Unmanned aerial vehicle air-based recovery device and method based on magnetorheological buffering

Abstract

The invention relates to the technical field of unmanned aerial vehicles, and discloses an unmanned aerial vehicle air-based recovery device and method based on magneto-rheological buffering, and the unmanned aerial vehicle air-based recovery device comprises a fixed platform, a recovery hydraulic cylinder, a magneto-rheological universal buffer, an adhesion device, an actuating hydraulic cylinder and a control system; the fixed platform is fixed above the mother machine bottom cabin door, the control system is arranged at the bottom of the fixed platform, a moving unit is arranged at the bottom of the fixed platform, and the connecting ends of the recovery hydraulic cylinder and the actuating hydraulic cylinder are respectively connected to the moving unit; the other end of the actuating hydraulic cylinder is hinged to a cylinder body of the recycling hydraulic cylinder and used for driving the recycling hydraulic cylinder to conduct pitching motion. One end of the magneto-rheological universal buffer is fixed to the driving end of the recovery hydraulic cylinder, and the other end of the magneto-rheological universal buffer is connected to the adhesion device which is used for making contact with the unmanned aerial vehicle; the control system is in control connection with the moving unit, the recovery hydraulic cylinder, the magneto-rheological universal buffer and the actuating hydraulic cylinder. And multi-dimensional omni-directional self-adaptive buffering is achieved, and the complex impact load is remarkably reduced.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) technology, specifically to a UAV airborne recovery device and method based on magnetorheological buffering. Background Technology

[0002] With the rapid development of modern military technology, the combat functions of unmanned aerial vehicles (UAVs) have expanded from traditional auxiliary functions such as tactical reconnaissance, battlefield surveillance, radar guidance, and air defense weapon decoys to active combat missions such as ground / air target attack and interception. Among these, swarm-type UAV combat systems, with their saturation attack capabilities, can effectively penetrate enemy air defense lines, becoming an important piece of equipment in modern warfare. However, small and medium-sized UAVs are limited by their combat radius, making it difficult to fully utilize the advantages of swarm warfare in long-range forward deployment missions. Therefore, the "mother-daughter" solution has emerged—using a long-range, high-payload mother aircraft to transport unmanned aerial vehicles to the mission area, and leveraging air-launch and recovery technologies to achieve long-range deployment and multi-round operations. Airborne UAV recovery technology, as the core of this solution, has become a key technical challenge that urgently needs to be overcome. Currently, airborne recovery methods for small UAVs both domestically and internationally are mainly divided into two categories: rigid recovery and flexible recovery. Rigid recovery technologies mainly include methods such as robotic arm grasping and recovery, aerial hooking and recovery, aerial pallet recovery, and aerial net collision recovery. While these technologies have the advantages of low terminal guidance accuracy requirements and high recovery success rates, they also have significant drawbacks: the overall scheme design is complex, and the development of precise control algorithms is difficult; aerial hooking and recovery is inefficient and highly dependent on the environment; aerial pallet recovery and aerial net collision recovery can easily damage sensitive front-end equipment of the UAV and are prone to propeller entanglement with the net.

[0003] Flexible recovery technology, currently mainly using cable buoy recovery, suffers from high operational difficulty and low recovery efficiency, failing to meet the high-efficiency recovery requirements of "mother-daughter" systems operating in multiple rounds.

[0004] In summary, most existing rigid and flexible recycling solutions are still in the demonstration and design stage and have not yet been put into engineering application. In recent years, telescopic boom recovery mechanisms have attracted widespread attention in the industry due to their low degree of freedom, simple structure, and easy control, becoming an important research direction in UAV airborne recovery technology. However, existing telescopic boom recovery mechanism designs generally suffer from low energy dissipation efficiency, failing to effectively suppress the high-amplitude impact load generated at the moment of docking between the UAV and the recovery boom. This results in the UAV and recovery boom experiencing significant overloads, severely affecting the stability and reliability of the recovery process and limiting its practical application in "mother-daughter" systems. Therefore, developing a telescopic boom drone recovery mechanism that can effectively dissipate collision energy is key to solving the lack of stability and reliability in the airborne recovery of telescopic boom drones. It is of great significance for promoting the engineering implementation of the "mother-daughter drone" system and improving the long-range swarm combat capability of small and medium-sized drones. Summary of the Invention

[0005] In order to overcome the shortcomings of the existing technology, the present invention aims to provide a UAV airborne recovery device and method based on magnetorheological buffering, so as to solve the technical problems of how to achieve accurate and efficient UAV airborne recovery, improve docking stability and safety, and reduce the possible damage to the recovery device and UAV caused by docking collision.

[0006] This invention is achieved through the following technical solution: One technical solution of the present invention is a UAV airborne recovery device based on magnetorheological buffer, comprising a fixed platform, a recovery hydraulic cylinder, a magnetorheological universal buffer, an adhesion device, an actuating hydraulic cylinder, and a control system. The fixed platform is fixed above the bottom hatch of the mother machine, and the control system is set at the bottom of the fixed platform. The bottom of the fixed platform is equipped with a moving unit, and the connection ends of the recovery hydraulic cylinder and the actuation hydraulic cylinder are respectively connected to the moving unit. The other end of the actuating hydraulic cylinder is hinged to the cylinder body of the recovery hydraulic cylinder, and is used to drive the recovery hydraulic cylinder to perform pitching motion; One end of the magnetorheological universal buffer is fixed to the drive end of the recovery hydraulic cylinder, and the other end is connected to the adhesion device, which is used to contact the drone. The control system is connected to the moving unit, the recovery hydraulic cylinder, the magnetorheological universal buffer, and the actuation hydraulic cylinder.

