Aircraft composite structure dressing device and method

Abstract

The application discloses a kind of grinding device and method for aircraft composite material structure, according to the complex spatial surface of aircraft damaged area, the curved surface grinding head that is completely fitted with it is formed on site, without three-dimensional scanning and the process and structural parameters of aircraft composite material component, layer-by-layer grinding work is completed according to preset grinding interval quickly, accurately and with high precision, and the adjacent composite material structure layer that does not need to be ground is not damaged, and the grinding amount of damaged area is accurately fed back, which provides key data for patch production and the remaining strength and life assessment of aircraft composite material component.

Description

Technical Field

[0001] This invention belongs to the field of composite material grinding technology, specifically relating to a grinding device and method for aircraft composite material structures. Background Technology

[0002] Composite materials, due to their advantages such as high specific strength, high specific stiffness, vibration resistance, fatigue resistance, damage resistance, heat resistance, and good molding processability, have been increasingly widely used in modern aerospace structures. Especially since the beginning of the 21st century, with the gradual maturation of manufacturing processes and strength analysis techniques, the application of composite materials in the main load-bearing structures of aircraft (such as wings and fuselages) has made rapid progress. Although composite materials have many advantages and are widely used, in actual manufacturing processes, due to the influence of various factors such as process variations, temperature, and humidity, as well as the significant amount of human intervention involved, various manufacturing defects are inevitable in aircraft composite components, such as fiber breakage, delamination, and tearing. At the same time, during operation, aircraft wings or fuselages are also susceptible to impact damage, such as accidental tool drops during production or maintenance; impacts from small stones and other debris kicked up from the runway during takeoff and landing; and hail impacts when the aircraft is in the air or parked on the ground. Unlike traditional metallic materials, composite materials are defect-sensitive. They struggle to redistribute high-gradient stresses near defective or damaged areas through plastic deformation. Therefore, manufacturing defects and impact damage in composite materials can significantly reduce the load-bearing capacity and service life of aircraft structures, posing a serious threat to their safe operation. As required by airworthiness regulations, areas with such manufacturing defects or impact damage (hereinafter referred to as damaged areas) need to be ground and repaired using patch panels. However, for components with complex spatial curved surfaces, especially wings or fuselages with large curved areas, accurately and simply performing layer-by-layer grinding under limited conditions and feeding back relevant parameters is crucial for fabricating patch panels and reassessing the strength and service life of aircraft components using numerical simulation technology. Existing technologies cannot solve this problem and have several drawbacks.

[0003] 1) Poor surface fit and low precision. This is mainly reflected in two aspects: Firstly, although existing grinding heads use floating constant force devices to allow them to float up and down with the surface changes while maintaining a constant grinding force, the shape of the grinding head is still planar. Furthermore, composite material components are interlayer structures formed by layering and curing on a mold. Therefore, for curved surfaces with complex spatial characteristics, these planar grinding heads cannot closely fit the surface to grind layer by layer according to the defined grinding intervals, accurately removing damaged layers. Moreover, during the grinding process, it is easy to damage intact layers or expand the predetermined grinding area, or even penetrate the material. Even measures such as reducing the geometric size of the grinding head or weaving complex grinding paths cannot avoid these problems and reduce grinding efficiency. Secondly, existing technologies use dot-matrix flexible grinding heads to grind composite material components. Although this allows for better fit to the curved surface of the component, it cannot accurately reflect the grinding amount. This type of equipment is only suitable for manual rough grinding of composite material blanks.

[0004] 2) The equipment is complex, costly, and has limited use and high operational difficulty. Existing technology uses robots (or other multi-axis drive devices) combined with 3D scanning systems and intelligent control technology to scan the damaged area, obtain surface data of the area, import it into specialized software to generate accurate grinding paths, thereby achieving precise grinding of composite material components and providing relevant data feedback (laser grinding heads can achieve precise grinding, while surface grinding heads cannot). Obviously, this type of equipment has a complex structure and composition, high cost, and requires professional personnel to operate. At the same time, the conditions for using this type of equipment are also limited: for example, for large passenger aircraft, if the damaged area is located in a high place (such as the fuselage back or the top of the vertical tail) or in a space-constrained area, a platform and special tooling must be built to use it, or it may not be usable at all; for general aviation aircraft or helicopters operating in the field, the conditions for operating such complex equipment on site may not be available; etc. Therefore, this type of equipment is more suitable for grinding composite material components in laboratories or large aircraft production workshops, especially large-area blanks. 3) It poses adverse safety risks and has poor versatility. Current technologies using lasers for material removal and polishing can meet precision requirements, but lasers can also cause adverse effects on composite materials, such as delamination, fuzzing, and heat-affected zones. These adverse effects require subsequent reassessment of their impact on the structural safety of the composite material. While these adverse effects can be reduced, they are not unavoidable. To minimize the adverse effects of laser polishing of composite materials, repeated testing on composite material specimens with similar or identical structures, materials, and processes to aircraft is necessary to determine suitable parameters such as laser power, frequency, and deflection angle. Summary of the Invention

[0005] The purpose of this invention is to provide a grinding device and method for aircraft composite material structures, which solves the following problems: how to provide a grinding method and device that is simple in structure, lightweight, low in cost, easy to assemble and disassemble, simple to operate, and highly versatile, considering the curved geometric features, material structural properties, spatial location, and on-site constraints of the damaged area of ​​the aircraft composite material structure. This method can form a grinding head that perfectly fits the complex spatial curved surface of the damaged area on-site, without the need for 3D scanning or the process and structural parameters of the aircraft composite material component. It can quickly and accurately complete the layer-by-layer grinding work according to the preset grinding interval, without damaging adjacent composite material structural layers that do not require grinding. Simultaneously, it accurately reflects the grinding amount of the damaged area, providing key data for patch fabrication and the assessment of the remaining strength and lifespan of the aircraft composite material component.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A grinding device for aircraft composite material structures includes a grinding head, which comprises a rubber pressure plate, a clamping rubber block, a spring pressure plate, a floating head spring, a grinding head base, a grinding head housing, and a floating head. The grinding head housing contains the rubber pressure plate, the clamping rubber block, the spring pressure plate, and the grinding head base arranged sequentially from back to front. The floating head passes through the array of holes on the rubber pressure plate, the clamping rubber block, the spring pressure plate, the grinding head base, and the grinding head housing. The rubber pressure plate, which moves back and forth, squeezes or releases the clamping rubber block. The grinding head base contains a floating head spring that is engaged between the floating head shoulder and the spring pressure plate.

[0008] Furthermore, the grinding head also includes a rubber-blocking pad, flexible sandpaper, colloid, and a flocked base plate. The floating head is disposed through the array of holes in the rubber-blocking pad, the rubber-blocking pad is located where the floating head protrudes from the grinding head housing, the flocked base plate covers the end of the floating head that protrudes from the rubber-blocking pad, the floating head between the flocked base plate and the rubber-blocking pad is filled with colloid, and the front end face of the flocked base plate is provided with flexible sandpaper.

[0009] Furthermore, the grinding head also includes a dustproof rubber sleeve, a rotating pressure head, a tightening handle, a semi-circular stop block, a square stop block, a semi-circular groove and a square groove on the grinding head. The grinding head shell is a cylindrical structure that runs through the front and rear. The dustproof rubber sleeve is installed at the rear opening of the grinding head shell. The rotating pressure head is located at the rear end of the rubber pressure plate. The rotating pressure head moves back and forth inside the grinding head shell through a threaded structure. The rotating pressure head is connected to the tightening handle. The outer side of the grinding head shell is provided with a semi-circular stop block and a square stop block for directional installation. The rubber pressure plate, clamping rubber block, spring pressure plate and grinding head base are all directionally installed by matching the semi-circular groove and square groove on the grinding head to the semi-circular stop block and square stop block on the inner side of the grinding head shell.

[0010] The adhesive barrier includes a thick plastic pad, a thin plastic pad, and paper tape. The thick plastic pad is located at the rear end relative to the thin plastic pad. The floating head passes through the array of holes in the thick and thin plastic pads. Paper tape is provided between the sides of the thick and thin plastic pads.

[0011] Furthermore, it also includes a vertical base frame and a horizontal base frame. The grinding head can be detachably mounted on the vertical base frame that moves in the feed direction, and the vertical base frame is mounted on the horizontal base frame that moves in the grinding direction. The horizontal base frame has a grinding position fixing function.

[0012] Furthermore, the vertical base frame includes a lead screw slide, a smooth rod slide, and a mounting base. Both the lead screw slide and the smooth rod slide are mounted on the sliding parts of the horizontal base frame. A mounting base connects the lead screw slide and the smooth rod slide, and the grinding head is detachably mounted on the mounting base.

