A UAV cluster target tracking method and system based on variable gain strategy

Abstract

The present invention discloses a method and system for tracking a target of a swarm of unmanned aerial vehicles (UAVs) based on an independent variable gain strategy. In the flight control of the swarm of unmanned aerial vehicles (UAVs) tracking a target, an independent variable gain term is used to replace the fixed gain term of the UAV speed control to adjust the flight speed of each UAV separately. The variable of the independent variable gain term is the difference between the attraction radius and the distance from the UAV to the target position. The attraction radius is a given critical value. When the distance between the UAV and the target is greater than the critical value, the target tracking algorithm generates a variable flight speed to ensure that the UAV is stable within a certain distance range of the target. By using the direction vector and the difference between the attraction radius and the distance from the UAV to the target position as the determining terms of the UAV's flight speed, a dynamic association between the flight speed and the distance between the UAV and the target can be achieved. When the distance between the UAV and the target is far, the UAV approaches quickly. When the distance is close, the speed changes smoothly, ensuring that the UAV can both quickly track the target and stabilize within a certain distance range of the target.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicle (UAV) cluster control, and in particular to a UAV cluster target tracking method and system based on an independent variable gain strategy. Background Art

[0002] Unmanned, intelligent, and swarming are inevitable trends in the future development of aircraft technology. UAV swarm systems will become a key research and development area. While UAVs offer the advantages of low cost, rapid replenishment, and large-scale deployment, they face significant challenges in complex real-world environments. Firstly, they have limited payload and fault tolerance; if damaged, they terminate their missions, resulting in low mission efficiency. Furthermore, individual UAVs lack the intelligence of manned aircraft, limiting their adaptability and survivability in challenging environments such as those with strong interference and highly dynamic adversarial denial. Multi-UAV collaboration can address these challenges, significantly expanding mission capabilities and improving efficiency. In particular, if UAV swarm systems possess high levels of swarm intelligence, they can achieve a multiplier effect, achieving a multiplier effect. Through distributed decision-making, they enable self-organizing, coordinated, and robust swarm flight. Achieving this goal relies on robust UAV system autonomy. This differs from automatic control in that it emphasizes autonomous decision-making by the UAV itself, rather than relying solely on command execution. Therefore, algorithms must be designed to enhance UAV autonomy for different swarming tasks.

[0003] A common task for drone swarm systems is target tracking, such as tracking enemy vehicles for attack or tracking friendly targets for observation, protection, and support. This requires drones to quickly move to the target location while remaining within a certain distance. The drone's motion should be smooth, minimizing oscillation. Current target tracking methods for drone swarms typically use a P regulator. This fixed gain approach has numerous drawbacks. If the gain is too small, rapid movement to the target becomes difficult, resulting in a long delay and potentially causing mission failure. If the gain is too large, it becomes difficult to remain within a certain distance of the target, causing oscillation, impacting the safety of the swarm flight, and preventing the scheduled mission from being completed promptly.

[0004] To achieve fast and accurate target tracking for drone swarms, a variable gain strategy is needed to dynamically adjust the gain term. Drone speed cannot be controlled simply with a proportional regulator. Traditional PID controllers are widely used, but because they only have a fixed gain term, a drawback is that if the drones are expected to reach a high speed at a distance to quickly approach the target, they will not be able to quickly adjust their speed to zero and stabilize once they approach the target. Instead, the high speed will cause oscillations, which can prevent the drone swarm from continuing to perform reconnaissance, strike, and other missions after completing target tracking. Conversely, to ensure that the drones quickly stabilize within a certain distance of the target, the drone swarm will track the target at a slower speed. Summary of the Invention

[0005] In view of this, the present invention provides a UAV cluster target tracking method based on an independent variable gain strategy, which can quickly track the target and stabilize within a certain distance range of the target to avoid oscillation.

