A fixed-wing unmanned aerial vehicle air low-speed target attack method

Abstract

The application relates to a fixed-wing unmanned aerial vehicle air low-speed target attack method, which takes unmanned aerial vehicle target discovery as a starting point, and the air target attack process comprises the following stages: a posture adjustment stage, a pre-attack stage and a retreat stage, wherein the posture adjustment stage is mainly used for preparing coarse alignment for the pre-attack stage; the pre-attack stage is the core of the attack method, realizes automatic alignment and attack of the unmanned aerial vehicle; and the retreat stage guarantees flight safety of the unmanned aerial vehicle. The attack process is detailed, the pre-attack accurate alignment method is clear, the unmanned aerial vehicle posture control law is designed, the unmanned aerial vehicle can be quickly maneuvered and guided to approach a target after a seeker discovers the target, further accurate alignment is completed based on the unmanned aerial vehicle posture control, automatic attack triggering conditions are improved, attack timeliness is guaranteed, air low-speed targets are effectively attacked, and unmanned aerial vehicle attack precision is improved.

Description

Technical Field

[0001] This invention belongs to the field of unmanned aerial vehicle (UAV) technology and relates to a method for attacking low-speed aerial targets by a fixed-wing UAV. Background Technology

[0002] With the increasingly widespread application of drones in modern warfare and the diversification of combat missions, especially with both sides using drones as offensive units and engaging in mutual counter-drone operations, existing effective counter-drone strategies mainly include drone early warning and monitoring, electronic jamming, laser interception, and artillery attacks. All of these methods require consideration of air superiority, deployment environment, deployment quantity, and deployment cost. Furthermore, while ground-based missile attacks are highly accurate in air combat, mounting them on drones is difficult, requires high drone flight performance, and is costly. Therefore, mounting artillery on drones has been considered. However, rotary-wing drones are limited by factors such as flight altitude, speed, loiter time, and payload weight. This invention, based on fixed-wing drones, describes a method for attacking aerial targets.

[0003] For aerial targets, considering that the initial stage of UAV operations is mainly for reconnaissance and attrition, small and medium-sized low-cost UAVs are often used to approach the target. Currently, in the research on weapons mounted on small and medium-sized UAVs, designs have emerged for mounting light weapons such as rifles to attack ground targets. However, to deal with low-speed aerial targets (vacuum speed ≤100km / h), new requirements have been put forward for the specific attack procedures, pre-attack methods, and attitude control strategies in UAV operations in order to ensure attack accuracy.

[0004] Therefore, in order to counter enemy small and medium-sized low-speed and low-cost drones from reconnaissance of our defensive deployments, penetration of our front-line defenses, and depletion of our manpower, and with the goal of effective attack, it is necessary to further improve the attack process, pre-attack methods, and drone attitude control laws for air-to-air combat. Summary of the Invention

[0005] Technical problems to be solved

[0006] To overcome the shortcomings of existing technologies, this invention proposes a method for attacking low-speed aerial targets by fixed-wing UAVs. This method can effectively defend against reconnaissance, surveillance, interference, and self-destruct attacks by low-speed aerial targets (vacuum speed ≤ 100 km / h). It refines the UAV combat process, clarifies the pre-attack strategy, designs the UAV attitude control strategy, reduces the UAV attitude adjustment time and flight distance, improves the automatic attack triggering conditions, ensures the timeliness of the attack, and improves the attack accuracy of fixed-wing UAVs carrying guns against aerial targets.

[0007] Technical solution

[0008] A method for attacking low-speed aerial targets by a fixed-wing unmanned aerial vehicle (UAV), characterized by the following steps: starting with the UAV detecting the target, the attack process includes: an attitude adjustment phase, a pre-attack phase, an attack phase, and a withdrawal phase; the process steps are as follows:

[0009] Attitude adjustment phase: After the drone locks onto the target, it adjusts its attitude based on the target altitude. To adjust its own flight altitude equal to target height This ensures that the drone and the target are on the same horizontal line;

[0010] At the same time, adjust the direction of the drone's nose to point at the target, so that the drone and the target are in a tail-chase or head-on relationship to complete the rough alignment;

[0011] Pre-attack phase: The drone approaches the target in a tail-chase or head-on manner, and quickly adjusts its pitch angle after entering the firing range. and yaw angle This allows the installed weapons to be precisely aimed at the target and to fire automatically when the attack conditions are met.

