Unmanned aerial vehicle reconfigurable multi-functional landing gear

Abstract

The application relates to the technical field of unmanned aerial vehicle landing gears, and discloses a reconfigurable multifunctional landing gear of an unmanned aerial vehicle, which comprises a base and a supporting unit, wherein the supporting unit is composed of a plurality of reconfigurable closed-chain seven-link mechanisms which are uniformly distributed in a circumferential direction; the closed-chain seven-link mechanism is formed by sequentially connecting the first link to the seventh link through the first rotary joint to the seventh rotary joint; a driving motor and a reconfiguration motor are further arranged; the driving motor is used for driving the closed-chain seven-link mechanism to perform folding and unfolding movements; the reconfiguration motor is used for driving the rotation angle of the rotary joint in the mechanism so as to change the spatial configuration of the closed-chain seven-link mechanism. The closed-chain structure with multiple movement modes is formed by reconfiguring the joint, the structure has higher rigidity and carrying capacity, the load can be effectively dispersed, the deformation and vibration can be reduced, the stability and safety during the landing process of the unmanned aerial vehicle are remarkably improved, and the landing support and the object grabbing function are integrated in the same mechanism.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) landing gear technology, and more particularly to a reconfigurable multi-functional UAV landing gear. Background Technology

[0002] With the widespread application of drones in fields such as military reconnaissance, logistics delivery, agricultural plant protection, and emergency rescue, the performance requirements for drone landing gear are increasing.

[0003] Traditional fixed drone landing gear has a simple structure, but it has poor adaptability when landing on complex terrains such as slopes, sand, ditches, or uneven surfaces, which can easily lead to drones tipping over, being damaged, or failing to land stably. At the same time, most existing landing gears have only one function, which can only provide basic support and cushioning, and it is difficult to meet the needs of grasping objects, adapting to different landing environments, and performing multiple tasks.

[0004] While some adjustable or foldable landing gears have improved terrain adaptability by altering their structural form, their reconfiguration capabilities are limited, mode switching is inconvenient, and they typically cannot achieve active grabbing or multi-functional conversion during landing. Therefore, there is an urgent need to develop a UAV landing gear with multi-mode reconfiguration capabilities, adaptability to various complex terrains, and grabbing functionality, to realize significant engineering application value. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] In view of the problems existing in the current drone landing gear, the present invention is proposed.

[0007] Therefore, the purpose of this invention is to provide a reconfigurable multi-functional landing gear for unmanned aerial vehicles (UAVs).

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a base and a support unit disposed at the lower end of the base, the support unit being composed of multiple circumferentially evenly distributed fully reversible closed-loop seven-bar linkages; the closed-loop seven-bar linkage is a closed-loop kinematic chain formed by the first to the seventh linkages being pivotally connected end-to-end through the first to the seventh reversible joints, the third linkage of the closed-loop seven-bar linkage being fixedly connected to the base, and the end of the seventh linkage being provided with a foot for contacting the ground or a target object; the closed-loop seven-bar linkage is also provided with a drive motor and a reconfigurable motor, the drive motor being disposed between the first and second linkages for driving the... A closed-loop seven-bar linkage performs a retraction and extension motion. The reconfigurable motor is located between the fourth and fifth links and is used to drive the rotation angle of the rotating joints in the mechanism, thereby changing the spatial configuration of the closed-loop seven-bar linkage. The axes of the first and seventh rotating joints are parallel to each other. Except for the first and seventh rotating joints, the axes of any two adjacent rotating joints are spatially perpendicular. The distances between the axes of the second and third rotating joints, the third and fifth rotating joints, and the fifth and sixth rotating joints are all equal, and all are equal to the distance between the axes of the first and seventh rotating joints. .

[0009] As a preferred embodiment of the reconfigurable multi-functional landing gear for unmanned aerial vehicles (UAVs) described in this invention, when the drive motor drives the closed-chain seven-bar linkage to move to the initial turning angle, the geometric center points of the first to seventh rotating joints are located in the same plane, that is, the closed-chain seven-bar linkage is in a singular configuration and has two instantaneous degrees of freedom; by controlling the reconfigurable motor to rotate in the singular configuration, the closed-chain seven-bar linkage can switch between a high-altitude spatial configuration and a low-altitude flat configuration. In the high-altitude spatial configuration, the support unit performs terrain-adaptive take-off and landing driven by the drive motor; in the low-altitude flat configuration, the support unit grasps the target object through coordinated inward movement.

[0010] As a preferred embodiment of the reconfigurable multi-functional landing gear for unmanned aerial vehicles (UAVs) described in this invention, the first connecting rod is a square rod with a first through hole and a second through hole at both ends, the axes of which are parallel to each other and perpendicular to the axis of the first connecting rod; wherein, the second through hole is opened on both sides of the first through hole, the drive motor is fixedly connected to the first connecting rod through the first through hole on one side and the two second through holes, and the first connecting rod is pivotally connected to the seventh connecting rod through the first through hole on the other side to form a seventh rotating joint; The advantages of this preferred solution are that it integrates the drive motor and the joint pivot on the same rod, which simplifies the assembly structure and helps reduce the weight of the UAV. The fixed end of the motor is directly rigidly connected to the seventh joint of the closed chain mechanism, which shortens the force transmission path and improves the overall rigidity of the landing gear.

