Flexible clamp for machining foam sandwich of control plane of unmanned aerial vehicle

Abstract

The invention relates to the technical field of unmanned aerial vehicle part machining, in particular to a flexible clamp for machining foam sandwich cores such as an unmanned aerial vehicle control surface, the flexible clamp comprises a supporting seat, a driving assembly and a universal positioning assembly, a plurality of mounting holes are formed in the supporting seat, and ejector rods are slidably arranged in the mounting holes through sealing structures; a spring is arranged between the lower portion of the ejector rod and the inner bottom face of the guide hole, a suction cup is arranged at the top of the ejector rod, an air channel is coaxially formed in the ejector rod, one port of the air channel is connected with the suction cup, the other port of the air channel is communicated with a vacuum air channel formed in the supporting base, and an inlet of the vacuum air channel is used for being connected with a vacuum pump. Every two rows of ejector rods form an ejector rod set. A clamping part is arranged in a guide hole formed in the supporting seat between every two ejector rod groups; the driving assembly is used for driving the clamping part to synchronously lock the ejector rods in each ejector rod group; and the universal positioning assembly is used for positioning the foam sandwich. According to the device, material waste is reduced, and the clamping and positioning precision is improved.

Description

Technical Field

[0001] This invention relates to the field of UAV component processing technology, specifically a flexible fixture and clamping and positioning method for processing UAV control surface foam cores. It is applicable to the flipping processing of UAV control surface foam cores and other parts, and can reliably meet the production requirement of foam core processing accuracy ≤0.3mm. Background Technology

[0002] In the production of foam sandwich parts such as drone control surfaces, traditional dedicated fixtures have the following significant drawbacks: each type of control surface requires a separate fixture, and old fixtures are basically scrapped when products are iterated or changed, resulting in a material waste rate of over 60%, and fixture costs account for more than 25% of the total part processing cost; the cross-model reuse rate is less than 5%, leading to a backlog of fixture inventory and occupying warehouse space; and traditional fixtures mostly fix parts using pressure plates or other fixing methods, which are limited and inefficient for mass production, and cannot fully process foam products, and are subject to interference from the table and pressure plates.

[0003] Therefore, there is a need to provide a flexible fixture for processing foam cores for UAV control surfaces to solve the above problems. Summary of the Invention

[0004] This invention provides a flexible fixture for processing foam cores for unmanned aerial vehicle (UAV) control surfaces, in order to solve existing problems.

[0005] The first aspect of this invention provides a flexible fixture for processing foam cores for unmanned aerial vehicle (UAV) control surfaces. This flexible fixture employs the following technical solution, including: The support base has multiple vertically arranged mounting holes evenly distributed on it. A push rod is slidably installed in the mounting holes through a sealing structure. A spring is installed between the limiting platform at the lower part of the push rod and the inner bottom surface of the guide hole. A suction cup is installed at the top of the push rod. An air passage is coaxially arranged inside the push rod. One end of the air passage is connected to the suction cup, and the other end of the air passage is connected to a vacuum passage on the support base. The inlet of the vacuum passage is used to connect to a vacuum pump. Each two rows of push rods form a push rod group. The clamping part is provided in the guide hole provided on the support seat between each push rod group, and each guide hole corresponds to the push rod of each push rod group; A drive assembly is used to drive the clamping part to synchronously lock the push rods in each push rod group; And a universal positioning component for positioning the foam core.

[0006] A further technical solution of the present invention is that the driving component includes: The drive shaft is horizontally slidably disposed in the support seat between the two rows of push rods in each push rod group. One end of the drive shaft is located in the support seat, and the other end of the drive shaft extends out of the support seat. Multiple wedge-shaped transmission blocks are evenly distributed on the transmission shaft, and each wedge-shaped transmission block is located between the clamping parts of every two opposing push rods in each push rod group; A reset assembly, used for resetting the drive shaft; And a nut screw drive component, which is located at one end of the drive shaft extending from the support seat, is used to drive the drive shaft to move so that the wedge-shaped drive block drives the clamping part to move along the guide hole to clamp the push rod.

