Fixed-wing unmanned aerial vehicle air docking method, system and device

Abstract

The invention discloses an air docking method and device for a fixed-wing unmanned aerial vehicle. The method comprises the following steps: acquiring position and attitude information of the unmanned aerial vehicle; according to the position relation between the target unmanned aerial vehicle and the docking unmanned aerial vehicle, the current unmanned aerial vehicle docking track is calculated, and instruction output is carried out according to the input requirement of the flight controller. According to the method provided by the invention, task planning, trajectory design and multi-sensor information fusion are integrated, mutual docking of the fixed-wing unmanned aerial vehicles in the air is realized, and the use methods of the unmanned aerial vehicles are more diversified.

Description

Technical Field

[0001] The invention discloses a method and a device for air docking of fixed-wing unmanned aerial vehicles, which can realize the air docking of fixed-wing unmanned aerial vehicles. Background Art

[0002] Drones have been widely used in many fields such as military, agriculture, logistics, and electricity. In addition to improving the performance of single machines, countries are also vigorously developing autonomous drone technology. The technology of autonomous drone docking and recovery on land, sea, and air is constantly developing to meet the needs of future drone clusters.

[0003] Based on different landing platform environments, the docking methods and requirements of drones are also different. In existing research, China's invention application "A method for autonomous aerial docking of drones based on binocular stereo vision" (publication number: CN116860000A, publication date: October 10, 2023) based on the trajectory planning method of model predictive control, constructs a docking control method based on PID-disturbance observer, and realizes the planning of the aerial docking trajectory of fixed-wing drones. China's invention application "A precise docking control method for aerial recovery of fixed-wing drones based on direct force control" (publication number: CN117170409A, publication date: December 5, 2023) based on direct force control, selects a suitable combination of control surfaces, keeps the pitch attitude of the drone unchanged, establishes a vertical translation mode, and realizes the aerial docking recovery of fixed-wing drones. China's invention application "Control method and system for precise docking of mother-and-child aircraft for aerial charging of a quad-rotor drone" (publication number: CN113900453A, publication date: January 7, 2022) obtains horizontal position information through a visual processing module and altitude information through a laser rangefinder, which are respectively transmitted to the horizontal position controller and altitude controller to control the quad-rotor drone to land precisely. Summary of the invention

[0004] Purpose of the invention: The present invention discloses a method and device for fixed-wing UAV aerial docking. The provided method integrates task planning, trajectory design, and multi-sensor information fusion to achieve fixed-wing UAVs docking with each other in the air, making the use of UAVs more diversified.

[0005] Technical solution: To solve the above technical problems, the technical solution adopted by the present invention is:

[0006] In the first aspect, a method for air docking of a fixed-wing UAV is provided. When the horizontal coordinate error between the UAV and the mobile platform is within a preset range, a docking recovery task is performed, and during the docking recovery task, only the vertical position and attitude of the UAV and the mobile platform are adjusted:

[0007] At time t, the drone moves in the vertical direction at an exponential function. The form of the UAV is close to the mobile platform, and the horizontal speed change curve of the UAV in the landing mission is designed. , and impose restrictions on drone docking area terminals , y u is the coordinate of the UAV in the y-axis direction in the geodetic coordinate system during the docking and recovery mission, y f0 is the coordinate of the mobile platform relative to the UAV body coordinate system in the y-axis direction at the initial moment of the docking and recovery mission, Δy is the height difference between the UAV and the mobile platform during the docking and recovery mission in the new coordinate system, Δx is the horizontal interval between the UAV and the mobile platform during the docking and recovery mission in the new coordinate system, Δx0 is the horizontal interval between the UAV and the mobile platform at the initial moment of the docking and recovery mission in the new coordinate system, θ is the angle between the mobile platform speed and the ground, and v ux is the speed of the UAV in the x-axis direction of the geodetic coordinate system during the docking and recovery mission, v ux0 At the beginning of the docking recovery mission, the UAV is in the geodetic coordinate system. x The speed in the direction, k h is the height adjustment parameter, k v is the speed adjustment parameter, u fy k is the velocity of the mobile platform relative to the UAV body in the y-axis direction during the docking recovery mission, r is the task time parameter, x f is the coordinate of the mobile platform relative to the UAV body in the x-axis direction during the docking recovery mission, u It is the x-axis coordinate of the UAV in the geodetic coordinate system during the docking and recovery mission.