[0013] The lead screw slide includes a feed servo motor, a feed rolling bearing, a feed lead screw, a lead screw base, a feed ball bearing assembly, a lead screw slider, a guide spring, and a guide rod. The lead screw base is mounted on a sliding component of a horizontal base frame. The feed servo motor is mounted on the lead screw base and connected to the feed lead screw. The feed lead screw is rotatably mounted on the lead screw base via the feed rolling bearing. The feed lead screw cooperates with the feed ball bearing assembly, which is mounted on the lead screw slider. The guide rod is mounted on the lead screw base and slides with the lead screw slider. A guide spring is sleeved on the guide rod, located between the lead screw slider and the bottom of the lead screw base. The lead screw slider is connected to a mounting base.

[0014] The guide rail includes a guide rail, a guide rail base, and a guide rail slider. The guide rail base is mounted on a sliding component of a horizontal base frame. The guide rail is mounted on the guide rail base. The guide rail and the guide rail slider are in sliding engagement. A guide rail spring is sleeved on the guide rail and located between the guide rail slider and the bottom of the guide rail base. The guide rail slider is connected to the mounting base.

[0015] Both the lead screw slide and the guide screw slide include a vernier and a feed scale. Both the lead screw slider and the guide screw slider are equipped with verniers, and both the lead screw base and the guide screw base are equipped with feed scales opposite to the verniers.

[0016] The mounting base is equipped with studs and lock nuts, a countersunk plate, a semi-circular groove, and a square groove. The grinding head is detachably mounted on the countersunk plate of the mounting base via the studs and lock nuts. The mounting base achieves directional installation of the grinding head through the semi-circular groove and the square groove.

[0017] Furthermore, the lead screw slide also includes a limiting pin, a limiting screw, a cover plate, a limiting spring, a limiting square groove, a pin shoulder, a ball, an outer annular groove, and an inner annular groove. The cover plate is located on the lead screw slide. The limiting pin passes through the cover plate and the lead screw slide and engages with the feed ball device. The limiting screw is located on the cover plate and extends into the limiting square groove at the rear end of the limiting pin. A limiting spring is provided between the cover plate and the pin shoulder in the middle of the limiting pin. A ball is provided at the front end of the limiting pin, and the ball engages with the outer annular groove or the inner annular groove in the pin hole of the limiting pin.

[0018] Furthermore, the horizontal base frame includes a horizontal slide table, a universal vacuum suction cup, a grinding ball bearing device, a horizontal slider, a grinding screw, a grinding servo motor, an air pipe, a belt, a self-sealing split connector, a grinding polishing rod, a grinding rolling bearing, grinding scales, an air nozzle, an air blowing hole, and a centering mark. The horizontal slide table is equipped with a universal vacuum suction cup and a belt. The grinding servo motor is located on the horizontal slide table and connected to the grinding screw. The grinding screw is rotatably mounted on the horizontal slide table via a rolling bearing. The grinding screw cooperates with the grinding ball bearing device, which is connected to the horizontal slider. The horizontal slide table is equipped with a grinding polishing rod, which slides with the horizontal slider. The horizontal slider is connected to the fixing component of the vertical base frame.

[0019] The horizontal slide is equipped with a grinding scale, and the horizontal slider is equipped with an alignment mark corresponding to the grinding scale.

[0020] The horizontal slide is equipped with an air blowing hole, the air nozzle of which is connected to the air pipe, and the air pipe is equipped with a self-sealing separation connector.

[0021] The universal vacuum suction cup includes a suction cup anti-loosening nut, a thin nut, a ball end screw, an outer nut, a clamping sleeve, a connecting seat, a clamping handle, and a rubber suction cup. The ball end screw passes through a horizontal slide. The upper and lower ends of the ball end screw are respectively connected to the suction cup anti-loosening nut and the thin nut, which limit the movement of the horizontal slide. The ball end of the ball end screw is located in the clamping sleeve on the rubber suction cup. The outer nut is threaded onto the connecting seat of the rubber suction cup and presses against the clamping sleeve. The rubber suction cup is equipped with a clamping handle.

[0022] Furthermore, it also includes a glue injection base, which includes a glue injection base, side plates and a bottom plate. Both ends of the glue injection base can be detachably installed with grinding heads opposite to the floating heads. The left and right sides of the glue injection base are provided with side plates that can move up and down and left and right, and the bottom of the glue injection base is provided with a bottom plate that can move up and down.

[0023] Furthermore, the glue injection base also includes side plate studs, side plate washers, side plate springs, base plate mounting screws, base plate springs, wing nuts, glue injection semi-circular grooves, glue injection square grooves, oblong holes, and base plate C-shaped grooves. Oblong holes are provided on the left and right sides of the glue injection base. The side plate studs pass inward through the oblong holes and connect to the side plates. A side plate spring is provided between the glue injection base and the side plates through the side plate washers. A wing nut is provided on the side plate studs located on the outside of the glue injection base. The base plate is mounted on the glue injection base by moving up and down through the base plate mounting screws. A base plate spring is provided between the bottom of the glue injection base and the base plate. The glue injection base realizes the directional installation of the grinding head by installing the glue injection semi-circular grooves and glue injection square grooves. The end of the base plate is provided with a base plate C-shaped groove for locking the glue-blocking pad.

[0024] A grinding method for aircraft composite material structures includes the aforementioned grinding device for aircraft composite material structures, and further includes the following steps:

[0025] S01, Cleaning composite material components;

[0026] S02, select three identical grinding heads: A, B, and C;

[0027] S03, Determine the grinding direction and install the horizontal base frame on the composite material component;

[0028] S04, control the vertical base frame to feed and move, drive the grinding head A installed on the vertical base frame to feed and move, the floating head of the grinding head A contacts and fully fits the grinding area, and then the rubber pressure plate squeezes the clamping rubber block to clamp the floating head on the clamping rubber block.

[0029] S05, remove grinding head A, and obtain grinding head B in the same state as grinding head A by the same operation as in S04; set a rubber-blocking pad at the point where the floating head of grinding head A protrudes from the grinding head shell, install grinding head A and grinding head C opposite each other on the glue injection seat, set a flocked base plate between the floating heads of grinding head A and grinding head C opposite each other, and make the floating head on grinding head C contact and press the end of the floating head on grinding head A with the flocked base plate, then clamp the floating head on grinding head C, and then inject glue between the flocked base plate and the rubber-blocking pad on grinding head A. After the glue has cured, remove grinding head C and grinding head A, and attach flexible sandpaper to the grinding surface formed by the floating head, glue and flocked base plate on grinding head A.

[0030] S06, control the vertical base frame to feed and move, which drives the grinding head A mounted on the vertical base frame to feed and move. The flexible sandpaper of the grinding head A contacts and fully adheres to the grinding area. Control the horizontal base frame to grind and move, which drives the vertical base frame and the grinding head A to grind and move synchronously. The flexible sandpaper is used to grind the grinding area until the grinding is completed.

[0031] The success of grinding damaged areas of aircraft composite components has a crucial impact on whether the aircraft can continue to operate. This invention can bring the following beneficial effects:

[0032] 1) Most of the components of the grinding device of this invention are made of aluminum alloy, which greatly reduces the weight of the device and makes it possible to use a vacuum suction cup for fixing. It also allows the device to be hung upside down under the composite material components for operation. The vacuum suction cup adopts a universal structure, which makes the device suitable for various complex curved surfaces and narrow spaces, and also eliminates the limitation of needing to use a professional platform or tooling, making the application more flexible and convenient.

[0033] 2) The grinding device of this invention uses a dot-matrix floating head to measure the curved surface features of the damaged area of ​​the composite material component, and adopts a simple and effective rubber block to achieve the floating locking function, simplifying the overall structure of the device. At the same time, it innovatively combines the dot-matrix floating head with the glue injection method to perfectly replicate a curved grinding head that is the same as the curved surface of the damaged area, and provides the strength and rigidity of the grinding head. It also has a short manufacturing time and good effect, making it very suitable for grinding work in the field or in the field.

[0034] 3) Square and semi-circular grooves and blocks were designed to ensure the consistency of the curved surface direction of the grinding head.

[0035] 4) The number of floating heads can be increased or decreased according to the size of the damaged area, meeting the needs of different damage situations in reality.

[0036] 5) A mechanism for disengaging the grinding head from the feed servo motor is cleverly designed using limit pins. When the floating head is not locked, the feed servo motor can be used for feeding. When the floating head is locked, it is switched to manual feeding, which avoids the floating head hitting the tool due to misoperation.

[0037] 6) The use of a vernier provides a reliable method for positioning the grinding head and measuring the amount of grinding.

[0038] 7) The use of servo motors as the drive device for the feed and grinding directions greatly improves the motion accuracy (micrometer-level accuracy), making functions such as precise layer-by-layer grinding, oblique section grinding, and fixed-depth grinding feasible. It is also very suitable for grinding composite materials with ultra-thin, large-area curved interlayer structures, such as aircraft skin.

