A vector engine deflection angle correction control method based on aerodynamic force prediction

Abstract

The application belongs to the field of aerodynamic force prediction, and relates to a vector engine deflection angle correction control method based on aerodynamic force prediction. Through bench test and high-altitude test, bench test and high-altitude test data are obtained, aerodynamic mechanism analysis is performed, and main factors influencing deformation are determined. Then, corresponding deviation prediction models are established according to the main factors influencing deformation. Finally, the real nozzle throat position and up-down adjusting piece position are calculated according to the deviation prediction models, and the nozzle throat actuating position and up-down adjusting piece actuating position that need to be adjusted are calculated through geometric forward and reverse solution formulas. The problem of vector angle deviation caused by elastic deformation of the nozzle mechanism can be effectively solved, and the elastic deformation amount can be estimated and predicted according to aerodynamic parameters in a specific flight area.

Description

Technical Field

[0001] This application belongs to the field of aerodynamic prediction, and specifically relates to a vector engine deflection angle correction control method based on aerodynamic prediction. Background Technology

[0002] Fighter jets equipped with two-dimensional thrust vectoring engines possess control torques in two directions, enabling them to perform high angle-of-attack post-stall maneuvers that conventional aircraft cannot, thus demonstrating significant application potential. However, in actual use, due to the structural characteristics of the two-dimensional vectoring nozzle, structural deformation can easily occur in specific areas. Especially under harsh conditions such as high Mach number flight, the nozzle's convergent and divergent flaps bear strong aerodynamic loads, resulting in elastic deformation. This causes deviations in the vector angle controlled according to preset geometric relationships, leading to deviations in the required lateral force. This is detrimental to the aircraft's maneuverability and attitude maintenance under specific conditions, requiring solutions. Since the structural characteristics are not easily altered, it is necessary to assess the vector angle of the two-dimensional vectoring nozzle to eliminate the influence of elastic deformation and achieve precise angle control.

[0003] Currently, existing technologies mostly check the accuracy of vector angle control by pre-setting geometric relationships to check whether the motion actuator is in place. Specifically, the motion actuator is controlled according to mathematical and geometric relationships based on geometric forward and inverse formulas. Only the displacement of the motion actuator is monitored. The elastic deformation of the vector nozzle adjustment plate and the actual aerodynamic position changes are not considered. Therefore, there are no corresponding identification and correction control methods for deformation, which leads to deviations in vector angle and lateral thrust in specific areas.

[0004] Therefore, how to more accurately control the vector angle of a two-dimensional vector nozzle is a problem that needs to be solved. Summary of the Invention

[0005] The purpose of this application is to provide a vector engine deflection angle correction control method based on aerodynamic prediction, so as to solve the problem that the prediction of vector angle in the prior art does not take into account the elastic deformation of the vector nozzle adjustment plate and the actual aerodynamic position changes, resulting in insufficient prediction accuracy.

[0006] The technical solution of this application is: a vector engine deflection angle correction control method based on aerodynamic prediction, comprising:

[0007] Based on the basic principle of vector angle control, the factors affecting the vector angle are determined to be the position of the throat A8 and the upper and lower adjusting plates A9.

[0008] Conduct bench tests and high-altitude test tests to obtain test data. Based on the test data, establish A8 deviation prediction model and A9 deviation prediction model respectively.

[0009] Based on the A8 deviation prediction model and the A9 deviation prediction model, and with all corrected input parameters, the deviation values ​​deltaA8 and deltaA9 of A8 and A9 are calculated to obtain the actual actuation positions of A8 and A9. These values ​​are then substituted into the geometric forward and inverse solution formulas to calculate the required adjustment positions of A8 (La8) and A9, thus deriving the throat adjustment coefficient X_. La8修 , Adjustment coefficient X_ of the upper adjustment plate La9S修 Adjustment coefficient X_ of the lower adjustment plate La9X修 Ultimately, the required control target angle is obtained.

[0010] Preferably, the A8 deviation calculation model is as follows:

[0011] deltaA8=[a*(p6-p h ) 2 +b*(p6-p h )+c]*X n *X P *X pla

[0012] In the formula, P6 is the tank pressure, P h X represents the exhaust pressure after the turbocharger, a, b, and c are coefficients of the fitting formula, and X... n For speed correction, X p To account for corrections made to pressure deviations, X pla The correction was made to account for the increase in aerodynamic forces during engine afterburner.

[0013] Preferably, the A9 deviation prediction model is as follows:

[0014] deltaA9S=deltaA8*X 几何折算S *X δ

[0015] deltaA9X=deltaA8*X 几何折算X *X δ

[0016] In the formula, S represents the upper adjustment piece, and X represents the lower adjustment piece; X 几何折算 Based on the magnification factor between A8 and A9, X δ This is the deflection correction factor.

