Thruster fault identification method and device based on sliding mode observer

Abstract

The invention discloses a thruster fault identification method and device based on a sliding mode observer. The method comprises the following steps: designing a sliding-mode observer based on a spacecraft dynamics model; calculating the real triaxial angular velocity of the spacecraft in the current control period based on the gyro output of the spacecraft system; estimating the estimated triaxial angular velocity of the spacecraft in the current control period based on the sliding-mode observer; determining a residual function of the current control period based on the real triaxial angular velocity and the estimated triaxial angular velocity; on the basis of the relation between the residual function and a preset threshold value, whether a thruster fault exists in the current control period or not is determined; and if yes, calculating a thruster fault matrix estimated in the current control period based on a residual function, calculating an included angle between the thruster fault matrix estimated in the current control period and each column in a predetermined thruster fault matrix, and determining the thruster corresponding to the column with the minimum included angle as a fault thruster. According to the application, the fault can be positioned to each thruster.

Description

Technical Field

[0001] The present invention relates to the technical field of fault diagnosis, and in particular to a thruster fault identification method and device based on a sliding mode observer. Background Art

[0002] As the actuator of the spacecraft's orbit and attitude control system, the thrusters are responsible for many functions such as orbit and attitude control, orbit and attitude maneuvers, and position maintenance. Once a failure occurs, it will have a serious impact on the completion of the spacecraft's mission.

[0003] At present, the relevant technology mainly uses the cumulative jet time of the thruster to determine the state of the thruster, that is, when a thruster frequently jets, it is considered that the thruster may have a fault. However, the fault identification result is relatively rough, and it is impossible to determine which thruster has a fault. Therefore, the fault can only be handled by switching the entire group of thrusters, resulting in a serious waste of on-board resources.

[0004] Therefore, there is an urgent need for a thruster fault identification method and device based on a sliding mode observer to solve the above problems. Summary of the invention

[0005] The present invention provides a thruster fault identification method and device based on a sliding mode observer, which can locate the fault in each thruster. The technical solution is as follows:

[0006] On the one hand, a thruster fault identification method based on a sliding mode observer is provided, the method comprising:

[0007] Based on the spacecraft dynamics model, a sliding mode observer is designed; the sliding mode observer is used to estimate the three-axis angular velocity of the spacecraft;

[0008] Based on the gyro output of the spacecraft system, the real three-axis angular velocity of the spacecraft in the current control cycle is calculated;

[0009] estimating the three-axis angular velocity of the spacecraft in the current control period based on the sliding mode observer;

[0010] Determining a residual function of a current control cycle based on the actual three-axis angular velocity and the estimated three-axis angular velocity;

[0011] Based on the relationship between the residual function and the preset threshold, it is determined whether there is a thruster fault in the current control cycle; if there is, a thruster fault matrix estimated in the current control cycle is calculated based on the residual function, and an angle between the thruster fault matrix estimated in the current control cycle and each column in a predetermined thruster fault matrix is ​​calculated, and a thruster corresponding to a column with the smallest angle is determined as a faulty thruster.

[0012] On the other hand, a thruster fault identification device based on a sliding mode observer is provided, the device comprising:

[0013] A design unit is used to design a sliding mode observer based on a spacecraft dynamics model; the sliding mode observer is used to estimate the estimated three-axis angular velocity of the spacecraft;

[0014] A calculation unit, used for calculating the true three-axis angular velocity of the spacecraft in the current control period based on the gyro output of the spacecraft system;

[0015] an estimating unit, configured to estimate the estimated three-axis angular velocity of the spacecraft in the current control period based on the sliding mode observer;

[0016] A first determining unit, configured to determine a residual function of a current control cycle based on the true three-axis angular velocity and the estimated three-axis angular velocity;

[0017] a second determination unit, configured to determine whether there is a thruster fault in a current control cycle based on a relationship between the residual function and a preset threshold;

[0018] The third determination unit is used to calculate the thruster fault matrix estimated in the current control cycle based on the residual function when there is a thruster fault, and calculate the angle between the thruster fault matrix estimated in the current control cycle and each column in the predetermined thruster fault matrix, and determine the thruster corresponding to the column with the smallest angle as the faulty thruster.

[0019] On the other hand, a computer-readable storage medium is provided, wherein a computer program is stored in the storage medium, and when the computer program is executed by a processor, the steps of the thruster fault identification method based on the sliding mode observer are implemented.