[0006] The specific technical solutions adopted in the present invention are as follows:

[0007] A UAV swarm target tracking method based on an independent variable gain strategy is proposed. In the flight control of the UAV swarm tracking target, the fixed gain term of the UAV speed control is replaced by an independent variable gain term to adjust the flight speed of each UAV separately.

[0008] The variable of the independent gain term is determined according to the difference between the attraction radius and the distance from the UAV to the target position;

[0009] The attraction radius is the safe distance between a given drone and a target location.

[0010] Furthermore, the variable gain term is the product of the adaptive control function and the fixed gain term; the variable gain term is expressed as K targ ·f targ (||p i -p targ ||); where K targ represents the fixed gain term, f targ (||p i -p targ ||)=||p i -p targ || represents the adaptive control function; P i represents the coordinate vector of UAV i, P targ Represents the coordinate vector of the target position, and |||| represents the modulo operation.

[0011] Furthermore, the flight speed of the UAV is determined by the independent gain term and the difference between the attraction radius and the distance from the UAV to the target position; the flight speed of the UAV is:

[0012] v i，targ =K targ ·f targ (||p i -p targ ||)·min{(r att -||P i -P targ ||), 0)·D i，targ

[0013] Among them, v i,targ is the flight speed of the UAV; min{(r att -||P i -P targ ||), 0} represents the attraction radius r att The difference between the distance from the drone to the target position. When the distance from the drone to the target position is less than the attraction radius, it is 0; when the distance from the drone to the target position is greater than the attraction radius, it is the difference between the attraction radius and the distance from the drone to the target position, and it is a negative value. att represents the attraction radius; is a direction vector used to describe the direction from the target to the drone i.

[0014] A UAV cluster target tracking system based on an auto-variable gain strategy includes: an auto-variable gain module, a difference module, an attraction radius setting module and a speed module;

[0015] The variable gain module is used to provide the speed module with a variable gain term to replace the fixed gain term of the UAV speed control;

[0016] The difference module is used to calculate the difference between the attraction radius and the distance from the UAV to the target position, and provide the difference as a variable of the independent gain term to the independent gain module;

[0017] The attraction radius setting module is used to provide the attraction radius for the difference module; the attraction radius is a safe distance between the given drone and the target location;

[0018] The speed module is used to adjust the flight speed of each UAV according to the independent variable gain item provided by the independent variable gain module.

[0019] Furthermore, in the independent variable gain module, the independent variable gain term is obtained by calculating the product of the adaptive control function and the fixed gain term;

[0020] The independent gain term is expressed as K targ ·f targ (||p i -p targ ||); where Ktarg represents the fixed gain term, f targ (||p i -p targ ||)=||p i -p targ || represents the adaptive control function; P i represents the coordinate vector of UAV i, P targ Represents the coordinate vector of the target position, and |||| represents the modulo operation.

[0021] Furthermore, in the speed module, the flight speed of the UAV is determined by the independent variable gain term and the difference between the attraction radius and the distance from the UAV to the target position;

[0022] The flight speed of the UAV is:

[0023] v i，targ =K targ ·f targ (||p i -p targ ||)·min{(r att -||P i -P targ ||), 0}·D i，targ

[0024] Among them, v i,targ is the flight speed of the UAV; min{(r att -||P i -P targ ||), 0} represents the difference between the attraction radius and the distance from the drone to the target position. When the distance from the drone to the target position is less than the attraction radius, it is 0; when the distance from the drone to the target position is greater than the attraction radius, it is the difference between the attraction radius and the distance from the drone to the target position, and it is a negative value; r att represents the attraction radius; is a direction vector that describes the direction from the target to the drone i.

[0025] Beneficial effects:

[0026] (1) A method for tracking target swarms of UAVs based on an auto-variable gain strategy. In the flight control of the UAV swarm tracking target, the auto-variable gain term replaces the fixed gain term of the UAV speed control to adjust the flight speed of each UAV separately. Instead of simply controlling the UAV to approach the target position, the UAV is made to generate an adaptive flight speed outside the target's attraction radius, thereby achieving target tracking. The attraction radius is a given critical value. When the distance between the UAV and the target is greater than this critical value, the target tracking algorithm will generate a variable flight speed to ensure that the UAV is stable within a certain distance range of the target.