[0039] 8) A self-sealing split connector is adopted, which can effectively prevent the air hose from being accidentally dragged by external force, causing it to malfunction or fall off and be damaged, or even scratch the aircraft surface during the dragging process. Although the self-sealing split connector is mainly used in aircraft fuel systems, its automatic sealing and separation function under force is also very suitable for this grinding device, especially playing an indispensable role in field operations.

[0040] 9) A separate grinding head was used to measure both the regrinding and the amount of regrinding. This is because if a single grinding head were used to measure both regrinding and the amount of regrinding, the flocked base and flexible sandpaper on the grinding head would be compressible. Additionally, during the regrinding process, the resistance encountered during feeding and the clamping force of the rubber block would weaken, causing the dot-matrix floating head and the rubber block to float upwards as a whole. These compression and floating amounts are not negligible relative to the amount of regrinding. Therefore, using the same grinding head to measure the amount of regrinding would be inaccurate. Using a second grinding head ensures the accuracy of the measurement.

[0041] 10) A third grinding head was used to connect with the grinding head that needed to be injected with glue to press the flocking base sheet. The pressing of the point-to-point floating head ensured that the flocking base sheet could be completely attached to the point floating head.

[0042] 11) Although the above content, from existing problems to solutions, and then to specific implementation and working methods, is all described from the perspective of repairing defects and damage of composite material components, from the structure, working principle and usage of the device, it is also suitable for repairing small-area composite material curved surfaces. For example, the surface of a composite material component requires high precision, but after actual demolding, measurements show that there are still errors compared to the design model, requiring quantitative fine repair; another example is when assembling composite material parts for secondary bonding into components, but due to large errors in local areas, they cannot be assembled together, requiring quantitative fine repair of local areas; and so on. The repair method and device of this invention can be used in such cases, which can not only achieve micron-level repair precision, but also conform to curved surface repair, completely repairing the layers that need to be removed without damaging adjacent layers.

[0043] In summary, the grinding method and apparatus of the present invention are very suitable for grinding aircraft composite material components and have high practical application value.

[0044] The aforementioned main solution of the present invention and its various further alternative solutions can be freely combined to form multiple solutions, all of which are solutions that can be adopted and are claimed by the present invention; furthermore, the (non-conflicting alternatives) can also be freely combined with each other and with other alternatives. Those skilled in the art, after understanding the solution of the present invention, will realize from the prior art and common general knowledge that there are many combinations, all of which are technical solutions to be protected by the present invention, and will not be exhaustively listed here. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the grinding structure of the present invention.

[0046] Figure 2 This is a schematic diagram of the glue injection structure of the present invention.

[0047] Figure 3This is a structural appearance diagram of the grinding head of the present invention without adhesive.

[0048] Figure 4 This is a top view of the structure of the grinding head of the present invention.

[0049] Figure 5 yes Figure 4 A sectional view along line AA.

[0050] Figure 6 yes Figure 4 BB-direction sectional view.

[0051] Figure 7 This is an axonometric view of the vertical base frame of the present invention.

[0052] Figure 8 This is a top view of the vertical base frame of the present invention.

[0053] Figure 9 yes Figure 8 CC-direction sectional view.

[0054] Figure 10 yes Figure 8 DD section view.

[0055] Figure 11 yes Figure 8 EE-directed sectional view.

[0056] Figure 12 This is an isometric view of the horizontal base frame of the present invention.

[0057] Figure 13 This is a partial cross-sectional view of the horizontal base frame of the present invention.

[0058] Figure 14 This is an isometric view of the structure of the glue injection seat of the present invention.

[0059] Figure 15 This is a schematic diagram of the beveled cross-section of the present invention.

[0060] In the diagram: 100 - grinding head, 200 - vertical base frame, 300 - horizontal base frame, 400 - electrical controller, 500 - glue injection seat, 600 - a section of wing curved surface;

[0061] 101-Dustproof rubber sleeve, 102-Rotating pressure head, 103-Rubber pressure plate, 104-Clamping rubber block, 105-Spring pressure plate, 106-Floating head spring, 107-Grinding head base, 108-Grinding head shell, 109-Thick plastic pad, 110-Thin plastic pad, 111-Floating head, 112-Flexible sandpaper, 113-Colloid, 114-Paper tape, 115-Wool-embedded base sheet, 116-Tightening handle, 117-Semi-circular stop block, 118-Square stop block, 119-Grinding head semi-circular groove, 120-Grinding head square groove, 121-Base countersunk screw;

[0062] 201-Lead screw slide, 202-Smooth screw slide, 203-Mounting base, 204-Mounting base countersunk screw, 205-Stud and lock nut, 206-Slide countersunk screw, 207-Feed servo motor, 208-Feed rolling bearing, 209-Feed screw, 210-Lead screw base, 211-Feed ball bearing assembly, 212-Lead screw slider, 213-Limit pin, 214-Limit screw, 215-Cover plate, 216-Limit spring, 217-Smooth screw spring, 218- 219-Smooth rod base, 220-Smooth rod slider, 221-Vernier, 222-Vernier countersunk screw, 223-Cover plate countersunk screw, 224-Feed scale, 225-Slide groove, 226-Rectangular groove, 227-Counterhead, 228-Mounting seat semi-circular groove, 229-Mounting seat square groove, 230-Pull ring, 231-Limit square groove, 232-Pin shoulder, 233-Ball, 234-Outer annular groove, 235-Inner annular groove, 236-Slide table C-shaped groove;

[0063] 301-Horizontal slide table, 302-Universal vacuum suction cup, 303-Grinding ball bearing device, 304-Horizontal slider, 305-Grinding lead screw, 306-Grinding servo motor, 307-Clamp, 308-Air hose, 309-Belt, 310-Self-sealing split joint, 311-Grinding polished rod, 312-Ball countersunk screw, 313-Grinding rolling bearing, 314-Suction cup anti-loosening nut, 315-Thin nut, 316-Grinding scale, 317-Large lug, 318-Metal buckle, 319-Air nozzle, 320-Air blowing hole, 322-Ball head screw, 323-Outer nut, 324-Clamping sleeve, 325-Connecting seat, 326-Pressure handle, 327-Rubber suction cup, 328-Center mark;

[0064] 501-Injection base, 502-Side plate stud, 503-Side plate washer, 504-Side plate spring, 505-Side plate, 506-Base plate mounting screw, 507-Base plate spring, 508-Wing nut, 509-Base plate, 510-Injection mounting screw, 511-Injection semi-circular groove, 512-Injection square groove, 513-Oval hole, 514-Base plate C-groove;

[0065] 601 - Grinding surface, 602 - Composite material structural layer, 603 - Intact adjacent layer, 604 - Damaged layer, 605 - Bevel and serration, 606 - Grinding surface. Detailed Implementation

[0066] The following non-limiting examples are used to illustrate the present invention.

[0067] Example 1

[0068] like Figure 1 and Figure 2 As shown, a grinding device for aircraft composite material structures mainly consists of a grinding head 100, a vertical base frame 200, a horizontal base frame 300, an electrical controller 400, and a glue injection seat 500. The grinding head 100, vertical base frame 200, horizontal base frame 300, and electrical controller 400 are combined to form a grinding structure, completing the grinding work on damaged areas of composite material components. The grinding head 100 and glue injection seat 500 are combined to form a glue injection structure, completing the glue injection, curing, and molding of the curved surface grinding head.

[0069] like Figure 3 and Figure 5 As shown, the grinding head 100 is cylindrical in shape. When the grinding head 100 is not coated with glue, it includes a dustproof rubber sleeve 101, a rotating pressure head 102, a rubber pressure plate 103, a clamping rubber block 104, a spring pressure plate 105, a floating head spring 106, a grinding head base 107, a grinding head shell 108, and a floating head 111. After the grinding head 100 is coated with glue, it adds a glue-blocking pad (thick plastic pad 109, thin plastic pad 110, and paper tape 114), flexible sandpaper 112, glue 113, and a flocked base sheet 115.

[0070] Four perforated lugs are evenly distributed along the circumference of the upper end of the grinding head housing 108. The grinding head 100 can be fixed on the mounting base 203 of the vertical base 200 through these lugs. Four stop blocks are also evenly distributed along the circumference below the lugs, three of which are square stop blocks 118 and one is a semi-circular stop block 117. Since the orientation of the grinding head 100 is very important, these stop blocks are to ensure that the grinding head 100 can be installed on the vertical base 200 or the glue injection seat 500 in the correct orientation, so as to avoid forgetting the orientation of the curved surface to be ground when repeatedly picking up and putting down the grinding head 100, which would lead to misoperation.

