An unmanned aerial vehicle arresting system based on a magnetic powder brake and a control method thereof

Abstract

The application discloses a UAV arresting system based on a magnetic powder brake and a control method thereof, and relates to the field of UAV take-off and landing technology in aerospace technology. The UAV arresting system can be installed and maintained in a limited space, and can adjust the arresting torque size in real time based on unknown factors (such as tailwind and rainfall) in an actual arresting process, so that the arresting distance and overload can be accurately controlled. The UAV arresting system comprises an arresting cable and two arresting devices connected at two ends of the arresting cable. The arresting device comprises a split shell, a power supply and a controller, a recovery motor, a magnetic powder clutch, a transmission shaft, a hook, a winch and a magnetic powder brake. Through the braking torque of the magnetic powder brake under adaptive control, the rotating speed of the winch is controlled, so that the releasing speed of the arresting cable and the speed curve of the UAV are controlled.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) take-off and landing technology in aerospace technology, and in particular to a UAV arresting device and its control method based on a magnetic powder brake. Background Technology

[0002] Arresting and recovery is a typical arresting method for fixed-wing UAVs. Traditional UAV arresting mechanisms use friction damping or hydraulic damping. Friction dampers cannot control the arresting torque in real time, resulting in significant UAV overload and reduced lifespan. Hydraulic dampers are bulky and heavy, and cannot be easily moved, making them unsuitable for temporary UAV take-off and landing platforms. Mobile UAV take-off and landing platforms represent a significant development direction for UAV platforms. These platforms, limited by their smaller size, have high requirements for arresting distance and overload; therefore, precise control of the arresting torque is crucial for improving UAV platform performance. Summary of the Invention

[0003] To address the above problems, this invention proposes a drone arresting system and its control method based on a magnetic powder brake. This system can be installed and maintained in a limited space, and can adjust the arresting torque in real time based on unknown factors (tailwind, rainfall, etc.) during the actual arresting process, thereby achieving precise control of the arresting distance and overload.

[0004] The technical solution of the present invention is as follows: the UAV arresting system includes an arresting cable 700 and two arresting devices connected to both ends of the arresting cable 700. The arresting device includes a separable shell 100, a power supply and controller 200, a recovery motor 300, a magnetic powder clutch 400, a drive shaft 500, a hook 600, a winch 800, and a magnetic powder brake 900.

[0005] The recycling motor 300, power supply and controller 200 are all fixedly installed in the separable housing 100. The housing of the magnetic powder clutch 400 and the housing of the magnetic powder brake 900 are also fixedly installed in the separable housing 100. The recycling motor 300, magnetic powder clutch 400 and magnetic powder brake 900 are coaxially arranged. The input end of the magnetic powder clutch 400 is connected to the output shaft of the recovery motor 300, and the two ends of the transmission shaft 500 are respectively connected to the output ends of the magnetic powder clutch 400 and the output ends of the magnetic powder brake 900. In this way, when the magnetic powder clutch 400 is de-energized and the magnetic powder brake 900 is energized, the transmission shaft 500 will rotate under the resistance of the magnetic powder brake 900, thereby decelerating and braking the extension of the arresting cable 700 after it is connected. When the magnetic powder clutch 400 is energized and the magnetic powder brake 900 is de-energized, the output shaft of the recovery motor 300 and the transmission shaft 500 remain linked, so that the transmission shaft 500 can rotate under the drive of the recovery motor 300, thereby actively retracting the arresting cable after it is connected.

[0006] The power supply and controller 200 are respectively connected to the recycling motor 300, the magnetic powder clutch 400 and the magnetic powder brake 900;

[0007] As a mechanism for connecting the arresting cable 700, the winch 800 is fixedly mounted on the drive shaft 500, and the hook 600 is fixedly mounted on the separable housing 100. The separable housing 100 has an opening located next to the winch 800. Thus, the arresting cable 700 is driven by the winch 800, which rotates synchronously with the drive shaft 500. The hook 600 serves as the fixing point of the arresting cable 700, and the opening serves as the entry and exit space for the arresting cable 700.

[0008] The two ends of the arresting cable 700 are respectively inserted into the two arresting devices through openings, and after being wound around the two winches 800 several times, they are fixedly connected to the hooks 600 in the two arresting devices.

[0009] Furthermore, the recycling motor 300, magnetic powder clutch 400, drive shaft 500, winch 800 and magnetic powder brake 900 are coaxially arranged, and the drive shaft 500 serves as a key connecting shaft to sequentially connect the magnetic powder brake 900, winch 800 and magnetic powder clutch 400.

