A structure that actively changes the twist shape of an airfoil

Abstract

This invention discloses a structural scheme for actively altering the torsional shape of an airfoil, belonging to the field of variator aircraft structural design technology. Specifically, when the drive device rotates the gear screw, the gear screws on the upper and lower flanges generate axial forces in opposite directions, forming a couple that causes the wing spars of the torsional deformation section to deflect around the hinge point. The front and rear wing spars deflect upward and downward around the hinge point respectively, while the skin on the upper and lower surfaces of the airfoil restricts the distance between the front and rear spars, thus causing torsional deformation of the airfoil. The torsional deformation angle is measured by a cable displacement sensor, which measures the distance the gear screw on the wing spar moves relative to the nut after deformation. The deflection angles of the front and rear spars are calculated based on the height of the spar web, and then combined with the chordal distance between the front and rear spars to obtain the torsional shape of the airfoil. The structure for actively altering the torsional shape of the airfoil proposed in this invention effectively improves the roll maneuverability of the aircraft, improves the distribution of aerodynamic loads, and reduces the load at the wing root.

Description

Technical Field

[0001] This invention belongs to the field of variator aircraft structural design technology, specifically relating to a structure that actively changes the torsional shape of an airfoil. Background Technology

[0002] During flight, morphing aircraft actively alter their aerodynamic shape according to different surrounding environments, maintaining optimal flight performance under various conditions. Current research on morphing aircraft primarily focuses on modifying wing area, wingspan, wing chord length, wing sweep angle, and wing leading and trailing edge camber. To effectively improve wing roll maneuverability and enhance static aeroelasticity, researchers have conducted in-depth studies on wing torsional deformation technology.

[0003] Adjusting the wing's twist shape can improve the aircraft's roll maneuverability and effectively mitigate aileron reaction and static aeroelasticity. By altering the distribution of the wing's leading edge twist angle, it is possible to improve the wing's aerodynamic load distribution and reduce the wing root load, thereby effectively increasing the structure's service life. Furthermore, the combination of active wing torsional deformation and leading and trailing edge deflection increases the wing's deformation combinations.

[0004] This invention proposes a structure that actively changes the torsional shape of an airfoil. This structure can achieve active torsional deformation of the airfoil through differential deformation of the front and rear spars, effectively improving the roll maneuverability of the aircraft, improving the distribution of aerodynamic loads, reducing the load at the airfoil root, optimizing the aerodynamic characteristics of the airfoil, and increasing the service life of the aircraft structure. Summary of the Invention

[0005] This invention achieves active torsional deformation of the wing structure through differential deformation of the front and rear beams, effectively improving the aircraft's roll maneuverability, improving the distribution of aerodynamic loads, reducing the load at the wing root, and effectively increasing the service life of the aircraft structure.

[0006] This invention is implemented as follows.

[0007] A structure for actively changing the torsional shape of an airfoil, characterized in that the structure includes gear screws, nuts, stops, support blocks, a cable displacement sensor, and a drive device; the structure is as follows: a hinge point is set at a certain spanwise position of the front and rear spars of the airfoil; the section from the wing root to the hinge point is a fixed section; the section from the hinge point to the wingtip is a torsional deformation section; the web of the fixed section and the torsional deformation section are hinged by single and double lugs; the upper and lower edge strips on the left and right sides of the web are respectively connected by four gear screws; the thread direction of the upper edge strip gear screw is opposite to the thread direction of the lower edge strip gear screw.

[0008] When the drive unit rotates the gear screw, the gear screws on the upper and lower flanges will generate axial forces in opposite directions, forming a couple, which will cause the spar of the torsional deformation section to deflect around the hinge point. The front and rear spars of the wing deflect upward and downward around the hinge point, respectively. The skin on the upper and lower surfaces of the wing restricts the distance between the front and rear spar flanges to remain unchanged, causing the wing to undergo torsional deformation. The torsional deformation angle of the wing is measured by the distance the gear screw on the spar moves relative to the nut after deformation by the cable displacement sensors arranged on the front and rear spars. The deflection angle of the front and rear spars is calculated based on the height of the spar web, and then the torsional shape of the wing is obtained by combining the chordal distance between the front and rear spars.