[0007] Preferably, the moving unit includes two sets of moving components spaced apart, and the connecting ends of the recovery hydraulic cylinder and the actuation hydraulic cylinder are respectively connected to the two sets of moving components; The moving components include a guide rail, a slider, and a lead screw mounted on the bottom of the fixed platform; The slider is threaded onto the lead screw and moves along the guide rail via the lead screw; the slider has a connecting end for hinged retraction or actuation of the hydraulic cylinder, and the control end of the lead screw is connected to the control system.

[0008] Preferably, the magnetorheological universal damper includes a linear magnetorheological damper and a spherical magnetorheological damper; The connection end of the linear magnetorheological buffer is connected to the drive end of the recovery hydraulic cylinder; The other end of the linear magnetorheological damper is connected to the adhesion device via a spherical magnetorheological damper; The control terminals of the linear magnetorheological buffer and the spherical magnetorheological buffer are respectively connected to the control system.

[0009] Preferably, the linear magnetorheological damper includes a cylinder, a piston, and a piston rod; One end of the cylinder is connected to the drive end of the recovery hydraulic cylinder, and the other end is positioned towards the spherical magnetorheological buffer; the piston is slidably disposed inside the cylinder, wherein a first return spring is disposed between one end of the piston and the inner opposite surface of the cylinder; the other end of the piston and the inner opposite surface of the cylinder are filled with a first magnetorheological fluid; wherein the control system is connected to the piston control. A damping channel for the flow of the first magnetorheological fluid is provided between the side wall of the piston and the inner wall of the cylinder. One end of the piston rod is fixed inside the piston, and the other end is connected to the adhesion device after passing through the piston, cylinder and spherical magnetorheological damper in sequence.

[0010] Preferably, the piston includes a piston shell, a first magnetic core, and a first excitation coil; The first magnetic core is disposed inside the piston housing, and the first excitation coil is wound on the first magnetic core. The control terminal of the control system is connected to the first excitation coil. One end of the piston rod passes through the first magnetic core inside the piston housing, and the other end connects to the adhesion device after passing through the piston housing, cylinder, and spherical magnetorheological buffer in sequence.

[0011] Preferably, the spherical magnetorheological damper includes a damper housing, a core housing, a fixing ring, and several oil scraping rings; The buffer housing is sleeved on the spherical core housing with the same center, and a limiting boss is provided between the upper and lower ends of the buffer housing and the spherical core housing to limit the translation of the spherical core housing; a fixed ring is fixed around the spherical core housing, and several oil scraping rings are connected to the fixed ring at both ends and are slidably arranged along the circumferential surface of the spherical core housing. A second return spring is provided between adjacent oil scraping rings and fixed rings, and a second magnetorheological fluid is filled between the buffer housing and the spherical core housing; the control system is controlled and connected to the spherical core housing. The piston rod is connected to the adhesion device after passing through the buffer housing and the ball core housing; The fixed ring includes two identical semicircular rings, which are fixedly connected by a retaining ring. After the retaining rings are engaged, they form a cylindrical pin hole. The semicircular rings are symmetrically provided with several damping holes in the thickness direction for the flow of the second magnetorheological fluid. The oil scraper ring includes four semicircular rings, one end of which is provided with a cylindrical pin. The four semicircular rings are inserted into the cylindrical pin holes through the cylindrical pins. The oil scraper ring is equipped with a spring seat for fixing the second return spring.

[0012] Preferably, the buffer housing includes an upper buffer housing and a lower buffer housing that are snapped together, with the spherical core housing located between the upper buffer housing and the lower buffer housing; the upper buffer housing and the lower buffer housing are respectively provided with through holes for inserting the piston rod.

[0013] Preferably, the core shell includes an upper core shell and a lower core shell that are snapped together, a second magnetic core is disposed between the upper core shell and the lower core shell, and a second excitation coil is wound on the second magnetic core, wherein the control terminal of the control system is controlled and connected to the second excitation coil; the upper core shell and the lower core shell are respectively provided with connecting holes for inserting the piston rod; A spring groove is provided between the upper and lower shells of the sphere core and the upper and lower shells of the buffer, relative to the position of the second return spring, and the second return spring reciprocates within the spring groove.

[0014] Preferably, the control system includes a drive module and a sensor module; The drive module includes a current drive module and a hydraulic drive module; the current drive module is connected to the control terminals of the lead screw, the first excitation coil and the second excitation coil respectively; the hydraulic drive module is connected to the control terminals of the recovery hydraulic cylinder and the actuation hydraulic cylinder respectively. The sensor module includes a binocular vision optical measurement device and an accelerometer, wherein the binocular vision optical measurement device is used to identify the characteristics of the UAV model, speed, and attitude.

[0015] Another technical solution of the present invention is a method for airborne recovery of unmanned aerial vehicles (UAVs) based on magnetorheological buffering, which, based on the aforementioned UAV airborne recovery device, includes the following process: During the docking preparation phase, the control system autonomously identifies the characteristics of the UAV model, speed, and attitude. Based on the identified characteristics, it drives the moving unit to adjust the relative positions of the recovery hydraulic cylinder and the actuation hydraulic cylinder on the fixed platform, and drives the actuation hydraulic cylinder to adjust the pitch and extension length of the recovery hydraulic cylinder. At the same time, it adjusts the current in the magnetorheological universal buffer based on the identified characteristics to control the viscosity of the magnetorheological fluid, so that the magnetorheological universal buffer reaches the optimal docking state. During the docking process, the UAV approaches the adhesive device at a certain relative speed and impacts the adhesive device and the magnetorheological universal buffer along the axis. The magnetorheological universal buffer dissipates the impact energy received, preparing for the next impact. During the recovery phase, the magnetorheological universal damper dampens the vibration of the drone, ensuring the stability of the drone during the recovery phase. Then, the control system drives the recovery hydraulic cylinder to retract, so that the drone is recovered into the bottom compartment of the mother machine. After recovery, the magnetorheological universal buffer is de-energized and reset to prepare for a docking buffering task. Compared with the prior art, the present invention has the following beneficial technical effects: This invention provides an airborne recovery device for unmanned aerial vehicles (UAVs) based on magnetorheological buffering. It constructs an overall architecture comprising a fixed platform, a recovery hydraulic cylinder, a magnetorheological universal buffer, an adhesion device, an actuating hydraulic cylinder, and a control system. The position adjustment of the recovery and actuating hydraulic cylinders is achieved via a mobile unit, and the pitch movement of the recovery hydraulic cylinder is driven by the actuating hydraulic cylinder. Combined with the connection design of the magnetorheological universal buffer and the adhesion device, and the centralized control of the control system, this provides a basic structural support for multi-dimensional omnidirectional adaptive buffering. It can initially achieve coordinated dissipation of axial and non-axial impact loads. Simultaneously, by adjusting the position and pitch angle to adapt to the UAV docking attitude, the requirement for absolute coaxiality is reduced, improving docking fault tolerance. Furthermore, the overall control of each component by the control system can initially suppress vibration after docking, ensuring recovery stability. This lays the foundation for achieving the overall effect of reducing complex impact loads, improving docking fault tolerance, and enhancing recovery stability.