[0011] As a preferred embodiment of the reconfigurable multi-functional landing gear for unmanned aerial vehicles according to the present invention, the second link is a square block structure and is connected to the output shaft of the drive motor through a first connecting hole on one end face. The second link and the first link are pivotally connected to form a first rotating joint. The second link is pivotally connected to the third link through a third through hole at the end away from the first connecting hole, forming a second rotating joint.

[0012] As a preferred embodiment of the reconfigurable multi-functional landing gear for unmanned aerial vehicles (UAVs) described in this invention, the third link is connected to the third through hole of the second link through a fourth through hole and a first connecting groove at one end; the third link is fixedly connected to the base through a fifth through hole in the middle; and the third link is pivotally connected to the fourth link through a sixth through hole and a second connecting groove at the other end to form a third rotating joint.

[0013] As a preferred embodiment of the reconfigurable multi-functional landing gear for unmanned aerial vehicles (UAVs) described in this invention, the fourth link includes an upper bracket and a lower bracket that is fixedly connected to the upper bracket. The upper bracket is hollow inside for fixing and installing a reconfigurable motor, and has a motor wiring port at the bottom. The lower bracket is pivotally connected to the third link. The output end of the reconfigurable motor is drivenly connected to the fifth link, and the fourth link and the fifth link are pivotally connected to form a fourth rotating joint.

[0014] As a preferred embodiment of the reconfigurable multi-functional landing gear for unmanned aerial vehicles described in this invention, the fifth link is connected to the output shaft of the reconfigurable motor via a second connecting hole at one end, and the other end is pivotally connected to the sixth link to form a fifth rotating joint.

[0015] As a preferred embodiment of the reconfigurable multi-functional landing gear for unmanned aerial vehicles described in this invention, the sixth link is pivotally connected to the fifth link and the seventh link through tenth through holes with mutually perpendicular axes at both ends, forming the fifth rotation joint and the sixth rotation joint respectively. A third connecting groove is provided at the end of the sixth link near the fifth link. The beneficial effect of this preferred solution is that the sixth link is the key node for realizing spatial motion reversal, enabling the motion transmission direction to be reversed by 90° in space.

[0016] As a preferred embodiment of the reconfigurable multi-functional landing gear for unmanned aerial vehicles (UAVs) described in this invention, the seventh link is an L-shaped block structure, with a connecting shaft at one end and pivotally connected to the first link to form a seventh rotating joint, an eighth through hole and a fourth connecting groove at the middle bend, and pivotally connected to the sixth link to form a sixth rotating joint, and a foot at the other end for contacting the ground or a target object.

[0017] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention adopts a closed-chain reconfigurable mechanism as the supporting structure. Through the designed reconfigurable joints, a closed-chain structure with multiple motion modes is formed. Compared with traditional open-chain landing gear, the closed-chain structure of this invention has higher structural stiffness and load-bearing capacity, effectively distributing loads, reducing deformation and vibration, thereby significantly improving the stability and safety of the UAV during landing. Simultaneously, this invention integrates landing support and object grasping functions into the same mechanism, achieving multi-functional switching through different motion modes. This allows the landing gear to quickly adjust its attitude according to different terrain environments, significantly expanding the application range of UAVs in complex terrains. Furthermore, it eliminates the need for additional grasping devices, simplifying the overall structure, reducing the weight of the UAV, and improving mission execution efficiency. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the overall structure of a reconfigurable multi-functional landing gear for an unmanned aerial vehicle according to an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of a closed-chain seven-bar linkage structure for a reconfigurable multi-functional landing gear for an unmanned aerial vehicle (UAV) according to an embodiment of the present invention.

[0021] Figure 3 This is a schematic diagram of the base structure of a reconfigurable multi-functional landing gear for an unmanned aerial vehicle according to an embodiment of the present invention.

[0022] Figure 4 This is a schematic diagram of the first link structure of a reconfigurable multi-functional landing gear for an unmanned aerial vehicle according to an embodiment of the present invention.

[0023] Figure 5 This is a schematic diagram of the second link structure of a reconfigurable multi-functional landing gear for an unmanned aerial vehicle according to an embodiment of the present invention.

[0024] Figure 6This is a schematic diagram of the third link structure of a reconfigurable multi-functional landing gear for an unmanned aerial vehicle (UAV) according to an embodiment of the present invention.

[0025] Figure 7 This is a schematic diagram of the fourth link structure of a reconfigurable multi-functional landing gear for an unmanned aerial vehicle according to an embodiment of the present invention.

[0026] Figure 8 This is a schematic diagram of the upper support structure of the fourth link of a reconfigurable multi-functional landing gear for an unmanned aerial vehicle according to an embodiment of the present invention.

[0027] Figure 9 This is a schematic diagram of the lower support structure of the fourth link of a reconfigurable multi-functional landing gear for an unmanned aerial vehicle according to an embodiment of the present invention.

[0028] Figure 10 This is a schematic diagram of the fifth link structure of a reconfigurable multi-functional landing gear for an unmanned aerial vehicle (UAV) according to an embodiment of the present invention.

[0029] Figure 11 This is a schematic diagram of the sixth link structure of a reconfigurable multi-functional landing gear for an unmanned aerial vehicle (UAV) according to an embodiment of the present invention.

[0030] Figure 12 This is a schematic diagram of the seventh link structure of a reconfigurable multi-functional landing gear for an unmanned aerial vehicle (UAV) according to an embodiment of the present invention.

[0031] Figure 13 This is a diagram illustrating the spatial high-attitude configuration motion of a reconfigurable multi-functional landing gear for an unmanned aerial vehicle (UAV) according to an embodiment of the present invention.

