Telescopic air injection device, active disturbance rejection control method and unmanned aerial vehicle

Abstract

The invention relates to the technical field of unmanned aerial vehicles, and discloses a telescopic air injection device, an active-disturbance-rejection control method and an unmanned aerial vehicle. A first air pipe is connected to a fuselage of the unmanned aerial vehicle through a gimbal frame mechanism; the second air pipe is coaxial with the first air pipe and is nested in the first air pipe; the third air pipe is coaxial with the second air pipe and is nested in the second air pipe; a rope, a first fixed pulley, a second fixed pulley, a third fixed pulley, a contraction driving winch and an extension driving winch; the contraction driving winch and the extension driving winch are connected to one end of the first air pipe, and the first fixed pulley is arranged at the other end of the first air pipe; the second fixed pulleys are arranged at two opposite ends of the second air pipe; the third fixed pulleys are arranged at two opposite ends of the third air pipe; the rope is sequentially wound around the first fixed pulley, the second fixed pulleys and the third fixed pulleys, the two ends of the rope are connected to the contraction driving winch and the extension driving winch correspondingly, and the controllable adjusting precision of the high-pressure airflow acting distance is improved.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) technology, and in particular to a retractable jet propulsion device, an active disturbance rejection control method, and an UAV. Background Technology

[0002] Existing drones, when utilizing high-pressure airflow for attitude-assisted control, environmental intervention, or jet operations, typically rely on a single-layer duct structure and a simple jet device with a fixed jet direction. During high-pressure airflow jetting, the jet flow is affected by the duct length, nozzle shape, and jet angle. These parameters are difficult to continuously, precisely, and in real-time controllable adjust during flight. Especially when dynamic control of the jet flow effect is required based on the mission scenario or external disturbances, existing solutions often only offer indirect compensation by altering the overall drone attitude or adjusting the airflow output power, as the airflow's effective distance cannot be changed. This results in slow airflow response, insufficient control precision, flight control risks, and significant energy consumption, reducing the drone's endurance. Summary of the Invention

[0003] This invention provides a retractable jet device, an active disturbance rejection control method, and an unmanned aerial vehicle (UAV), which solves the problem of insufficient controllable adjustment accuracy of airflow devices in the prior art.

[0004] To solve the above-mentioned technical problems, the present invention provides a retractable jet device, which includes a first air duct, the first air duct being connected to the fuselage of a drone via a universal joint mechanism; At least one second duct that is coaxial with the first duct and nested within the first duct; A third duct coaxial with and nested within the second duct; and At least one set of pulleys is connected to the universal joint mechanism. The pulley set includes a rope, a first fixed pulley, at least two second fixed pulleys and two third fixed pulleys, a retraction drive winch and an extension drive winch arranged coaxially. The retraction drive winch and the extension drive winch are located near one end of the first air duct, and the first fixed pulley is located at the other end of the first air duct. Each of the second fixed pulleys is located at opposite ends of the second air duct. The third fixed pulleys are located at opposite ends of the third air duct. The rope is sequentially wound around the first fixed pulley, each of the second fixed pulleys and each of the third fixed pulleys, and the two ends of the rope are respectively connected to the retraction drive winch and the extension drive winch.

[0005] In some embodiments, the device further includes a driver connected to the drone; both the retraction drive winch and the extension drive winch are connected to a shaft disposed on the driver.

[0006] In some embodiments, the diameter of the extension drive winch is larger than the diameter of the retraction drive winch.

[0007] In some embodiments, the gimbal mechanism includes a base, a tilt axis, and a pitch axis; one end of the base is connected to the fuselage of the UAV, one end of the pitch axis is connected to the other end of the base; the tilt axis is connected to the other end of the pitch axis; and the tilt axis is connected to the first air duct.

[0008] In some embodiments, a high-pressure air source mechanism is provided on the end face of the base facing away from the UAV; the air outlet of the high-pressure air source mechanism is aligned with the port of the third air duct.

[0009] In some embodiments, the gimbal mechanism further includes a dual-axis drive motor, which is communicatively connected to the control system of the UAV.

[0010] The present invention also provides an active disturbance rejection control method, applied to the retractable jet device in any of the foregoing embodiments, the method comprising: Based on the gimbal mechanism, a base coordinate system, a tilt axis coordinate system, and a pitch axis coordinate system are constructed respectively. Based on each coordinate system, the angular velocity and mapping relationship between adjacent coordinate systems, the inertia matrix of the pitch axis, and the inertia matrix of the tilt axis are derived. Based on the angular velocity and mapping relationship between the two adjacent coordinate systems, the inertia matrix of the pitch axis and the inertia matrix of the roll axis, the gimbal mechanism is modeled and analyzed using the Newton-Euler method based on the torque balance principle, resulting in a coupled dynamic model with pitch angular velocity and roll angular velocity as state variables. Based on the coupled dynamics model, pitch axis transfer function, roll axis transfer function, pitch axis direct disturbance transfer function and roll axis direct disturbance transfer function are established, and an inner loop controller is constructed based on each transfer function; Based on the inner loop controller, the preset first frequency weighting function and the preset second frequency weighting function, a hybrid sensitivity optimization objective function is constructed, and the outer loop robust controller is obtained by solving the hybrid sensitivity optimization objective function; Based on the balance reduction of Hankel singular values, the outer-loop robust controller is reduced in order to obtain a low-order outer-loop robust controller. Based on the inner loop controller and the outer loop low-order robust controller, active disturbance rejection control commands are generated.

[0011] In some embodiments, the step of establishing pitch axis transfer functions, roll axis transfer functions, pitch axis direct disturbance transfer functions, and roll axis direct disturbance transfer functions based on the coupled dynamics model, and constructing an inner-loop controller based on each transfer function, includes: Based on the coupled dynamics model, the pitch axis channel and roll axis channel of the universal joint mechanism are linearized by small disturbances to obtain the pitch axis transfer function, the roll axis transfer function, and the direct disturbance transfer function of the pitch axis external disturbance acting on the pitch axis and the direct disturbance transfer function of the roll axis external disturbance acting on the roll axis. Based on the pitch axis transfer function, the roll axis transfer function, the direct disturbance transfer function of the pitch axis, and the direct disturbance transfer function of the roll axis, pitch axis inner loop controllers and roll axis inner loop controllers for disturbance compensation are constructed respectively, wherein: The pitch axis inner loop controller is obtained by inverting the pitch axis transfer function and multiplying the inverted result by the direct disturbance transfer function of the pitch axis. The inner loop controller of the roll axis is obtained by inverting the roll axis transfer function and multiplying the inverted result by the direct disturbance transfer function of the roll axis.

