A lightweight UAV landing gear based on SMA locking and releasing device

Abstract

The present invention relates to the technical field of drone landing gear, and in particular to a lightweight drone landing gear based on an SMA locking and releasing device, comprising an unlocking cylindrical helical torsion spring, an SMA locking and releasing device, an oblique support rod, an upper support rod, and a lower support rod, wherein the bottom end of the lower support rod is connected to the landing gear wheel, and the top end of the lower support rod is hinged to one end of the upper support rod; the inner end of the oblique support rod is hinged to the middle part of the outer wall of the lower support rod, and the outer end of the oblique support rod is provided with the unlocking cylindrical helical torsion spring; the lower surface of the top end of the lower support rod is restricted from rotation by the left end of a locking pin; the locking pin is driven to move horizontally by an SMA locking and releasing device arranged in the belly of the aircraft. The present invention has a simple structure, a fast release speed, low power consumption, is reusable, and is easy to assemble; and can achieve lightweighting of the landing gear and the locking and releasing device.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicle (UAV) landing gear, and in particular to a lightweight UAV landing gear based on an SMA locking and releasing device. Background Art

[0002] Landing gear is a crucial device that supports the movement of drones and other aircraft during landing and gliding. With the continuous advancement of drone technology in recent years, the performance requirements for drone-related components have also been continuously increasing. As a key load-bearing component of a drone, the performance of the landing gear has a direct impact on its safety. While unaffected by the drone's own flight loads during flight, the landing gear plays a crucial role during the critical landing phase. When the drone is parked on the ground, the landing gear supports the drone's own weight, brakes and controls the drone during gliding, and absorbs and dissipates the impact energy generated by the drone and the ground during landing, thereby ensuring the drone's safety. Therefore, the landing gear must be lightweight, have a strong load-bearing capacity, and provide efficient cushioning and crash protection.

[0003] Currently, most drone landing gear consists of fixed or hydraulically retractable landing gear. Fixed landing gear, typically flat spring or skid-type, is primarily used on small and medium-sized, low-speed drones. This type of landing gear is non-retractable and remains exposed to the outside of the drone during flight, negatively impacting its aerodynamic shape and generating significant air resistance. Landing is also challenging, requiring only dedicated airfields or flat sandy terrain. Landing on rough terrain can easily cause deformation and bending due to impact, which can cause vibrations and rollover, potentially damaging the drone.

[0004] Currently, retractable landing gear is mostly wheeled, offering advantages such as a more stable landing, easier crosswind landings, and greater maneuverability. However, the commonly used wheeled landing gear is typically driven by a hydraulic system, requiring a supporting hydraulic device. This results in a complex structure and considerable weight. Wheeled landing gear systems include brakes, tires, wheels, shock absorbers, and other hydraulic equipment, as well as a retraction and deployment system, making them unsuitable for light UAVs.

[0005] Based on the above considerations, the present invention designs a lightweight UAV landing gear based on an SMA locking and releasing device. Summary of the Invention

[0006] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a lightweight UAV landing gear based on an SMA locking and releasing device. The landing gear adopts an SMA locking and releasing device to control the release of the landing gear, avoiding the complexity and bulkiness of the hydraulic drive device, and taking advantage of the strong adaptability of the wheeled landing gear. It can greatly improve the utilization rate of the UAV and at the same time more efficiently ensure the safety of the UAV during the landing process.

[0007] In order to achieve the purpose of the present invention, the technical solution adopted by the present invention is:

[0008] The present invention discloses a lightweight UAV landing gear based on an SMA locking and releasing device, comprising an unlocking cylindrical helical torsion spring, an SMA locking and releasing device, an oblique support rod, an upper support rod and a lower support rod, wherein the bottom end of the lower support rod is connected to the landing gear wheel, the top end of the lower support rod is hinged to one end of the upper support rod, and the other end of the upper support rod is hinged to the belly of the aircraft; the inner end of the oblique support rod is hinged to the middle part of the outer wall of the lower support rod, and the outer end of the oblique support rod is provided with the unlocking cylindrical helical torsion spring; the lower surface of the top end of the lower support rod is restricted in rotation by the left end of a locking pin; the locking pin is driven to move in a horizontal direction by an SMA locking and releasing device arranged in the belly of the aircraft.