[0020] On the other hand, a computer program product is provided, comprising a computer program, wherein when the computer program is executed by a processor, the steps of the thruster fault identification method based on the sliding mode observer are implemented.

[0021] The embodiment of the present invention provides a thruster fault identification method based on a sliding mode observer. By designing a sliding mode observer, the three-axis angular velocity of a spacecraft can be estimated. Then, by comparing and analyzing the gyro output and the sliding mode observer output, a residual function is obtained. Then, based on the relationship between the residual function and the threshold, it is determined whether there is a thruster fault. If so, the estimated thruster fault matrix is ​​determined. Finally, based on the angle between the estimated thruster fault matrix and each column in the predetermined thruster fault matrix, the specific position of the faulty thruster is determined. It can be seen that the present application can realize thruster fault detection and accurate positioning, and provide a basis for improving the accuracy of thruster fault diagnosis and refining fault handling strategies. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 is a flow chart of a thruster fault identification method based on a sliding mode observer provided by an embodiment of the present invention;

[0024] Figure 2 It is a structural diagram of a thruster fault identification device based on a sliding mode observer provided by one embodiment of the present invention;

[0025] Figure 3 It is a hardware architecture diagram of a computer device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all 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.

[0027] The specific implementation of the above concept is described below.

[0028] Please refer to Figure 1 , an embodiment of the present invention provides a thruster fault identification method based on a sliding mode observer, the method comprising:

[0029] Step 100, designing a sliding mode observer based on a spacecraft dynamics model; the sliding mode observer is used to estimate the three-axis angular velocity of the spacecraft;

[0030] Step 102, calculating the true three-axis angular velocity of the spacecraft in the current control period based on the gyro output of the spacecraft system;

[0031] Step 104, estimating the three-axis angular velocity of the spacecraft in the current control period based on the sliding mode observer;

[0032] Step 106, determining a residual function of a current control cycle based on the actual three-axis angular velocity and the estimated three-axis angular velocity;

[0033] Step 108, determining whether there is a thruster fault in the current control cycle based on the relationship between the residual function and a preset threshold;

[0034] Step 110, when there is a thruster fault, the thruster fault matrix estimated in the current control cycle is calculated based on the residual function, and the angle between the thruster fault matrix estimated in the current control cycle and each column in the predetermined thruster fault matrix is ​​calculated, and the thruster corresponding to the column with the smallest angle is determined as the faulty thruster.

[0035] In this embodiment, by designing a sliding mode observer, the three-axis angular velocity of the spacecraft can be estimated. Then, by comparing and analyzing the gyro output and the sliding mode observer output, a residual function is obtained. Then, based on the relationship between the residual function and the threshold, it is determined whether there is a thruster fault. If so, the estimated thruster fault matrix is ​​determined. Finally, based on the angle between the estimated thruster fault matrix and each column in the predetermined thruster fault matrix, the specific position of the faulty thruster is determined. It can be seen that the present application can realize thruster fault detection and accurate positioning, and provide a basis for improving the accuracy of thruster fault diagnosis and refining fault handling strategies.

[0036] Described below Figure 1 How the various steps are performed.

[0037] First, for step 100:

[0038] The following spacecraft dynamics model is used:

[0039]

[0040] in,

[0041] Based on the above spacecraft dynamics model, the following sliding mode observer model is designed:

[0042]

[0043] Where I is the moment of inertia; U = diag(T1, T2, T3) is the desired output torque matrix, T1, T2 and T3 are the desired output torques of the spacecraft on the x-axis, y-axis and z-axis respectively; ω = [ω1 ω2 ω3] T is the true three-axis angular velocity of the spacecraft, ω1, ω2 and ω3 are the angular velocities of the x-axis, y-axis and z-axis respectively; is the differential of ω; ω x is the antisymmetric matrix of ω; D is the thruster fault matrix, Indicates that D is 3×N thrust The real matrix, N thrust is the number of thrusters; ft,i Indicates the failure of thruster i, i = 1, 2, ... N thrust ; d is the external interference torque, satisfying is the maximum boundary of the external disturbance torque d; ||·|| represents the norm; is the estimated thruster fault matrix; L is a positive definite matrix, L∈R 3×3 ; The estimated three-axis angular velocity of the spacecraft output by the sliding mode observer; for The differential of for The antisymmetric matrix of .

[0044] By designing the above sliding mode observer, the three-axis angular velocity of the spacecraft can be estimated according to its output.