[0012] In the pre-attack phase, the UAV's flight attitude tracking and control involves longitudinal control via pitch tracking, which reduces the azimuth deviation angle. and pitch deviation angle Once the attack detection criteria are met, the engine maintains speed control.

[0013] The attack conditions are as follows: , For eye-to-eye distance, For the pitch deviation angle between the UAV and the target, The azimuth deviation angle between the UAV and the target, The radius of the projected circle on the side of the target that bears the attack. This represents the ammunition spread radius at the current sight distance.

[0014] Attack phase: This phase begins when the guns are fired and ends when all ammunition is used up, at which point the phase transitions to the withdrawal phase.

[0015] Withdrawal Phase: After the attack is completed, the drone quickly turns to avoid the target area;

[0016] During the rapid turn maneuver, the UAV implements longitudinal and lateral control.

[0017] The longitudinal control includes altitude control and pitch tracking control;

[0018] The lateral heading control includes azimuth tracking control and roll control;

[0019] The altitude control is based on the target flight altitude. Set the flight altitude of the drone Based on the drone's current flight altitude With flight altitude setpoint Calculate the pitch angle setpoint of the UAV ;

[0020] The pitch tracking control is based on the pitch deviation angle. Calculate the given pitch angle of the UAV Then, using the drone's pitch angle Pitch angle given quantity UAV pitch rate and the roll angle of the drone Calculate elevator setpoint deflection To enable the drone to track the ;

[0021] The azimuth tracking control is based on the azimuth deviation angle. Calculate the given value of the roll angle of the UAV ;

[0022] The roll control is based on the drone's maximum roll angle. Calculate the given value of the roll angle of the UAV Then, using the drone's roll angle... UAV roll angle given value UAV roll angular velocity Calculate the aileron deflection of the UAV To enable the drone to track the .

[0023] The target height To adjust its own flight altitude At this time, the UAV's longitudinal control is altitude control, and its lateral control is azimuth tracking control. This is achieved by adjusting the UAV's flight altitude. and yaw angle This causes height deviation and azimuth deviation angle Control is set to 0, engine maintains speed control; target altitude With its own flight altitude The relation is: ,in: For eye-to-air distance, Elevation angle of line of sight .

[0024] The attack conditions must meet three conditions: 1. Entry range: when the distance between the aircraft and the target... Less than or equal to 1.2 times the standard weapon range ,Right now When the target is considered to be within attack range, an attack mission is carried out within this distance; 2. Position locking: based on the distance between the aircraft and the target. Azimuth of line of sight UAV yaw angle and weapon mounting azimuth angle The required azimuth control range of the UAV to hit the target is calculated, and the azimuth deviation angle between the UAV and the target is determined. If certain conditions are met, the azimuth lock is considered successful; 3. Pitch lock: based on the distance between the aircraft and the viewpoint. Elevation angle of line of sight UAV pitch angle Weapon installation elevation angle The required elevation angle control range of the UAV to hit the target is calculated, and the pitch deviation angle between the UAV and the target meets the condition. If the pitch lock is successful, then the pitch lock is considered successful.

[0025] The azimuth deviation angle Under certain conditions: ,in: For line of sight azimuth, For the yaw angle of the drone, Install azimuth angles for weapons.

[0026] The pitch deviation angle satisfies the condition : ,in: For the height angle of the line of sight, For the drone's pitch angle, Elevation angles are installed on the weapons.

[0027] The ammunition dispersion radius at the current sight distance ,in: For the ammunition dispersion radius at the weapon's standard firing range, For standard weapon range, This refers to the distance between the aircraft and the viewer.

[0028] The evacuation condition for transitioning to the evacuation phase may be the distance between the aircraft and the evacuation point. To achieve minimum roll distance When the evacuation conditions are met, that is... The attack was halted and the withdrawal phase began.

