An unmanned aerial vehicle underwater launching tracking control model establishing method

Abstract

The application belongs to the technical field of unmanned aerial vehicle flight control, and particularly relates to an unmanned aerial vehicle underwater launching tracking control model establishing method. The method comprises the following steps: establishing an unmanned aerial vehicle underwater launching coordinate system; establishing an unmanned aerial vehicle underwater launching motion attitude mathematical model, establishing an unmanned aerial vehicle motion data mathematical model by using the center of gravity trajectory change and roll angle in each direction in the unmanned aerial vehicle motion process, and establishing an unmanned aerial vehicle underwater launching unmanned aerial vehicle motion correction mathematical model; establishing an unmanned aerial vehicle underwater launching tracking control scheme by using a nonlinear adaptive unmanned aerial vehicle motion correction mathematical model; establishing a tracking control mathematical model; and establishing a control model based on the unmanned aerial vehicle motion mathematical model. The unmanned aerial vehicle underwater launching tracking control model establishing method is based on an adaptive parameter control principle, and is designed to realize error convergence by using a tracking control model and a control function, so that the accuracy and efficiency of trajectory tracking in the unmanned aerial vehicle underwater motion process during underwater launching are effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of unmanned aerial vehicle (UAV) flight control technology, and particularly relates to a method for establishing an underwater launch tracking control model for UAVs. Background Technology

[0002] Trajectory control during drone flight is a fundamental function of drone use. The conventional method involves the user adjusting the drone's position and attitude based on observations or data from a mobile phone, allowing the drone to move along a designed trajectory to complete the corresponding task. Thanks to mature satellite positioning and remote observation technologies, this process is easily achieved in various schemes that use land-based or airborne vehicles as the drone's launch platform, and trajectory tracking and prediction are also quite simple. However, for drones based on underwater launch platforms (including various underwater vehicles) as the launch terminal, the actual trajectory tracking effect is poor due to the influence of many factors such as highly complex fluid flow, buoyancy, water pressure density, and platform maneuvering. This introduces uncertainty into the planning and use of underwater-launched drones. Although the above problems can be improved by compressing the underwater movement path, for specific equipment such as underwater vehicles that require covert operations, shortening the underwater path by surfacing is a very dangerous and counterproductive behavior. Summary of the Invention

[0003] The purpose of this invention is to provide a method for establishing an underwater launch tracking control model for optimizing unmanned aerial vehicle (UAV) control schemes, improving the quality of underwater launch UAV trajectory tracking, and enhancing the control effect of UAVs.

[0004] To achieve the above objectives, the present invention adopts the following technical solution.

[0005] A method for establishing an underwater launch tracking control model for unmanned aerial vehicles (UAVs) includes the following steps:

[0006] Stp1, Steps for establishing the underwater launch coordinate system for UAVs

[0007] Using the drone launch point as the origin of the coordinate system Established on the side located within sea level and pointing towards the launch direction An axis is established perpendicular to the upward direction of sea level. The axis is established based on the right-hand rule. The axis is used to obtain the sea level reference coordinate system. ;

[0008] Using the center of gravity of the underwater-launched drone as the origin of the coordinate system The direction of the underwater-launched drone's axis of symmetry pointing towards its head is taken as... The axis, located in the vertical plane upward and parallel to... Rays that intersect perpendicularly on the axis are The axis is established based on the right-hand rule. The axes are used to obtain the UAV body coordinate system. ;

[0009] by Let the origin be the coordinate system and the direction of the drone's velocity be the coordinate system. The axis, located in the vertical plane upward and parallel to... Rays that intersect perpendicularly on the axis are The axis is established based on the right-hand rule. The axis is used to obtain the UAV velocity coordinate system. ;

[0010] Stp2, Steps for establishing a mathematical model of the underwater launch motion attitude of a UAV

[0011] Specifically, this refers to establishing a mathematical model of UAV motion data using the changes in the center of gravity trajectory and roll angles in each direction during the UAV's movement.

