An unmanned aerial vehicle arresting device based on magneto-rheological fluid and a control method thereof

Abstract

This invention discloses a drone arresting device and its control method based on magnetorheological fluid, relating to the field of drone takeoff and landing technology. The invention includes: a shell, a central shaft, a damping device, a controller, a power supply, a clutch, a recovery motor, and a shell fixing device. This invention controls the rotational speed of the rotating shaft driven by the arresting cable through the combined action of inertial friction in the damping device and the magnetorheological fluid under closed-loop control. This effectively controls the speed curve of the arrested drone and stops applying load when the drone stops, reducing overload during the arresting run and improving the drone's service life.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) takeoff and landing technology in aerospace technology, and particularly to a UAV arresting device and its control method based on magnetorheological fluid. Background Technology

[0002] Arresting mechanisms are commonly used during short-distance landings of fixed-wing UAVs. During this process, it's crucial to control the magnitude of the arresting force to ensure the UAV can stop after a certain distance while minimizing its longitudinal overload. Traditional arresting devices utilize hydraulic damping, which requires hydraulic circuits and high-power motors, making it difficult to control in terms of size and portability. Furthermore, the control of the damping force is not precise enough to meet the demands for more precise control during the arresting process. Summary of the Invention

[0003] The embodiments of the present invention provide a drone arresting device and its control method based on magnetorheological fluid, which can reduce the size of the device to meet portability, and can also control the arresting force in real time during the drone arresting process.

[0004] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0005] In a first aspect, the embodiments of the present invention provide a UAV arresting device based on magnetorheological fluid, wherein the components of the UAV arresting device include: a shell (1), a damping device (2), a clutch (3), a controller (4), a recovery motor (5), a rotating shaft (6), a power supply (7), shell fixing bolts (8), and an arresting cable (9);

[0006] A damping device (2) is installed on the upper surface of the outer shell (1). A clutch (3) is also connected between the recovery motor (5) and the damping device (2). The rotating shaft (6) serves as a key connecting shaft to connect the outer shell (1), the damping device (2), the clutch (3), and the recovery motor (5) in sequence.

[0007] In the damping device (2), the device housing (2.3) is a hollow cylinder with an open top and a closed bottom. The top plate (2.1) is installed on the top of the device housing (2.3) and forms a sealed internal cavity with the device housing (2.3); the coil (2.2) is wound on the side of the device housing (2.3);

[0008] An inertial block (2.5) is installed in the internal cavity, and a magnetorheological fluid (2.8) is stored in the internal cavity;

[0009] The controller (4) is connected to the power supply (7). One set of power transmission interfaces of the power supply (7) is connected to the coil (2.2) of the damping device (2), and the other set of power transmission interfaces is connected to the recovery motor (5).

[0010] The side of the outer shell (1) is provided with an arresting cable outlet, wherein one end of the arresting cable (9) is wound around the rotating shaft (6) of a drone arresting device, and the other end extends out from the arresting cable outlet of the drone arresting device and is wound around the rotating shaft (6) of another drone arresting device.

[0011] Secondly, the control method provided by the embodiments of the present invention is used in a drone interception system, which includes two drone interception devices and a blocking cable. One end of the blocking cable is wound around the rotating shaft of one drone interception device, and the other end extends from the blocking cable outlet of the one drone interception device and is wound around the rotating shaft of the other drone interception device.

[0012] The method includes:

[0013] Connect the power supply (7) of each of the two UAV blocking devices and synchronize the controllers (4) of the two UAV blocking devices. Input the UAV mass and overload curve into the controller (4).

[0014] The operation of each drone interception device includes:

[0015] The speed sensor collects the extraction speed information of the arresting cable (9) and feeds it back to the controller (4). Before the UAV is unhooked, the clutch (3) is in the disengaged state. A rotatable cylinder (1.2) is installed on the arresting cable outlet of the UAV arresting device. The arresting cable (9) passes through the two rotatable cylinders (1.2) and extends out of the arresting cable outlet. The rotatable cylinder (1.2) is connected to the speed sensor.

[0016] The controller (4) controls the power supply (7) to output current to the coil (2.2) in the damping device (2) according to the extraction speed information;

[0017] After the drone is unhooked, the controller (4) controls the clutch (3) to close and starts the recovery motor (5) to reset the arresting cable (9).

