Time-varying group formation safety tracking control method for multiple unmanned aerial vehicles

Abstract

The invention discloses a multi-unmanned aerial vehicle-oriented time-varying group formation safety tracking control method, which comprises the following steps of: firstly, constructing a dynamic model of a multi-unmanned aerial vehicle system, determining a time-varying group formation safety tracking control problem, then constructing an unmanned aerial vehicle communication topology, and designing a formation reference signal and a time-varying group formation safety tracking controller; and determining whether a safety condition and a formation tracking feasibility condition are satisfied, calculating a formation compensation item and a feedback control gain, and finally applying the time-varying group formation safety tracking control method to the unmanned aerial vehicle to realize time-varying group formation safety tracking control. According to the method, a time-varying group formation safety tracking control scheme is designed for a multi-unmanned-aerial-vehicle system, the unmanned aerial vehicles are divided into a plurality of sub-groups under the scheme, the follower unmanned aerial vehicles of one sub-group can form a set formation, tracks of respective leaders are tracked under the condition that safety is guaranteed, and the unmanned aerial vehicle formation safety is improved. The predictability of motion planning is improved, and the problem of time-varying group formation safety tracking control of multiple unmanned aerial vehicles is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of multi - UAV systems, and particularly relates to a time - varying swarm formation safety tracking control method for multi - UAVs. Background Technique

[0002] In the past decade, the cooperative control of multi - UAV systems has received extensive attention. Among them, formation control is a typical cooperative control aiming to guide multi - UAV systems to form an ideal formation, and has been widely studied. The formation control technology of multi - UAVs is mainly divided into virtual structure, behavior - based, leader - follower, and consensus - based methods. Among them, the consensus - based method stands out due to its high robustness and scalability.

[0003] In the consensus - based formation control method, only adjacent communication between UAVs is required to achieve the desired formation. Currently, most research mainly focuses on the leaderless formation problem. However, in some practical applications, such as cooperative hunting, UAVs not only need to form a specific time - varying formation but also need to track a specific trajectory simultaneously. Therefore, the time - varying formation tracking control problem of multi - UAV systems has been widely studied. In addition, when dealing with complex tasks such as multi - target hunting and cooperative area search, multiple leader UAVs may be required to participate, and multiple UAVs are divided into multiple subgroups to perform different tasks. However, currently, most control methods consider that all UAVs belong to one subgroup and cannot be used to solve the multi - task cooperation problem. On the other hand, safety issues are particularly important during the formation process. UAVs need to prevent collisions with each other when performing tasks. Therefore, in addition to achieving ideal time - varying swarm formation tracking control, collision avoidance is of great significance for ensuring the safety and performance of large - scale multi - UAV systems. The commonly used collision avoidance strategies can be divided into artificial potential field method and geometric guidance method. The artificial potential field - based method cannot avoid the local minimum problem and cannot achieve asymptotic convergence of the position tracking error, which is particularly obvious in complex environments. In addition, the geometric guidance method has the disadvantage of high computational cost, which may be particularly demanding in real - time applications.

[0004] In summary, the time - varying swarm formation safety tracking control problem of multi - UAV systems has not been well solved. Summary of the Invention

[0005] To solve the above - mentioned technical problems, the present invention provides a time - varying swarm formation safety tracking control method for multi - UAVs, enabling UAVs in different subgroups to form a set formation and track the trajectories of their respective leaders while ensuring safety.

[0006] The technical solution adopted by the present invention is as follows: A time - varying swarm formation safety tracking control method for multi - UAVs, and the specific steps are as follows:

[0007] S1. Construct the dynamic model of the multi-UAV system and clarify the time-varying group formation safety tracking control problem;

[0008] S2. Based on step S1, construct the UAV communication topology and design the formation reference signal and the time-varying group formation safety tracking controller;

[0009] S3. Based on step S2, judge whether the safety conditions and the formation tracking feasibility conditions are satisfied;

[0010] S4. Based on step S3, calculate the formation compensation term and the feedback control gain;

[0011] S5. Based on steps S1 - S4, apply the time-varying group formation safety tracking control method to the UAVs to achieve time-varying group formation safety tracking control;

[0012] On the premise of satisfying the safety conditions and the formation tracking feasibility conditions, apply the time-varying group formation safety tracking controller designed in step S2 to the UAVs. Under the preset group division relationship, make the follower UAVs in the same subgroup form a set formation and track the trajectories of their respective leaders while ensuring safety, so as to achieve time-varying group formation safety tracking control for multi-UAVs.