[0016] Furthermore, the moving unit consists of two sets of moving components including guide rails, sliders, and lead screws. The recovery hydraulic cylinder and the actuation hydraulic cylinder are respectively connected to the two sets of sliders. The sliders are driven by the lead screws to move along the guide rails, and the control system controls the movement of the lead screws. This allows for precise adjustment of the relative positions of the recovery hydraulic cylinders and the actuation hydraulic cylinders, enabling the device to perform targeted positional adaptation based on the location characteristics of the UAV. This effectively compensates for positional deviations, significantly reduces the requirement for absolute coaxiality between the UAV and the recovery mechanism, and significantly improves the docking fault tolerance rate.

[0017] Furthermore, the magnetorheological universal buffer is divided into linear and spherical magnetorheological buffers. The linear magnetorheological buffer is connected to the drive end of the recovery hydraulic cylinder, and the spherical magnetorheological buffer is connected to the adhesion device. Both are controlled by the control system, realizing the division of labor and cooperation between axial and non-axial buffering: the linear magnetorheological buffer can precisely dissipate the initial impact load along the extension and retraction direction of the rod, while the spherical magnetorheological buffer can effectively absorb and suppress non-axial impacts and vibrations such as tilt, yaw, and pitch generated at the moment of docking, forming a multi-dimensional omnidirectional adaptive buffering system, which significantly reduces the impact of complex impact loads on the device.

[0018] Furthermore, by designing the cylinder, piston, piston rod, first return spring, first magnetorheological fluid, and damping channel of the linear magnetorheological buffer, the first magnetorheological fluid can flow through the damping channel when the piston slides in the cylinder. Combined with the elastic effect of the first return spring, precise and controllable axial buffering is achieved. The control system can adjust the piston movement to change the flow state of the magnetorheological fluid according to the docking speed and the UAV model, thereby adaptively adjusting the axial damping force to ensure optimal axial damping effect, effectively dissipating the initial axial impact load and preventing peak overload from causing hydraulic telescopic rod failure. The first return spring not only assists the piston in returning to its original position and preparing for the next impact buffer, but also helps to attenuate axial vibration after docking. Combined with the damping effect of the magnetorheological fluid, it improves the stability of the recovery process.

[0019] Furthermore, by setting a first magnetic core and a first excitation coil wound around the magnetic core inside the piston, and connecting the control system to the first excitation coil, precise control of the electrical signal of the axial damping force is achieved: the control system can adjust the current input to the first excitation coil and change the magnetic field strength according to the characteristics of the UAV model and docking speed identified by the binocular vision optical measurement equipment, thereby adjusting the viscosity of the first magnetorheological fluid in real time, so that the axial damping force of the linear magnetorheological buffer can dynamically adapt to the impact load under different working conditions, achieve the optimal axial buffering effect, maximize the dissipation of axial impact energy, and avoid the failure of the hydraulic telescopic rod due to peak overload.

[0020] Furthermore, by designing a spherical magnetorheological buffer consisting of a buffer housing, a core housing, a fixed ring, an oil scraper ring, a second return spring, and a second magnetorheological fluid, the damping hole of the fixed ring allows the flow of the second magnetorheological fluid. Through the cooperation between the oil scraper ring and the fixed ring, and the elastic action of the second return spring, the core housing can rotate in multiple directions relative to the buffer housing, effectively absorbing non-axial impacts such as tilt, yaw, and pitch generated during UAV docking, significantly reducing the impact of complex impact loads on the recovery mechanism. The fixed ring adopts a structure of two semi-circular rings fixed by a snap ring, and the oil scraper ring cooperates with the cylindrical pin hole of the fixed ring through a cylindrical pin, making the assembly and maintenance of the spherical buffer more convenient, while ensuring the flexibility of the core housing's movement. This allows the end of the telescopic rod to adaptively conform to the UAV docking surface within a certain angle range, and even with positional and angular deviations, docking can be successfully completed and guided to a coaxial position, significantly reducing the docking accuracy threshold and improving the docking fault tolerance rate.

[0021] Furthermore, by designing the buffer housing as an upper and lower shell that interlock, and providing through holes for the piston rod to pass through, the structural integrity and ease of assembly of the spherical magnetorheological buffer are ensured, as well as the smooth connection between the piston rod and the adhesion device. This allows the piston rod to flexibly adjust its angle as the spherical shell rotates in multiple directions without affecting the absorption and buffering effect of non-axial impacts. The interlocking shell structure facilitates the installation and maintenance of internal components, while also improving the sealing performance of the buffer housing, reducing leakage of the second magnetorheological fluid, ensuring the stability of damping force adjustment, and thus ensuring the structural reliability of the spherical magnetorheological buffer when absorbing non-axial impacts and adapting to angular deviations.