[0008] As a preferred solution of the present invention, the control amount of the UAV at any time during the docking recovery mission is:

[0009] Drone thrust , track angle ,in, is the resistance of the drone, v fx It is the speed of the mobile platform relative to the UAV body coordinate system in the x-axis direction during the docking recovery mission;

[0010] Design throttle change rate control rate ,in, is the proportional gain of the throttle control system, is the integral gain of the throttle control system, is the actual aircraft thrust, is the compensation coefficient of throttle delay, s is a complex variable;

[0011] The pitch angle of the drone is consistent with that of the mobile platform, and the following control rates are adopted for the elevation, rudder and deflection angles of the drone ,in, To calculate the pitch rate of the drone, is the actual UAV pitch rate, is the pitch angular acceleration of the drone, is the proportional gain of the pitch angular velocity control system of the UAV, is the integral gain of the pitch angular velocity control system of the UAV, is the proportional gain of the pitch angle control system of the UAV.

[0012] As a preferred solution of the present invention, the height adjustment parameter k h The expression is: , where is the relative height threshold between the UAV and the mobile platform when the docking condition between the UAV and the mobile platform is met, Δy0 is the height difference between the UAV and the mobile platform at the initial moment of the docking recovery mission, and y f0 It is the coordinate of the mobile platform in the y-axis direction relative to the UAV body coordinate system at the initial moment of the docking and recovery mission.

[0013] As a preferred solution of the present invention, the speed adjustment parameter k v The expression is: , where The minimum speed of the drone to meet the conditions for successful docking between the drone and the mobile platform. The minimum pitch angle of the drone when the drone and the mobile platform meet the conditions for successful docking, u uy0 It is the velocity of the UAV in the y-axis direction in the geodetic coordinate system at the initial moment of the docking and recovery mission.

[0014] In the second aspect, a fixed-wing UAV aerial docking system is also provided, comprising:

[0015] A state perception module, used to obtain state information of the UAV and the mobile platform, wherein the state information includes at least the speed and position of the UAV and the speed and position of the mobile platform;

[0016] Data storage module, used to store historical and real-time status information of the drone and docking platform;

[0017] A trajectory planning module, used to plan the UAV docking trajectory according to the method described in step (3) above;

[0018] The flight control module is used to calculate the control amount of the UAV in the trajectory planned by the trajectory planning module according to the method described in step (4) above.

[0019] According to a third aspect, an electronic device is provided, comprising one or more processors, one or more memories and one or more programs, wherein the one or more programs are stored in the one or more memories and are configured to be executed by the one or more processors, and the one or more programs include instructions for executing the method described above.

[0020] In a fourth aspect, a computer-readable storage medium storing one or more programs is also provided, wherein the one or more programs include instructions, and when the instructions are executed by a computing device, the computing device executes the method as described above.

[0021] Beneficial effects: The method of the present invention extends the landing of fixed-wing UAVs in a fixed area to the exponential landing of mobile targets, and decouples the mission track according to the flight control, thereby realizing the combination of track planning and flight control, making the UAV control smoother, and can be applied to fixed-wing UAVs without flaps. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a method flow chart of an embodiment of the present invention.

[0023] Figure 2 Schematic diagram of the docking of a UAV according to an embodiment of the present invention.

[0024] Figure 3 It is a schematic structural diagram of a docking device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0026] like Figure 1 As shown, the embodiment of the present invention discloses a method for air docking of a fixed-wing UAV, comprising the following steps:

[0027] (1) Obtain the position and attitude information of the UAV and mobile platform.