[0032] Figure 14 This diagram illustrates the process of reconfiguring a reconfigurable multi-functional landing gear of an unmanned aerial vehicle (UAV) from a high-attitude spatial configuration to a flat, low-attitude configuration, according to one embodiment of the present invention.

[0033] Figure 15 This is a motion diagram of a flat, low-attitude configuration of a reconfigurable multi-functional landing gear for an unmanned aerial vehicle (UAV) according to an embodiment of the present invention.

[0034] Figure 16 This is a schematic diagram of two flat-ground take-off and landing modes of a reconfigurable multi-functional landing gear for an unmanned aerial vehicle (UAV) according to an embodiment of the present invention.

[0035] Figure 17 This is a schematic diagram of a ramp takeoff and landing mode of a reconfigurable multi-functional landing gear for an unmanned aerial vehicle (UAV) according to an embodiment of the present invention.

[0036] Figure 18 This is a schematic diagram of a space-grabbing mode for a reconfigurable multi-functional landing gear of an unmanned aerial vehicle (UAV) according to an embodiment of the present invention.

[0037] Figure 19 This is a schematic diagram of the planar grasping mode of a flat, low-profile configuration of a reconfigurable multi-functional landing gear for an unmanned aerial vehicle (UAV) according to an embodiment of the present invention.

[0038] Explanation of reference numerals in the attached drawings: 100, base; 101, first fixing hole; 102, second fixing hole; 200, support unit; 300, closed-loop seven-bar linkage; 301, first link; 301a, first through hole; 301b, second through hole; 302, second link; 302a, first connecting hole; 302b, third through hole; 302c, mating through hole; 303, third link; 303a, fourth through hole; 303b, first connecting groove; 303c, fifth through hole; 303d, sixth through hole; 303e, second connecting groove; 304, fourth link; 304a, upper bracket; 304b, lower bracket; 304c, motor wiring port; 304d, mounting lug; 304e 304f, seventh through hole; 304g, motor hole; 305, fifth link; 305a, second connecting hole; 305b, eighth through hole; 305c, ninth through hole; 306, sixth link; 306a, tenth through hole; 306b, third connecting groove; 307, seventh link; 307a, connecting shaft; 307b, eleventh through hole; 307c, fourth connecting groove; 307d, foot; 308, drive motor; 309, reconfigurable motor; 401, first rotary joint; 402, second rotary joint; 403, third rotary joint; 404, fourth rotary joint; 405, fifth rotary joint; 406, sixth rotary joint; 407, seventh rotary joint. Detailed Implementation

[0039] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0040] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0041] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0042] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0043] Reference Figure 1 In one embodiment of the present invention, a reconfigurable multi-functional landing gear for an unmanned aerial vehicle is provided, comprising: a base 100 and a support unit 200 disposed at the lower end of the base 100. The support unit 200 is composed of multiple circumferentially evenly distributed fully rotating joint reconfigurable closed-loop seven-bar linkages 300 (support legs). In this embodiment, the closed-loop seven-bar linkages 300 are preferably four in number, equidistantly disposed at the four corners of the lower end of the base 100 along the circumference, and have the same structure.

[0044] Furthermore, such as Figure 2 As shown, the closed-loop seven-bar linkage 300 is a closed-loop kinematic chain formed by the first link 301 to the seventh link 307 being pivotally connected end to end through the first rotary joint 401 to the seventh rotary joint 407, in order to ensure load-bearing rigidity and structural stability. The third link 303 of the closed-loop seven-bar linkage 300 is fixedly connected to the base 100, and the end of the seventh link 307 is provided with a foot 307d for contacting the ground or a target object.

[0045] The closed-loop seven-bar linkage 300 is also equipped with a drive motor 308 and a reconfigurable motor 309. The drive motor 308 is located between the first link 301 and the second link 302 and is used to drive the closed-loop seven-bar linkage 300 to perform retraction and extension movements, that is, to provide the main power for the support unit 200 to retract, extend, or swing. The reconfigurable motor 309 is located between the fourth link 304 and the fifth link 305 and is used to drive the rotation angle of the rotating joints in the mechanism, change the spatial phase angle inside the mechanism, and thus change the spatial configuration of the closed-loop seven-bar linkage 300. Based on the high rigidity characteristics of the closed-loop seven-bar linkage 300, the motor adopts a servo motor or servo motor with a power failure brake (holding brake). When the motor is powered off or needs to maintain the current position, the holding brake automatically locks the output shaft, so that the landing gear can still maintain the current attitude and bear the weight of the UAV in the power failure state.

[0046] Specifically, the axes of the first rotary joint 401 and the seventh rotary joint 407 are parallel to each other. Except for the first rotary joint 401 and the seventh rotary joint 407, the axes of any two adjacent rotary joints are spatially perpendicular to each other. The distances between the axes of the second rotary joint 402 and the third rotary joint 403, the distances between the axes of the third rotary joint 403 and the fifth rotary joint 405, and the distances between the axes of the fifth rotary joint 405 and the sixth rotary joint 406 are all equal, and all equal to the distance between the axes of the first rotary joint 401 and the seventh rotary joint 407. .

