Robot end device and method for cementing and pre-curing composite stringer

Abstract

The invention discloses a robot terminal device and method for glue joint and precuring of a composite material stringer. The robot terminal device comprises a bearing seat, a power unit, a flexible clamping unit, a flexible pressing and fixing unit, a heating temperature control unit and a flange assembly. During operation, the robot carries the device to move to a stringer storage area, the power unit drives the flexible clamping unit to get close to flexibly clamp a stringer vertical plate, and the heating temperature control unit synchronously adjusts the angle and the telescopic length, so that a heating surface is parallel to a flange; the robot drives the device and the clamped stringer to move to a glue joint coordinate according to a preset path, and the downward pressing device and the flexible pressing and fixing unit are matched with the height difference of the flanges to ensure that the stringer is attached to the skin in a gapless mode; after the pressing and fixing force reaches a preset value, a heating temperature control unit starts infrared heating and heats and cures a glue joint area according to set parameters, and a temperature sensor controls the temperature in real time; and curing of a single area is completed, the robot slightly lifts the device, the pressing and fixing wheel is separated from the stringer, each unit is reset, and the next round of curing operation is carried out.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of long string pre-curing tooling, more specifically, relates to a robot end device and method for composite long string bonding pre-curing. BACKGROUND

[0002] The current connection of composite long string and wall panel skin in the field of aviation is mainly in the form of bonding. Compared with traditional mechanical connection (such as rivet connection), it can avoid stress concentration problem and significantly reduce the number of parts and assembly process, and greatly improve the work efficiency. In order to ensure the bonding performance of the composite long string, the common bonding process is usually adopted, that is, the long string is bonded with the semi-cured skin after being bonded together, so as to ensure that the long string bonding surface can be combined with the resin of the semi-cured skin, and the shrinkage stress in the co-curing process is avoided.

[0003] However, the existing common bonding method has many technical defects, which is difficult to meet the batch production and high-quality production requirements of aviation composite wall panels. The specific problems are as follows: (1) low positioning efficiency, poor precision and high cost: the positioning link of the existing common bonding relies on manual disassembly and assembly of customized tooling, and different types and specifications of long strings need to be designed and manufactured separately. The tooling has poor universality, which not only leads to low positioning efficiency and poor positioning precision, but also greatly increases the cost of tooling design, processing and maintenance; (2) uneven distribution of pressing force: the pressing process relies on manual adjustment of force, and the bonding degree of the long string and the skin is judged by the experience of the operator, lacking precise force control means, which easily causes uneven distribution of pressing force, and then directly affects the mechanical properties of the wall panel; (3) workpiece is prone to processing defects: during positioning and pre-tightening, manual operation and contact with rigid tooling can easily damage the skin, even cause skin cracking and other problems, which seriously restricts the production quality and large-scale production capacity of aviation composite wall panels.

[0004] Therefore, at present, a long string bonding pre-curing device is needed, which can significantly improve the positioning precision and efficiency, and improve the workpiece processing quality and optimize the bonding interface quality, which is suitable for batch production and high-quality production of aviation composite wall panels. SUMMARY

[0005] In view of the problems of low positioning precision, uneven distribution of pressing force and easy defects of the existing long string skin common bonding method, the present application provides a robot end device and method for composite long string bonding pre-curing to solve such problems.

[0006] To achieve the above object, the application provides a robot end device for composite stringer bonding pre-solidification, which comprises a bearing seat rigidly connected with a robot end; power units symmetrically arranged at two ends of the bearing seat, each group of power units comprising two groups of fixing frames driven by output power to move towards or away from each other along the horizontal longitudinal direction; the fixing frame comprising an outer connecting rod and an inner connecting rod; a flexible clamping unit arranged at the lower end of the outer connecting rod, comprising a first flexible component and a clamping wheel; the first flexible component absorbs rigid collision kinetic energy to enable the two groups of clamping wheels to flexibly clamp the side edges of the stringer vertical plate; a flexible pressing unit arranged at the lower end of the inner connecting rod, comprising a second flexible component and a pressing wheel; the second flexible component absorbs rigid collision kinetic energy generated by the pressing wheel pressing downward to enable the pressing wheel to flexibly press the stringer flange; a heating temperature control unit arranged along the horizontal transverse direction, the two ends of which are respectively horizontally hinged to the flexible pressing unit, comprising an outer heating module and an extension rod; the robot carrying device moves to the stringer storage area, the power unit drives the flexible clamping unit to clamp the stringer vertical plate, the heating temperature control unit synchronously adjusts the angle and the extension length to make the heating surface parallel to the flange; the robot carrying the device and the clamped stringer move to the bonding coordinate according to the preset path, the device is pressed downward, the flexible pressing unit adapts to the height difference of the flange to ensure that the stringer and the skin are gaplessly attached; after the pressing force reaches the preset value, the heating temperature control unit starts infrared heating, the bonding area is heated and solidified according to the set parameters, the temperature sensor controls the temperature in real time, and the solidification work of the bonding area is completed.

[0007] Further, the first flexible component comprises a first flexible support frame, a first guide rod, a first sliding plate and a first spring; wherein the first flexible support frame is fixedly arranged at the lower end of the outer connecting rod; a plurality of groups of first guide rods are arranged in parallel, the other ends of the plurality of groups of first guide rods are fixedly connected with the first sliding plate through the first flexible support frame; the first sliding plate is adapted to the inner cavity of the first flexible support frame, and slides linearly in the inner cavity of the first flexible support frame along the horizontal longitudinal direction; the first spring is sleeved on the first guide rod, one end of which is connected with the first sliding plate and the other end is connected with the inner wall surface of the first flexible support frame; the clamping wheel is arranged along the horizontal longitudinal direction, the wheel frame of which is fixedly connected with one end of the plurality of groups of first guide rods.