[0071] The grinding head base 107 has numerous identical stepped holes in its central square area, called a square hole array. The size and spacing of the holes determine the accuracy of the grinding head 100 in conforming to the curved surface; the smaller the value, the higher the accuracy. The floating head 111 is a cylinder with a shoulder in the middle and rounded ends. One end can be inserted into the stepped hole of the grinding head base 107, and then the floating head spring 106 is placed in it. The spring pressure plate 105 is then fixed to the grinding head base 107 by four countersunk screws 121 evenly distributed around the circumference. The grinding head base 107 has bolt holes at corresponding positions, which can press the floating head spring 106 into the stepped hole of the grinding head base 107. Of course, the spring pressure plate 105 also has the same square hole array as the grinding head base 107 at the same position. In this way, the floating head 111 floats up and down a certain distance by the compression and extension of the floating head spring 106. The numerous floating heads 111 within this square area, with their rounded ends, form a lattice grinding head. When this lattice grinding head is used to fit the complex curved surface of the damaged area of ​​a composite material component, each floating head 111 in the lattice grinding head will float a different distance according to the shape of the curved surface. After the lattice grinding head is properly fitted to the curved surface, the contact points between the lattice grinding head and the curved surface form a curved point cloud. This is equivalent to scanning the curved surface using a 3D scanner and replicating it onto the overhaul grinding head 100. Figure 3 As shown in Figure 5.

[0072] Then, a clamping rubber block 104 with a hole array of the same size as the grinding head base 107 is installed on the spring pressure plate 105. The size of the holes is the same as the cylindrical diameter of the floating head 111, and the outer diameter is the same as the inner diameter of the grinding head housing 108. When the clamping rubber block 104 is compressed, the hole diameter in the hole array becomes smaller due to the limited outer diameter. This allows the floating head 111 to be tightly locked in place after the dot-matrix grinding head is properly fitted to the curved surface, preventing it from moving. A rubber pressure plate 103 is provided above the clamping rubber block 104, which also has a hole array of the same size as the grinding head base 107. The size of the holes is slightly larger than the cylindrical diameter of the floating head 111, allowing the floating head 111 to move freely within them. The rubber pressure plate 103 can evenly transmit the force from the rotating pressure head 102 to the clamping rubber block 104, ensuring uniform compression and a consistent rate of hole diameter reduction. The rotary pressure head 102 has a threaded top, which can mate with the threaded inner wall of the grinding head housing 108, allowing it to move up and down via the thread, thereby pressing the rubber pressure plate 103. The lower end of the rotary pressure head 102 is hollow, with only its outer edge contacting the rubber pressure plate 103. This design allows the floating head 111 to move up and down within it without interference. The top center of the rotary pressure head 102 has a threaded hole, which can be connected to a tightening handle 116. By tightening the handle 116, the rotary pressure head 102 is rotated, thereby compressing and releasing the clamped rubber block 104. Figure 2As shown, the top of the rotating pressure head 102 is hollowed out, allowing observation of the floating head 111 within the hole array to determine if a malfunction has occurred. The floating head 111 must maintain a certain length within the cavity of the grinding head housing 108. When not floating, one rounded end must protrude from the rubber pressure plate 103 so that the floating head 111's movement can be observed from the outside. When floating to its limit position, it must not interfere with the top of the inner cavity of the rotating pressure head 102.

[0073] like Figure 4 As shown, the rubber pressure plate 103, clamping rubber block 104, spring pressure plate 105, and floating head spring 106 all have evenly distributed grooves along their outer perimeter at the same location. Three of these are square grooves 120, and one is a semi-circular groove 119, which fit precisely into the square and semi-circular stop blocks on the inner wall of the grinding head housing 108 (the stop blocks extend from the upper threaded relief groove to the bottom of the inner cavity). This arrangement serves the same purpose as the stop blocks on the outer wall of the grinding head housing 108, ensuring that the rubber pressure plate 103, clamping rubber block 104, spring pressure plate 105, and floating head spring 106 are correctly placed inside the grinding head housing 108 without altering the already adjusted curved surface direction, thus preventing misoperation. The bottom of the grinding head base 107 has evenly distributed threaded holes along its circumference, while the grinding head housing 108 has countersunk holes at the same locations. The grinding head base 107 is fixed to the grinding head housing 108 by countersunk screws 121.

[0074] like Figure 5 As shown, after the colloid 113 cures, it bonds together with all the floating heads 111 exposed outside the grinding head housing 108, forming a whole. This greatly improves the strength and rigidity of the entire lattice grinding head, making it sufficient to withstand the resistance and vibration experienced by the entire equipment during grinding. A thin plastic pad 110 is provided above the colloid 113 and is bonded to the colloid by adhesive. A thick plastic pad 109 is bonded to the thin plastic pad 110 by adhesive. Both plastic pads have the same array of holes as the grinding head base 107 in the middle, mainly to prevent the colloid from entering the grinding head housing 108 and to act as a stop (detailed in the method of colloid injection). Paper tape 114 is provided at the contact boundary between the two plastic pads to prevent the colloid from overflowing from the contact boundary between the two plastic blocks. The dot-matrix grinding head and the colloid form a curved surface identical to the damaged area of ​​the composite component. A flexible flocked substrate 115 is adhered to this curved surface. The flocked substrate 115 and flexible sandpaper 112 are bonded together using Velcro, and both are very thin, tightly adhering to the curved surface formed by the dot-matrix grinding head and the colloid, maintaining the same curvature. The Velcro connection allows for easy replacement of the flexible sandpaper 112, meeting the needs of sandpaper consumption. Figure 6 As shown, the grinding head 100 is also provided with a dustproof rubber sleeve 101 on the top, which is directly fitted on the top by the elasticity of the rubber, making it easy to install and remove. Its function is to prevent dust from entering the interior of the grinding head during grinding.

[0075] like Figure 7 As shown, the vertical base 200 includes a lead screw slide 201, a smooth rod slide 202, and a mounting base 203. Both the lead screw slide 201 and the smooth rod slide 202 are fixed to the horizontal slider 304 in the horizontal base 300 by four countersunk screws 206. The horizontal slider 304 has corresponding threaded blind holes. The mounting base 203 is U-shaped, with four threaded through holes on each of its two wings. It is connected to the lead screw slider 212 in the lead screw slide 201 and the smooth rod slider 220 in the smooth rod slide 202 by eight countersunk screws 204, allowing it to move up and down with the lead screw slide 201 and the smooth rod slide 202. The inner concave surface of the mounting base 203 has a countersunk platform 227, the shape of which is the same as the shape of the four lugs on the top of the grinding head 100, thus restricting the rotation of the grinding head 100 around its axis. The countersunk surface is also evenly provided with four grooves along its circumference, three of which are square grooves 229 for mounting seats and one is a semi-circular groove 228 for a semi-mounting seat. This ensures that the curved surface at the bottom of the grinding head 100 faces the same direction each time it is installed. The countersunk surface is provided with four studs and anti-loosening nuts 205, which can securely install the grinding head 100 on the mounting seat 203.

[0076] like Figure 7 , Figure 8 , Figure 9 and Figure 10 As shown, the lead screw slide 201 includes a feed servo motor 207, a feed rolling bearing 208, a feed lead screw 209, a lead screw base 210, a feed ball bearing device 211, a lead screw slider 212, a limit pin 213, a limit screw 214, a cover plate 215, a limit spring 216, a guide spring 217, a slide guide rod 218, a vernier 221, and a vernier countersunk screw 222.

[0077] The feed servo motor 207 is located on the top left side of the lead screw base 210 and connected to the feed lead screw 209. Both ends of the feed lead screw 209 are placed on feed rolling bearings 208, which are interference-fitted to the top and bottom of the lead screw base 210. The feed lead screw 209 has a cuboid feed ball device 211, which is installed in the rectangular groove 226 of the lead screw slider 212. A limiting blind hole is provided on one side of the middle of the feed ball device 211. A limiting pin 213 passes through this blind hole to lock the feed ball device 211 and the lead screw slider 212 together. Thus, the feed servo motor 207 drives the feed ball device 211 via the feed lead screw 209, simultaneously causing the lead screw slider 212 to slide up and down. The feed servo motor 207, feed screw 209 and feed ball device 211 are used together to provide wire-level feed accuracy. This is because the skin of most aircraft wings and fuselages is very thin, some may only be about 2mm thick, while each layer of composite material is only a few tenths of a millimeter thick. Only by using such feed accuracy can the precision of grinding layer by layer be guaranteed, and the next layer will not be damaged when grinding the previous layer of composite material.

[0078] A slide rail 218 is mounted on the right side of the lead screw base 210. The slide rail 218 and the feed lead screw 209 are on the same plane. The slide rail 218 passes through the through hole on the upper right side of the lead screw base 210, all the way to the threaded hole at the bottom of the lead screw base 210, and passes through the stepped hole on the right side of the lead screw slider 212. A rail spring 217 is installed in the stepped hole. The rail spring 217 can ensure that the lead screw slider 212 slides more smoothly and silkily when sliding up and down, and will not move.