[0009] The bottom surface of the cable displacement sensor is fixed to the web of the torsional deformation section of the spar, and the side surface is fixed to the lower edge strip of the torsional deformation section of the spar. The measuring head of the sensor is fixed to the side of the lower edge strip of the fixed section of the spar. When the wing is horizontal and without deflection, the measuring cable of the cable displacement sensor is stretched horizontally and taut. At this time, the sensor reading is l. i0 When the wing twists, the output value of the cable displacement sensor is l. i The displacement Δl of the gear screw i =l i -l i0 (i=1 represents the data for the front spar; i=2 represents the data for the rear spar); from The deflection angles of the front and rear spars can be calculated. (i=1 represents the data for the front wing sparb; i=2 represents the data for the rear wing sparb), and then the torsion angle at the span m of the wing sparb in the torsional deformation section can be calculated. Where h is the height of the beam web, m is the span of the wing beam in the torsional deformation section, and f is the chordal distance between the front and rear wing beams.

[0010] Furthermore, when the drive device rotates the gear screw, the gear screws of the upper and lower flanges are subjected to driving torque, generating axial forces in opposite directions in the threaded pair. The couple formed by these opposite axial forces causes the torsional deformation section of the wing spars to deflect around the hinge point, while the front and rear wing spars of the wing deflect upward and downward around the hinge point, respectively, causing the wing to undergo torsional deformation. Among these, replacing the broken upper and lower flanges with gear screws ensures the transmission of normal stress between the fixed section and the torsional deformation section. The web of the fixed section and the torsional deformation section of the wing spars is hinged by single and double lugs, ensuring the transmission of shear force.

[0011] When the front and rear spars deflect upward and downward around the hinge point respectively, the chordal distance at the corresponding positions of the spars before and after deflection remains unchanged due to the in-plane force of the skin, causing the wing to undergo torsional deformation. At the same time, due to the action of the ribs, the cross-sectional shape of the wing can still remain unchanged after deflection, maintaining the aerodynamic shape required for the wing profile.

[0012] Furthermore, the nut is fixed to the flange of the torsional deformation section wing beam, with the bottom surface of the nut flush with the beam cross-section; the support block is fixed to the flange of the fixed section wing beam, with the bottom surface of the support block flush with the beam cross-section; the gear screw passes through the circular through hole of the support block, the circular boss contacts the bottom surface of the support block, and the threaded section is adapted to the nut; the stop block is fixed to the flange of the fixed section wing beam, allowing the smooth end of the gear screw to extend into the circular recess of the stop block; wherein, the nut, the circular through hole on the support block, the gear screw, and the circular recess on the stop block are coaxial; when the gear screw rotates, the support block prevents the gear screw from axially displacing, and the stop block prevents the gear screw from axially displacing and radially swaying.

[0013] Furthermore, the bottom surface of the cable displacement sensor is attached to the web of the torsional deformation section spar, and the side is fixed to the lower edge strip of the torsional deformation section spar. The measuring head is fixed to the lower edge strip of the fixed section spar and is used to measure the movement distance of the gear screws on the front and rear beams relative to the nuts. The drive device includes a motor, a primary drive shaft, a secondary drive shaft, and a tertiary drive shaft. The motor and each stage of the drive shaft are mounted on the fixed section spar. After the motor starts, the four gear screws are synchronously subjected to the same driving torque through the drive shafts.

[0014] Furthermore, the gear screw is divided into six sections: the first section is a threaded section that is adapted to the nut; the second section is a cylindrical section; the third section is a circular boss, the top surface of which contacts the bottom surface of the support block; the fourth section is a cylindrical section; the fifth section is a gear, which is used to cooperate with the drive device to transmit force; and the sixth section is a cylindrical section, the end of which extends into the circular recess of the stop block.

[0015] Furthermore, the outer contour of the nut is a quadrangular prism, one side of the nut is fixedly connected to the web of the torsional deformation section wing beam, the adjacent side of the first side of the nut is fixedly connected to the upper and lower edge strips, the nut is adapted to the threaded section of the gear screw, and the thread direction of the nut at the upper and lower edge strips is opposite; the distance between the center of the threaded through hole and the adjacent side of the first side of the nut is x, and the distance between the threaded through hole and the first side of the nut is y.