[0047] Preferably, when the drive motor 308 drives the closed-loop seven-bar linkage 300 to move to the initial rotation angle, that is, when the angle θ of the drive motor 308 is 0°, the geometric center points of the first rotation joint 401 to the seventh rotation joint 407 are located in the same plane, and the closed-loop seven-bar linkage 300 is in a position as shown in the figure. Figure 2 The singular configuration shown represents the default structural state of the mechanism, in which the closed-loop seven-bar linkage 300 has two instantaneous degrees of freedom. By controlling the rotation of the reconfigurable motor 309 in the singular configuration, the closed-loop seven-bar linkage 300 can switch between a high-altitude spatial configuration and a low-altitude flat configuration. In the high-altitude spatial configuration, the support unit 200 performs terrain-adaptive take-off and landing driven by the drive motor 308. In the low-altitude flat configuration, the support unit 200 grasps the target object through coordinated inward movement. The rotation angle of the two motors is ±90°.

[0048] Furthermore, refer to Figure 3 The base 100 is used to fix and connect to the fuselage of the drone. The base 100 is preferably a square plate structure. There are four sets of first fixing holes 101 at the four corners of its lower edge for fixing to the third link 303 in the closed chain seven-bar linkage 300. The two first fixing holes 101 in each set are of equal size. There is a set of four second fixing holes 102 in the middle of the base 100 located on the same circumference for assembling with the drone base. The base 100 and the drone can be connected by threads, using anti-loosening nuts or thread sealant. Cotter pins or fuses are set on the bolt heads to prevent loosening. A shock-absorbing rubber pad or silicone pad can also be set between the two to absorb the landing impact.

[0049] Furthermore, refer to Figure 4The first connecting rod 301 is a square rod with two first through holes 301a and two second through holes 301b at both ends, the axes of which are parallel to each other and perpendicular to the axis of the first connecting rod 301. The two second through holes 301b are respectively opened on both sides of the first through hole 301a. The drive motor 308 is fixedly connected to the first connecting rod 301 through the first through hole 301a and the two second through holes 301b on one side. The first through hole 301a on the other side serves as the shaft hole of the seventh rotating joint 407. The first connecting rod 301 is pivotally connected to the seventh connecting rod 307 through the first through hole 301a to form the seventh rotating joint 407. Preferably, the two first through holes 301a and the two second through holes 301b have the same diameter to ensure the coaxiality and positioning accuracy of the drive motor 308.

[0050] Reference Figure 5The second connecting rod 302 has a square block structure and is connected to the output shaft of the drive motor 308 through a first connecting hole 302a on one end face. The first connecting hole 302a is preferably D-shaped. The second connecting rod 302 and the first connecting rod 301 are pivotally connected to form a first rotating joint 401. The second connecting rod 302 is pivotally connected to the third connecting rod 303 through a third through hole 302b on the end away from the first connecting hole 302a, forming a second rotating joint 402. That is, the first connecting hole 302a is provided on the lower side of the front end face of the second connecting rod 302, and a mating through hole is also provided on the same side end face as the first connecting hole 302a. 302c, which mates with the through hole on the output shaft of the drive motor 308, is used to axially lock the second connecting rod 302 to the output shaft of the drive motor 308 using fasteners, preventing loosening during operation. The output shaft of the motor can rotate freely with respect to the housing, meaning the first connecting rod 301 and the second connecting rod 302 can rotate freely. When the drive motor 308 rotates, it drives the second connecting rod 302 to rotate around the axis of the second rotating joint 402, thereby changing the angle of the second connecting rod 302 relative to the first connecting rod 301. The fastener can be a bolt and nut type; optionally, a shoulder bearing can also be provided on the motor output shaft. The connecting rod 302 bears axial force. Its front end (away from the motor body) is a D-shaped shaft section that mates with the D-shaped hole of the second connecting rod 302. Its rear end (closer to the motor body) is a large-diameter shoulder. The D-shaped hole of the second connecting rod 302 fits onto the D-shaped shaft section, with one end face abutting against the shoulder. Threadlocker can be applied to the screw to prevent loosening. A third through hole 302b is provided on the side of the front end face of the second connecting rod 302. A pivot joint 402 is formed by connecting the second connecting rod 302 and the third connecting rod 303 through the third through hole 302b. This pivot joint can be a bolt and flange bearing assembly, with a gasket assisting axial positioning and a nut for tightening. Alternatively, the pivot can be made by pressing rolling bearings into the through holes connecting the two connecting rods. A precision stepped bolt with a shoulder is used as the pivot, with its smooth shaft passing through the inner rings of the two bearings. The bolt head abuts against the end face of the inner ring of one bearing. At the other end of the bolt, a limiting spacer is fitted. The length of the spacer is equal to or slightly greater than the total width of the inner rings of the two bearings, so that the two ends of the spacer abut against the bolt head and the end face of the inner ring of the other bearing, respectively. An anti-loosening nut is screwed into the outside of the spacer. The clamping force generated by tightening the nut is transmitted to the bolt head through the spacer and does not act on the internal raceway of the bearing. This ensures reliable axial positioning while ensuring that the bearing can rotate flexibly.

