Multi-spacecraft attitude tracking preset performance control method and system under external disturbance

Abstract

The present invention provides a method and system for controlling preset performance of multi-spacecraft attitude tracking under external disturbances, the method comprising the following steps: establishing dynamic and kinematic models of a leader spacecraft and multiple follower spacecraft; setting a state observer in each follower spacecraft, estimating the attitude and angular velocity of the leader spacecraft through the state observer; establishing an error mathematical model of the state observer and the state of the follower spacecraft itself; setting an adaptive preset performance controller according to the error mathematical model, and keeping the error within the preset performance constraint function through the adaptive preset performance controller. The present invention can enable the multi-spacecraft system to achieve attitude consistency normally and quickly when receiving external disturbances, can realize true distributed control without global information; can keep the error coupling term in steady state within the prescribed preset performance function; has strong robustness, and can effectively deal with external disturbances.

Description

Technical Field

[0001] The present invention relates to the field of aerospace flight control technology, and in particular to a method and system for controlling preset performance of multi-spacecraft attitude tracking under external disturbance. Background Art

[0002] With the diversification of space missions, multi-spacecraft flight research has developed rapidly. As the basic technology of multi-spacecraft flight, attitude coordination is an important part of the current multi-spacecraft flight control. Multiple spacecraft individuals continuously adjust their attitudes to reach consistency through information transmission. In the actual space environment, spacecraft will be affected by unknown interference torques caused by gravity, thin atmospheric drag, solar radiation, etc., which greatly affect the control of spacecraft, making it impossible for sub-spacecraft to reach consistency, causing adverse effects on multi-spacecraft flight missions. Therefore, it is of great significance to study the control method of disturbed multi-spacecraft systems, and a more reliable control method is urgently needed.

[0003] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present application and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because they are described in the background technology section of the present application. Summary of the invention

[0004] The purpose of the present invention is to provide a preset performance control scheme for multi-spacecraft attitude tracking under external disturbances in response to the deficiencies in the above-mentioned background technology, so that the multi-spacecraft system can achieve attitude consistency normally and quickly when receiving external disturbances, avoiding adverse effects as much as possible.

[0005] In order to achieve the above object, the present invention provides a method for controlling the preset performance of multi-spacecraft attitude tracking under external disturbance, comprising the following steps:

[0006] S1, establish the dynamics and kinematics model of the leader spacecraft and multiple follower spacecraft;

[0007] S2, a state observer is set in each follower spacecraft to estimate the attitude and angular velocity of the leader spacecraft through the state observer;

[0008] S3, establish the error mathematical model of the state observer and the follower spacecraft's own state;

[0009] S4, setting an adaptive preset performance controller according to the error mathematical model, and using the adaptive preset performance controller to ensure that the error is always kept within the preset performance constraint function.

[0010] Furthermore, the kinematic and dynamic equations of the leader spacecraft in S1 based on attitude quaternions are as follows:

[0011]

[0012] ω0=Wv

[0013]

[0014] in is the leader's attitude unit quaternion, is the angular velocity of the leader, x × is a skew-symmetric matrix, which is specifically defined as follows:

[0015]

[0016] The kinematic and dynamic equations of the follower spacecraft based on attitude quaternion are as follows:

[0017]

[0018]

[0019]

[0020] in is the follower's attitude unit quaternion, is the angular velocity of the follower, is the positive definite inertia matrix, u i is the control torque, T di is the interference torque.

[0021] Furthermore, the i-th follower spacecraft in S2 estimates the state of the leader spacecraft through the following state observer:

[0022]

[0023]

[0024]

[0025]

[0026] in is the estimated value of the attitude quaternion, is the estimated value of angular velocity, μ1, μ2>0 are adjustable parameters, η0(t)=q0(t), ξ0(t)=ω0(t), is the set of neighbors of the i-th follower spacecraft.

