A multi-degree-of-freedom multi-filament placement head with adjustable tension and a placement method

Abstract

The present invention provides a multi-degree-of-freedom multi-tow laying head with adjustable tension and a laying method, belonging to the technical field of automatic laying of composite materials. The present invention solves the contradiction between large compaction pressure and miniaturization of the laying head, tension vibration, difficulty in laying small curvature surfaces, blockage of non-linear conveying tows, and difficulty in balancing uniform pressure and heat resistance of the compaction wheel. The compaction cylinder drives all components to move together, the variable diameter heavy delivery active wheel can quickly adjust the speed, and the tension sensor is used to achieve precise tension control. The swing compaction mechanism increases the degree of freedom and greatly improves the adaptability to the curved surface. The rear guide mechanism realizes smooth guiding of the variable angle prepreg tape. The spring steel butterfly wheel is both soft and heat-resistant, and the overall structure is compact. The present invention can effectively expand the applicable occasions of the automatic fiber placement technology.

Description

Technical Field

[0001] The invention belongs to the technical field of automated fiber placement of composite materials, and specifically discloses a multi-degree-of-freedom multi-tow placement head with adjustable tension and a placement method. Background Art

[0002] Fiber placement technology is one of the important means to achieve low-cost manufacturing of carbon fiber composites. It is mainly used in the production of high-performance composite materials, especially in the manufacturing of lightweight structural parts in the aerospace, automotive, wind energy and other industries, effectively improving production efficiency and ensuring production quality.

[0003] The laying of tows in the fiber placement equipment is mainly completed by the laying head. The inventor's team has designed a Chinese patent with application number CN202311745539.5 and the invention name is a laying head and laying method for multiple parallel prepreg narrow tapes with slitting function. It has a compact structure and can increase the width and laying efficiency of the tape by laying multiple parallel narrow tapes at the same time. The laying surface has high smoothness and quality, and is generally applicable to both thermoplastic and thermosetting prepreg tapes. The inventor's team has also designed a Chinese patent with application number CN202410186874.4 and the invention name is a fiber placement manipulator and self-propelled device, and a fiber placement method. The laying head integrates the guidance, re-feeding, heating, shearing, and compaction of multiple thermoplastic prepreg tapes. It has a compact structure and works with a multi-degree-of-freedom robot arm to improve the laying rate and laying accuracy.

[0004] At present, there are still several aspects that can be improved in the laying head:

[0005] 1. In the pursuit of high-speed laying, it is inevitable that the speed of the prepreg tape will change more and more dramatically. Simply changing the unwinding speed can no longer meet the precise tension requirements, and setting up a tension mechanism will increase the complexity of the prepreg tape conveying route and increase the risk of blockage;

[0006] 2. The compaction wheel and compaction cylinder are arranged at the rear end of the frame. The compaction wheel can only achieve downward and upward movement through the compaction cylinder. When laying on a curved surface, the compaction wheel must be swung to a preset angle completely depending on the action of the carrying platform to make the prepreg tape fit the curved surface. Therefore, the placement head often needs to cooperate with a six-degree-of-freedom robotic arm to achieve the laying of complex curved surfaces. It is difficult to control the swing of the compaction wheel through the six-degree-of-freedom robotic arm, and the control requirements for the six-degree-of-freedom robotic arm are high;

[0007] 3. As the number of prepreg tapes that can be laid simultaneously increases, the requirement for compaction pressure also correspondingly rises. Increasing the diameter of the compaction cylinder or the pressure of the pressure source can increase the compaction pressure. However, the compaction cylinder is arranged at the rear end of the frame. Increasing the diameter of the compaction cylinder will increase the volume at the rear end of the laying head, making it difficult to achieve the balance between compaction pressure and the control of the laying head volume. Moreover, the increase in the volume at the rear end of the laying head easily leads to a decrease in the flexibility of the laying head, which is not conducive to precise laying. And high-pressure pressure sources have safety hazards.

[0008] 4. The commonly used compaction wheels are of two types: rigid and flexible. The metal rigid wheel has good heat resistance, and the rubber flexible wheel has more uniform pressure, but it is difficult to combine the advantages of both. Summary of the Invention

[0009] The present invention provides a multi-degree-of-freedom multi-filament laying head with adjustable tension, which solves at least one of the above technical problems, and proposes a laying method based on the multi-degree-of-freedom multi-filament laying head with adjustable tension.

[0010] The multi-degree-of-freedom multi-filament winding head with adjustable tension provided by the present invention includes a frame, a unwinding mechanism, a compaction cylinder, a front guiding mechanism, a refeeding mechanism, a shearing mechanism, a rear guiding mechanism, a heating mechanism and a swinging compaction mechanism; two sets of unwinding mechanisms are symmetrically installed on both sides of the frame; each set of unwinding mechanisms includes an unwinding wheel and an unwinding wheel driving assembly; the unwinding wheel is used for installing a material roll and is driven by the unwinding wheel driving assembly to rotate relative to the frame; the telescopic rod of the compaction cylinder is fixedly connected to the front end of the frame; the swinging compaction mechanism includes a compaction wheel, a swinging frame and a compensation cylinder; the front end of the swinging frame is rotatably connected to the rear end of the frame through a swinging shaft, and the swinging shaft is perpendicular to the connection line of the centers of the unwinding wheels on both sides of the frame; the compaction wheel is rotatably connected to the rear end of the swinging frame through a compaction wheel shaft, and the compaction wheel shaft is perpendicular to the swinging shaft; two compensation cylinders are symmetrically arranged on both sides of the frame and the swinging frame, the cylinder body of the compensation cylinder is rotatably connected to the frame, and the telescopic rod of the compensation cylinder is rotatably connected to the swinging frame, and the compensation cylinder drives the swinging frame to swing relative to the frame; the front guiding mechanism, the refeeding mechanism, the shearing mechanism and the rear guiding mechanism are sequentially installed on the frame from front to back; the refeeding mechanism includes a refeeding module and a refeeding driving assembly, and the number of refeeding modules corresponds to the number of unwinding wheels on one side of the frame; the refeeding module includes a refeeding frame and two sets of single-belt refeeding units; the refeeding frame is fixedly connected to the frame; each set of single-belt refeeding units includes a refeeding driving wheel, a driving wheel shaft, a refeeding driven wheel, a driven wheel frame, a guiding column and a refeeding driven wheel spring; the driving wheel shaft is rotatably installed on the refeeding frame and is driven to rotate by the refeeding driving assembly; the refeeding driving wheel is installed on the driving wheel shaft and rotates with the driving wheel shaft, and the diameter of the refeeding driving wheel is variable; the guiding column is perpendicular to the driving wheel shaft and is fixedly connected to the refeeding frame; the driven wheel frame is slidably sleeved on the guiding column; the refeeding driven wheel spring is sleeved on the guiding column, and both ends are respectively connected to the refeeding frame and the driven wheel frame; the refeeding driven wheel is rotatably installed on the driven wheel frame through a driven wheel shaft, the driven wheel shaft is parallel to the driving wheel shaft, the refeeding driven wheel presses the refeeding driving wheel through the refeeding driven wheel spring, and the single-strip prepreg refeeding area is between the refeeding driving wheel and the refeeding driven wheel; the single-strip prepreg refeeding areas of the two sets of single-belt refeeding units are arranged in a staggered manner; the prepreg is led out from the material roll installed on the unwinding wheel, passes through the front guiding mechanism, passes through between the refeeding driving wheel and the refeeding driven wheel, passes through the shearing mechanism and the rear guiding mechanism in sequence, and then reaches the curved surface position of the compaction wheel, and the heating mechanism is used to heat the prepreg located at the curved surface position of the compaction wheel.

[0011] In the above-mentioned multi-degree-of-freedom multi-filament bundle placement head with adjustable tension, the re-feed driving wheel includes a central wheel, a radial shaft, a variable-diameter wheel lobe, and an arc-shaped gap compensator; the central wheel is fixed on the driving wheel shaft, and a plurality of radial holes are evenly arranged on the curved surface of the central wheel; each radial shaft is slidably inserted into the corresponding radial hole, and the end of the radial shaft outside the radial hole is fixedly connected to the variable-diameter wheel lobe; the variable-diameter wheel lobe is a fan-shaped ring structure, and a plurality of variable-diameter wheel lobes are connected to form a ring arranged around the central wheel. The end surface of the variable-diameter wheel lobe arranged along the circumferential direction of the ring is the circumferential end surface, and a rotating interface and a sliding interface are respectively arranged on the circumferential end surfaces on both sides of each variable-diameter wheel lobe; the arc-shaped gap compensator is arranged between two adjacent variable-diameter wheel lobes, one side of the arc-shaped gap compensator is rotatably connected to the rotating interface of one variable-diameter wheel lobe, and the other side of the arc-shaped gap compensator is slidably inserted into the sliding interface of another variable-diameter wheel lobe; each single-belt re-feed unit further includes an elastic restraint belt and a variable-diameter driving structure; the elastic restraint belt is sleeved outside the variable-diameter wheel lobe; the variable-diameter driving structure drives a plurality of variable-diameter wheel lobes to synchronously extend outward or contract inward.

[0012] In the above-mentioned multi-degree-of-freedom multi-filament bundle placement head with adjustable tension, the end surface of the variable-diameter wheel lobe arranged along the axial direction of the ring is the axial end surface, and the axial end surfaces on both sides of each variable-diameter wheel lobe are inclined surfaces and are symmetrically arranged with the radial shaft as the axis of symmetry; the variable-diameter driving structure includes an extrusion disc, an extrusion cylinder, an extrusion cylinder support piece, and a guide frame; two extrusion discs are installed on the driving wheel shaft through keys and key grooves, the two extrusion discs are located on both sides of the re-feed driving wheel, and an extrusion surface is arranged on each extrusion disc, and the extrusion surface is attached to the axial end surface of the variable-diameter wheel lobe; the extrusion cylinder is parallel to the driving wheel shaft; two extrusion cylinder support pieces are respectively connected to the corresponding extrusion discs through thrust needle bearings. The two extrusion cylinder support pieces are respectively the extrusion cylinder support piece Ⅰ and the extrusion cylinder support piece Ⅱ. The extrusion cylinder support piece Ⅰ is fixedly connected to the cylinder body of the extrusion cylinder, and the extrusion cylinder support piece Ⅱ is fixedly connected to the telescopic rod of the extrusion cylinder; a guide hole is arranged on the extrusion cylinder support piece Ⅱ; the guide frame is fixedly connected to the re-feed frame, and a guide shaft parallel to the driving wheel shaft is arranged on the guide frame, and the guide shaft passes through the guide hole.

