Empennage structure of flapping-wing robot

Abstract

The invention relates to an empennage structure of a flapping-wing robot, which comprises a yawing mechanism, a pitching mechanism and a connecting mechanism, the yawing mechanism comprises a yawing steering engine, a yawing steering engine rocker arm, a yawing rocker arm and a yawing control surface; the pitching mechanism comprises a pitching steering engine, a pitching steering engine rocker arm and a pitching surface; the connecting mechanism comprises a pitching steering engine fixing plate, an empennage surface plate and a fuselage. The pitching motion function of the empennage is achieved through the knuckle bearing and the connecting rod structure, the yawing motion function of the empennage is achieved through the flexible material, the steering engine rocker arm and the yawing rocker arm, the yawing structure and the pitching structure are combined through the empennage plane plate, and the whole empennage mechanism is formed. The yawing motion cannot be affected during pitching motion, decoupling of the pitching motion and the yawing motion is achieved, meanwhile, the yawing control steering engine and the pitching control steering engine are both installed on the fuselage, empennage structural parts are reduced, the loading capacity during empennage motion is reduced, and the beneficial effects of being compact in structure and high in adjusting capacity are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of flapping-wing aircraft, and specifically relates to a tail structure of a flapping-wing robot. Background Art

[0002] Currently, most of the aircrafts performing rescue operations are fixed-wing and multi-rotor. The horizontal takeoff and landing distance of fixed-wing aircrafts is relatively long, and the unstable airflow in the disaster area will have a greater impact on them, with low energy utilization rate, which limits their wide application. Multi-rotor robots are highly flexible, but have a low payload-to-self-weight ratio, low energy utilization rate, and short endurance time. However, with the development of aerodynamics theory, new technologies, new materials, and new electromechanical technologies, flapping-wing aircrafts have gradually come into view. Flapping-wing aircrafts have the advantages of low cost and high endurance, and can also adapt to complex airflow by adjusting the wings.

[0003] The wings and tails of birds in the animal kingdom are complex structures with multiple degrees of freedom. Due to material and technological limitations, most artificial flapping-wing robots are simplified mechanisms, and their wings can only meet the requirements of lift and thrust. For the turning motion of flapping-wing robots, it can only be achieved through the tail.

[0004] The functions that the tail needs to achieve are yaw motion and pitch motion. In the existing tail design structures, there are two common types. One type is that the tail is a single plane, and the two motions are achieved through roll and pitch. The realization and installation of roll motion are difficult. After being coupled with pitch motion, the motor control accuracy is high, and an algorithm is also required for decoupling. The other type is that the tail is two planes, with the horizontal plane achieving pitch motion and the vertical plane achieving yaw motion. This type of tail structure has low control accuracy for the motor and is easy to implement.

[0005] Chinese Patent CN 118270259 A discloses a flapping-wing aircraft with multi-domain motion capabilities, which involves an integrated tail structure with fixed pitch and yaw control surfaces, and cannot complete the combined motion of yaw motion and pitch motion simultaneously.

[0006] In the existing tail structures that can achieve independent pitch and yaw motions, they are all in a series layout. For example, a water-air amphibious bionic flapping-wing robot with chordal dual modes disclosed in Chinese Patent CN 119262358 A involves a simple series mechanism, placing one of the servo motors for motion on the tail motion mechanism, increasing the load of the other servo motor, and also increasing the mass of the tail structure and the inertia moment.

[0007] In addition, the motion of the existing tail structures generally adopts the form of direct motor drive. The tail structure driven directly by the motor will transfer all the impact loads received to the motor, which is easy to cause damage to the motor. Summary of the Invention

[0008] In order to overcome the deficiencies of the prior art, the present invention provides a tail wing structure for a flapping-wing robot. The present invention provides a tail wing structure with simple structure and flexible control, in which the pitch motion and yaw motion are completely independent, which not only simplifies the tail wing structure, reduces the weight, but also improves the driving efficiency.