[0016] Furthermore, the outer contour of the support block is a quadrangular prism. One side of the support block is fixedly connected to the web of the fixed section wing beam, and the adjacent side of the first side of the support block is fixedly connected to the upper and lower edge strips. A circular through hole is provided on the bottom surface of the support block, with its center located on the bottom surface. The distance between the hole and the adjacent side of the first side of the support block is x, and the distance between the hole and the first side of the support block is y. The diameter of the hole is adapted to the cylindrical section of the gear screw. The gear screw passes through the circular through hole, so that the circular boss of the gear screw contacts the bottom surface of the support block.

[0017] Furthermore, the outer contour of the stop block is the same as that of the support block. One side of the stop block is fixedly connected to the web of the fixed section wing beam. The adjacent side of the first side of the stop block is fixedly connected to the upper and lower edge strips. A circular recess is provided on one of its bottom surfaces. The distance between the center of the recess and the adjacent side of the first side of the stop block is x, and the distance between the recess and the first side of the stop block is y. The diameter is adapted to the cylindrical section of the gear screw, so that the smooth end of the gear screw can be inserted into the recess, which prevents the screw from axially displacing and from radially swaying.

[0018] Furthermore, each of the front and rear wing spars is equipped with a drive unit. Each drive unit consists of a motor, a primary drive shaft, a secondary drive shaft, and two tertiary drive shafts. After the motor starts, it transmits the driving torque to the primary drive shaft, which then transmits it to the secondary drive shaft through the meshing of the primary gear and the secondary input gear. The driving torque on the secondary drive shaft is transmitted to the two tertiary drive shafts through the meshing of the secondary output gear and the two tertiary input gears. The two tertiary drive shafts transmit the driving torque to the gear screw through the meshing of the tertiary output gear and the gear screw. All four gear screws are synchronously subjected to the same driving torque. The front and rear spars are driven in a coordinated manner. When the drive unit drives the front and rear wing spars to deflect upward and downward around the hinge point, respectively, the skin on the upper and lower surfaces of the wing restricts the distance between the front and rear spars' flanges to remain constant, causing the wing to undergo torsional deformation. The skin is connected to the front and rear spars through wing ribs.

[0019] The advantages of this invention compared to the prior art are as follows:

[0020] This invention achieves active torsional deformation of the wing structure through differential deformation of the front and rear beams, effectively improving the aircraft's roll maneuverability, improving the distribution of aerodynamic loads, reducing the load at the wing root, and effectively increasing the service life of the aircraft structure.

[0021] The structure proposed in this invention, which actively alters the twist shape of the wing, effectively improves the aircraft's roll maneuverability, enhances the distribution of aerodynamic loads, and reduces the load at the wing root. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of wing torsional deformation in a structure that actively changes the torsional shape of an airfoil according to the present invention;

[0023] Figure 2 This is a schematic diagram of the differential deflection of the front and rear spars in a structure for actively changing the torsional shape of an airfoil according to the present invention.

[0024] Figure 3 This is a schematic diagram of the connection between the fixed section and the torsional deformation section of the wing spars in a structure for actively changing the torsional shape of an airfoil according to the present invention;

[0025] Figure 4This is a schematic diagram of a gear screw in a structure for actively changing the torsional shape of an airfoil according to the present invention;

[0026] Figure 5 This is a schematic diagram of the support block installation in a structure for actively changing the torsional shape of an airfoil according to the present invention;

[0027] Figure 6 This is a schematic diagram of a support block in a structure for actively changing the torsional shape of an airfoil according to the present invention;

[0028] Figure 7 This is a schematic diagram of sensor measurement in a structure that actively changes the torsional shape of an airfoil according to the present invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the following examples provide a more detailed description of the invention. It should be noted that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention.