[0012]

[0013]

[0014]

[0015] in For the reference coordinate system of the UAV at sea level Coordinates in;

[0016] 'a' is the roll angle of the drone, i.e. The angle between the axis and the vertical plane P, where the vertical plane P is the angle between the axis and the vertical plane P. axis and perpendicular to The plane; b. The pitch angle of the drone, i.e. shaft and The included angle between the planes; c is the yaw angle of the UAV, i.e. Axis in Plane projection and included angle; This refers to the UAV in the UAV body coordinate system. The velocity component below, ; The roll angular velocity of the drone. The pitch rate of the drone. Let be the yaw rate of the UAV; where sea ​​level reference coordinate system To the UAV body coordinate system The transformation matrix; where UAV body coordinate system to sea level reference coordinate system The transformation matrix;

[0017] Stp3, Establish a mathematical model for motion correction of underwater-launched UAVs.

[0018] Based on the aforementioned Stp1 and Stp2, an underwater launch and tracking control scheme for UAVs is established using a nonlinear adaptive UAV motion correction mathematical model. Specifically, it includes the following steps:

[0019] 3a. Establish a mathematical model of UAV parameters ;

[0020] in, The velocity of the drone in each direction; For each direction of deflection, For angular velocities in all directions, The moment of inertia in all directions; This is the quality matrix; It refers to the resultant torque function of the mass component, driving force, and resistance, where These are basis functions. is a constant coefficient, obtained through testing the drone; s is the maximum cross-sectional area of ​​the drone; L is the length of the drone; Where m is the density of water; m is the mass of the UAV; d is the disturbance torque;

[0021] 3b. Correcting the error of the UAV parameter mathematical model based on an adaptive method, defining... To account for errors in the mathematical model, the corrected torque resultant function is obtained. Substituting the parameters into the UAV parameter mathematical model yields the UAV motion correction mathematical model: ;

[0022] in , refers to the roll angle of the drone at different times; , refers to the yaw angle of the drone at different times, and n is the amount of data recorded;

[0023] Stp4, Establish a mathematical model for tracking control

[0024] Define error increment , , ;in Indicates the planned movement trajectory. For the actual trajectory of motion, and To obtain the tracking control function, the mathematical model of UAV motion correction can be transcribed into the mathematical model of UAV motion tracking:

[0025] ;

[0026] Stp5, Establishing a Control Mathematical Model Based on the UAV Motion Mathematical Model

[0027] The expansion of the UAV motion tracking mathematical model is obtained by expanding the first term using Taylor's formula and omitting higher-order terms. ; Obtain control parameters ,in It is a convergence control coefficient greater than 0, used to control the speed of convergence of tracking error.

[0028] A further improvement or preferred embodiment of the aforementioned method for establishing an underwater launch tracking control model for unmanned aerial vehicles (UAVs) is that, in step Stp5, when the UAV performs angular maneuvers, the control function is taken. ,in Not less than 0; corresponds to the Lyapunov function form .

[0029] A further improvement or optimization of the aforementioned method for establishing an underwater launch tracking and control model for UAVs involves simplifying the data solving process by considering only the UAV body coordinate system during the underwater launch trajectory tracking process. The velocity component pointing towards the head of the underwater-launched UAV along its axis of symmetry is calculated.

[0030] Its beneficial effects are as follows:

[0031] The underwater launch tracking control model establishment method of this application is based on the principle of adaptive parameter control. It is designed to achieve error convergence by using a tracking control model and control function, and to approximate the trajectory by using UAV motion feedback data. Under the premise of relatively less computation and data requirements, it effectively improves the accuracy and efficiency of trajectory tracking during the underwater motion of underwater-launched UAVs. Attached Figure Description

[0032] Figure 1 This is a flowchart illustrating the method for establishing an underwater launch tracking control model for unmanned aerial vehicles (UAVs) according to this application.

[0033] Figure 2 This is a schematic diagram of path prediction based on the method for establishing an underwater launch tracking control model for unmanned aerial vehicles. Figure 1 ;

[0034] Figure 3 This is a schematic diagram of path prediction based on the method for establishing an underwater launch tracking control model for unmanned aerial vehicles. Figure 2 . Detailed Implementation

[0035] The present invention will be described in detail below with reference to specific embodiments.

