Multi-information-based engine fault fusion discrimination method

Abstract

The invention discloses an engine fault fusion discrimination method based on multi-information, and the method comprises the steps: a control system obtains the centroid and centroid motion parameters of a rocket through a strapdown inertial measurement unit, and obtains the angular velocity and apparent acceleration of three axes through the collection, conversion and calculation of signals; and obtaining angular acceleration information by using the angular velocity based on an extended state observer. Meanwhile, thrust is identified on line through engine installation angle information, real-time swing angle information and quality characteristic information of the rocket, and engine faults are diagnosed in real time in combination with thrust information provided by an engine power system.

Description

Technical Field

[0001] The invention relates to the field of launch vehicle control systems, in particular to an engine fault fusion judgment method based on multi-information. Background Art

[0002] Rocket engine failure is a common system in the aerospace field. After failure, the thrust is reduced. For non-fatal engine failure, based on the degree of thrust reduction, the control system can reconstruct the control through online trajectory planning and control. Under certain circumstances, the flight mission can still be saved or the flight mission can be completed by entering the emergency orbit for degradation. Here, engine fault identification as the basis of control reconstruction has important research value and significance. Summary of the invention

[0003] The technical problem solved by the present invention is: to provide an engine fault fusion judgment method based on multi-information to solve the problem of online diagnosis of rocket engine faults outside the atmosphere.

[0004] The technical solution of the present invention is: a method for fusion identification of engine faults based on multi-information, comprising:

[0005] The control system estimates the angular acceleration information by acquiring the angular velocity information, and identifies the engine thrust by combining the acquired apparent acceleration information, the engine installation angle information, the swing angle information and the mass characteristic information, and gives the engine thrust identification result; the power system gives the engine thrust information based on its own fault diagnosis method;

[0006] The engine thrust identification result provided by the control system and the engine thrust information provided by the power system are used to verify each other and perform engine fault fusion judgment.

[0007] Furthermore, it is applied to fault diagnosis of rocket engines with N engines installed. After the rocket flies out of the atmosphere, the apparent acceleration information and angular velocity information obtained by the inertial measurement combination of the control system are used, combined with the engine installation angle information, swing angle information and mass characteristic information to perform online identification of the engine thrust, and the engine thrust identification result is given in real time; 1≤N≤6.

[0008] Furthermore, it is applied to fault diagnosis of rocket engines installed in a two-engine form, and the thrust identification results of the two engines are given in real time.

[0009] Furthermore, the real-time thrust identification results of the two engines are obtained as follows:

[0010] S1, obtain the three-axis angular velocity (ω z1 ,ω y1 ,ω x1 ), rocket three-axis apparent acceleration

[0011] S2, using the extended state observer, based on the three-axis angular velocity (ω z1 ,ω y1 ,ω x1 ), and get the three-axis angular acceleration z 2i (i=x,y,z);

[0012] S3, according to the three-axis apparent acceleration and the three-axis angular acceleration z 2i (i=x, y, z) to obtain the sensitive information matrix Y(k); obtain the coefficient matrix Φ(k) according to the installation angle information, swing angle information and quality characteristic information of the engine;

[0013] S4. Use the following formula to obtain the engine thrust identification result:

[0014]

[0015] is the thrust identification result of the first engine at time k;

[0016] is the thrust identification result of the second engine at time k;

[0017] λ is the forgetting factor and I is the identity matrix.

[0018] Furthermore, the coefficient matrix

[0019]

[0020] In the formula,

[0021]

[0022]

[0023] In the formula,

[0024]

[0025] In the formula, is the installation angle, Indicates the servo swing angle;

[0026]

[0027] Where m0 is the initial mass, is the consumption in seconds, t fly For flight time.

[0028] Furthermore, based on its own fault diagnosis method, the power system provides engine thrust information, which is divided into five levels: thrust deviation within ±5% of the preset value, thrust deviation between +5% and +10% of the preset value, thrust deviation above +10% of the preset value, thrust deviation between -5% and -10% of the preset value, and thrust deviation below -10% of the preset value.

[0029] Furthermore, when the engine thrust information provided by the power system is at the set fault diagnosis level, and at the same time the thrust identification result of the engine provided by the control system also reaches the same thrust deviation with the predetermined value in the fault diagnosis level, it is determined that the engine is faulty.

[0030] Furthermore, the fault diagnosis level is that the thrust deviation is greater than a predetermined value of +10% or the thrust deviation is less than a predetermined value of -10%.

[0031] The present invention also provides a computer program product, which implements the steps of the method when executed by a processor.