[0030] This invention proposes a structure for actively altering the torsional shape of an airfoil. This scheme is applicable to twin-spar airfoils. A hinge point is set at a spanwise position on the front and rear spars. The section from the wing root to the hinge point is a fixed section, and the section from the hinge point to the wingtip is a torsional deformation section. The webs of the fixed and torsional deformation sections are hinged via single and double lugs. The upper and lower edge strips on the left and right sides of the web are each connected by four gear screws. The thread direction of the upper edge strip gear screws is opposite to that of the lower edge strip gear screws. When the drive device rotates the gear screws, the gear screws of the upper and lower edge strips generate axial forces in opposite directions, forming a torque. This causes the spar of the torsional deformation section to deflect around the hinge point; the front and rear spars of the airfoil deflect upward and downward around the hinge point, respectively. The skin on the upper and lower surfaces of the airfoil restricts the distance between the front and rear spar edge strips to remain constant, causing the airfoil to undergo torsional deformation. Figure 2 As shown in the diagram, this design allows the wing to flexibly adjust its twist angle during flight as needed, optimizing the aircraft's maneuverability.

[0031] The structure of this invention mainly consists of a gear screw, a nut, a stop block, a support block, a rope displacement sensor, and a driving device, such as... Figure 3As shown. A nut is fixed to the flange of the torsional deformation section wing beam, with its bottom surface flush with the beam cross-section. A support block is fixed to the flange of the fixed section wing beam, with its bottom surface flush with the beam cross-section. A gear screw passes through a circular through-hole in the support block, with a circular boss contacting the bottom surface of the support block, and its threaded section fitting the nut. A stop block is fixed to the flange of the fixed section wing beam, allowing the smooth end of the gear screw to extend into the circular recess of the stop block. The nut, the circular through-hole on the support block, the gear screw, and the circular recess on the stop block are coaxial. When the gear screw rotates, the support block prevents axial displacement of the gear screw, and the stop block prevents axial displacement and radial oscillation of the gear screw. The pull-string displacement sensor consists of a pull-string displacement sensor and a pull-string displacement sensor. The bottom surface of the cable displacement sensor is attached to the web of the torsional deformation section spar, and the side is fixed to the lower edge strip of the torsional deformation section spar. The measuring head is fixed to the lower edge strip of the fixed section spar, and it is used to measure the movement distance of the gear screws on the front and rear beams relative to the nuts. The drive unit consists of a motor, a primary drive shaft, a secondary drive shaft, and a tertiary drive shaft. The motor and each stage of the drive shaft are mounted on the fixed section spar. After the motor starts, the four gear screws are synchronously subjected to the same driving torque through the drive shafts.

[0032] Gear screw, such as Figure 4 As shown, it is divided into six sections. The first section is a threaded section that fits with the nut; the second section is a cylindrical section; the third section is a circular boss, the top surface of which contacts the bottom surface of the support block; the fourth section is a cylindrical section; the fifth section is a gear, which is used to cooperate with the drive device to transmit force; the sixth section is a cylindrical section, the end of which extends into the circular recess of the stop block.

[0033] The nut's outer contour is a quadrangular prism. One side of the nut is fixed to the web of the torsional deformation section of the wing beam. The adjacent side of the first side of the nut is fixed to the upper and lower flanges. The nut is compatible with the threaded section of the gear screw, and the thread directions of the nut at the upper and lower flanges are opposite. The distance x between the center of the threaded through hole and the adjacent side of the first side of the nut, and the distance y between the center and the first side of the nut, are shown below. Figure 6 As shown.

[0034] The outer contour of the support block is a quadrangular prism. One side of the support block is fixedly connected to the web of the fixed section wing beam, and the adjacent side of the first side of the support block is fixedly connected to the upper and lower edge strips; for example... Figure 5 As shown. A circular through hole is provided on the bottom surface of the support block, with its center located on the bottom surface. The distance between the hole and an adjacent side of the support block is x, and the distance between the hole and another side of the support block is y. The diameter of the hole is adapted to the cylindrical section of the gear screw. The gear screw passes through the circular through hole, causing the circular boss of the gear screw to contact the bottom surface of the support block, as shown. Figure 6 As shown.

[0035] The outer contour of the stop block is the same as that of the support block. One side of the stop block is fixedly connected to the web of the fixed section wing beam. The adjacent side of the first side of the stop block is fixedly connected to the upper and lower edge strips. A circular recess is provided on one of its bottom surfaces. The distance between the center of the recess and the adjacent side of the first side of the stop block is x, and the distance between the recess and the first side is y. The diameter of the recess is adapted to the cylindrical section of the gear screw, so that the smooth end of the gear screw can extend into the recess, preventing both axial displacement and radial oscillation of the screw. Figure 6 As shown.