[0008] Further, the flexible pressing unit comprises a second flexible component, a pressing wheel and a connecting frame; the second flexible component comprises a second flexible support frame, a second guide rod, a second sliding plate and a second spring; wherein the second flexible support frame is fixedly arranged at the lower end of the inner connecting rod, and sliding grooves are symmetrically arranged on both sides of the frame body; a plurality of second guide rods are arranged in parallel along the vertical direction, and the top and bottom parts are fixedly connected with the top and bottom parts of the inner cavity of the second flexible support frame; the second sliding plate is sleeved on the plurality of second guide rods, and is linearly lifted along the second guide rod, and the two ends pass through the sliding grooves and are connected with the connecting frame and the heating temperature control unit; the second spring is sleeved on the second guide rod, one end of which is connected with the second sliding plate, and the other end is connected with the inner wall surface of the second flexible support frame; the connecting frame is a right-angled triangular frame, the vertical right-angled side is fixedly connected with one end of the second sliding plate, and the horizontal right-angled side is fixedly connected with the wheel frame of the pressing wheel.

[0009] Further, the infrared heating module is arranged in two groups along the horizontal transverse direction, and the two ends are connected with the other end of the second sliding plate through the hinge seat; one end of the telescopic rod is fixedly arranged in the heating module, and the other end is fixedly connected with the rocker arm of the hinge seat; when the rocker arm rotates in the horizontal direction, the telescopic rod is driven to extend or retract, so as to perform angle self-adaptive adjustment, so that the heating surface is always parallel to the flange; the temperature sensor is arranged at the bottom of the bearing seat to detect the temperature of the area to be glued.

[0010] Further, the bearing seat is an H-shaped structure, comprising a bearing plate, mounting plates symmetrically arranged at both ends of the bearing plate along the horizontal longitudinal direction, and connecting plates fixedly connected with the center of the end of the bearing plate and the center of the inner side of the mounting plate at the longitudinal two ends respectively; the connecting plates are respectively provided with displacement grooves at the longitudinal two ends to allow the fixed frame of the power unit to pass through.

[0011] Further, the power unit further comprises a driving component, a transmission component and a linear displacement component.

[0012] Further, the transmission component comprises a first bevel gear and a second bevel gear; the first bevel gear is fixedly arranged on the motor shaft of the motor; the second bevel gear is arranged in two groups along the vertical direction, and the two groups of second bevel gears are symmetrically arranged on both sides of the first bevel gear and are in meshing connection with the first bevel gear; the linear displacement component is used to drive the two groups of fixed frames to synchronously linearly displace, and is arranged in two groups and symmetrically arranged at both ends of the motor mounting frame, comprising a guide rail, a sliding block, a screw nut, a lead screw and a bearing seat; the guide rail is fixedly arranged on the bearing plate along the horizontal longitudinal direction; the sliding block is slidingly arranged on the guide rail, and the side edge is fixedly provided with a screw nut; the lead screw lever body is in threaded connection with the screw nut, one end is connected with the second bevel gear through a shaft coupling, and the second bevel gear is rotated to drive the lead screw to rotate; the bearing seat is vertically fixedly arranged at the end of the mounting plate, and is in rotational connection with the other end of the lead screw.

[0013] Furthermore, the fixing frame is a portal frame spanning the mounting plate, including an outer connecting rod and an inner connecting rod, the inner sides of which are respectively fixedly connected to both sides of the slider.

[0014] According to another aspect of the present invention, a method for pre-curing adhesive bonding of composite stringers is also provided, comprising the following steps:

[0015] S1: The robot moves the device to the stringer storage area. The power unit drives the flexible clamping unit to approach and flexibly clamp the stringer vertical plate. The heating temperature control unit adjusts the angle and extension length simultaneously to make the heating surface parallel to the flange.

[0016] S2: The robot moves along the preset path with the device and the clamped stringer to the bonding coordinates, and the pressing device and flexible clamping unit adapt to the flange height difference to ensure that the stringer and the skin are bonded without gaps.

[0017] S3: After the compressive force reaches the preset value, the heating temperature control unit starts infrared heating and heats and cures the adhesive area according to the set parameters. The temperature sensor controls the temperature in real time.

[0018] S4: Once a single area has been solidified, the robot slightly lifts the device, the pressure rollers separate from the stringer, and each unit is reset.

[0019] S5: The robot with the device moves along the stringer to the next bonding area, and repeats steps S2-S4 until all areas are pre-cured.

[0020] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

[0021] 1. The robot end effector of the present invention eliminates the need for manual assembly and disassembly of tooling. The robot drives the device along a preset path, and a power unit drives a flexible clamping unit to flexibly clamp the stringer vertical plate. The positioning process is fully automated, with positioning efficiency three times higher than manual methods. The flexible clamping unit of this device adaptively adjusts the clamping force via a first spring, making it compatible with stringers of different cross-sectional sizes. This eliminates the need for separate tooling designs for each specification, significantly reducing tooling design, processing, and maintenance costs, and increasing versatility by over 80%. Relying on the robot's operational precision, combined with the rigid connection between the bearing seat and the flange assembly, the stringer is ensured to move precisely to the preset bonding coordinates after clamping, with positioning deviation controlled within ±0.1mm, far superior to manual positioning accuracy. This achieves efficient, accurate, and universal automated positioning.