[0029] The elevator provides a rudder deflection. To enable the drone to track the The calculation is as follows:

[0030]

[0031] in: , , , These are the elevator control parameters; , The pitch angle is given a setpoint control parameter; , , These are the pitch tracking control parameters.

[0032] The aileron setpoint deflection of the UAV To enable the drone to track the The calculation is as follows:

[0033]

[0034] in: , , For aileron control parameters; , , Set a control parameter for the roll angle.

[0035] A computer program product, characterized in that it includes computer-executable instructions, which, when executed, are used to implement the method for attacking low-speed aerial targets by a fixed-wing UAV.

[0036] Beneficial effects

[0037] This invention proposes a method for attacking low-speed aerial targets using a fixed-wing UAV. The attack process begins with the UAV detecting a target and consists of three phases: an attitude adjustment phase, a pre-attack phase, and a withdrawal phase. The attitude adjustment phase primarily prepares the UAV for coarse alignment during the pre-attack phase. The pre-attack phase is the core of this attack method, enabling the UAV to automatically align and attack. The withdrawal phase ensures the UAV's flight safety. Based on a conventional fixed-wing UAV equipped with artillery, this invention automatically enters the attack process upon target detection, adjusting its attitude during this period to attempt target alignment. Once the attack conditions are met, it automatically fires to attack the target.

[0038] The beneficial effects of this invention are:

[0039] (1) It helps to clarify the attack process of fixed-wing UAVs carrying guns attacking aerial targets;

[0040] (2) It is conducive to refining the functions of each stage of the attack process;

[0041] (3) It facilitates the rapid maneuvering of drones and their approach to targets;

[0042] (4) It helps to clarify the specific targeting methods and attack judgment conditions in the pre-attack phase;

[0043] (5) It is conducive to improving the attitude control law during the attack process;

[0044] (6) It helps improve the accuracy of attacks against low-speed aerial targets;

[0045] (7) It helps to improve the reliability and security of drone attacks. Attached Figure Description

[0046] Figure 1 Diagram of the drone attack phase

[0047] Figure 2 Flowchart of a drone attack Detailed Implementation

[0048] The present invention will now be further described in conjunction with the embodiments and accompanying drawings:

[0049] The core idea of ​​this invention is: In response to the mission requirements of UAV aerial combat attack accuracy, this invention proposes an automatic attack process, pre-attack strategy and corresponding attitude control method based on UAV flight performance, so that UAV can quickly adjust its attitude when tailing or head-on attacking low-speed targets in the air, and carry out automatic attack after alignment, thus ensuring the timeliness of UAV air combat and improving the attack accuracy of UAV.

[0050] To facilitate understanding of the technical solution, the coordinate system and symbols involved in this invention are explained below.

[0051] a) Ground coordinate system ONED

[0052] This invention relates to a drone with a short flight distance, which ignores the curvature of the Earth and uses the ground coordinate system as the inertial coordinate system. Origin O For any point on the ground, ON The axis points due north in the horizontal plane. OD The axis is perpendicular to the horizontal plane and points towards the Earth's center. OE The axis points due east in the horizontal plane.

[0053] b) Body coordinate system

[0054] origin The coordinate system is located at the center of mass of the UAV and is fixed to the UAV. Within the plane of symmetry of the drone and parallel to the design axis pointing towards the nose. Perpendicular to the plane of symmetry of the drone, pointing to the right side of the drone. In the plane of symmetry of the drone The axis is vertical and points downwards from the fuselage.

[0055] c) Main symbols and polarities

[0056] 1) Symbols related to the drone body

[0057] This is the current flight altitude of the drone, in meters (m), with upwards being positive.

[0058] The current flight altitude of the drone is given in meters (m), with upwards being positive.

[0059] The roll angle of the drone is expressed in degrees (°), and the axis of rotation is the body axis. With the axis of the machine body The angle between the vertical plane and the drone is positive when the drone rolls to the right;

[0060] Set the current roll angle of the drone in degrees (°), with right roll being positive;

[0061] This represents the maximum roll angle of the drone, in degrees (°), with right roll being positive.