[0045] With respect to step 102, based on the gyro output of the spacecraft system, the actual three-axis angular velocity of the spacecraft in the current control cycle is calculated, including:

[0046] Determine whether the gyroscope is a gyroscope with three axes orthogonally installed;

[0047] If yes, the three-axis angular velocity output by the gyroscope is used as the three-axis angular velocity of the spacecraft;

[0048] If not, determine the three-axis angular velocity of the spacecraft based on the following formula;

[0049]

[0050] Where ω is the true three-axis angular velocity of the spacecraft, ω1, ω2 and ω3 are the angular velocities of the x-axis, y-axis and z-axis respectively; V is the installation matrix of the gyroscope; g1, g2 to g s are the output angular velocities of the gyroscopes, and s is the number of gyroscopes.

[0051] In this step, all gyroscopes are fault-free gyroscopes and can accurately output angular velocity.

[0052] For step 106, the calculation formula of the residual function is:

[0053]

[0054] Where r(t) is the residual function at time t, ω(t) is the true three-axis angular velocity of the spacecraft at time t; is the estimated three-axis angular velocity of the spacecraft output by the sliding mode observer at time t.

[0055] In this step, the residual function can be obtained by jointly solving the calculation formula of the spacecraft dynamics model and the sliding mode observer.

[0056] With respect to step 108, determining whether there is a thruster fault in the current control cycle based on the relationship between the residual function and the preset threshold value includes:

[0057] Determine whether the residual function is less than a preset threshold;

[0058] If so, it is determined that there is no thruster fault in the current control cycle;

[0059] If not, it is determined that there is a thruster fault in the current control cycle.

[0060] In some implementations, the preset threshold at each moment is determined using the following formula:

[0061]

[0062] In the formula, J th (t) is the preset threshold at time t, which is used to represent the upper bound of the residual evaluation function; t is the time; k and λ are positive numbers, and the two parameters satisfy ||e Λt ||≤ke -λt , Λ is a stable matrix; γ1 is the Lipschitz constant with respect to ω, satisfying ε is a constant, satisfying is; I is the moment of inertia; is the maximum boundary of the external interference torque d.

[0063] In this step, the preset threshold is a time-varying threshold, and different thresholds are used at different times, which are functions of time. By using a time-varying threshold, the influence of external interference can be fully considered, thereby reducing the missed alarm rate and false alarm rate of thruster fault detection.

[0064] In some implementations, the thruster fault matrix estimated for each control cycle is determined using the following formula:

[0065]

[0066] In the formula, and are the thruster fault matrices estimated at time t and time t-1; γ and δ s is a positive real number; r(t) is the residual function at time t; U = diag(T1, T2, T3) is the expected output torque matrix, T1, T2 and T3 are the expected output torques of the spacecraft x-axis, y-axis and z-axis respectively; P is a symmetric matrix, and P satisfies the following conditions:

[0067]

[0068] in, Γ=-I -1 L;

[0069] Ω1 and Γ are both intermediate parameters; L is a positive definite matrix, L∈R 3×3 .

[0070] In this step, for any control cycle, as long as the residual function of the control cycle and the thruster fault matrix estimated in the previous control cycle are obtained, the thruster fault matrix estimated in the control cycle can be calculated.

[0071] Finally, in some implementations, the following formula is used to determine the failed thruster:

[0072]

[0073] In the formula, i f is the thruster serial number of the failure; d i is the i-th column of the thruster fault matrix D; is the estimated thruster fault matrix; N thrust is the number of thrusters; norm(·) means modulus; dot(·) means dot multiplication operation.

[0074] In this step, the smaller the angle between the estimated thruster fault matrix and the corresponding column in the predetermined thruster fault matrix, the better the calculated i f The larger the value, the greater the possibility of failure. f The thruster corresponding to the largest column is determined to be the faulty thruster.

[0075] like Figure 2 , Figure 3 As shown, an embodiment of the present invention provides a thruster fault identification device based on a sliding mode observer. The device embodiment can be implemented by software, or by hardware or a combination of software and hardware. From the hardware level, Figure 2 As shown, it is a hardware architecture diagram of a computing device where a thruster fault identification device based on a sliding mode observer provided by an embodiment of the present invention is located. Figure 2 In addition to the processor, memory, network interface, and non-volatile memory shown in the figure, the computing device in which the device is located in the embodiment may also generally include other hardware, such as a forwarding chip responsible for processing messages, etc. Taking software implementation as an example, Figure 3 As shown, as a device in a logical sense, the CPU of the computing device in which it is located reads the corresponding computer program in the non-volatile memory into the internal memory and runs it.