[0027] Furthermore, the error between the state observer and the follower spacecraft in S3 is as follows:

[0028]

[0029]

[0030]

[0031] in is the attitude error, is the angular velocity error, k i >0 is an adjustable parameter, where

[0032] The error kinematics and error dynamics equations established in the i-th follower spacecraft are as follows:

[0033]

[0034]

[0035]

[0036] in

[0037]

[0038]

[0039]

[0040]

[0041] Furthermore, the preset performance function in S4 is:

[0042] -b iy ρ iy <z iy <ρ iy , ifz iy (0)>0

[0043] -ρ iy <z iy <b iy ρ iy , ifz iy (0)<0,y=1,2,3

[0044] ρ iy =(ρ iy 0-ρ iy∞ ) -ft +ρ iy∞

[0045] where biy ,f,ρ iy0 , ρ iy∞ All are adjustable parameters; f>0, ρ iy0 >ρ iy∞ >0;

[0046] Set the normalized error s iy =z iy / ρ iy , after the following conversion function T iy The conversion error x iy :

[0047]

[0048] Then the adaptive preset performance controller in the i-th follower spacecraft is as follows:

[0049] u i (t) = -g i x i -(κ i0 +κ i (t))z i

[0050]

[0051] where g i , κ i0 >0 is an adjustable parameter, p i (t) and Φ i is an intermediate variable, determined by the following two formulas:

[0052]

[0053] Φ i =1+||ω i ||+||ω i || 2

[0054] in, r i1 、r i2 、n i >0 are all adjustable parameters, p i (0)Known.

[0055] The present invention also provides a preset performance control system for multi-spacecraft attitude tracking under external disturbances, including a leader spacecraft, a follower spacecraft, a state observer and an adaptive preset performance controller. The state observer is located on the follower spacecraft and is used to estimate the attitude and angular velocity of the leader spacecraft. The adaptive preset performance controller controls the attitude of the follower spacecraft based on a mathematical model of the error between the state observer and the follower spacecraft's own state, so that the error always remains within a preset range.

[0056] The above scheme of the present invention has the following beneficial effects:

[0057] The preset performance control scheme for multi-spacecraft attitude tracking under external disturbance provided by the present invention designs a state observer in the follower spacecraft to estimate the state information of the leader spacecraft, and on this basis proposes an adaptive preset performance controller, which can enable the multi-spacecraft system to achieve attitude consistency normally and quickly when receiving external disturbances, and can realize true distributed control without global information; the adaptive preset performance controller can make the error coupling term in the steady state always remain within the prescribed preset performance function; it has strong robustness and can effectively cope with external disturbances, and the attitude error under the action of this controller is ultimately uniformly bounded;

[0058] Other beneficial effects of the present invention will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is a simulation topology diagram of the present invention;

[0060] Figure 2 is the error coupling term curve of follower spacecraft 1;

[0061] Figure 3 is the error coupling term curve of follower spacecraft 2;

[0062] Figure 4 is the error coupling term curve of follower spacecraft 3;

[0063] Figure 5 is the error coupling term curve of follower spacecraft 4. DETAILED DESCRIPTION

[0064] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0065] In the description of the present invention, for simplicity of explanation, the method or rule is depicted or described as a series of operations, and its purpose is neither to exhaustively list the experimental operations nor to limit the order of the experimental operations. For example, the experimental operations can be performed in various orders and / or simultaneously, and include other experimental operations that are not described again. In addition, the steps described are not all necessary for the methods and algorithms described herein. Those skilled in the art will recognize and understand that these methods and algorithms can be represented as a series of unrelated states through state diagrams or projects.

[0066] The present invention relates to the field of aerospace flight control technology. Attitude coordination, as the basic technology for multi-spacecraft flight, is an important part of current multi-spacecraft flight control. Multiple spacecraft individuals continuously adjust their own attitudes to reach consistency through information transmission. In an actual space environment, spacecraft will be affected by unknown interference torques caused by gravity, thin atmospheric resistance, solar radiation, etc., which greatly affect the control of the spacecraft, making it impossible for sub-spacecraft to reach consistency, causing adverse effects on multi-spacecraft flight missions. It is of great significance to study the control method of a disturbed multi-spacecraft system. Based on this, embodiment 1 of the present invention provides a multi-spacecraft attitude tracking preset performance control method under external disturbance, aiming to solve the above problems.