[0013] In the above-mentioned multi-degree-of-freedom multi-filament bundle placement head with adjustable tension, the compaction wheel includes an outer wheel made of spring steel, a spring curved lobe, and a hub; the outer wheel and the hub are concentrically arranged, and the outer wheel is located outside the hub; the spring curved lobe is a bent plate-like structure, the spring curved lobe is arranged between the outer wheel and the hub, the inner end of the spring curved lobe is inserted into the hub, and the outer end of the spring curved lobe is welded to the outer wheel; the compaction wheel shaft is fixedly connected to the rear end of the swing frame and is rotationally connected to the hub of the compaction wheel through a cylindrical roller bearing; the swing compaction mechanism further includes a strain gauge type pressure sensor; the strain gauge type pressure sensor is fixed on both sides of the swing frame and is used to detect the force difference on both sides of the compaction wheel, providing a basis for the compensation cylinder to adjust the pressure.

[0014] In the above-mentioned multi-degree-of-freedom multi-filament bundle laying head with adjustable tension, each unwinding mechanism further includes sliding bearings arranged in sequence from the inside to the outside; the inner rings and outer rings of two adjacent sliding bearings are fixedly connected; among two adjacent sliding bearings, both ends of the inner-layer sliding bearing are located outside the ends of the outer-layer sliding bearing; the inner ring of the innermost sliding bearing is fixedly connected to the frame; the unwinding wheel driving assembly includes an unwinding servo motor, an unwinding driving gear, and an unwinding driven gear; a unwinding wheel and an unwinding driven gear are fixedly sleeved outside the outer ring of each sliding bearing, the unwinding driven gear meshes with the corresponding unwinding driving gear, and the unwinding driving gear is driven to rotate by the corresponding unwinding servo motor, and the unwinding servo motors are all fixed on the frame.

[0015] In the above-mentioned multi-degree-of-freedom multi-filament bundle laying head with adjustable tension, the front guiding mechanism includes a front guiding support frame, a conical guide wheel I, a transition guide wheel, and a conical guide wheel II; the front guiding support frame is connected to the frame, and multiple front guiding channels are arranged side by side on the front guiding support frame, the number of front guiding channels corresponds to the number of unwinding wheels, conical guide wheel shafts I, transition guide wheel shafts, and conical guide wheel shafts II are symmetrically arranged on both sides of the front guiding channels, and the distances between the conical guide wheel shafts I, transition guide wheel shafts, and conical guide wheel shafts II and the front guiding channels gradually decrease; the conical guide wheel I, the transition guide wheel, and the conical guide wheel II are respectively installed on the conical guide wheel shafts I, transition guide wheel shafts, and conical guide wheel shafts II through self-aligning roller bearings, and the distances between the conical guide wheel I, the transition guide wheel, and the conical guide wheel II and the front guiding channels gradually decrease; the number of conical guide wheels I, the number of transition guide wheels, and the number of conical guide wheels II on the same side of the front guiding channels respectively correspond to the number of unwinding wheels on one side of the frame, and the tapers of the conical guide wheels I and the conical guide wheels II on the same side of the front guiding channels are opposite; the tapers of the two groups of conical guide wheels I on both sides of the front guiding channels are opposite, and the tapers of the two groups of conical guide wheels II on both sides of the front guiding channels are opposite.

[0016] In the above-mentioned multi-degree-of-freedom multi-filament bundle laying head with adjustable tension, the shearing mechanism includes a shearing frame, a tension sensor, a shearing cylinder, a tool holder, and a blade; the shearing frame is fixedly connected to the frame, and multiple independent wire feeding channels are arranged side by side on the shearing frame, the number of wire feeding channels corresponds to the number of unwinding wheels, a tension sensor installation groove and a shearing groove are arranged on each wire feeding channel, the tension sensor installation groove and the shearing groove vertically penetrate the upper surface and the lower surface of the wire feeding channel, the lower surface of the wire feeding channel is connected to the front surface and the rear surface of the tension sensor installation groove through a fillet respectively, and the upper surface and the lower surface of the wire feeding channel are connected to the rear surface of the shearing groove through a chamfer respectively; a tension sensor is installed in the tension sensor installation groove of each wire feeding channel, and the variable-angle force measuring wheel of the tension sensor is aligned with the lower surface of the wire feeding channel in the initial state; a shearing cylinder is installed above each wire feeding channel, the shearing cylinder is connected to the blade through a tool holder, and the blade is located above the shearing groove.

[0017] In the above-mentioned multi-degree-of-freedom multi-filament winding head with adjustable tension, a double center rotating table and winding columns are arranged on the frame; the double center rotating table is parallel to the connection line of the centers of the two side unwinding wheels, a guiding groove is arranged on the lower surface of the double center rotating table, the guiding groove is parallel to the connection line of the centers of the two side unwinding wheels, rotating grooves are arranged on both sides of the double center rotating table, the rotating grooves include inclined plane grooves and arc grooves located above the inclined plane grooves, the inclined plane grooves extend from the end of the double center rotating table to the bottom end of the arc grooves and the height gradually increases, and limiting grooves are arranged in the rotating grooves; two winding columns are symmetrically arranged on both sides of the guiding groove; the rear guiding mechanism includes an end guide, a flexible guide rail, a double center rotating support, a follower frame and an elastic traction rope; the end guide is an arc-shaped plate structure, and is provided with a plurality of independent wire outlet channels, the number of the wire outlet channels corresponds to the number of the unwinding wheels, the front ends of the plurality of wire outlet channels are arranged side by side, the rear ends of the plurality of wire outlet channels are arranged staggered up and down, the end guide is fixedly connected with the swing frame, the front end of the end guide is connected with the rear end of the shearing frame through the flexible guide rail, and the rear end of the end guide is tangent to the compaction wheel; a rear guiding channel communicating the wire feeding channel and the wire outlet channel is arranged in the flexible guide rail; the double center rotating support includes a rotating cross beam, a rotating vertical beam, a connecting column and a rotating column, the rotating vertical beam is perpendicular to the rotating cross beam and the top end is connected with the central position of the rotating cross beam, the connecting column is vertically connected with the bottom end of the rotating vertical beam and is perpendicular to the rotating cross beam, two rotating columns are symmetrically arranged on both sides of the rotating vertical beam and are vertically connected with the rotating cross beam, the rotating column is perpendicular to the rotating vertical beam, and a limiting ring is arranged on the rotating column; the rotating cross beam of the double center rotating support is fixedly connected with the central position of the lower surface of the flexible guide rail, and the connecting column is inserted into the guiding groove of the double center rotating table; the follower frame includes a follower cross beam and a follower vertical beam, the follower cross beam is located above the frame, a wiring column is arranged at the central position of the follower cross beam, two follower vertical beams are located on both sides of the frame and the swing shaft, the top end of the follower vertical beam is fixedly connected with the follower cross beam, and the bottom end of the follower vertical beam is fixedly connected with the swing frame; a single-side elastic traction rope bypasses the winding column and connects the connecting column of the double center rotating support and the wiring column of the follower frame; the elastic traction ropes on both sides pull down the rotating columns at both ends of the double center rotating support into the rotating grooves on both sides of the double center rotating table, and the limiting ring is matched with the limiting groove.

[0018] In the above-mentioned multi-degree-of-freedom multi-filament bundle laying head with adjustable tension, the number of unwinding wheels on one side of the frame is two, namely unwinding wheel I and unwinding wheel II; each set of unwinding mechanism includes two sliding bearings, namely sliding bearing I and sliding bearing II, and sliding bearing I is located outside sliding bearing II; an expansion sleeve I and an unwinding driven gear I are fixedly sleeved outside the outer ring of sliding bearing I, the unwinding wheel I is installed outside the expansion sleeve I, the unwinding driven gear I meshes with the corresponding unwinding driving gear I, and the unwinding driving gear I is driven to rotate by the corresponding unwinding servo motor I; an expansion sleeve II and an unwinding driven gear II are fixedly sleeved outside the outer ring of sliding bearing II, the unwinding wheel II is installed outside the expansion sleeve II, the unwinding driven gear II meshes with the corresponding unwinding driving gear II, and the unwinding driving gear II is driven to rotate by the corresponding unwinding servo motor II; in the front guiding mechanism, the number of conical guide wheels I, the number of transition guide wheels, and the number of conical guide wheels II on the same side of the front guiding channel are all two; in the refeeding mechanism, the number of refeeding modules is two, namely refeeding module I and refeeding module II, the single-prepreg refeeding areas of refeeding module I and refeeding module II are arranged with dislocation, the two driving wheel shafts in refeeding module I are respectively driving wheel shaft Ia and driving wheel shaft Ib, and the two driving wheel shafts in refeeding module II are respectively driving wheel shaft IIa and driving wheel shaft IIb; the refeeding driving assembly includes a refeeding servo motor, a refeeding gear I, a refeeding gear II, a pulley I, a synchronous belt I, a pulley II, a pulley III, a synchronous belt II and a pulley IV; the refeeding servo motor is fixed on the frame and has a braking function, and the output shaft of the refeeding servo motor is connected to the pulley I; the two refeeding gears I are respectively installed on driving wheel shaft Ia and driving wheel shaft Ib, and the two refeeding gears I mesh with each other; the two refeeding gears II are respectively installed on driving wheel shaft IIa and driving wheel shaft IIb, and the two refeeding gears II mesh with each other; the pulley II and the pulley III are respectively installed at both ends of driving wheel shaft Ia, the pulley II is arranged on the same side as the pulley I and is connected by the synchronous belt I; the pulley IV is installed on driving wheel shaft IIa, the pulley IV is arranged on the same side as the pulley III and is connected by the synchronous belt II; the refeeding gears I and the refeeding gears II rotate at the same speed; the heating mechanism includes a heating nozzle and a hot air gun, the heating nozzle is installed on the swing frame, and the hot air gun is connected to the heating nozzle.