[0022] 2. The robot end effector of the present invention achieves adaptive pressure adjustment, avoiding uneven local pressure in the bonding area. The flexible compression unit converts the robot's downward pressure into elastic potential energy through a second spring. For the convex area on the bottom surface of the stringer flange, the spring compresses to absorb excess pressure; for the concave area, the spring extends to supplement the pressure, ensuring uniform distribution of compression force at all points of the flange. During the compression process, the pressure sensor at the robot end provides real-time feedback of the reaction force. When the pressure reaches the preset value required for bonding, the downward pressure automatically stops, avoiding insufficient or excessive pressure caused by manual judgment based on experience, ensuring no gap between the stringer and the skin bonding surface. Furthermore, the flexible compression unit works in conjunction with the heating and temperature control unit to perform heating operations. The compression state continues until the heating and curing are completed, maintaining stable pressure throughout the process, avoiding gaps or delamination in the bonding due to pressure relaxation during the curing process, and improving the bonding interface fusion by more than 20%.

[0023] 3. The robot end effector of this invention uses flexible contact instead of rigid collision. The flexible clamping unit contacts the stringer vertical plate through clamping wheels, and the flexible clamping unit contacts the flange through clamping wheels. With the buffering effect of springs, the hard contact between traditional rigid tooling and the workpiece is completely avoided, greatly reducing the risk of skin scratches and cracks. The heating and temperature control unit uses infrared directional heating, combined with a temperature sensor to form a closed-loop temperature control, avoiding local overheating that could lead to carbonization or performance degradation of the composite resin. At the same time, the heating range only covers the bonding area, reducing the thermal impact on non-working areas. The entire operation process does not require manual intervention, avoiding bumps and damage to the workpiece during manual handling and adjustment, and eliminating human operation errors, thereby improving the workpiece qualification rate.

[0024] 4. The robot end effector of the present invention improves the continuity and stability of operation and reduces the cost of large-scale production; the device can complete pre-curing area by area along the surface of the stringer without waiting for overall curing, thus shortening the adhesive bonding production cycle; the bearing seat, power unit, flexible unit and other components are all modular structures, and damaged parts can be replaced individually without the need for overall scrapping, which greatly reduces maintenance costs; through standardized flange components, it can be connected to mainstream industrial robots and can be quickly integrated into existing aerospace composite panel production lines without large-scale modification of the production line, thus adapting to the needs of batch and streamlined production. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a robot end effector for pre-curing adhesive bonding of composite stringers according to an embodiment of the present invention;

[0026] Figure 2 This is a bottom view of the robot end effector in an embodiment of the present invention;

[0027] Figure 3 This is a left view of the robot end effector in an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of the structure of the functional units connected to both ends of the support in an embodiment of the present invention;

[0029] Figure 5 This is a schematic diagram of the structure of the support base in an embodiment of the present invention;

[0030] Figure 6 This is a schematic diagram of the flexible clamping unit in an embodiment of the present invention;

[0031] Figure 7 This is a schematic diagram of the flexible compression unit and the heating temperature control unit in an embodiment of the present invention;

[0032] Figure 8 This is a schematic diagram of the flexible compression unit in an embodiment of the present invention;

[0033] Figure 9 This is a schematic diagram of the structure of the second flexible support frame in an embodiment of the present invention;

[0034] Figure 10 This is a schematic diagram of the structure of the second flexible support frame in an embodiment of the present invention;

[0035] Figure 11 This is a schematic diagram of the operation of flexibly clamping a long truss vertical plate with a uniform cross-section in an embodiment of the present invention;

[0036] Figure 12 This is a schematic diagram of the operation of flexibly clamping the variable cross-section long truss vertical plate in an embodiment of the present invention;

[0037] Figure 13 This is a flowchart illustrating the operation of the robot end effector in an embodiment of the present invention.

[0038] Figure 14 This is a schematic diagram of the operation of the pre-cured T-shaped stringer of the robot end effector in an embodiment of the present invention.

[0039] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically:

[0040] 1-Bearing base, including: 11-Bearing plate, 12-Mounting plate, 13-Connecting plate, 14-Leaning groove;

[0041] 2-Power unit, including: 21-Drive assembly, 211-Motor, 212-Motor mounting frame, 22-Transmission assembly, 221-First bevel gear, 222-Second bevel gear, 23-Linear displacement assembly, 231-Guide rail, 232-Slider, 233-Lead screw nut, 234-Lead screw, 235-Bearing seat, 24-Fixed frame, 241-Outer connecting rod, 242-Inner connecting rod;

[0042] 3- Flexible clamping unit, including: 31- First flexible support frame, 32- Clamping wheel, 33- First guide rod, 34- First sliding plate, 35- First spring, 36- Reinforcing connecting block;

[0043] 4-Flexible clamping unit, including: 41-clamping wheel, 42-connecting frame, 43-second flexible support frame, 44-sliding groove;

[0044] 5-Heating temperature control unit, including: 51-Infrared heating module, 52-Telescopic rod, 53-Hinge seat.