[0062] The yaw angle of the drone is expressed in degrees (°). The projection of the axis onto the horizontal plane and ON The included angle of the shaft, with right yaw of the nose being positive;

[0063] The pitch angle of the drone is expressed in degrees (°). The angle between the axis and the horizontal plane is positive when the head is tilted upwards;

[0064] Set the current pitch angle of the UAV to a value in degrees (°), with pitch up being positive;

[0065] The angular velocity of the drone is expressed in degrees per second (° / s), relative to the body axis. Consistent;

[0066] The pitch rate of the UAV, in degrees per second (° / s), relative to the body axis. Consistent;

[0067] Give the elevator a deflection amount in degrees (°), with the lower deflection of the elevator surface trailing edge being positive;

[0068] The control deflection is given to the ailerons of the UAV in degrees (°). The upward deflection of the trailing edge of the left aileron control surface and the downward deflection of the trailing edge of the right aileron control surface are positive.

[0069] This represents the minimum roll distance for the drone, expressed in meters (m).

[0070] 2) Target-related symbols

[0071] The target flight altitude is expressed in meters (m), with upwards being positive.

[0072] The target radius is expressed in meters (m).

[0073] 3) Guide head related symbols

[0074] The elevation angle of the line of sight, in degrees (°), is the angle between the direction of the line of sight and the horizontal plane in the ground coordinate system, with the line of sight pointing to the horizontal plane being positive;

[0075] The azimuth angle of the line of sight is expressed in degrees (°). It is the angle between the line of sight and the longitudinal plane in the ground coordinate system, with the right side being positive.

[0076] The distance between the drone and the target, i.e., the drone-to-target distance, is expressed in meters (m).

[0077] 4) Symbols related to weapon installation

[0078] Assign azimuth angle to the weapon, in degrees (°), and weapon muzzle pointing and unmanned aerial vehicle system. Angles between planes are considered positive if the angle is to the right.

[0079] Elevation angles are installed on the weapon, in degrees (°), and the weapon muzzle pointing is integrated with the unmanned aerial vehicle system. Angles between planes, with the upper angle being positive;

[0080] The ammunition spread radius at the current target distance, in meters (m).

[0081] The ammunition spread radius at the weapon's standard firing range, expressed in meters (m).

[0082] Standard weapon range, measured in meters (m).

[0083] 5) Symbols indicating the relative relationship between the UAV and the target

[0084] The azimuth deviation angle is expressed in degrees (°).

[0085] Pitch deviation angle, in degrees (°);

[0086] This represents the altitude difference between the drone and the target, expressed in meters (m). It is positive when the target is higher than the drone.

[0087] Based on the flight performance of existing small and medium-sized UAVs, this invention uses a cannon with an integrated fire control system as the attack weapon. After the seeker detects the target, it uses the target's flight altitude... Quickly adjust the drone's flight altitude The height difference between the two Reduce, with a smaller viewing angle Target locked. However, even in this state, it cannot be guaranteed that the muzzle will be perfectly aligned with the target. Therefore, a pre-attack strategy and control law need to be designed to ensure that the muzzle is accurately aligned with the target and fires automatically at an appropriate distance. After firing, regardless of whether the target is hit, to ensure the drone's flight safety and to re-enter the attack state, the drone must be controlled to quickly withdraw from the target's location. After withdrawing from the vicinity of the target, the drone continues to search for the next target and re-enters the attack process.

[0088] The exemplary embodiments of the present invention are described in detail below based on the technical solution and with reference to the accompanying drawings. This example uses a low-speed, uniform linearly flying UAV (vacuum speed ≤ 100 km / h) as the attack target to illustrate the feasibility and effectiveness of the present invention, while enabling those skilled in the art to have a more thorough understanding of the present invention, but it should not be limited to targets moving in uniform linear motion.

[0089] like Figure 2 The diagram shows the drone attack process, starting with the drone detecting the target and detailing the various stages of the pursuit: attitude adjustment stage, pre-attack stage, attack stage, and withdrawal stage. The specific explanations are as follows.

[0090] The specific attack process is as follows: Figure 2 As shown.