[0009] The SMA locking and releasing device includes a cylindrical helical torsion spring, a rotary arm, a bayonet, a first compression spring, an SMA wire, a second compression spring, a bayonet seat and a locking seat, wherein the bayonet seat is a cylindrical structure, a bayonet slot for inserting the bayonet pin is provided at its right end, the first compression spring is connected between the inner end of the bayonet slot and the inner end of the bayonet pin, the SMA wire is sleeved on the inner side of the first compression spring, the inner end of the SMA wire is connected to the inner end face of the bayonet pin, and the outer end of the SMA wire passes through the inner end of the bayonet slot and is connected to the outside; the locking seat is a square structure arranged below the bayonet seat, and the locking bayonet is a cylindrical structure, the right end of which is shaped like a The locking member is a cylindrical structure with an outer diameter greater than that of the locking pin, and a limiting groove for sliding of the limiting portion is formed inside the locking seat, and a pin hole for passing the locking pin is provided at the left end of the limiting groove, and a second compression spring is connected between the left end of the limiting portion and the left end of the limiting groove; an opening communicating with the outside is formed at the top of the right end of the locking seat, and a limiting inclined surface is formed at the top of the outer end of the limiting portion; the right end of the swing arm is hinged to the belly of the machine and is driven to rotate clockwise by the cylindrical helical torsion spring, and an upper inclined surface and a lower inclined surface are formed at the left end of the swing arm, and the upper inclined surface and the lower inclined surface form an isosceles triangle structure.

[0010] The lower inclined surface has the same slope as the limiting inclined surface. When the bayonet is extended, the bottom end of the lower inclined surface is in tight contact with the bottom end of the limiting inclined surface; when the bayonet is retracted, the bottom end of the lower inclined surface is in tight contact with the top end of the limiting inclined surface.

[0011] The left end of the opening forms an opening inclined surface with the same slope as that of the limiting inclined surface.

[0012] The beneficial effects of the present invention are:

[0013] 1. The device has a simple structure, fast release speed, low power consumption, can be reused, and is easy to assemble, which can greatly reduce the cost of use.

[0014] 2. It can overcome the defects of traditional hydraulically driven landing gear devices such as complex structure, heavy weight, and large space occupied, and achieve lightweighting of the landing gear and locking and releasing device.

[0015] 3. The SMA locking and releasing device adopts a moving pair. Through the rotary arm, latch, locking latch and cylindrical helical compression spring, the requirements for the SMA wire's restoring force are further reduced. It can be unlocked by directly heating the SMA with electricity. At the same time, the power requirements are also reduced. Therefore, the internal power supply of the drone can be used. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 : A schematic diagram of a lightweight UAV landing gear based on an SMA locking and releasing device in the present invention, which mainly consists of landing gear support rods and an SMA locking and releasing device;

[0017] Figure 2 : A schematic diagram of the locking and releasing device and the landing gear support rod of a lightweight UAV landing gear based on an SMA locking and releasing device during normal flight of the UAV in the present invention;

[0018] Figure 3 : Schematic diagram of the process of unlocking the SMA locking release device and lowering the landing gear support rod when the UAV receives a landing mission;

[0019] Figure 4 : Schematic diagram of the SMA locking release device and the landing gear support rods when the drone is landing;

[0020] Figure 5 : Schematic diagram of the locking state of the SMA locking and releasing device in the present invention;

[0021] Figure 6 : Schematic diagram of the unlocking state of the SMA locking and releasing device in the present invention.

[0022] In the figure, 1 unlocking cylindrical helical torsion spring, 2 SMA locking release device, 3 oblique support rod, 4 upper support rod, 5 lower support rod, 6 landing gear wheel, 201 cylindrical helical torsion spring, 202 swing arm, 203 bayonet, 204 first compression spring, 205 SMA wire, 206 second compression spring, 207 locking bayonet, 208 bayonet seat, 209 locking seat, 210 bayonet slot, 211 limiting part, 212 limiting slot, 213 bayonet hole, 214 opening, 215 limiting inclined surface, 216 upper inclined surface, 217 lower inclined surface, 218 opening inclined surface. DETAILED DESCRIPTION

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0024] See also Figure 1-6 .