[0032] The present invention also provides an arrow computing terminal, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the steps of the method are implemented when the processor executes the computer program.

[0033] The advantages of the present invention compared with the prior art are:

[0034] (1) The present invention proposes a method for fusion identification of engine faults based on multi-information during the flight of a launch vehicle. The control system obtains the center of mass and orbital motion parameters of the rocket through the strapdown inertial unit, and obtains the angular velocity and apparent acceleration of the three axes through signal collection, conversion and calculation. Angular velocity is used to obtain angular acceleration information based on an extended state observer. At the same time, the rocket's engine installation angle information, real-time swing angle information, and mass characteristic information are used to identify thrust online, and combined with the thrust information provided by the engine power system, engine faults are diagnosed in real time.

[0035] (2) The method proposed in the present invention can effectively diagnose whether each engine in a two-engine installation configuration is faulty. The method adopted is simple and efficient, and is an innovative, practical, and effective engineering design method. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The engine installation in the embodiment of the present invention (rear view);

[0037] Figure 2 This is a block diagram of the engine fault diagnosis principle of the present invention;

[0038] Figure 3A schematic diagram of thrust information for power system fault diagnosis in an embodiment of the present invention;

[0039] Figure 4 The simulation analysis results in the embodiment of the present invention are Figure 1 ;

[0040] Figure 5 The simulation analysis results in the embodiment of the present invention are Figure 2 . DETAILED DESCRIPTION

[0041] In order to better understand the technical solution of the present invention, the specific implementation mode of the present invention is described in detail below with reference to the accompanying drawings.

[0042] In this implementation, the two engines and actuators of the launch vehicle are installed as follows: Figure 1 As shown. Four servo structures are installed on the two engines X1 and X2. During flight, the attitude control system will give real-time information on the swing angle command of each servo mechanism to drive the engine. According to the installation form, the force and torque magnitude of each engine on the three axes of the rocket body can be decomposed.

[0043] This method comprises the following steps: Figure 2 As shown:

[0044] 1) Obtain the three-axis angular velocity (ω) of the rocket body coordinate system through the strapdown inertial unit (SIMU) z1 ,ω y1 ,ω x1 )

[0045] Obtain the apparent acceleration of the rocket's three axes through the strapdown measurement device The maximum information that can be obtained is given here, a total of 6. The number of engines to be identified cannot exceed 6. In this embodiment, 2 rocket engines are taken as an example.

[0046] 2) Calculation of three-axis angular acceleration z 2i (i=x,y,z), can be calculated using the following formula

[0047] z 1i (k) = z 1i (k-1)+z 2i (k-1)·h+β 1i (ω i1 (k)-z 1i (k-1))h

[0048] z 2i (k) = z 2i (k-1)+β 2i (ω i1 (k)-z 1i (k-1))h

[0049] Among them, ω i1 is the angular velocity calculated in, h is the control period, which is selected as 0.01s here; k is the discrete cycle count, with an initial value of 0; β 2i is the coefficient of the extended state observer;

[0050] z 1i (0) = z 1i (-1) = 0, z 2i (0) = z 2i (-1)=0, i=x,y,z.

[0051] 3) The sensitive information matrix is ​​obtained from steps 1 and 2:

[0052]

[0053] 4) Construct coefficient matrix

[0054]

[0055] in, is the installation angle, the swing angle

[0056] Indicates the servo swing angle;

[0057] m represents mass, and the calculation formula is as follows:

[0058]

[0059] Where m0 is the initial mass, is the consumption in seconds, t fly For flight time.

[0060] 5) Use the following formula to obtain the engine thrust identification result:

[0061]

[0062] is the thrust identification result of the first engine X1 at time k;

[0063] is the thrust identification result of the second engine X2 at time k;

[0064] λ is the forgetting factor and I is the identity matrix.

[0065] K(k) is a 2×3 gain matrix, and P(k) is a 2×2 information matrix;

[0066] The initial values ​​of each parameter are as follows:

[0067] λ is taken as 0.96.

[0068] 6) Engine diagnostic information

[0069] The power system provides engine thrust information based on its own fault diagnosis method; refer to Figure 3 Based on its own fault diagnosis method, the power system provides engine thrust information, which is divided into five levels: thrust deviation within ±5% of the preset value, thrust deviation between +5% and +10% of the preset value, thrust deviation above +10% of the preset value, thrust deviation between -5% and -10% of the preset value, and thrust deviation below -10% of the preset value.

[0070] The engine thrust identification result given by the control system and the engine thrust information given by the power system are used to verify each other, and the engine fault fusion judgment is performed to improve the reliability of fault diagnosis.