[0076] Please refer to Figure 3 The embodiment of the present invention provides a thruster fault identification device based on a sliding mode observer, the device comprising:

[0077] The design unit 300 is used to design a sliding mode observer based on a spacecraft dynamics model; the sliding mode observer is used to estimate the three-axis angular velocity of the spacecraft;

[0078] A calculation unit 302 is used to calculate the real three-axis angular velocity of the spacecraft in the current control period based on the gyro output of the spacecraft system;

[0079] An estimation unit 304 is used to estimate the estimated three-axis angular velocity of the spacecraft in the current control period based on a sliding mode observer;

[0080] A first determining unit 306, configured to determine a residual function of a current control cycle based on the actual three-axis angular velocity and the estimated three-axis angular velocity;

[0081] A second determination unit 308, configured to determine whether there is a thruster fault in the current control cycle based on a relationship between the residual function and a preset threshold;

[0082] The third determining unit 310 is used to calculate the thruster fault matrix estimated in the current control cycle based on the residual function when there is a thruster fault, and calculate the angle between the thruster fault matrix estimated in the current control cycle and each column in the predetermined thruster fault matrix, and determine the thruster corresponding to the column with the smallest angle as the faulty thruster.

[0083] In some embodiments, the spacecraft dynamics model is:

[0084]

[0085] in,

[0086] The sliding mode observer satisfies the following formula:

[0087]

[0088] Where I is the moment of inertia; U = diag(T1, T2, T3) is the desired output torque matrix, T1, T2 and T3 are the desired output torques of the spacecraft on the x-axis, y-axis and z-axis respectively; ω = [ω1 ω2 ω3] T is the true three-axis angular velocity of the spacecraft, ω1, ω2 and ω3 are the angular velocities of the x-axis, y-axis and z-axis respectively; is the differential of ω; ω x is the antisymmetric matrix of ω; D is the thruster fault matrix, Indicates that D is 3×N thrust The real matrix, N thrust is the number of thrusters; f t,i Indicates the failure of thruster i, i = 1, 2, ... N thrust; d is the external interference torque, satisfying is the maximum boundary of the external disturbance torque d; ||·|| represents the norm; is the estimated thruster fault matrix; L is a positive definite matrix, L∈R 3×3 ; The estimated three-axis angular velocity of the spacecraft output by the sliding mode observer; for The differential of for The antisymmetric matrix of .

[0089] In some implementations, the computing unit 302 is configured to perform the following operations:

[0090] Determine whether the gyroscope is a gyroscope with three axes orthogonally installed;

[0091] If yes, the three-axis angular velocity output by the gyroscope is used as the three-axis angular velocity of the spacecraft;

[0092] If not, determine the three-axis angular velocity of the spacecraft based on the following formula;

[0093]

[0094] Where ω is the true three-axis angular velocity of the spacecraft, ω1, ω2 and ω3 are the angular velocities of the x-axis, y-axis and z-axis respectively; V is the installation matrix of the gyroscope; g1, g2 to g s are the output angular velocities of the gyroscopes, and s is the number of gyroscopes.

[0095] In some embodiments, the residual function is calculated as:

[0096]

[0097] Where r(t) is the residual function at time t, ω(t) is the true three-axis angular velocity of the spacecraft; It is the estimated three-axis angular velocity of the spacecraft output by the sliding mode observer.

[0098] In some implementations, determining whether there is a thruster fault in the current control cycle based on the relationship between the residual function and a preset threshold value includes:

[0099] Determine whether the residual function is less than a preset threshold;

[0100] If so, it is determined that there is no thruster fault in the current control cycle;

[0101] If not, it is determined that there is a thruster fault in the current control cycle.

[0102] In some implementations, the preset threshold is a time-varying threshold, and the preset threshold at each moment is determined using the following formula:

[0103]

[0104] In the formula, J th (t) is the preset threshold at time t, which is used to represent the upper bound of the residual evaluation function; t is the time; k and λ are positive numbers, and the two parameters satisfy ||e Λt ||≤ke -λt , Λ is a stable matrix; γ1 is the Lipschitz constant with respect to ω, satisfying ε is a constant, satisfying is; I is the moment of inertia; is the maximum boundary of the external interference torque d.