[0007] A further technical solution of the present invention is that the wedge-shaped transmission block on the transmission shaft is horizontally slidably disposed in the transmission hole provided on the support base, and the two ends of the transmission hole are provided with guide through holes. The transmission hole and the two guide through holes are connected to form the active cavity of the drive assembly, wherein the diameter of the guide through hole is smaller than the diameter of the transmission hole.

[0008] A further technical solution of the present invention is that the wedge-shaped transmission block is a frustum, the large end face of the frustum faces the nut screw drive component, and the outer peripheral surface of the frustum and the end of the clamping part slide in contact.

[0009] A further technical solution of the present invention is that two guide blocks are provided on the transmission shaft, and the guide blocks cooperate with the corresponding guide through holes.

[0010] A further technical solution of the present invention is that the reset assembly includes a reset spring, which is disposed on a transmission shaft between one of the guide blocks and the bottom surface of the guide through hole.

[0011] A further technical solution of the present invention is that an air nozzle is provided at the inlet of the vacuum passage.

[0012] A further technical solution of the present invention is that the universal positioning assembly includes: a connecting rod, which is horizontally connected to one side of the support base, and a support rod on which a vertical connecting rod is connected via a first universal ball joint, and a positioning rod on which a second universal ball joint is connected.

[0013] A further technical solution of the present invention is that a vacuum logic valve is provided in the air passage, which is used to automatically control the opening and closing of the air passage according to the contact pressure between the push rod and the foam core.

[0014] The second aspect of this invention provides a method for processing and positioning foam cores for UAV control surfaces. This method utilizes a flexible fixture for processing foam cores for UAV control surfaces, as provided in the first aspect of this invention, to process and position the foam cores, including control surfaces. The processing and positioning steps are as follows: Place the foam core of the rudder surface to be processed onto the suction cup on the top rod of the flexible fixture; The control machine screw drive component rotates to drive the transmission shaft to rotate and advance axially until the wedge-shaped surface of the wedge-shaped transmission block on the transmission shaft pushes the clamping column to tighten the push rod, that is, to lock the position of the push rod. A vacuum pump is used to remove air from the suction cup, creating a vacuum environment between the suction cup and the bonding surface of the foam core to be processed. The suction cup generates an adsorption force under the action of air pressure difference, thus achieving the adsorption of the foam core to be processed. The fixture is mounted on the worktable of the CNC milling machine for machining.

[0015] The beneficial effects of this invention are: Compared with traditional fixtures and other fixtures, this invention not only has the advantages of traditional fixtures such as compact structure, quick and convenient operation, and labor saving, but also the advantages of adjustable fixtures and group fixtures such as flexibility, versatility, short manufacturing cycle, reusable components, and wide applicability. It can ensure the stability and accuracy of workpieces during processing and can quickly position them, thereby improving production efficiency, product quality and reducing labor costs.