[0013] Furthermore, step S1 is specifically as follows:

[0014] S11. Define the number of UAVs and the number of subgroups in the multi-UAV system;

[0015] Suppose there are M followers and N leaders in the multi-UAV system, and the system is divided into N subgroups, denoted as Each subgroup consists of one leader and g k followers, where Let and represent the sets of followers and leaders respectively.

[0016] Then define the subgroup of followers as Satisfying

[0017] S12. Construct the dynamic models of the follower UAVs and the leader UAVs;

[0018] First, establish the dynamic model of the i-th follower, and the expression is as follows:

[0019]

[0020] Where, represent the state and control input of the i-th follower respectively. t represents the running time of the system, Denote x i The first derivative of (t). and is the system matrix, and rank(B) = m. and represent the set of a-dimensional real vectors and the set of a×b real matrices respectively, and m, n represent any natural numbers greater than 0.

[0021] Then establish the dynamic model of the leader, and the expression is as follows:

[0022]

[0023] where represents the state of the leader, and u 0j represents the control input of the j-th leader, represents x 0j The first derivative of (t).

[0024] S13. Define the time-varying group formation safe tracking control problem;

[0025] Define the time-varying group formation safe tracking control problem, and the expression is as follows:

[0026]

[0027] where r min represents the minimum distance required to avoid collisions between follower UAVs, represents a piecewise continuously differentiable time-varying formation reference signal. When the conditions shown in Eqs. (3) and (4) are satisfied, it is said that the multi-UAV system achieves time-varying group formation safe tracking control.

[0028] Furthermore, the specific steps of step S2 are as follows:

[0029] S21. Construct the UAV communication topology and design the formation reference signal:

[0030] Set to represent the communication topology between follower UAVs, which consists of the node set the edge set ε f and the weighted adjacency matrix where if (j, i) ∈ ε f , then w ij > 0, otherwise, w ij = 0. If information can be transmitted from the leader UAV k to the follower UAV i, then w i0k > 0; otherwise, w i0k = 0. Then the Laplacian matrix expression of the system is as follows:

[0031]

[0032] Among them, if \(i\neq j\), then \(l\) ij \(=-w\) ij ; otherwise

[0033] Define a real diagonal matrix \(D = \text{diag}\{d_1, d_2, \cdots, d\) M \(\}\), \(d\) i \(> 0, i = 1, 2, \cdots, M\), let denote a positive definite matrix, and \(T\) denotes the matrix transpose.

[0034] For different subgroups Design a piecewise continuously differentiable time-varying formation reference signal \(h\) i (t). For any subgroup The formation reference signal \(h\) i (t) should satisfy the conditional expression as follows:

[0035] \(\min(\|h\) i (t)-h\) j (t)\|)=:\gamma\) k \(> r\) min \(> 0\ (6)\)

[0036] Among them, and \(i\neq j\); \(\gamma\) k represents the minimum value of the distance between any two UAVs within the subgroup, and \(r\) min represents the minimum distance required for the follower UAVs to avoid collision.

[0037] S22. Design a time-varying group formation safety tracking controller;

[0038] For any subgroup The construction expression of the time-varying group formation safety tracking controller is as follows:

[0039]

[0040] Among them,

[0041]

[0042] Among them, \(u\) i (t) represents the control input of the follower, \(\chi\) i represents the control gain, \(K_2\) represents the gain matrix, satisfying \(u\) 0k represents the control input of the \(k\)-th leader UAV, represents the upper bound of the control input. \(I\) m represents the \(m\)-dimensional identity matrix, represents the Kronecker product. \(K_1\) represents the feedback control gain, \(r\)i (t) represents the formation compensation term, and P is a positive definite matrix.

[0043] Further, the step S3 is specifically as follows:

[0044] S31. Determine whether the safety condition is satisfied;

[0045] Set e i (t) = x i (t) - x 0k (t) - h i (t), Then define the safety condition expression as follows:

[0046]

[0047] Among them, λ max (·) and λ min (·) respectively represent the maximum and minimum eigenvalues of a matrix,

[0048] If the initial tracking error of the subgroup of the multi-UAV system satisfies the safety condition formula (9), then continue to execute step S32; otherwise, return to step S1 and execute it again.