[0045] 6-Flange assembly, including: 61-Flange, 62-Flange fixing plate, 63-Support column. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0047] like Figures 1-10As shown, this invention provides a robot end effector for pre-curing composite stringer bonding, comprising a support base 1, a power unit 2, a flexible clamping unit 3, a flexible compression unit 4, a heating and temperature control unit 5, and a flange assembly 6. The support base 1 is rigidly connected to the robot end effector via the flange assembly 6 at the top. The power unit 2 comprises two sets, symmetrically arranged at both ends of the support base 1, including a drive assembly 21, a transmission assembly 22, a linear displacement assembly 23, and a fixing frame 24. The drive assembly 21 outputs power to the transmission assembly 22, and the linear displacement assembly 23... With the assistance of component 23, the two sets of fixed frames 24 are simultaneously driven to move closer or further apart along the horizontal longitudinal direction; the flexible clamping unit 3 is set on the fixed frame 24, and the two sets of fixed frames 24 move closer to each other to flexibly clamp the stringer vertical plate; the flexible pressing unit 4 is set on the fixed frame 24, and includes a pressing wheel 41, which is pressed down by the robot end-effector to press and press, and 41 flexibly presses and presses the stringer flange; the heating temperature control unit 5 is set horizontally, and its two ends are respectively horizontally hinged to the flexible pressing unit 4, including an external heating module 51 and a telescopic rod 52. When the device of the present invention is in operation, the robot end-capture device moves to the storage area, and the power units 2 at both ends of the bearing seat 1 drive the flexible clamping units 3 to move closer together to flexibly clamp the two sides of the stringer vertical plate. The heating and temperature control unit 5 adjusts the hinge angle and extension length according to the change of the vertical plate cross section to keep the heating surface parallel to the flange. The robot drive device clamps the T-shaped stringer and moves it to the preset coordinate position along the preset path. It presses down to make the T-shaped stringer fully fit the skin surface. When pressing down, the flexible pressing unit 4 converts the pressure into elastic potential energy according to the height difference of the flange bottom surface to avoid uneven pressure caused by the height difference of the flange bottom surface, ensures that there is no gap between the T-shaped stringer and the skin adhesive surface and avoids excessive local pressure that may cause deformation of the skin or stringer. After the positioning and pressing operation is completed, the heating and temperature control unit heats the adhesive area according to the set parameters. After curing, the robot drives the end-capture device to move slowly along the stringer surface. After reaching the next area, the heating and curing is restarted again. The process is repeated until all areas to be glued are pre-cured. The robot end effector of the present invention avoids rigid contact between the tooling and the stringer and skin through the flexible clamping unit 3 and the flexible pressing unit 4; the fully automated operation reduces human intervention and effectively reduces the risk of skin damage and stringer displacement; the single-point pre-curing design reduces adhesive gap defects and significantly improves the workpiece processing quality.

[0048] like Figures 1-4As shown, in this embodiment of the invention, the support seat 1 is used to install and fix other functional units, and to transmit the driving force of the robot end to the flexible clamping unit 4 so that there is no gap between the stringer and the skin adhesive surface. At the same time, the reaction force of the stringer and the skin is stably fed back to the pressure sensor provided at the robot end, so as to avoid local stress concentration that could cause component damage or operational deviation. The support seat 1 has an H-shaped structure, including a support plate 11, mounting plates 12 arranged symmetrically at both ends of the support plate 11 along the horizontal longitudinal direction, and connecting plates 13 fixedly connected to the center of the end of the support plate 11 and the center of the inner side of the mounting plate 12 at both ends of the longitudinal direction, respectively. The connecting plates 13 are provided with clearance grooves 14 at both ends of the longitudinal direction to allow the fixing frame 24 of the power unit 2 to pass through.

[0049] The top of the support base 1 is fixedly connected to the robot end effector via a flange assembly 6 to ensure stable transmission of force and motion. The flange assembly 6 includes a flange 61, a flange fixing plate 62, and support columns 63. The flange 61 is fixedly mounted on the top of the flange fixing plate 62 and is fixedly connected to the robot end effector via bolts. There are four sets of support columns 63 along the vertical direction, with their tops fixedly connected to the four bottom corners of the flange fixing plate 62 and their bottoms fixed to the top of the support base 1. The support columns 63 are used to increase the height of the flange 61 and prevent the robot's movement path from interfering with other functional units.

[0050] like Figure 6 As shown, in this embodiment of the invention, the power unit 2 provides a stable driving force for the stringer clamping, driving the flexible clamping unit 3 to complete the clamping action of the stringer vertical plate; the power unit 2 includes a driving component 21, a transmission component 22, a linear displacement component 23 and a fixing frame 24.

[0051] The drive assembly 21 includes a motor 211 and a motor mounting frame 212. The mounting frame 212 is fixedly disposed at the center of the mounting plate 12, and the motor 211 is fixedly disposed at the top of the motor mounting frame 212. Its motor shaft passes through the top of the motor mounting frame 212 and is connected to the transmission assembly 22.

[0052] The transmission assembly 22 converts the vertical power of the motor 211 into horizontal power, and includes a first bevel gear 221 and a second bevel gear 222. The first bevel gear 221 is fixedly mounted on the motor shaft of the motor 211. The second bevel gear 222 is provided in two sets along the vertical direction, and the two sets of second bevel gears 222 are symmetrically arranged on both sides of the first bevel gear 221, and both mesh with the first bevel gear 221.

[0053] The linear displacement assembly 23 is used to drive the two sets of fixed frames 24 to move synchronously in a linear direction. It has two sets, which are symmetrically arranged at both ends of the motor mounting frame 212. It includes a guide rail 231, a slider 232, a lead screw nut 233, a lead screw 234, and a bearing seat 235. The guide rail 231 is fixedly mounted on the bearing plate 11 in a horizontal longitudinal direction. The slider 232 is slidably mounted on the guide rail 231, and the lead screw nut 233 is fixedly mounted on its side. The lead screw 234 is threadedly connected to the lead screw nut 233. One end is connected to the second bevel gear 222 through a coupling. The rotation of the second bevel gear 222 drives the lead screw 234 to rotate. The bearing seat 235 is vertically fixed at the end of the mounting plate 12 and is rotatably connected to the other end of the lead screw 234.

[0054] The fixing frame 24 is used to install and fix the flexible clamping unit 3 and the flexible pressure unit 4. It has two sets, which are symmetrically arranged on both sides of the drive assembly 21. The fixing frame 24 is a portal frame that spans the mounting plate 12. It includes an outer connecting rod 241 and an inner connecting rod 242, the inner sides of which are fixedly connected to both sides of the slider 232.