[0018] This invention provides a drone arresting device and its control method based on magnetorheological fluid. It employs a combination of rotary magnetorheological fluid and friction-based damping, which, compared to traditional arresting devices, can successfully stop small and medium-sized drones within a specified distance and automatically reset them, meeting the requirements for continuous recovery. Furthermore, the drone arresting device is small in size, easy to transport, and facilitates rapid deployment. In addition, the closed-loop control of the magnetorheological fluid reduces drone overload and allows it to autonomously adapt to changes in drone mass within a certain range. Real-time control of the arresting force during the arresting process makes the changes in arresting force smoother, thereby reducing the impact of the sling and improving the drone's service life. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. 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.

[0020] Figures 1a to 1c The images shown are, in sequence, the front view, the left view, and the isometric test diagram of the main structural device of a single barrier unit provided in the embodiments of the present invention.

[0021] Figure 2 Provided for embodiments of the present invention Figures 1a to 1c The diagram shows the internal structure of the outer shell.

[0022] Figure 3 Provided for embodiments of the present invention Figures 1a to 1c A schematic diagram of the external structure of the damping device shown.

[0023] Figures 4a-4b Provided for embodiments of the present invention Figure 3 A schematic diagram of the internal structure of the damping device shown.

[0024] Figure 5 This is a schematic diagram of the arrangement of a drone interception device provided in an embodiment of the present invention;

[0025] Figure 6 Provided for embodiments of the present invention Figures 4a-4b The flowchart shown illustrates the operation of the damping device.

[0026] Figure 7 A flowchart of the control scheme provided in an embodiment of the present invention;

[0027] Figure 8This is a schematic diagram of a possible implementation of the control scheme provided in the embodiment of the present invention in a practical application. In this diagram, No. 1 refers to the No. 1 drone blocking device in the blocking system composed of two drone blocking devices, and No. 2 refers to the No. 2 drone blocking device in the blocking system composed of two drone blocking devices.

[0028] Figure 9 A schematic diagram illustrating the calculation of the eccentric yaw angle of a UAV provided in an embodiment of the present invention;

[0029] Figure 10 The graph showing the relationship between yield strength and magnetic induction intensity in a specific example provided in the embodiments of the present invention. Detailed Implementation

[0030] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Embodiments of the present invention will be described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in the specification of the present invention means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or couplings. The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items. When an element is referred to as being “fixed to” or “attached” to another element, it may be directly on the other element or there may be an intervening element. When an element is referred to as being “connected” to another element, it may be directly connected to the other element or there may be an intervening element. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items. It will be understood by one of ordinary skill in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the meaning consistent with their meaning in the context of the prior art and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0031] The purpose of this embodiment is to apply magnetorheological fluid (MRF) to drone arresting devices. Magnetorheological fluid is a novel smart material that, under the influence of an external magnetic field, exhibits a significant magnetorheological effect (MRE), with its yield stress and apparent viscosity changing by two to three orders of magnitude, displaying properties similar to a solid. When the external magnetic field is removed, the fluid reverts to its original flow properties, demonstrating a rapid and reversible transition between liquid and solid states within milliseconds. Therefore, this material possesses advantages such as fast response (milliseconds), good reversibility (returning to its initial state after the magnetic field is removed), and the ability to control the continuous change of its mechanical properties by adjusting the magnetic field strength. This magnetorheological fluid-based drone arresting device addresses the shortcomings of traditional arresting devices in terms of portability and control precision. After the drone's grappling hook engages, the required arresting force can be automatically and precisely adjusted, enabling the drone to complete a short-distance landing under relatively low overload, thus ensuring the drone's safety and extending its service life.

[0032] This invention provides a drone arresting device based on magnetorheological fluid, such as... Figures 1a to 1c As shown, it includes: housing (1), damping device (2), clutch (3), controller (4), recovery motor (5), rotating shaft (6), power supply (7), housing fixing bolts (8) and arresting cable (9).

[0033] A damping device (2) is installed on the upper surface of the outer shell (1). A clutch (3) is also connected between the recovery motor (5) and the damping device (2). The rotating shaft (6) serves as a key connecting shaft to connect the outer shell (1), the damping device (2), the clutch (3), and the recovery motor (5) in sequence.