[0049] S32. Determine whether the formation tracking feasibility condition is satisfied;

[0050] If the rank of matrix B, rank(B) = m, then there exists a non-singular matrix satisfying and n > m.

[0051] Among them, is the left inverse matrix of B, is the matrix whose product with the B matrix is 0.

[0052] For each subgroup Calculate the formation tracking feasibility condition, and the expression is as follows:

[0053]

[0054] Among them, represents the first derivative of the time-varying formation reference signal h i (t). If the formation tracking feasibility condition formula (10) is satisfied, then continue to execute step S4; otherwise, return to step S1 and redesign the formation reference signal h i (t).

[0055] Further, the step S4 is specifically as follows:

[0056] First, calculate the formation compensation term, and the expression is as follows:

[0057]

[0058] Then, solve the algebraic Riccati equation to obtain the positive definite matrix P, and the expression is as follows:

[0059] PA + A T P - PBB T P + I n = 0 (12)

[0060] Among them, I n represents the n-dimensional identity matrix.

[0061] Finally, calculate the feedback control gain according to the positive definite matrix P, and the expression is as follows:

[0062] K1 = -γB T P (13)

[0063] Among them,

[0064] The beneficial effects of the present invention: The method of the present invention first constructs the dynamic model of the multi-UAV system and clarifies the time-varying formation safety tracking control problem, then constructs the UAV communication topology and designs the formation reference signal and the time-varying group formation safety tracking controller, and judges whether the safety conditions and the formation tracking feasibility conditions are satisfied, calculates the formation compensation term and the feedback control gain, and finally applies the time-varying group formation safety tracking control method to the UAVs to realize the time-varying group formation safety tracking control. The method of the present invention designs a time-varying group formation safety tracking control scheme for the multi-UAV system. Compared with the single-group formation control method, it considers the multi-group formation tracking control problem. In this scheme, the UAVs are divided into multiple subgroups. The follower UAVs in the same subgroup can form a preset time-varying formation and track the trajectories of their respective leaders while ensuring safety, avoiding collisions between UAVs while completing the time-varying group formation tracking control, generating smoother trajectories and improving the predictability of motion planning, and solving the time-varying group formation safety tracking control problem of multi-UAVs. Description of the Drawings

[0065] Figure 1 is a flowchart of a time-varying group formation safety tracking control method for multi-UAVs according to the present invention.

[0066] Figure 2 is the communication topology diagram of multi-UAVs in the embodiment of the present invention.

[0067] Figure 3 is the simulation result diagram of the state trajectories of multi-UAVs in the embodiment of the present invention. Detailed Embodiments

[0068] The method of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0069] As Figure 1 shown, the flowchart of a time-varying group formation safety tracking control method for multiple unmanned aerial vehicles according to the present invention is as follows:

[0070] S1. Construct the dynamic model of the multiple unmanned aerial vehicle system and clarify the time-varying formation safety tracking control problem;

[0071] S2. Based on step S1, construct the communication topology of the unmanned aerial vehicles and design the formation reference signal and the time-varying group formation safety tracking controller;

[0072] S3. Based on step S2, judge whether the safety condition and the formation tracking feasibility condition are satisfied;

[0073] S4. Based on step S3, calculate the formation compensation term and the feedback control gain;

[0074] S5. Based on steps S1 - S4, apply the time-varying group formation safety tracking control method to the unmanned aerial vehicles to achieve time-varying group formation safety tracking control;

[0075] On the premise of satisfying the safety condition and the formation tracking feasibility condition, apply the time-varying group formation safety tracking controller designed in step S2 to the unmanned aerial vehicles. Under the preset group division relationship, make the follower unmanned aerial vehicles in the same subgroup form a set formation and track the trajectories of their respective leaders while ensuring safety, so as to achieve time-varying group formation safety tracking control for multiple unmanned aerial vehicles.

[0076] In this embodiment, step S1 is specifically as follows:

[0077] S11. Define the number of unmanned aerial vehicles and the number of subgroups in the multiple unmanned aerial vehicle system;

[0078] Suppose there are M followers and N leaders in the multiple unmanned aerial vehicle system, and the system is divided into N subgroups, denoted as Each subgroup consists of one leader and g k followers, where Let and represent the sets of followers and leaders respectively.