[0055] When the power unit 2 of the present invention is in operation, the motor 211 starts and outputs vertical power, which is transmitted to the first bevel gear 221 of the transmission assembly 22 via the motor shaft. The first bevel gear 221 drives the second bevel gear 222 meshing on both sides to rotate, converting the vertical power into horizontal power. The second bevel gear 222 drives the connected lead screw 234 to rotate. The lead screw 234 is threadedly engaged with the lead screw nut 233. Under the limit of the guide rail 231 on the slider 232, the slider 232 is driven to move horizontally along the guide rail 231. The slider 232 drives the connected fixing frame 24, so that the two sets of fixing frames 24 move closer or further apart in the horizontal longitudinal direction, providing the power for the flexible clamping unit 3 to clamp or release the long stringer vertical plate.

[0056] like Figure 7As shown in the embodiment of the present invention, the flexible clamping unit 3 is used to flexibly clamp the stringer vertical plate, solving the problems of workpiece damage and uneven force distribution caused by traditional rigid clamping. It can also adapt to stringers with different cross-sections, providing crucial support for high-quality pre-curing operations. The flexible clamping unit 3 includes a first flexible component and clamping wheels 32. The first flexible component absorbs the kinetic energy of rigid collisions, allowing the clamping wheels 32 to flexibly clamp the side of the stringer vertical plate. It includes a first flexible support frame 31, a first guide rod 33, a first sliding plate 34, and a first spring 35. The first flexible support frame 31 is fixedly mounted on the outer... The lower end of the connecting rod 241; multiple sets of the first guide rods 33 are arranged in parallel, and the other end of the multiple sets of first guide rods 33 passes through the first flexible support frame 31 and is fixedly connected to the first sliding plate 34; the first sliding plate 34 is adapted to the inner cavity of the first flexible support frame 31, and slides linearly in the inner cavity of the first flexible support frame 31 along the horizontal longitudinal direction; the first spring 35 is sleeved on the first guide rod 33, one end of which is connected to the first sliding plate 34, and the other end is connected to the inner wall of the first flexible support frame 31; the clamping wheel 32 is arranged along the horizontal longitudinal direction, and its wheel frame is fixedly connected to one end of the multiple sets of first guide rods 33.

[0057] Furthermore, to enhance the connection strength between the first flexible support frame 31 and the outer connecting rod 241, the flexible clamping unit 3 also includes a strong connecting block 36. The strong connecting block 36 is a right-angled triangular block, with one right-angled side fixedly connected to the outer connecting rod 241 and the other right-angled side fixedly connected to the first flexible support frame 31, thereby effectively enhancing the connection strength between the first flexible support frame 31 and the outer connecting rod 241.

[0058] In this embodiment of the invention, when the flexible clamping unit 3 performs flexible clamping operations, the power unit 2 drives the two sets of fixing frames 24 to move closer together, causing the clamping wheels 32 of the two sets of flexible clamping units 3 to move towards both sides of the vertical plate of the stringer until the clamping wheels 32 contact the sides of the vertical plate; as the fixing frames 24 continue to move closer, the clamping wheels 32 are subjected to the reaction force of the vertical plate, and push the first guide rod 33 towards the inner cavity of the first flexible support frame 31 through the wheel frame; the first guide rod 33 drives the first sliding plate 34 to move synchronously, compressing the first spring 35, and springing... The spring is compressed and generates a reverse elastic force, which is transmitted to the clamping wheel 32 through the first sliding plate, guide rod, and wheel frame, so that the clamping wheel 32 fits tightly against the surface of the vertical plate with appropriate force. When the spring compression reaches the preset value (corresponding to the preset clamping force), the power unit 2 stops driving. At this time, the clamping force of the clamping wheel 32 on the vertical plate is stable within the set range, realizing flexible clamping. Furthermore, when there are slight dimensional deviations or uneven surfaces in the cross-section of the vertical plate, the spring can adaptively adjust the clamping force through extension and retraction to avoid excessive local pressure that could damage the vertical plate.

[0059] like Figures 8-10As shown in the embodiment of the invention, the flexible clamping unit 4 achieves flexible clamping of the stringer flange, solving the problems of uneven pressure distribution and skin / stringer damage caused by traditional rigid clamping. It also adapts to the height difference of the flange bottom surface, ensuring no gap between the stringer and the skin adhesive surface, providing a key guarantee for high-quality adhesive pre-curing. The flexible clamping unit 4 includes a second flexible component, a clamping wheel 41, and a connecting frame 42. The second flexible component includes a second flexible support frame 43, a second guide rod, a second sliding plate, and a second spring. The second flexible support frame 43 is fixedly mounted on the lower end of the inner connecting rod 242, and its frame has symmetrical sliding openings on both sides. The groove 44; multiple second guide rods are arranged parallel to each other in the vertical direction, and their top and bottom are respectively fixedly connected to the top and bottom of the inner cavity of the second flexible support frame 43; the second sliding plate is sleeved on multiple second guide rods, so that it can move up and down in a straight line along the second guide rods, and its two ends pass through the sliding groove 44 and are respectively connected to the connecting frame 42 and the heating temperature control unit 5; the second spring is sleeved on the second guide rod, one end of which is connected to the second sliding plate, and the other end is connected to the inner wall of the second flexible support frame 43; the connecting frame 42 is a right-angled triangle, its vertical right-angled side is fixedly connected to one end of the second sliding plate, and its horizontal right-angled side is fixedly connected to the wheel frame of the pressure wheel 41.