[0091] a) Posture adjustment phase

[0092] After searching, detecting, and successfully locking onto the target, the drone automatically initiates the attack process. The drone then moves at the target altitude... To quickly adjust its own flight altitude At the same time, the drone's nose is adjusted to point towards the target, so that the drone and the target are in a tail-chase or head-on relationship to complete the rough alignment. When the distance between the drone and the target enters the firing range, the pre-attack phase begins.

[0093] During this phase, the UAV's longitudinal control is altitude control, and its lateral control is azimuth tracking control, achieved by adjusting the UAV's flight altitude. and yaw angle This causes height deviation and azimuth deviation angle Control is set to 0, and engine speed control is maintained.

[0094] Among them, the target flight altitude Based on the drone's current flight altitude Eye-to-eye distance and line of sight height The calculations yielded the following results:

[0095] (1)

[0096] In this embodiment: During the aerial cruise search phase, the fixed-wing UAV carrying the gun detects a target flying in a straight line at a constant speed, whose vacuum speed is lower than that of the UAV. The UAV's seeker quickly transitions from scanning mode to target lock mode, successfully acquiring the target. The UAV then enters the attack guidance phase, based on its current flight altitude. Eye-to-eye distance Elevation angle of line of sight And calculate the target flight altitude using formula (1) The drone uses an altitude control strategy to track the target altitude. Simultaneously, the UAV uses an azimuth tracking control strategy to track the azimuth deviation angle. This allows the drone to quickly maneuver, adjust its flight attitude, and approach the target, achieving coarse alignment and minimizing altitude deviation. and azimuth deviation angle The control is set to 0.

[0097] b) Pre-attack phase

[0098] The drone continues to approach the target either tail-to-tail or head-on, and once within firing range, quickly adjusts its pitch angle. and yaw angle This allows the mounted weapon to be precisely aimed at the target and automatically fire once the attack conditions are met. For ease of explanation, the side of the target that will be hit is projected as the radius. The circle. The criteria for detecting a drone attack include three conditions; if all three are met, munitions are automatically launched.

[0099] 1) Entering firing range

[0100] When the distance between the camera and the eye Less than or equal to 1.2 times the standard weapon range ,Right now When the target is considered to be within attack range, an attack mission can be carried out within this distance.

[0101] 2) Direction Locking

[0102] According to the distance of the machine eye Azimuth of line of sight UAV yaw angle and weapon mounting azimuth angle The required azimuth angle control range of the UAV to hit the target can be calculated, and the azimuth deviation angle between the UAV and the target can be determined. If certain conditions are met, the location is determined to be successfully locked.

[0103] 3) Pitch Lock

[0104] Similarly, based on the distance between the aircraft and the eye Elevation angle of line of sight UAV pitch angle Weapon installation elevation angle The required elevation angle control range of the UAV to hit the target can be calculated, and the pitch deviation angle between the UAV and the target can be determined. If certain conditions are met, pitch lock is considered successful.

[0105] Specifically, the attack detection criteria are as follows:

[0106] (2)

[0107] Among them, the azimuth deviation angle It can be seen through the azimuth angle of the line of sight UAV yaw angle and weapon mounting azimuth angle The calculation shows that:

[0108] (3)

[0109] Pitch deviation angle It can be seen from the height of the line of sight UAV pitch angle and weapon mounting elevation angle The calculation shows that:

[0110] (4)

[0111] Ammunition spread radius at current sight distance It can be determined by the ammunition dispersion radius at the weapon's standard firing range. Standard weapon range and eye distance The calculation shows that:

[0112] (5)

[0113] Once the drone's pre-attack phase is detected and its range, azimuth, and pitch are locked, it will automatically launch munitions to attack the target.

[0114] In this phase, the UAV's longitudinal control is pitch tracking control, while the lateral control maintains azimuth tracking control, further refining the UAV's flight attitude and minimizing azimuth deviation angles. and pitch deviation angle Once the attack detection criteria are met, the engine maintains speed control.