[0034] In the damping device (2), the outer shell (2.3) is a hollow cylinder with an open top and a closed bottom. The top plate (2.1) is installed on the top of the outer shell (2.3) and forms a sealed internal cavity with the outer shell (2.3). The coil (2.2) is wound on the side of the outer shell (2.3).

[0035] An inertial block (2.5) is installed in the internal cavity, and magnetorheological fluid (2.8) is stored in the internal cavity. The magnetorheological fluid (2.8) fills the internal cavity but does not completely fill it. When the UAV arresting device is placed flat on the ground and is in a stationary state, the space filled by the magnetorheological fluid does not include the gap between the rotating disk (2.7) and the upper top plate (2.1).

[0036] Specifically, such as Figure 3As shown, the controller (4) is connected to the power supply (7), one set of power transmission interfaces of the power supply (7) is connected to the coil (2.2) of the damping device (2), and the other set of power transmission interfaces is connected to the recovery motor (5).

[0037] The outer casing (1) has a barrier cable outlet on its side. To form a complete barrier system, two barrier devices and one barrier cable (9) need to be arranged symmetrically. For example Figure 5 As shown, one end of the arresting cable (9) is coiled around the rotating shaft (6) of a drone arresting device, and the other end extends from the arresting cable outlet of this drone arresting device and is coiled around the rotating shaft (6) of another drone arresting device.

[0038] In this embodiment, as Figure 2 As shown, the outer casing (1) includes an outer casing fixing hole (1.1), a cylinder (1.2), a rotating shaft fixing sleeve (1.3), and an outer casing body (1.4). Each of the four corners of the upper surface of the outer casing (1) has an outer casing fixing hole (1.1), and each outer casing fixing hole (1.1) is screwed into a outer casing fixing bolt (8) so that the outer casing (1) can be fixed to the ground by the four outer casing fixing bolts (8). The outer casing fixing holes (1.1) can cooperate with the outer casing fixing bolts (8) to fix the entire barrier device.

[0039] The outer shell (1.4) is a cuboid. A rotating shaft fixing sleeve (1.3) is fixedly installed at the center of the inner bottom surface of the outer shell (1.4), and the rotating shaft (6) is inserted into the rotating shaft fixing sleeve (1.3). Two rotatable cylinders (1.2) are installed on the outlet of the arresting cable. The other end of the arresting cable (9) passes through the two rotatable cylinders (1.2) and extends out of the UAV arresting device. A speed sensor is connected to the rotatable cylinder (1.2). The speed sensor is used to collect the rotation speed information of the rotatable cylinder (1.2) and feed it back to the controller (4).

[0040] A controller (4) and a power supply (7) are fixedly mounted on the upper surface of the outer casing (1). The controller (4) is used to control the output current of the power supply (7), the opening or closing of the clutch (3), and the retraction of the motor (5). The controller (4) can be connected to other controllers (4) to achieve synchronization. The clutch (3) is connected to the rotating shaft (6). The arresting device includes a damping device (2), which is keyed to the rotating shaft (6) through a turntable in the damping device (2). Since at least two UAV arresting devices are required to form an arresting system, one UAV arresting device can be used as a synchronization reference, and the controllers of other UAV arresting devices can be synchronized with the controller of this one UAV arresting device.

[0041] In this embodiment, as Figure 3As shown in Figure 4, the damping device (2) also includes: a fixed shaft (2.4), a friction plate (2.6), and a sealing layer (2.9).

[0042] A sealing layer (2.9) covers the inner wall of the device housing (2.3) and the lower surface of the upper top plate (2.1). After the upper top plate (2.1) is installed on top of the device housing (2.3), the sealing layer (2.9) encloses and forms the sealed internal cavity. The upper top plate (2.1) and the device housing (2.3) together constitute the housing of the damping device. To ensure the sealing of the damping device (2) and the preservation of its rotational freedom when the rotating shaft (6) passes through it, rotational seals are added at the openings in the upper top plate (2.1) and the device housing (2.3).