[0019] The laying method provided by the present invention uses the above-mentioned multi-degree-of-freedom multi-filament bundle laying head with adjustable tension for laying, and includes the following steps:

[0020] S1, Install the material roll on the unwinding wheel;

[0021] S2, Pull out the prepreg from the material roll, sequentially bypass the conical guide wheel I, the transition guide wheel, the conical guide wheel II, and then pass through the front guiding channel to reach the refeeding mechanism;

[0022] S3, Cut off the power supply of the refeeding servo motor or switch it to the free rotation mode, pass the prepreg through the single-prepreg refeeding area, and enter the front end of the wire feeding channel;

[0023] S4, Lift the variable-angle force-measuring wheel of the tension sensor, and pass the prepreg tape through the installation slot of the tension sensor until it exceeds the shearing slot;

[0024] S5, Switch the re-feed servo motor to the braking state. Clamp and fix the prepreg tape with the re-feed driving wheel and the re-feed driven wheel. Start the shearing cylinder once to perform the initial shearing on the end of the prepreg tape. Start the unwind servo motor to output a constant torque in the reverse direction, and apply tension to the prepreg tape between the unwind mechanism and the re-feed mechanism;

[0025] S6, Move the multi-degree-of-freedom multi-filament placement head with adjustable tension to the starting point of the placement path. Start the re-feed servo motor to send the prepreg tape to the outlet of the end guide. At the same time, start the compensation cylinder to adjust the compaction wheel to the preset angle. Start the heating mechanism. Then the re-feed servo motor continues to work to send the prepreg tape to the curved surface position of the compaction wheel. Start the compaction cylinder to press the end of the prepreg tape onto the mandrel;

[0026] S7, Perform placement according to the placement path. During the placement process, tension appears in the prepreg tape between the re-feed mechanism and the mandrel. The re-feed servo motor drives the driving wheel shaft to rotate at the linear velocity of the movement speed of the center track of the compaction wheel. Adjust the extrusion cylinder in real time according to the tension measured by the tension sensor to change the diameter of the re-feed driving wheel and then change the re-feed speed. If the tension is greater than the set value, increase the re-feed speed. If the tension is less than the set value, decrease the re-feed speed. Adjust the thrust of the compensation cylinder through the strain gauge pressure sensors fixed on both sides of the swing frame to make the pressure received by the compaction wheel uniform;

[0027] S8, When the distance between the multi-degree-of-freedom multi-filament placement head with adjustable tension and the end point of the placement path is the length of the prepreg tape between the compaction wheel and the blade, start the shearing cylinder once to cut the prepreg tape. At the same time, switch the re-feed servo motor to the braking state. Clamp and fix the uncut prepreg tape with the re-feed driving wheel and the re-feed driven wheel. The entire multi-degree-of-freedom multi-filament placement head with adjustable tension continues to move to the end point along the placement path, and press the cut prepreg tape onto the mandrel to complete this placement. Turn off the heating mechanism and lift the compaction cylinder;

[0028] S9, If you want to continue the next placement, the multi-degree-of-freedom multi-filament placement head with adjustable tension moves to the starting point of the next placement path and repeats to enter S6;

[0029] If the placement is finished, first turn off the unwind servo motor, then turn off the re-feed servo motor. Move the multi-degree-of-freedom multi-filament placement head with adjustable tension to the power-on position, cut off the power, and directly enter S5 when powering on next time;

[0030] If the material roll on the unwinding wheel is used up, the unwinding servo motor is turned off, and the entire tension-adjustable multi-degree-of-freedom multi-tow placement head continues to move along the placement path to compact the prepreg tape between the unwinding wheel and the compacting wheel on the core mold. Then the re-feeding servo motor is turned off, and the tension-adjustable multi-degree-of-freedom multi-tow placement head is moved to the power-on position, the power is turned off, and the next startup enters S1.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The re-feeding driving wheel in the re-feeding mechanism adopts variable diameter speed regulation, which can adjust the speed of re-feeding within a certain range, and realize the precise control of the tension of each prepreg tape during laying. There is no need to set up an additional tension mechanism, which simplifies the conveying route of the prepreg tape and reduces the risk of blockage;

[0033] 2. The deflection angle of the compacting wheel is obtained by the stroke difference of the compensation cylinders on both sides to adapt to different laying angles, which increases the freedom of the laying head and reduces the requirements for the carrying platform. The curved surface laying can be achieved by mounting it on a four-degree-of-freedom gantry. Under the condition of achieving the same compaction pressure, the cost of the four-degree-of-freedom gantry is lower than that of the six-degree-of-freedom robotic arm. At the same time, pressure compensation is performed during the compaction process of the compensation cylinder to keep the force on the compacting wheel uniform.

[0034] 3. The compaction cylinder is set at the front end of the frame to drive the overall movement of the frame. The unwinding wheels are set on both sides of the frame to fully optimize the space. The volume of the tape laying head can be minimized while using a large-diameter compaction cylinder, achieving a balance between compaction pressure and tape laying head volume control, while avoiding the use of a high-pressure pressure source;

[0035] 4. The compacting wheel adopts spring steel butterfly wheel, which has greater elastic deformation than solid metal compacting wheel. It can form a small plane at the compacting point, increase compaction time, reduce residual bending stress of prepreg tape, and improve molding quality. Compared with rubber wheel, it is more resistant to high temperature, can work for a long time, and improve production efficiency. It has good heat dissipation and no need to worry about thermal failure.

[0036] In summary, the present invention solves the contradiction between large compaction pressure and miniaturization of the laying head, tension vibration, difficulty in laying small curvature surfaces, blockage of non-linear conveying bundles, and difficulty in balancing uniform pressure and heat resistance of the compaction wheel. The compaction cylinder drives all components to move together, the variable diameter heavy delivery active wheel can quickly adjust the speed, and the tension sensor is used to achieve precise tension control. The swing compaction mechanism increases the degree of freedom and greatly improves the adaptability to curved surfaces. The rear guide mechanism realizes smooth guiding of variable angle prepreg tapes. The spring steel butterfly wheel is both soft and heat-resistant, and the overall structure is compact. The present invention can effectively expand the applicable occasions of fiber automatic placement technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0038] Figure 1 Is a three-dimensional view of a multi-degree-of-freedom multi-filament placement head with adjustable tension;

[0039] Figure 2 Is a plan view of the unwinding mechanism;

[0040] Figure 3 Is a three-dimensional view of the unwinding mechanism;

[0041] Figure 4 Is a three-dimensional view of the front guiding mechanism;

[0042] Figure 5 Is a three-dimensional view of the refeeding mechanism;

[0043] Figure 6 Is Figure 5 A view in another direction;

[0044] Figure 7 Is a three-dimensional view of the refeeding module;

[0045] Figure 8 Is an assembly drawing of the refeeding driving wheel and the driving wheel shaft;

[0046] Figure 9 Is a three-dimensional view of the state transformation of the refeeding driving wheel extending outwards and contracting inwards;

[0047] Figure 10 Is a plan view of the state transformation of the refeeding driving wheel extending outwards and contracting inwards;

[0048] Figure 11 Is a three-dimensional view of the shearing mechanism;

[0049] Figure 12 Is Figure 11 A partial sectional view of;

[0050] Figure 13 Is an installation schematic diagram of the shearing mechanism, the rear guiding mechanism and the swinging compaction mechanism on the frame;

[0051] Figure 14 Is an installation schematic diagram of the double-center rotary bracket and the swivel bracket on the frame;

[0052] Figure 15 Is an installation schematic diagram of the swinging compaction mechanism on the frame;

[0053] Figure 16 Stereogram of the compaction wheel

[0054] In the figure: 1 - frame; 1.1 - double center rotary table; 1.1.1 - guiding groove; 1.1.2 - rotary groove; 1.1.3 - limiting groove; 1.2 - wire winding post

[0055] 2 - unwinding mechanism; 2.1 - unwinding wheel I; 2.2 - unwinding wheel II; 2.3 - sliding bearing I; 2.4 - sliding bearing II; 2.5 - tensioning sleeve I; 2.6 - unwinding driven gear I; 2.7 - unwinding driving gear I; 2.8 - unwinding servo motor I; 2.9 - tensioning sleeve II; 2.10 - unwinding driven gear II; 2.11 - unwinding driving gear II; 2.12 - unwinding servo motor II

[0056] 3 - compaction cylinder

[0057] 4 - front guiding mechanism; 4.1 - front guiding support frame; 4.2 - conical guide wheel I; 4.3 - transition guide wheel; 4.4 - conical guide wheel II; 4.5 - front guiding channel; 4.6 - spherical roller bearing

[0058] 5 - refeeding mechanism; 5.1 - refeeding frame; 5.2 - refeeding driving wheel; 5.2.1 - center wheel; 5.2.2 - radial shaft; 5.2.3 - variable diameter wheel flap; 5.2.4 - arc-shaped gap compensating frame; 5.3 - driving wheel shaft; 5.4 - refeeding driven wheel; 5.5 - driven wheel frame; 5.6 - guiding post; 5.7 - refeeding driven wheel spring; 5.8 - rolling ball bearing; 5.9 - support bearing; 5.10 - elastic restraint band; 5.11 - extrusion disc; 5.12 - extrusion cylinder; 5.13 - guiding frame; 5.14 - thrust needle roller bearing; 5.15 - extrusion cylinder support plate I; 5.16 - extrusion cylinder support plate II; 5.17 - refeeding servo motor; 5.18 - refeeding gear I; 5.19 - refeeding gear II; 5.20 - pulley I; 5.21 - synchronous belt I; 5.22 - pulley II; 5.23 - pulley III; 5.24 - synchronous belt II; 5.25 - pulley IV

[0059] 6 - shearing mechanism; 6.1 - shearing frame; 6.2 - tension sensor; 6.3 - shearing cylinder; 6.4 - tool rest; 6.5 - blade; 6.6 - wire feeding channel; 6.7 - tension sensor mounting groove; 6.8 - shearing groove

[0060] 7 - rear guiding mechanism; 7.1 - end guide; 7.2 - flexible guide rail; 7.3 - double center rotary support; 7.3.1 - rotary cross beam; 7.3.2 - rotary vertical beam; 7.3.3 - connecting column; 7.3.4 - rotary column; 7.3.5 - limiting ring; 7.4 - follower frame; 7.5 - elastic traction rope; 7.6 - wire outlet channel

[0061] 8 - Heating mechanism;

[0062] 9 - Oscillating compaction mechanism; 9.1 - Compaction wheel; 9.1.1 - Outer wheel; 9.1.2 - Spring flap; 9.1.3 - Hub; 9.2 - Oscillating frame; 9.3 - Compensation cylinder; 9.4 - Tapered roller bearing; 9.5 - Cylindrical roller bearing; 9.6 - Compensation cylinder mounting bracket; 9.7 - Strain gauge pressure sensor. Detailed implementation manners

[0063] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0064] In the following embodiments, along the conveying route of the prepreg tape, it is defined that the prepreg tape arriving first is the front and the one arriving later is the rear.

[0065] Embodiment 1

[0066] This embodiment provides a multi - degree - of - freedom multi - tow placement head with adjustable tension, including a frame 1, a pay - off mechanism 2, a compaction cylinder 3, a front guiding mechanism 4, a re - feeding mechanism 5, a shearing mechanism 6, a rear guiding mechanism 7, a heating mechanism 8, and an oscillating compaction mechanism 9; the frame 1 serves as the load - bearing support for the entire device; the compaction cylinder 3 is a pneumatic cylinder, and the telescopic rod of the compaction cylinder 3 is fixedly connected to the front end of the frame 1; the oscillating compaction mechanism 9 is arranged at the rear end of the frame 1; the front guiding mechanism 4, the re - feeding mechanism 5, the shearing mechanism 6, and the rear guiding mechanism 7 are sequentially installed on the frame 1 from front to back.