[0027] (2) The independent variable gain term is the product of the adaptive control function and the fixed gain term. The fixed gain term can directly affect the speed of the drone when tracking the target, the time it takes to approach the target, and the speed of the drone's speed change. The adaptive control function can dynamically obtain a variable value according to the distance, and then multiply it by the fixed gain term to dynamically change the overall size of the independent variable gain term, so that the closer the drone is to the target, the smaller the independent variable gain term, and the smoother the change in the drone's flight speed. This avoids the oscillation phenomenon caused by the high flight speed and ensures that the drone cluster can continue to perform reconnaissance, strike and other tasks after completing target tracking.

[0028] (3) The difference between the direction vector and the attraction radius and the distance from the drone to the target position is used as the determining factor for the drone's flight speed, which ensures that the direction of the flight speed is consistent with the actual flight direction required by the drone. This achieves a dynamic correlation between the flight speed and the distance between the drone and the target. When the distance is far, the drone approaches quickly, and when the distance is close, the speed changes smoothly, ensuring that the drone can both quickly track the target and remain stable within a certain distance range of the target. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a flow chart of a UAV cluster target tracking method based on the variable gain strategy. DETAILED DESCRIPTION

[0030] A method and system for tracking target swarms of unmanned aerial vehicles (UAVs) based on an independent variable gain strategy. In the flight control of a UAV swarm tracking target, an independent variable gain term replaces the fixed gain term used in the UAV speed control to adjust the flight speed of each UAV individually. The independent variable gain term is the difference between the attraction radius and the distance between the UAV and the target. The attraction radius is a given critical value. When the distance between the UAV and the target exceeds this critical value, the target tracking algorithm will generate a variable flight speed to ensure that the UAV remains stable within a certain distance range of the target.

[0031] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0032] like Figure 1 As shown, there is no strict order in the process of obtaining the drone position, target position, attraction radius, calculating distance and difference. In order to clearly demonstrate the technical solution of this method, a detailed description of the technical solution is given in the form of a flowchart and steps.

[0033] First, obtain the coordinate vector P of drone i i , the coordinate vector P of the target position targ ; Given the attraction radius r att .

[0034] Afterwards, it is determined whether the distance between the drone and the target is greater than the attraction radius, min{(r att -||P i -P targ ||), 0}. When the distance from the drone to the target is less than the attraction radius, it is 0. When the distance from the drone to the target is greater than the attraction radius, it is the difference between the attraction radius and the distance from the drone to the target, and is a negative value. |||| represents a modulo operation.

[0035] Afterwards, calculate the direction vector Used to describe the direction from the target to the drone i.

[0036] Afterwards, the adaptive control function f for target tracking is calculated targ (||p i -p targ ||)=||p i -p targ ||, this item is used to implement the self-variable gain strategy. The greater the distance between the drone and the target, the greater the self-variable gain item.

[0037] After that, the variable gain term is calculated, which is the product of the adaptive control function and the fixed gain term. The variable gain term is expressed as K targ ·f targ (||p i -p targ ||); where K targ represents the fixed gain term, f targ (||p i -p targ ||)=||p i -p targ || represents the adaptive control function.

[0038] Finally, calculate the flight speed of the drone. The flight speed of the drone is determined by the independent gain term and the difference between the attraction radius and the distance from the drone to the target position; the flight speed of the drone is:

[0039] v i，targ =K targ ·f targ (||p i -p targ ||)·min{(r att -||P i -P targ ||), 0)·D i，targ

[0040] Among them, v i,targ is the flight speed of the UAV; min{(r att -||Pi -P targ ||), 0} represents the difference between the attraction radius and the distance from the drone to the target position. When the distance from the drone to the target position is less than the attraction radius, it is 0; when the distance from the drone to the target position is greater than the attraction radius, it is the difference between the attraction radius and the distance from the drone to the target position, and it is a negative value; r att represents the attraction radius; is a direction vector used to describe the direction from the target to the drone i.