[0010] Furthermore, the power supply and controller 200 is an integrated design and has a hollow cylindrical shape. The power supply and controller 200 has three sets of power transmission lines, which are respectively connected to the recycling motor 300, the magnetic powder clutch 400 and the magnetic powder brake 900.

[0011] Furthermore, the detachable outer shell 100 is a hollow cylinder, comprising a fixed surface 101 and a detachable surface 102. The fixed surface 101 includes a circular upper surface, a circular lower surface, and a semi-cylindrical side surface, and has an opening for the arresting cable 700 to be led out. The detachable surface 102 is a semi-cylindrical shell. The fixed surface 101 and the detachable surface 102 are connected by bolts on the lugs. The bottom of the sides of the fixed surface 101 and the detachable surface 102 respectively have bolt holes for connecting to the ground.

[0012] Furthermore, the drive shaft 500 is equipped with a speed sensor, and the magnetic powder brake 900 is equipped with a torque sensor, which respectively collects speed signals and torque signals, and has signal cables connected to the power supply and controller 200 as feedback signals for the controller.

[0013] The operation of the drone interception system includes:

[0014] Power is switched on and controller 200 is connected. The ideal arresting torque curve is determined based on factors such as the UAV's landing weight, arresting distance, and maximum overload, and then input into the controller. At this time, the power to the magnetic powder clutch 400 and the recovery motor 300 is disconnected, and the magnetic powder brake 900 is energized, ready to start the arresting process. After the UAV completes grounding and hooking, the magnetic powder brake 900 receives current according to the pre-input ideal arresting torque curve, and the UAV's arresting torque is adjusted in real time.

[0015] Throughout the arresting process, the controller adjusts the target's arresting torque in real time based on the difference between the current speed and the ideal speed of the UAV, achieving closed-loop control of the arresting distance and UAV overload; after the arresting process is completed, the magnetic powder brake 900 is de-energized, and the magnetic powder clutch 400 and the recovery motor 300 are energized to achieve the recovery of the arresting cable.

[0016] In the above description, the controller is a PID-based outer loop controller for stopping and compensating force, and the magnetic powder brake 900 has a PID-based outer loop controller for stopping and compensating force. The inner loop controller for the resisting torque of the adaptive controller.

[0017] To compensate for the impact of factors such as tailwind, changes in drone mass, and ground slope on the drone's arresting distance, an outer-loop controller for arresting compensation force based on PID control is designed; the input of the controller is the current winch rotation angle. Winch rotation angle in the ideal curve The difference; through control quantity To achieve compensation for the stopping torque:

[0018] ;

[0019] in , , These are proportional, integral, and differential gains, respectively.

[0020] To achieve the stopping torque control of the magnetic particle brake, a design based on The adaptive controller's inner loop controller for the braking torque is designed to address the hysteresis characteristics of the magnetic particle brake and the inconsistencies generated during its operation; the aforementioned... The input of the inner loop controller of the adaptive controller's resistive torque is , For the pre-input braking torque curve, For frictional torque; the one based on The inner loop controller of the adaptive controller for the braking torque consists of three parts: a state predictor, an adaptive law, and a control law. It is known that an ideal magnetic powder brake, neglecting time delay, satisfies the following transfer function for a first-order system:

[0021] ;

[0022] in To output braking torque, For input current, For brake gain, It is a time constant;

[0023] Converting to state-space equations yields:

[0024] ;

[0025] The state predictor satisfies the following equation:

[0026] ;

[0027] in For the state variables of the state predictor, For a given input gain, This is an estimate of the matching uncertainty of the magnetic particle brake system. The estimated amount of input disturbance for the magnetic particle brake corresponds to the delay characteristics of the magnetic particle brake;

[0028] The adaptive rule satisfies the following equation:

[0029] ;

[0030] in For adaptive rate, For projection operators, , satisfy:

[0031] , ;

[0032] The control law satisfies the following equation:

[0033] ;

[0034] in For input signal, satisfy:

[0035] .

[0036] This invention controls the rotation speed of the winch by using the braking torque of a magnetic powder brake under adaptive control, thereby controlling the release speed of the arresting cable and the speed curve of the UAV. The arresting torque curve can be comprehensively adjusted according to the mass of the UAV, the maximum load, and the arresting distance to balance the arresting distance and the lifespan of the UAV. Attached Figure Description

[0037] Figure 1 This is a front view of a single blocking device provided in an embodiment of the present invention;

[0038] Figure 1-1 This is a left view of a single blocking device provided in an embodiment of the present invention;

[0039] Figure 2 This is an isometric view of a single blocking device according to an embodiment of the present invention;