[0036] The underwater launch tracking and control model establishment method of this application is mainly aimed at various types of underwater-launched UAVs released by underwater vehicles and various deep-sea diving equipment. It is used for tracking the motion trajectory and attitude of underwater-launched UAVs, providing a basic control scheme for the control and use of UAVs. Underwater-launched UAVs are affected by ocean fluids and the motion attitude of the launch platform, making their motion process very complex. At the same time, the process of underwater-launched UAVs emerging from and entering the water is affected by factors such as changes in the medium and the state of the medium. It should be noted that this application mainly focuses on the trajectory tracking analysis of underwater-launched UAVs in the post-launch and pre-emergence stages.

[0037] In order to establish a parametric model of the motion and state of an underwater-launched UAV, it is necessary to determine the coordinate system and parameter basis. Therefore, the first step of the method for establishing the underwater launch tracking control model of the UAV in this application is to establish the corresponding calculation reference system.

[0038] Stp1, Steps for establishing the underwater launch coordinate system for UAVs

[0039] Using the drone launch point as the origin of the coordinate system Established on the side located within sea level and pointing towards the launch direction An axis is established perpendicular to the upward direction of sea level. The axis is established based on the right-hand rule. The axis is used to obtain the sea level reference coordinate system. ;

[0040] Using the center of gravity of the underwater-launched drone as the origin of the coordinate system The direction of the underwater-launched drone's axis of symmetry pointing towards its head is taken as... The axis, located in the vertical plane upward and parallel to... Rays that intersect perpendicularly on the axis are The axis is established based on the right-hand rule. The axes are used to obtain the UAV body coordinate system. ;

[0041] by Let the origin be the coordinate system and the direction of the drone's velocity be the coordinate system. The axis, located in the vertical plane upward and parallel to... Rays that intersect perpendicularly on the axis are The axis is established based on the right-hand rule. The axis is used to obtain the UAV velocity coordinate system. ;

[0042] In the context of underwater launch, the UAV in motion can be considered as a point, with its position being the same as the UAV's center of mass. Based on this, this application uses the motion of the UAV's center of mass and its rotation angle around the center of mass to define and analyze the UAV's trajectory and motion attitude. Specifically:

[0043] Stp2, Steps for establishing a mathematical model of the underwater launch motion attitude of a UAV

[0044] Specifically, this refers to establishing a mathematical model of UAV motion data using the changes in the center of gravity trajectory and roll angles in each direction during the UAV's movement.

[0045]

[0046]

[0047]

[0048] in For the reference coordinate system of the UAV at sea level Coordinates in;

[0049] 'a' is the roll angle of the drone, i.e. The angle between the axis and the vertical plane P, where the vertical plane P is the angle between the axis and the vertical plane P. axis and perpendicular to The plane; b. The pitch angle of the drone, i.e. shaft and The included angle between the planes; c is the yaw angle of the UAV, i.e. Axis in Plane projection and included angle; This refers to the UAV in the UAV body coordinate system. The velocity component below; The roll angular velocity of the drone. The pitch rate of the drone. Let be the yaw rate of the UAV; where sea ​​level reference coordinate system To the UAV body coordinate system The transformation matrix; where UAV body coordinate system to sea level reference coordinate system The transformation matrix, It is the velocity in all directions. ;

[0050] In particular, during actual analysis, for purposes such as platform data requirements, the above coordinate system can be transformed into the existing geodetic coordinate system, the Huo-Hai coordinate system, using a transformation matrix, so that further analysis and processing can be performed based on existing data.

[0051] In particular, due to the high stealth and poor visibility of underwater environments, the focus of tracking and control of underwater-launched UAVs is mostly on tracking their trajectory in the direction of motion. Therefore, in further research, roll changes perpendicular to the direction of motion are ignored, and a relevant model is built on this basis. Specifically:

[0052] Stp3, Establish a mathematical model for motion correction of underwater-launched UAVs.