[0022] Furthermore, by designing the spherical core shell as a relatively interlocking upper and lower shell, housing a second magnetic core and a second excitation coil, and connecting the control system to the second excitation coil, precise control of non-axial damping force is achieved. The control system can adjust the current input to the second excitation coil according to the attitude characteristics and vibration of the UAV, changing the magnetic field strength, and thus adjusting the viscosity of the second magnetorheological fluid. This allows the spherical magnetorheological buffer to adaptively absorb non-axial impacts of different intensities, precisely suppressing vibrations in the tilt, yaw, and other directions. The spring groove provides a stable installation and movement space for the second return spring, ensuring smooth reciprocating motion of the return spring, assisting the spherical core shell in resetting, and improving stability after docking. The interlocking structure of the spherical core shell facilitates the installation and maintenance of the internal magnetic core and coil, while ensuring the concentration of the magnetic field and improving the response speed and accuracy of the magnetorheological fluid viscosity adjustment.

[0023] Furthermore, by splitting the control system into a drive module and a sensor module, the drive module includes current drive and hydraulic drive, which control the lead screw, excitation coil, and hydraulic cylinder respectively. The sensor module includes a binocular vision optical measurement device and an accelerometer. The binocular vision device can accurately identify the UAV model, speed, and attitude characteristics, providing precise data support for the adjustment of each component. This makes the position adjustment of the moving unit, the pitch adjustment of the actuating hydraulic cylinder, and the damping force adjustment of the magnetorheological buffer more targeted, achieving the optimal docking state. Then, based on the docking speed and UAV model, the viscosity of the magnetorheological fluid is adaptively adjusted to ensure optimal damping force, effectively dissipating impact loads, while reducing docking accuracy requirements and improving fault tolerance. The accelerometer can monitor the vibration of the UAV and the device in real time, providing vibration feedback to the control system. This allows the current drive and hydraulic drive modules to apply controllable damping force in a timely manner to suppress vibration and improve recovery stability. The division of labor and cooperation between the current drive and hydraulic drive ensures the synergy between mechanical action and damping adjustment, making the control of the entire recovery process more precise and the response faster. This comprehensively guarantees the realization of multi-dimensional buffering, high fault tolerance, and high stability, improving the automation and intelligence level of the device.

[0024] This invention also provides a method for airborne recovery of unmanned aerial vehicles (UAVs) based on magnetorheological buffering. During the docking preparation phase, the control system identifies UAV characteristics and adjusts the position, pitch, extension length, and magnetorheological fluid viscosity accordingly, enabling the device to enter the optimal docking state in advance. This ensures that the linear and spherical magnetorheological buffers can accurately adapt to impact loads, effectively reducing complex impacts. Simultaneously, through adaptive adjustment of attitude and position, the docking accuracy threshold is significantly lowered, and the fault tolerance rate is improved. During docking, the magnetorheological universal buffer efficiently dissipates impact energy through axial and non-axial synergistic buffering, preventing component damage. During the recovery phase, the damping adjustment of the magnetorheological buffer attenuates vibrations, ensuring UAV stability and providing a guarantee for smooth recovery. After recovery, the buffer is powered off and reset, ensuring the device can be reused. This improves the automation and reliability of the recovery process and reduces the stringent requirements on the flight control system. Attached Figure Description

[0025] Figure 1 This is an overall schematic diagram of the UAV airborne recovery device based on magnetorheological buffer in an embodiment of the present invention; Figure 2 This is a cross-sectional view of the linear magnetorheological buffer structure in an embodiment of the present invention; Figure 3 This is a cross-sectional view of the spherical magnetorheological damper in an embodiment of the present invention; Figure 4 This is a schematic diagram of the damper sphere structure in an embodiment of the present invention; Figure 5 This is a schematic diagram of the semi-circular ring of the fixing ring in an embodiment of the present invention; Figure 6 This is a schematic diagram of the semi-circular ring of the oil scraper ring in an embodiment of the present invention; Figure 7 This is a schematic diagram of the control system in an embodiment of the present invention; In the diagram: 1. Fixed platform; 2. Slider; 3. Lead screw; 4. Retraction hydraulic cylinder; 5. Magnetorheological universal damper; 6. Adhesion device; 7. Actuating hydraulic cylinder; 8. Control system; 51. Linear magnetorheological buffer; 52. Spherical magnetorheological buffer; 511. Cylinder; 512. First return spring; 513. Piston; 514. Damping channel; 515. Piston rod; 516. First magnetorheological fluid; 5131. Piston housing; 5132. First magnetic core; 5133. First excitation coil; 521. Buffer housing; 522. Core housing; 523. Fixing ring; 524. Oil scraper ring; 525. Second return spring; 526. Second magnetorheological fluid; 527. Limiting boss; 5211. Upper housing of the buffer; 5212. Lower housing of the buffer; 5213. Through hole; 5221. Upper shell of the spherical core; 5222. Second magnetic core; 5223. Second excitation coil; 5224. Lower shell of the spherical core; 5225. Spring groove; 5226. Connecting hole; 5231, Damping hole; 5232, Snap ring; 5233, Cylindrical pin hole; 5241, Spring seat; 5242, Cylindrical pin; 81. Drive module; 82. Sensor module; 811. Current-driven module; 821. Hydraulic-driven module; 821. Binocular vision optical measurement equipment; 822. Accelerometer sensor. Detailed Implementation

[0026] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0027] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0028] The purpose of this invention is to provide a UAV airborne recovery device and method based on magnetorheological buffering, in order to solve the technical problems of how to achieve accurate and efficient UAV airborne recovery, improve docking stability and safety, and reduce the possible damage to the recovery device and UAV caused by docking collisions.

