the rear concave surface includes a first rear concave surface, a second rear concave surface, a third rear concave surface, and a fourth rear concave surface; the first rear concave surface is located at the intersection of quadrant I and quadrant II, the second rear concave surface is located at the intersection of quadrant II and quadrant III, the third rear concave surface is located at the intersection of quadrant III and quadrant IV, and the fourth rear concave surface is located at the intersection of quadrant IV and quadrant I; The first rear section concave curved surface fuses the first rear section convex curved surface and the second rear section convex curved surface, and the second rear section concave curved surface fuses the fourth rear section convex curved surface and the first rear section convex curved surface; The third rear concave surface fuses the second rear convex surface and the third rear convex surface, and the fourth rear concave surface fuses the third rear convex surface and the fourth rear convex surface; The curvature change degree of the first rear concave curved surface or the second rear concave curved surface is greater than the curvature change degree of the third rear concave curved surface or the fourth rear concave curved surface; A first rounded convex surface is provided between the second rear-segment convex surface and the first rear-segment concave surface, a second rounded convex surface is provided between the second rear-segment convex surface and the third rear-segment concave surface, a third rounded convex surface is provided between the fourth rear-segment convex surface and the second rear-segment concave surface, a fourth rounded convex surface is provided between the fourth rear-segment convex surface and the fourth rear-segment concave surface, the first rounded convex surface and the second rounded convex surface are relatively symmetrically arranged in quadrants I and III, the third rounded convex surface and the fourth rounded convex surface are relatively symmetrically arranged in quadrants II and IV, and the curvature variation degree of the first rounded convex surface or the second rounded convex surface is less than that of the third rounded convex surface or the fourth rounded convex surface; The first rear-section convex surface, the second rear-section convex surface, the third rear-section convex surface, the fourth rear-section convex surface, the first rear-section concave surface, the second rear-section concave surface, the third rear-section concave surface, the fourth rear-section concave surface, the first rounded convex surface, the second rounded convex surface, the third rounded convex surface and the fourth rounded convex surface form a large end surface, the second rear-section convex surface forms a first triangular surface with the first rounded convex surface and the second rounded convex surface in a direction away from the large end surface, and the fourth rear-section convex surface forms a second triangular surface with the third rounded convex surface and the fourth rounded convex surface in a direction away from the large end surface.

7. The method according to claim 6, characterized in that The front section cabin body and the rear section cabin body are both in a double cone shape, the longitudinal projection surface of the front section cabin body includes a set of symmetrical front section symmetry surfaces, and the semi-cone angle of the height change of the front section symmetry surface is 4.2°; The longitudinal projection surface of the rear section cabin body includes a group of symmetrical rear section symmetric surfaces, and the semi-cone angle of the height change of the rear section symmetric surfaces is 1.3°; The semi-cone angle of the height change of the third front section convex surface is 2.5°, the semi-cone angle of the height change of the first front section convex surface is 5.6°, the semi-cone angle of the height change of the third rear section convex surface is 3°, and the semi-cone angle of the height change of the first rear section convex surface is 1.3°; The included angle between the outer side and the inner side of the first triangular curved surface is 9.6°, and the included angle between the outer side and the inner side of the second triangular curved surface is 10°.

8. The method according to claim 1, characterized in that: The special-shaped cabin body also includes a special-shaped cabin body II, and the special-shaped cabin body II is formed by fusing a front end and a rear end, the front end includes a main profile in an "Ω" shape, the rear end includes a cylindrical surface, the main profile includes multiple groups of convex surfaces and multiple groups of concave surfaces with negative curvature, the multiple groups of convex surfaces and the multiple groups of concave surfaces are respectively symmetrically arranged, the multiple groups of convex surfaces include positive curvature convex surfaces, rounded surfaces and trapezoidal surfaces, one end of the positive curvature convex surface is fused to the trapezoidal surface, the other end of the positive curvature convex surface is fused to the concave surface, and one end of the trapezoidal surface is fused to the concave surface through the rounded surface.

9. The method according to claim 1, characterized in that: The analysis of the special-shaped cabin body with convex and concave surfaces of different structural forms to obtain the laying trajectory of the special-shaped cabin body surface specifically includes: Analyze the three-dimensional model structure of the special-shaped cabin with convex and concave surfaces of different structural forms; Performing meshing processing according to the three-dimensional model structure to extract solid surfaces; Based on ABAQUS mesh surface trajectory planning and CATIA spiral line-surface intersection method, trajectory generation is performed on the solid surface to obtain a simulated laying trajectory; Based on VERICUT analysis, during the vertical and horizontal wrapping processes of the special-shaped cabin, the simulated wrapping trajectory is subjected to wrapping simulation and interference collision optimization to obtain the wrapping trajectory of the special-shaped cabin curved surface.

10. The method according to claim 1, characterized in that The eight-axis and seven-axis linkage automatic laying and wrapping equipment includes a double-column vertical CNC eight-axis control seven-axis linkage laying and wrapping integrated molding equipment, and the double-column vertical CNC eight-axis control seven-axis linkage laying and wrapping integrated molding equipment specifically includes: The laying and wrapping part includes a laying and wrapping head and a laying and wrapping wrist, and the end of the laying and wrapping wrist is connected to the laying and wrapping head; the laying and wrapping head includes a pressing roller device, a prepreg tape heating device, a tape tension control system, a tape cutting device, a creel and a deviation correction device in sequence along the laying direction, and is used to realize the laying and forming of reciprocating cycles of overlapping amounts of different proportions and the laying and forming of various complex skin structures with special-shaped curved surfaces; The equipment host comprises a linear drive unit and a rotary drive unit, both of which are connected to the laying and wrapping head, the linear drive unit comprises an X linear axis, a Y linear axis and a Z linear axis in sequence, which are respectively used to realize left and right movement, front and back extension and vertical lifting of the laying and wrapping head, and the rotary drive unit comprises an A rotary axis, a B rotary axis and a C rotary axis, which are respectively used to realize the pitch, roll and yaw of the laying and wrapping head; A rotary worktable is arranged below the laying and wrapping part, and comprises a workpiece rotating axis C1, which is used to realize the spatial motion interpolation and workpiece rotation of the laying and wrapping head during the forming stage of the special-shaped cabin.

11. The method according to claim 1, characterized in that The eight-axis and seven-axis linkage automatic laying and wrapping equipment includes a gantry-type horizontal laying and wrapping equipment, and the gantry-type horizontal laying and wrapping equipment specifically includes: Gantry stand; A slide box group, wherein the slides are arranged at the left and right ends of the gantry frame and are rotatably connected to the gantry frame, and the slide box group includes a left slide box and a right slide box; A laying and wrapping head, the laying and wrapping head is arranged on the slide box group, the laying and wrapping head comprises a laying and wrapping head, the wrapping head is arranged on the side of the left slide box, the laying and wrapping head is connected to the left slide box through an X rotation axis, a Y rotation axis, a Z rotation axis, an A rotation axis, a B rotation axis and a C rotation axis respectively, so as to realize the complex movement of the wrapping head in space; The tape laying head is arranged at the lower end of the right slide box, and the tape laying head is connected to the right slide box through a three-axis swing arm.

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