[0040] Figure 2-1 This is an isometric view of the fixed surface of the outer shell of a single blocking device according to an embodiment of the present invention after removal;

[0041] Figure 3 This is a schematic diagram of the detachable outer shell structure according to an embodiment of the present invention. Figure 1 ;

[0042] Figure 3-1 This is a schematic diagram of the detachable outer shell structure according to an embodiment of the present invention. Figure 2 ;

[0043] Figure 4 This is a schematic diagram illustrating a usage scenario of an embodiment of the present invention;

[0044] Figure 5 This is a structural diagram of the outer loop controller for UAV arresting compensation force based on PID control according to an embodiment of the present invention;

[0045] Figure 6 This is a typical UAV interception displacement curve according to an embodiment of the present invention;

[0046] Figure 7 This is based on the embodiments of the present invention. Diagram of the inner loop controller structure for the magnetic powder brake's stopping torque in an adaptive controller;

[0047] Figure 8This is a typical UAV arresting resistance curve according to an embodiment of the present invention;

[0048] In the diagram, 100 is the detachable outer casing, 200 is the power supply and controller, 300 is the recovery motor, 400 is the magnetic powder clutch, 500 is the drive shaft, 600 is the hook, 700 is the arresting cable, 800 is the winch, and 900 is the magnetic powder brake. Detailed Implementation

[0049] To clearly illustrate the technical features of this patent, the following detailed description is provided through specific embodiments and in conjunction with the accompanying drawings.

[0050] The purpose of this embodiment is to apply a magnetic particle brake to an arresting device for unmanned aerial vehicles (UAVs). A magnetic particle brake is a type of brake that utilizes electromagnetic principles to transmit torque through magnetic particles. It features approximately linear torque transmission with excitation current and a relatively fast response; however, the response time is not negligible and must be considered in the controller design to improve control quality. Precise control cannot be achieved directly using a linear controller. This embodiment utilizes a PID-based arresting compensation force outer loop controller and a... The adaptive controller, combined with the inner loop controller for resisting torque, effectively addresses the delay characteristics of the magnetic powder brake and the unknowns caused by the external environment in practical applications.

[0051] Single drone interception device, such as Figure 2 As shown, it includes a detachable housing 100, a power supply and controller 200, a recovery motor 300, a magnetic powder clutch 400, a drive shaft 500, a hook 600, a restraining cable 700, a winch 800, and a magnetic powder brake 900.

[0052] A magnetic powder brake is installed on the lower surface of the fixed surface 101 of the split housing, and a magnetic powder clutch 400, a power supply and controller 200 and a hook 600 are installed on the side. The magnetic powder clutch 400 is connected between the recovery motor 300 and the winch. The drive shaft 500 is used as a key connecting shaft to sequentially connect the magnetic powder brake 900, the winch 800 and the magnetic powder clutch 400.

[0053] The arresting cable 700 is fixed to the hook 600 and wound around the winch 800 in multiple turns. It is led out through the opening of the split outer shell fixing surface 101 and wound around the winch 800 of the UAV arresting device with a symmetrical shape at the other end, and fixed to the hook 600.

[0054] The upper movable shaft of the magnetic powder clutch 400 is keyed to the output shaft of the recovery motor 300, and the lower movable shaft is keyed to the transmission shaft 500. The upper and lower movable shafts are engaged and rotate simultaneously when the magnetic powder clutch is energized, and are separated when the power is off, and each rotates freely. The magnetic powder clutch 400 is connected to the separable housing 100 through a bracket.

[0055] The power supply and controller 200 is an integrated design and has a hollow cylindrical shape. The power supply and controller 200 has three sets of power transmission lines, which are connected to the recycling motor 300, the magnetic powder clutch 400 and the magnetic powder brake 900 respectively.

[0056] The drive shaft 500 is equipped with a speed sensor, and the magnetic powder brake 900 is equipped with a torque sensor. The speed signal and torque signal are collected respectively, and the signal cable is connected to the power supply and controller 200 as the feedback signal of the controller.

[0057] like Figure 3 As shown, the detachable housing is made of aluminum, 10mm thick, and consists of a fixed surface 101 and a detachable surface 102. The fixed surface 101 includes a semi-cylindrical surface and circular upper and lower bottom surfaces. The cylindrical surface has an opening for the arresting cable to pass through. The inner diameter of the lower bottom surface is slightly larger than the outer diameter of the magnetic powder brake 900. The detachable surface 102 includes a semi-cylindrical surface. The fixed surface 101 and the detachable surface 102 are connected by bolts on their respective lugs. The equipment can be maintained by removing the bolts and the detachable surface. The magnetic powder brake is mounted on the lower surface of the fixed surface 101 of the detachable housing. A magnetic powder clutch 400, a power supply and controller 200, and a hook 600 are mounted on the side. The magnetic powder clutch 400 connects the recovery motor 300 to the winch. The drive shaft 500 serves as a key connecting shaft, sequentially connecting the magnetic powder brake 900, the winch 800, and the magnetic powder clutch 400. The arresting cable 700 is fixed to the hook 600 and wound around the winch 800 in multiple turns. It is led out through the opening of the split housing fixing surface 101 and fixed to the hook 600.