[0028] When the horizontal coordinate error between the UAV and the mobile platform is within a preset range (set to 0.5~1m in this embodiment), the docking recovery task is performed, and during the docking recovery task, only the vertical position and attitude of the UAV and the mobile platform are adjusted, and the initial moment of the docking recovery task and the position and attitude of the UAV and the mobile platform during the docking recovery task are obtained, including the speed of the UAV in the geodetic coordinate system at the initial moment of the docking recovery task =[v ux0 u uy0 ],Location =[x u0 y u0] and the speed of the mobile platform relative to the drone body coordinate system =[x f0 y f0 ] and location =[v fx0 u fy0 ], the speed of the UAV in the geodetic coordinate system during the docking and recovery mission and location And the position of the mobile platform relative to the drone body coordinate system and speed ; where v ux0 、u uy0 is the velocity of the UAV in the x and y axes in the geodetic coordinate system at the initial moment of the docking recovery mission, x u0 ,y u0 is the x- and y-axis coordinates of the UAV in the geodetic coordinate system at the initial moment of the docking recovery mission, v fx0 、u fy0 is the speed of the mobile platform relative to the UAV body in the x and y axis directions at the initial moment of the docking recovery mission, x f0 ,y f0 is the coordinates of the mobile platform relative to the UAV body in the x- and y-axis directions in the coordinate system at the initial moment of the docking recovery mission, v ux 、u uy is the speed of the UAV in the x and y axis directions in the geodetic coordinate system during the docking and recovery mission, x u ,y u is the coordinates of the UAV in the x-axis and y-axis directions in the geodetic coordinate system during the docking and recovery mission, v fx 、u fy is the speed of the mobile platform relative to the UAV body in the x and y axis coordinate system during the docking recovery mission, x f ,y f It is the coordinates of the mobile platform in the x- and y-axis directions relative to the UAV body coordinate system during the docking and recovery mission.

[0029] Specifically, the location information of the UAV and the mobile platform can be obtained through GPS, accelerometers, and visual sensors.

[0030] (2) Convert the coordinate systems of the drone and the mobile platform.

[0031] In this embodiment, the angle between the speed of the mobile platform and the ground is obtained as , the original UAV coordinate system vector is converted into Rotation, the rotation matrix is , get the new coordinates of the drone and mobile platform , , , ,in, , , , It is the new coordinates and speed information of the drone and mobile platform in the new coordinate system. , , , It is the coordinates of the UAV and mobile platform in the original geodetic coordinate system.

[0032] (3) Calculate the UAV docking trajectory based on dynamic exponential landing.

[0033] Specifically, the horizontal distance between the drone and the mobile platform As the dependent variable, the mission initial horizontal interval between the UAV and the mobile platform , the height of the drone is an exponential function Approach the mobile platform in the form of a drone to restrict the drone docking area terminal , where the height adjustment parameter , speed adjustment parameters , is the expected height of the trajectory of the UAV in the current state, is the initial flight height of the mobile platform, is the height difference between the drone and the mobile platform at the current moment, The height difference between the drone and the mobile platform at the initial moment. Design the horizontal speed change curve relative to the mobile platform ,in is the task time parameter (constant parameter, the default value can be set to 15, 20, 25), and the result is as follows Figure 2 Drone trajectory shown.

[0034] (4) Calculate the control amount of the UAV on this trajectory.

[0035] The track angle at any time is , UAV thrust ,in The drone is subject to resistance. Because the drone's thrust has a certain error due to the change in speed, the throttle response delay is taken into account, and the throttle is integrated to obtain the throttle control rate. ,in is the actual aircraft thrust. During this process, the pitch angle of the drone is consistent with the mobile platform, and the following control rate is adopted for the elevator rudder deflection angle of the drone ,in, To calculate the pitch rate of the drone, is the actual UAV pitch rate, is the pitch angular acceleration of the drone, is the proportional gain of the pitch angular velocity control system of the UAV, is the integral gain of the pitch angular velocity control system of the UAV, is the proportional gain of the pitch angle control system of the UAV.