[0029] The present invention will now be described in further detail with reference to the accompanying drawings: Example 1 See Figure 1In one embodiment of the present invention, a UAV airborne recovery device based on magnetorheological buffer is provided, including a fixed platform 1, a recovery hydraulic cylinder 4, a magnetorheological universal buffer 5, an adhesion device 6, an actuating hydraulic cylinder 7, and a control system 8. The fixed platform 1 is fixed above the bottom door of the mother machine, and the control system 8 is located at the bottom of the fixed platform 1. A moving unit is provided at the bottom of the fixed platform 1, and the connecting ends of the recovery hydraulic cylinder 4 and the actuating hydraulic cylinder 7 are respectively connected to the moving unit. The other end of the actuating hydraulic cylinder 7 is hinged to the cylinder body of the recovery hydraulic cylinder 4 and is used to drive the recovery hydraulic cylinder 4 to perform pitch movement. One end of the magnetorheological universal buffer 5 is fixed to the driving end of the recovery hydraulic cylinder 4, and the other end is connected to the adhesion device 6, which is used to contact the UAV. The control system 8 is connected to the moving unit, the recovery hydraulic cylinder 4, the magnetorheological universal buffer 5, and the actuating hydraulic cylinder 7.

[0030] In this embodiment, the recovery hydraulic cylinder 4 is driven by a double-acting two-stage hydraulic cylinder, and the actuation hydraulic cylinder 7 is driven by a double-acting hydraulic cylinder.

[0031] Specifically, the moving unit includes two sets of spaced-apart moving components. The connecting ends of the recovery hydraulic cylinder 4 and the actuation hydraulic cylinder 7 are respectively connected to the two sets of moving components. The moving components include a guide rail, a slider 2, and a lead screw 3 set at the bottom of the fixed platform 1. The slider 2 is threaded onto the lead screw 3 and moves along the guide rail through the lead screw 3. The connecting end of the slider 2 is used to hinge the recovery hydraulic cylinder 4 or the actuation hydraulic cylinder 7. The control end of the lead screw 3 is connected to the control system 8.

[0032] Specifically, the magnetorheological universal buffer 5 includes a linear magnetorheological buffer 51 and a spherical magnetorheological buffer 52; the connecting end of the linear magnetorheological buffer 51 is connected to the driving end of the recovery hydraulic cylinder 4; the other end of the linear magnetorheological buffer 51 is connected to the adhesion device 6 through the spherical magnetorheological buffer 52; the control ends of the linear magnetorheological buffer 51 and the spherical magnetorheological buffer 52 are respectively connected to the control system 8.

[0033] Among them, according to Figure 2As shown, the linear magnetorheological buffer 51 includes a cylinder 511, a piston 513, and a piston rod 515. One end of the cylinder 511 is connected to the drive end of the recovery hydraulic cylinder 4, and the other end is positioned towards the spherical magnetorheological buffer 52. The piston 513 is slidably disposed inside the cylinder 511, wherein a first return spring 512 is disposed between one end of the piston 513 and the inner opposite surface of the cylinder 511. The other end of the piston 513 and the inner opposite surface of the cylinder 511 are filled with a first magnetorheological fluid 516. The control system 8 is connected to the piston 513. A damping channel 514 for the flow of the first magnetorheological fluid 516 is opened between the side wall of the piston 513 and the inner wall of the cylinder 511. One end of the piston rod 515 is fixed inside the piston 513, and the other end passes through the piston 513, the cylinder 511, and the spherical magnetorheological buffer 52 in sequence before being connected to the adhesion device 6.

[0034] In this embodiment, the lower end of the actuating hydraulic cylinder 7 is hinged to the first-stage hydraulic cylinder of the recovery hydraulic cylinder 4, and the cylinder 511 directly serves as the third-stage cylinder of the recovery hydraulic cylinder 4.

[0035] The piston 513 includes a piston shell 5131, a first magnetic core 5132, and a first excitation coil 5133. The first magnetic core 5132 is disposed inside the piston shell 5131, and the first excitation coil 5133 is wound on the first magnetic core 5132. The control terminal of the control system 8 is connected to the first excitation coil 5133. One end of the piston rod 515 passes through the first magnetic core 5132 inside the piston shell 5131, and the other end is connected to the adhesion device 6 after passing through the piston shell 5131, cylinder 511, and spherical magnetorheological buffer 52 in sequence.

[0036] In this embodiment, the first magnetic core 5132 is made of a soft magnetic material with low coercivity. The piston outer shell diameter is slightly smaller than the cylinder inner diameter, and a damping channel and damping hole are left between the piston and the cylinder for the magnetorheological fluid to flow. The first excitation coil is wound in the annular groove in the middle of the first magnetic core. The first return spring is installed between the upper part of the cylinder and the top of the piston. When the first return spring is at its original length, the piston is located at the bottom of the cylinder.

[0037] Among them, according to Figure 3 and Figure 4As shown, the spherical magnetorheological damper 52 includes a damper housing 521, a core housing 522, a fixing ring 523, and several oil scraping rings 524. The damper housing 521 is sleeved on the core housing 522 with the same center, and a limiting boss 527 is provided between the upper and lower ends of the damper housing 521 and the core housing 522 to limit the translation of the core housing 522. The fixing ring 523 is fixed around the core housing 522. The two ends of the several oil scraping rings 524 are respectively connected to the fixing ring 523 and are slidably arranged along the circumferential surface of the core housing 522. A second return spring 525 is provided between adjacent oil scraping rings 524 and fixing rings 523. A second magnetorheological fluid 526 is filled between the damper housing 521 and the core housing 522. The control system 8 is controlled and connected to the core housing 522. The piston rod 515 is connected to the adhesion device 6 after passing through the damper housing 521 and the core housing 522. Figure 5 As shown, the fixed ring 523 includes two identical semicircular rings, which are fixedly connected by a retaining ring 5232. The retaining rings 5232, when engaged, form a cylindrical pin hole 5231. Several damping holes 5231 are symmetrically provided in the thickness direction of the semicircular rings for the flow of the second magnetorheological fluid 526. According to... Figure 6 As shown, the oil scraper ring 524 includes four semicircular rings, one end of which is provided with a cylindrical pin 5242. The four semicircular rings are inserted into the cylindrical pin holes 5231 through cylindrical pins. The oil scraper ring 524 is provided with a spring seat 5241 for fixing the second return spring 525.