[0067] The method specifically comprises the following steps:

[0068] S1: Set up a multi-spacecraft system consisting of a virtual leader spacecraft and multiple follower spacecraft as the research object, regard the spacecraft as a rigid body, and establish the spacecraft dynamics and kinematics model.

[0069] Among them, the kinematic and dynamic equations of the leader spacecraft based on attitude quaternion are as follows:

[0070]

[0071] ω0=Wv

[0072]

[0073] in is the leader's attitude unit quaternion, is the angular velocity of the leader, x × is a skew-symmetric matrix, which is specifically defined as follows:

[0074]

[0075] The kinematic and dynamic equations of the follower spacecraft based on attitude quaternion are as follows:

[0076]

[0077]

[0078]

[0079] in is the attitude unit quaternion of follower i, is the angular velocity of the follower, is the positive definite inertia matrix, u i To control the torque, the spacecraft attitude is controlled by the controller, T di is the disturbance torque, such as the unknown disturbance torque caused by gravity, thin atmospheric drag, solar radiation, etc.

[0080] S2: A state observer is set in each follower spacecraft to estimate the attitude and angular velocity of the leader spacecraft.

[0081] In this embodiment, specifically Figure 1 As shown, a leader spacecraft (numbered 0) and four follower spacecraft (numbered 1-4) are used as an example for explanation. The i-th (i=1-4) follower spacecraft has the following state observer to estimate the state of the leader spacecraft:

[0082]

[0083]

[0084]

[0085]

[0086] in is the estimated value of the attitude quaternion, is the estimated value of angular velocity, μ1, μ2>0 are adjustable parameters, η0(t)=q0(t), ξ0(t)=ω0(t), is the set of neighbors of the i-th follower spacecraft.

[0087] Specifically, follower spacecraft 1 can directly receive the attitude information of the leader spacecraft, so η0(t) = q0(t), ξ0(t) = ω0(t) in its own state observer, and calculates its own state observer information η1(t) and ξ1(t) based on this information and the above dynamic equations, and at the same time sends its own state observer information η1(t) and ξ1(t) to follower spacecraft 2 and follower spacecraft 4. Follower spacecraft 2 can receive the observer information η1(t) and ξ1(t) of follower spacecraft 1, which is used to calculate its own state observer information η2(t) and ξ2(t) and send it to follower spacecraft 3 and follower spacecraft 4; similarly, follower spacecraft 3 can receive the observer information η2(t) and ξ2(t) of follower spacecraft 2, which is used to calculate its own state observer information η3(t) and ξ3(t); similarly, follower spacecraft 4 can receive the observer information η1(t), η2(t), ξ1(t) and ξ2(t) of follower spacecraft 1 and follower spacecraft 2, which is used to calculate its own state observer information η4(t) and ξ4(t).

[0088] S3: Establish a mathematical model of the error between the state observer and the state of the follower spacecraft itself in the i-th follower spacecraft.

[0089] Among them, the error between the state observer and the follower spacecraft is as follows:

[0090]

[0091]

[0092]

[0093] in is the attitude error, is the angular velocity error, k i >0 is an adjustable parameter, where

[0094] The error kinematics and error dynamics equations established in the i-th follower spacecraft according to the errors defined above are as follows:

[0095]

[0096]

[0097]

[0098] in

[0099]

[0100]

[0101]

[0102]

[0103] S4: An adaptive preset performance controller is set according to the error mathematical model. Through the adaptive preset performance controller, the error can always be kept within the preset performance constraint function.

[0104] Specifically, the preset performance function is:

[0105] -b iy ρ iy <z iy <ρ iy , ifz iy (0)>0

[0106] -ρ iy <z iy <b iy ρ iy , ifz iy (0)<0,y=1,2,3

[0107] ρ iy =(ρ iy 0-ρ iy∞ ) -ft +ρ iy∞

[0108] where b iy ,f,ρ iy0 , ρ iy∞ All are adjustable parameters; f>0, ρ iy0 >ρ iy∞ >0.