[0079] The limiting pin 213 can lock the feed ball device 211 and the lead screw slider 212 together, and can also be pulled out. Specifically, the limiting pin 213 is installed in the stepped hole in the middle of the left side of the lead screw slider 212. A limiting spring 216 is installed in the stepped hole. The limiting spring 216 is pressed into the stepped hole by the cover plate 215 through four cover plate countersunk screws 223, which also installs the limiting pin in the stepped hole of the lead screw slider 212. The end of the limiting pin 213 is provided with a ball 233. Under normal conditions, the ball is pushed out and firmly embedded in the inner annular groove 235 in the stepped hole of the lead screw slider. Since the limiting pin 213 has a pin shoulder 232 in the middle, as long as the limiting pin 213 is installed in place, the limiting pin will accurately insert into the limiting hole of the feed ball device 211, and the ball will be embedded in the inner annular groove. Only when the pull ring 230 is pulled outward will the ball be released and the limiting pin 213 be pulled out. When the limiting pin 213 is pulled out, because the end of the limiting pin 213 has a limiting square groove 231, and the limiting screw 214 is threaded onto the cover plate 215, the end of the limiting screw is inserted into the limiting square groove of the limiting pin. When the limiting pin 213 is pulled out a certain distance, it will be restricted by the limiting screw 214. At this time, the ball is also located in the outer annular groove 234. First, hold the end of the limiting pin 213, then release the pull ring, and finally release the end of the limiting pin 213. In this way, the limiting pin 213 is locked in the position of the outer annular groove. At this time, the feed ball device 211 is disengaged from the lead screw slider 212, and the grinding head 100 can slide freely manually with the lead screw slider 212 and the polishing rod slider 220.

[0080] like Figure 7 and Figure 9 As shown, the vernier 221 is mounted on the back of the lead screw slider 212 via a vernier countersunk screw 222. The connection point between the vernier 221 and the back of the lead screw slider 212 is located within a groove 225 on the side of the lead screw base 210. The vernier 221 slides within the groove as the lead screw slider 212 moves, and the groove also serves as a limiting mechanism. The side of the lead screw base 210 is engraved with feed graduations 224, similar to those on a vernier caliper, that mate with the vernier 221. The accuracy of these graduations is also at the micrometer level, matching the feed accuracy of the servo motor.

[0081] like Figure 7 , Figure 8 , Figure 9 and Figure 11As shown, the guide slide 202 includes a guide spring 217, a guide rod 218, a guide rod base 219, a guide rod slider 220, a vernier 221, and a vernier countersunk screw 222. Similar to the lead screw slide 201, the two guide rods 218 pass through the guide holes on both sides of the guide rod base 219 until they are fixed in the threaded hole at the bottom. The axes of the two guide rods 218 are in the same plane and pass through the guide rod slider 220. The guide rod slider 220 also has a stepped hole, which houses the guide spring 217 to ensure smooth and non-moving operation of the grinding head 100. The sides of the guide slide 202 also have the same vernier, groove, and scale as the lead screw slide 201.

[0082] like Figure 7 As shown, a lead screw, three guide rods, and a guide rod spring make the grinding head run more smoothly and stably. Figure 11 As shown, both the lead screw base 210 and the guide rod base 219 are provided with a slide C-shaped groove 236, which is used to facilitate the installation of eight mounting seat countersunk screws 204.

[0083] like Figure 12 and Figure 13 As shown, the horizontal base frame 300 includes a horizontal slide table 301, a universal vacuum suction cup 302, a grinding ball bearing device 303, a horizontal slider 304, a grinding lead screw 305, a grinding servo motor 306, a clamp 307, an air pipe 308, a belt 309, a self-sealing split joint 310, a grinding polishing rod 311, a ball countersunk screw 312, and a grinding rolling bearing 313. The universal vacuum suction cup 302 includes a suction cup anti-loosening nut 314, a thin nut 315, a ball head screw 322, an outer nut 323, a clamping sleeve 324, a connecting seat 325, a clamping handle 326, and a rubber suction cup 327.

[0084] The horizontal slide 301 serves as the support platform for the equipment. Four large lugs 317 are evenly distributed around its perimeter. Each lug has a boss with a clear hole inside. The ball-end screw 322 of the universal vacuum suction cup 302 passes through this hole, is positioned below by a common thin nut 315, and is secured above by a suction cup anti-loosening nut 314. The universal vacuum suction cup 302 can slide up and down within the boss as needed. Slightly loosening the outer nut 323, rotating the suction cup to the desired angle, and then tightening the outer nut compresses the clamping sleeve 324, firmly fixing the ball-end screw in one direction. The outer nut 323 is threadedly connected to the connecting seat 325, allowing for omnidirectional rotation of the vacuum suction cup. This enables the entire equipment to be fixed to the complex curved surface of the composite material component using the four vacuum suction cups. This nut and screw fixing method allows for direct replacement of custom-made suction cups when encountering composite material component surfaces with excessive curvature variations or limited space, without requiring structural modifications, providing significant structural flexibility. The vacuum suction cup has a thick rubber suction cup 327 at the bottom. By pressing down on the handle 326, the entire universal vacuum suction cup 302 can be firmly attached to the curved surface, making it very suitable for use on structures with smooth outer surfaces, such as wings and fuselages.

[0085] A grinding servo motor 306 is mounted on the side flange of the horizontal slide table 301. The grinding servo motor 306 is connected to a grinding lead screw 305. The grinding lead screw 305 passes through a grinding rolling bearing 313 (obscured in the figure) mounted on the side flange of the horizontal slide table 301 and the left-side aperture of the horizontal slider 304, extending to a grinding rolling bearing 313 on the other side flange of the horizontal slide table 301. The grinding rolling bearing 313 is fitted into the aperture of the horizontal slide table 301 via an interference fit. On the other side of the horizontal slide table 301, a grinding guide rod 311 passes through the horizontal slide table 301 and the horizontal slider 304, extending to a threaded hole on the side flange of the horizontal slide table 301, thus fixing it to the horizontal slide table 301. A grinding ball bearing device 303 is mounted in the middle section of the grinding lead screw 305. The grinding ball bearing device 303 is fixed to the horizontal slider 304 by ball countersunk screws 312. The horizontal slider 304 has corresponding threaded blind holes. The grinding screw 305 and the grinding guide rod 311 are parallel and their axes are in the same plane, so that the servo motor can stably drive the horizontal slider 304 to reciprocate along the axis of the grinding screw 305. The horizontal base 300 also has a displacement accuracy at the micrometer level, and can complete reciprocating motion within a very small range.

[0086] The horizontal slide 301 has grinding graduations 316 on its left and right large lugs, and the horizontal slider also has centering marks 328 on both sides of its middle section. This design allows for easy identification of the grinding head 100's position and facilitates its re-alignment. Both the horizontal slide 301 and the horizontal slider 304 are hollowed out in the middle, allowing the grinding head to move freely without interference. Figure 1 and Figure 12 As shown, the large lugs have oblong holes on both sides and are equipped with belts 309. These belts allow the equipment to be secured to the composite material component. The belts have a high roughness, ensuring good contact with the surface of the composite material component. This has two advantages: first, it further secures the equipment, ensuring it adheres firmly to the curved surface of the composite material component; second, it prevents the equipment from accidentally detaching due to a person or object snagging the air pipe, or from scratching the surface of the composite material component if it falls, thus protecting the equipment from damage if it falls. The length of the belt can be selected according to the cross-sectional size of the composite material component and is locked with metal buckles 318. Oblong holes are located on both sides of the four large lugs, allowing for selection of the securing location based on the specific site conditions.

[0087] like Figure 12 and Figure 13 As shown, the horizontal slide table 301 has air holes at both ends. Below each air hole is an angled air blower 320, with the outlet facing the grinding head 100. An air pipe 308 is connected to the air nozzle 319 above the air hole via a clamp 307. The air pipe 308 is connected to a self-sealing split connector 310 (male end) via the clamp 307. The self-sealing split connector 310 is connected to an air pipe from the air compressor via the clamp 307. This allows the grinding debris generated during grinding to be blown away, facilitating better grinding and observation of the grinding process. The self-sealing split connector 310 plays a crucial role here. If someone accidentally snags the air pipe and is about to pull the entire device, the pulling force will cause the male and female ends of the self-sealing split connector 310 to separate (for detailed working principle, see patent ZL202210321563.5), thus closing the air path. In this way, the air pipe and female connector at the air compressor end are pulled away, but the air pipe and male connector at the equipment end remain stationary, thus keeping the entire equipment fixed in its original position. This situation is very likely to occur during field refurbishment operations, so the self-sealing split connector 310 provides excellent protection.