[0053] Based on the aforementioned Stp1 and Stp2, an underwater launch tracking control scheme for UAVs is established using a nonlinear adaptive tracking control strategy. Specifically, it includes the following steps:

[0054] 3a. Establish a mathematical model of UAV parameters ;

[0055] in, The velocity of the drone in each direction; For each direction of deflection, For angular velocities in all directions, The moment of inertia in all directions; Here is the mass matrix in all directions; It refers to the resultant torque function of the mass component, driving force, and resistance, where These are basis functions. is a constant coefficient, obtained through testing the drone; s is the maximum cross-sectional area of ​​the drone; L is the length of the drone; Where m is the density of water; m is the mass of the UAV; d is the disturbance torque;

[0056] 3b. Correcting the error of the UAV parameter mathematical model based on an adaptive method, defining... To account for errors in the mathematical model, the corrected torque resultant function is obtained. Substituting the parameters into the UAV parameter mathematical model yields the UAV motion correction mathematical model: ;

[0057] in , refers to the roll angle of the drone at different times; , refers to the yaw angle of the drone at different times, and n is the amount of data recorded;

[0058] In current underwater launch processes, underwater UAVs primarily employ low-speed release and surfacing, followed by pre-launch adjustments and acceleration. Therefore, their underwater motion is relatively slow with a gently changing trajectory. In acquiring actual motion data, methods such as key point sampling or uniform sampling are typically used to establish and reconstruct the trajectory from sampled data. Trajectory errors between sampling points are unavoidable. To effectively reduce tracking errors and establish a more accurate trajectory tracking model, this application considers using data obtained through autonomous sampling combined with a tracking control function to achieve adaptive correction of the trajectory tracking. This enables continuous correction and synchronization based on the error between the predicted trajectory and the measured data, continuously compressing errors to provide more accurate trajectory tracking results. Specifically:

[0059] Stp4, Establish a mathematical model for tracking control

[0060] Define error increment , , ;in Indicates the planned movement trajectory. For the actual trajectory of motion, and To obtain the tracking control function, the mathematical model of UAV motion correction can be transcribed into the mathematical model of UAV motion tracking:

[0061] ;

[0062] As can be seen from the function of the above UAV motion mathematical model, the tracking control function... and It can track the mathematical model of UAV motion correction, and thus achieve tracking and control of the UAV's motion state;

[0063] Stp5, Establishing a Control Mathematical Model Based on the UAV Motion Mathematical Model

[0064] The expansion of the UAV motion tracking mathematical model is obtained by expanding the first term using Taylor's formula and omitting higher-order terms. ;

[0065] Define control parameters ,in It is a convergence control coefficient greater than 0, used to control the speed of convergence of tracking error;

[0066] To achieve motion tracking, it is necessary to ensure ; control parameters Substituting the first term of the UAV motion mathematical model into its expansion, we obtain... ;

[0067] Let saturation function Let the Lyapunov function be in the form of Then, in the two cases of the saturation function, we obtain:

[0068] During the tracking process, the tracking trajectory cannot be completely identical to the actual trajectory; that is, there is no... In such cases, the aforementioned control parameters can be used. This is used to control tracking errors and achieve stable convergence.

[0069] In practical applications, the aforementioned control parameters can ensure that the trajectory convergence result of motion tracking meets the requirements. However, when the UAV performs complex angular maneuvers or other specific actions, the convergence efficiency is limited, and the computational load increases rapidly. Therefore, the second term of the UAV motion tracking mathematical model is further considered. ; Take control function ,in Not less than 0; corresponds to the Lyapunov function form Under this control function, the second term of the motion tracking mathematical model is transformed as follows: .

[0070] Based on the aforementioned scheme, an underwater launch test of a certain type of AUV was conducted to introduce the specific implementation of this scheme.