[0038] In this embodiment, a limiting boss is provided between the buffer housing 521 and the core housing 522 to limit the translation of the core housing 522; both the inner and outer sides of the oil scraper ring 524 are provided with sealing strips to prevent liquid leakage; a spring seat 5241 for axially fixing the second return spring 525 is provided on the oil scraper ring 524, which cooperates with the spring groove to fix and reset the second return spring 525. After the recovery task is completed and the power is cut off, the oil scraper ring 524 returns to the state of abutting the symmetrical boss under the action of the spring force, preparing for the next docking buffer.

[0039] The buffer housing 521 includes an upper buffer housing 5211 and a lower buffer housing 5212 that are fastened together. The spherical core housing 522 is located between the upper buffer housing 5211 and the lower buffer housing 5212. The upper buffer housing 5211 and the lower buffer housing 5212 are respectively provided with through holes 5213 for inserting the piston rod 515.

[0040] The core housing 522 includes an upper core housing 5221 and a lower core housing 5224 that are fastened together. A second magnetic core 5222 is disposed between the upper core housing 5221 and the lower core housing 5224, and a second excitation coil 5223 is wound on the second magnetic core 5222. The control terminal of the control system 8 is connected to the second excitation coil 5223. The upper core housing 5221 and the lower core housing 5224 are respectively provided with connecting holes 5226 for inserting the piston rod 515. A spring groove 5225 is provided between the upper core housing 5221 and the lower core housing 5224 and the upper buffer housing 5211 and the lower buffer housing 5212 at a position relative to the second return spring 525. The second return spring 525 reciprocates within the spring groove 5225.

[0041] Among them, according to Figure 7 As shown, the control system 8 includes a drive module 81 and a sensor module 82; the drive module 81 includes a current drive module 811 and a hydraulic drive module 821; the current drive module 811 is connected to the control terminals of the lead screw 3, the first excitation coil 5133 and the second excitation coil 5223 respectively; the hydraulic drive module 821 is connected to the control terminals of the recovery hydraulic cylinder 4 and the actuation hydraulic cylinder 7 respectively; the sensor module 82 includes a binocular vision optical measurement device 821 and an acceleration sensor 822, wherein the binocular vision optical measurement device 821 is used to identify the characteristics of the UAV model, speed and attitude.

[0042] In this embodiment, the upper end of the buffer shell has a circular hole, and its lower end is directly fixed to the adhesive device 6. The inner surfaces of the upper and lower shells are symmetrically distributed with annular spring grooves. The upper opening and lower end of the spherical shell have limiting bosses. The top of the bosses is in close contact with the spherical shell, restricting the translation of the spherical shell. The core shell consists of an upper core shell and a lower core shell, a second magnetic core, and a second excitation coil wound around an annular groove in the middle of the second magnetic core. The core shell has an annular groove on its side, and spring grooves are symmetrically opened in the upper and lower halves of the core shell. A threaded hole is provided at the top of the upper half of the core shell, and the core is directly threaded to the piston rod of the linear magnetorheological buffer through a circular hole on the buffer shell.

[0043] The fixing ring is composed of two semi-circular rings. A radial cylindrical groove is opened on its side for connecting the oil scraper ring. Eight through damping holes are symmetrically distributed in the thickness direction of the fixing ring. An annular spring seat for axially fixing the second return spring is opened in the middle of the oil scraper ring. The fixing ring is embedded in the annular groove on the ball core shell. A cylindrical pin is provided at one end of the oil scraper ring for inserting into the radial groove on the side of the fixing ring. The outer sides of the fixing ring and the oil scraper ring protrude from the outside of the ball core, and sealing rings are installed on the inner and outer sides to tightly fit the inner surface of the ball core shell and the buffer shell. The second return spring is installed on the spring groove and the spring seat.

[0044] Example 2 This embodiment also provides a method for UAV airborne recovery based on magnetorheological buffering, which, based on the aforementioned UAV airborne recovery device based on magnetorheological buffering, includes the following process: During the docking preparation phase, the binocular vision optical measurement equipment in the control system autonomously identifies the UAV's model, speed, attitude, and other characteristics. An electrically driven lead screw rotates to adjust the slider position, while hydraulically driven actuation cylinders and recovery cylinders adjust the pitch and extension length of the recovery rod. Simultaneously, based on the UAV's speed and attitude characteristics, the control system intelligently adjusts the current in the first and second excitation coils to control the viscosity of the magnetorheological fluid, achieving optimal docking conditions for the magnetorheological universal buffer.

[0045] During docking, the UAV contacts the adhesion device at a certain relative speed. The axial impact is transmitted along the adhesion device, the spherical magnetorheological damper, and then to the linear magnetorheological damper. The piston moves upward, squeezing the high-viscosity magnetorheological fluid through the damping channel and damping orifice, dissipating most of the impact energy along the recovery rod direction. Subsequently, the piston returns to the bottom of the cylinder under the action of the return spring, preparing for the next impact. Because the UAV docking has a relative velocity component perpendicular to the recovery rod direction, the adhesion device drives the damper housing to rotate relative to the spherical core housing. The upper and lower limit bosses rotate relative to the spherical core and drive the oil scraper ring to squeeze the high-viscosity magnetorheological fluid through the damping orifice to dissipate the lateral impact energy.