[0009] The technical solution adopted by the present invention is as follows: A tail wing structure for a flapping-wing robot, the tail wing structure comprising a yaw mechanism, a pitch mechanism and a connecting mechanism, The yaw mechanism includes a yaw servo, a yaw servo rocker arm, a yaw rocker arm and a yaw rudder surface; The pitch mechanism includes a pitch servo, a pitch servo rocker arm and a pitch surface; The connecting mechanism includes a pitch servo fixing plate, a tail wing flat plate and a fuselage; The pitch servo is connected to the fuselage through the pitch servo fixing plate, the output shaft of the pitch servo is fixedly connected to the pitch servo rocker arm, the pitch servo rocker arm is matched with a first joint bearing, the first joint bearing is connected to a second joint bearing through a pitch connecting rod, the second joint bearing is matched with a first pitch connecting member, the first pitch connecting member is fixedly connected to the pitch surface, the pitch surface is simultaneously fixedly connected to a second pitch connecting member, and the second pitch connecting member is hinged to a third pitch connecting member through a pitch surface connecting shaft; The tail wing flat plate is fixedly connected to the fuselage, the yaw servo is fixedly connected to the tail wing flat plate, and the output end of the yaw servo is connected to the yaw servo rocker arm; a flexible connection is adopted between the yaw servo rocker arm and the yaw rocker arm; the yaw rocker arm is connected to the yaw rudder surface.

[0010] The setting of the joint bearing allows a little error in the vertical direction between the pitch servo rocker arm and the first pitch connecting member. During the flight of the flapping-wing robot, the instantaneous force received by the tail wing and a part of it is relatively high. Due to the limitations of materials and weight, the stiffness of the materials of the tail wing part is not very high and there is elastic deformation. The use of the joint bearing can reduce the influence brought by the elastic deformation.

[0011] Preferably, the yaw rudder surface is composed of carbon fiber tubes combined through corresponding yaw connecting members. The carbon fiber tubes include a first carbon fiber tube, a second carbon fiber tube and a third carbon fiber tube, and the yaw connecting members include a first yaw connecting member, a second yaw connecting member, a third yaw connecting member and a fourth yaw connecting member; The first yaw connecting member is respectively matched with the second pitch connecting member and the fourth yaw connecting member, the fourth yaw connecting member is matched with the first carbon fiber tube, the first carbon fiber tube is fixedly connected to the yaw rocker arm, the first carbon fiber tube is connected to the second carbon fiber tube through the second yaw connecting member, and the second carbon fiber tube is connected to the third carbon fiber tube through the third yaw connecting member.

[0012] Preferably, the yaw servo rocker arm is a straight rocker arm, and the flexible material is a flexible steel wire rope, including a first plastic-coated steel wire rope and a second plastic-coated steel wire rope, and the lengths of the first plastic-coated steel wire rope and the second plastic-coated steel wire rope are the same.

[0013] Preferably, one end of the flexible steel wire rope is connected to the yaw rocker arm, and the other end is connected to the straight rocker arm. The distance from the connection point of the straight rocker arm to the rotation center of the straight rocker arm is the same as the distance from the yaw rocker arm to the rotation center of the yaw rudder surface; the flexible steel wire rope also bypasses the pitch plane connection shaft, and a limiting shoulder is machined on the shaft of the pitch plane connection shaft.

[0014] When the flexible steel wire rope bypasses the pitch plane connection shaft and the carbon plate undergoes a pitching motion, the yaw rocker arm undergoes displacement. At this time, the bending point of the flexible steel wire rope approaches the axis of the connection shaft, and the length of the steel wire rope hardly changes before and after the pitching motion. The effective connection between the servo straight rocker arm and the yaw rocker arm is maintained. Within the upper and lower limits of the pitching motion, the flexible steel wire rope is always bent around the connection shaft, without affecting the occurrence of the yaw motion. In this way, the complete decoupling of the yaw motion and the pitching motion is achieved, without mutual influence. The setting of the limiting shoulder can limit the movement of the flexible steel wire rope on the shaft, ensuring that there is no interference during the sliding of the flexible steel wire rope on the shaft.

[0015] Preferably, the pitch servo is bolted to the body of the flapping-wing robot through a pitch servo fixing plate.

[0016] Preferably, the pitch servo rocker arm is fitted with a first joint bearing through bolts and sleeves.

[0017] Preferably, the first pitch connecting member is fixedly connected to the pitch plane through bolts, and the first pitch connecting member is perpendicular to the pitch plane.