[0012] In some embodiments, the step of constructing a hybrid sensitivity optimization objective function based on the inner-loop controller, a preset first frequency weighting function, and a preset second frequency weighting function, and solving the hybrid sensitivity optimization objective function to obtain the outer-loop robust controller, includes: Based on the inner loop controller, the pitch axis channel and tilt axis channel of the universal joint mechanism are constructed into a controlled object transfer matrix with a dual-input dual-output structure; Based on the controlled object transfer matrix, a sensitivity function and a complementary sensitivity function are constructed. Based on the first frequency weighting function, the sensitivity function is weighted to obtain the weighted sensitivity function; Based on the second frequency weighting function, the complementary sensitivity function is weighted to obtain the weighted complementary sensitivity function. Based on the weighted sensitivity function and the weighted complementary sensitivity function, the hybrid sensitivity optimization objective function is constructed. The objective function for optimizing the hybrid sensitivity is minimized, and the outer-loop robust controller is constructed based on the set of control parameters obtained from the solution.

[0013] The present invention also provides an unmanned aerial vehicle (UAV) applied to the retractable jet device in any of the foregoing embodiments, which further includes an active disturbance rejection control system, the active disturbance rejection control system including a processor for executing an inner-loop controller and an outer-loop robust controller in the active disturbance rejection control method of any of the foregoing embodiments.

[0014] Compared with the prior art, the retractable jet device of this invention has the following advantages: In this embodiment of the invention, the first duct is connected to the fuselage of the UAV via a universal joint mechanism. A second duct is coaxially nested within the first duct, and a third duct is coaxially nested within the second duct, forming a multi-stage duct structure. Simultaneously, at least one set of pulleys is provided at the universal joint mechanism. Each pulley set includes a rope, a first fixed pulley, multiple second fixed pulleys, and multiple third fixed pulleys, as well as a retraction drive winch and an extension drive winch respectively connected to both ends of the rope. The retraction drive winch and the extension drive winch are connected to one end of the first duct, and the first fixed pulley is located at the other end of the first duct. The second fixed pulleys are located at opposite ends of the second duct, and the third fixed pulleys are located at opposite ends of the third duct. The rope is sequentially wound around the first fixed pulley, each of the second fixed pulleys, and each of the third fixed pulleys, so that the rotation of the retraction drive winch or the extension drive winch can generate synchronous axial traction or relaxation of the multi-stage duct structure (first duct, each of the second ducts, and each of the third ducts) through the rope. Through the traction transmission relationship of the aforementioned multi-stage pulleys, the outermost first duct, the middle second duct, and the innermost third duct can achieve coordinated telescopic movements in the coaxial direction, thereby enabling the multi-stage duct structure to form a continuously adjustable airflow jet length. Specifically, when the retraction drive winch tightens the drive rope, each stage of the duct is pulled closer together, and the airflow jet distance shortens accordingly; conversely, when the extension drive winch loosens the drive rope, each stage of the duct extends sequentially along the axial direction, and the airflow jet distance increases accordingly. By utilizing the coordinated traction relationship between the multi-stage nested ducts and the corresponding pulley groups, this embodiment of the invention no longer relies on the fixed geometric dimensions of a single-stage duct to adjust the airflow action distance, but achieves high-resolution continuous telescopic adjustment through mechanical transmission. Thus, this embodiment of the invention achieves precise and controllable adjustment of the high-pressure airflow action distance through the linkage telescopic structure of the winch-pulley-multi-stage duct structure. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the retractable jet device provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the retractable jet device provided in an embodiment of the present invention in an extended state; Figure 3 This is a schematic diagram of the retractable jet device provided in an embodiment of the present invention in a retracted state; Figure 4 This is a flowchart illustrating the active disturbance rejection control method provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the active disturbance rejection control system provided in an embodiment of the present invention.

[0016] In the diagram, 100 is the first duct; 200 is the second duct; 300 is the third duct; 400 is the pulley block; 410 is the rope; 420 is the first fixed pulley; 430 is the second fixed pulley; 440 is the third fixed pulley; 450 is the retraction drive winch; and 460 is the extension drive winch. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. 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 are within the scope of protection of the present invention.

[0018] In the description of this invention, it should be noted that the directional terms such as "center", "upper", "lower", "inner", and "outer" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this invention.

[0019] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. Thus, the use of "first" and "second" to define a feature may explicitly or implicitly include one or more of that feature, and in the description of this invention, "at least" means one or more, unless otherwise explicitly specified.

[0020] In this invention, unless otherwise explicitly specified and limited, the terms "assembly," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can also refer to a mechanical connection; they can refer to a direct connection or a connection through an intermediate medium; or they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0021] See again Figures 1 to 3This invention provides a retractable jet device, comprising a first air duct 100 connected to the fuselage of a drone via a universal joint mechanism; at least one second air duct 200 coaxial with and nested within the first air duct 100; a third air duct 300 coaxial with and nested within the second air duct 200; and at least one set of pulley blocks 400 connected to the universal joint mechanism. The pulley blocks 400 include a rope 410, a first fixed pulley 420, at least two second fixed pulleys 430 and two third fixed pulleys 440, a retraction drive winch 450 coaxially arranged, and an extension drive winch. A movable winch 460; the retraction drive winch 450 and the extension drive winch 460 are located near one end of the first air duct 100, and the first fixed pulley 420 is located at the other end of the first air duct 100; each of the second fixed pulleys 430 is located at opposite ends of the second air duct 200; the third fixed pulley 440 is located at opposite ends of the third air duct 300; the rope 410 is sequentially wound around the first fixed pulley 420, each of the second fixed pulleys 430 and each of the third fixed pulleys 440, and the two ends of the rope 410 are respectively connected to the retraction drive winch 450 and the extension drive winch 460.