[0058] This embodiment also provides a control method for an unmanned aerial vehicle (UAV) interception system, such as... Figure 4 As shown, the UAV arresting system includes a left arresting machine, a right arresting machine, an arresting cable 700, and a plastic pad. The left and right arresting machines are mounted on a surface lower than the runway. The extension height of the cable 700 can be adjusted by changing the winding height of the cable on the winch 800. The two arresting machines are symmetrically designed to ensure that the arresting cable 700 is perpendicular to the UAV's descent direction. The arresting cable 700 is made of nylon and is wound a specified number of times around the winch 800 on both sides of the arresting device during the entire arresting process. A circular plastic pad is installed at the hook-lock point between the arresting cable 700 and the UAV arresting hook, ensuring that the arresting cable has a certain height off the ground and is at the same contact height with the UAV arresting hook. For UAV arresting missions with high reliability requirements, multiple independent UAV arresting systems can be set up, ensuring a certain distance between each arresting cable.

[0059] The operation of the drone interception device includes:

[0060] Connect the power supply and controller 200, open the controller module, determine the ideal arresting torque curve based on factors such as the UAV's landing weight, arresting distance, and maximum overload, and input it into the controller. At this time, the power to the magnetic powder clutch 400 and the recovery motor 300 is disconnected, and the magnetic powder brake 900 is energized, ready to begin arresting; wait for the UAV to complete grounding, and after the UAV has grounded and hooked up, based on... The inner loop controller of the magnetic powder brake 900 of the adaptive controller inputs current to the magnetic powder brake 900 according to the pre-input ideal arresting torque curve, and adjusts the UAV arresting torque in real time. During the entire arresting process, the outer loop controller of the UAV arresting compensation force based on PID control adjusts the target arresting torque in real time according to the difference between the current UAV distance and the ideal distance, realizing closed-loop control of the arresting distance and UAV overload. After the arresting process is completed, the magnetic powder brake 900 is de-energized, and the magnetic powder clutch 400 and the recovery motor 300 are energized to realize the recovery of the arresting cable.

[0061] The control law used in the control method includes:

[0062] like Figure 5 As shown, to compensate for the impact of factors such as tailwind, changes in drone mass, and ground slope on the drone's arresting distance, a PID-based compensation arresting torque controller is designed; the input to this controller is the current winch rotation angle. The winch rotation angle is located on the ideal curve. The difference; through control quantity To achieve compensation for the stopping torque:

[0063] ,

[0064] in , , These are proportional, integral, and differential gains, respectively.

[0065] Input ideal stopping curve displacement This can be obtained through experiments and dynamic simulations. Figure 6 This is the arresting displacement curve of a 20kg drone; and the current displacement... The displacement can be obtained using the following formula: Ignoring eccentric arresting, if the displacement obtained by the sensor on one side of the arresting gear is... The initial lateral length of the arresting cable is Then we have:

[0066] .

[0067] like Figure 7 As shown, in order to achieve the stopping torque control of the magnetic powder brake, a design based on... The adaptive controller for the magnetic particle brake's stopping torque takes into account the hysteresis characteristics of the magnetic particle brake and the inconsistencies generated during its operation; the controller input is... , The pre-input braking torque curve can be obtained through experiments and dynamic simulations. Figure 8 Arresting force for a 20kg drone Curve, if the radius of the arresting cable wound on the winch is known. Then it can be obtained by the following formula:

[0068] ;

[0069] In the above, The output of the PID-controlled compensation resistance torque controller For frictional torque, The damping coefficient between the arresting cable and the winch satisfies the following equation:

[0070] ;

[0071] The controller consists of three parts: a state predictor, an adaptive law, and a control law. It is known that an ideal magnetic particle brake, neglecting time delay, satisfies the following transfer function for a first-order system:

[0072] ;

[0073] in To output braking torque, For input current, For brake gain, It is a time constant;

[0074] Converting to state-space equations yields:

[0075] ;

[0076] The state predictor satisfies the following equation:

[0077] ;

[0078] in For the state variables of the state predictor, For a given input gain, This is an estimate of the matching uncertainty of the magnetic particle brake system. The estimated amount of input disturbance for the magnetic particle brake corresponds to the delay characteristics of the magnetic particle brake;

[0079] The adaptive rule satisfies the following equation:

[0080] ;

[0081] in For adaptive rate, For projection operators, , satisfy:

[0082] ;

[0083] The control law satisfies the following equation:

[0084] ;

[0085] in For input signal, satisfy:

[0086] .