[0018] Preferably, the pitch plane connection shaft is in interference fit with the second pitch connecting member, and the pitch plane connection shaft is in clearance fit with the third pitch connecting member. The axis of the pitch plane connection shaft is parallel to the wingspan horizontal plane.

[0019] Preferably, the first yaw connecting member and the second pitch connecting member are fitted through a sleeve and a bearing. The inner ring of the bearing is in interference fit with the sleeve, while the sleeve is in interference fit with the second pitch connecting member, and the outer ring of the bearing is in interference fit with the first yaw connecting member. During the occurrence of the yaw motion, dynamic and static separation can be achieved, and at the same time, the bearing can be fully positioned.

[0020] Preferably, the first yaw connecting member is provided with a through hole, and the first yaw connecting member is in interference fit with the fourth yaw connecting member through the through hole; the yaw rocker arm is fixedly connected to the first carbon fiber tube through bolts.

[0021] The beneficial effects of the present invention are as follows: 1. The present invention adopts a connecting rod drive, which can share the impact load and make the mechanism more stable; the motor output motion is transmitted to the tail structure through the connecting rod. The impact load received by the tail during flight is transmitted to the motor in the same plane as the connecting rod, and the impact not in the same plane as the connecting rod is transmitted to the fuselage, which can effectively avoid the impact during the movement and extend the life of the motor; 2. The pitch servo and yaw servo of the present invention are fixedly connected to the fuselage, which simplifies the tail structure, reduces the tail mass, reduces the inertial load on the motor, and improves the driving efficiency; 3. The pitch surface (pitch carbon plate) and yaw control surface of the present invention can be controlled independently, and the compound motion can be completed by controlling the servo alone. That is, the structural design of the present invention only needs to control the rotation angle of each motor, and there is no need to consider the mutual influence between the two motions, which greatly reduces the control accuracy requirements of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is an isometric structural schematic diagram of the present invention; Figure 2 It is a left structural schematic diagram of the present invention; Figure 3 It is a schematic diagram of the rear structure of the present invention; Figure 4 This is a schematic diagram of the structure of the present invention with a yaw angle of 0 degrees and a pitch angle of 30 degrees; Figure 5 This is a schematic diagram of the structure of the present invention with a yaw angle of 0 degrees and an elevation angle of 30 degrees; Figure 6 It is a schematic diagram of the structure of the present invention with a left yaw angle of 30 degrees and a pitch angle of 0 degrees; Figure 7 It is a schematic diagram of the structure of the present invention with a right yaw angle of 30 degrees and a pitch angle of 0 degrees; Figure 8 It is a schematic diagram of the structure of the present invention with a left yaw angle of 30 degrees and a pitch angle of 30 degrees; Figure 9 It is a schematic diagram of the structure of the present invention with a right yaw angle of 30 degrees and an elevation angle of 30 degrees. DETAILED DESCRIPTION

[0023] The technical scheme of the present invention is further specifically described below through examples, which are provided for the purpose of explaining the present invention, not for limiting the present invention. Based on the examples in this application, all other examples obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0024] Reference Figures 1 to 3 , a tail wing structure of a flapping-wing robot, the tail wing structure comprising a yaw mechanism, a pitch mechanism and a connection mechanism, The yaw mechanism includes a yaw servo 17, a yaw servo rocker arm 8, a yaw rocker arm 12, and a yaw control surface 11; a flexible connection is adopted between the yaw servo rocker arm 8 and the yaw rocker arm 12; The yaw control surface 11 is composed of carbon fiber tubes through corresponding yaw connectors. The carbon fiber tubes include a first carbon fiber tube 11-1, a second carbon fiber tube 11-2, and a third carbon fiber tube 11-3. The yaw connectors include a first yaw connector 13, a second yaw connector 19, a third yaw connector 22, and a fourth yaw connector 20; The yaw servo rocker arm 8 is a straight rocker arm. The flexible material is a flexible steel wire rope, including a first plastic-coated steel wire rope 9 and a second plastic-coated steel wire rope 14. The first plastic-coated steel wire rope 9 and the second plastic-coated steel wire rope 14 have the same length; The pitch mechanism includes a pitch servo 3, a pitch servo rocker arm 5, and a pitch surface (pitch carbon plate) 10; the pitch surface is a plane formed by the pitch carbon plate; The connection mechanism includes a pitch servo fixing plate 2, a tail wing flat plate 7, and a fuselage 1.