[0046] During the recovery phase, the UAV is prone to continuous shaking or even resonance due to unstable airflow and the wake of the mother aircraft. The spherical magnetorheological damper shell rotates relative to the core and dampens the UAV's vibration, ensuring the stability of the UAV during recovery. Subsequently, the recovery hydraulic cylinder and the actuation hydraulic cylinder contract hydraulically, and the UAV is recovered into the mother aircraft's cabin.

[0047] After the recovery is completed, the magnetorheological universal buffer device is de-energized, and the reset spring pushes the linear magnetorheological buffer piston and the spherical magnetorheological buffer oil scraper ring back to their initial positions, preparing for the next docking buffering task.

[0048] In summary, the present invention provides a UAV airborne recovery device and method based on magnetorheological buffering, achieving multi-dimensional omnidirectional adaptive buffering and significantly reducing complex impact loads. Specifically, the linear magnetorheological buffer dissipates the initial impact load along the extension direction of the rod. The binocular vision optical monitoring device can adaptively adjust the output current according to the docking speed and UAV model to ensure that the linear magnetorheological buffer provides optimal axial damping force, preventing peak overload from causing hydraulic telescopic rod failure. The spherical magnetorheological damper effectively absorbs and suppresses non-axial impacts and vibrations such as roll, yaw, and pitch generated by the UAV at the moment of docking. This is crucial for offsetting eccentric impacts caused by airflow disturbances and mismatches in UAV attitude fine-tuning, effectively preventing bending deformation and breakage of the recovery rod. The omnidirectional buffer structure allows the end of the telescopic rod to adaptively "fit" and "capture" the UAV docking surface within a certain angle and range. Even with certain positional and angular deviations, docking can be successfully completed and the UAV smoothly guided to a coaxial position, thereby significantly reducing the docking accuracy threshold and the stringent requirements on the flight control system, greatly improving the docking fault tolerance. The spherical buffer effectively suppresses vibration after docking, improving the smoothness of the recovery process. After docking, the UAV and telescopic boom may experience continuous swaying or even resonance due to turbulence and the wake of the mother aircraft, significantly reducing the service life of the telescopic boom. The omnidirectional magnetorheological buffer in this invention can act as an active dynamic stabilizer, applying controllable damping forces to the minute oscillations in various directions through the control system, enabling the UAV to stabilize quickly, which creates favorable conditions for subsequent smooth retraction.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A UAV airborne recovery device based on magnetorheological buffering, characterized in that, It includes a fixed platform (1), a recovery hydraulic cylinder (4), a magnetorheological universal buffer (5), an adhesion device (6), an actuating hydraulic cylinder (7), and a control system (8); The fixed platform (1) is fixed above the bottom door of the mother machine, and the control system (8) is set at the bottom of the fixed platform (1). The bottom of the fixed platform (1) is provided with a moving unit, and the connection ends of the recovery hydraulic cylinder (4) and the actuation hydraulic cylinder (7) are respectively connected to the moving unit. The other end of the actuating hydraulic cylinder (7) is hinged to the cylinder body of the recovery hydraulic cylinder (4) to drive the recovery hydraulic cylinder (4) to perform pitching motion; One end of the magnetorheological universal buffer (5) is fixed to the drive end of the recovery hydraulic cylinder (4), and the other end is connected to the adhesive device (6), which is used to contact the UAV. The control system (8) is connected to the moving unit, the recovery hydraulic cylinder (4), the magnetorheological universal buffer (5), and the actuation hydraulic cylinder (7) respectively.

2. The UAV airborne recovery device based on magnetorheological buffering according to claim 1, characterized in that, The moving unit includes two sets of moving components spaced apart, and the connecting ends of the recovery hydraulic cylinder (4) and the actuation hydraulic cylinder (7) are respectively connected to the two sets of moving components; The moving component includes a bottom guide rail, a slider (2), and a lead screw (3) set on the fixed platform (1); The slider (2) is threaded onto the lead screw (3) and moves along the slider (2) within the guide rail via the lead screw (3); the slider (2) is used to hinge the connection end of the recovery hydraulic cylinder (4) or the actuation hydraulic cylinder (7), and the control end of the lead screw (3) is connected to the control system (8).

3. The UAV airborne recovery device based on magnetorheological buffering according to claim 1, characterized in that, The magnetorheological universal buffer (5) includes a linear magnetorheological buffer (51) and a spherical magnetorheological buffer (52). The connection end of the linear magnetorheological buffer (51) is connected to the drive end of the recovery hydraulic cylinder (4); The other end of the linear magnetorheological buffer (51) is connected to the adhesive device (6) via a spherical magnetorheological buffer (52); The control terminals of the linear magnetorheological buffer (51) and the spherical magnetorheological buffer (52) are respectively connected to the control system (8).

4. The UAV airborne recovery device based on magnetorheological buffering according to claim 3, characterized in that, The linear magnetorheological damper (51) includes a cylinder (511), a piston (513), and a piston rod (515). One end of the cylinder (511) is connected to the drive end of the recovery hydraulic cylinder (4), and the other end is set towards the spherical magnetorheological buffer (52); the piston (513) is slidably disposed inside the cylinder (511), wherein a first return spring (512) is provided between one end of the piston (513) and the inner opposite surface of the cylinder (511); the other end of the piston (513) and the inner opposite surface of the cylinder (511) are filled with a first magnetorheological fluid (516); wherein the control system (8) is controlled and connected to the piston (513); A damping channel (514) for the flow of the first magnetorheological fluid (516) is provided between the side wall of the piston (513) and the inner wall of the cylinder (511). One end of the piston rod (515) is fixed inside the piston (513), and the other end is connected to the adhesive device (6) after passing through the piston (513), cylinder (511) and spherical magnetorheological buffer (52) in sequence.