[0041] The aforementioned drone swarm target tracking method enables drones to generate an adaptive attraction velocity, or automatically varying flight speed, when approaching a target. This attraction velocity occurs only when the distance between the drone and the target is greater than the attraction radius. The drone swarm target tracking method modifies both the magnitude and direction of the drone's velocity. The direction of the drone's flight velocity depends on the drone's distance from the target and is the direction in which the drone approaches the target.

[0042] In this implementation, the drone is equipped with a navigation and positioning device, a communication device, and a control device. The control device comprises a motion controller and a cluster controller. The cluster controller sends velocity commands to the motion controller using a target tracking algorithm. The variable gain strategy adjusts the automatic gain term based on the drone's distance from the target.

[0043] According to the above-mentioned UAV cluster target tracking method based on the self-variable gain strategy, the present invention also provides a UAV cluster target tracking system based on the self-variable gain strategy, including: an self-variable gain module, a difference module, an attraction radius given module and a speed module.

[0044] The variable gain module is used to provide the speed module with a variable gain term instead of the fixed gain term of the drone speed control.

[0045] The difference module is used to calculate the difference between the attraction radius and the distance from the drone to the target position, and provide the difference as the variable of the independent gain term to the independent gain module.

[0046] The attraction radius setting module is used to provide the attraction radius for the difference module; the attraction radius is the safe distance between the given drone and the target position.

[0047] The speed module is used to adjust the flight speed of each UAV according to the independent gain item provided by the independent gain module.

[0048] In the independent variable gain module, the independent variable gain term is obtained by calculating the product of the adaptive control function and the fixed gain term.

[0049] The independent gain term is expressed as K targ ·ftarg (||p i -p targ ||); where K targ represents the fixed gain term, f targ (||p i -p targ ||)=||p i -p targ || represents the adaptive control function; P i represents the coordinate vector of UAV i, P targ Represents the coordinate vector of the target position, and |||| represents the modulo operation.

[0050] In the speed module, the flight speed of the drone is determined by the independent gain term and the difference between the attraction radius and the distance from the drone to the target position;

[0051] The flight speed of the drone is:

[0052] v i，targ =K targ ·f targ (||p i -p targ ||)·min((r att -||P i -P targ ||), 0}·D i，targ

[0053] Among them, v i,targ is the flight speed of the UAV; min{(r att -||P i -P targ ||), 0} represents the difference between the attraction radius and the distance from the drone to the target position. When the distance from the drone to the target position is less than the attraction radius, it is 0; when the distance from the drone to the target position is greater than the attraction radius, it is the difference between the attraction radius and the distance from the drone to the target position, and it is a negative value; r att represents the attraction radius; is a direction vector that describes the direction from the target to the drone i.

[0054] The target tracking algorithm based on the variable gain strategy provided by the present invention can dynamically change the magnitude of the variable gain term, thereby adaptively varying the attraction speed. The speed of drones is not simply controlled by a proportional regulator. Traditional PID controllers are widely used, but because they only have a fixed gain term, a drawback is that if a drone is expected to reach a high speed at a distance to quickly approach a target, it cannot quickly adjust its speed to zero and stabilize upon approaching the target. Instead, it will experience oscillation due to the high speed. This can prevent the drone swarm from continuing to perform reconnaissance, strike, and other missions after completing target tracking. Conversely, to ensure that the drones quickly stabilize within a certain distance of the target, the speed of the drone swarm tracking the target is reduced. To address this drawback, the present invention uses a variable gain term instead of a fixed gain. In the speed control algorithm, the variable is the difference between the attraction radius and the distance value. The variable gain strategy primarily provides a variable gain term based on the distance between the drone and the target. The farther the drone is from the target, the larger the gain term, and the more pronounced the regulatory effect. The drone can quickly approach when the distance is far, and change the speed smoothly when the distance is close, so that it can quickly track the target and stabilize within a certain distance range of the target to avoid oscillation.