[0109] Set the normalized error s iy =z iy / ρ iy , after the following conversion function T iy The conversion error x iy :

[0110]

[0111] Therefore the adaptive preset performance controller is set as follows:

[0112] u i (t) = -g i x i -(κ i0 +κ i (t))z i

[0113]

[0114] where g i , κ i0 >0 is an adjustable parameter, p i (t), Φ i is an intermediate variable, given by the following two formulas:

[0115]

[0116] φ i =1+||ω i ||+||ω i || 2

[0117] Among them, r i1 、r i2 、n i >0 are all adjustable parameters, p i (0) Known,

[0118] The method provided in this embodiment is to solve the preset performance control problem of attitude tracking of a multi-spacecraft system under a directed communication topology structure of a directed spanning tree with the leader spacecraft as the root. A state observer is designed in the follower spacecraft to estimate the state information of the leader spacecraft, and on this basis, an adaptive preset performance controller is proposed, which can enable the multi-spacecraft system to achieve attitude consistency normally and quickly when receiving external disturbances.

[0119] The method provided in this embodiment is further described below through a specific example, and a simulation verification is performed using Matlab software. The specific parameters of the multi-spacecraft attitude tracking preset performance control system are set as follows:

[0120] Select the initial state of the leader spacecraft q0(0) = col(sin1.5, 0, 0, cos1.5), v0(0) = col(1, 0, 1, 0, 1, 0, 1), and the matrices W and S are selected as follows:

[0121]

[0122]

[0123] Select four follower spacecraft, and the initial values ​​of attitude and angular velocity are:

[0124] q1(0)=col(sin2,0,0,cos2),ω1(0)=col(0,1,0)

[0125] q2(0)=col(0,sin0.6,0,cos0.6),ω2(0)=col(0,0,0.6)

[0126] q3(0)=col(0,sin3,0,cos3),ω3(0)=col(0,0.2,0)

[0127] q4(0)=col(0,0,sin3.5,cos3.5),ω4(0)=col(0.4,0,0)

[0128] The inertia matrices of the four follower spacecraft are selected as follows:

[0129]

[0130] The external disturbances to the follower spacecraft are as follows:

[0131] T di =(0.2+0.1‖ω i ‖ 2 )col(sin0.5t,sin0.5t,cos0.5t),i=1,2,3,4

[0132] Select the adjustable parameters μ1=μ2=10 in the four state observers, and the initial value is:

[0133] η1(0)=col(0.3,0,0,0),ξ1(0)=col(0,0.2,0,0,0.2,0,0)

[0134] η2(0)=col(0,0,1,0),ξ2(0)=col(0,0,0,0,0.5,0,0.5)

[0135] η3(0)=col(0,1.2,0,0),ξ3(0)=col(1,0,0,0,0,0,1)

[0136] η4(0)=col(0,0,0,0.8),ξ4(0)=col(0,0.8,0,0,0,0,0.8)

[0137] Select the adjustable parameter b in the preset performance function iy =1.5,ρ iy0 =4,ρ iy∞ =0.1, f=-1, i=1,2,3,4, y=1,2,3.

[0138] Select the adaptive preset performance controller adjustable parameter g i =20,κ i0 =5,κ i =2, r i1=0.3, r i2 =0.01, p i (0) = 0.1, n i =2.

[0139] Through Matlab simulation calculation, the simulation results are as follows Figure 2-Figure 5 As shown, it can be seen that the multi-spacecraft system can quickly achieve attitude consistency when receiving external disturbances, thereby achieving the technical purpose of the present invention.

[0140] Embodiment 2:

[0141] Embodiment 2 of the present invention provides a preset performance control system for attitude tracking of multiple spacecraft under external disturbances, including a leader spacecraft, a follower spacecraft, a state observer and an adaptive preset performance controller. The state observer is located on the follower spacecraft and is used to estimate the attitude and angular velocity of the leader spacecraft. The adaptive preset performance controller controls the attitude of the follower spacecraft based on a mathematical model of the error between the state observer and the state of the follower spacecraft itself, so that the error always remains within a preset range.