[0043] An inertial block (2.5) and a rotating disk (2.7) are installed in the internal cavity. The rotating disk (2.7) is fixed to the rotating shaft (6), and the inertial block (2.5) is fixed to the rotating disk (2.7) via a fixed shaft (2.4). The inertial block (2.5) is fixed on the rotating shaft inside the rotating disk (2.7) and can only rotate in one direction. There is a key on the fixed shaft (2.4), and the fixing hole on the inertial block (2.5) has a designed extra space, so that the inertial block (2.5) can only rotate within a certain range. When the device is running, the rotating shaft (6) drives the rotating disk (2.7) and the inertial block (2.5) on it to move, generating viscous damping with the magnetorheological fluid and compressing the magnetorheological fluid into the gap to generate damping. When the rotation speed reaches a certain level, the inertial block (2.5) moves around the fixed shaft and compresses the friction plate (2.6) to generate friction damping.

[0044] In this embodiment, the diameter of the rotating disk (2.7) is slightly smaller than the inner diameter of the device housing (2.3), and there is a gap between the rotating disk (2.7) and the upper top plate (2.1). Magnetorheological fluid (2.8) is stored between the rotating disk (2.7) and the bottom of the device housing (2.3). A friction plate (2.6) is adhered to the outer surface of the inertial block (2.5). Both the inertial block (2.5) and the friction plate (2.6) are made of non-magnetic metal. In a preferred embodiment, the diameter of the rotating disk (2.7) is 138 mm, and the inner diameter of the device housing (2.3) is 140 mm.

[0045] In practical applications, two arresting devices and an additional arresting cable (9) need to be symmetrically arranged. The additional arresting cable can be connected to the arresting cables (9) of the two arresting devices in a ring. The arresting cable (9) is pulled out from the cylinder (1.2), and the speed sensor feeds back the movement speed of the arresting cable (9) to the controller (4). The controller (4) adjusts the current of the power supply (7) to make the coil (2.2) reach a suitable magnetic field, thereby making the magnetorheological fluid reach a suitable viscosity, and under the pressure of the inertial block (2.5), it enters the rotating disk (2.7) and the upper plate (2.1) to generate a damping force. On the other hand, when the speed reaches a certain point, the friction plate (2.6) is squeezed onto the device shell (2.3) by the centrifugal force of the inertial block (2.5) to provide frictional damping force. After the UAV is unhooked, the controller (4) controls the clutch (3) to engage, the recovery motor (5) starts, and the arresting device is reset.

[0046] In a preferred embodiment, the inertial block (2.5) is made of copper;

[0047] The friction pad (2.6) is made of resin-based asbestos-plant fiber interwoven fabric with a mesh pattern on the surface.

[0048] The magnetorheological fluid (2.8) comprises: a base liquid, a dispersed phase, and an additive; wherein the base liquid is vegetable oil or mineral oil; the dispersed phase is carbonyl iron powder with a size of 3 to 5 micrometers and a particle volume fraction of 35%; and the additive is oleic acid.

[0049] This embodiment also provides a control method for a drone interception system, which includes two drone interception devices and a blocking cable. Before the drone is intercepted by the cable, the interception devices are arranged and fixed. One end of the blocking cable is wound around the rotating shaft of one drone interception device, and the other end extends from the blocking cable outlet of one drone interception device and is wound around the rotating shaft of the other drone interception device.

[0050] The method includes:

[0051] Connect the power supply (7) of each of the two UAV blocking devices and synchronize the controllers (4) of the two UAV blocking devices. Input the UAV mass and overload curve into the controller (4).

[0052] After the hooks engage, the arresting cable (9) pulls the arresting cables (9) coiled in the two arresting devices out through the outlet on the outer shell (1). The operation process of each UAV arresting device includes:

[0053] The speed sensor collects the extraction speed information of the arresting cable (9) and feeds it back to the controller (4). Before the UAV unhooks, the clutch (3) is in the disengaged state. A rotatable cylinder (1.2) is installed on the arresting cable outlet of the UAV arresting device. The arresting cable (9) passes through the two rotatable cylinders (1.2) and extends out of the arresting cable outlet. The rotatable cylinder (1.2) is connected to the speed sensor. The speed sensor on the outlet cylinder (1.2) of the outer shell (1) feeds back the movement speed of the arresting cable (9) to the controller (4).

[0054] The controller (4) calculates the adjustment current based on the relationship between damping force, rotational speed, and coil current, and then controls the power supply (7) to output the adjustment current to the coil (2.2) in the damping device (2);

[0055] After the drone is unhooked, the controller (4) controls the clutch (3) to close and starts the recovery motor (5) to reset the arresting cable (9).