[0022] In this embodiment, the UAV fuselage, gimbal mechanism, and duct assembly (i.e., the assembly consisting of a first duct 100, at least one second duct 200, and a third duct 300) are rigidly connected in a "UAV fuselage—dual-axis gimbal mechanism—duct assembly" manner. The UAV fuselage has a standardized mounting interface on a pre-defined mounting area. The base of the dual-axis gimbal mechanism is fixedly connected to this interface with high-strength bolts, and a rubber buffer pad is placed at the connection to absorb some vibration from the duct assembly. The output end (i.e., the tilt axis) of the dual-axis gimbal mechanism is connected to the first duct 100, and its coaxiality with the rotation axis of the gimbal mechanism is maintained by a locating pin. This achieves stable support of the UAV fuselage for the gimbal mechanism, precise attitude adjustment of the duct assembly by the gimbal mechanism, and controllable orientation of the duct assembly relative to the UAV fuselage.

[0023] Specifically, the duct assembly of the retractable jet device extends horizontally along the outer side of the UAV fuselage (or can be adjusted to extend at an angle according to operational requirements), thus not obstructing the lift area of ​​the UAV propeller. The gimbal mechanism is installed in the mounting area in the middle of the UAV fuselage (avoiding core components such as batteries and flight controllers), and the duct assembly of the retractable jet device is located below or to the side of the UAV fuselage. The first duct 100 faces the target operational direction, and the overall center of gravity of the first duct 100 and the gimbal mechanism is on the same vertical line as the center of gravity of the UAV fuselage to ensure the flight stability of the UAV.

[0024] More specifically, the first duct 100 is the outermost load-bearing duct, which can be made of high-strength, lightweight materials, such as carbon fiber reinforced resin or aluminum alloy, to balance structural rigidity and load-bearing capacity. The first duct 100 is mounted to the fuselage of the UAV via a gimbal mechanism. Since the gimbal mechanism contains interconnected tilt and pitch axes, and the first duct 100 is connected to the end of the pitch axis, it allows for small-angle rotational adjustments in both the pitch and tilt directions. This, combined with the UAV's attitude control, provides greater controllability to the direction of the high-pressure airflow. Thus, the first duct 100, through the gimbal mechanism, can achieve multi-degree-of-freedom directional control, reducing the coupling between the high-pressure airflow direction and the UAV's attitude, thereby improving jet stability and positioning accuracy.

[0025] In this embodiment, the second duct 200 and the first duct 100 are coaxially arranged and nested. The outer diameter of the second duct 200 is slightly smaller than the inner diameter of the first duct 100, thus forming a sliding fit. Second fixed pulleys 430 are respectively provided at opposite ends of the second duct 200. The second duct 200 is connected to a rope 410 via the second fixed pulleys 430. The two ends of the rope 410 are respectively connected to a contraction drive winch 450 and an extension drive winch 460. The rotation of the contraction drive winch 450 and the extension drive winch 460 drives the rope 410 to contract, allowing the second duct 200 to extend or retract relative to the first duct 100 in the axial direction when the rope 410 contracts.

[0026] Specifically, the second duct 200 can be made of high-temperature resistant, lightweight materials to reduce the impact on the drone's endurance. In this way, by setting up a retractable second duct 200, the jet distance can be continuously adjusted without changing the installation position of the first duct 100, significantly improving the flexibility of adjusting the high-pressure airflow's effective distance.

[0027] More specifically, the number of second ducts 200 is at least one, meaning that two, three, or more second ducts 200 can be set according to the actual needs of high-pressure airflow operations. It should be noted that when multiple second ducts 200 are set, the outer diameter of each second duct 200 increases sequentially from the inside to the outside, so that the second ducts 200 can be coaxially nested in a diameter-step relationship, thereby forming a multi-stage expandable duct structure to further expand the adjustable stroke of the high-pressure airflow channel.

[0028] In this embodiment, the third duct 300 is coaxially arranged with the second duct 200 and is the innermost retractable duct structure. The third duct 300 is also linked to the winches (retraction drive winch 450 and extension drive winch 460) via the third fixed pulley 440 in the pulley block 400. The third fixed pulleys 440 are located at opposite ends of the third duct 300, allowing the third duct 300 to extend and retract further under the influence of the second duct 200 and the rope 410.

[0029] Specifically, to reduce jet loss, the inner wall of the third duct 300 can be coated with a low-friction coating (such as polytetrafluoroethylene coating) to improve airflow efficiency. This allows for fine-tuning of the axial position via the third duct 300, enabling the effective jet length of the entire duct to be adjusted at a higher resolution, thereby further improving the precision of jet distance control.

[0030] Specifically, the length ratio of the first duct 100, the second duct 200, and the third duct 300 can be 1:1:1. This equal-length structural design helps maintain a stable center of gravity distribution during expansion and contraction, reduces vibration during expansion and contraction, and improves the smoothness and accuracy of adjusting the airflow direction and effective distance.

[0031] Understandably, the first duct 100 has the largest diameter, the second duct 200 has the second largest diameter, and the third duct 300 has the smallest diameter, so that the third duct 300 can be fitted inside the second duct 200, and the second duct 200 can be fitted inside the first duct 100.

[0032] More specifically, the ratio of the number of second fixed pulleys 430 to the number of second air ducts 200 is 2:1, so that a sufficient number of second fixed pulleys 430 can be set at opposite ends of the second air ducts 200.

[0033] In this embodiment, the pulley system connected to the base of the gimbal mechanism can be configured as two sets. Each pulley system 400 includes a rope 410, a first fixed pulley 420, at least two second fixed pulleys 430 and two third fixed pulleys 440, a retraction drive winch 450 and an extension drive winch 460 arranged coaxially. The retraction drive winch 450 and the extension drive winch 460 are connected to the base of the gimbal mechanism and are located on the end face of the base facing away from the UAV fuselage. Furthermore, the connection relationships between the rope 410, each fixed pulley, and each air duct have been discussed in the previous embodiments and will not be repeated here.