[0036] The present invention is further described below based on data from an experiment.

[0037] Experimental example: A UAV and a mobile platform are about to perform a docking recovery mission. Figure 3 As shown, the weight of the drone is 3kg and the wingspan is 0.328m / s 2 , the air density is 1.29kg / m 3 , the drag coefficient is 0.08, and the information of the UAV and the mobile platform at a certain time after the docking recovery mission begins is shown in Table 1:

[0038] Table 1

[0039]

[0040] The following will use a fixed-wing UAV docking method proposed by this method to calculate the trajectory and control amount of the UAV at the next moment:

[0041] (1) When the angle between the mobile platform speed and the ground is , the original target drone coordinate system vector is Rotation, the rotation matrix is , get the new coordinates of the drone and mobile platform , , , .in, , , , It is the new coordinate and speed information of the unmanned and mobile platform in the new coordinate system. , , , It is the coordinates of the UAV and mobile platform in the original geodetic coordinate system.

[0042] (2) Based on the information provided in the above figure, it is assumed that the drone needs to be above the mobile platform To complete the docking task, it is estimated that Mission accomplished. Height adjustment parameters , speed adjustment parameters , then the altitude of the drone is expected to be 0.1s later

[0043] ; The speed of the drone is

[0044] .

[0045] (3) The track angle at 0.1s from the start of the mission is

[0046] ;

[0047] At this time, the thrust of the drone is

[0048] .

[0049] like Figure 3 As shown, an embodiment of the present invention discloses a fixed-wing UAV aerial docking device, including: a UAV state perception module, a data storage module, a trajectory planning module, and a flight control module; wherein the UAV state perception module includes a UAV self-perception unit, a mobile platform perception unit, and a unit for respectively obtaining the speed and position data of the UAV and the speed and position data of the mobile platform. The data storage module includes a historical data unit and a real-time data unit, which are respectively used to store historical and real-time flight data; the trajectory planning module performs trajectory planning based on the UAV state perception module and the requirements of the exponential landing method; the flight control module calculates the control amount of the docking UAV on this docking trajectory in combination with the requirements of the mobile platform landing mission.

[0050] The fixed-wing UAV aerial docking device disclosed in this embodiment and the fixed-wing UAV aerial docking determination method embodiment belong to the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here.

[0051] Based on the same technical solution, the present invention also discloses a computer-readable storage medium storing one or more programs, wherein the one or more programs include instructions, which, when executed by a computing device, enable the computing device to execute the above-mentioned fixed-wing UAV aerial docking method.

[0052] Based on the same technical solution, the present invention also discloses an electronic device, including one or more processors, one or more memories and one or more programs, wherein the one or more programs are stored in the one or more memories and are configured to be executed by the one or more processors, and the one or more programs include instructions for executing the above-mentioned fixed-wing UAV aerial docking method.