[0051] Reference Figure 6The third link 303 is a square block structure. The third link 303 is connected to the third through hole 302b of the second link 302 through a fourth through hole 303a and a first connecting groove 303b at one end. The third link 303 is fixedly connected to the base 100 through a fifth through hole 303c in the middle. The third link 303 is pivotally connected to the fourth link 304 through a sixth through hole 303d and a second connecting groove 303e at the other end to form a third rotating joint 403. The length of the third link 303 is greater than that of the second link 302 and the fourth link 304. The fourth through hole 303a, the fifth through hole 303c, and the sixth through hole 303d have the same diameter. A pivot connector is used through the fourth through hole 303a to connect the second connecting rod 302 and the third connecting rod 303 to form the second rotating joint 402. Fasteners are used to fix the third connecting rod 303 to the base 100 through the two middle fifth through holes 303c. A pivot connector is used through the right-side sixth through hole 303d to connect the third connecting rod 303 and the fourth connecting rod 304 to form the third rotating joint 403. The first connecting groove 303b and the second connecting groove 303e are slots used to prevent interference between the third connecting rod 303 and the second connecting rod 302 and the fourth connecting rod 304 during movement. The connecting grooves mentioned in this embodiment can be determined according to the maximum swing range under motor drive, ensuring that the connecting rods maintain a non-contact gap throughout the entire movement stroke. A safety gap of 0.5mm-2mm is reserved between the edge of each connecting groove and the corresponding connecting rod.

[0052] Reference Figures 7-9 The fourth link 304 serves as a support for the reconfigurable motor 309, comprising an upper support 304a and a lower support 304b that is fixedly connected to the upper support 304a. The upper support 304a is hollow inside for the fixed installation of the reconfigurable motor 309. Preferably, it is as follows: Figure 8 The cylindrical structure shown has a motor wiring port 304c at the bottom, mounting lugs 304d and mounting through holes 304e on both sides of the upper bracket 304a, and a motor hole 304g and four identical small through holes at the top. The reconfigurable motor 309 flange is installed inside the upper bracket 304a through these four small through holes. The lower bracket 304b is as follows. Figure 9The integrated square-disc structure shown has a seventh through hole 304f at its upper part. A pivot joint connects the third link 303 and the fourth link 304 through the seventh through hole 304f to form a third rotating joint 403. The bottom of the lower support 304b has mounting lugs 304d and mounting through holes 304e on both sides of the disc, which mate with the upper support 304a. Fasteners are used to fix the upper and lower supports together through the two mounting through holes 304e. The lower support 304b is pivotally connected to the third link 303. The output end of the reconfigurable motor 309 is connected to the fifth link 305. The fourth link 304 and the fifth link 305 are pivotally connected to form a fourth rotating joint 404. When the reconfigurable motor 309 rotates at angle δ, it drives the fifth link 305 to rotate, thereby driving the sixth link 306 and the seventh link 307 to move, and simultaneously causing the first link 301 and the second link 302 to swing.

[0053] Reference Figure 10 The fifth link 305 is a square block structure. It is connected to the output shaft of the reconfigurable motor 309 through a second connecting hole 305a at one end, and pivotally connected to the sixth link 306 at the other end to form the fifth rotary joint 405. Specifically, the second connecting hole 305a on the lower end face of the fifth link 305 is a D-shaped connecting hole. An eighth through hole 305b is provided on the lower side of its front end face, which mates with the through hole on the output shaft of the reconfigurable motor 309. The fifth link 305 is connected to the reconfigurable motor 309 through the eighth through hole 305b using fasteners. A ninth through hole 305c is provided on the upper side of the front end face of the fifth link 305. The fifth link 305 is connected to the sixth link 306 through the ninth through hole 305c using a pivot to form the sixth rotary joint 406, thus converting the rotational motion of the reconfigurable motor 309 into a spatial configuration change of the entire closed-loop seven-bar linkage 300.

[0054] Reference Figure 11 The sixth link 306 is a square block structure. It is pivotally connected to the fifth link 305 and the seventh link 307 through tenth through holes 306a at both ends, whose axes are perpendicular to each other, forming the fifth rotary joint 405 and the sixth rotary joint 406 respectively. Each tenth through hole 306a at both ends has the same diameter, achieving a 90° reversal of the motion transmission direction in three-dimensional space. A third connecting groove 306b is provided at the end of the sixth link 306 closest to the fifth link 305, which is used to prevent motion interference with the fifth link 305 during movement. Specifically, the fifth link 305 and the sixth link 306 are connected via a pivot joint through the tenth through hole 306a at one end of the sixth link 306 to form the fifth rotary joint 405, and the sixth link 306 and the seventh link 307 are connected via a pivot joint through the tenth through hole 306a at the other end to form the sixth rotary joint 406.

[0055] Reference Figure 12The seventh link 307 is an L-shaped block structure. One end is provided with a connecting shaft 307a, which is pivotally connected to the first link 301 to form a seventh rotation joint 407. The connecting shaft 307a is directly inserted into the first through hole 301a of the first link 301. Optionally, the connecting shaft 307a can be a stepped shaft structure with a shoulder at the root and a retaining spring groove at the end. The connecting shaft 307a passes through the first through hole 301a of the first link 301. The through hole and the middle section of the connecting shaft 307a form a clearance fit, allowing the seventh link 307 to rotate freely relative to the first link 301 around the axis of the connecting shaft 307a. The middle bend of the seventh link 307 is provided with an eleventh through hole 307b and a fourth connecting groove 307c. The seventh link 307 is pivotally connected to the sixth link 306 using a pivot member to form a sixth rotation joint 406. The fourth connecting groove 307c is used to avoid interference with the sixth link 306 during movement. The other end of the seventh link 307 is provided with a foot 307d for contacting the ground or target object. The foot 307d can be a hemispherical soft rubber pad made of flexible material. The material and internal structure of the foot 307d can also be designed according to the actual terrain. It is fixedly installed at the bottom end of the L-shaped structure. Alternatively, the lower end of the seventh link 307 and the foot 307d can be connected by a detachable structure, such as a threaded hole or quick-release interface. The foot 307d is fixed by screwing in, snapping, or screwing, and is used to buffer energy absorption and provide friction during landing.