[0034] In one embodiment, a driver connected to the drone is also included; both the retraction drive winch 450 and the extension drive winch 460 are connected to a shaft provided on the driver (not shown in the figure).

[0035] In this embodiment, the output shaft of the driver passes through both the retraction drive winch 450 and the extension drive winch 460, and is connected to the central shaft holes of both. Therefore, when the driver drives in the forward direction, it can drive the extension drive winch 460 to rotate synchronously to extend the rope; when the driver drives in the reverse direction, it can drive the retraction drive winch 450 to rotate to retract the rope. By allowing the two winches to share the same shaft, the number of transmission structures can be reduced, the accumulated backlash caused by multi-stage transmission can be avoided, and the synchronization and response speed of the rope extension and retraction processes can be improved.

[0036] In one embodiment, such as Figure 1 , Figure 2 as well as Figure 3 As shown, the diameter of the extension drive winch 460 is larger than the diameter of the retraction drive winch 450.

[0037] In this embodiment, the extension drive winch 460 and the retraction drive winch 450 are coaxially arranged at one end of the first duct 100, and the effective winding diameter of the extension drive winch 460 is preferably 1.2-2 times the diameter of the retraction drive winch 450. Specifically, if the end of the first duct 100 with the first fixed pulley 420 is designated as the first end, and the port opposite the first end is designated as the second end, then the extension drive winch 460 and the retraction drive winch 450 are coaxially arranged in the region near the second end.

[0038] By increasing the diameter of the extension drive winch 460, the unit angular displacement of the rope 410 during the duct extension stage corresponds to a larger linear winding length, thereby improving the adjustment resolution and control stability during the duct extension process. Simultaneously, the smaller diameter retraction drive winch 450 provides higher force transmission efficiency during the retraction stage, ensuring greater stability of the multi-stage nested duct's posture during retrieval. This achieves high-precision adjustment of the multi-stage duct's extension and retraction stroke, further enhancing the controllability of the high-pressure airflow's effective distance.

[0039] In one embodiment, the gimbal mechanism includes a base (not shown in the figure), a tilt axis (not shown in the figure), and a pitch axis (not shown in the figure); one end face of the base is connected to the fuselage of the UAV, one end of the pitch axis is connected to the other end face of the base; the tilt axis is connected to the other end of the pitch axis; and the tilt axis is connected to the first air duct 100.

[0040] In this embodiment, the gimbal mechanism adopts a two-stage rotational structure. Specifically, the base of the gimbal mechanism is connected to the fuselage of the UAV via threaded fasteners or quick-release clips, ensuring stable support under flight vibration conditions. The pitch axis is rotatably mounted to the base via a pin and is equipped with a low-friction bushing to reduce rotational resistance, thereby allowing the first duct 100 to achieve rapid small-angle adjustments in the pitch direction. The tilt axis is mounted at the distal end of the pitch axis, with its axial direction perpendicular to the pitch axis, and is supported by double-sided bearings to improve rotational stiffness in the tilt direction. The sidewall of the first duct 100 is connected to the output / end of the tilt axis, enabling the first duct 100 to achieve independent follow-up rotation in the tilt direction. Through the above structural arrangement, the first duct 100 can achieve attitude adjustment in both pitch and tilt degrees of freedom, thereby improving the accuracy of airflow direction control.

[0041] Specifically, the above configuration allows the pitch axis (Z-axis) and roll axis (V-axis) of the gimbal mechanism to rotate independently, thereby enabling the retractable jet device to achieve ±30° pitch adjustment and ±20° roll adjustment. Thus, during operation, the attitude of the gimbal mechanism can be controlled by the flight control system to counteract the disturbances caused by the airflow reaction force, ensuring that the high-pressure airflow is precisely directed towards the target area.

[0042] In one embodiment, a high-pressure air source mechanism (not shown in the figure) is provided on the end face of the base facing away from the UAV; the air outlet of the high-pressure air source mechanism is aligned with the port of the third air duct 300.

[0043] In this embodiment, a high-pressure air source mechanism is fixedly installed on the side of the base away from the UAV fuselage. This high-pressure air source mechanism is connected to the power supply system of the UAV body through a conduit and an electrical control interface to achieve a stable high-pressure air supply. The air outlet of the high-pressure air source mechanism is arranged along the axial direction of the base, and its jet direction points towards the port of the third air duct 300, thereby ensuring that the high-pressure airflow can directly enter the interior of the third air duct 300 after jetting. By arranging the high-pressure air source mechanism on the end face of the base away from the UAV, not only is interference from the high-pressure airflow to the UAV body avoided, but the risk of attitude deviation caused by flow field disturbance is also reduced. At the same time, the high-pressure airflow is transmitted along the coaxial direction of each air duct, which helps to improve the stability and guiding efficiency of the overall airflow channel.

[0044] Specifically, the high-pressure air source mechanism can be an industrial multi-stage axial flow fan.

[0045] In one embodiment, the gimbal mechanism further includes a dual-axis drive motor (not shown in the figure), which is communicatively connected to the control system of the UAV.

[0046] In this embodiment, a dual-axis drive motor is connected to the tilt and pitch axes to drive their rotation. The dual-axis drive motor is communicatively connected to the UAV's control system, which receives real-time operating status signals (such as jet pressure and duct extension length) from the retractable jet system and dynamically adjusts the tilt and pitch axes based on these signals.