[0053] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0054] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0055] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0056] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0057] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for aerial docking of a fixed-wing unmanned aerial vehicle, characterized in that: When the horizontal coordinate error between the drone and the mobile platform is within the preset range, the docking recovery mission is performed, and during the docking recovery mission, only the vertical position and attitude of the drone and the mobile platform are adjusted: At time t, the drone moves in the vertical direction at an exponential function. The form of the mobile platform is close to the horizontal speed change curve of the UAV landing mission. , and impose restrictions on drone docking area terminals , y u is the coordinate of the UAV in the y-axis direction in the geodetic coordinate system during the docking and recovery mission, y f0 is the coordinate of the mobile platform relative to the UAV body coordinate system in the y-axis direction at the initial moment of the docking and recovery mission, Δy is the height difference between the UAV and the mobile platform during the docking and recovery mission in the new coordinate system, Δx is the horizontal interval between the UAV and the mobile platform during the docking and recovery mission in the new coordinate system, Δx0 is the horizontal interval between the UAV and the mobile platform at the initial moment of the docking and recovery mission in the new coordinate system, θ is the angle between the mobile platform speed and the ground, and v ux is the speed of the UAV in the x-axis direction of the geodetic coordinate system during the docking and recovery mission, v ux0 At the beginning of the docking recovery mission, the UAV is in the geodetic coordinate system. x The speed in the direction, k h is the height adjustment parameter, k v is the speed adjustment parameter, u fy k is the velocity of the mobile platform relative to the UAV body in the y-axis direction during the docking recovery mission, r is the task time parameter, x f is the coordinate of the mobile platform relative to the UAV body in the x-axis direction in the docking recovery mission. u It is the x-axis coordinate of the UAV in the geodetic coordinate system during the docking and recovery mission.

2. The method according to claim 1, characterized in that The coordinate systems of the UAV and the mobile platform are rotated according to the angle θ between the mobile platform speed and the ground to obtain a new coordinate system.

3. The method according to claim 2, characterized in that Rotation Matrix .

4. The method according to claim 1, characterized in that: The control quantity of the UAV at any time during the docking and recovery mission is: Drone thrust , track angle ,in, is the resistance of the drone, v fx It is the speed of the mobile platform relative to the UAV body coordinate system in the x-axis direction during the docking recovery mission; Design throttle change rate control rate ,in, is the proportional gain of the throttle control system, is the integral gain of the throttle control system, is the actual aircraft thrust, is the compensation coefficient of throttle delay, s is a complex variable; The pitch angle of the drone is consistent with that of the mobile platform, and the following control rates are adopted for the elevation, rudder and deflection angles of the drone ,in, To calculate the pitch rate of the drone, is the actual UAV pitch rate, is the pitch angular acceleration of the drone, is the proportional gain of the pitch angular velocity control system of the UAV, is the integral gain of the pitch angular velocity control system of the UAV, is the proportional gain of the pitch angle control system of the UAV.

5. The method according to claim 1, characterized in that Height adjustment parameter k h The expression is: , where is the relative height threshold between the UAV and the mobile platform when the docking condition between the UAV and the mobile platform is met, Δy0 is the height difference between the UAV and the mobile platform at the initial moment of the docking recovery mission, and y f0 It is the coordinate of the mobile platform in the y-axis direction relative to the UAV body coordinate system at the initial moment of the docking and recovery mission.

6. The method according to claim 1, characterized in that Speed ​​adjustment parameter k v The expression is: , where The minimum speed of the drone to meet the conditions for successful docking between the drone and the mobile platform. The minimum pitch angle of the drone when the drone and the mobile platform meet the conditions for successful docking, u uy0 It is the velocity of the UAV in the y-axis direction in the geodetic coordinate system at the initial moment of the docking and recovery mission.

7. A fixed-wing UAV aerial docking system, characterized in that: include: A state perception module, used to obtain state information of the UAV and the mobile platform, wherein the state information includes at least the speed and position of the UAV and the speed and position of the mobile platform; Data storage module, used to store historical and real-time status information of the drone and docking platform; A trajectory planning module, used to plan the UAV docking trajectory according to the method described in step (3) of claim 1; The flight control module is used to calculate the control amount of the UAV in the trajectory planned by the trajectory planning module according to the method described in step (4) of claim 1.

8. An electronic device, characterized in that: The method comprises one or more processors, one or more memories and one or more programs, wherein the one or more programs are stored in the one or more memories and are configured to be executed by the one or more processors, and the one or more programs include instructions for executing the method as claimed in any one of claims 1 to 6.

9. A computer-readable storage medium storing one or more programs, wherein the one or more programs include instructions, characterized in that: When the instructions are executed by a computing device, the computing device is caused to perform the method according to any one of claims 1 to 6.

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