[0056] Reference Figure 2 When all the links of the closed-loop seven-bar linkage 300 are in the same plane, that is, when the center points of all the rotating joints (revolute pairs) are in the same geometric plane, and the overall space enclosed by all the links is a plane, the closed-loop seven-bar linkage 300 of the support unit 200 is in a singular configuration. The mechanism has two degrees of freedom, namely the angle θ of the drive motor 308 and the angle δ of the reconfiguration motor 309. In other motion states, the mechanism has only one degree of freedom.

[0057] It should be noted that in the same closed-loop seven-bar linkage 300, by reconfiguring the drive of the motor 309, the center points of the first rotating joint 401 to the seventh rotating joint 407 can be moved from a spatial position to a coplanar position. Under the singular configuration of the coplanar position, the degree of freedom of the mechanism changes from 1 to 2, which can realize the rapid adjustment of the overall attitude of the support leg and the repositioning of the landing point of the foot 307d. Through the coordination between the support units 200, the adaptive take-off and landing and grasping functions of the rotary-wing UAV under different terrains can be realized.

[0058] The working principle of this invention is as follows: When the closed-loop seven-bar linkage 300 of the support unit 200 is in a singular configuration, the angle δ of the reconfigurable motor 309 remains unchanged. The angle θ of the drive motor 308 is controlled to rotate. When the drive motor 308 rotates, its output shaft drives the second link 302 to rotate, changing the angle θ of the second link 302 relative to the first link 301 and the third link 303. When the second link 302 rotates, it pushes and pulls the third link 303 through the second rotation joint 402. Since the third link 303 is fixed to the base 100, this is transformed into elastic deformation and spatial rotation of the entire closed-loop, thereby causing spatial displacement of the foot 307d at the end of the seventh link 307. This can achieve the following: Figure 13 The motion pattern of the high-orientation spatial configuration is shown; When the closed-loop seven-bar linkage 300 of the support unit 200 is in a singular configuration, the angle θ of the drive motor 308 remains constant. By controlling the angle δ of the reconfigurable motor 309 to rotate ±90°, the fifth link 305 and its pivotally connected sixth and seventh links 306 move. The fifth and sixth rotary joints 405 and 406 are subjected to force, which in turn pulls the component locked by the first and second links 301 and 302 through the seventh rotary joint 407. The component can only swing around the axis of the second rotary joint 402. At the same time, when the fourth link 304 is subjected to the reaction force of the fifth link 305, it will also make slight adjustments to its posture around the third rotary joint 403. Therefore, the mechanism can realize the mutual conversion between a high-position spatial configuration and a flat low-position configuration. Figure 14 As shown, after the mechanism configuration transformation is completed, in the flat low-profile configuration mode, the mechanism is in a flattened posture.

[0059] After completing the mode transformation from a high-altitude spatial configuration to a flat, low-altitude configuration, with the fixed reconfiguration motor 309 angle δ remaining unchanged, the following can be achieved by controlling the drive motor 308 angle θ: Figure 15 The flat, low-profile configuration of the mechanism shown allows for attitude changes within the same plane of motion. The output shaft of the drive motor 308 drives the first link 301 to rotate around the axis of the first rotating joint 401, and through closed-loop linkage, pushes the sixth link 306 and the seventh link 307 to move. The foot 307d begins to deviate from the initial plane and rises along a spatial curve trajectory. As the angle θ of the drive motor 308 further increases, the swing amplitude of the first link 301 increases, and the sixth link 306 and the seventh link 307 are further driven. The foot 307d continues to rise along the spatial trajectory and shifts inward or outward. When the drive motor 308 reaches its maximum rotation stroke, the foot 307d rises to its highest position, either fully retracted or swinging to its limit position, which is suitable for the UAV to avoid obstacles or complete grasping actions in low-lying spaces.

[0060] Through the coordinated movement of four closed-loop seven-bar linkages 300, the following can be achieved: Figures 16 to 17 The take-off and landing functions shown for different terrains can be achieved through the inward movement of the four supporting legs in a high-orientation configuration in space, such as... Figure 18 The grasping pattern is shown. Through the inward movement of the two mechanisms on the same side in a flat, low-profile configuration, the following can be achieved: Figure 19 The shown capture mode.

[0061] The multi-functional landing gear of the present invention also includes a drive control system, which includes a drive motor 308, a reconfigurable motor 309, a position feedback device, a detection element, and a controller. The drive motor 308 drives the landing gear to perform landing, support, or grabbing movements; the reconfigurable motor 309 is installed at the reconfigurable joint (fourth rotational joint 404) and drives the reconfigurable joint to rotate, enabling the landing gear to switch between different motion modes.

[0062] The position feedback device is a rotary encoder installed in the drive motor 308 and the reconfiguration motor 309. It is used to detect the angular position of the joint in real time and feed the position signal back to the controller to form a closed-loop control.

[0063] The detection elements also include force sensors and inertial measurement units (IMUs). The force sensors are located between the seventh link 307 and the foot 307d to detect the real-time contact force between each support leg and the ground or target object, and feed the force signal back to the control to assist in landing buffering or grab control. The IMU can be installed on the base 100 to detect the attitude angles (roll angle, pitch angle, yaw angle) and angular velocity of the landing gear as a whole, providing attitude data reference for mode switching and motion control. The IMU can also be installed on the fuselage of the UAV to interact with the landing gear controller via wired or wireless communication.