[0067] Two groups of pay - off mechanisms 2 are symmetrically installed on both sides of the frame 1; each group of pay - off mechanisms 2 includes a pay - off wheel and a pay - off wheel drive assembly; the pay - off wheel is used to install the material roll and is driven by the pay - off wheel drive assembly to rotate relative to the frame 1.

[0068] Each group of pay - off mechanisms 2 further includes sliding bearings arranged in sequence from inside to outside; the inner rings and outer rings of adjacent two sliding bearings are fixedly connected; among adjacent two sliding bearings, both ends of the inner - layer sliding bearing are located outside the ends of the outer - layer sliding bearing; the inner ring of the innermost sliding bearing is fixedly connected to the connecting shafts on both sides of the frame 1; the pay - off wheel drive assembly includes a pay - off servo motor, a pay - off driving gear, and a pay - off driven gear; a pay - off wheel and a pay - off driven gear are fixedly sleeved outside the outer ring of each sliding bearing, the pay - off driven gear meshes with the corresponding pay - off driving gear, the pay - off driving gear is driven by the corresponding pay - off servo motor to rotate, and the pay - off servo motors are all fixed on the frame 1.

[0069] The front guiding mechanism 4 is used for guiding between the unwinding mechanism 2 and the refeeding mechanism 5 to solve the difficulty of cross-plane wire feeding. It includes a front guiding support frame 4.1, a conical guide wheel I 4.2, a transition guide wheel 4.3, and a conical guide wheel II 4.4. The front guiding support frame 4.1 is connected to the frame 1 by screws. Multiple front guiding channels 4.5 are arranged side by side on the front guiding support frame 4.1. The number of the front guiding channels 4.5 corresponds to the number of unwinding wheels. On both sides of the front guiding channel 4.5, a conical guide wheel shaft I, a transition guide wheel shaft, and a conical guide wheel shaft II are symmetrically arranged. The distances between the conical guide wheel shaft I, the transition guide wheel shaft, the conical guide wheel shaft II and the front guiding channel 4.5 gradually decrease. The conical guide wheel I 4.2, the transition guide wheel 4.3, and the conical guide wheel II 4.4 are respectively installed on the conical guide wheel shaft I, the transition guide wheel shaft, and the conical guide wheel shaft II through self-aligning roller bearings 4.6 to realize the free swing of the guide wheels within a certain angle range to adapt to the prepreg tapes led out from coils with different radii. The distances between the conical guide wheel I 4.2, the transition guide wheel 4.3, the conical guide wheel II 4.4 and the front guiding channel 4.5 gradually decrease to realize the smooth guiding of the prepreg tape between different planes. The numbers of the conical guide wheel I 4.2, the transition guide wheel 4.3, and the conical guide wheel II 4.4 on the same side of the front guiding channel 4.5 respectively correspond to the number of unwinding wheels on one side of the frame 1. The tapers of the conical guide wheel I 4.2 and the conical guide wheel II 4.4 on the same side of the front guiding channel 4.5 are opposite. The tapers of the two groups of conical guide wheel I 4.2 on both sides of the front guiding channel 4.5 are opposite, and the tapers of the two groups of conical guide wheel II 4.4 on both sides of the front guiding channel 4.5 are opposite. The front guiding support frame 4.1 not only serves as the support of the guide wheels but also has the front guiding channels 4.5 to realize the initial positioning of the prepreg tape conveying route.

[0070] The rewinding mechanism 5 includes a rewinding module and a rewinding drive assembly. The number of rewinding modules corresponds to the number of unwinding wheels on one side of the frame 1. The rewinding module includes a rewinding frame 5.1 and two single-belt rewinding units. The rewinding frame 5.1 is fixedly connected to the frame 1 and is connected by two L-shaped brackets to form a "mouth" shape structure. Each single-belt rewinding unit includes a rewinding driving wheel 5.2, a driving wheel shaft 5.3, a rewinding driven wheel 5.4, a driven wheel bracket 5.5, a guide post 5.6, and a rewinding driven wheel spring 5.7. The driving wheel shaft 5.3 is rotatably installed on the rewinding frame 5.1 through a rolling ball bearing 5.8 and is driven to rotate by the rewinding drive assembly. The rewinding driving wheel 5.2 is installed on the driving wheel shaft 5.3 and rotates with the driving wheel shaft 5.3. The diameter of the rewinding driving wheel 5.2 is variable. The guide post 5.6 is perpendicular to the driving wheel shaft 5.3 and is fixedly connected to the rewinding frame 5.1. The driven wheel bracket 5.5 is slidably sleeved on the guide post 5.6. The rewinding driven wheel spring 5.7 is sleeved on the guide post 5.6 and its two ends are respectively connected to the rewinding frame 5.1 and the driven wheel bracket 5.5. The rewinding driven wheel 5.4 is rotatably connected to the driven wheel shaft through a support bearing 5.9. The driven wheel shaft is fixedly installed on the driven wheel bracket 5.5. The driven wheel shaft is parallel to the driving wheel shaft 5.3. The rewinding driven wheel 5.4 presses the rewinding driving wheel 5.2 through the rewinding driven wheel spring 5.7. The single pre-impregnated tape rewinding area is located between the rewinding driving wheel 5.2 and the rewinding driven wheel 5.4. The single pre-impregnated tape rewinding areas of the two single-belt rewinding units are arranged in a staggered manner.

[0071] In the above-described rewinding mechanism 5, the rewinding driving wheel 5.2 realizes variable diameter through the following structure: The rewinding driving wheel 5.2 includes a central wheel 5.2.1, a radial shaft 5.2.2, a variable-diameter vane 5.2.3, and an arc-shaped gap-filling frame 5.2.4; the central wheel 5.2.1 is fixed on the driving wheel shaft 5.3, and a plurality of radial holes are uniformly arranged on the curved surface of the central wheel 5.2.1; each radial shaft 5.2.2 is slidably inserted into the corresponding radial hole, and the end of the radial shaft 5.2.2 outside the radial hole is fixedly connected to the variable-diameter vane 5.2.3; the variable-diameter vane 5.2.3 is of a sector ring structure, and a plurality of variable-diameter vanes 5.2.3 are connected to form a ring arranged around the central wheel 5.2.1. The end face of the variable-diameter vane 5.2.3 arranged along the circumferential direction of the ring is the circumferential end face, and a rotating interface and a sliding interface are respectively arranged on the circumferential end faces on both sides of each variable-diameter vane 5.2.3; the arc-shaped gap-filling frame 5.2.4 is arranged between two adjacent variable-diameter vanes 5.2.3. One side of the arc-shaped gap-filling frame 5.2.4 is rotatably connected to the rotating interface of one variable-diameter vane 5.2.3, and the other side of the arc-shaped gap-filling frame 5.2.4 is slidably inserted into the sliding interface of another variable-diameter vane 5.2.3; when a plurality of variable-diameter vanes 5.2.3 synchronously extend outwards, the arc-shaped gap-filling frame 5.2.4 is pulled out to fill the gap between two adjacent variable-diameter vanes 5.2.3, providing pressure support for the rewinding driven wheel 5.3; when a plurality of variable-diameter vanes 5.2.3 synchronously contract inwards, the arc-shaped gap-filling frame 5.2.4 can be pushed into the sliding interface of the variable-diameter vane 5.2.3; each single-belt rewinding unit further includes an elastic restraint belt 5.10 and a variable-diameter driving structure; the elastic restraint belt 5.10 is sleeved outside the variable-diameter vane 5.2.3, which can not only provide a contraction force for the inward contraction of the rewinding driving wheel 5.2, but also improve the surface friction of the rewinding driving wheel 5.2; the variable-diameter driving structure drives a plurality of variable-diameter vanes 5.2.3 to synchronously extend outwards or contract inwards.

[0072] In the above-described rewinding mechanism 5, the variable-diameter driving structure can adopt a telescopic cylinder. A telescopic cylinder is installed in each radial hole, and the telescopic rod of the telescopic cylinder is connected to the radial shaft 5.2.2. The synchronous action of a plurality of telescopic cylinders realizes the synchronous outward extension or inward contraction of a plurality of variable-diameter vanes 5.2.3.

[0073] In order to reduce the installation difficulty and the control difficulty, the following method is adopted in this embodiment to achieve the variable diameter of the refeeding driving wheel 5.2: The end face of the variable diameter wheel flap 5.2.3 arranged along the axial direction of the ring is the axial end face, and the axial end faces on both sides of each variable diameter wheel flap 5.2.3 are inclined surfaces and are symmetrically arranged with respect to the radial axis 5.2.2; The variable diameter driving structure includes an extrusion disc 5.11, an extrusion cylinder 5.12, an extrusion cylinder support piece and a guide frame 5.13; The two extrusion discs 5.11 are installed on the driving wheel shaft 5.3 through keys and key grooves, and the two extrusion discs 5.11 are located on both sides of the refeeding driving wheel 5.2. An extrusion surface is provided on each extrusion disc 5.11, and the extrusion surface is attached to the axial end face of the variable diameter wheel flap 5.2.3; The extrusion cylinder 5.12 is parallel to the driving wheel shaft 5.3; The two extrusion cylinder support pieces are respectively connected to the corresponding extrusion discs 5.11 through thrust needle bearings 5.14 and are arranged in an arch shape to make room for the installation of the extrusion cylinder 5.12. The thrust needle bearings 5.14 can achieve the transmission of the extrusion force. The two extrusion cylinder support pieces are respectively the extrusion cylinder support piece I 5.15 and the extrusion cylinder support piece II 5.16. The extrusion cylinder support piece I 5.15 is fixedly connected to the cylinder body of the extrusion cylinder 5.12, and the extrusion cylinder support piece II 5.16 is fixedly connected to the telescopic rod of the extrusion cylinder 5.12; A guide hole is provided on the extrusion cylinder support piece II 5.16; The guide frame 5.13 is fixedly connected to the refeeding frame 5.1. A guide shaft parallel to the driving wheel shaft 5.3 is provided on the guide frame 5.13, and the guide shaft passes through the guide hole to ensure that the extrusion cylinder support piece does not rotate with the driving wheel shaft 5.3 and moves parallel to the driving wheel shaft 5.3. In this embodiment, the extrusion cylinder 5.12 uses an electric cylinder.