[0055] The above specific embodiments merely illustrate the design principles of the present invention. The shapes and names of the components described herein may vary and are not limiting. Therefore, those skilled in the art may modify or substitute equivalents for the technical solutions described in the above embodiments. Such modifications and substitutions, without departing from the inventive spirit and technical solutions of the present invention, shall fall within the scope of protection of the present invention.

Claims

1. A UAV cluster target tracking method based on variable gain strategy, characterized in that: In the flight control of a UAV cluster tracking a target, the fixed gain term of the UAV speed control is replaced by an independent variable gain term to adjust the flight speed of each UAV separately. The variable of the independent gain term is determined according to the difference between the attraction radius and the distance from the UAV to the target position; The attraction radius is the safe distance between the given drone and the target location; The variable gain term is the product of the adaptive control function and the fixed gain term; the variable gain term is expressed as K targ ·f targ (||p i -p targ ||); where K targ represents the fixed gain term, f targ (|| p ip targ ||)=||p i -p targ || represents the adaptive control function; P i represents the coordinate vector of UAV i, P targ Represents the coordinate vector of the target position, |||| represents the modulo operation; The flight speed of the UAV is determined by the independent gain term and the difference between the attraction radius and the distance from the UAV to the target position; the flight speed of the UAV is: v i，targ =K targ ·f targ (||p i -p targ ||)·min{(r att -||p i -p targ ||),0}·D i，targ Among them, v i,targ is the flight speed of the UAV; min{(r att -||p i -p targ ||), 0} represents the attraction radius r att The difference between the distance from the drone to the target position. When the distance from the drone to the target position is less than the attraction radius, it is 0; when the distance from the drone to the target position is greater than the attraction radius, it is the difference between the attraction radius and the distance from the drone to the target position, and it is a negative value. att represents the attraction radius; is a direction vector used to describe the direction from the target to the drone i.

2. A UAV cluster target tracking system based on variable gain strategy, characterized in that: include: Self-variable gain module, difference module, attraction radius given module and speed module; The variable gain module is used to provide the speed module with a variable gain term to replace the fixed gain term of the UAV speed control; The difference module is used to calculate the difference between the attraction radius and the distance from the UAV to the target position, and provide the difference as a variable of the independent gain term to the independent gain module; The attraction radius setting module is used to provide the attraction radius for the difference module; the attraction radius is a safe distance between the given drone and the target location; The speed module is used to adjust the flight speed of each UAV according to the independent gain item provided by the independent gain module; In the independent variable gain module, the independent variable gain term is obtained by calculating the product of the adaptive control function and the fixed gain term; The independent gain term is expressed as K targ ·f targ (||p i -p targ ||); where K targ represents the fixed gain term, f targ (||p i -p targ ||)=||P i -p targ || represents the adaptive control function; P i represents the coordinate vector of UAV i, P targ Represents the coordinate vector of the target position, |||| represents the modulo operation; In the speed module, the flight speed of the UAV is determined by the independent variable gain term and the difference between the attraction radius and the distance from the UAV to the target position; The flight speed of the UAV is: v i，targ =K targ ·f targ (||p i -p targ ||)·min{(r att -||P i -P targ ||),0}·D i，targ Among them, v i,targ is the flight speed of the UAV; mi{(r att -||P i -P targ ||), 0} represents the difference between the attraction radius and the distance from the drone to the target position. When the distance from the drone to the target position is less than the attraction radius, it is 0; when the distance from the drone to the target position is greater than the attraction radius, it is the difference between the attraction radius and the distance from the drone to the target position, and it is a negative value; r att represents the attraction radius; is a direction vector that describes the direction from the target to the drone i.

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