[0064] The controller, based on position feedback signals and detection element signals, controls the movement of drive motor 308 and reconfiguration motor 309 to achieve landing gear mode reconfiguration and multi-functional operation. During control, the controller can determine the target motion mode according to actual mission requirements, control reconfiguration motor 309 to drive the reconfiguration joint to the target position and lock it, and then control drive motor 308 to drive the landing gear to complete the corresponding movement. Specifically, the controller can preset multiple motion modes, including but not limited to landing mode, grab mode, and storage mode. When the UAV is in flight, the landing gear is in storage mode, with all support legs retracted to a minimum windward attitude to reduce flight drag. When the UAV is preparing to land, the controller, based on the fuselage attitude and altitude information fed back by the IMU, controls the drive motor 308 of each support leg to adjust independently, ensuring that each foot 307d matches the ground slope before contact. After the foot 307d contacts the ground, the force sensor detects the contact force signal, the controller determines that the support leg has landed, and controls its drive motor 308 to switch to buffer mode. The system allows the support legs to elastically retract under impact to absorb landing energy. When all four support leg force sensors detect effective contact force (force values ​​stable within a preset threshold range, which can be expert-set based on the actual scenario), the controller determines that landing is complete, locks all motor brakes, and enters support mode. When switching to grasping mode, the controller first confirms that the landing gear is in a non-load-bearing state, i.e., the drone has taken off or the fuselage is externally supported. Then, it controls the reconfiguration motor 309 to rotate to a flat, low-profile configuration and locks it. Finally, it coordinates the control of the drive motors 308 of each support leg to perform inward movement to grasp the object. If, during landing, the force sensor of a support leg detects an overload (force value exceeding the preset threshold range), the controller controls the drive motor 308 of that leg to rotate in the opposite direction to unload the load and prevent damage to the mechanism. If the force sensor of a support leg does not detect contact force after landing (suspended in mid-air), the controller restricts further movement of the other support legs to prevent excessive tilting of the fuselage.

[0065] Furthermore, the power and signal lines of the drive motor 308 and the reconfigurable motor 309 can be led out from the base 100 and laid along the surface of the third link 303 and the fourth link 304. Spiral cables or flexible cables are used at the rotation joints to adapt to the rotational movement of the joints. After the motor cables are gathered at the base 100, they are connected to the main control system of the UAV fuselage through aviation plugs to realize the quick assembly and disassembly of the landing gear assembly. Optionally, a cable fixing clip is provided at the motor cable routing port 304c of the fourth link 304 to prevent the cables from interfering with or rubbing against the moving parts.

[0066] It should be noted that the reconfigurable multi-functional landing gear for UAVs provided by this invention adopts a closed-chain reconfigurable mechanism as its supporting structure. Through the designed reconfigurable joints, a closed-chain structure with multiple motion modes is formed. Compared with traditional open-chain landing gear, the closed-chain structure of this invention has higher structural rigidity and load-bearing capacity, effectively distributing loads, reducing deformation and vibration, thereby significantly improving the stability and safety of UAVs during landing. Simultaneously, this invention integrates landing support and object grasping functions into the same mechanism, achieving multi-functional conversion through different motion modes. This allows the landing gear to quickly adjust its attitude according to different terrain environments, significantly expanding the application range of UAVs in complex terrains. Furthermore, it eliminates the need for additional grasping devices, simplifying the overall structure, reducing the weight of the UAV, and improving mission execution efficiency.

[0067] It is important to note that the constructions and arrangements of this application shown in several different exemplary embodiments are merely illustrative. Although only a few embodiments are described in detail in this disclosure, those who consult this disclosure will readily understand that many modifications are possible (e.g., changes in the size, dimensions, structure, shape, and proportions of various elements, as well as parameter values ​​(e.g., temperature, pressure, etc.), mounting arrangements, use of materials, color, orientation, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in this application). For example, an element shown as integrally formed may be composed of multiple parts or elements, the position of elements may be inverted or otherwise altered, and the nature or number or position of discrete elements may be changed or altered. Therefore, all such modifications are intended to be included within the scope of the invention. The order or sequence of any process or method steps may be changed or rearranged according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure described herein that performs the function, and not only structurally equivalent but also equivalent in structure. Other substitutions, modifications, alterations, and omissions may be made in the design, operation, and arrangement of the exemplary embodiments without departing from the scope of the invention. Therefore, the present invention is not limited to the specific embodiments, but extends to various modifications that still fall within the scope of the appended claims.

[0068] Furthermore, in order to provide a concise description of exemplary embodiments, not all features of actual embodiments (i.e., those features that are not relevant to the currently considered best mode for carrying out the invention, or those features that are not relevant to implementing the invention) may be omitted.

[0069] It should be understood that numerous specific implementation decisions can be made during the development of any practical implementation, such as in any engineering or design project. Such development efforts may be complex and time-consuming, but for those skilled in the art who benefit from this disclosure, the development effort will be a routine work of design, manufacturing, and production without requiring much experimentation.