[0036] Each of the front and rear wing spars is equipped with a drive unit, each consisting of a motor, a primary drive shaft, a secondary drive shaft, and two tertiary drive shafts. After the motor starts, it transmits driving torque to the primary drive shaft, which then transmits it to the secondary drive shaft via the meshing of the primary gear and the secondary input gear. The driving torque from the secondary drive shaft is then transmitted to the two tertiary drive shafts via the meshing of the secondary output gear and the two tertiary input gears. The two tertiary drive shafts transmit driving torque to the gear screw via the meshing of the tertiary output gear and the gear screw. All four gear screws are simultaneously subjected to the same driving torque. The front and rear spars are driven in a coordinated manner. When the drive unit causes the front and rear wing spars to deflect upwards and downwards around the hinge point, respectively, the skin on the upper and lower surfaces of the wing restricts the distance between the front and rear spars' flanges, causing torsional deformation of the wing. The skin is connected to the front and rear spars via wing ribs.

[0037] The torsional deformation angle of the wing is measured by rope displacement sensors arranged on the front and rear spars. The distance the gear screw moves relative to the nut on the deformed spar is measured, and the deflection angles of the front and rear spars are calculated based on the height of the spar web. This, combined with the chordal distance between the front and rear spars, yields the torsional shape of the wing. The bottom surface of the rope displacement sensor is fixed to the web of the torsional deformation section of the spar, and the side surface is fixed to the lower edge strip of the torsional deformation section of the spar. The sensor's measuring head is fixed to the side of the lower edge strip of the fixed section of the spar. Figure 7 As shown, when the wing is horizontal and without deflection, the measuring rope of the cable displacement sensor is stretched horizontally and taut. At this time, the sensor reading is l. i0 When the wing twists, the output value of the cable displacement sensor is l. i The displacement Δl of the gear screw i =l i -l i0 (i=1 represents the data for the front spar; i=2 represents the data for the rear spar). From The deflection angles of the front and rear spars can be calculated. (i=1 represents the data for the front wing sparb; i=2 represents the data for the rear wing sparb), and then the torsion angle at the span m of the wing sparb in the torsional deformation section can be calculated. Where h is the height of the beam web, m is the span of the wing beam in the torsional deformation section, and f is the chordal distance between the front and rear wing beams.

[0038] The main working principle is as follows: When the drive device rotates the gear screw, the gear screws of the upper and lower flanges are subjected to driving torque, generating axial forces in opposite directions in the threaded pair. The torque formed by these opposite axial forces causes the torsional deformation section of the wing spars to deflect around the hinge point. The front and rear wing spars of the wing deflect upward and downward around the hinge point, respectively, causing the wing to undergo torsional deformation. Figure 1 As shown, replacing the broken upper and lower flanges with gear screws ensures the transfer of normal stress between the fixed section and the torsional deformation section; the webs of the fixed section and the torsional deformation section of the wing spars are hinged by single and double lugs to ensure the transfer of shear force. Furthermore, when the front and rear spars deflect upwards and downwards around the hinge points respectively, under the action of the in-plane forces of the skin, the chordal distance at the corresponding positions of the wing spars before and after deflection remains unchanged, causing the wing to undergo torsional deformation; simultaneously, due to the action of the ribs, the wing's cross-sectional shape remains unchanged after deflection, maintaining the aerodynamic shape required for the wing profile.

[0039] The following specific data examples illustrate the solution of the present invention.

[0040] In this embodiment, a twin-spar wing with airfoil NACA0012 is selected. The airfoil has a relative thickness of 12%, a chord length of 1500mm, and a spanwise length of 5000mm. The front spars are located at 25% of the airfoil chord length, and the rear spars are located at 65% of the airfoil chord length. A hinge point is set at 3000mm spanwise from the wing root, allowing the wing section 2000mm beyond the hinge point to undergo torsional deformation. The front and rear spars are I-beams with a flange thickness of 5mm, a flange width of 84mm, a web thickness of 4mm, and a web height h = 120mm.