[0025] The pitch servo 3 is bolted to the fuselage 1 of the flapping-wing robot through the pitch servo fixing plate 2. The output shaft of the pitch servo 3 is fixedly connected to the pitch servo rocker arm 5. The pitch servo rocker arm 5 is matched with the first joint bearing 4 through bolts and sleeves. The first joint bearing 4 is connected to the second joint bearing 23 through a pitch connecting rod 6. The second joint bearing 23 is matched with the first pitch connector 18. Among them, the connection between the first pitch connector 18 and the pitch surface 10 is a bolted connection, and the first pitch connector 18 is perpendicular to the pitch surface 10. The advantage of the joint bearing is that it allows a little error between the pitch servo rocker arm 5 and the first pitch connector 18 in the vertical direction. During the flight of the flapping-wing robot, the instantaneous force on the tail wing and a part of it is relatively high. Due to material and weight limitations, the stiffness of the material of the tail wing part is not very high, and there is elastic deformation. Using the joint bearing can reduce the influence brought by the elastic deformation. The pitch surface 10 is also fixedly connected to the second pitch connector 21. One end of the second pitch connector 21 is processed with a through hole. The second pitch connector 21 and the third pitch connector 16 are hinged through a pitch surface connecting shaft 15. The pitch surface connecting shaft 15 has an interference fit with the second pitch connector 21 and a clearance fit with the third pitch connector 16, and the axis is parallel to the wingspan horizontal plane.

[0026] When the pitch servo 3 deflects, it drives the pitch servo rocker arm 5 to swing, and pushes or pulls the first pitch connector 18 through the pitch connecting rod 6 to rotate around the pitch surface connecting shaft 15, thereby completing the pitch movement of the pitch surface 10 of the tail wing module.

[0027] The tail fin flat plate 7 is fixedly connected to the fuselage 1. The yaw servo 17 is fixedly connected to the tail fin flat plate 7, and the output end of the yaw servo 17 is connected to the straight rocker arm 8. The first yaw connecting piece 13 and the second pitch connecting piece 21 are fitted through a sleeve and a bearing. The inner ring of the bearing is interference-fitted with the sleeve, and the sleeve is interference-fitted with the second pitch connecting piece 21, while the outer ring of the bearing is interference-fitted with the first yaw connecting piece 13. In this way, dynamic and static separation can be achieved during yaw movement, and at the same time, the bearing can be fully positioned and can bear the axial force generated during flight while rotating. A through hole is provided at one end of the first yaw connecting piece 13, and the first yaw connecting piece 13 is interference-fitted with the fourth yaw connecting piece 20 through the through hole. One end of the fourth yaw connecting piece 20 is fitted with the first carbon fiber tube 11-1. The yaw rocker arm 12 is fixedly connected to the first carbon fiber tube 11-1 by bolts. The other end of the first carbon fiber tube 11-1 is adhesively bonded to the second yaw connecting piece 19. The other end of the second yaw connecting piece 19 is bonded to the second carbon fiber tube 11-2. The other end of the second carbon fiber tube 11-2 is bonded to the third yaw connecting piece 22. After the other end of the third yaw connecting piece 22 is bonded to the third carbon fiber tube 11-3, the yaw rudder surface 11 is formed. The yaw rocker arm 12 and the straight rocker arm 8 are flexibly connected by flexible steel wires 9 and 14. One end of the steel wire is connected to the yaw rocker arm 12, and the other end is connected to the straight rocker arm 8. The distance from the connection point of the straight rocker arm to the rotation center of the rocker arm is the same as the distance from the yaw rocker arm to the rotation center of the rudder surface. The flexible steel wire also bypasses the pitch plane connection shaft 15. The flexible steel wire is bent at the pitch plane connection shaft 15. When the pitch plane moves, the flexible steel wire bends around the pitch plane connection shaft 15, and the change in the length of the steel wire is very small. The movement of the straight rocker arm 8 can still be stably transmitted to the yaw rocker arm 12. The flexible condition can ensure the transmission of movement at any angle. Even at the limit of pitch movement, the yaw movement can still proceed normally. The pitch plane connection shaft 15 is machined with a limiting shoulder. When the yaw movement occurs, it restricts the movement of the flexible steel wire in the direction perpendicular to the rotation axis, preventing the flexible steel wire from moving and causing transmission failure or mechanism jamming.