[0071] 7) Engine diagnostic strategy

[0072] Based on the engine information in 6), when the thrust deviation given by the thrust information is more than 10% of the preset value, it is diagnosed as an engine failure, and the flag word 02 is given according to the level; if at the same time, the thrust information of a certain engine given in 5) drops by more than 10%, it is determined to be an engine failure.

[0073] Engine thrust identification simulation analysis:

[0074] For the thrust reduction failure of a single engine, thrust failures were added at 495s (before entering the second stage of flight), 520s, and 1600s, and preliminary simulation research was carried out; the main results Figure 4 and Figure 5 As shown. The ordinate in the figure is the ratio of the identified thrust to the theoretical thrust. From the simulation results of thrust identification, it can be seen that the estimation of the thrust reduction degree of the two engines has an identification accuracy of more than 91%, which has a good identification effect. The engine thrust reduction identification estimation curve converges to the true value within about 3s, and the identification speed is fast. Combined with the engine information, the fault can be diagnosed quickly.

[0075] It is to be understood that the present invention is described by way of embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and embodiments that can fall within the scope of the claims of this application all fall within the scope protected by the present invention.

[0076] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A method for fusion identification of engine faults based on multi-information, characterized in that: include: The control system estimates the angular acceleration information by acquiring the angular velocity information, and identifies the engine thrust by combining the acquired apparent acceleration information, the engine installation angle information, the swing angle information and the mass characteristic information, and gives the engine thrust identification result; the power system gives the engine thrust information based on its own fault diagnosis method; The engine thrust identification result provided by the control system and the engine thrust information provided by the power system are used to verify each other and perform engine fault fusion judgment.

2. The engine fault fusion judgment method based on multi-information according to claim 1 is characterized in that: It is used to identify faults of rocket engines with N engines installed. After the rocket flies out of the atmosphere, the apparent acceleration information and angular velocity information obtained by the inertial measurement combination of the control system are used to identify the engine thrust online in combination with the engine installation angle information, swing angle information and mass characteristic information, and the engine thrust identification result is given in real time; 1≤N≤6.

3. The engine fault fusion judgment method based on multi-information according to claim 2 is characterized in that: It is used to identify faults of rocket engines installed in a two-engine form and provide thrust identification results of the two engines in real time.

4. The engine fault fusion judgment method based on multi-information according to claim 3 is characterized in that: The real-time thrust identification results of the two engines are obtained as follows: S1, obtain the three-axis angular velocity (ω z1 ,ω y1 ,ω x1 ), rocket three-axis apparent acceleration S2, using the extended state observer, based on the three-axis angular velocity (ω z1 ,ω y1 ,ω x1 ), and get the three-axis angular acceleration z 2i (i=x,y,z); S3, according to the three-axis apparent acceleration and the three-axis angular acceleration z 2i (i=x, y, z) to obtain the sensitive information matrix Y(k); construct the coefficient matrix Φ(k) according to the engine installation angle information, swing angle information and quality characteristic information; S4. Use the following formula to obtain the engine thrust identification result: is the thrust identification result of the first engine at time k; is the thrust identification result of the second engine at time k; λ is the forgetting factor and I is the identity matrix.

5. The engine fault fusion identification method based on multi-information according to claim 4 is characterized in that: Coefficient Matrix In the formula, In the formula, In the formula, is the installation angle, Indicates the servo swing angle; Where m0 is the initial mass, is the consumption in seconds, t fly For flight time.

6. The engine fault fusion judgment method based on multi-information according to claim 1 is characterized by: Based on its own fault diagnosis method, the power system provides engine thrust information, which is divided into five levels: thrust deviation within ±5% of the preset value, thrust deviation between +5% and +10% of the preset value, thrust deviation above +10% of the preset value, thrust deviation between -5% and -10% of the preset value, and thrust deviation below -10% of the preset value.

7. The engine fault fusion identification method based on multi-information according to claim 6 is characterized in that: When the engine thrust information provided by the power system is at the set fault diagnosis level, and at the same time the thrust identification result of the engine provided by the control system also reaches the same thrust deviation with the predetermined value in the fault diagnosis level, the engine fault is determined.

8. The engine fault fusion identification method based on multi-information according to claim 7 is characterized in that: The fault diagnosis level is that the thrust deviation is greater than a predetermined value of +10% or the thrust deviation is less than a predetermined value of -10%.

9. A computer program product, characterized in that: When the computer program product is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

10. An arrow computing terminal, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method as claimed in any one of claims 1 to 8 when executing the computer program.

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