[0115] In the embodiment: During the attitude adjustment phase, the UAV is guided to approach the target and coarse alignment is completed, with the distance between the UAV and the target being determined. Once within the gun's firing range, the attack process transitions to the pre-attack phase. This phase primarily involves adjusting the UAV's attitude to achieve precise azimuth and pitch lock-on, while lateral control maintains azimuth tracking, further minimizing azimuth deviation. In the longitudinal direction, a pitch tracking control strategy is used to further reduce the pitch deviation angle. .

[0116] Based on line of sight azimuth UAV yaw angle Weapon installation azimuth angle And calculate the azimuth deviation angle using formula (3). Based on the elevation angle of the line of sight UAV pitch angle Weapon installation elevation angle And calculate the pitch deviation angle using formula (4). ; Ammunition dispersion radius based on standard weapon range Standard weapon range Eye-to-eye distance And use formula (5) to calculate the ammunition spread radius at the current sight distance. .

[0117] Furthermore, the targetable range of the current UAV attitude is calculated using the left side of the inequality in formula (2); the ammunition spread radius is based on the current target distance. Target radius The right side of the inequality in formula (2) calculates the target's target alignment range. When the target alignment range is within the target alignment range, formula (2) is passed, and the firing opportunity is reached. The UAV's onboard weapon then automatically fires to carry out the attack. If the target alignment condition cannot be passed due to environmental or other interference, the UAV will continue to align and determine whether the minimum roll distance between the UAV and the target is met. If the evacuation conditions are met, the process will proceed to the evacuation phase.

[0118] c) Attack Phase

[0119] After precise aiming during the pre-attack phase, the drone can fire. This phase begins at the moment of firing, and the attack time can be pre-loaded, determined by the amount of ammunition it carries. After depleting its ammunition, the drone enters the withdrawal phase, or the engagement is completed at the designated distance. To achieve minimum roll distance When the evacuation conditions are met, that is... The attack was halted and the withdrawal phase began.

[0120] d) Evacuation phase

[0121] Taking into account factors such as the drone's flight altitude, speed, maximum roll angle, and minimum measurement distance of the seeker, the minimum roll distance is pre-set before takeoff. When the drone enters the withdrawal phase, it quickly turns to avoid the target area.

[0122] This phase is based on the drone's current altitude. Altitude control is performed for altitude commands, using the drone's maximum roll angle. The command performs roll control to complete lateral navigation control. Specifically, the longitudinal control command is based on the drone's current altitude, the lateral control command is based on the drone's maximum roll angle, and the engine maintains speed control. This allows the drone to yaw away from the target area, ensuring flight safety and preparing for re-entering the attack sequence.

[0123] During this phase, the drone's longitudinal control is altitude control, and its lateral control is roll control. That is, the drone's current altitude is used as the altitude control command in the longitudinal direction, the drone's maximum roll angle is used as the roll angle command in the lateral direction, and the engine maintains speed control, so that the drone yaws away from the target area and ensures the drone's safety.

[0124] To support the UAV control logic in each attack phase, an adaptive attitude control strategy is designed. The control surfaces selected for this invention are the elevator and ailerons. The longitudinal control channel primarily uses the elevator to control the UAV's pitch angle, achieving altitude control and pitch tracking control. The lateral control channel uses the ailerons to control the UAV's azimuth angle, achieving roll control and azimuth tracking control. Flight speed control mainly relies on the throttle to control engine thrust, stabilizing the UAV's speed at the desired level.

[0125] Specifically, the longitudinal control channel has two main control modes: altitude control and pitch tracking control.

[0126] Altitude control to target flight altitude Set the flight altitude of the drone Based on the drone's current flight altitude With flight altitude setpoint Calculate the pitch angle setpoint of the UAV Pitch tracking control is based on pitch deviation angle. Calculate the given pitch angle of the UAV Further, using the drone's pitch angle... Pitch angle given quantity UAV pitch rate and the roll angle of the drone Calculate elevator setpoint deflection To enable the drone to track the .

[0127] The elevator control method is as follows:

[0128] (6)

[0129] In the formula:

[0130] , , , The elevator control parameters are set to 1.0, 0.2, 0, and 0.1 respectively.