[0074] The shearing mechanism 6 includes a shearing frame 6.1, a tension sensor 6.2, a shearing cylinder 6.3, a tool rest 6.4 and a blade 6.5; the shearing frame 6.1 is fixedly connected to the frame 1, and a plurality of independent wire feeding channels 6.6 are arranged side by side on the shearing frame 6.1. The number of the wire feeding channels 6.6 corresponds to the number of unwinding wheels. A tension sensor mounting groove 6.7 and a shearing groove 6.8 are arranged on each wire feeding channel 6.6. The tension sensor mounting groove 6.7 and the shearing groove 6.8 vertically penetrate the upper surface and the lower surface of the wire feeding channel 6.6. The lower surface of the wire feeding channel 6.6 is connected to the front surface and the rear surface of the tension sensor mounting groove 6.7 respectively through round corners. The upper surface and the lower surface of the wire feeding channel 6.6 are connected to the rear surface of the shearing groove 6.8 respectively through chamfers. The setting of the chamfers can facilitate the passing of the free end of the prepreg tape more conveniently; a tension sensor 6.2 is installed in the tension sensor mounting groove 6.7 of each wire feeding channel 6.6. The variable-angle force measuring wheel of the tension sensor 6.2 is aligned with the lower surface of the wire feeding channel 6.6 in the initial state, and the two round corners and the variable-angle force measuring wheel form a determined force receiving angle to ensure accurate force measurement; a shearing cylinder 6.3 is installed above each wire feeding channel 6.6. The shearing cylinder 6.3 is connected to the blade 6.5 through the tool rest 6.4. The blade 6.5 is located above the shearing groove 6.8. In this embodiment, the shearing cylinder 6.3 adopts a pneumatic cylinder.

[0075] The swinging compaction mechanism 9 includes a compaction wheel 9.1, a swinging frame 9.2 and a compensation cylinder 9.3; a swinging shaft is fixedly arranged at the rear end of the frame 1, and the swinging shaft is perpendicular to the connecting line of the centers of the unwinding wheels on both sides of the frame 1; the front end of the swinging frame 9.2 is connected to the swinging shaft through two symmetrically and oppositely installed tapered roller bearings 9.4, and a compaction wheel shaft perpendicular to the swinging shaft is arranged at the rear end of the swinging frame 9.2; the compaction wheel 9.1 is connected to the compaction wheel shaft through a cylindrical roller bearing 9.5; two compensation cylinders 9.3 are symmetrically arranged on both sides of the frame 1 and the swinging frame 9.2. The cylinder body of the compensation cylinder 9.3 is rotatably connected to a compensation cylinder mounting bracket 9.6, and the compensation cylinder mounting bracket 9.6 is fixed on the frame 1. The telescopic rod of the compensation cylinder 9.3 is rotatably connected to the swinging frame 9.2. The compensation cylinder 9.3 drives the swinging frame 9.2 to swing relative to the frame 1. When the frame 1 and the swinging frame 9.2 are not in straight-line compaction, the forces on both sides of the compaction wheel 9.1 are not balanced, and the pressure compensation needs to be realized by relying on the compensation cylinder 9.3. In this embodiment, the compensation cylinder 9.3 adopts a pneumatic cylinder.

[0076] In the above-mentioned swing compaction mechanism 9, the compaction wheel 9.1 includes an outer wheel 9.1.1 made of spring steel, spring curved petals 9.1.2 and a hub 9.1.3, so as to obtain a larger elastic deformation space and stronger heat dissipation and heat resistance capabilities; the outer wheel 9.1.1 and the hub 9.1.3 are concentrically arranged, and the outer wheel 9.1.1 is located outside the hub 9.1.3; the spring curved petals 9.1.2 are in a bent plate-like structure, and the spring curved petals 9.1.2 are arranged between the outer wheel 9.1.1 and the hub 9.1.3. The inner end of the spring curved petals 9.1.2 is inserted into the hub 9.1.3, and the outer end of the spring curved petals 9.1.2 is welded to the outer wheel 9.1.1; the swing compaction mechanism 9 further includes a strain gauge pressure sensor 9.7; the strain gauge pressure sensor 9.7 is fixed on both sides of the swing frame 9.2 and is used to detect the force difference on both sides of the compaction wheel 9.1, providing a basis for the compensation cylinder 9.3 to adjust the pressure.

[0077] A double center turntable 1.1 and a wire winding post 1.2 are arranged on the frame 1; the double center turntable 1.1 is parallel to the connection line of the centers of the two unwinding wheels on both sides. A guide groove 1.1.1 is provided on the lower surface of the double center turntable 1.1, and the guide groove 1.1.1 is parallel to the connection line of the centers of the two unwinding wheels on both sides. Rotary grooves 1.1.2 are provided on both sides of the double center turntable 1.1. The rotary grooves 1.1.2 include inclined grooves and arc grooves located above the inclined grooves. The inclined grooves extend from the end of the double center turntable 1.1 to the bottom end of the arc grooves and the height gradually increases. A limit groove 1.1.3 is provided in the rotary grooves 1.1.2; the two wire winding posts 1.2 are symmetrically arranged on both sides of the guide groove 1.1.1.

[0078] The rear guiding mechanism 7 includes an end guide 7.1, a flexible guide rail 7.2, a double-center rotary bracket 7.3, a follower frame 7.4, and an elastic traction rope 7.5; the end guide 7.1 is an arc-shaped plate structure, provided with a plurality of independent wire outlet channels 7.6, the number of the wire outlet channels 7.6 corresponding to the number of unwinding wheels, the front ends of the plurality of wire outlet channels 7.6 being arranged side by side, the rear ends of the plurality of wire outlet channels 7.6 being arranged staggeredly up and down, the end guide 7.1 being fixedly connected to the swing frame 9.2, the front end of the end guide 7.1 being connected to the rear end of the shearing frame 6.1 through the flexible guide rail 7.2, the rear end of the end guide 7.1 being tangent to the compaction wheel 9.1; the end guide 7.1 misplaces and lifts the side-by-side prepreg tapes and overlaps them with each other, realizing zero clearance for the laying of the tow after final compaction; a rear guiding channel communicating the wire feeding channel 6.6 and the wire outlet channel 7.6 is arranged in the flexible guide rail 7.2; the double-center rotary bracket 7.3 includes a rotary cross beam 7.3.1, a rotary vertical beam 7.3.2, a connecting column 7.3.3, and a rotary column 7.3.4, the rotary vertical beam 7.3.2 being perpendicular to the rotary cross beam 7.3.1 and the top end thereof being connected to the central position of the rotary cross beam 7.3.1, the connecting column 7.3.3 being vertically connected to the bottom end of the rotary vertical beam 7.3.2 and perpendicular to the rotary cross beam 7.3.1, two rotary columns 7.3.4 being symmetrically arranged on both sides of the rotary vertical beam 7.3.2 and perpendicularly connected to the rotary cross beam 7.3.1, the rotary column 7.3.4 being perpendicular to the rotary vertical beam 7.3.2, and a limiting ring 7.3.5 being arranged on the rotary column 7.3.4; the rotary cross beam 7.3.1 of the double-center rotary bracket 7.3 is fixedly connected to the central position of the lower surface of the flexible guide rail 7.2, and the connecting column 7.3.3 is inserted into the guide groove 1.1.1 of the double-center rotary table 1.1; the follower frame 7.4 includes a follower cross beam and a follower vertical beam, the follower cross beam being located above the frame 1, a wiring post being arranged at the central position of the follower cross beam, two follower vertical beams being located on both sides of the frame 1 and the swing shaft, the top ends of the follower vertical beams being fixedly connected to the follower cross beam, and the bottom ends of the follower vertical beams being fixedly connected to the swing frame 9.2; the single-side elastic traction rope 7.5 bypasses the winding post 1.2 and connects the connecting column 7.3.3 of the double-center rotary bracket 7.3 and the wiring post of the follower frame 7.4; the elastic traction ropes 7.5 on both sides pull down the rotary columns 7.3.4 at both ends of the double-center rotary bracket 7.3 into the rotary grooves 1.1.2 on both sides of the double-center rotary table 1.1, and the limiting ring 7.3.5 cooperates with the limiting groove 1.1.3.

[0079] When the rack 1 and the swing frame 9.2 are linearly compacted, the elastic traction ropes 7.5 on both sides are in balanced force, and the rotating columns 7.3.4 at both ends of the double-center rotating bracket 7.3 are located in the inclined slots on both sides of the double-center rotating table 1.1; when the rack 1 and the swing frame 9.2 are not linearly compacted, assuming that the compaction wheel 9.1 deviates towards the A side of the rack 1, the rotating frame 7.4 relatively deviates towards the B side of the rack 1, making the elastic traction rope 7.5 on the A side bear a greater force, pulling the double-center rotating bracket 7.3 to move towards the A side. The rotating column 7.3.4 on the B side slides upward along the inclined slot into the arc slot, and the rotating column 7.3.4 on the A side moves upward to disengage from the rotating slot 1.1.2. Subsequently, the rotating column 7.3.4 on the B side rotates along the arc slot to lift the A side of the double-center rotating bracket 7.3, and lift and smooth out the flexible guide rail 7.2 with compressed stroke on the A side, achieving smooth guiding; the reverse is also true.

[0080] The prepreg tape is led out from the material roll installed on the unwinding wheel, passes through the front guiding mechanism 4, passes between the heavy-feed driving wheel 5.2 and the heavy-feed driven wheel 5.3, and reaches the curved surface position of the compaction wheel 9.1 after passing through the shearing mechanism 6 and the rear guiding mechanism 7 in sequence. The heating mechanism 8 is used to heat the prepreg tape located at the curved surface position of the compaction wheel 9.1.

[0081] Embodiment 2

[0082] This embodiment provides a multi-degree-of-freedom multi-filament tape laying head with adjustable tension, which can lay four prepreg tapes simultaneously.

[0083] The number of unwinding wheels on one side of the rack 1 is two, namely the unwinding wheel I 2.1 and the unwinding wheel II 2.2; each set of unwinding mechanism 2 includes two sliding bearings, namely the sliding bearing I 2.3 and the sliding bearing II 2.4, and the sliding bearing I 2.3 is located outside the sliding bearing II 2.4; an expansion sleeve I 2.5 and an unwinding driven gear I 2.6 are fixedly sleeved outside the outer ring of the sliding bearing I 2.3. The unwinding wheel I 2.1 is installed outside the expansion sleeve I 2.5, and the unwinding driven gear I 2.6 meshes with the corresponding unwinding driving gear I 2.7, and the unwinding driving gear I 2.7 is driven to rotate by the corresponding unwinding servo motor I 2.8; an expansion sleeve II 2.9 and an unwinding driven gear II 2.10 are fixedly sleeved outside the outer ring of the sliding bearing II 2.4. The unwinding wheel II 2.2 is installed outside the expansion sleeve II 2.9, and the unwinding driven gear II 2.10 meshes with the corresponding unwinding driving gear II 2.11, and the unwinding driving gear II 2.11 is driven to rotate by the corresponding unwinding servo motor II 2.12. The unwinding mechanism 2 on the A side of the rack 1 leads out the No. 1 and No. 2 prepreg tapes, and the unwinding mechanism 2 on the B side of the rack 1 leads out the No. 3 and No. 4 prepreg tapes.