[0071] The underwater launch platform for the unmanned aerial vehicle (UAV) is a streamlined X-shaped submersible with rudders. The corresponding underwater UAV is a folding-wing UAV, which is in a folded state before emerging from the water, resembling a projectile with tail fins. The test results are as follows: Figure 2 , Figure 3 As shown.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for establishing an underwater launch tracking control model for unmanned aerial vehicles (UAVs), characterized in that, Includes the following steps: Stp1, Steps for establishing the underwater launch coordinate system for UAVs Using the drone launch point as the origin of the coordinate system Established on the side located within sea level and pointing towards the launch direction An axis is established perpendicular to the upward direction of sea level. The axis is established based on the right-hand rule. The axis is used to obtain the sea level reference coordinate system. ; Using the center of gravity of the underwater-launched drone as the origin of the coordinate system The direction of the underwater-launched drone's axis of symmetry pointing towards its head is taken as... The axis, located in the vertical plane upward and parallel to... Rays that intersect perpendicularly on the axis are The axis is established based on the right-hand rule. The axes are used to obtain the UAV body coordinate system. ; by Let the origin be the coordinate system and the direction of the drone's velocity be the coordinate system. The axis, located in the vertical plane upward and parallel to... Rays that intersect perpendicularly on the axis are The axis is established based on the right-hand rule. The axis is used to obtain the UAV velocity coordinate system. ; Stp2, Steps for establishing a mathematical model of the underwater launch motion attitude of a UAV Specifically, this refers to establishing a mathematical model of UAV motion data using the changes in the center of gravity trajectory and roll angles in each direction during the UAV's movement. in For the reference coordinate system of the UAV at sea level Coordinates in; 'a' is the roll angle of the drone, i.e. The angle between the axis and the vertical plane P, where the vertical plane P is the angle between the axis and the vertical plane P. axis and perpendicular to The plane; b is the pitch angle of the UAV, i.e. shaft and The included angle between the planes; c is the yaw angle of the UAV, i.e. Axis in Plane projection and included angle; This refers to the UAV in the UAV body coordinate system. The velocity components in each direction are below. ; The roll angular velocity of the drone. The pitch rate of the drone. Let be the yaw rate of the UAV; where sea ​​level reference coordinate system To the UAV body coordinate system The transformation matrix; where UAV body coordinate system to sea level reference coordinate system The transformation matrix; Stp3, Establish a mathematical model for motion correction of underwater-launched UAVs. Based on the aforementioned Stp1 and Stp2, an underwater launch and tracking control scheme for UAVs is established using a nonlinear adaptive UAV motion correction mathematical model. Specifically, it includes the following steps: 3a. Establish a mathematical model of UAV parameters ; in, The velocity of the drone in each direction; For each direction of deflection, For angular velocities in all directions, The moment of inertia in all directions; Here is the mass matrix in all directions; It refers to the resultant torque function of the mass component, driving force, and resistance, where These are basis functions. is a constant coefficient, obtained through testing the drone; s is the maximum cross-sectional area of ​​the drone; L is the length of the drone; Where m is the density of water; m is the mass of the UAV; d is the disturbance torque; 3b. Correcting the error of the UAV parameter mathematical model based on an adaptive method, defining... To account for errors in the mathematical model, the corrected torque resultant function is obtained. Substituting the parameters into the UAV parameter mathematical model yields the UAV motion correction mathematical model: ; in , refers to the roll angle of the drone at different times; , refers to the yaw angle of the drone at different times, and n is the amount of data recorded; Stp4, Establish a mathematical model for tracking control Define error increment , , ;in Indicates the planned movement trajectory. For the actual trajectory of motion, and To obtain the tracking control function, the mathematical model of UAV motion correction can be transcribed into the mathematical model of UAV motion tracking: ； Stp5, Establishing a Control Mathematical Model Based on the UAV Motion Mathematical Model The expansion of the UAV motion tracking mathematical model is obtained by expanding the first term using Taylor's formula and omitting higher-order terms. ; Obtain control parameters ,in It is a convergence control coefficient greater than 0, used to control the speed of convergence of tracking error.

2. The method for establishing an underwater launch tracking control model for unmanned aerial vehicles according to claim 1, characterized in that, In step Stp5, when the UAV performs angular maneuvers, the control function is retrieved. ,in Not less than 0; corresponds to the Lyapunov function form .

3. The method for establishing an underwater launch tracking control model for unmanned aerial vehicles according to claim 1, characterized in that, In the process of tracking the underwater launch trajectory of a UAV, to simplify the data solution steps, only the UAV body coordinate system is considered. The velocity component pointing towards the head of the underwater-launched UAV along its axis of symmetry is calculated.

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