[0079] Then define the subgroup of followers as Satisfying

[0080] S12. Construct the dynamic models of the follower unmanned aerial vehicles and the leader unmanned aerial vehicles;

[0081] First, establish the dynamic model of the \(i\)-th follower, and the expression is as follows:

[0082]

[0083] where, respectively represent the state and control input of the \(i\)-th follower. \(t\) represents the running time of the system, represents the first derivative of \(x\) i (t). and are system matrices, and \(\text{rank}(B)=m\). and respectively represent the set of real vectors of dimension \(a\) and the set of real matrices of dimension \(a\times b\), and \(m,n\) represent any natural numbers greater than 0.

[0084] Then, establish the dynamic model of the leader, and the expression is as follows:

[0085]

[0086] where, represents the state of the leader, and \(u\) 0j represents the control input of the \(j\)-th leader, represents the first derivative of \(x\) 0j (t).

[0087] S13. Define the time-varying formation safe tracking control problem;

[0088] To achieve time-varying group formation safe tracking control, define the time-varying formation safe tracking control problem, and the expression is as follows:

[0089]

[0090] where, \(r\) min represents the minimum distance required to avoid collisions between follower UAVs, represents the piecewise continuously differentiable time-varying formation reference signal. When the conditions shown in Eqs. (3) and (4) are satisfied, it is said that the multi-UAV system achieves time-varying group formation safe tracking control.

[0091] In this embodiment, the specific steps of step S2 are as follows:

[0092] S21. Construct the UAV communication topology and design the formation reference signal:

[0093] Set to represent the communication topology between follower UAVs, which consists of the node set the edge set \(\varepsilon\) f and the weighted adjacency matrix where if \((j,i)\in\varepsilon\)f , then w ij > 0, otherwise, w ij = 0. If the information can be transmitted from the leader UAV k to the follower UAV i, then w i0k > 0; otherwise, w i0k = 0. Then the Laplacian matrix expression of the system is as follows:

[0094]

[0095] Among them, If i≠j, then l ij = -w ij ; otherwise

[0096] Define a real diagonal matrix D = diag{d1, d2,..., d M},d i > 0, i = 1, 2,..., M, let represents a positive definite matrix, and T represents the matrix transpose.

[0097] For different subgroups Design a piecewise continuously differentiable time-varying formation reference signal h i (t). For any subgroup The formation reference signal h i (t) should satisfy the following conditional expression:

[0098] min(‖h i (t) - h j (t)‖) =: γ k > r min > 0 (6)

[0099] Among them, and i≠j; γ k represents the minimum value of the distance between any two UAVs within the subgroup, and r min represents the minimum distance required to avoid collisions between follower UAVs.

[0100] S22. Design a time-varying group formation safety tracking controller;

[0101] For any subgroup The construction expression of the time-varying group formation safety tracking controller is as follows:

[0102]

[0103] Among them,

[0104]

[0105] Among them, ui (t) represents the control input of the follower, χ i represents the control gain, K2 represents the gain matrix, satisfying u 0k represents the control input of the k-th leader UAV, represents the upper bound of the control input. I m represents the m-dimensional identity matrix, represents the Kronecker product. K1 represents the feedback control gain, r i (t) represents the formation compensation term, and P is a positive definite matrix.

[0106] In this embodiment, the step S3 is specifically as follows:

[0107] S31. Determine whether the safety condition is satisfied;

[0108] Set e i (t) = x i (t) - x 0k (t) - h i (t), Then the safety condition expression is defined as follows:

[0109]

[0110] where λ max (·) and λ min (·) respectively represent the maximum and minimum eigenvalues of a matrix,

[0111] If the initial tracking error of the subgroup of the multi-UAV system satisfies the safety condition formula (9), then continue to execute step S32; otherwise, return to step S1 and execute it again.

[0112] S32. Determine whether the formation tracking feasibility condition is satisfied;

[0113] If the rank of matrix B, rank(B) = m, then there exists a non-singular matrix satisfying and n > m.

[0114] where is the left inverse matrix of B, is the matrix whose product with the B matrix is 0.

[0115] For each subgroup Calculate the formation tracking feasibility condition, and the expression is as follows:

[0116]

[0117] where Denote the time-varying formation reference signal h i (t), the first derivative of which. If the formation tracking feasibility condition formula (10) is satisfied, then continue to execute step S4; otherwise, return to step S1 and redesign the formation reference signal h i (t).