5. The UAV airborne recovery device based on magnetorheological buffering according to claim 4, characterized in that, The piston (513) includes a piston housing (5131), a first magnetic core (5132), and a first excitation coil (5133). The first magnetic core (5132) is disposed inside the piston housing (5131), and the first excitation coil (5133) is wound on the first magnetic core (5132). The control terminal of the control system (8) is connected to the first excitation coil (5133). One end of the piston rod (515) passes through the first magnetic core (5132) inside the piston housing (5131), and the other end is connected to the adhesion device (6) after passing through the piston housing (5131), cylinder (511) and spherical magnetorheological buffer (52) in sequence.

6. The UAV airborne recovery device based on magnetorheological buffering according to claim 5, characterized in that, The spherical magnetorheological damper (52) includes a damper housing (521), a spherical core housing (522), a retaining ring (523), and several oil scraper rings (524). The buffer housing (521) is sleeved on the spherical core housing (522) with the same center, and a limiting boss (527) is provided between the upper and lower ends of the buffer housing (521) and the spherical core housing (522) to limit the translation of the spherical core housing (522); wherein the fixing ring (523) is fixed around the spherical core housing (522), and the two ends of several oil scraping rings (524) are respectively connected to the fixing ring (523) and are slidably arranged along the circumferential surface of the spherical core housing (522). A second return spring (525) is provided between adjacent oil scraping rings (524) and fixing rings (523), and a second magnetorheological fluid (526) is filled between the buffer housing (521) and the spherical core housing (522); wherein the control system (8) is controlled and connected to the spherical core housing (522); The piston rod (515) is connected to the adhesive device (6) after passing through the buffer housing (521) and the core housing (522); The fixed ring (523) includes two identical semicircular rings, which are fixedly connected by a retaining ring (5232). After the retaining ring (5232) is engaged, a cylindrical pin hole (5231) is formed. Several damping holes (5231) are symmetrically provided in the thickness direction of the semicircular rings for the flow of the second magnetorheological fluid (526). The oil scraper ring (524) includes four semicircular rings, one end of which is provided with a cylindrical pin (5242). The four semicircular rings are inserted into the cylindrical pin holes (5231) through cylindrical pins. The oil scraper ring (524) is provided with a spring seat (5241) for fixing the second return spring (525).

7. The UAV airborne recovery device based on magnetorheological buffering according to claim 6, characterized in that, The buffer housing (521) includes an upper buffer housing (5211) and a lower buffer housing (5212) that are fastened together. The spherical core housing (522) is located between the upper buffer housing (5211) and the lower buffer housing (5212). The upper buffer housing (5211) and the lower buffer housing (5212) are respectively provided with through holes (5213) for inserting the piston rod (515).

8. The UAV airborne recovery device based on magnetorheological buffering according to claim 7, characterized in that, The core housing (522) includes an upper core housing (5221) and a lower core housing (5224) that are fastened together. A second magnetic core (5222) is disposed between the upper core housing (5221) and the lower core housing (5224), and a second excitation coil (5223) is wound on the second magnetic core (5222). The control terminal of the control system (8) is connected to the second excitation coil (5223). The upper core housing (5221) and the lower core housing (5224) are respectively provided with connecting holes (5226) for inserting the piston rod (515). A spring groove (5225) is provided between the upper shell (5221) and lower shell (5224) of the sphere core and the upper shell (5211) and lower shell (5212) of the buffer, relative to the position of the second return spring (525), and the second return spring (525) reciprocates within the spring groove (5225).

9. A UAV airborne recovery device based on magnetorheological buffering according to claim 8, characterized in that, The control system (8) includes a drive module (81) and a sensor module (82); The drive module (81) includes a current drive module (811) and a hydraulic drive module (821); the current drive module (811) is connected to the control terminals of the lead screw (3), the first excitation coil (5133) and the second excitation coil (5223) respectively; the hydraulic drive module (821) is connected to the control terminals of the recovery hydraulic cylinder (4) and the actuation hydraulic cylinder (7) respectively. The sensor module (82) includes a binocular vision optical measurement device (821) and an accelerometer (822), wherein the binocular vision optical measurement device (821) is used to identify the characteristics of the UAV model, speed, and attitude.

10. A method for unmanned aerial vehicle (UAV) airborne recovery based on magnetorheological buffering, characterized in that, A UAV airborne recovery device based on magnetorheological buffering as described in any one of claims 1-9 includes the following process: During the docking preparation phase, the control system (8) autonomously identifies the characteristics of the UAV model, speed and attitude. Based on the identified characteristics, it drives the mobile unit to adjust the relative positions of the recovery hydraulic cylinder (4) and the actuation hydraulic cylinder (7) on the fixed platform (1), and drives the actuation hydraulic cylinder (7) to adjust the pitch of the recovery hydraulic cylinder (4) and the extension length of the recovery hydraulic cylinder (4). At the same time, it adjusts the current in the magnetorheological universal buffer (5) according to the identified characteristics to control the viscosity of the magnetorheological fluid, so that the magnetorheological universal buffer (5) reaches the optimal docking state. During the docking process, the UAV approaches the adhesive device (6) at a certain relative speed and impacts the adhesive device and the magnetorheological universal buffer (5) along the axis. The magnetorheological universal buffer (5) dissipates the impact energy received and prepares for the next impact. During the recovery phase, the magnetorheological universal buffer (5) dampens the vibration of the UAV and ensures the stability of the UAV during the recovery phase. Then, the control system (8) drives the recovery hydraulic cylinder (4) to retract, so that the UAV is recovered into the bottom compartment of the mother machine. After the recovery is completed, the magnetorheological universal buffer (5) is de-energized and reset to prepare for a docking buffer task.

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