[0025] The present invention discloses a lightweight UAV landing gear based on an SMA locking and releasing device. Figure 1 As shown, it includes an unlocking cylindrical helical torsion spring 1, an SMA locking release device 2, an oblique support rod 3, an upper support rod 4 and a lower support rod 5. The bottom end of the lower support rod 5 is connected to the landing gear wheel 6, the top end of the lower support rod 5 is hinged to one end of the upper support rod 4, and the other end of the upper support rod 4 is hinged to the belly of the aircraft; the inner end of the oblique support rod 3 is hinged to the middle part of the outer wall of the lower support rod 5, and the outer end of the oblique support rod 3 is provided with the unlocking cylindrical helical torsion spring 1; the lower surface of the top end of the lower support rod 5 is restricted from rotating by the left end of the locking pin 207; the locking pin 207 is driven to move in the horizontal direction by the SMA locking release device 2 arranged in the belly of the aircraft. The locking pin 207 is driven by the principle of thermal contraction of the SMA wire to limit and unlock the landing gear. It has a simple structure, fast release speed, low power consumption, can be reused, and is easy to assemble, which can greatly reduce the cost of use. It can overcome the defects of traditional hydraulically driven landing gear devices such as complex structure, heavy weight, and large space occupied, and achieve lightweight landing gear and locking release device. The SMA locking release device adopts a moving pair, through the swing arm, pin, locking pin and cylindrical helical compression spring, the requirement for the restoring force of the SMA wire is further reduced. It can be unlocked by directly heating the SMA with electricity, and the requirement for power supply power is also reduced. Therefore, the internal power supply of the drone can be used.

[0026] Furthermore, the SMA locking and releasing device 2 includes a cylindrical helical torsion spring 201, a rotary arm 202, a bayonet 203, a first compression spring 204, an SMA wire 205, a second compression spring 206, a bayonet seat 208 and a locking seat 209. The bayonet seat 208 is a cylindrical structure, and a bayonet slot 210 is provided at its right end for inserting the bayonet 203. The first compression spring 204 is connected between the inner end of the bayonet slot 210 and the inner end of the bayonet 203. The SMA wire 205 is sleeved on the inner side of the first compression spring 204, and the inner end of the SMA wire 205 is connected to the inner end face of the bayonet 203. The outer end of the SMA wire 205 passes through the inner end of the bayonet slot 210 and is connected to the outside. The locking seat 209 is a square structure and is arranged below the bayonet seat 208. The locking bayonet 207 is a cylindrical structure. A limiting portion 211 is formed at the end, and the limiting portion 211 is a cylindrical structure with an outer diameter greater than the locking pin 207. A limiting groove 212 is formed inside the locking seat 209 for the limiting portion 211 to slide, and a pin hole 213 is provided at the left end of the limiting groove 212 for the locking pin 207 to pass through. The second compression spring 206 is connected between the left end of the limiting portion 211 and the left end of the limiting groove 212; an opening 214 communicating with the outside is formed at the top of the right end of the locking seat 209, and a limiting inclined surface 215 is formed at the top of the outer end of the limiting portion 211; the right end of the swing arm 202 is hinged to the belly of the machine and is driven to rotate clockwise by the cylindrical helical torsion spring 201, and an upper inclined surface 216 and a lower inclined surface 217 are formed at the left end of the swing arm 202, and the upper inclined surface 216 and the lower inclined surface 217 form an isosceles triangle structure.

[0027] The working principle of the SMA locking and releasing device 2 is as follows:

[0028] like Figure 2 The figure shows the state of the lightweight UAV landing gear during normal flight. When the UAV performs a normal flight mission, the upper support rod 4, the lower support rod 5 and the diagonal support rod 3 of the landing gear are retracted in the belly of the aircraft, and the locking pin 207 extends to the left to support the top and bottom of the lower support rod 5, thereby preventing the landing gear from being lowered; at this time, the state of the SMA locking release device 2 is as shown. Figure 5 As shown, the SMA wire 205 and the first compression spring 204 are in a normal state, the right end of the pin 203 extends to press the left end of the swing arm 202 to the lowest point, and the bottom end of the lower inclined surface 217 of the swing arm 202 is in tight contact with the bottom end of the limiting inclined surface 215. At this time, the left end of the locking pin 207 is in a state of extending the most to the left, and the second compression spring 206 is in a compressed state, thereby realizing that the locking pin 207 supports and limits the top bottom of the lower support rod 5.