[0088] like Figure 2 and Figure 14As shown, the glue injection base 500 includes a glue injection base 501, side plate studs 502, side plate washers 503, side plate springs 504, side plates 505, base plate mounting screws 506, base plate springs 507, wing nuts 508, and a base plate 509. The glue injection base 501 forms the basic frame of the entire glue injection base 500. It has large holes on its front and rear end faces and four grooves evenly distributed along its circumference: three are square grooves 512, and one is a semi-circular groove 511. The function of these grooves is the same as that of the grooves on the grinding head 100, ensuring that the grinding surface at the bottom is aligned each time the grinding head is inserted into the glue injection base 500. It also has four threaded through holes, primarily for connecting the grinding head 100. The glue injection base 501 has four large windows on both sides for observing the entire glue injection process. The sides have parallel, waist-shaped holes 513 of a certain length in the middle. Four side plate studs 502 are installed in the slots, arranged in a rectangular pattern, with their tails connected to the threaded holes of the side plates 505. A side plate spring 504 is installed on the side plate studs 502 between the side plates 505 and the inner wall of the injection base 501. A side plate washer 503 is provided at the end of the side plate spring 504 (on the inner wall side of the injection base 501) to expand the area and support the side plate spring 504. A wing nut 508 is connected to the outer part of the side plate stud 502 on the injection base 501. By tightening and loosening the wing nut 508, the length of the side plate stud 502 extending into the injection base 501 and its position on the waist-shaped holes can be adjusted. This allows the side plates 505 to move up and down and in and out, providing a certain clamping force on the object being pressed. The base plate 509 is located below the side plate 505, and its four corners are fixed to the four threaded holes of the glue injection base 501 by base plate mounting screws 506. A base plate spring 507 is provided between the base plate 509 and the bottom of the glue injection base 501, so that the base plate 509 can move up and down and exert a certain clamping force on the object being pressed.

[0089] The reason for designing the base plate 509 to move vertically and the two side plates 505 (symmetrically designed) to move vertically and horizontally, and inwards and outwards, is that the number of floating heads 111 in the grinding head 100 can be increased or decreased according to the damaged area of ​​the composite material component. Therefore, the size of the rectangular area of ​​the dot matrix grinding head composed of floating heads 111 is different. Thus, the base plate 509 and side plates 505 must be designed to be movable to press the floating heads 111 of the grinding head 100 tightly before adhesive injection can be performed. The base plate 509 has C-shaped grooves 514 at the front and rear. The function of these grooves is that after the grinding head 100 is installed, the thick plastic pad 109 and the thin plastic pad 110 are installed. At this time, because they are not fully cured, these two plastic pads are not fixed. When the base plate is in place, the C-shaped grooves precisely lock these two plastic pads in place, fixing them in place. Figure 2 and Figure 14As shown, the length of the glue injection base is designed so that when the two grinding heads 100 are installed into the glue injection base, the floating head 111 will be compressed, and then the flocking base 115 is pressed close to the curved point cloud of the damaged area of ​​the composite material component that has been replicated, so as to facilitate the subsequent glue injection operation.

[0090] like Figure 1 As shown, the electrical controller 400 mainly controls the servo motor, and it can adjust the displacement magnitude, displacement direction and speed of the feed direction and grinding direction.

[0091] Example 2

[0092] A grinding method for aircraft composite material structures includes the grinding device for aircraft composite material structures described in Example 1, and further includes the following steps.

[0093] Clean composite material components (such as wings or fuselage, etc.). Figure 1 (Taking a 600° curved section of an airfoil as a reference example) Impurities and stains on the surface of the damaged area. If there are protruding fragments of damaged material in the damaged area, the protruding parts can be repaired with a knife (this situation is relatively rare; more often, the outer surface does not show any damage, but the interior has delamination, fragmentation, etc.). Then, a square grinding area is delineated. The size of the grinding area should not be smaller than the damaged area, and at the same time, it should match the size of the dot matrix grinding head composed of floating heads (because floating heads can be added or removed, and the size of the square area they form increases or decreases according to the spacing between the floating heads).

[0094] Install three grinding heads, A, B, and C (all three are identical at this stage). Tightening handles and dust covers are not required. (Place the floating head and its spring into the grinding head base. Secure the spring plate with countersunk screws. Then, insert the clamping rubber blocks and rubber plates sequentially into the dot-matrix floating head, paying attention to the orientation of the square and semi-circular slots, and place them into the grinding head housing.) Determine the number of floating heads based on the determined grinding interval dimensions, and ideally, they should be installed symmetrically along the length and width. At this stage, the clamping rubber blocks do not need to be tightened; the floating heads can float freely up and down. Then, install grinding head A into the mounting bracket of the vertical base frame.

[0095] Determine the grinding direction and fix the base frame. For example... Figure 1 As shown, the curvature variations of aircraft composite components, such as wings or fuselages, can be roughly divided into two categories: First, most surfaces exhibit significant curvature variations in the width direction (or radial direction of the fuselage section) *v*, while the variation in the wingspan direction (or length direction of the fuselage) *u* is minimal. Second, a small portion of surfaces show large curvature variations in all directions, such as the sections where various wings intersect with the fuselage. However, regardless of the type of surface, due to the grinding surface 601 (e.g., ... Figure 1The grinding surface here is just an example, not a real one, used only to illustrate the effect of grinding surfaces in different curvature directions. Grinding back and forth in the grinding direction within a very small range (equivalent to rubbing in place) can achieve high grinding accuracy. Of course, if the grinding direction is consistent with the wingspan direction (or fuselage length direction), then layer-by-layer grinding without damaging the layers can be achieved (because the curvature change of the grinding surface in the u-direction can be considered zero, and the composite material in the reciprocating motion area of ​​the grinding surface can be considered uniformly laid along the u-direction, with no change in thickness), resulting in the highest grinding accuracy. This is the most common case, as surfaces with the first type of curvature change are predominant. If the second case is encountered, the grinding direction should be chosen in the direction of least curvature change. This can improve the grinding range (it's difficult to achieve a grinding range that is too small) and grinding accuracy; this situation is rare. After determining the grinding direction, adjust the height and angle of the universal vacuum suction cups to ensure that the grinding direction of the grinding device is basically consistent with the selected direction, and that the suction cups can adhere well to the surface of the composite material component. Then, adjust the position so that the dot-matrix floating head of grinding head A completely covers the designated grinding area (at this time, the centering mark of the horizontal slider should be at the zero mark; if not, please reset it to the zero mark first). After confirming coverage, press down the clamping handle to firmly fix the suction cups to the surface of the composite material component. Then, make fine adjustments by loosening the suction cup anti-loosening nuts and outer nuts, and adjusting the height of the four universal vacuum suction cups and the direction of the rubber suction cups to ensure that the grinding direction of the grinding device is completely consistent with the selected direction. If the position of grinding head A and the grinding direction deviate during the process, repeatedly adjust the position of the universal vacuum suction cups until the requirements are met. Finally, tighten the suction cup anti-loosening nuts, thin nuts, and outer nuts. Next, select a suitable belt to further secure the grinding device to the composite material component, fixing it firmly in place. Connect the electrical controller, then the air hose and self-sealing split connector, and finally the air compressor. Confirm that the limit pin is in the inner annular groove.

[0096] Set a very slow feed speed, start the feed servo motor, and visually observe the contact between the grinding head A and the grinding area. If they are in complete contact, turn off the feed servo motor. Then, observe whether the floating head moves up and down normally by rotating the pressure head. If it is normal, tighten the rotating pressure head with the tightening handle to press the clamping rubber block, thereby locking the floating head completely in position. If it is not normal, reinstall the floating head. At this time, read the vernier reading and record it as E1.

[0097] Then, remove grinding head A and install grinding head B. Perform the same operation as with grinding head A, tightening the clamping rubber blocks to lock all floating heads in position. Then, remove grinding head B. At this point, the floating heads in grinding heads A and B move up and down in basically the same way, and the curved point cloud of the damaged area is replicated onto the dot matrix floating head.