[0084] In the front guiding mechanism 4, the number of the conical guide wheels I 4.2, the number of the transition guide wheels 4.3, and the number of the conical guide wheels II 4.4 on the same side of the front guiding channel 4.5 are all two.

[0085] In the rewinding mechanism 5, the number of rewinding modules is two, namely rewinding module I and rewinding module II. Rewinding module I rewinds the No. 1 and No. 3 prepreg tapes, and rewinding module II rewinds the No. 2 and No. 4 prepreg tapes. The single-prepreg-tape rewinding areas of rewinding module I and rewinding module II are arranged with a dislocation. The two driving wheel shafts 5.3 in rewinding module I are respectively driving wheel shaft Ia and driving wheel shaft Ib, and the two driving wheel shafts 5.3 in rewinding module II are respectively driving wheel shaft IIa and driving wheel shaft IIb. The rewinding drive assembly includes a rewinding servo motor 5.17, a rewinding gear I 5.18, a rewinding gear II 5.19, a pulley I 5.20, a synchronous belt I 5.21, a pulley II 5.22, a pulley III 5.23, a synchronous belt II 5.24 and a pulley IV 5.25. The rewinding servo motor 5.17 is fixed on the frame 1 and has a braking function. The output shaft of the rewinding servo motor 5.17 is connected to the pulley I 5.20. The two rewinding gears I 5.18 are respectively installed on the driving wheel shaft Ia and the driving wheel shaft Ib, and the two rewinding gears I 5.18 mesh with each other. The two rewinding gears II 5.19 are respectively installed on the driving wheel shaft IIa and the driving wheel shaft IIb, and the two rewinding gears II 5.19 mesh with each other. The pulley II 5.22 and the pulley III 5.23 are respectively installed at both ends of the driving wheel shaft Ia. The pulley II 5.22 is arranged on the same side as the pulley I 5.20 and is connected through the synchronous belt I 5.21. The pulley IV 5.25 is installed on the driving wheel shaft IIa. The pulley IV 5.25 is arranged on the same side as the pulley III 5.23 and is connected through the synchronous belt II 5.24. The rewinding gears I 5.18 and the rewinding gears II 5.19 rotate at the same speed. The two driving wheel shafts 5.3 within the same rewinding module are driven through a same-speed reverse gear set. The four driving wheel shafts 5.3 of the two rewinding modules rotate at the same speed. The two driving wheel shafts 5.3 located below rotate forward, and the two driving wheel shafts 5.3 located above rotate reversely, realizing the belt feeding in the same direction. The four driving wheel shafts 5.3 are driven by the same servo motor, simplifying the complexity of the transmission. The axial end face of the variable-diameter wheel lobe 5.2.3 and the extrusion surface of the extrusion disk 5.11 are both 45 degrees.

[0086] In the shearing mechanism 6, the lower surface of the wire feeding channel 6.6 is connected to the front surface and the rear surface of the tension sensor installation groove 6.7 respectively through 1 mm round corners. The upper surface and the lower surface of the wire feeding channel 6.6 are connected to the rear surface of the shearing groove 6.8 respectively through 60-degree 0.5 mm chamfers.

[0087] The heating mechanism 8 includes a heating nozzle and a hot air gun. The heating nozzle is installed on the swing frame 9.2, and the hot air gun is connected to the heating nozzle.

[0088] Embodiment 3

[0089] This embodiment provides a laying method, which uses the above-mentioned multi-degree-of-freedom multi-filament laying head with adjustable tension for laying, and includes the following steps:

[0090] S1, Install the material roll on the unwinding wheel;

[0091] S2, Pull out the prepreg tape from the material roll, successively bypass the conical guide wheel I 4.2, the transition guide wheel 4.3, the conical guide wheel II 4.4, and then pass through the front guide channel 4.5 to reach the refeeding mechanism 5;

[0092] S3, Cut off the power supply of the refeeding servo motor 5.17 or switch it to the free rotation mode, pass the prepreg tape through the single-strip prepreg refeeding area, and enter the front end of the wire feeding channel 6.6;

[0093] S4, Lift the variable-angle force measuring wheel of the tension sensor 6.2, pass the prepreg tape through the tension sensor mounting groove 6.7 until it exceeds the shear groove 6.8;

[0094] S5, Switch the refeeding servo motor 5.17 to the braking state, the refeeding driving wheel 5.2 and the refeeding driven wheel 5.4 clamp and fix the prepreg tape, start the shearing cylinder 6.3 once to perform the primary shearing on the end of the prepreg tape, and start the unwinding servo motor to output a constant torque in the reverse direction to apply tension to the prepreg tape between the unwinding mechanism 2 and the refeeding mechanism 5;

[0095] S6, Move the multi-degree-of-freedom multi-filament laying head with adjustable tension to the starting point of the laying path, start the refeeding servo motor 5.17, send the prepreg tape to the outlet of the end guide 7.1, at the same time start the compensation cylinder 9.3 to adjust the compaction wheel 9.1 to the preset angle, start the heating mechanism 8, and then the refeeding servo motor 5.17 continues to work to send the prepreg tape to the curved surface position of the compaction wheel 9.1, and start the compaction cylinder 3 to press the end of the prepreg tape onto the mandrel;

[0096] S7, Perform laying according to the laying path. During the laying process, when there is tension in the prepreg tape between the refeeding mechanism 5 and the mandrel, the refeeding servo motor 5.17 drives the driving wheel shaft 5.3 to rotate at the linear velocity of the movement speed of the center trajectory of the compaction wheel 9.1, and adjusts the extrusion cylinder 5.12 in real time according to the tension measured by the tension sensor 6.2 to change the diameter of the refeeding driving wheel 5.2 and then change the refeeding speed. If the tension is greater than the set value, increase the refeeding speed; if the tension is less than the set value, decrease the refeeding speed. Adjust the thrust of the compensation cylinder 9.3 through the strain gauge pressure sensors 9.7 fixed on both sides of the swing frame 9.2 to make the pressure received by the compaction wheel 9.1 uniform;

[0097] When the distance between the multi-degree-of-freedom multi-filament winding head with adjustable tension and the end point of the winding path is equal to the length of the prepreg tape between the compaction wheel 9.1 and the blade 6.5, start the shearing cylinder 6.3 once to cut the prepreg tape. At the same time, switch the refeeding servo motor 5.17 to the braking state. The refeeding driving wheel 5.2 and the refeeding driven wheel 5.4 clamp and fix the uncut prepreg tape. The entire multi-degree-of-freedom multi-filament winding head with adjustable tension continues to move along the winding path to the end point, compact the cut prepreg tape on the mandrel, complete the current winding, turn off the heating mechanism 8, and lift the compaction cylinder 3;

[0098] S9, if the next winding is to be continued, the multi-degree-of-freedom multi-filament winding head with adjustable tension moves to the starting point of the next winding path and repeats to enter S6;

[0099] If the winding is finished, first turn off the unwinding servo motor, then turn off the refeeding servo motor 5.17, move the multi-degree-of-freedom multi-filament winding head with adjustable tension to the starting position, cut off the power supply, and directly enter S5 at the next startup;

[0100] If the material roll on the unwinding wheel is used up, turn off the unwinding servo motor. The entire multi-degree-of-freedom multi-filament winding head with adjustable tension continues to move along the winding path, compact the prepreg tape between the unwinding wheel and the compaction wheel on the mandrel, then turn off the refeeding servo motor 5.17, move the multi-degree-of-freedom multi-filament winding head with adjustable tension to the starting position, cut off the power supply, and enter S1 at the next startup.

[0101] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-degree-of-freedom multi-filament placement head with adjustable tension, characterized in that, It includes a frame (1), an unwinding mechanism (2), a compaction cylinder (3), a front guiding mechanism (4), a refeeding mechanism (5), a shearing mechanism (6), a rear guiding mechanism (7), a heating mechanism (8) and a swing compaction mechanism (9); Two groups of unwinding mechanisms (2) are symmetrically installed on both sides of the frame (1); Each group of unwinding mechanisms (2) includes an unwinding wheel and an unwinding wheel driving assembly; The unwinding wheel is used for installing a material roll and is driven by the unwinding wheel driving assembly to rotate relative to the frame (1); The telescopic rod of the compaction cylinder (3) is fixedly connected to the front end of the frame (1); The swing compaction mechanism (9) includes a compaction wheel (9.1), a swing frame (9.2) and a compensation cylinder (9.3); The front end of the swing frame (9.2) is rotatably connected to the rear end of the frame (1) through a swing shaft, and the swing shaft is perpendicular to the connection line of the centers of the unwinding wheels on both sides of the frame (1); The compaction wheel (9.1) is rotatably connected to the rear end of the swing frame (9.2) through a compaction wheel shaft, and the compaction wheel shaft is perpendicular to the swing shaft; Two compensation cylinders (9.3) are symmetrically arranged on both sides of the frame (1) and the swing frame (9.2). The cylinder body of the compensation cylinder (9.3) is rotatably connected to the frame (1), and the telescopic rod of the compensation cylinder (9.3) is rotatably connected to the swing frame (9.2). The compensation cylinder (9.3) drives the swing frame (9.2) to swing relative to the frame (1); The front guiding mechanism (4), the refeeding mechanism (5), the shearing mechanism (6) and the rear guiding mechanism (7) are sequentially installed on the frame (1) from front to back; The refeeding mechanism (5) includes a refeeding module and a refeeding driving assembly, and the number of refeeding modules corresponds to the number of unwinding wheels on one side of the frame (1); The refeeding module includes a refeeding frame (5.1) and two groups of single-belt refeeding units; The refeeding frame (5.1) is fixedly connected to the frame (1); Each group of single-belt refeeding units includes a refeeding driving wheel (5.2), a driving wheel shaft (5.3), a refeeding driven wheel (5.4), a driven wheel frame (5.5), a guiding column (5.6) and a refeeding driven wheel spring (5.7); The driving wheel shaft (5.3) is rotatably installed on the refeeding frame (5.1) and is driven to rotate by the refeeding driving assembly; The refeeding driving wheel (5.2) is installed on the driving wheel shaft (5.3) and rotates with the driving wheel shaft (5.3). The diameter of the refeeding driving wheel (5.2) is variable; The guiding column (5.6) is perpendicular to the driving wheel shaft (5.3) and is fixedly connected to the refeeding frame (5.1); The driven wheel frame (5.5) is slidably sleeved on the guiding column (5.6); The refeeding driven wheel spring (5.7) is sleeved on the guiding column (5.6), and both ends are respectively connected to the refeeding frame (5.1) and the driven wheel frame (5.5); The refeeding driven wheel (5.4) is rotatably installed on the driven wheel frame (5.5) through a driven wheel shaft. The driven wheel shaft is parallel to the driving wheel shaft (5.3). The refeeding driven wheel (5.4) presses the refeeding driving wheel (5.2) through the refeeding driven wheel spring (5.7). The area between the refeeding driving wheel (5.2) and the refeeding driven wheel (5.4) is a single-strip prepreg refeeding area; The single pre-impregnated tape refeeding areas of two groups of single-tape refeeding units are arranged with dislocation; The pre-impregnated tape is led out from a material roll installed on a pay-off reel, passes through a front guiding mechanism (4), passes between a refeeding driving wheel (5.2) and a refeeding driven wheel (5.4), successively passes through a shearing mechanism (6) and a rear guiding mechanism (7), and then reaches the curved surface position of a compaction wheel (9.1). A heating mechanism (8) is used to heat the pre-impregnated tape at the curved surface position of the compaction wheel (9.1).