[0016] The specific effects are as follows: Cost reduction and consumption reduction: Compatible with over 90% of rudder surface models, with a reuse rate of ≥90%, reducing material waste rate from 60% to 10%. Efficiency and speed improvement: Mold making cycle reduced from 3-5 days to 0.5 days, single-set processing time reduced from 60 minutes to 40 minutes, increasing efficiency by 30%; scrap rate reduced from 15% to 3%. Stable precision: Wedge locking (deviation ≤0.1mm), universal positioning (deviation ≤0.1mm), and vacuum adsorption (force ≥20N), the fixture achieves a part repositioning accuracy ≤0.2mm in batch production, meeting the process requirement of processing accuracy ≤0.3mm. Convenient operation: Can be handled by a single person (≤8kg), machine tool installation ≤5 minutes, reducing labor intensity. Durable and reliable: Key components use high-strength materials, leak-proof sealing rings, and a service life ≥5 years, exceeding the 3-year lifespan of traditional fixtures. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a flexible fixture for processing foam cores for unmanned aerial vehicle control surfaces according to the present invention; Figure 2 for Figure 1 Top view; Figure 3 This is a first cross-sectional view of a flexible fixture for processing foam cores for unmanned aerial vehicle control surfaces according to the present invention. Figure 4 for Figure 1 A schematic diagram of the structure of the push rod, suction cup, air passage, vacuum logic valve, sealing ring and suction port; Figure 5 for Figure 1 A schematic diagram showing the engagement of the drive assembly, clamping column, and push rod. Figure 6 for Figure 5 A partial schematic diagram of the driving component; Figure 7 This is a schematic diagram of the cavity on the support base; Figure 8 This is a schematic diagram of the distribution of vacuum channels; Figure 9 This is a schematic diagram of the finished foam sandwich part in an embodiment of the present invention; Figure 10 This is a second cross-sectional view of a flexible fixture for processing foam cores for unmanned aerial vehicle control surfaces according to the present invention.

[0019] In the diagram: 1. Top rod; 2. Suction cup; 3. Clamping column; 4. Spring; 5. Vacuum logic valve; 6. Sealing ring; 7. Suction port; 8. Air passage; 9. Handle; 10. Universal positioning assembly; 11. Air nozzle; 12. Vacuum passage; 13. Transmission hole; 14. Guide through hole; 15. Mechanism screw drive component; 16. Guide block; 17. Return spring; 18. Locking screw; 19. Wedge-shaped transmission block; 20. Transmission shaft; 21. Clamping and fixing step; 22. Support base. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] An embodiment of the flexible clamp for processing foam cores for unmanned aerial vehicle (UAV) control surfaces according to the present invention is as follows: Figure 1 and Figure 2 As shown, it includes: a support base 22, a clamping part, a drive assembly, and a universal positioning assembly. The support base 22 has multiple vertically arranged mounting holes evenly distributed on it. A push rod 1 is slidably disposed within each mounting hole via a sealing structure. Figure 3 , Figure 4 and Figure 10As shown, a spring 4 is installed between the limiting platform at the lower part of the push rod 1 and the inner bottom surface of the guide hole. It should be noted that the mounting hole is a stepped hole, with the upper diameter smaller than the lower diameter. This allows the limiting platform to press against the stepped surface of the stepped hole under the spring force, thus limiting the movement. That is, when no product with clamping is placed on the push rod 1, the elastic force of the spring 4 keeps all the push rods 1 on the same horizontal plane. A suction cup 2 is installed at the top of the push rod 1. An air passage 8 is coaxially arranged inside the push rod 1. One port of the air passage 8 is connected to the suction cup 2, and the other port of the air passage 8 is connected to a vacuum passage 12 on the support base 22. The inlet of the vacuum passage 12 is used to connect to a vacuum pump. Figure 8 As shown, the mounting holes of each row of top rods 1 are connected to a vacuum channel 12. The vacuum channels 12 corresponding to all rows of top rods 1 are connected in parallel and then extend to the outside of the support base 22 through a total vacuum channel 12 and connect to the air nozzle 11. Each two rows of top rods 1 form a top rod group. The clamping part is set in the guide hole provided on the support base 22 between each top rod group, and each guide hole corresponds one-to-one with the top rod of each top rod group. The driving component is used to drive the clamping part to lock the top rod in each top rod group synchronously. The universal positioning component 10 is used to position the foam core. For example, in a specific embodiment, a vacuum logic valve 5 is provided in the air channel 8. The vacuum logic valve 5 is used to automatically control the opening and closing of the air channel 8 according to the contact pressure between the top rod 1 and the foam core.