[0029] like Figure 3As shown, the state of the lightweight UAV landing gear when the SMA locking release device is unlocked and the landing gear is lowered when the UAV receives the landing command, at this time the left end of the locking pin 207 moves to the right, so that the locking pin 207 releases the support limit with the bottom of the top end of the lower support rod 5, and the unlocked cylindrical helical torsion spring 1 drives the oblique support rod 3 to rotate counterclockwise, which in turn drives the lower support rod 5 hinged to the oblique support rod 3 to rotate counterclockwise and the upper support rod 4 to rotate clockwise. Figure 4 The landing gear is shown in the fully extended state; before the UAV performs a landing mission, the ground operator only needs to turn on the power switch of the SMA lock release device, the SMA wire 205 is energized and heated to shrink, and the SMA lock release device is unlocked, and the state is as shown Figure 6 When unlocking, the SMA wire 205 is energized, causing the temperature of the SMA wire 205 to rise after being energized. The SMA wire 205 contracts due to the heat, overcoming the work done by the first compression spring 204 and driving the bayonet 203 to move leftward along the bayonet slot 210. When the right end of the bayonet 203 moves to the upper inclined surface 216 at the left end of the swing arm 202, due to the action of the cylindrical helical torsion spring 201 at the right end of the swing arm 202, the left end of the swing arm 202 is driven to gradually rotate clockwise. At the same time, the lower inclined surface 217 also gradually moves upward along the limiting inclined surface 215 on the limiting portion 211. The locking bayonet 207 can also gradually move rightward along the limiting slot 212 under the restoring action of the second compression spring 206 until the bottom end of the lower inclined surface 217 is aligned with the limiting portion 211. When the top end of the limiting inclined surface 215 is in tight contact, the left end of the locking pin 207 and the support limit of the bottom end of the lower support rod 5 are released, and the SMA locking release device is unlocked; at this time, the SMA wire 205 is no longer energized, and the temperature of the SMA wire 205 drops after stopping being heated, and it returns to its original length. The pin 203 moves to the right under the elastic force of the first compression spring 204, and under the pressure of the pin 203, the swing arm 202 overcomes the torsional force of the cylindrical helical torsion spring 201 and rotates counterclockwise to push the locking pin 207. The locking pin 207 moves to the left under the action of the swing arm 202, overcoming the elastic force of the second compression spring 206. At this time, the SMA locking release device 1 returns to its initial state. Figure 5 shown.

[0030] Furthermore, in this embodiment, the slope of the lower inclined surface 217 is the same as that of the limiting inclined surface 215. When the pin 203 is extended, the bottom end of the lower inclined surface 217 is in tight contact with the bottom end of the limiting inclined surface 215; when the pin 203 is retracted, the bottom end of the lower inclined surface 217 is in tight contact with the top end of the limiting inclined surface 215, ensuring that when the support limit between the left end of the locking pin 207 and the top bottom of the lower support rod 5 is released, the lower inclined surface 207 and the limiting inclined surface 215 will not be completely separated. If they are completely separated, the locking pin 207 is no longer limited by the swing arm 202 and can move to the right end of the limiting groove 212 under the action of the second compression spring 206. When the SMA wire 205 is no longer energized, the locking pin 207 cannot be reset.

[0031] Furthermore, a reset slope 219 is formed at the bottom left end of the locking latch 207. The bottom end of the reset slope 219 is inclined to the lower right and matched with the top end of the lower support rod 5. When the UAV completes the landing mission, the landing gear is pushed in the retraction direction under human power. At this time, when the top end of the lower support rod 5 contacts the reset slope 219, the reset slope 219 is subjected to a force that generates a partial rightward component to move the locking latch 207 to the right end. After the lower support rod 5 passes over the locking latch 207, the swing arm 202 is manually pressed down. The lower slope 217 and the limit slope 215 interact with each other to push the locking latch 207 to the left and return to the locked position to prevent the lower support rod 5 from moving. At the same time, the latch 203 moves to the right under the action of the first compression spring 204, blocking the cantilever 202, and the entire locking mechanism is restored. Figure 5 The landing gear is in the locked state shown in the figure, and the retraction action of the landing gear can be completed so that the landing gear is hidden in the fuselage.