2. The tension-adjustable multi-degree-of-freedom multi-filament placement head according to claim 1, wherein The refeeding driving wheel (5.2) includes a central wheel (5.2.1), a radial shaft (5.2.2), a variable-diameter wheel lobe (5.2.3), and an arc-shaped gap-filling frame (5.2.4); The central wheel (5.2.1) is fixed on a driving wheel shaft (5.3), and a plurality of radial holes are uniformly arranged on the curved surface of the central wheel (5.2.1); Each radial shaft (5.2.2) is slidably inserted into a corresponding radial hole, and the end of the radial shaft (5.2.2) outside the radial hole is fixedly connected to the variable-diameter wheel lobe (5.2.3); The variable-diameter wheel lobe (5.2.3) is in a sector ring structure, and a plurality of variable-diameter wheel lobes (5.2.3) are joined to form a ring arranged around the central wheel (5.2.1). The end surface of the variable-diameter wheel lobe (5.2.3) arranged along the circumferential direction of the ring is a circumferential end surface, and a rotating interface and a sliding interface are respectively arranged on the circumferential end surfaces on both sides of each variable-diameter wheel lobe (5.2.3); The arc-shaped gap-filling frame (5.2.4) is arranged between two adjacent variable-diameter wheel lobes (5.2.3). One side of the arc-shaped gap-filling frame (5.2.4) is rotatably connected to the rotating interface of one variable-diameter wheel lobe (5.2.3), and the other side of the arc-shaped gap-filling frame (5.2.4) is slidably inserted into the sliding interface of another variable-diameter wheel lobe (5.2.3); Each group of single-tape refeeding units further includes an elastic restraint belt (5.10) and a variable-diameter driving structure; The elastic restraint belt (5.10) is sleeved outside the variable-diameter wheel lobe (5.2.3); The variable-diameter driving structure drives a plurality of variable-diameter wheel lobes (5.2.3) to synchronously extend outwards or contract inwards.

3. The tension-adjustable multi-degree-of-freedom multi-filament laying head according to claim 2, wherein The end surface of the variable-diameter wheel lobe (5.2.3) arranged along the axial direction of the ring is an axial end surface, and the axial end surfaces on both sides of each variable-diameter wheel lobe (5.2.3) are inclined surfaces and are symmetrically arranged with the radial shaft (5.2.2) as the axis of symmetry; The variable-diameter driving structure includes an extrusion disc (5.11), an extrusion cylinder (5.12), an extrusion cylinder support piece, and a guiding frame (5.13); Two extrusion discs (5.11) are installed on the driving wheel shaft (5.3) through keys and key grooves. The two extrusion discs (5.11) are located on both sides of the refeeding driving wheel (5.2). An extrusion surface is arranged on each extrusion disc (5.11), and the extrusion surface is attached to the axial end surface of the variable-diameter wheel lobe (5.2.3); The extrusion cylinder (5.12) is parallel to the driving wheel shaft (5.3); Two extrusion cylinder support plates are respectively connected to the corresponding extrusion disks (5.11) through thrust needle roller bearings (5.14). The two extrusion cylinder support plates are respectively an extrusion cylinder support plate Ⅰ (5.15) and an extrusion cylinder support plate Ⅱ (5.16). The extrusion cylinder support plate Ⅰ (5.15) is fixedly connected to the cylinder block of the extrusion cylinder (5.12), and the extrusion cylinder support plate Ⅱ (5.16) is fixedly connected to the telescopic rod of the extrusion cylinder (5.12). A guide hole is provided on the extrusion cylinder support plate Ⅱ (5.16). The guide frame (5.13) is fixedly connected to the refeeding frame (5.1). A guide shaft parallel to the driving wheel shaft (5.3) is provided on the guide frame (5.13), and the guide shaft passes through the guide hole.

4. The tension-adjustable multi-degree-of-freedom multi-filament laying head according to claim 1, wherein The compaction wheel (9.1) includes an outer wheel (9.1.1) made of spring steel, spring curved petals (9.1.2) and a hub (9.1.3). The outer wheel (9.1.1) and the hub (9.1.3) are concentrically arranged, and the outer wheel (9.1.1) is located outside the hub (9.1.3). The spring curved petals (9.1.2) are of a bent plate-like structure. The spring curved petals (9.1.2) are arranged between the outer wheel (9.1.1) and the hub (9.1.3). The inner end of the spring curved petals (9.1.2) is inserted into the hub (9.1.3), and the outer end of the spring curved petals (9.1.2) is welded to the outer wheel (9.1.1). The compaction wheel shaft is fixedly connected to the rear end of the swing frame (9.2) and is rotatably connected to the hub (9.1.3) of the compaction wheel (9.1) through a cylindrical roller bearing (9.5). The swing compaction mechanism (9) further includes a strain gauge type pressure sensor (9.7). The strain gauge type pressure sensor (9.7) is fixed on both sides of the swing frame (9.2) and is used to detect the force difference on both sides of the compaction wheel (9.1), providing a basis for adjusting the pressure of the compensation cylinder (9.3).

5. The tension-adjustable multi-degree-of-freedom multi-filament laying head according to any one of claims 1-4, characterized in that, Each unwinding mechanism (2) further includes sliding bearings arranged in sequence from the inside to the outside. The inner rings and outer rings of two adjacent sliding bearings are fixedly connected. Among two adjacent sliding bearings, both ends of the inner layer sliding bearing are located outside the ends of the outer layer sliding bearing. The inner ring of the innermost sliding bearing is fixedly connected to the frame (1). The unwinding wheel drive assembly includes an unwinding servo motor, an unwinding driving gear and an unwinding driven gear. An unwinding wheel and an unwinding driven gear are fixedly sleeved outside the outer ring of each sliding bearing. The unwinding driven gear meshes with the corresponding unwinding driving gear, and the unwinding driving gear is driven to rotate by the corresponding unwinding servo motor. The unwinding servo motors are all fixed on the frame (1).

6. The tension-adjustable multi-degree-of-freedom multi-filament laying head according to claim 5, characterized in that, The front guiding mechanism (4) includes a front guiding support frame (4.1), a conical guide wheel Ⅰ (4.2), a transition guide wheel (4.3) and a conical guide wheel Ⅱ (4.4). The front guiding support frame (4.1) is connected to the machine frame (1). A plurality of front guiding channels (4.5) are arranged side by side on the front guiding support frame (4.1). The number of the front guiding channels (4.5) corresponds to the number of unwinding wheels. Conical guide wheel shafts I, transition guide wheel shafts, and conical guide wheel shafts II are symmetrically arranged on both sides of the front guiding channel (4.5). The distances between the conical guide wheel shafts I, transition guide wheel shafts, and conical guide wheel shafts II and the front guiding channel (4.5) gradually decrease; The conical guide wheel I (4.2), the transition guide wheel (4.3), and the conical guide wheel II (4.4) are respectively installed on the conical guide wheel shafts I, transition guide wheel shafts, and conical guide wheel shafts II through self-aligning roller bearings (4.6). The distances between the conical guide wheel I (4.2), the transition guide wheel (4.3), the conical guide wheel II (4.4) and the front guiding channel (4.5) gradually decrease; The number of the conical guide wheel I (4.2), the number of the transition guide wheel (4.3), and the number of the conical guide wheel II (4.4) on the same side of the front guiding channel (4.5) respectively correspond to the number of unwinding wheels on one side of the machine frame (1). The taper angles of the conical guide wheel I (4.2) and the conical guide wheel II (4.4) on the same side of the front guiding channel (4.5) are opposite; The taper angles of the two groups of conical guide wheel I (4.2) on both sides of the front guiding channel (4.5) are opposite. The taper angles of the two groups of conical guide wheel II (4.4) on both sides of the front guiding channel (4.5) are opposite.

7. The tension-adjustable multi-degree-of-freedom multi-filament laying head according to claim 6, characterized in that, The shearing mechanism (6) includes a shearing frame (6.1), a tension sensor (6.2), a shearing cylinder (6.3), a tool holder (6.4), and a blade (6.5); The shearing frame (6.1) is fixedly connected to the machine frame (1). A plurality of independent wire feeding channels (6.6) are arranged side by side on the shearing frame (6.1). The number of the wire feeding channels (6.6) corresponds to the number of unwinding wheels. A tension sensor installation groove (6.7) and a shearing groove (6.8) are arranged on each wire feeding channel (6.6). The tension sensor installation groove (6.7) and the shearing groove (6.8) vertically penetrate the upper surface and the lower surface of the wire feeding channel (6.6). The lower surface of the wire feeding channel (6.6) is connected to the front surface and the rear surface of the tension sensor installation groove (6.7) through round corners respectively. The upper surface and the lower surface of the wire feeding channel (6.6) are respectively connected to the rear surface of the shearing groove (6.8) through chamfers; A tension sensor (6.2) is installed in the tension sensor installation groove (6.7) of each wire feeding channel (6.6). The variable-angle force measuring wheel of the tension sensor (6.2) is aligned with the lower surface of the wire feeding channel (6.6) in the initial state; A shearing cylinder (6.3) is installed above each wire feeding channel (6.6). The shearing cylinder (6.3) is connected to the blade (6.5) through a tool holder (6.4). The blade (6.5) is located above the shearing groove (6.8).