[0118] In this embodiment, step S4 is specifically as follows:

[0119] First, calculate the formation compensation term, and the expression is as follows:

[0120]

[0121] Then, solve the algebraic Riccati equation to obtain the positive definite matrix P, and the expression is as follows:

[0122] PA + A T P - PBB T P + I n = 0 (12)

[0123] where, I n represents the n-dimensional identity matrix.

[0124] Finally, calculate the feedback control gain according to the positive definite matrix P, and the expression is as follows:

[0125] K1 = -γB T P (13)

[0126] where,

[0127] This embodiment further conducts simulation verification, where the communication topology diagram of the multi-UAV system is as Figure 2 shown. The multi-UAV system consists of 13 UAVs, which are divided into three groups. The leader UAV is represented by a yellow circle, and the follower UAVs are represented by green circles. That is, the first group consists of one leader and three followers, the second group also consists of one leader and three followers, and the third group consists of one leader and four followers.

[0128] The system matrices A and B of the UAV dynamics model are set with the following expressions:

[0129]

[0130] Then, the time-varying formation reference signals of each subgroup are set with the following expressions:

[0131]

[0132]

[0133] Thus, it is verified that the safety condition and feasibility condition of time-varying group formation tracking satisfy Eqs. (9) and (10). Then, the formation compensation term is calculated by Eq. (11). And in this embodiment, the control input of the leader UAV is u 01 = cos(t), u 02 = 1.5sin(t), u 03 = 0.05e -0.22t , and the parameter χ i = 2.

[0134] Then, the expressions of the positive definite matrix P and the gain matrix K1 are as follows:

[0135]

[0136] The state trajectory simulation results of multiple UAVs in this embodiment are as Figure 3 shown. It can be seen from the figure that each of the 10 follower UAVs will perform time-varying group formation tracking on the leader UAV according to the predefined grouping relationship.

[0137] In summary, through simulation experiments, the effectiveness of the theoretical results of the method of the present invention is verified. The method of the present invention introduces a distributed time-varying group formation tracking control protocol that only utilizes the relative information between adjacent UAVs, and proposes the safety condition and feasibility condition for the successful implementation of time-varying group formation tracking control of a multi-UAV system. Using the Lyapunov stability theory, the convergence of the time-varying group formation tracking error is verified, ensuring the safe realization of the ideal formation, solving the problem of time-varying group formation safety tracking control of multiple UAVs, enabling the UAVs in different subgroups to form a set formation, and tracking the trajectories of their respective leaders while ensuring safety.

[0138] Those of ordinary skill in the art will realize that the embodiments described herein are for helping the reader understand the principles of the present invention and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those of ordinary skill in the art can make various other specific deformations and combinations that do not deviate from the essence of the present invention based on these technical revelations disclosed in the present invention, and these deformations and combinations are still within the protection scope of the present invention.

Claims

1. A time-varying group formation safety tracking control method for multiple unmanned aerial vehicles, and the specific steps are as follows: S1. Construct the dynamic model of the multiple unmanned aerial vehicle system and clarify the time-varying group formation safety tracking control problem; S2. Based on step S1, construct the communication topology of the unmanned aerial vehicles and design the formation reference signal and the time-varying group formation safety tracking controller; S3. Based on step S2, judge whether the safety condition and the formation tracking feasibility condition are satisfied; S4. Based on step S3, calculate the formation compensation term and the feedback control gain; S5. Based on steps S1-S4, apply the time-varying group formation safety tracking control method to the unmanned aerial vehicles to achieve time-varying group formation safety tracking control; On the premise of satisfying the safety condition and the formation tracking feasibility condition, apply the time-varying group formation safety tracking controller designed in step S2 to the unmanned aerial vehicles. Under the preset group division relationship, make the follower unmanned aerial vehicles in the same subgroup form a set formation, and track the trajectories of their respective leaders while ensuring safety, so as to achieve time-varying group formation safety tracking control for multiple unmanned aerial vehicles.