[0028] When the yaw servo 17 deflects, it drives the straight rocker arm 8 of the servo to rotate. One end of the straight rocker arm 8 of the servo pulls the flexible steel wire. The steel wire pulls the yaw rocker arm 12, driving the yaw rudder surface to rotate around the bearing axis. The two flexible steel wires drive the yaw rocker arm of the tail fin back and forth, and the yaw rudder surface swings, thus completing the yaw multi-surface movement of the tail fin module.

[0029] Among them, the flexible steel wire rope bypasses the pitch plane connection shaft and bends at the pitch member rotation shaft. When the pitch plane (carbon plate) undergoes pitch motion, the yaw rocker arm 12 displaces. At this time, the bending point of the flexible steel wire rope approaches the axis of the pitch plane connection shaft, and the length of the flexible steel wire rope hardly changes before and after the pitch motion. The effective connection between the servo one-shaped rocker arm and the yaw rocker arm is still maintained. Within the upper and lower limits of the pitch motion, the flexible steel wire rope always bends around the pitch plane connection shaft, without affecting the occurrence of the yaw motion. In this way, the complete decoupling of the yaw motion and the pitch motion is achieved, without mutual influence.

[0030] The shoulder processed on the pitch plane connection shaft of the present invention can limit the crosstalk of the flexible steel wire rope on the shaft, ensuring that there is no interference during the sliding process of the flexible steel wire rope on the shaft. Both the servo fixing plate 2 and the tail wing flat plate 7 are fixedly connected to the fuselage. The mass load of the servo is on the fuselage, reducing the tail wing components and reducing the mass, thereby improving the tail wing drive efficiency.

[0031] The state of the present invention at a yaw angle of 0 degrees and a pitch angle of 30 degrees is as Figure 4 shown. The state of the present invention at a yaw angle of 0 degrees and a pitch angle of 30 degrees is as Figure 5 shown. The state of the present invention at a left yaw angle of 30 degrees and a pitch angle of 0 degrees is as Figure 6 shown. The state of the present invention at a right yaw angle of 30 degrees and a pitch angle of 0 degrees is as Figure 7 shown. The state of the present invention at a left yaw angle of 30 degrees and a pitch angle of 30 degrees is as Figure 8 shown. The state of the present invention at a right yaw angle of 30 degrees and a pitch angle of 30 degrees is as Figure 9 shown. From Figures 4 to 9 it can be seen that when the yaw angle of the present invention is at any position between a left yaw angle of 30 degrees and a right yaw angle of 30 degrees, the pitch motion is not restricted and can move to any position between a pitch angle of 30 degrees and a pitch angle of 30 degrees. Similarly, when the pitch angle is at any position between a pitch angle of 30 degrees and a pitch angle of 30 degrees, the yaw motion is not affected either. The present invention has the characteristic of well achieving the complete decoupling of the yaw motion and the pitch motion.

[0032] The present invention uses a spherical plain bearing and a connecting rod structure to realize the pitch motion function of the tail wing, uses a flexible steel wire rope, a yaw servo rocker arm, and a yaw rocker arm to realize the yaw motion function of the tail wing, and combines the yaw mechanism and the pitch mechanism by using the tail wing flat plate to form an overall tail wing structure. When the present invention can achieve pitch motion, the yaw motion will not be affected, realizing the decoupling of the pitch action and the yaw action. At the same time, both the yaw servo and the pitch servo are installed on the fuselage, reducing the tail wing structural components and reducing the load force during the tail wing action, having the advantages of a compact structure and strong adjustment ability.

[0033] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the various embodiments of the present application.