[0060] In this embodiment of the invention, when the flexible pressing unit 4 performs the pressing operation, the device posture is adjusted so that the pressing wheel 41 is aligned with the surface to be pressed on the stringer flange, ensuring that the pressing wheel covers the critical bonding area of ​​the flange. The robot end effector initiates the pressing program, and the downward pressure is transmitted through the bearing seat 1 → inner connecting rod 242 → second flexible support frame 43, pushing the second sliding plate to slide downward along the second guide rod. The second sliding plate drives the pressing wheel 41 to approach the stringer flange through the connecting frame 42 until the pressing wheel 41 contacts the flange surface for height difference adaptive adjustment. For protruding areas, the pressing wheel receives a larger reaction force, pushing the connecting frame 42 and the second sliding plate to compress the second spring upward. The spring compression generates a reverse elastic force, converting excess pressure into elastic potential energy, avoiding excessive local pressure in protruding areas that could cause flange or skin deformation. For recessed areas, the reaction force is smaller, and the second sliding plate is compressed by the robot's downward pressure and the spring force. Under the combined action, the robot slides downward along the second guide rod, causing the pressure roller to fit tightly against the flange surface of the recessed area, avoiding gaps in the adhesive surface due to insufficient pressure in the recessed area. When the pressure sensor at the end of the robot detects that the reaction force reaches the preset value (corresponding to the optimal pressure required for adhesive bonding), the robot stops pressing down. At this time, the second spring maintains a stable elastic force, the pressure of the pressure roller on the flange is evenly distributed, and the stringer and skin adhesive surfaces are completely bonded without gaps. After the heating temperature control unit 5 starts heating, the flexible pressure unit 4 continues to maintain the pressure state throughout the curing process. After the curing of a single area is completed, the robot end stops outputting pressure and slightly lifts the device, separating the pressure roller 41 from the stringer flange. The second spring loses the external squeezing force and gradually returns to its natural extension state, pulling the second sliding plate upward along the second guide rod back to the initial position. The connecting frame 42 and the pressure roller 41 reset synchronously, preparing for the next area pressure operation.

[0061] like Figure 8 As shown, the heating temperature control unit 5, through angle adaptive adjustment, ensures that the heating surface is always parallel to the flange and moves in conjunction with the flexible pressing unit 4 to maintain the heating surface at the optimal heating distance, thereby precisely heating the area to be bonded. The heating temperature control unit 5 includes an infrared heating module 51, a telescopic rod 52, a hinge seat 53, and a temperature sensor. The infrared heating module 51 heats the area to be bonded by connecting to a power source. It has two sets arranged horizontally, with each end connected to the other end of the second sliding plate via the hinge seat 53. One end of the telescopic rod 52 is fixedly installed inside the heating module 51, and the other end is fixedly connected to the rocker arm of the hinge seat 53. When the rocker arm rotates horizontally, it drives the telescopic rod 52 to extend and retract, thereby adaptively adjusting the angle to ensure that the heating surface is always parallel to the flange. The temperature sensor is located at the bottom of the support seat 1 to detect the temperature of the area to be bonded.

[0062] In this embodiment of the invention, when the heating and temperature control unit 5 is operating, after the robot carrying the end effector completes the clamping of the stringer, the rocker arm of the hinge seat 53 rotates horizontally according to the cross-sectional shape of the stringer vertical plate. As the rocker arm rotates, it simultaneously drives the telescopic rod 52 to extend and retract, adjusting the distance and angle between the two sets of infrared heating modules 51 to ensure that the heating surface of the heating module remains parallel to the surface of the stringer flange, avoiding uneven local heating. The robot end effector applies downward pressure for flexible clamping, and the second sliding plate simultaneously pulls the hinge seat 53 up and down, keeping the distance between the infrared heating module 51 and the flange surface within the optimal heating range. If there is a slight height difference in the stringer flange, when the second sliding plate of the flexible clamping unit 4 slightly rises and falls, the hinge seat 53 and the telescopic rod 52 simultaneously fine-tune the heating. The module position ensures that the heating distance and angle are always adapted, eliminating localized temperature dead zones. When the pressure of the flexible pressing unit 4 reaches the preset value, the infrared heating module 51 is powered on and heats up, directionally heating the area to be bonded. The temperature sensor collects the temperature of the bonding area in real time and feeds the data back to the control system. If the temperature is lower than the preset curing temperature, the system automatically increases the module power; if the temperature is higher than the set value, the power is reduced or heating is paused, forming a closed-loop temperature control. After a single bonding area is cured, the robot's end effector slightly lifts the device, the second sliding plate of the flexible pressing unit 4 resets, and the hinge seat 53 and the infrared heating module 51 return to their initial positions. The telescopic rod 52 retracts, the hinge seat rocker arm resets, and the robot moves the device to the next bonding area.

[0063] The robot end effector of this invention eliminates the need for manual assembly and disassembly of tooling. Driven by a robot, the device moves along a preset path, and a power unit drives a flexible clamping unit to flexibly hold the stringer vertical plate. The positioning process is fully automated, improving positioning efficiency by three times compared to manual methods. The flexible clamping unit adaptively adjusts the clamping force via a first spring, making it compatible with stringers of different cross-sectional sizes. This eliminates the need for custom tooling design for each specification, significantly reducing tooling design, processing, and maintenance costs, and increasing versatility by over 80%. Leveraging the robot's operational precision and the rigid connection between the support and flange assembly, the stringer is ensured to move precisely to the preset bonding coordinates after clamping, with positioning deviation controlled within ±0.1mm, far superior to manual positioning accuracy. This achieves efficient, accurate, and universal automated positioning.

[0064] The robot end effector of this invention achieves adaptive pressure adjustment, avoiding uneven local pressure in the bonding area. The flexible compression unit converts the robot's downward pressure into elastic potential energy through a second spring. For the convex areas on the bottom surface of the stringer flange, the spring compresses to absorb excess pressure; for the concave areas, the spring extends to supplement the pressure, ensuring uniform distribution of compression force at all points on the flange. During the compression process, the pressure sensor at the robot end provides real-time feedback of the reaction force. When the pressure reaches the preset value required for bonding, the compression automatically stops, avoiding insufficient or excessive pressure caused by manual judgment based on experience, ensuring no gaps between the stringer and the skin bonding surface. Furthermore, the flexible compression unit works in conjunction with the heating and temperature control unit to perform heating operations. The compression state continues until the heating and curing are complete, maintaining stable pressure throughout the process, preventing gaps or delamination due to pressure relaxation during curing, and improving the bonding interface fusion by more than 20%.