2. The time-varying group formation safety tracking control method for multiple unmanned aerial vehicles according to claim 1, wherein The specific content of step S1 is as follows: S11. Define the number of unmanned aerial vehicles and the number of subgroups in the multiple unmanned aerial vehicle system; Suppose there are M followers and N leaders in a multi - UAV system, and the system is divided into N subgroups, denoted as Each subgroup consists of a leader and g k followers, where Let and represent the sets of followers and leaders respectively; Then define the subgroup of followers as satisfying S12. Construct the dynamic models of the follower unmanned aerial vehicles and the leader unmanned aerial vehicles; First, establish the dynamic model of the i-th follower, and the expression is as follows: wherein, respectively represent the state and control input of the i-th follower; t represents the running time of the system, represents the first derivative of x i (t); and are system matrices, and rank(B) = m; and respectively represent the set of a-dimensional real vectors and the set of a×b real matrices, and m, n represent any natural numbers greater than 0; Then, establish the dynamic model of the leader, and the expression is as follows: Among them, represents the state of the leader, u 0j represents the control input of the j-th leader, represents x 0j (the first derivative of t); S13. Clarify the time-varying group formation safety tracking control problem; Define the time-varying group formation safety tracking control problem, and the expression is as follows: where r min represents the minimum distance required to avoid collisions between follower drones, represents a piecewise continuously differentiable time-varying group formation reference signal.

3. A time-varying group formation safety tracking control method for multiple unmanned aerial vehicles according to claim 1, characterized in that The specific content of step S2 is as follows: S21. Construct the communication topology of the unmanned aerial vehicles and design the formation reference signal: Settings Represents the communication topology among follower UAVs, which consists of a set of nodes Set of edges ε f and a weighted adjacency matrix such that if (j,i) ∈ ε f , then w ij > 0, otherwise, w ij = 0; if information can be transmitted from the leader UAV k to the follower UAV i, then w i0k > 0; otherwise, w i0k = 0; then the expression of the Laplacian matrix of the system is as follows: Among them, If \(i\neq j\), then \(l\) ij \(=-w\) ij ; Otherwise Define a real diagonal matrix \(D = diag\{d_1, d_2, \cdots, d\) M \(\}\), \(d\) i \(> 0, i = 1, 2, \cdots, M\), let denote a positive definite matrix, and \(T\) denote the matrix transpose; For different subgroups Design a piecewise continuously differentiable time-varying group formation reference signal h i (t); for any subgroup The formation reference signal h i (t) should satisfy the following conditional expressions: min(‖h i (t)-h j (t)‖)=:γ k >r min >0 (6) wherein, and i≠j; γ k represents the minimum value of the distances between any two drones within the subgroup, and r min represents the minimum distance required to avoid collisions between the follower drones; S22. Design the time-varying group formation safety tracking controller; For any subgroup The construction expression of the time-varying group formation safety tracking controller is as follows: Wherein, Among them, u i (t) represents the control input of the follower, χ i represents the control gain, K2 represents the gain matrix, satisfying u 0k represents the control input of the k-th leader UAV, represents the upper bound of the control input; I m represents the m-dimensional identity matrix, represents the Kronecker product; K1 represents the feedback control gain, r i (t) represents the formation compensation term, and P is a positive definite matrix.

4. A time-varying group formation security tracking control method for multiple unmanned aerial vehicles according to claim 1, characterized in that, The specific content of step S3 is as follows: S31. Judge whether the safety condition is satisfied; Set e i (t) = x i (t) - x 0k (t) - h i (t), Then the safety condition expression is defined as follows: where λ max (·) and λ min (·) denote the maximum and minimum eigenvalues of a matrix, respectively, If the initial tracking error of the subgroup of the multiple unmanned aerial vehicle system satisfies the safety condition formula (9), then continue to execute step S32; otherwise, return to step S1 and execute it again; S32. Judge whether the formation tracking feasibility condition is satisfied; If the rank of matrix B, rank(B) = m, then there exists a non-singular matrix such that and n > m; Among them, is the left inverse matrix of B, is a matrix whose product with the B matrix is 0; For each subgroup Calculate the formation tracking feasibility condition, and the expression is as follows: Among them, represents the first derivative of the time-varying group formation reference signal h i (t); if the formation tracking feasibility condition formula (10) is satisfied, then continue to execute step S4, otherwise, return to step S1 and execute it again, and redesign the formation reference signal h i (t).

5. A time-varying group formation safety tracking control method for multiple unmanned aerial vehicles according to claim 1, characterized in that, The specific content of step S4 is as follows: First, calculate the formation compensation term, and the expression is as follows: Then, solve the algebraic Riccati equation to obtain the positive definite matrix P, and the expression is as follows: PA+A T P-PBB T P+I n =0 (12) Among them, I n represents an n-dimensional identity matrix; Finally, calculate the feedback control gain according to the positive definite matrix P, and the expression is as follows: K1 = -γB T P (13) Among them,

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