[0041] Assuming the maximum bending moment at the spar hinge point is 10000 N·m during wing torsion, the bending moment borne by the front spar is 6000 N·m, and the bending moment borne by the rear spar is 4000 N·m. Assuming both the gear screw and nut are made of alloy steel with a strength of approximately 800 MPa, the thread lift angle of the thread pair is 2.5°, and the equivalent friction angle is 7°. The outer contour of the nut is a quadrangular prism of 20×36×24 mm, where 24 mm is the length in the height direction of the web, 36 mm is the length in the width direction of the flange, and 20 mm is the length in the direction of the gear screw. The inner diameter is 12 mm, the distance from the center of the inner hole to side 1 is x = 12 mm, and the distance to side 2 is y = 20 mm. A trapezoidal thread profile with a height of 1.5 mm, a pitch of 2 mm, and 10 thread turns are selected. The gear screw has a diameter of 12mm, a thread length of 50mm, a trapezoidal tooth profile with a height of 1.5mm, a pitch of 2mm, and 20 thread turns. A 20mm diameter boss with a thickness of 10mm is located 50mm from the thread section on the gear screw. 20mm from the boss is a standard spur gear with a pitch circle diameter of 20mm, a tooth thickness of 10mm, 20 teeth, and a module of 1. The length of the polished shaft after the gear is 20mm. The total length of the gear screw is 150mm. The stop and support blocks are both 20×36×24mm four-piece blocks. The prism has a length of 24mm in the height direction of the web, 36mm in the width direction of the flange, and 20mm in the gear screw direction. Side 1 is fixed to the flange, and side 2 is fixed to the web. On the bottom surface, with a point at a distance of x = 12mm from side 1 and y = 20mm from side 2 as the center, the stop block has a 12mm diameter and 5mm deep recess along the axis, and the support block has a 12mm diameter circular through hole along the axis. The nuts at the upper flange of the front and rear beams are threaded in the positive direction, and the nuts at the lower flange are threaded in the negative direction. The distance between the nut and the support block is 50mm, that is, the distance between the break points of the upper and lower flanges is 50mm. The fixed section wing beam and the torsional deformation section wing beam are hinged by a single and double lugs. The web of the fixed section wing beam has a single lug, while the web of the torsional deformation section wing beam has a double lug to ensure the transmission of shear force. Based on the allowable shear stress value, the diameter of the pin at the hinge is determined to be 12mm and the length to be 16mm. The distance between the center of the pin hole on the single lug beam and the end face of the fixed section wing beam is 25mm.

[0042] The bottom surface of the cable displacement sensor is fixed to the web of the torsional deformation section spar, and the side surface is fixed to the lower edge strip of the torsional deformation section spar. The axial distance between the cable outlet on the side and the nut is 100mm. The sensor's measuring head is fixed to the side of the lower edge strip of the fixed section spar, with an axial distance of 0 from the support block. When the wing is horizontal and without deflection, the value of the cable displacement sensor is l. i0 =150mm (i=1 represents the data of the front spar; i=2 represents the data of the rear spar), and the spar deflects upward in the positive direction.

[0043] In the cable displacement sensor, a torsion angle is set, and the value that the sensor should output after torsional deformation is calculated using a formula. In the current state, the output values ​​of the sensors on the front and rear wing spars are read to determine the driving state of the wing's drive system (positive drive, negative drive, or maintaining the current flight state). If the aircraft needs to change its flight state, the front and rear spars coordinate their drive. The drive system drives the motors on the front and rear spars, transmitting the driving torque to the gear screws through the first, second, and third stage transmission shafts. All four gear screws are simultaneously subjected to the same driving torque. The front and rear wing spars deflect upwards and downwards around the hinge point, respectively. Simultaneously, the cable displacement sensor measures the distance the gear screws move relative to the nut. When the output values ​​of the cable displacement sensors on the front and rear wing spars are equal to the set output displacement, the wing completes torsional deformation.

[0044] To increase the fixed area, the support block, stop block, and nut all adopt a quadrangular prism structure. At the same time, the broken upper and lower edge strips are replaced by gear screws to ensure the transmission of normal stress, while the web plates of the fixed section and the torsional deformation section are hinged by single and double ears to ensure the transmission of shear force.

[0045] The skin is connected to the front and rear spars via ribs, and the chord length at the corresponding position of the spars does not change after the front and rear spars deflect. At the same time, constrained by the ribs, the cross-sectional shape of the wing remains unchanged after deflection, ensuring the required aerodynamic shape of the wing section.