[0098] Place and secure the grinding head A on its side. Apply a suitable amount of adhesive to the perforated area on the surface of the thick plastic pad that contacts the thin plastic pad. Then, insert the pad into the dot-matrix floating head. The floating head will then be coated with adhesive. Next, insert the thin plastic pad into the dot-matrix floating head. Since the holes in the thin plastic pad are smaller, the adhesive on the floating head can be squeezed into the holes of the thick plastic pad. Then, seal the joint between the two plastic pads with masking tape to prevent adhesive overflow during injection. Let it stand for a few minutes to allow the adhesive to slightly harden and stop flowing. This operation ensures that the adhesive will not enter the grinding head base through the perforation during injection. Then, tighten the wing nut, open the side plates on both sides of the injection base, apply release wax to the two side plates and the base plate, and attach 1-2 layers of composite material cloth (the release wax makes it easier to demold after the adhesive has cured, and the composite material cloth acts as a sealant). Press down the base plate, install the grinding head A, and tighten the screws. After the grinding head A is installed, the base plate will automatically rise and the C-groove will wrap around and hold the two plastic pads in place, providing stability and a seal. Then, cut the flocked base piece to the size of the grinding area, leaving a length H on both sides of the glue-injection base as shown. Figure 5 As shown, to wrap around both sides, place the flocked base into the glue injection base, close to the dot matrix floating head of the grinding head A, and then install the grinding head C into the other side of the glue injection base. Since the grinding head A has locked the floating head, while the grinding head C has not, the floating head will be compressed when the grinding head C is installed into the glue injection base, thereby pressing the flocked base. Adjust the length reserved on both sides of the flocked base so that it fits exactly against the side of the floating head. Then tighten the handle to press the clamping rubber block and lock the floating head of the grinding head C. Then loosen the wing nut to flatten the flocked base on the side of the floating head.

[0099] At this point, the two side plates and the base plate form a sealed groove with an open top, tightly encasing the dot matrix floating head A. Next, prepare the glue and slowly pour it into the groove. Since the diameter of the floating head is smaller than the distance between the two floating heads, there is a gap between the floating heads, allowing the glue to penetrate to the bottom. You can appropriately prick the bottom of the glue base during the process to fill the entire groove with glue. When the glue rises to the upper edge of the flocked base, you can stop pouring glue. At this point, the glue just covers the entire dot matrix floating head of the grinding head A. Let it stand for about an hour to cure.

[0100] After the glue has cured, tighten the wing nuts, slowly open both side panels, remove the grinding head C, gently press down on the base plate, remove the grinding head A, take it out, and then grind along the grinding surface 606 (e.g. Figure 5 After trimming burrs and other defects caused by adhesive injection at the edges, flexible sandpaper, pre-cut to the dimensions of the grinding area, is applied to the grinding surface formed by the flocked substrate, adhesive, and floating head (if any portion extends beyond the grinding surface, it needs to be trimmed). At this point, the curved surface of the damaged area of ​​the composite material component has been successfully replicated.

[0101] Turn on the feed servo motor, raise the mounting base to a certain height, and then turn it off. Next, install the grinding head A. Then pull out the limit pin to disengage the grinding head A from the servo motor. Slowly press down on the grinding head A so that the flexible sandpaper on the grinding head A fully adheres to the curved surface of the damaged area of ​​the composite material. Record the vernier reading as F1. Then reset the grinding head and the limit pin. Next, start the servo motor to lower the grinding head A until the vernier reaches the F1 reading. Stop the feed servo motor. At this point, the flexible sandpaper on the grinding head A is fully adhered to the curved surface of the damaged area of ​​the composite material. The grinding process then begins.

[0102] The feed speed of the servo motor and the reciprocating motion range of the servo motor are set according to requirements: for the first curvature case, the reciprocating motion range can be set larger; for the second curvature case, the reciprocating motion range can be set smaller. Furthermore, different reciprocating ranges can be set for different feed depths, thus creating a region with a beveled cross-section. The smaller the difference in the reciprocating motion range between different depths, the more depth divisions are possible, the smaller the bevel and serration 605, the smoother the bevel, and the easier it is to repair. Figure 15 As shown. Different depths require different reciprocating motion ranges, and realignment is necessary before each grinding. Through the coordination of the feed servo motor and the grinding servo motor, various grinding results can be achieved, such as grinding a specific number of layers (the operator needs to visually determine whether all damaged layers have been ground, as it's unknown which layers are damaged; therefore, the feed speed and amount for each grinding session must be calculated and observed during the process), grinding a specific depth, directly grinding through, grinding beveled sections, or grinding straight sections, etc., to meet different grinding needs. During the grinding process, the flexible sandpaper on grinding head A also needs to be replaced promptly. The flexible sandpaper is attached using Velcro, which is very convenient. Before grinding, the air compressor needs to be turned on to blow away grinding debris, and an anti-wear rubber sleeve should be placed on grinding head A. After grinding, the air compressor should be turned off.

[0103] After grinding is complete, control the grinding head A to rise to a certain height, then disassemble grinding head A and install grinding head B. Pull out the limit pin, positioning it in the outer annular groove. At this point, grinding head B is disengaged from the feed servo motor. Manually press down grinding head B, allowing the floating head on grinding head B to slowly conform to the ground surface. Once fully conformed, read the vernier reading E2 to obtain the grinding thickness E = E2 - E1. The cross-sectional shape or thickness of the ground surface is an important parameter for fabricating repair patches and re-estimating the remaining strength and lifespan of composite material components. Finally, reset grinding head B and the limit pin.

[0104] Open the belt and universal vacuum suction cup, disassemble the grinding device, and clean the grinding area. Then, place grinding head A into the solvent to dissolve the colloid for future use.

[0105] The foregoing basic examples and their further alternative examples of the present invention can be freely combined to form multiple embodiments, all of which are embodiments that can be adopted and are claimed by the present invention. In the present invention, each alternative example can be arbitrarily combined with any other basic example and alternative example.

[0106] 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, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A grinding device for aircraft composite material structures, comprising a grinding head (100), characterized in that: The grinding head (100) includes a rubber pressure plate (103), a clamping rubber block (104), a spring pressure plate (105), a floating head spring (106), a grinding head base (107), a grinding head shell (108), and a floating head (111). The grinding head shell (108) is provided with the rubber pressure plate (103), the clamping rubber block (104), the spring pressure plate (105), and the grinding head base (107) in sequence from back to front. The floating head (111) is provided in the array of holes on the rubber pressure plate (103), the clamping rubber block (104), the spring pressure plate (105), the grinding head base (107), and the grinding head shell (108). The rubber pressure plate (103) moves back and forth to squeeze or release the clamping rubber block (104). The grinding head base (107) is provided with a floating head spring (106) that is locked between the floating head shoulder and the spring pressure plate (105) in the array of holes. The grinding head (100) further includes a rubber-blocking pad, flexible sandpaper (112), colloid (113), and a flocked base plate (115). The floating head (111) is disposed through the array of holes in the rubber-blocking pad. The rubber-blocking pad is located where the floating head (111) passes through the grinding head housing (108). The flocked base plate (115) covers the end of the floating head (111) that passes through the rubber-blocking pad. The floating head (111) between the flocked base plate (115) and the rubber-blocking pad is filled with colloid (113). The front end face of the flocked base plate (115) is provided with flexible sandpaper (112).

2. The grinding device for aircraft composite material structures according to claim 1, characterized in that: The grinding head (100) further includes a dustproof rubber sleeve (101), a rotating pressure head (102), a tightening handle (116), a semi-circular stop block (117), a square stop block (118), a semi-circular groove (119) and a square groove (120) of the grinding head. The grinding head housing (108) is a cylindrical structure that runs through the front and back. The dustproof rubber sleeve (101) covers the rear opening of the grinding head housing (108). The rotating pressure head (102) is located at the rear end of the rubber pressure plate (103). The rotating pressure head (102) is located outside the grinding head and moves back and forth through a threaded structure. Inside the housing (108), the rotating pressure head (102) is connected to the tightening handle (116). The outer side of the grinding head housing (108) is provided with a semi-circular stop block (117) and a square stop block (118) for directional installation. The rubber pressure plate (103), the clamping rubber block (104), the spring pressure plate (105) and the grinding head base (107) are all directionally installed by matching the semi-circular groove (119) and the square groove (120) of the grinding head on them with the semi-circular stop block (117) and the square stop block (118) on the inner side of the grinding head housing (108). The adhesive barrier includes a thick plastic pad (109), a thin plastic pad (110), and paper tape (114). The thick plastic pad (109) is located at the rear end relative to the thin plastic pad (110). The floating head (111) is disposed through the holes in the thick plastic pad (109) and the thin plastic pad (110). The paper tape (114) is provided between the sides of the thick plastic pad (109) and the thin plastic pad (110).

3. The grinding device for aircraft composite material structures according to claim 1, characterized in that: It also includes a vertical base frame (200) and a horizontal base frame (300). The grinding head (100) is detachably mounted on the vertical base frame (200) that moves in the feed direction. The vertical base frame (200) is mounted on the horizontal base frame (300) that moves in the grinding direction. The horizontal base frame (300) has a grinding position fixing function.