[0032] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's description and drawings, or any direct or indirect application in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A lightweight UAV landing gear based on an SMA locking and releasing device, characterized by: The invention comprises an unlocking cylindrical helical torsion spring (1), an SMA locking release device (2), an oblique support rod (3), an upper support rod (4) and a lower support rod (5), wherein the bottom end of the lower support rod (5) is connected to the landing gear wheel (6), the top end of the lower support rod (5) is hinged to one end of the upper support rod (4), and the other end of the upper support rod (4) is hinged to the inside of the aircraft belly; the inner end of the oblique support rod (3) is hinged to the middle part of the outer wall of the lower support rod (5), and the outer end of the oblique support rod (3) is provided with the unlocking cylindrical helical torsion spring (1); the lower surface of the top end of the lower support rod (5) is restricted from rotating by the left end of the locking pin (207); The locking pin (207) is driven to move in a horizontal direction by an SMA locking and releasing device (2) arranged in the belly of the machine; The SMA locking and releasing device (2) comprises a cylindrical helical torsion spring (201), a rotary arm (202), a bayonet (203), a first compression spring (204), an SMA wire (205), a second compression spring (206), a bayonet seat (208) and a locking seat (209), wherein the bayonet seat (208) is a cylindrical structure, and a bayonet slot (210) for inserting the bayonet (203) is provided at its right end, and the inner end of the bayonet slot (210) is aligned with the inner end of the bayonet (203). The first compression spring (204) is connected between the two parts, the SMA wire (205) is sleeved on the inner side of the first compression spring (204), the inner end of the SMA wire (205) is connected to the inner end face of the bayonet (203), and the outer end of the SMA wire (205) passes through the inner end of the bayonet slot (210) and is connected to the outside; the locking seat (209) is a square structure arranged below the bayonet seat (208), and the locking bayonet (207) is a cylindrical structure, with its right A limiting portion (211) is formed at the end thereof, and the limiting portion (211) is a cylindrical structure having an outer diameter larger than that of the locking bayonet (207). A limiting groove (212) for sliding of the limiting portion (211) is formed inside the locking seat (209). A bayonet hole (213) for passing the locking bayonet (207) is provided at the left end of the limiting groove (212). The second compression spring (213) is connected between the left end of the limiting portion (211) and the left end of the limiting groove (212). 06); the top of the right end of the locking seat (209) forms an opening (214) communicating with the outside, and the top of the outer end of the limiting portion (211) forms a limiting inclined surface (215); the right end of the swing arm (202) is hinged to the belly of the machine and driven to rotate clockwise by the cylindrical helical torsion spring (201), and the left end of the swing arm (202) forms an upper inclined surface (216) and a lower inclined surface (217), and the upper inclined surface (216) and the lower inclined surface (217) form an isosceles triangle structure.

2. The lightweight UAV landing gear based on the SMA locking and releasing device according to claim 1, characterized in that: The lower inclined surface (217) has the same slope as the limiting inclined surface (215); when the bayonet (203) is extended, the bottom end of the lower inclined surface (217) is in close contact with the bottom end of the limiting inclined surface (215); when the bayonet (203) is retracted, the bottom end of the lower inclined surface (217) is in close contact with the top end of the limiting inclined surface (215).

3. The lightweight UAV landing gear based on the SMA locking and releasing device according to claim 2, characterized in that: A reset slope (219) is formed at the bottom of the left end of the locking latch (207), and the bottom end of the reset slope (219) is inclined toward the lower right.

4. The lightweight UAV landing gear based on the SMA locking and releasing device according to claim 3, characterized in that: The left end of the opening (214) forms an opening inclined surface with the same slope as the limiting inclined surface (215).

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