[0046] This structural design allows the wing to flexibly adjust its twist angle during flight as needed, thereby optimizing the aircraft's maneuverability.

[0047] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of the present invention, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A structure for actively changing the torsional shape of an airfoil, characterized in that, The structure includes a gear screw, a nut, a stop block, a support block, a rope displacement sensor, and a drive device; a hinge point is set at a certain spanwise position of the front and rear spars of the wing; the section from the wing root to the hinge point is a fixed section, and the section from the hinge point to the wingtip is a torsional deformation section; the web of the fixed section and the torsional deformation section are hinged by single and double lugs; the upper and lower edge strips on the left and right sides of the web are respectively connected by four gear screws; the thread direction of the upper edge strip gear screw is opposite to the thread direction of the lower edge strip gear screw. When the drive unit drives the gear screw to rotate, the gear screws of the upper and lower flanges will generate axial forces in opposite directions, forming a couple, which will cause the wing spars of the torsional deformation section to deflect around the hinge point; while the front and rear wing spars of the wing deflect upward and downward around the hinge point respectively, and the skin of the upper and lower surfaces of the wing restricts the distance between the front and rear wing flanges to remain unchanged, causing the wing to undergo torsional deformation. The torsional deformation angle of the wing is measured by the displacement sensors of the ropes arranged on the front and rear spars. The distance of movement of the gear screw on the spar relative to the nut after deformation is obtained. The deflection angle of the front and rear spars is calculated based on the height of the spar web. The torsional shape of the wing is obtained by combining the chordal distance between the front and rear spars. The bottom surface of the cable displacement sensor is fixed to the web of the torsional deformation section spar, the side surface is fixed to the lower edge strip of the torsional deformation section spar, and the measuring head of the sensor is fixed to the side of the lower edge strip of the fixed section spar. When the wing is horizontal and without deflection, the measuring cable of the cable displacement sensor is stretched horizontally and taut. At this time, the sensor reading is l. i0 When the wing twists, the output value of the cable displacement sensor is l. i The displacement Δl of the gear screw i =l i -l i0 i=1 represents the data for the front wing spar; i=2 represents the data for the rear wing spar. Depend on The deflection angles of the front and rear spars can be calculated. i=1 represents the data for the front wing sparb; i=2 represents the data for the rear wing sparb, from which the torsion angle at the span m of the wing sparb in the torsional deformation section can be calculated. Where h is the height of the beam web, m is the span of the wing beam in the torsional deformation section, and f is the chordal distance between the front and rear wing beams.

2. The structure for actively changing the torsional shape of an airfoil according to claim 1, characterized in that, When the drive device rotates the gear screw, the gear screws of the upper and lower flanges are subjected to driving torque, generating axial forces in opposite directions in the threaded pair. The couple formed by these opposing axial forces causes the torsional deformation section of the wing spars to deflect around the hinge point. The front and rear wing spars of the wing deflect upward and downward around the hinge point, respectively, causing the wing to undergo torsional deformation. The replacement of the broken upper and lower flanges with gear screws ensures the transmission of normal stress between the fixed section and the torsional deformation section. The web of the fixed section and the torsional deformation section of the wing spars are hinged by single and double lugs, ensuring the transmission of shear force. When the front and rear spars deflect upward and downward around the hinge point respectively, the chordal distance at the corresponding positions of the spars before and after deflection remains unchanged due to the in-plane force of the skin, causing the wing to undergo torsional deformation. At the same time, due to the action of the ribs, the cross-sectional shape of the wing can still remain unchanged after deflection, maintaining the aerodynamic shape required for the wing profile.

3. The structure for actively changing the torsional shape of an airfoil according to claim 1, characterized in that, The nut is fixed to the flange of the torsional deformation section wing beam, with its bottom surface flush with the beam cross-section. The support block is fixed to the flange of the fixed section wing beam, with its bottom surface flush with the beam cross-section. The gear screw passes through the circular through hole of the support block, with its circular boss contacting the bottom surface of the support block, and its threaded section fitting the nut. The stop block is fixed to the flange of the fixed section wing beam, allowing the smooth end of the gear screw to extend into the circular recess of the stop block. The nut, the circular through hole on the support block, the gear screw, and the circular recess on the stop block are coaxial. When the gear screw rotates, the support block prevents axial displacement of the gear screw, and the stop block prevents axial displacement and radial sway of the gear screw.