[0105] In some implementations, the thruster fault matrix estimated for each control cycle is determined using the following formula:

[0106]

[0107] In the formula, and are the thruster fault matrices estimated at time t and time t-1; γ and δ s is a positive real number; r(t) is the residual function at time t; U = diag(T1, T2, T3) is the expected output torque matrix, T1, T2 and T3 are the expected output torques of the spacecraft x-axis, y-axis and z-axis respectively; P is a symmetric matrix, and P satisfies the following conditions:

[0108]

[0109] in,

[0110] Γ=-I -1 L;

[0111] Ω1 and Γ are both intermediate parameters; L is a positive definite matrix, L∈R 3×3 .

[0112] In some embodiments, the following formula is used to determine the failed thruster:

[0113]

[0114] In the formula, i f is the thruster serial number of the failure; d i is the i-th column of the thruster fault matrix D; is the estimated thruster fault matrix; N thrustis the number of thrusters; norm(·) means modulus; dot(·) means dot multiplication operation.

[0115] It should be noted that: the thruster fault identification device based on the sliding mode observer provided in the above embodiment is only illustrated by the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. In addition, the thruster fault identification device based on the sliding mode observer provided in the above embodiment and the thruster fault identification method embodiment based on the sliding mode observer belong to the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here.

[0116] The embodiment of the present application also provides a computer device, please refer to Figure 3 The computer device includes a processor and a memory, wherein at least one instruction, at least one program, a code set or an instruction set is stored in the memory, and the at least one instruction, at least one program, a code set or an instruction set is loaded and executed by the processor to implement the thruster fault identification method based on the sliding mode observer provided by the above-mentioned method embodiments.

[0117] An embodiment of the present application also provides a computer-readable storage medium, on which is stored at least one instruction, at least one program, code set or instruction set, and the at least one instruction, at least one program, code set or instruction set is loaded and executed by a processor to implement the thruster fault identification method based on a sliding mode observer provided in the above-mentioned method embodiments.

[0118] An embodiment of the present application also provides a computer program product, which includes a computer program. A processor of a computer device reads the computer program from a computer-readable storage medium, and the processor executes the computer program, so that the computer device executes the thruster fault identification method based on a sliding mode observer described in any of the above embodiments.

[0119] For the convenience of description, the above system or device is described by dividing it into various modules or units according to its functions. Of course, when implementing the present application, the functions of each unit can be implemented in the same or multiple software and / or hardware.

[0120] It can be known from the description of the above implementation methods that those skilled in the art can clearly understand that the present application can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application can be essentially or partly contributed to the prior art in the form of a software product, which can be stored in a storage medium such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in the various embodiments of the present application or certain parts of the embodiments.

[0121] Finally, it should be noted that, in this article, relational terms such as first, second, third and fourth are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0122] The above is only a preferred implementation of the present application. 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 application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A thruster fault identification method based on sliding mode observer, characterized in that: The method comprises: Based on the spacecraft dynamics model, a sliding mode observer is designed; the sliding mode observer is used to estimate the three-axis angular velocity of the spacecraft; Based on the gyro output of the spacecraft system, the real three-axis angular velocity of the spacecraft in the current control cycle is calculated; estimating the three-axis angular velocity of the spacecraft in the current control period based on the sliding mode observer; Determining a residual function of a current control cycle based on the actual three-axis angular velocity and the estimated three-axis angular velocity; Based on the relationship between the residual function and the preset threshold, it is determined whether there is a thruster fault in the current control cycle; if there is, a thruster fault matrix estimated in the current control cycle is calculated based on the residual function, and an angle between the thruster fault matrix estimated in the current control cycle and each column in a predetermined thruster fault matrix is ​​calculated, and a thruster corresponding to a column with the smallest angle is determined as a faulty thruster.

2. The method according to claim 1, characterized in that: The spacecraft dynamics model is: in, The sliding mode observer satisfies the following formula: Where I is the moment of inertia; U = diag(T1, T2, T3) is the desired output torque matrix, T1, T2 and T3 are the desired output torques of the spacecraft on the x-axis, y-axis and z-axis respectively; ω = [ω1 ω2 ω3] T is the true three-axis angular velocity of the spacecraft, ω1, ω2 and ω3 are the angular velocities of the x-axis, y-axis and z-axis respectively; is the differential of ω; ω x is the antisymmetric matrix of ω; D is the thruster fault matrix, Indicates that D is 3×N thrust The real matrix, N thrust is the number of thrusters; f t,i Indicates the failure of thruster i, i = 1, 2, ... N thrust ; d is the external interference torque, satisfying is the maximum boundary of the external disturbance torque d; ||·|| represents the norm; is the estimated thruster fault matrix; L is a positive definite matrix, L∈R 3×3 ; The estimated three-axis angular velocity of the spacecraft output by the sliding mode observer; for The differential of for The antisymmetric matrix of .