4. The grinding device for aircraft composite material structures according to claim 3, characterized in that: The vertical base frame (200) includes a lead screw slide (201), a smooth rod slide (202), and a mounting base (203). The lead screw slide (201) and the smooth rod slide (202) are both mounted on the sliding parts of the horizontal base frame (300). The mounting base (203) connects the lead screw slide (201) and the smooth rod slide (202). The grinding head (100) is detachably mounted on the mounting base (203). The lead screw slide (201) includes a feed servo motor (207), a feed rolling bearing (208), a feed lead screw (209), a lead screw base (210), a feed ball bearing assembly (211), a lead screw slider (212), a guide spring (217), and a slide guide rod (218). The lead screw base (210) is mounted on a sliding member of a horizontal base frame (300). The feed servo motor (207) is mounted on the lead screw base (210) and connected to the feed lead screw (209). The feed lead screw (209) is connected to the feed ball bearing (209) via the feed rolling bearing (208). 8) Rotary mounting on the lead screw base (210), the feed lead screw (209) cooperates with the feed ball device (211), the feed ball device (211) is mounted on the lead screw slider (212), the slide table guide rod (218) is mounted on the lead screw base (210), the slide table guide rod (218) and the lead screw slider (212) are slidably engaged, the slide table guide rod (218) is fitted with a guide rod spring (217) located between the bottom of the lead screw slider (212) and the lead screw base (210), and the lead screw slider (212) is connected to the mounting base (203); The smooth rod slide (202) includes a smooth rod (218), a smooth rod base (219), and a smooth rod slider (220). The smooth rod base (219) is mounted on the sliding member of the horizontal base frame (300). The smooth rod (218) is mounted on the smooth rod base (219). The smooth rod (218) and the smooth rod slider (220) are slidably engaged. A smooth rod spring (217) is sleeved on the smooth rod (218) and located between the bottom of the smooth rod slider (220) and the smooth rod base (219). The smooth rod slider (220) is connected to the mounting base (203). Both the lead screw slide (201) and the guide screw slide (202) include a vernier (221) and a feed scale (224). The lead screw slider (212) and the guide screw slider (220) are provided with vernier (221), and the lead screw base (210) and the guide screw base (219) are provided with a feed scale (224) opposite to the vernier (221). The mounting base (203) is provided with studs and anti-loosening nuts (205), a countersunk plate (227), a semi-circular groove (228) and a square groove (229). The grinding head (100) is detachably mounted on the countersunk plate (227) of the mounting base (203) through the studs and anti-loosening nuts (205). The mounting base (203) realizes the directional installation of the grinding head (100) through the semi-circular groove (228) and the square groove (229).

5. The grinding device for aircraft composite material structures according to claim 4, characterized in that: The aforementioned lead screw slide (201) also includes a limiting pin (213), a limiting screw (214), a cover plate (215), a limiting spring (216), a limiting square groove (231), a pin shoulder (232), a ball bearing (233), an outer annular groove (234), and an inner annular groove (235). The cover plate (215) is provided on the lead screw slide (212). The limiting pin (213) passes through the cover plate (215) and the lead screw slide (212) and then connects with the feed ball bearing device (214). 1) The limiting screw (214) is located on the cover plate (215) and extends into the limiting square groove (231) at the rear end of the limiting pin (213). A limiting spring (216) is provided between the cover plate (215) and the pin shoulder (232) in the middle of the limiting pin (213). A ball (233) is provided at the front end of the limiting pin (213). The ball (233) is engaged with the outer annular groove (234) or the inner annular groove (235) in the pin hole of the limiting pin (213).

6. The grinding device for aircraft composite material structures according to claim 3, characterized in that: The horizontal base frame (300) includes a horizontal slide (301), a universal vacuum chuck (302), a grinding ball bearing device (303), a horizontal slider (304), a grinding lead screw (305), a grinding servo motor (306), an air pipe (308), a belt (309), a self-sealing split joint (310), a grinding polishing rod (311), a grinding rolling bearing (313), a grinding scale (316), an air nozzle (319), an air blowing hole (320), and a centering mark (328). The horizontal slide (301) is equipped with a universal vacuum chuck (302) and a belt (303). 09), The grinding servo motor (306) is mounted on the horizontal slide (301) and connected to the grinding screw (305). The grinding screw (305) is rotatably mounted on the horizontal slide (301) via the rolling bearing (313). The grinding screw (305) cooperates with the grinding ball device (303). The grinding ball device (303) is connected to the horizontal slider (304). The horizontal slide (301) is provided with a grinding rod (311). The grinding rod (311) is slidably engaged with the horizontal slider (304). The horizontal slider (304) is connected to the fixing part of the vertical base frame (200). The horizontal slide (301) is provided with a grinding scale (316), and the horizontal slider (304) is provided with a centering mark (328) opposite to the grinding scale (316). The horizontal slide (301) is provided with an air blowing hole (320), the air nozzle (319) of the air blowing hole (320) is connected to the air pipe (308), and the air pipe (308) is provided with a self-sealing separation connector (310). The universal vacuum suction cup (302) includes a suction cup anti-loosening nut (314), a thin nut (315), a ball head screw (322), an outer nut (323), a clamping sleeve (324), a connecting seat (325), a pressing handle (326), and a rubber suction cup (327). The ball head screw (322) is mounted on the horizontal slide (301). The upper and lower ends of the ball head screw (322) are respectively connected to the suction cup anti-loosening nut (314) and the thin nut (315) to limit the horizontal slide (301). The ball head of the ball head screw (322) is located inside the clamping sleeve (324) on the rubber suction cup (327). The outer nut (323) is threaded onto the connecting seat (325) of the rubber suction cup (327) and presses the clamping sleeve (324). The rubber suction cup (327) is provided with a pressing handle (326).

7. The grinding device for aircraft composite material structures according to claim 3, characterized in that: It also includes a glue injection base (500), which includes a glue injection base (501), side plates (505) and a bottom plate (509). Both ends of the glue injection base (501) are detachably equipped with grinding heads (100) opposite to floating heads (111). The left and right sides of the glue injection base (501) are provided with side plates (505) that can move up and down and left and right. The bottom of the glue injection base (501) is provided with a bottom plate (509) that can move up and down.

8. The grinding device for aircraft composite material structures according to claim 7, characterized in that: The glue injection base (500) further includes a side plate stud (502), a side plate washer (503), a side plate spring (504), a base plate mounting screw (506), a base plate spring (507), a wing nut (508), a glue injection semi-circular groove (511), a glue injection square groove (512), an oblong hole (513), and a base plate C-shaped groove (514). The glue injection base (501) has oblong holes (513) on both the left and right sides. The side plate stud (502) passes inward through the oblong hole (513) and connects to the side plate (505). The glue injection base (501) is connected to the side plate (505) via the side plate washer (503). 5) A side plate spring (504) is provided between them. A wing nut (508) located outside the glue injection base (501) is provided on the side plate stud (502). The base plate (509) is moved up and down on the glue injection base (501) by the base plate mounting screw (506). A base plate spring (507) is provided between the bottom of the glue injection base (501) and the base plate (509). The glue injection base (501) realizes the orientation installation of the grinding head (100) by installing the glue injection semi-circular groove (511) and the glue injection square groove (512). The end of the base plate (509) is provided with a base plate C-shaped groove (514) for locking the glue blocking pad.

9. A grinding method for aircraft composite material structures, characterized in that, The grinding apparatus for aircraft composite material structures according to any one of claims 7-8 further includes the following steps: S01, Cleaning composite material components; S02, select three identical grinding heads (100) A, B and C. S03, determine the grinding direction, and install the horizontal base frame (300) on the composite material component; S04, control the vertical base frame (200) to feed and move, drive the grinding head A installed on the vertical base frame (200) to feed and move, the floating head (111) of the grinding head A contacts and fully fits the grinding area, and then the rubber pressure plate (103) squeezes the clamping rubber block (104) to clamp the floating head (111) on the clamping rubber block (104); S05, remove grinding head A, and obtain grinding head B in the same state as grinding head A by the same operation in S04; set a rubber-blocking pad at the point where the floating head (111) of grinding head A protrudes from the grinding head housing (108), and install grinding head A and grinding head C opposite each other on the glue injection seat (500), and set a flocking base sheet (115) between the floating heads (111) of grinding head A and grinding head C opposite each other, so that the floating head (111) on grinding head C realizes the flocking base sheet. (115) Contact the end of the floating head (111) on the grinding head A, then clamp the floating head (111) on the grinding head C, and then inject the adhesive (113) between the flocked base plate (115) and the rubber pad on the grinding head A. After the adhesive has cured, remove the grinding head C and the grinding head A, and attach the flexible sandpaper (112) to the grinding surface formed by the floating head (111), the adhesive (113) and the flocked base plate (115) on the grinding head A. S06, control the vertical base frame (200) to feed and move, drive the grinding head A installed on the vertical base frame (200) to feed and move, the flexible sandpaper (112) of the grinding head A contacts and fully adheres to the grinding area, control the horizontal base frame (300) to grind and move, drive the vertical base frame (200) and the grinding head A to grind and move synchronously, use the flexible sandpaper (112) to grind the grinding area until the grinding is completed.

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