[0022] It should be noted that in this embodiment, the support base 22 is made of aerospace-grade 6061-T6 aluminum alloy, with a tensile strength ≥310MPa, a yield strength ≥276MPa, and an overall weight ≤8kg (standard specifications), which is 40%-50% lighter than traditional cast iron clamps; and the surface of the support base 22 is anodized (film thickness 10-15μm), achieving a rust prevention level of Grade 9 in GB / T 10125-2021; Figure 1 , Figure 2 and Figure 8As shown, multiple push rods 1 are arranged in a matrix array (25mm spacing). Push rods 1 are made of TC4 titanium alloy, with a diameter of 10mm, a length of 65mm, a tensile strength ≥860MPa, and a yield strength ≥825MPa. The ends of push rods 1 are made of hemispherical rubber; the hemispherical design is intended to adapt to the shape of the control surface, achieving seamless force application. The springs 4 on the push rods 1 are made of 50CrVA material, with a diameter of 10mm, a free length of 100mm, and an elastic modulus of 5-30N / mm. They are normally extended, with an extension height deviation ≤0.1. The axial adjustment range is 0-60mm, and the adjustment accuracy is ≤0.08mm. A sealing structure is provided between the top port of the mounting hole of the push rod 1 and the support seat 22. The sealing structure is a sealing ring 6, which is made of nitrile rubber (model O-ring, inner diameter 10mm, wire diameter 2mm, hardness 70A), with a sealing rating of IP65, to prevent air leakage in the air passage 8 and to stop dust. The vacuum logic valve is a built-in KVL200 type (response time ≤0.5s), and the valve body is made of POM plastic. The melting point of POM plastic is 175℃, the tensile strength is ≥60MPa, and the leakage rate of the non-working contact push rod 1 is ≤4%. The suction cup 2 is made of food-grade silicone material. The Shore hardness of food-grade silicone material is 35A, the tensile strength is ≥8MPa, the tear strength is ≥25kN / m, the diameter is 12mm, and it is normally 5mm ±0.2mm higher than the push rod 1. The adsorption force is ≥20N under a vacuum of -0.08MPa and it is compatible with ±8° surface tilt. Furthermore, in this embodiment, a polyurethane foam ring is fitted at the connection between the suction cup 2 and the push rod 1. The polyurethane foam ring has a thickness of 4mm, a porosity of 65%, a density of 30kg / m³, and a dust blocking rate of ≥90%. Four 3mm diameter suction holes 7 are evenly distributed on the side of the end of the push rod 1, with an included angle of 90° between adjacent suction holes 7 and an air pressure distribution deviation of ≤0.02MPa. The suction holes 7 are used to connect the air passage 8 and the suction cup 2. For example, as shown... Figure 3 and Figure 10 As shown, in one specific embodiment, a horizontally arranged vacuum passage 12 is provided at the lower part of the support base 22. One port of the vacuum passage 12 is provided with an air nozzle 11, and the other port of the vacuum passage 12 is connected to the mounting holes of all the top rods 1. The diameter of the vacuum passage 12 is 8mm, the surface roughness Ra≤1.6μm, and the air tightness leakage rate≤3% / h (at 0.8MPa). The air nozzle 11 is made of G1 / 4 304 stainless steel and has a pressure resistance ≥1.6MPa. Two pipes are connected in parallel on the air nozzle 11. One pipe is used to connect an external vacuum pump, and the other pipe is equipped with a pressure gauge.