[0131] , Set the pitch angle as a given control parameter, taking values ​​of 1.0 and 0.01 respectively;

[0132] , , The pitch tracking control parameters are set to 2.0, 0.2, and 0.1 respectively.

[0133] Specifically, the lateral control channel has two main control modes: azimuth tracking control and roll control.

[0134] Azimuth tracking control is based on azimuth deviation angle Calculate the given value of the roll angle of the UAV Roll control is based on the drone's maximum roll angle. Calculate the given value of the roll angle of the UAV Further, using the drone's roll angle UAV roll angle given value UAV roll angular velocity Calculate the aileron deflection of the UAV To enable the drone to track the .

[0135] The aileron control method is as follows:

[0136] (7)

[0137] In the formula:

[0138] , , The aileron control parameters are set to 1, 0.5, and 0.5 respectively.

[0139] , , Set the roll angle as a given control parameter, and set it to 1, 0.2, and 0 respectively.

[0140] Based on the above-mentioned attack process, pre-attack method and control law design for UAV aerial combat, a method for attacking low-speed or stationary targets in the air is developed using a fixed-wing UAV carrying a gun.

[0141] Finally, determine whether the drone mission is complete. If the drone's designated attack mission is completed, the attack process ends. If the mission needs to continue, proceed to step 1 to rediscover the target and launch an attack.

[0142] This invention first describes the general process of a UAV attacking an aerial target, starting with the UAV's target detection. This process mainly includes an attitude adjustment phase, a pre-attack phase, and a withdrawal phase. The attitude adjustment phase primarily prepares the UAV for coarse alignment in the pre-attack phase. The pre-attack phase is the core of this attack method, enabling the UAV to automatically align and attack. The withdrawal phase ensures the UAV's flight safety. Secondly, it details the attack determination conditions used in the pre-attack phase, mainly including azimuth locking in the lateral direction and pitch locking in the longitudinal direction, and automatically fires to attack the target after locking is achieved. Finally, it explains the control strategies involved in the entire attack process of this invention, achieving a closed-loop attack method.

[0143] As can be seen from the above, the present invention proposes an aerial target attack method for a fixed-wing UAV carrying a gun, which refines the attack process, clarifies the pre-attack precision aiming method, and designs the UAV attitude control law. After the seeker detects the target, it can quickly maneuver and guide the UAV to approach the target. Based on the attitude control of the UAV, it can complete further precision aiming, improve the automatic attack triggering conditions, ensure the timeliness of the attack, carry out effective attacks on low-speed aerial targets, and improve the attack accuracy of the UAV.

Claims

1. A method for attacking low-speed aerial targets by a fixed-wing unmanned aerial vehicle, characterized in that: Starting with the drone detecting the target, the attack process includes: attitude adjustment phase, pre-attack phase, attack phase, and withdrawal phase; the process steps are as follows: Attitude adjustment phase: After the drone locks onto the target, it adjusts its attitude based on the target altitude. To adjust its own flight altitude equal to target height This ensures that the drone and the target are on the same horizontal line; At the same time, adjust the direction of the drone's nose to point at the target, so that the drone and the target are in a tail-chase or head-on relationship to complete the rough alignment; Pre-attack phase: The drone approaches the target in a tail-chase or head-on manner, and quickly adjusts its pitch angle after entering the firing range. and yaw angle This allows the installed weapons to be precisely aimed at the target and to fire automatically when the attack conditions are met. In the pre-attack phase, the UAV's flight attitude tracking and control involves longitudinal control via pitch tracking, which reduces the azimuth deviation angle. and pitch deviation angle Once the attack detection criteria are met, the engine maintains speed control. The attack conditions are as follows: , For eye-to-eye distance, For the pitch deviation angle between the UAV and the target, The azimuth deviation angle between the UAV and the target, The radius of the projected circle on the side of the target that bears the attack. This represents the ammunition spread radius at the current sight distance. Attack phase: This phase begins when the guns are fired and ends when all ammunition is used up, at which point the phase transitions to the withdrawal phase. Withdrawal Phase: After the attack is completed, the drone quickly turns to avoid the target area; During the rapid turn maneuver, the UAV implements longitudinal and lateral control. The longitudinal control includes altitude control and pitch tracking control; The lateral heading control includes azimuth tracking control and roll control; The altitude control is based on the target flight altitude. Provide a setpoint for the drone's flight altitude Based on the drone's current flight altitude With flight altitude setpoint Calculate the pitch angle setpoint of the UAV ; The pitch tracking control is based on the pitch deviation angle. Calculate the given pitch angle of the UAV Then, using the drone's pitch angle Pitch angle given quantity UAV pitch rate and the roll angle of the drone Calculate elevator setpoint deflection To enable the drone to track the ; The azimuth tracking control is based on the azimuth deviation angle. Calculate the given value of the roll angle of the UAV ; The roll control is based on the drone's maximum roll angle. Calculate the given value of the roll angle of the UAV Then, using the drone's roll angle... UAV roll angle given quantity UAV roll angular velocity Calculate the aileron deflection of the UAV To enable the drone to track the .