8. The tension-adjustable multi-degree-of-freedom multi-filament placement head according to claim 7, wherein A double center rotary table (1.1) and a winding post (1.2) are arranged on the machine frame (1); The double-center turntable (1.1) is parallel to the connection line of the centers of the two pay-off reels. A guiding groove (1.1.1) is provided on the lower surface of the double-center turntable (1.1), and the guiding groove (1.1.1) is parallel to the connection line of the centers of the two pay-off reels. Rotary grooves (1.1.2) are provided on both sides of the double-center turntable (1.1). The rotary groove (1.1.2) includes an inclined-plane groove and an arc groove located above the inclined-plane groove. The inclined-plane groove extends from the end of the double-center turntable (1.1) to the bottom end of the arc groove and the height gradually increases. A limiting groove (1.1.3) is provided in the rotary groove (1.1.2); Two winding columns (1.2) are symmetrically arranged on both sides of the guiding groove (1.1.1); The rear guiding mechanism (7) includes an end guide (7.1), a flexible guide rail (7.2), a double-center rotary support (7.3), a follow-up frame (7.4) and an elastic traction rope (7.5); The end guide (7.1) is an arc-shaped plate structure and is provided with a plurality of independent wire outlet channels (7.6). The number of the wire outlet channels (7.6) corresponds to the number of pay-off reels. The front ends of the plurality of wire outlet channels (7.6) are arranged side by side, and the rear ends of the plurality of wire outlet channels (7.6) are arranged staggered up and down. The end guide (7.1) is fixedly connected with the swing frame (9.2). The front end of the end guide (7.1) is connected with the rear end of the shearing frame (6.1) through the flexible guide rail (7.2). The rear end of the end guide (7.1) is tangent to the compaction wheel (9.1); A rear guiding channel communicating the wire feeding channel (6.6) and the wire outlet channel (7.6) is provided in the flexible guide rail (7.2); The double-center rotary support (7.3) includes a rotary cross beam (7.3.1), a rotary vertical beam (7.3.2), a connecting column (7.3.3) and a rotary column (7.3.4). The rotary vertical beam (7.3.2) is perpendicular to the rotary cross beam (7.3.1) and the top end thereof is connected with the central position of the rotary cross beam (7.3.1). The connecting column (7.3.3) is vertically connected with the bottom end of the rotary vertical beam (7.3.2) and is perpendicular to the rotary cross beam (7.3.1). Two rotary columns (7.3.4) are symmetrically arranged on both sides of the rotary vertical beam (7.3.2) and are vertically connected with the rotary cross beam (7.3.1). The rotary column (7.3.4) is perpendicular to the rotary vertical beam (7.3.2), and a limiting ring (7.3.5) is provided on the rotary column (7.3.4); The rotary cross beam (7.3.1) of the double-center rotary support (7.3) is fixedly connected with the central position of the lower surface of the flexible guide rail (7.2), and the connecting column (7.3.3) is inserted into the guiding groove (1.1.1) of the double-center turntable (1.1); The follow-up frame (7.4) includes a follow-up cross beam and a follow-up vertical beam. The follow-up cross beam is located above the machine frame (1), and a wiring column is provided at the central position of the follow-up cross beam. Two follow-up vertical beams are located on both sides of the machine frame (1) and the swing shaft. The top ends of the follow-up vertical beams are fixedly connected with the follow-up cross beam, and the bottom ends of the follow-up vertical beams are fixedly connected with the swing frame (9.2); The single-sided elastic traction rope (7.5) bypasses the wire winding column (1.2) and connects the connection column (7.3.3) of the double-center rotary support (7.3) and the wiring column of the follower frame (7.4); the elastic traction ropes (7.5) on both sides pull down the rotary columns (7.3.4) at both ends of the double-center rotary support (7.3) into the rotary grooves (1.1.2) on both sides of the double-center rotary table (1.1), and the limit ring (7.3.5) cooperates with the limit groove (1.1.3).

9. The tension-adjustable multi-degree-of-freedom multi-filament placement head according to claim 8, characterized in that, The number of unwinding wheels on one side of the machine frame (1) is two, namely unwinding wheel I (2.1) and unwinding wheel II (2.2); Each unwinding mechanism (2) includes two sliding bearings, namely sliding bearing I (2.3) and sliding bearing II (2.4), and sliding bearing I (2.3) is located outside sliding bearing II (2.4); An expansion sleeve I (2.5) and an unwinding driven gear I (2.6) are fixedly sleeved outside the outer ring of the sliding bearing I (2.3). The unwinding wheel I (2.1) is installed outside the expansion sleeve I (2.5), and the unwinding driven gear I (2.6) meshes with the corresponding unwinding driving gear I (2.7), and the unwinding driving gear I (2.7) is driven to rotate by the corresponding unwinding servo motor I (2.8); An expansion sleeve II (2.9) and an unwinding driven gear II (2.10) are fixedly sleeved outside the outer ring of the sliding bearing II (2.4). The unwinding wheel II (2.2) is installed outside the expansion sleeve II (2.9), and the unwinding driven gear II (2.10) meshes with the corresponding unwinding driving gear II (2.11), and the unwinding driving gear II (2.11) is driven to rotate by the corresponding unwinding servo motor II (2.12); In the front guiding mechanism (4), the number of conical guide wheels I (4.2), the number of transition guide wheels (4.3), and the number of conical guide wheels II (4.4) on the same side of the front guiding channel (4.5) are all two; In the refeeding mechanism (5), the number of refeeding modules is two, namely refeeding module I and refeeding module II. The single-strip prepreg refeeding areas of refeeding module I and refeeding module II are arranged in a staggered manner. The two driving wheel shafts (5.3) in refeeding module I are respectively driving wheel shaft Ia and driving wheel shaft Ib, and the two driving wheel shafts (5.3) in refeeding module II are respectively driving wheel shaft IIa and driving wheel shaft IIb; The refeeding drive assembly includes a refeeding servo motor (5.17), a refeeding gear I (5.18), a refeeding gear II (5.19), a pulley I (5.20), a synchronous belt I (5.21), a pulley II (5.22), a pulley III (5.23), a synchronous belt II (5.24), and a pulley IV (5.25); The refeeding servo motor (5.17) is fixed on the machine frame (1) and has a braking function. The output shaft of the refeeding servo motor (5.17) is connected to the pulley I (5.20); Two refeeding gears I (5.18) are respectively installed on the driving wheel shaft Ia and the driving wheel shaft Ib, and the two refeeding gears I (5.18) mesh with each other; Two re-feed gears II (5.19) are respectively installed on the driving wheel shaft IIa and the driving wheel shaft IIb, and the two re-feed gears II (5.19) are meshed with each other; The pulley II (5.22) and the pulley III (5.23) are respectively installed at both ends of the driving wheel shaft Ia. The pulley II (5.22) and the pulley I (5.20) are arranged on the same side and are connected by a synchronous belt I (5.21); The pulley IV (5.25) is installed on the driving wheel shaft IIa. The pulley IV (5.25) and the pulley III (5.23) are arranged on the same side and are connected by a synchronous belt II (5.24); The re-feed gear I (5.18) and the re-feed gear II (5.19) rotate at the same speed; The heating mechanism (8) includes a heating nozzle and a hot air gun. The heating nozzle is installed on the swing frame (9.2), and the hot air gun is connected to the heating nozzle.

10. A laying method, characterized in that, Laying is performed by using the multi-degree-of-freedom multi-filament laying head with adjustable tension described in claim 9, including the following steps: S1, Install the material roll on the unwinding wheel; S2, Pull out the prepreg tape from the material roll, successively bypass the conical guide wheel I (4.2), the transition guide wheel (4.3), the conical guide wheel II (4.4), and then pass through the front guiding channel (4.5) to reach the re-feed mechanism (5); S3, Cut off the power supply of the re-feed servo motor (5.17) or switch it to the free rotation mode, pass the prepreg tape through the single-strip prepreg re-feed area, and enter the front end of the wire feeding channel (6.6); S4, Lift the variable-angle force measuring wheel of the tension sensor (6.2) to make the prepreg tape pass through the tension sensor installation groove (6.7) until it exceeds the shear groove (6.8); S5, Switch the re-feed servo motor (5.17) to the braking state, clamp and fix the prepreg tape with the re-feed driving wheel (5.2) and the re-feed driven wheel (5.4), start the first shear cylinder (6.3) to perform the primary shearing on the end of the prepreg tape, and start the unwinding servo motor to output a constant torque in the reverse direction to apply tension to the prepreg tape between the unwinding mechanism (2) and the re-feed mechanism (5); S6, Move the multi-degree-of-freedom multi-filament laying head with adjustable tension to the starting point of the laying path, start the re-feed servo motor (5.17) to send the prepreg tape to the outlet of the end guide (7.1), at the same time start the compensation cylinder (9.3) to adjust the compaction wheel (9.1) to the preset angle, start the heating mechanism (8), and then the re-feed servo motor (5.17) continues to work to send the prepreg tape to the curved surface position of the compaction wheel (9.1), and start the compaction cylinder (3) to compact the end of the prepreg tape on the mandrel; S7. Lay according to the laying path. During the laying process, tension appears in the prepreg tape between the refeeding mechanism (5) and the mandrel. The refeeding servo motor (5.17) drives the driving wheel shaft (5.3) to rotate at the linear velocity of the moving speed of the center track of the compaction wheel (9.1). Adjust the extrusion cylinder (5.12) in real time according to the tension measured by the tension sensor (6.2) to change the diameter of the refeeding driving wheel (5.2) and then change the refeeding speed. If the tension is greater than the set value, increase the refeeding speed; if the tension is less than the set value, decrease the refeeding speed. Adjust the thrust of the compensation cylinder (9.3) through the strain gauge pressure sensors (9.7) fixed on both sides of the swing frame (9.2) to make the pressure on the compaction wheel (9.1) uniform. S8. When the distance between the multi-degree-of-freedom multi-filament laying head with adjustable tension and the end point of the laying path is equal to the length of the prepreg tape between the compaction wheel (9.1) and the blade (6.5), start the shearing cylinder (6.3) once to cut the prepreg tape. At the same time, switch the refeeding servo motor (5.17) to the braking state. The refeeding driving wheel (5.2) and the refeeding driven wheel (5.4) clamp and fix the uncut prepreg tape. The entire multi-degree-of-freedom multi-filament laying head with adjustable tension continues to move along the laying path to the end point, press the cut prepreg tape on the mandrel, complete this laying, turn off the heating mechanism (8), and lift the compaction cylinder (3). S9. If you want to continue the next laying, the multi-degree-of-freedom multi-filament laying head with adjustable tension moves to the starting point of the next laying path and repeats entering S6. If the laying is completed, first turn off the unwinding servo motor, then turn off the refeeding servo motor (5.17), move the multi-degree-of-freedom multi-filament laying head with adjustable tension to the starting position, cut off the power supply, and directly enter S5 when starting up next time. If the material roll on the unwinding wheel is used up, turn off the unwinding servo motor. The entire multi-degree-of-freedom multi-filament laying head with adjustable tension continues to move along the laying path, press the prepreg tape between the unwinding wheel and the compaction wheel on the mandrel, then turn off the refeeding servo motor (5.17), move the multi-degree-of-freedom multi-filament laying head with adjustable tension to the starting position, cut off the power supply, and enter S1 when starting up next time.

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