Claims

1. A tail structure of a flapping-wing robot, characterized in that: The tail structure includes a yaw mechanism, a pitch mechanism and a connection mechanism. The yaw mechanism comprises a yaw servo, a yaw servo rocker arm, a yaw rocker arm and a yaw control surface; The pitch mechanism comprises a pitch servo, a pitch servo rocker arm and a pitch surface; The connecting mechanism comprises a pitch servo fixing plate, a tail plane plate and a fuselage; The pitch servo is connected to the fuselage through a pitch servo fixing plate, the output shaft of the pitch servo is fixedly connected to the pitch servo rocker arm, the pitch servo rocker arm cooperates with a first joint bearing, the first joint bearing is connected to a second joint bearing through a pitch connecting rod, the second joint bearing cooperates with a first pitch connecting piece, the first pitch connecting piece is fixedly connected to a pitch surface, the pitch surface is fixedly connected to a second pitch connecting piece at the same time, and the second pitch connecting piece is hinged to a third pitch connecting piece through a pitch surface connecting shaft; The tail plane plate is fixedly connected to the fuselage, the yaw servo is fixedly connected to the tail plane plate, the output end of the yaw servo is connected to the yaw servo rocker arm; the yaw servo rocker arm and the yaw rocker arm are flexibly connected; and the yaw rocker arm is connected to the yaw control surface.

2. The tail wing structure of the flapping-wing robot according to claim 1, characterized in that: The yaw control surface is composed of carbon fiber tubes combined through corresponding yaw connectors, the carbon fiber tubes include a first carbon fiber tube, a second carbon fiber tube and a third carbon fiber tube, and the yaw connectors include a first yaw connector, a second yaw connector, a third yaw connector and a fourth yaw connector; The first yaw connector cooperates with the second pitch connector and the fourth yaw connector respectively, the fourth yaw connector cooperates with the first carbon fiber tube, the first carbon fiber tube is fixedly connected to the yaw rocker arm, the first carbon fiber tube is connected to the second carbon fiber tube through the second yaw connector, and the second carbon fiber tube is connected to the third carbon fiber tube through the third yaw connector.

3. The tail wing structure of the flapping-wing robot according to claim 1, characterized in that: The yaw steering gear rocker arm is a straight rocker arm, and the flexible material is a flexible steel wire rope, including a first plastic-coated steel wire rope and a second plastic-coated steel wire rope, and the first plastic-coated steel wire rope and the second plastic-coated steel wire rope have the same length.

4. The tail wing structure of the flapping-wing robot according to claim 3, characterized in that: One end of the flexible steel wire rope is connected to the yaw rocker arm, and the other end is connected to the I-shaped rocker arm. The distance from the I-shaped rocker arm connection point to the I-shaped rocker arm rotation center is consistent with the distance from the yaw rocker arm to the yaw control surface rotation center. The flexible steel wire rope also bypasses the pitch surface connecting shaft, and a limited position shoulder is processed on the shaft of the pitch surface connecting shaft.

5. The tail wing structure of the flapping-wing robot according to claim 1, characterized in that: The pitch servo is bolted to the flapping-wing robot body via a pitch servo fixing plate.

6. The tail wing structure of the flapping-wing robot according to claim 1, characterized in that: The pitch servo rocker arm is matched with the first joint bearing through a bolt and a sleeve.

7. The tail wing structure of the flapping-wing robot according to claim 1, characterized in that: The first pitch connection member is fixedly connected to the pitch surface by bolts, and the first pitch connection member is perpendicular to the pitch surface.

8. The tail wing structure of the flapping-wing robot according to claim 1, characterized in that: The pitch surface connecting shaft and the second pitch connecting member are in interference fit, the pitch surface connecting shaft and the third pitch connecting member are in clearance fit, and the axis of the pitch surface connecting shaft is parallel to the wingspan horizontal plane.

9. The tail wing structure of the flapping-wing robot according to claim 1, characterized in that: The first yaw connection member and the second pitch connection member are matched through a sleeve and a bearing, the inner ring of the bearing is interference fit with the sleeve, the sleeve is interference fit with the second pitch connection member, and the outer ring of the bearing is interference fit with the first yaw connection member.

10. The tail wing structure of the flapping-wing robot according to claim 1, characterized in that: The first yaw connecting member is provided with a through hole, and the first yaw connecting member is interference-fitted with the fourth yaw connecting member through the through hole; the yaw rocker arm is fixedly connected to the first carbon fiber tube by bolts.

Images