4. The structure for actively changing the torsional shape of an airfoil according to claim 1, characterized in that, The bottom surface of the cable displacement sensor is attached to the web of the torsional deformation section spar, and the side is fixed to the lower edge strip of the torsional deformation section spar. The measuring head is fixed to the lower edge strip of the fixed section spar and is used to measure the movement distance of the gear screws on the front and rear beams relative to the nuts. The drive device includes a motor, a primary drive shaft, a secondary drive shaft, and a tertiary drive shaft. The motor and each stage of the drive shaft are mounted on the fixed section spar. After the motor starts, the four gear screws are synchronously subjected to the same driving torque through the drive shafts.

5. The structure for actively changing the torsional shape of an airfoil according to claim 1, characterized in that, The gear screw is divided into six sections: the first section is a threaded section that fits with the nut; the second section is a cylindrical section; the third section is a circular boss, the top surface of which contacts the bottom surface of the support block; the fourth section is a cylindrical section; the fifth section is a gear, which is used to cooperate with the drive device to transmit force; and the sixth section is a cylindrical section, the end of which extends into the circular recess of the stop block.

6. The structure for actively changing the torsional shape of an airfoil according to claim 1, characterized in that, The outer contour of the nut is a quadrangular prism. One side of the nut is fixedly connected to the web of the torsional deformation section wing beam. The adjacent side of the first side of the nut is fixedly connected to the upper and lower flanges. The nut is adapted to the threaded section of the gear screw, and the thread direction of the nut at the upper and lower flanges is opposite. The distance between the center of the threaded through hole and the adjacent side of the first side of the nut is x, and the distance between the threaded through hole and the first side of the nut is y.

7. The structure for actively changing the torsional shape of an airfoil according to claim 1, characterized in that, The outer contour of the support block is a quadrangular prism. One side of the support block is fixedly connected to the web of the fixed section wing beam, and the adjacent side of the first side of the support block is fixedly connected to the upper and lower edge strips. A circular through hole is provided on the bottom surface of the support block, with its center located on the bottom surface. The distance between the hole and the adjacent side of the first side of the support block is x, and the distance between the hole and the first side of the support block is y. The diameter of the hole is adapted to the cylindrical section of the gear screw. The gear screw passes through the circular through hole, so that the circular boss of the gear screw contacts the bottom surface of the support block.

8. The structure for actively changing the torsional shape of an airfoil according to claim 1, characterized in that, The outer contour of the stop block is the same as that of the support block. One side of the stop block is fixedly connected to the web of the fixed section wing beam. The adjacent side of the first side of the stop block is fixedly connected to the upper and lower edge strips. A circular recess is provided on one of its bottom surfaces. The distance between the center of the recess and the adjacent side of the first side of the stop block is x, and the distance between the recess and the first side of the stop block is y. The diameter is adapted to the cylindrical section of the gear screw, so that the smooth end of the gear screw can be inserted into the recess, which prevents the screw from axial displacement and radial oscillation.

9. The structure for actively changing the torsional shape of an airfoil according to claim 1, characterized in that, Each of the front and rear wing spars is equipped with a drive unit, which consists of a motor, a primary drive shaft, a secondary drive shaft, and two tertiary drive shafts. After the motor starts, it transmits the driving torque to the primary drive shaft, which then transmits it to the secondary drive shaft through the meshing of the primary gear and the secondary input gear. The driving torque of the secondary drive shaft is then transmitted to the two tertiary drive shafts through the meshing of the secondary output gear and the two tertiary input gears. The two tertiary drive shafts transmit the driving torque to the gear screw through the meshing of the tertiary output gear and the gear screw. All four gear screws are synchronously subjected to the same driving torque. The front and rear wing spars are driven in a coordinated manner. When the drive unit drives the front and rear wing spars to deflect up and down around the hinge point, the skin on the upper and lower surfaces of the wing restricts the distance between the front and rear wing edge strips to remain unchanged, causing the wing to undergo torsional deformation. The skin is connected to the front and rear wing spars through the wing ribs.

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