[0023] For example, such as Figure 5 , Figure 6 as well as Figure 10As shown, in one specific embodiment, the drive assembly includes: a drive shaft 20, a reset assembly, and a grommet screw drive 15. The drive shaft 20 is horizontally slidably disposed within a support seat 22 between two rows of push rods 1 in each push rod group. One end of the drive shaft 20 is located within the support seat 22, and the other end extends out of the support seat 22. Multiple wedge-shaped transmission blocks 19 are evenly distributed on the drive shaft 20, and each wedge-shaped transmission block 19 is disposed between the clamping portions of every two opposing push rods 1 in each push rod group. The reset assembly is used to reset the drive shaft 20. The grommet screw drive 15 is disposed at the end of the drive shaft 20 extending out of the support seat 22, and the grommet screw drive 15 is used to drive the drive shaft 20 to move so that the wedge-shaped transmission blocks 19 drive the clamping portions to move along the guide holes, thereby clamping the push rods. Wherein, as... Figure 7 As shown, in this embodiment, the wedge-shaped transmission block 19 on the transmission shaft 20 is horizontally slidably disposed within the transmission hole 13 provided on the support base 22. Guide through holes 14 are provided at both ends of the transmission hole 13. The transmission hole 13 and the two guide through holes 14 communicate to form the movable cavity of the drive assembly. The diameter of the guide through holes 14 is smaller than the diameter of the transmission hole 13. In this embodiment, the wedge-shaped transmission block 19 is a frustum, with the large end face of the frustum facing the mechanic screw drive member 15, and the outer peripheral surface of the frustum slidingly contacting the end of the clamping part. In this embodiment, the transmission shaft 20 is provided with two guide blocks 16, which cooperate with corresponding guide through holes 14. In this embodiment, the reset assembly includes a reset spring 17, which is disposed on the transmission shaft 20 between one of the guide blocks 16 and the bottom surface of the guide through hole 14.

[0024] like Figure 7As shown, it should be noted that the cone angle of the frustum is 17°, and the wedge-shaped transmission block 19 is made of nylon (polyamide PA6). The cone surface of the frustum matches the end face of the clamping column 3 to ensure maximum clamping force. Each set of wedge-shaped transmission blocks 19 and clamping columns 3 is distributed to form a set of wedge-shaped components. A return spring 17 is installed on the transmission shaft 20 between the guide block 16 on the side opposite to the nut screw drive 15 and the bottom surface of the guide through hole. The return spring 17 is a 65Mn spring (diameter 6mm, free length 20mm, elastic coefficient 10N / mm), used to pop the transmission shaft 20 back after the nut screw drive 15 is released, thereby ensuring that the clamping column 3 is normally popped out. When the nut screw drive 15 drives the transmission shaft 20, the guide block 16 ensures that all the wedge-shaped transmission blocks 19 do not rotate or deviate, ensuring the clamping force in the correct direction. The wedge-shaped transmission blocks 19 are fixed to the transmission shaft 20 by locking screws 18 for easy replacement and adjustment. Secondly, in this embodiment, the grommet screw drive component 15 uses an M8×20mm grommet screw, which is made of 304 stainless steel (tensile strength ≥515MPa, thread accuracy 6H). It is equipped with a 304 stainless steel anti-slip self-locking knob (diameter 30mm, knurled surface). Turning it clockwise 2 turns locks it in place, and turning it counterclockwise 1 turn loosens it. A single operation takes ≤10 seconds.

[0025] For example, in one specific embodiment, the universal positioning assembly 10 includes: a connecting rod, which is horizontally connected to one side of the support base 22, and a support rod with a vertical connecting rod connected to it via a first universal ball joint, and a positioning rod connected to the support rod via a second universal ball joint; wherein, this embodiment includes two sets of universal positioning assemblies 10, each set of universal positioning assemblies 10 includes two universal positioning assemblies 10, and the two sets of universal positioning assemblies 10 are correspondingly arranged on adjacent side end faces of the support base 22. Specifically, in this embodiment, both the first universal ball joint and the second universal ball joint adopt bearing steel ball joint (diameter 10mm, hardness HRC58-62), rod length 120mm, adjustment angle 0°-90° (accuracy ≤0.5°), and repositioning accuracy ≤0.1mm.

[0026] In addition, handles 9 are provided on the corresponding sides of the support base 22. The handles 9 are made of 304 stainless steel, with a diameter of 28mm, a length of 100mm, and a tensile strength of ≥515MPa. The surface of the handles 9 is covered with a silicone anti-slip sleeve (thickness 3mm, Shore hardness 50A), allowing for single-person lifting. The bottom of the support base 22 has integrally formed 20mm×30mm clamping and fixing steps 21 (flatness ≤0.05mm) around its perimeter. The clamping and fixing steps 21 are used to adapt to the T-slot of the machine tool and are fixed in the T-slot of the machine tool with M10 bolts.