[0065] The robot end effector of this invention uses flexible contact instead of rigid collision. The flexible clamping unit contacts the stringer vertical plate through clamping wheels, and the flexible clamping unit contacts the flange through clamping wheels. With the buffering effect of springs, the hard contact between traditional rigid tooling and the workpiece is completely avoided, greatly reducing the risk of skin scratches and cracks. The heating and temperature control unit uses infrared directional heating, combined with a temperature sensor to form a closed-loop temperature control, avoiding local overheating that could lead to carbonization or performance degradation of the composite resin. At the same time, the heating range only covers the bonding area, reducing the thermal impact on non-working areas. The entire operation process requires no manual intervention, avoiding bumps and damage to the workpiece during manual handling and adjustment, and eliminating human operation errors, thereby improving the workpiece qualification rate.

[0066] The robot end effector of this invention improves the continuity and stability of operations and reduces the cost of large-scale production. The device can pre-curing the surface of the stringer area by area without waiting for overall curing, thus shortening the bonding production cycle. The support, power unit, flexible unit and other components are all modular structures, and damaged parts can be replaced individually without the need for overall scrapping, which greatly reduces maintenance costs. Through standardized flange components, it can be docked with mainstream industrial robots and can be quickly integrated into existing aerospace composite panel production lines without large-scale modification of the production line, thus adapting to the needs of batch and streamlined production.

[0067] The present invention also provides a method for pre-curing adhesive bonding of composite stringers, comprising the following steps:

[0068] S1: The robot moves the device to the stringer storage area. The power unit drives the flexible clamping unit to approach and flexibly clamp the stringer vertical plate. The heating temperature control unit adjusts the angle and extension length simultaneously to make the heating surface parallel to the flange.

[0069] S2: The robot moves along the preset path with the device and the clamped stringer to the bonding coordinates, and the pressing device and flexible clamping unit adapt to the flange height difference to ensure that the stringer and the skin are bonded without gaps.

[0070] S3: After the compressive force reaches the preset value, the heating temperature control unit starts infrared heating and heats and cures the adhesive area according to the set parameters. The temperature sensor controls the temperature in real time.

[0071] S4: Once a single area has been solidified, the robot slightly lifts the device, the pressure rollers separate from the stringer, and each unit is reset.

[0072] S5: The robot with the device moves along the stringer to the next bonding area, and repeats steps S2-S4 until all areas are pre-cured.

[0073] Those skilled in the art will readily understand that the above description is merely 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 scope of protection of the present invention.

Claims

1. A robot end effector for pre-curing adhesive bonding of composite stringers, characterized in that, include: The support (1) is rigidly connected to the end effector of the robot; Power units (2) are symmetrically arranged at both ends of the bearing seat (1). Each power unit (2) includes two sets of fixed frames (24). By outputting power, the two sets of fixed frames (24) are driven to move closer or further apart in the horizontal longitudinal direction. The fixed frame (24) includes an outer connecting rod (241) and an inner connecting rod (242). The flexible clamping unit (3) located at the lower end of the external connecting rod (241) includes a first flexible component and clamping wheels (32); the first flexible component absorbs the rigid collision kinetic energy, so that the two sets of clamping wheels (32) can flexibly clamp the side of the stringer vertical plate. The flexible clamping unit (4) located at the lower end of the inner connecting rod (242) includes a second flexible component and a clamping wheel (41); the second flexible component absorbs the rigid collision kinetic energy generated by the clamping wheel (41) pressing down, so that the clamping wheel (41) can flexibly clamp the stringer flange; The heating temperature control unit (5) is arranged horizontally, and its two ends are respectively horizontally hinged to the flexible pressing unit (4), including an external heating module (51) and a telescopic rod (52); The robot moves the device to the stringer storage area. The power unit (2) drives the flexible clamping unit (3) to approach the flexible clamping stringer vertical plate. The heating temperature control unit (5) adjusts the angle and extension length simultaneously to make the heating surface parallel to the flange. The robot moves the device and the clamped stringer to the bonding coordinates according to the preset path. The device is pressed down, and the flexible pressing unit (4) adapts to the flange height difference to ensure that the stringer and the skin are bonded without gaps. After the pressing force reaches the preset value, the heating temperature control unit (5) starts infrared heating and heats and cures the bonding area according to the set parameters. The temperature sensor controls the temperature in real time to complete the curing operation of the bonding area.

2. The robot end effector for pre-curing adhesive bonding of composite stringers according to claim 1, characterized in that, The first flexible component includes a first flexible support frame (31), a first guide rod (33), a first sliding plate (34), and a first spring (35); wherein, the first flexible support frame (31) is fixedly mounted on the lower end of the outer connecting rod (241); multiple sets of the first guide rod (33) are arranged in parallel, and the other end of the multiple sets of first guide rods (33) passes through the first flexible support frame (31) and is fixedly connected to the first sliding plate (34); the first sliding plate (34) is adapted to the inner cavity of the first flexible support frame (31) and slides linearly in the inner cavity of the first flexible support frame (31) along the horizontal longitudinal direction; the first spring (35) is sleeved on the first guide rod (33), one end of which is connected to the first sliding plate (34), and the other end is connected to the inner wall of the first flexible support frame (31); the clamping wheel (32) is arranged along the horizontal longitudinal direction, and its wheel frame is fixedly connected to one end of the multiple sets of first guide rods (33).