[0047] Specifically, the operating principle of the UAV's control system for controlling the attitude of the gimbal mechanism, the extension and retraction of each air duct, and the operation of the high-pressure air source mechanism is as follows: The UAV's control system acquires the UAV's spatial attitude information and the location of the target point in real time. According to the operational requirements, it sends pitch and roll angle adjustment commands to the dual-axis drive motors in the universal joint mechanism, so that the pitch and roll axes drive the first air duct 100 to complete a precise two-degree-of-freedom rotation in space, thereby ensuring that the air outlet of the first air duct 100 always points towards the target area. Simultaneously, the control system outputs synchronous or reverse speed control commands to the drivers of the retraction drive winch 450 and the extension drive winch 460 according to the required high-pressure airflow distance. When extension is required, the extension drive winch 460 accelerates the winding of the rope 410 and drives the rope 410 to pull the fixed pulleys of the first air duct 100, the second air duct 200 and the third air duct 300 in sequence, so that the second air duct 200 extends smoothly relative to the first air duct 100 and the third air duct 300 continues to extend relative to the second air duct 200. When retraction is required, the control system commands the retraction drive winch 450 to generate a larger recovery torque, pulling the rope 410 in the opposite direction along the path of the multi-stage fixed pulleys, so that the third air duct 300 is gradually recovered into the second air duct 200 and further recovered into the first air duct 100, thereby realizing controllable multi-stage extension and retraction adjustment. Simultaneously, the control system sends start / stop and output intensity control commands to the high-pressure air source mechanism according to the operational intensity requirements. This allows the high-pressure air source mechanism to continuously inject high-pressure airflow into the first duct 100 when needed. The airflow is guided along the multi-stage coaxially nested duct to the port of the first duct 100 and sprayed to the target location. Through the coordinated operation of these three components, the control system achieves comprehensive control of the spray direction, spray distance, and spray intensity, thereby ensuring that the high-pressure airflow maintains stable, accurate, and adjustable operational performance under different operational scenarios.

[0048] like Figure 4 As shown, the present invention also provides an active disturbance rejection control method, applied to the retractable jet device in any of the foregoing embodiments, the method comprising: S1. Based on the gimbal mechanism, construct the base coordinate system, the tilt axis coordinate system, and the pitch axis coordinate system respectively. Based on each coordinate system, derive the angular velocity and mapping relationship between adjacent coordinate systems, the inertia matrix of the pitch axis, and the inertia matrix of the tilt axis. S2. Based on the angular velocity and mapping relationship between the two adjacent coordinate systems, the inertia matrix of the pitch axis and the inertia matrix of the roll axis, the gimbal mechanism is modeled and analyzed using the Newton-Euler method based on the torque balance principle to obtain a coupled dynamic model with pitch angular velocity and roll angular velocity as state variables. S3. Based on the coupled dynamics model, establish the pitch axis transfer function, roll axis transfer function, pitch axis direct disturbance transfer function, and roll axis direct disturbance transfer function, and construct an inner loop controller based on each transfer function; S4. Based on the inner loop controller, the preset first frequency weighting function and the preset second frequency weighting function, construct a hybrid sensitivity optimization objective function, and solve the hybrid sensitivity optimization objective function to obtain the outer loop robust controller; S5. Based on the balance reduction of Hankel singular values, the outer-loop robust controller is reduced in order to obtain a low-order outer-loop robust controller. S6. Based on the inner loop controller and the outer loop low-order robust controller, generate active disturbance rejection control commands.

[0049] In this embodiment, prior to step S1, the gimbal mechanism in the retractable jet device can be adjusted based on the dynamic and aerodynamic characteristics of the retractable jet device and the dynamic characteristics of the UAV, resulting in an adjusted gimbal mechanism. Subsequent step S1 processes the system based on this adjusted gimbal mechanism.

[0050] Specifically, firstly, based on the dynamic and aerodynamic characteristics of the retractable jet device and the overall dynamic characteristics of the UAV, a joint model of the gimbal mechanism inside the jet device is performed. By analyzing the thrust direction change caused by nozzle extension and retraction, the torque deviation caused by jet adhesion effect, and the coupled disturbances of the UAV body under different attitudes, the equivalent inertial parameters and damping parameters of each degree of freedom of the gimbal are determined. Then, based on these parameters, the frequency response identification of the servo links of the pitch and roll axes of the gimbal mechanism is performed, obtaining their characteristic frequencies and gain variation laws under different nozzle extension and retraction amounts. Through model correction and parameter tuning, the servo dynamic response of the gimbal is made consistent with the thrust generation characteristics of the retractable jet device, thereby completing the calibration of the gimbal mechanism and obtaining the calibrated gimbal mechanism. In the subsequent step S1, the control system uses the calibrated gimbal mechanism as a basis to further construct the attitude mapping relationship and disturbance estimation model of the jet channel, so that the subsequent controller design can accurately reflect the dynamic effects brought about by the nozzle extension and retraction changes.

[0051] In this embodiment, a base coordinate system fixed to the base is established. Establish a pitch axis coordinate system fixed to the pitch axis. Establish a roll axis coordinate system fixed to the roll axis. Pitch axis coordinate system Around the axis Rotation angle After and base coordinate system Coincident, tilt axis coordinate system Around the axis Rotation angle Back and pitch axis coordinate system Coincident, pitch axis coordinate system To the base coordinate system and the tilt axis coordinate system To the pitch axis coordinate system Transformation matrix and as follows: angular velocity between two adjacent coordinate systems , and The mapping relationship is calculated as follows: ; ; , , ; In the formula, The base angular velocity vector, Each component in the coordinate system corresponds to the i-axis, j-axis, and k-axis of the base coordinate system. The pitch axis angular velocity vector, Each component corresponds to the x-axis, y-axis, and z-axis of the pitch coordinate system; The angular velocity vector of the roll axis. Each component corresponds to the u-axis, v-axis, and w-axis of the tilt coordinate system.

[0052] Inertia matrices of pitch and roll axes and These can be represented as follows: In the formula, the inertia matrix J for the pitch axis M Its diagonal elements represent the moment of inertia, and its off-diagonal elements represent the product of inertia; specifically, M x M is the moment of inertia of the pitch axis about the x-axis of the pitch axis coordinate system; y M is the moment of inertia of the pitch axis about the y-axis of the pitch axis coordinate system; z M is the moment of inertia of the pitch axis about the z-axis of the pitch axis coordinate system; xy M is the product of inertia about the plane containing the x and y axes; xz M is the product of inertia about the plane containing the x and z axes;yz Let J be the product of inertia about the plane containing the y and z axes. The inertia matrix J for the roll axis is... N Its diagonal elements represent the moment of inertia, and its off-diagonal elements represent the product of inertia; specifically, N u N is the moment of inertia of the roll axis about the u-axis of the roll axis coordinate system; v N represents the moment of inertia of the roll axis about the v-axis of the roll axis coordinate system. w N represents the moment of inertia of the roll axis about the w-axis of the roll axis coordinate system. uv N is the product of inertia about the plane containing the u-axis and v-axis; uw N is the product of inertia about the plane containing the u-axis and w-axis; vw Let be the product of inertia about the plane containing the v-axis and w-axis.