[0056] In this process, the controller (4) calculates and controls the power supply (7) to generate a suitable magnetic field in the coil (2.2) of the damping device (2). The rotating disk (2.7) in the damping device (2) rotates under the drive of the rotating shaft (6), thereby generating viscous resistance between the inertial block (2.5) and the magnetorheological fluid, and at the same time, it compresses the magnetorheological fluid into the gap between the rotating disk (2.7) and the outer shell (1). When the rotation speed reaches a certain level, the friction plate (2.6) is squeezed to the inside of the outer shell (2.3) of the device under the action of the centrifugal force of the inertial block (2.5) to generate frictional damping. When the UAV is unhooked, the controller (4) controls the clutch (3) to close, opens the recovery motor (5), resets the arresting device, and completes the entire short-distance landing process.

[0057] Specifically, the controller (4) controls the current output of the power supply (7) to the coil (2.2) in the damping device (2) according to the extraction speed information, including: inputting the mass and acceleration curve of the UAV to the controller (4), and calculating the current output of the power supply (7) to the coil (2.2) in the damping device (2) according to the extraction speed information and the mass and acceleration curve of the UAV. For example: the controller (4) can be based on the PID control algorithm; the input of the controller (4) is the arresting cable (9) pull-out speed fed back by the arresting cable exit speed sensor, the mass of the UAV and the required acceleration curve; the controlled parameters are the current of the coil (2.2), the switch of the clutch (3) and the power supply switch of the recovery motor (5); in the default state, the clutch (3) is open; when working, the controller (4) calculates the current arresting force and the required arresting force according to the input parameters and distributes them to each arresting device; after the UAV is unhooked (i.e. the hook and cable are separated), the controller (4) closes the clutch (3), turns on the recovery motor (5) to automatically recover the arresting cable (9), and then opens the clutch (3);

[0058] For example, Figures 4a-4b The drone interception device shown can achieve the following: Figure 6 The usage process is shown below:

[0059] (1) Before use, first complete the arrangement of the barrier device, turn on and synchronize the controller; after confirming that all control connections are completed, turn on the power, pay attention to the power level, and confirm that the clutch is not closed; input the mass of the barrier machine used, the required acceleration curve and the distance between the two devices into the controller; the device is now ready.

[0060] (2) After use, record the power supply, confirm that the clutch is not closed, turn off the power and controller; and finally put away the entire set of blocking system.

[0061] Furthermore, such as Figure 7 and Figure 8 The diagram illustrates the controller's control flow. The damping force provided on one side includes frictional damping force and the damping force provided by the rotation of the inertial block in the magnetorheological fluid. After receiving the feedback speed, the controller calculates the rotational speed of the rotating shaft to confirm the rotational speed of the inertial block, and calculates the frictional damping and the damping force provided by the magnetorheological fluid at this time. Simultaneously, it compares the speeds on both sides with the distance input between the two devices to obtain the eccentricity, and compares it with the previous state to determine the yaw angle. Finally, based on the required acceleration curve, aircraft mass, eccentricity, and yaw angle, it calculates the required damping force on one side, thereby calculating the required rotational speed of the rotating shaft, and allocates it to a single unit / group of devices, controlling the power output. When the speed returns to zero and the hook and cable separate, the controller controls the clutch to close, the recovery motor to open, and the arresting cable to be re-wound inside the outer casing. Finally, the clutch is disengaged. For example: Figure 9The diagram shown illustrates the calculation of eccentricity and yaw angle. b represents the arresting gear spacing. Since the rope tension is much greater than the arresting weight, the influence of rope gravity is ignored. At this point, l... t,1 ,l t,2 This indicates the length of the arresting cable that has been pulled out by arresting machines 1 and 2 at the current time;

[0062] l t-Δt,1 ,l t-Δt,2 The length of the arresting cables for both drone arresting device 1 and drone arresting device 2 that had been pulled out at the previous time point is calculated using the following formula:

[0063]

[0064] Where v1 and v2 represent the extraction velocities of the arresting cables on both sides, t represents the current time point, and Δt represents the step size of the integration operation.