[0027] by Figure 9Taking the processing of aileron control surface foam core of a certain type of UAV as an example (it can also be a door panel type foam core), the steps of clamping the control surface foam core using the fixture of the present invention are as follows: Step 1, Fixture Adaptation Stage: First, based on the surface parameters of the foam core to be processed (UAV aileron control surface chord length 180mm, thickness 20mm, trailing edge inclination 10°), since the product is not placed on the fixture, the spring 4 at the lower end of the push rod 1 is in a naturally extended state. With the elastic coefficient of spring 4 of 8N / mm, the push rod 1 is pushed out normally. When the foam core sample is placed stably on the suction cup 2 at the top of the push rod 1 of the fixture, the suction cup 2 at the top of the push rod 1 first contacts the bottom surface of the foam core to be processed. As the foam core to be processed is pressed down, the push rod 1 in contact with the foam core to be processed compresses the spring 4 axially, while the push rod 1 not in contact with the foam core to be processed maintains the original ejection height. Finally, all the ends of the push rods 1 in contact automatically fit the surface of the foam core to be processed, so that the push rod 1 of the fixture forms a support matrix that is completely adapted to the surface of the foam core to be processed. The entire adaptation process requires no additional special mold processing and can be completed in just 2 minutes. Furthermore, the axial adjustment accuracy of the push rod 1 is ≤0.08mm, laying the foundation for subsequent processing accuracy of ≤0.3mm.

[0028] Step 2, Preliminary Positioning Stage: After adaptation, adjust the universal positioning components 10 on both sides of the fixture: using the multi-angle adjustment function of the ball joints of the first and second universal balls (accuracy ≤0.5° within the range of 0°-90°), rotate the positioning rod to make it fit against the edge reference surface of the foam core, and then lock the universal positioning components 10 to fix the angle. The two sets of universal positioning components 10 form a bidirectional reference constraint, ensuring that the initial position deviation of the foam core on the fixture is ≤0.1mm, avoiding edge offset during processing.

[0029] Step 3, Top Rod Locking Stage Rotating the grommet screw drive 15 on the side of the fixture clockwise drives the transmission shaft 20 axially, pushing the wedge-shaped transmission block 19 to move. The wedge-shaped surface of the wedge-shaped transmission block 19 and the clamping column 3 fit together, causing the clamping column 3 to extend along the guide hole and press against the outer circumferential surface of the push rod 1. At this time, the grommet screw drive 15 stops rotating (about 2 turns), forming a side-locking effect. The self-locking knob of the grommet screw drive 15 under the plate can firmly lock the transmission shaft 20, thus achieving the position locking of the push rod 1. The position deviation of the push rod 1 is ≤0.1mm. At the same time, the rubber ring 6 at the contact point between the push rod 1 and the upper surface of the support seat 22 is slightly compressed, forming an IP65-level seal, blocking the gap between the air passage 8 and the outside world, and preventing air leakage during subsequent vacuum adsorption. During this process, the return spring 17 on the transmission shaft 20 is compressed and stores elastic potential energy, preparing for subsequent reset.