[0053] The gimbal mechanism is analyzed using the Newton-Euler method based on the torque balance principle. The dynamic relationship between the external torque applied to the mechanism and the mechanism's motion is as follows: ; In the formula, Represents angular momentum. Indicates external torque. Indicates angular velocity. The moment of inertia of the coordinate axes is represented; the dynamic equation for the roll axis is calculated as follows: ; In the formula, To be applied to the roll shaft Total external torque of the shaft; N represents the inertial disturbance caused by the rotation of the base; v Let v be the moment of inertia of the roll axis about the v-axis; ω is the angular acceleration of the roll axis about the v-axis; This represents the cross-coupling disturbance caused by the mutual movement between the base and the universal joint; these disturbances can be represented as follows: ; ; Similarly, the dynamic model of the pitch axis is derived as follows: ; ; In the formula, J x The effective moment of inertia of the pitch axis; Angular acceleration of the pitch axis; To be applied to the pitch axis Total external torque of the shaft; The inertial disturbance is caused by the rotation of the base. These are cross-coupled disturbances caused by the mutual motion between the pitch and roll gimbals; these disturbances can be represented as follows: ; ; Substituting the above equation into the dynamic model, we can obtain the coordinate system. The differential equation / dynamic model for pitch angular velocity is as follows: .

[0054] In this embodiment, the attitude angular velocity feedback value is received in real time. The total disturbance caused by high-speed jet disturbance and ambient airflow is estimated through an extended state observer. Based on the estimated disturbance, the angular velocity control law is feedforward compensated to obtain the inner loop disturbance compensation control law, which enables the angular velocity to return to the desired trajectory within a millisecond timescale. Simultaneously, the desired angular velocity is generated based on the attitude angular error and thrust bias model. A low-order robust structure is used to suppress parameter perturbations caused by nozzle extension and retraction, ensuring that the desired angular velocity trajectory remains smooth and reliable. In each control cycle, the desired angular velocity output from the outer loop is combined with the disturbance compensation control law from the inner loop to obtain the final active disturbance rejection control command. The attitude of the gimbal mechanism is adjusted according to the active disturbance rejection control command to achieve high-precision attitude stabilization and rapid response of the UAV.

[0055] In one embodiment, the step of establishing pitch axis transfer functions, roll axis transfer functions, pitch axis direct disturbance transfer functions, and roll axis direct disturbance transfer functions based on the coupled dynamics model, and constructing an inner-loop controller based on each transfer function, includes: Based on the coupled dynamics model, the pitch axis channel and roll axis channel of the universal joint mechanism are linearized by small disturbances to obtain the pitch axis transfer function, the roll axis transfer function, and the direct disturbance transfer function of the pitch axis external disturbance acting on the pitch axis and the direct disturbance transfer function of the roll axis external disturbance acting on the roll axis. Based on the pitch axis transfer function, the roll axis transfer function, the direct disturbance transfer function of the pitch axis, and the direct disturbance transfer function of the roll axis, pitch axis inner loop controllers and roll axis inner loop controllers for disturbance compensation are constructed respectively, wherein: The pitch axis inner loop controller is obtained by inverting the pitch axis transfer function and multiplying the inverted result by the direct disturbance transfer function of the pitch axis. The inner loop controller of the roll axis is obtained by inverting the roll axis transfer function and multiplying the inverted result by the direct disturbance transfer function of the roll axis.

[0056] In this embodiment, the transfer function and corresponding mutual perturbation of each component of the gimbal system are described as follows: This represents the pitch axis transfer function of the gimbal. Represents the transfer function of the tilt axis of the universal joint. The direct disturbance transfer function representing the pitch axis of the gimbal. The direct disturbance transfer function representing the tilt axis of the gimbal is expressed by the inner loop controller as follows: ; ; In the formula, The inner loop controller represents the pitch axis; The inner loop controller represents the roll axis.

[0057] In one embodiment, the step of constructing a hybrid sensitivity optimization objective function based on the inner-loop controller, a preset first frequency weighting function, and a preset second frequency weighting function, and solving the hybrid sensitivity optimization objective function to obtain the outer-loop robust controller, includes: Based on the inner loop controller, the pitch axis channel and tilt axis channel of the universal joint mechanism are constructed into a controlled object transfer matrix with a dual-input dual-output structure; Based on the controlled object transfer matrix, a sensitivity function and a complementary sensitivity function are constructed. Based on the first frequency weighting function, the sensitivity function is weighted to obtain the weighted sensitivity function; Based on the second frequency weighting function, the complementary sensitivity function is weighted to obtain the weighted complementary sensitivity function. Based on the weighted sensitivity function and the weighted complementary sensitivity function, the hybrid sensitivity optimization objective function is constructed. The objective function for optimizing the hybrid sensitivity is minimized, and the outer-loop robust controller is constructed based on the set of control parameters obtained from the solution.

[0058] In this embodiment, a hybrid sensitivity is used. Controller replaces classic Controller Represents the system transfer matrix. Represents the controller transfer matrix and sensitivity function. and complementary sensitivity function The statement is as follows: ; ; In the formula, GK represents the system transfer matrix. Transfer matrix with controller The product of matrices; I is the identity matrix.

[0059] H ∞The norm optimization objective function / mixed sensitivity optimization objective function is expressed as follows: .

[0060] In the formula, For indexing, specifically representing the pitch axis and roll axis , and This represents the frequency-dependent weighting function (i.e., the first frequency weighting function and the second frequency weighting function) that depends on the interference characteristics; G i This represents the transfer function of the controlled object, corresponding to channel i, for example, G. x It is the dynamic model of the pitch axis; K i This represents the transfer function of the controller to be designed, corresponding to channel i; Let be the closed-loop transfer function matrix from external input W (such as disturbance or noise) to performance output Z (such as tracking error or control energy), where the superscript i denotes the control channel. The system and disturbance transfer functions are calculated based on system parameters, substituted into the problem, and iterated multiple times. Using Hankel singular value-based equilibrium reduction, the transfer function of the outer-loop low-order robust controller can finally be obtained.