[0065] The eccentricity at these two moments can be expressed as:

[0066]

[0067]

[0068] The tangent of the yaw angle can be expressed as:

[0069]

[0070] The magnetic flux density at any point under an N-turn coil at any time can be expressed as:

[0071]

[0072] In the formula, μ0 is the permeability; R is the average radius of the coil; N is the number of turns of the coil; I is the current output from the power supply (7) to the coil; the relationship between the yield strength and magnetic induction intensity formed by the magnetorheological fluid used in the embodiment is as follows: Figure 10 As shown

[0073] In the embodiment, the damping force F total Including frictional damping force F friction Magnetorheological fluid viscous damping force and magnetorheological hydraulic differential damping force The calculation method is as follows:

[0074]

[0075] F friction =3μ friction F N =3m Inertia block μ friction ω 2 R Inertia block

[0076]

[0077]

[0078] In the formula, m Inertia block The mass of the inertial block is μ. friction ω is the coefficient of friction between the friction plate and the housing; R is the angular velocity of the shaft; Inertia block The distance between the inertial block and the axis of rotation; τ is the viscous damping coefficient without an external magnetic field; c is a constant; L is the static magnetorheological fluid depth; h is the gap width; τ H This represents the yield strength of the magnetorheological fluid. The above formulas and... Figure 10 This can demonstrate the relationship between damping force, rotational speed, and coil current.

[0079] Figure 8 The input quantity of the medium current adjustment unit is

[0080]

[0081] In the formula, K p ,K i ,K d These are three types of PID unit parameters; ω(t) is the current speed; ω required (t) represents the required rotational speed, t represents time, τ represents a temporary variable, and ω(τ) represents the current angular velocity corresponding to τ. required (τ) represents the required angular velocity corresponding to τ. The adjustment current is calculated using the aforementioned relationship between damping force, rotational speed, and coil current.

[0082] The main advantages of this embodiment are: it employs a combination of rotary magnetorheological fluid and frictional damping, which, compared to traditional arresting devices, can successfully stop small and medium-sized UAVs within a specified distance and automatically reset them, meeting the requirements for continuous recovery. Furthermore, the UAV arresting device is small in size, easy to transport, and facilitates rapid deployment. Additionally, the closed-loop control of the magnetorheological fluid reduces UAV overload and allows it to autonomously adapt to changes in UAV mass within a certain range. Real-time control of the arresting force during the arrest process makes the changes in arresting force smoother, thereby reducing the impact of the sling and increasing the UAV's service life.

[0083] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. The above descriptions are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A control method, characterized in that, The control method is used in a drone arresting system, which includes two drone arresting devices based on magnetorheological fluid and an arresting cable. One end of the arresting cable is wound around the rotating shaft of one drone arresting device, and the other end extends from the arresting cable outlet of the one drone arresting device and is wound around the rotating shaft of the other drone arresting device. The method includes: Connect the power supply (7) of each of the two UAV blocking devices and synchronize the controllers (4) of the two UAV blocking devices. Input the UAV mass and overload curve into the controller (4); The operation of each drone interception device includes: The speed sensor collects the extraction speed information of the arresting cable (9) and feeds it back to the controller (4). Before the UAV is unhooked, the clutch (3) is in the disengaged state. A rotatable cylinder (1.2) is installed on the arresting cable outlet of the UAV arresting device. The arresting cable (9) passes through the two rotatable cylinders (1.2) and extends out of the arresting cable outlet. The rotatable cylinder (1.2) is connected to the speed sensor. The controller (4) calculates the adjustment current based on the relationship between damping force, rotational speed and coil current, and then controls the power supply (7) to output the adjustment current to the coil (2.2) in the damping device (2); When the drone is unhooked, the controller (4) controls the clutch (3) to close and starts the recovery motor (5) to reset the arresting cable (9); The relationship between damping force, rotational speed, and coil current includes: , , , ,in, Indicates damping force. Indicates frictional damping force. This represents the viscous damping force of the magnetorheological fluid. This represents the differential damping force of the magnetorheological fluid. The mass of the inertial block; The friction coefficient is the coefficient of friction between the friction plate and the outer casing of the device. The angular velocity of the shaft; The distance between the inertial block and the axis of rotation; This is the viscous damping coefficient without an external magnetic field; It is a constant; The static magnetorheological fluid depth; This refers to the gap width; It represents the yield strength of the magnetorheological fluid.