[0030] Step 4, Vacuum Adsorption Stage: Connect the air hose of the external vacuum pump (vacuum range -0.06~-0.1MPa) to the G1 / 4 air nozzle 11 on the outside of the fixture. After turning on the vacuum pump, the airflow is delivered through the 8mm diameter vacuum channel 12 at the bottom of the fixture to the vacuum logic valve 5 in the air channel 8 inside each push rod 1. With a response speed of ≤0.5s, the vacuum logic valve 5 automatically detects the contact status between the push rod 1 and the foam core: the vacuum logic valve 5 in the push rod 1 in contact with the foam keeps the vacuum passage unobstructed, the air in the suction cup 2 is drawn away, forming a vacuum environment of about -0.08MPa. Under the action of the air pressure difference, the suction cup 2 generates an adsorption force of ≥20N, tightly adhering to the foam surface; the vacuum logic valve 5 in the push rod 1 that is not in contact with the foam automatically cuts off the passage, with a leakage rate of ≤5%, avoiding a decrease in the overall vacuum level. Meanwhile, the four 2.5mm air extraction holes 7 (with an adjacent angle of 90°) on the side of the head of the top rod 1 ensure that the air pressure in the suction cup 2 is evenly distributed with a deviation of ≤0.02MPa, preventing the foam core from deforming due to uneven local pressure (deformation ≤0.05mm).

[0031] Step 5, Processing and Fixing Stage: Hold the handles 9 on both sides of the fixture with both hands (a single person can easily lift a fixture weighing ≤8kg). Align the 20mm×30mm clamping and fixing step 21 at the bottom of the fixture with the T-slot (14-18mm wide) on the CNC milling machine table. Tighten the fixture with four sets of M10 bolts through the fixing holes of the clamping and fixing step 21 to complete the clamping (time ≤5 minutes). After clamping, check the flatness of the fixture table surface with a dial indicator. The deviation should be ≤0.05mm to ensure the stability of the machining datum. When starting the milling machine for flipping machining (such as milling the rear edge bevel of the foam core), the locking force formed by the drive assembly and clamping part, the adsorption force of the vacuum adsorption, and the positioning force of the universal positioning assembly 10 form a triple guarantee. The foam core does not shake, and the workpiece will not be scrapped due to component displacement during milling, reducing the scrap rate to below 3%.

[0032] Step 6, Unloading and Changing Stage: After processing, first turn off the vacuum pump and disconnect the air pipe. The suction cup 2 will return to normal pressure, and the suction force will disappear. Then, rotate the knob of the metric screw drive component 15 counterclockwise (about 1 turn). Under the elastic potential energy of the return spring 17, the drive shaft 22 will pop out and reset within 2 seconds, releasing the lock on the push rod 1. Then, release the universal positioning component 10 and adjust the positioning rod angle of the universal positioning component 10 to remove the processed foam core (unloading time ≤ 1 minute). If it is necessary to switch to another model (such as a horizontal tail rudder surface with a chord length of 200mm), there is no need to change the fixture body. Just repeat the steps of "mold adaptation - preliminary positioning - push rod locking - vacuum adsorption". The changeover time is ≤ 5 minutes, realizing flexible processing and production of multiple models.

[0033] Fixture maintenance: Routine maintenance (daily): Blow compressed air (0.4MPa) to clean the surface and nozzle; check suction cup (no damage), sealing ring (no deformation), and sponge ring (no blockage); test vacuum adsorption (standard test block adsorption without falling off) and wedge locking reset (no jamming).

[0034] Regular maintenance (monthly): Disassemble the top rod and check spring 4 (compression 10mm, spring force ≥30N, otherwise replace); clean the vacuum logic valve filter screen; check the sealing ring 6 for sealing performance, replace if leakage occurs.

[0035] Quarterly maintenance: Check the air tightness of air passage 8 (pressure drop ≤ 0.024MPa after 30 minutes at 0.8MPa); check the handle weld (no looseness); lubricate the universal ball joint of universal positioning assembly 10.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A flexible fixture for processing foam cores for unmanned aerial vehicle (UAV) control surfaces, characterized in that, include: The support base has multiple vertically arranged mounting holes evenly distributed on it. A push rod is slidably installed in the mounting holes through a sealing structure. A spring is installed between the limiting platform at the lower part of the push rod and the inner bottom surface of the guide hole. A suction cup is installed at the top of the push rod. An air passage is coaxially arranged inside the push rod. One end of the air passage is connected to the suction cup, and the other end of the air passage is connected to a vacuum passage on the support base. The inlet of the vacuum passage is used to connect to a vacuum pump. Each two rows of push rods form a push rod group. The clamping part is provided in the guide hole provided on the support seat between each push rod group, and each guide hole corresponds to the push rod of each push rod group; A drive assembly is used to drive the clamping part to synchronously lock the push rods in each push rod group; And a universal positioning component for positioning the foam core.