[0087] There are many specific ways to implement this invention. The above description is only a preferred embodiment of this invention. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of this invention, and these improvements should also be considered within the scope of protection of this invention.

Claims

1. A drone arresting system based on magnetic powder brake, characterized in that, The UAV arresting system includes an arresting cable (700) and two arresting devices connected to both ends of the arresting cable (700). The arresting devices include a separable housing (100), a power supply and controller (200), a recovery motor (300), a magnetic powder clutch (400), a drive shaft (500), a hook (600), a winch (800), and a magnetic powder brake (900). The recycling motor (300), power supply and controller (200) are all fixedly installed in the separate housing (100). The housing of the magnetic powder clutch (400) and the housing of the magnetic powder brake (900) are also fixedly installed in the separate housing (100). The input end of the magnetic powder clutch (400) is connected to the output shaft of the recycling motor (300), and the two ends of the transmission shaft (500) are respectively connected to the output end of the magnetic powder clutch (400) and the output end of the magnetic powder brake (900). The winch (800) is fixedly mounted on the drive shaft (500), the hook (600) is fixedly mounted on the detachable housing (100), and the detachable housing (100) has an opening located next to the winch (800); The two ends of the arresting cable (700) are respectively inserted into the two arresting devices through openings, and after being wound around the two winches (800) several times, they are fixedly connected to the hooks (600) in the two arresting devices. The recycling motor (300), magnetic powder clutch (400), drive shaft (500), winch (800) and magnetic powder brake (900) are coaxially arranged, and the drive shaft (500) serves as a key connecting shaft to sequentially connect the magnetic powder brake (900), winch (800) and magnetic powder clutch (400). The power supply and controller (200) is an integrated design and has a hollow cylindrical shape. The power supply and controller (200) has three sets of power transmission lines, which are connected to the recycling motor (300), the magnetic powder clutch (400) and the magnetic powder brake (900) respectively. The detachable shell (100) is a hollow cylinder, including a fixed surface (101) and a detachable surface (102). The fixed surface (101) includes a circular upper surface, a circular lower surface and a semi-cylindrical side surface, and has an opening for the arresting cable (700) to be led out. The detachable surface (102) is a semi-cylindrical shell. The fixed surface (101) and the detachable surface (102) are connected by bolts on the lugs. The bottom of the side surfaces of the fixed surface (101) and the detachable surface (102) have bolt holes for connecting to the ground.

2. The UAV arresting system based on magnetic particle brake according to claim 1, characterized in that, The drive shaft (500) is equipped with a speed sensor, and the magnetic powder brake (900) is equipped with a torque sensor. The speed signal and torque signal are collected respectively, and a signal cable is connected to the power supply and controller (200) as a feedback signal of the controller.

3. A control method for a UAV arresting system based on a magnetic particle brake according to claim 1, characterized in that, The operation of the drone interception system includes: Power is turned on and the controller (200) is connected. The ideal arresting torque curve is determined based on the UAV landing weight, arresting distance and maximum overload, and input into the controller. At this time, the power supply to the magnetic powder clutch (400) and the recovery motor (300) is disconnected, and the magnetic powder brake (900) is energized to prepare for arresting. After the UAV completes grounding and hooking, the magnetic powder brake (900) adjusts the UAV arresting torque in real time according to the input current of the pre-input ideal arresting torque curve. Throughout the entire arresting process, the controller adjusts the target's arresting torque in real time based on the difference between the current UAV speed and the ideal speed, thereby achieving closed-loop control of the arresting distance and UAV overload. After the arresting process is completed, the magnetic powder brake (900) is de-energized, while the magnetic powder clutch (400) and the recovery motor (300) are energized to achieve the recovery of the arresting cable. The controller is a PID-based outer loop controller for stopping and compensating force, and the magnetic powder brake (900) has a PID-based outer loop controller for stopping and compensating force. The inner loop controller for the resisting torque of the adaptive controller.

4. The control method for a UAV arresting system based on a magnetic particle brake according to claim 3, characterized in that, The input to the controller is the current winch rotation angle. Winch rotation angle in the ideal curve The difference; through control quantity To achieve compensation for the stopping torque: ;in , , These are proportional, integral, and differential gains, respectively.

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