3. The robot end effector for pre-curing adhesive bonding of composite stringers according to claim 1, characterized in that, The flexible clamping unit (4) includes a second flexible component, a clamping wheel (41), and a connecting frame (42); the second flexible component includes a second flexible support frame (43), a second guide rod, a second sliding plate, and a second spring; wherein, the second flexible support frame (43) is fixedly installed at the lower end of the inner connecting rod (242), and sliding grooves (44) are symmetrically opened on both sides of its frame body; multiple second guide rods are arranged parallel to each other in the vertical direction, and their top and bottom are respectively fixedly connected to the top and bottom of the inner cavity of the second flexible support frame (43). The second sliding plate is sleeved on multiple second guide rods, allowing it to move up and down linearly along the second guide rods. Its two ends pass through the sliding groove (44) and are respectively connected to the connecting frame (42) and the heating temperature control unit (5). The second spring is sleeved on the second guide rod, with one end connected to the second sliding plate and the other end connected to the inner wall of the second flexible support frame (43). The connecting frame (42) is a right-angled triangle, with its vertical right-angled side fixedly connected to one end of the second sliding plate and its horizontal right-angled side fixedly connected to the pressure wheel (41) frame.

4. The robot end effector for pre-curing adhesive bonding of composite stringers according to claim 3, characterized in that, The infrared heating module (51) is provided in two sets along the horizontal direction, and its two ends are respectively connected to the other end of the second sliding plate through the hinge seat (53); one end of the telescopic rod (52) is fixedly installed in the heating module (51), and the other end is fixedly connected to the rocker arm of the hinge seat (53). When the rocker arm rotates in the horizontal direction, it drives the telescopic rod (52) to extend and retract, thereby performing angle adaptive adjustment so that the heating surface is always parallel to the flange; the temperature sensor is installed at the bottom of the bearing seat (1) to detect the temperature of the area to be bonded.

5. A robot end effector for pre-curing adhesive bonding of composite stringers according to any one of claims 1-4, characterized in that, The bearing seat (1) has an H-shaped structure, including a bearing plate (11), mounting plates (12) arranged symmetrically at both ends of the bearing plate (11) along the horizontal longitudinal direction, and connecting plates (13) fixedly connected at both ends of the longitudinal direction to the center of the end of the bearing plate (11) and the center of the inner side of the mounting plate (12), respectively; the connecting plates (13) are provided with clearance grooves (14) at both ends of the longitudinal direction to allow the power unit (2) to pass through the mounting bracket (24).

6. A robot end effector for pre-curing adhesive bonding of composite stringers according to claim 5, characterized in that, The power unit (2) also includes a drive assembly (21), a transmission assembly (22), and a linear displacement assembly (23).

7. A robot end effector for pre-curing adhesive bonding of composite stringers according to claim 6, characterized in that, The drive assembly (21) includes a motor (211) and a motor mounting frame (212); the mounting frame (212) is fixedly located at the center of the mounting plate (12), and the motor (211) is fixedly located at the top of the motor mounting frame (212), with its motor shaft passing through the top of the motor mounting frame (212) and connected to the transmission assembly (22).

8. A robot end effector for pre-curing adhesive bonding of composite stringers according to claim 7, characterized in that, The transmission assembly (22) includes a first bevel gear (221) and a second bevel gear (222); the first bevel gear (221) is fixedly mounted on the motor shaft of the motor (211); the second bevel gear (222) has two sets arranged vertically, and the two sets of second bevel gears (222) are symmetrically arranged on both sides of the first bevel gear (221), and both mesh with the first bevel gear (221); the linear displacement assembly (23) is used to drive the two sets of fixed frames (24) to move synchronously in a linear direction. It has two sets, which are symmetrically arranged at both ends of the motor mounting frame (212), including a guide rail (231), a slider (232), and a lead screw. The system includes a nut (233), a lead screw (234), and a bearing seat (235). The guide rail (231) is fixedly mounted on the bearing plate (11) along the horizontal longitudinal direction. The slider (232) is slidably mounted on the guide rail (231), and the lead screw nut (233) is fixedly mounted on its side. The lead screw (234) is threadedly connected to the lead screw nut (233), and one end is connected to the second bevel gear (222) through a coupling. The rotation of the second bevel gear (222) drives the lead screw (234) to rotate. The bearing seat (235) is vertically fixed at the end of the mounting plate (12), and it is rotatably connected to the other end of the lead screw (234).

9. A robot end effector for pre-curing adhesive bonding of composite stringers according to claim 8, characterized in that, The fixing frame (24) is a portal frame that spans across the mounting plate (12) and includes an outer connecting rod (241) and an inner connecting rod (242), the inner sides of which are fixedly connected to both sides of the slider (232).

10. A method for pre-curing adhesive bonding of composite stringers, implemented by the apparatus as described in any one of claims 1-9, characterized in that, Includes the following steps: S1: The robot moves the device to the stringer storage area. The power unit (2) drives the flexible clamping unit (3) to move closer and flexibly clamp the stringer vertical plate. The heating temperature control unit (5) adjusts the angle and extension length simultaneously to make the heating surface parallel to the flange. S2: The robot moves along the preset path with the device and the clamped stringer to the bonding coordinates, and the pressing device and the flexible pressing unit (4) adapt to the flange height difference to ensure that the stringer and the skin are bonded without gaps. S3: After the compressive force reaches the preset value, the heating temperature control unit (5) starts infrared heating and heats and cures the adhesive area according to the set parameters. The temperature sensor controls the temperature in real time. S4: Once a single area has been solidified, the robot slightly lifts the device, the pressure roller (41) separates from the stringer, and each unit is reset; S5: The robot with the device moves along the stringer to the next bonding area, and repeats steps S2-S4 until all areas are pre-cured.

Images