2. The flexible fixture for processing foam cores for UAV control surfaces according to claim 1, characterized in that, The driver components include: The drive shaft is horizontally slidably disposed in the support seat between the two rows of push rods in each push rod group. One end of the drive shaft is located in the support seat, and the other end of the drive shaft extends out of the support seat. Multiple wedge-shaped transmission blocks are evenly distributed on the transmission shaft, and each wedge-shaped transmission block is located between the clamping parts of every two opposing push rods 1 in each push rod group; A reset assembly, used for resetting the drive shaft; And a nut screw drive component, which is located at one end of the drive shaft extending from the support seat, is used to drive the drive shaft to move so that the wedge-shaped drive block drives the clamping part to move along the guide hole to clamp the push rod.

3. The flexible fixture for processing foam cores for UAV control surfaces according to claim 2, characterized in that, The wedge-shaped transmission block on the transmission shaft is horizontally slidably disposed in the transmission hole provided on the support base. Guide through holes are provided at both ends of the transmission hole. The transmission hole and the two guide through holes are connected to form the movable cavity of the drive assembly. The diameter of the guide through holes is smaller than the diameter of the transmission hole.

4. The flexible fixture for processing foam cores for UAV control surfaces according to claim 2, characterized in that, The wedge-shaped transmission block is a frustum, with the large end face of the frustum facing the nut screw drive component, and the outer peripheral surface of the frustum and the end of the clamping part making sliding contact.

5. A flexible fixture for processing foam cores for UAV control surfaces according to claim 2, characterized in that, Two guide blocks are provided on the drive shaft, and the guide blocks are engaged with corresponding guide holes.

6. A flexible fixture for processing foam cores for UAV control surfaces according to claim 5, characterized in that, The reset assembly includes a reset spring, which is disposed on a drive shaft between one of the guide blocks and the bottom surface of the guide through hole.

7. A flexible fixture for processing foam cores for UAV control surfaces according to claim 1, characterized in that, The vacuum duct inlet is equipped with an air nozzle.

8. A flexible fixture for processing foam cores for UAV control surfaces according to claim 1, characterized in that, The universal positioning assembly includes: a connecting rod, which is horizontally connected to one side of the support base, and a support rod to which a vertical connecting rod is connected via a first universal ball joint, and a positioning rod to which a second universal ball joint is connected.

9. A flexible fixture for processing foam cores for UAV control surfaces according to claim 1, characterized in that, A vacuum logic valve is installed inside the air passage. The vacuum logic valve is used to automatically control the opening and closing of the air passage based on the contact pressure between the push rod and the foam core.

10. A method for processing and positioning foam cores for unmanned aerial vehicle (UAV) control surfaces, characterized in that, The processing and positioning are performed using a flexible fixture for processing foam cores for UAV control surfaces, as described in any one of claims 1-9. The processing and positioning steps are as follows: Place the foam core of the rudder surface to be processed onto the suction cup on the top rod of the flexible fixture; The control machine screw drive component rotates to drive the transmission shaft to rotate and advance axially until the wedge-shaped surface of the wedge-shaped transmission block on the transmission shaft pushes the clamping column to tighten the push rod, that is, to lock the position of the push rod. A vacuum pump is used to remove air from the suction cup, creating a vacuum environment between the suction cup and the bonding surface of the foam core to be processed. The suction cup generates an adsorption force under the action of air pressure difference, thus achieving the adsorption of the foam core to be processed. The fixture is mounted on the worktable of the CNC milling machine for machining.

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