3. The method according to claim 1, characterized in that The method of calculating the true three-axis angular velocity of the spacecraft in the current control period based on the gyro output of the spacecraft system includes: Determining whether the gyroscope is a gyroscope with three axes orthogonally installed; If yes, the three-axis angular velocity output by the gyroscope is used as the three-axis angular velocity of the spacecraft; If not, determine the three-axis angular velocity of the spacecraft based on the following formula; Where ω is the true three-axis angular velocity of the spacecraft, ω1, ω2 and ω3 are the angular velocities of the x-axis, y-axis and z-axis respectively; V is the installation matrix of the gyroscope; g1, g2 to g s are the output angular velocities of the gyroscopes, and s is the number of gyroscopes.

4. The method according to claim 1, characterized in that: The calculation formula of the residual function is: Where r(t) is the residual function at time t, ω(t) is the true three-axis angular velocity of the spacecraft at time t; is the estimated three-axis angular velocity of the spacecraft output by the sliding mode observer at time t.

5. The method according to claim 1, characterized in that: The determining whether there is a thruster fault in the current control cycle based on the relationship between the residual function and a preset threshold value includes: Determining whether the residual function is less than the preset threshold; If so, it is determined that there is no thruster fault in the current control cycle; If not, it is determined that there is a thruster fault in the current control cycle.

6. The method according to claim 1, characterized in that The preset threshold is a time-varying threshold, and the preset threshold at each moment is determined using the following formula: In the formula, J th (t) is the preset threshold at time t, which is used to represent the upper bound of the residual evaluation function; t is the time; k and λ are positive numbers, and the two parameters satisfy ||e Λt ||≤ke -λt , Λ is a stable matrix; γ1 is the Lipschitz constant with respect to ω, satisfying ε is a constant, satisfying is; I is the moment of inertia; is the maximum boundary of the external interference torque d.

7. The method according to claim 6, characterized in that The thruster fault matrix estimated for each control cycle is determined using the following formula: In the formula, and are the thruster fault matrices estimated at time t and time t-1; γ and δ s is a positive real number; r(t) is the residual function at time t; U = diag(T1, T2, T3) is the expected output torque matrix, T1, T2 and T3 are the expected output torques of the spacecraft x-axis, y-axis and z-axis respectively; P is a symmetric matrix, and P satisfies the following conditions: Where, Ω1=C T P+PΓ+||I -1 || 2 c1 2 I+2PP,Γ=-I -1 L; Ω1 and Γ are both intermediate parameters; L is a positive definite matrix, L∈R 3×3 .

8. The method according to claim 1, characterized in that The faulty thruster is determined using the following formula: In the formula, i f is the thruster serial number of the failure; d i is the i-th column of the thruster fault matrix D; is the estimated thruster fault matrix; N thrust is the number of thrusters; norm(·) means modulus; dot(·) means dot multiplication operation.

9. A thruster fault identification device based on a sliding mode observer, characterized in that: The device comprises: A design unit is used to design a sliding mode observer based on a spacecraft dynamics model; the sliding mode observer is used to estimate the estimated three-axis angular velocity of the spacecraft; A calculation unit, used for calculating the true three-axis angular velocity of the spacecraft in the current control period based on the gyro output of the spacecraft system; an estimating unit, configured to estimate the estimated three-axis angular velocity of the spacecraft in the current control period based on the sliding mode observer; A first determining unit, configured to determine a residual function of a current control cycle based on the true three-axis angular velocity and the estimated three-axis angular velocity; a second determination unit, configured to determine whether there is a thruster fault in a current control cycle based on a relationship between the residual function and a preset threshold; The third determination unit is used to calculate the thruster fault matrix estimated in the current control cycle based on the residual function when there is a thruster fault, and calculate the angle between the thruster fault matrix estimated in the current control cycle and each column in the predetermined thruster fault matrix, and determine the thruster corresponding to the column with the smallest angle as the faulty thruster.

10. A computer device, characterized in that: The computer device includes a memory and a processor, the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory to implement the steps of any one of the methods described in claims 1-8.

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