2. The method for attacking low-speed aerial targets by a fixed-wing UAV according to claim 1, characterized in that: The target height To adjust its own flight altitude At this time, the UAV's longitudinal control is altitude control, and its lateral control is azimuth tracking control. This is achieved by adjusting the UAV's flight altitude. and yaw angle This causes height deviation and azimuth deviation angle Control is set to 0, engine maintains speed control; target altitude With its own flight altitude The relation is: ,in: For eye-to-eye distance, Elevation angle of line of sight .

3. The method for attacking low-speed aerial targets by a fixed-wing UAV according to claim 1, characterized in that: The attack conditions must meet three conditions:

1. Entry range: when the distance between the aircraft and the target... Less than or equal to 1.2 times the standard weapon range ,Right now When the target is considered to be within attack range, an attack mission is carried out within this distance; 2. Position locking: based on the distance between the aircraft and the target. Azimuth of line of sight UAV yaw angle and weapon mounting azimuth angle The required azimuth control range of the UAV to hit the target is calculated, and the azimuth deviation angle between the UAV and the target is determined. If certain conditions are met, the location is determined to be successfully locked.

3. Pitch lock: Based on the distance to the target eye Elevation angle of line of sight UAV pitch angle Weapon installation elevation angle The required elevation angle control range of the UAV to hit the target is calculated, and the pitch deviation angle between the UAV and the target meets the condition. If the pitch lock is successful, then the azimuth deviation angle is determined to be... Under certain conditions: ,in: For line of sight azimuth, For the yaw angle of the drone, Install the azimuth angle for the weapon; the elevation deviation angle satisfies the following conditions. : ,in: For the height angle of the line of sight, For the drone's pitch angle, Elevation angles are installed on the weapons.

4. The method for attacking low-speed aerial targets by a fixed-wing UAV according to claim 1, characterized in that: The ammunition dispersion radius at the current sight distance ,in: For the ammunition dispersion radius at the weapon's standard firing range, For standard weapon range, This refers to the distance between the aircraft and the viewer.

5. The method for attacking low-speed aerial targets by a fixed-wing UAV according to claim 1, characterized in that: The evacuation condition for transitioning to the evacuation phase is the distance between the aircraft and the eye. To achieve minimum roll distance When the evacuation conditions are met, The attack was halted and the withdrawal phase began.

6. The method for attacking low-speed aerial targets by a fixed-wing UAV according to claim 1, characterized in that: The elevator provides a rudder deflection. To enable the drone to track the The calculation is as follows: in: , , , These are the elevator control parameters; , The pitch angle is given a setpoint control parameter; , , These are the pitch tracking control parameters.

7. The method for attacking low-speed aerial targets by a fixed-wing UAV according to claim 1, characterized in that: The aileron setpoint deflection of the UAV To enable the drone to track the The calculation is as follows: in: , , For aileron control parameters; , , Set a control parameter for the roll angle.

8. A computer program product, characterized in that... It includes computer-executable instructions, which, when executed, are used to implement the fixed-wing UAV aerial low-speed target attack method as described in claims 1 to 7.

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