[0070] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A reconfigurable multi-functional landing gear for unmanned aerial vehicles (UAVs), characterized in that, include: The base (100) and the support unit (200) disposed at the lower end of the base (100) are composed of multiple circumferentially evenly distributed fully reversible closed-loop seven-bar linkages (300); The closed-loop seven-bar linkage (300) is a closed-loop kinematic chain formed by the first link (301) to the seventh link (307) being pivotally connected end to end through the first rotary joint (401) to the seventh rotary joint (407). The third link (303) of the closed-loop seven-bar linkage (300) is fixedly connected to the base (100), and the end of the seventh link (307) is provided with a foot (307d) for contacting the ground or a target object. The closed-loop seven-bar linkage (300) is also provided with a drive motor (308) and a reconfiguration motor (309). The drive motor (308) is located between the first link (301) and the second link (302) and is used to drive the closed-loop seven-bar linkage (300) to perform retraction and extension movements. The reconfiguration motor (309) is located between the fourth link (304) and the fifth link (305) and is used to drive the rotation angle of the rotating joint in the mechanism to change the spatial configuration of the closed-loop seven-bar linkage (300). Among them, the axes of the first rotary joint (401) and the seventh rotary joint (407) are parallel to each other. Except for the first rotary joint (401) and the seventh rotary joint (407), the axes of any two adjacent rotary joints are perpendicular to each other in space. The distances between the axes of the second rotary joint (402) and the third rotary joint (403), the distances between the axes of the third rotary joint (403) and the fifth rotary joint (405), and the distances between the axes of the fifth rotary joint (405) and the sixth rotary joint (406) are all equal, and all are equal to the distance between the axes of the first rotary joint (401) and the seventh rotary joint (407). .

2. The reconfigurable multi-functional landing gear for a drone as described in claim 1, characterized in that, When the drive motor (308) drives the closed-chain seven-bar linkage (300) to move to the initial rotation angle, the geometric center points of the first rotation joint (401) to the seventh rotation joint (407) are located in the same plane, the closed-chain seven-bar linkage (300) is in a singular configuration, and the closed-chain seven-bar linkage (300) has two instantaneous degrees of freedom. By controlling the reconfigurable motor (309) to rotate in a singular configuration, the closed-chain seven-bar linkage (300) switches between a high-altitude spatial configuration and a low-altitude flat configuration. In the high-altitude spatial configuration, the support unit (200) performs terrain-adaptive take-off and landing by driving the drive motor (308). In the low-altitude flat configuration, the support unit (200) grasps the target object through coordinated inward movement.

3. The reconfigurable multi-functional landing gear for a drone as described in claim 1, characterized in that, The first connecting rod (301) is a square rod with a first through hole (301a) and a second through hole (301b) at both ends, which are parallel to each other and perpendicular to the axis of the first connecting rod (301). The second through hole (301b) is opened on both sides of the first through hole (301a). The drive motor (308) is fixedly connected to the first connecting rod (301) through the first through hole (301a) on one side and the two second through holes (301b). The first connecting rod (301) is pivotally connected to the seventh connecting rod (307) through the first through hole (301a) on the other side to form the seventh rotating joint (407).

4. The reconfigurable multi-functional landing gear for a drone as described in claim 3, characterized in that, The second connecting rod (302) is a square block structure and is connected to the output shaft of the drive motor (308) through a first connecting hole (302a) on one end face. The second connecting rod (302) and the first connecting rod (301) are pivotally connected to form a first rotating joint (401). The second link (302) is pivotally connected to the third link (303) through a third through hole (302b) at the end away from the first connecting hole (302a), forming a second rotating joint (402).

5. The reconfigurable multi-functional landing gear for a drone as described in claim 4, characterized in that, The third link (303) is connected to the third through hole (302b) of the second link (302) through a fourth through hole (303a) and a first connecting groove (303b) at one end; The third link (303) is fixedly connected to the base (100) through the fifth through hole (303c) opened in the middle; The third link (303) is pivotally connected to the fourth link (304) through the sixth through hole (303d) and the second connecting groove (303e) at the other end, forming a third rotating joint (403).

6. The reconfigurable multi-functional landing gear for a drone as described in claim 5, characterized in that, The fourth link (304) includes an upper bracket (304a) and a lower bracket (304b) that is fixedly connected to the upper bracket (304a). The upper bracket (304a) is hollow inside for fixing and installing the reconfigurable motor (309), and has a motor wiring port (304c) at the bottom. The lower bracket (304b) is pivotally connected to the third link (303). The output end of the reconfigurable motor (309) is connected to the fifth link (305) for transmission, and the fourth link (304) and the fifth link (305) are pivotally connected to form the fourth rotation joint (404).

7. The reconfigurable multi-functional landing gear for a drone as described in claim 6, characterized in that, The fifth link (305) is connected to the output shaft of the reconfigurable motor (309) through a second connecting hole (305a) at one end, and the other end is pivotally connected to the sixth link (306) to form the fifth rotating joint (405).

8. The reconfigurable multi-functional landing gear for a drone as described in claim 7, characterized in that, The sixth link (306) is pivotally connected to the fifth link (305) and the seventh link (307) through tenth through holes (306a) with mutually perpendicular axes at both ends, forming the fifth rotary joint (405) and the sixth rotary joint (406) respectively. The sixth link (306) has a third connecting groove (306b) at the end near the fifth link (305).

9. A reconfigurable multi-functional landing gear for an unmanned aerial vehicle as described in claim 8, characterized in that, The seventh link (307) is an L-shaped block structure. One end is provided with a connecting shaft (307a) and is pivotally connected to the first link (301) to form a seventh rotating joint (407). The middle bend is provided with an eighth through hole (305b) and a fourth connecting groove (307c), and is pivotally connected to the sixth link (306) to form a sixth rotating joint (406). The other end is provided with a foot (307d) for contacting the ground or a target object.

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