[0061] like Figure 5 As shown, the present invention also provides a drone, applied to the retractable jet device in any of the foregoing embodiments, and further includes an active disturbance rejection control system, the active disturbance rejection control system including a processor for executing an inner loop controller and an outer loop robust controller as in any of the foregoing active disturbance rejection control methods.

[0062] In this embodiment, the entire active disturbance rejection control system consists of two main parts: the main feedback control loop and the feedforward decoupling compensation network. First, the main feedback control loop. The two main paths in the diagram represent two control channels (e.g., the x-channel represents the pitch axis, and the y-channel represents the roll axis). Controller K x (s) and K y (s) are the main feedback controllers for their respective channels (e.g., H) ∞ (etc.). Their core function is to track instructions and eliminate errors. The controller will receive the expected instruction (x... d , y d ) and the actual output of the system The comparison is performed to generate an error signal, and the main control quantity u is calculated based on this error. x and u y This drives the controlled object. The controlled object G x (s) and G y(s) represents the physical and dynamic characteristics of the two channels themselves. This main feedback loop ensures the basic stability of the system and its ability to suppress unknown external disturbances.

[0063] First, the feedforward decoupling compensation network. This is the essence of the control architecture; its purpose is to actively cancel the cross-coupling disturbances between the two channels. In a physical gimbal system, when the pitch axis (x-axis) moves, an unwanted disturbance torque is generated on the roll axis (y-axis) due to gyroscopic effects, and vice versa. The role of the feedforward decoupling network is to cancel out this disturbance before it actually has an effect. Coupled Channel Model Ĝ x (s) and Ĝ y (s): These two modules are key to the entire decoupling design. They are not physical entities, but rather mathematical models of the system's cross-coupling characteristics. Ĝ y (s) The model describes: when the x channel produces output How much interference will this cause to the y-channel? x The (s) model describes: when the y channel generates output How much interference will it cause to the x channel?

[0064] Specifically, the decoupling principle is as follows: For the x channel: the system monitors the output of the y channel in real time. This signal is fed into the coupled model. x (s), the model will calculate The expected interference amount that will soon affect the x-channel. This expected interference amount serves as a feedforward compensation signal, and is related to the main controller K. x (s) Output main control quantity u x Add them together to form the final total control quantity û x Ideally, the compensation signal should be exactly equal in magnitude and opposite in direction to the actual coupling disturbance, thus completely canceling it out.

[0065] For the y-channel: Similarly, the system monitors the output of the x-channel. Through Ĝ y (s) The model calculates the expected interference to the y-channel and compares it with the main control quantity u. y Superimposed to form the total control quantity û y This is to counteract coupling interference from the x channel.

[0066] Thus, through this strategy combining feedback control and feedforward compensation, the system controller no longer passively waits for errors to occur before correcting them, but actively and proactively eliminates internal coupling disturbances. This transforms the two previously intertwined control channels into two independent, easily controllable single-channel systems from the controller's perspective. The ultimate effect is that when a command requires one axis to move, the other axis can remain stable, greatly improving the system's control accuracy, response speed, and dynamic performance.

[0067] The working process of this invention is as follows: A first duct is connected to the fuselage of a drone via a universal joint mechanism. A second duct is coaxially nested within the first duct, and a third duct is coaxially nested within the second duct, forming a multi-stage duct structure. Simultaneously, at least one set of pulleys is provided at the universal joint mechanism. Each pulley set includes a rope, a first fixed pulley, multiple second fixed pulleys, and multiple third fixed pulleys, as well as a retraction drive winch and an extension drive winch respectively connected to both ends of the rope. The retraction drive winch and the extension drive winch are connected to one end of the first duct, and the first fixed pulley is located at the other end of the first duct. Each second fixed pulley is located at opposite ends of the second duct; each third fixed pulley is located at opposite ends of the third duct. The rope is sequentially wound around the first fixed pulley, each second fixed pulley, and each third fixed pulley, so that the rotation of the retraction drive winch or the extension drive winch can generate synchronous axial traction or relaxation of the multi-stage duct structure (first duct, each second duct, and each third duct) through the rope. Through the traction transmission relationship of the aforementioned multi-stage pulleys, the outer first duct, the middle second duct, and the inner third duct can achieve coordinated telescopic movements in the coaxial direction, thereby enabling the multi-stage duct structure to form a continuously adjustable airflow jet length. Specifically, when the contraction drive winch tightens the drive rope, each stage of the duct is pulled closer together, and the airflow jet distance shortens accordingly; conversely, when the extension drive winch loosens the drive rope, each stage of the duct extends sequentially along the axial direction, and the airflow jet distance increases accordingly. By utilizing the coordinated traction relationship between the multi-stage nested ducts and the corresponding pulley groups, this embodiment of the invention no longer relies on the fixed geometric dimensions of a single-stage duct to adjust the airflow distance, but achieves high-resolution continuous telescopic adjustment through mechanical transmission. Thus, this embodiment of the invention achieves precise and controllable adjustment of the high-pressure airflow distance through the linkage telescopic structure of the winch-pulley-multi-stage duct structure. Its structure is compact and responsive, significantly improving the accuracy of the controllable adjustment of the high-pressure airflow distance.

[0068] In summary, the embodiments of the present invention provide a retractable jet device, an active disturbance rejection control method, and a drone, comprising a first air duct connected to the fuselage of the drone via a universal joint mechanism; at least one second air duct coaxial with and nested within the first air duct; a third air duct coaxial with and nested within the second air duct; and at least one set of pulleys connected to the universal joint mechanism. The pulley set includes a rope, a first fixed pulley, at least two second fixed pulleys and two third fixed pulleys, a retraction drive winch and an extension drive winch coaxially arranged; the retraction drive winch and the extension drive winch are located near one end of the first air duct, and the first fixed pulley is located at the other end of the first air duct; each of the second fixed pulleys is located at opposite ends of the second air duct; the third fixed pulleys are located at opposite ends of the third air duct; the rope is sequentially wound around the first fixed pulley, each of the second fixed pulleys, and each of the third fixed pulleys, and both ends of the rope are respectively connected to the retraction drive winch and the extension drive winch. The embodiments of the present invention improve the accuracy of controllable adjustment of the high-pressure airflow action distance.