2. The control method according to claim 1, characterized in that, The components of the UAV arresting system based on magnetorheological fluid include: a shell (1), a damping device (2), a clutch (3), a controller (4), a recovery motor (5), a rotating shaft (6), a power supply (7), shell fixing bolts (8), and an arresting cable (9). A damping device (2) is installed on the upper surface of the outer shell (1). A clutch (3) is also connected between the recovery motor (5) and the damping device (2). The rotating shaft (6) serves as a key connecting shaft to connect the outer shell (1), the damping device (2), the clutch (3), and the recovery motor (5) in sequence. In the damping device (2), the device housing (2.3) is a hollow cylinder with an open top and a closed bottom. The top plate (2.1) is installed on the top of the device housing (2.3) and forms a sealed internal cavity with the device housing (2.3). The coil (2.2) is wound on the side of the device housing (2.3). An inertial block (2.5) is installed in the internal cavity, and a magnetorheological fluid (2.8) is stored in the internal cavity. The controller (4) is connected to the power supply (7). One set of power transmission interfaces of the power supply (7) is connected to the coil (2.2) of the damping device (2), and the other set of power transmission interfaces is connected to the recovery motor (5). The side of the outer shell (1) is provided with an arresting cable outlet, wherein one end of the arresting cable (9) is coiled around the rotating shaft (6) of a drone arresting device, and the other end extends out from the arresting cable outlet of this drone arresting device and is coiled around the rotating shaft (6) of another drone arresting device.

3. The control method according to claim 2, characterized in that, The outer casing (1) includes an outer casing fixing hole (1.1), a cylinder (1.2), a rotating shaft fixing sleeve (1.3), and an outer casing body (1.4). The outer shell body (1.4) is a cuboid. A rotating shaft fixing sleeve (1.3) is fixedly installed at the center of the inner bottom surface of the outer shell body (1.4). The rotating shaft (6) is inserted into the rotating shaft fixing sleeve (1.3), and the axial movement freedom of the rotating shaft (6) is fixed by the rotating shaft fixing sleeve (1.3). Two rotatable cylinders (1.2) are installed on the outlet of the arresting cable. The other end of the arresting cable (9) passes through the two rotatable cylinders (1.2) and extends out of the UAV arresting device. A speed sensor is connected to the rotatable cylinder (1.2) to collect the rotational speed information of the rotatable cylinder (1.2) and feed it back to the controller (4).

4. The control method according to claim 2, characterized in that, The damping device (2) also includes: a fixed shaft (2.4), a friction plate (2.6), and a sealing layer (2.9); The sealing layer (2.9) is located between the device housing (2.3) and the upper top plate (2.1). After the upper top plate (2.1) is installed on the top of the device housing (2.3), the sealing internal cavity is formed inside. An inertial block (2.5) and a rotating disk (2.7) are installed in the internal cavity. The rotating disk (2.7) is fixed to the rotating shaft (6), and the inertial block (2.5) is fixed on the rotating disk (2.7) by a fixed shaft (2.4).

5. The control method according to claim 4, characterized in that, The diameter of the rotating disk (2.7) is slightly smaller than the inner diameter of the device housing (2.3), and there is a gap between the rotating disk (2.7) and the upper top plate (2.1); The magnetorheological fluid (2.8) is stored between the rotating disk (2.7) and the bottom of the device housing (2.3).

6. The control method according to claim 5, characterized in that, The diameter of the rotating disk (2.7) is 138 mm, and the inner diameter of the device housing (2.3) is 140 mm.

7. The control method according to claim 4, characterized in that, Friction pads (2.6) are attached to the outer surface of the inertial block (2.5); Both the inertial block (2.5) and the friction plate (2.6) are made of non-magnetic metal.

8. The control method according to claim 1 or 7, characterized in that, The inertial block (2.5) is made of copper; The friction pad (2.6) is made of a blend of resin-based asbestos yarn and plant fiber yarn, and a mesh pattern is formed on the surface of the blend.

9. The control method according to claim 1 or 7, characterized in that, The components of the magnetorheological fluid (2.8) include: base fluid, dispersion medium and additives; The base liquid is made of vegetable oil or mineral oil; The dispersed material is carbonyl iron powder with a size of 3 to 5 micrometers, and the particle volume fraction of the dispersed material is 35%. The additive used is oleic acid.

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