[0142] The adaptive preset performance controller in this system can enable the multi-spacecraft system to achieve attitude consistency normally and quickly when receiving external disturbances, and can realize true distributed control without the need for global information; the adaptive preset performance controller can make the error coupling terms in the steady state always remain within the specified preset performance function; it has strong robustness and can effectively respond to external disturbances. The attitude error under the action of this controller is ultimately consistently bounded.

[0143] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for controlling the preset performance of multi-spacecraft attitude tracking under external disturbances, characterized in that: The steps include: S1, establish the dynamics and kinematics model of the leader spacecraft and multiple follower spacecraft; S2, a state observer is set in each follower spacecraft to estimate the attitude and angular velocity of the leader spacecraft through the state observer; S3, establish the error mathematical model of the state observer and the follower spacecraft's own state; S4, setting an adaptive preset performance controller according to the error mathematical model, and making the error always remain within the preset performance constraint function through the adaptive preset performance controller; The kinematic and dynamic equations of the leader spacecraft in S1 based on attitude quaternions are as follows: ω0=Wv in is the leader's attitude unit quaternion, is the angular velocity of the leader, x × is a skew-symmetric matrix, which is specifically defined as follows: The kinematic and dynamic equations of the follower spacecraft based on attitude quaternion are as follows: in is the follower's attitude unit quaternion, is the angular velocity of the follower, is the positive definite inertia matrix, u i is the control torque, T di is the interference torque.

2. The method for controlling the preset performance of multi-spacecraft attitude tracking under external disturbance according to claim 1, characterized in that: The i-th follower spacecraft in S2 estimates the state of the leader spacecraft through the following state observer: in is the estimated value of the attitude quaternion, is the estimated value of angular velocity, μ1, μ2>0 are adjustable parameters, η0(t)=q0(t), ξ0(t)=ω0(t), is the set of neighbors of the i-th follower spacecraft.

3. The method for controlling the preset performance of multi-spacecraft attitude tracking under external disturbance according to claim 2, characterized in that: The error between the state observer and the follower spacecraft in S3 is as follows: in is the attitude error, is the angular velocity error, k i >0 is an adjustable parameter, where The error kinematics and error dynamics equations established in the i-th follower spacecraft are as follows: in 4. The method for controlling the preset performance of multi-spacecraft attitude tracking under external disturbance according to claim 3, characterized in that: The preset performance functions in S4 are: -b iy ρ iy <z iy <ρ iy ,ifz iy (0)>0 -r iy <z iy iy r iy ,ifz iy (0)<0,y=1,2,3​ r iy =(ρ iy0 -r iy∞ )e -ft +r iy∞ where b iy ,f,ρ iy0 , ρ iy∞ are all adjustable parameters, f>0, ρ iy0 >ρ iy∞ >0; Set the normalized error s iy =z iy / ρ iy , after the following conversion function T iy The conversion error x iy : Then the adaptive preset performance controller in the i-th follower spacecraft is as follows: u i (t)=-g i x i -(k i0 +k i (t))z i where g i , κ i0 >0 is an adjustable parameter, p i (t) and Φ i The dynamics are as follows: F i =1+||ω i ||+||ω i || 2 Among them, r i1 、r i2 、n i >0 are all adjustable parameters.

5. A multi-spacecraft attitude tracking preset performance control system under external disturbance, using the multi-spacecraft attitude tracking preset performance control method under external disturbance as claimed in any one of claims 1 to 4, characterized in that: It includes a leader spacecraft, a follower spacecraft, a state observer and an adaptive preset performance controller. The state observer is located on the follower spacecraft and is used to estimate the attitude and angular velocity of the leader spacecraft. The adaptive preset performance controller controls the attitude of the follower spacecraft based on a mathematical model of the error between the state observer and the state of the follower spacecraft itself, so that the error is always kept within a preset range.

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