[0069] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A retractable jet device, characterized in that, Comprise: A first air duct connected to the body of the unmanned aerial vehicle through a gimbal mechanism; At least one second air duct coaxial with the first air duct and nested in the first air duct; A third air duct coaxial with the second air duct and nested in the second air duct; and At least one pulley block connected to the gimbal mechanism, the pulley block comprising a rope, a first fixed pulley, at least two second fixed pulleys and two third fixed pulleys, a contraction drive winch and an expansion drive winch arranged coaxially; The contraction drive winch and the expansion drive winch are close to one end of the first air duct, and the first fixed pulley is arranged at the other end of the first air duct; each second fixed pulley is arranged at opposite ends of the second air duct; the third fixed pulley is arranged at opposite ends of the third air duct; the rope is wound in turn on the first fixed pulley, each second fixed pulley and each third fixed pulley, and the two ends of the rope are connected to the contraction drive winch and the expansion drive winch respectively. Further comprising a driver connected to the unmanned aerial vehicle; the contraction drive winch and the expansion drive winch are connected to the rotating shaft arranged on the driver.

2. The retractable jet device of claim 1, wherein, The diameter of the expansion drive winch is greater than the diameter of the contraction drive winch.

3. A retractable jet device according to any one of claims 1-2, characterized in that, The gimbal mechanism comprises a base, a roll axis and a pitch axis; one side end surface of the base is connected to the body of the unmanned aerial vehicle, one end of the pitch axis is connected to the other side end surface of the base; the roll axis is connected to the other end of the pitch axis; the roll axis is connected to the first air duct.

4. The retractable jet device of claim 1, wherein, A high-pressure gas source mechanism is arranged on the end surface of the base facing away from the unmanned aerial vehicle; the air outlet of the high-pressure gas source mechanism is aligned with the port of the third air duct.

5. The retractable jet device of claim 4, wherein, The gimbal mechanism further comprises a dual-shaft drive motor, which is communicatively connected to the control system of the unmanned aerial vehicle.

6. The retractable jet device of claim 4, wherein, The method is applied to the telescopic jet device of any one of claims 1-6, comprising:

7. A method of active disturbance rejection control, characterized in that Based on the gimbal mechanism, a base coordinate system, a roll axis coordinate system and a pitch axis coordinate system are respectively constructed, and based on each coordinate system, the angular velocity and mapping relationship between adjacent two coordinate systems, the inertia matrix of the pitch axis and the inertia matrix of the roll axis are derived; Based on the angular velocity and mapping relationship between adjacent two coordinate systems, the inertia matrix of the pitch axis and the inertia matrix of the roll axis, the gimbal mechanism is modeled and analyzed by Newton-Euler method based on the principle of moment balance, to obtain a coupled dynamics model taking pitch angular velocity and roll angular velocity as state variables; Based on the coupled dynamics model, pitch axis transfer function, roll axis transfer function, pitch axis direct disturbance transfer function and roll axis direct disturbance transfer function are established, and an inner loop controller is constructed based on each transfer function; Based on the inner loop controller, a preset first frequency weight function and a preset second frequency weight function, a hybrid sensitivity optimization objective function is constructed, and the outer loop robust controller is obtained by solving the hybrid sensitivity optimization objective function; Based on the Hankel singular value balance reduction, the outer loop robust controller is reduced to obtain an outer loop low-order robust controller; ​ Generate an active disturbance rejection control instruction based on the inner loop controller and the outer loop low-order robust controller.

8. Active disturbance rejection control method according to claim 7, characterized in that Based on the coupling dynamics model, establish a pitch axis transfer function, a roll axis transfer function, a pitch axis direct disturbance transfer function, and a roll axis direct disturbance transfer function, and build an inner loop controller based on each transfer function, including: Based on the coupling dynamics model, small perturbation linearization is performed on the pitch axis channel and the roll axis channel of the gimbal mechanism respectively to obtain a pitch axis transfer function, a roll axis transfer function, a direct disturbance transfer function of the pitch axis caused by external disturbance of the pitch axis, and a direct disturbance transfer function of the roll axis caused by external disturbance of the roll axis; Based on the pitch axis transfer function, the roll axis transfer function, the direct disturbance transfer function of the pitch axis, and the direct disturbance transfer function of the roll axis, build a pitch axis inner loop controller and a roll axis inner loop controller for disturbance compensation, respectively, wherein: The pitch axis inner loop controller is obtained by inverting the pitch axis transfer function and multiplying the result by the direct disturbance transfer function of the pitch axis; The roll axis inner loop controller is obtained by inverting the roll axis transfer function and multiplying the result by the direct disturbance transfer function of the roll axis.

9. The active disturbance rejection control method of claim 7, wherein, Based on the inner loop controller, a first preset frequency weight function, and a second preset frequency weight function, build a mixed sensitivity optimization objective function, and solve the mixed sensitivity optimization objective function to obtain an outer loop robust controller, including: Based on the inner loop controller, build the pitch axis channel and the roll axis channel of the gimbal mechanism into a controlled object transfer matrix with a double-input double-output structure; Based on the controlled object transfer matrix, build a sensitivity function and a complementary sensitivity function; Based on the first frequency weight function, perform weighted processing on the sensitivity function to obtain a weighted sensitivity function; Based on the second frequency weight function, perform weighted processing on the complementary sensitivity function to obtain a weighted complementary sensitivity function; Based on the weighted sensitivity function and the weighted complementary sensitivity function, build the mixed sensitivity optimization objective function; Minimize the mixed sensitivity optimization objective function, and build the outer loop robust controller based on the control parameter set obtained by solving.

10. A drone, characterized in that, The scalable air jet device of any one of claims 1-6, further comprising an active disturbance rejection control system, the active disturbance rejection control system comprising a processor configured to perform the inner loop controller and the outer loop robust controller of any one of claims 7-9.

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