[0017] Preferably, the magnification factor is determined by the geometric relationship between A8 and A9.

[0018] Preferably, the target angle is:

[0019] δ 目标 =f(A8, vector angle, area ratio, X_) La9S修 ,X_ La9X修 ).

[0020] Preferably, when performing aerodynamic mechanism analysis, multiple nodes are set at intervals along the axial direction of the engine nozzle, and the internal pressure, external pressure, temperature, and structural parameters of each node are obtained. The structural deformation is calculated by using the structural parameters of adjacent nodes, and the structural deformation is compared and analyzed with the internal pressure, external pressure, temperature, and other parameters to determine the influencing factors of the structural deformation.

[0021] This application presents a vector engine deflection angle correction control method based on aerodynamic prediction. First, bench tests and high-altitude tests are conducted to obtain test data. Aerodynamic mechanism analysis is then performed to determine the main factors affecting deformation. Next, corresponding deviation prediction models are established based on these main factors. Finally, the actual nozzle throat position and upper / lower adjuster positions are calculated using these prediction models. Then, the required adjustment positions of the nozzle throat and upper / lower adjusters are calculated using geometric forward and inverse kinematics formulas. This method effectively solves the problem of vector angle deviation caused by elastic deformation of the nozzle mechanism. It achieves two main functions: elastic deformation prediction and vector angle correction control, enabling the estimation and prediction of elastic deformation based on aerodynamic parameters within a specific flight area. Attached Figure Description

[0022] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application.

[0023] Figure 1 This is a schematic diagram of the overall process of this application. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] A vector engine deflection angle correction control method based on aerodynamic prediction is proposed. First, bench tests and high-altitude tests are conducted. Using the test data and theoretical calculations, a deformation prediction model of the engine vector nozzle mechanism based on flight conditions and aerodynamic parameters is formed. After completing the theoretical model, a real-time deformation prediction algorithm based on the installed parameters is designed. Finally, a vector angle correction control method is designed based on the predicted deformation. After correction, vector angle correction control can be achieved.

[0026] like Figure 1 As shown, it includes the following steps:

[0027] Step S100: Determine the object to be corrected for the vector angle.

[0028] According to the basic principle of vector angle control, there are two main factors affecting the vector angle. Factor 1 is the accurate position of the throat A8, which determines whether the reference for calculating the vector angle is accurate. Factor 2 is the accuracy of the position of the upper and lower adjustment plates A9, which directly affects the accuracy of the angle. Therefore, two corrections are required for these two factors: A8 reference correction and vector deviation A9 correction.

[0029] Step S200: Determine the aerodynamic prediction model

[0030] Based on existing conditions, an aerodynamic deformation prediction model is established, specifically by conducting bench tests and high-altitude tests, acquiring test data, performing aerodynamic mechanism analysis, and determining the main factors affecting deformation.

[0031] When performing aerodynamic mechanism analysis, multiple nodes are set at intervals along the axial direction of the engine nozzle. The internal pressure, external pressure, temperature, and structural parameters of each node are obtained. The structural deformation is calculated by using the structural parameters of adjacent nodes. The structural deformation is compared and analyzed with parameters such as internal pressure, external pressure, and temperature to determine the influencing factors of the structural deformation.

[0032] The final determined influencing factor was the internal and external pressure difference distributed along the engine nozzle.

[0033] 1) Establish an A8 deviation prediction model

[0034] Since detailed parameters cannot be accurately obtained, simplified substitutions can be made using characterization parameters for easier prediction.

[0035] The method for simplifying and replacing the characterization parameters in this application is as follows: After conducting bench tests and high-altitude tests to obtain test data, the deformation is simplified and fitted to the mathematical relationship between the external pressure (replaced by chamber pressure) and the internal pressure (replaced by turbine exhaust pressure), forming an aerodynamic deformation prediction model. The A8 deviation calculation model is then as follows:

[0036] deltaA8=[a*(p6-p h ) 2 +b*(p6-p h )+c]*X n *X P *X pla

[0037] Where P6 is the cabin pressure, P h The exhaust pressure after the turbine; the coefficients a, b, and c of the fitting formula can be determined based on strength calculations or by substituting experimental data into the calculations. Other correction coefficients are: X n For speed correction, X p To account for corrections made to pressure deviations, X pla The corrections made to account for the increase in aerodynamic forces under engine afterburner conditions can all be given based on theoretical or experimental results.

[0038] 2) Establish an A9 deviation prediction model

[0039] The deviation of the upper and lower regulating vanes is mainly related to the A8 deviation calculation model deltaA8, the area ratio, and the vector deflection angle δ. Since the vector deflection of the regulating vanes is affected not only by the A8 position but also by aerodynamic forces, the regulating vanes closer to the core flow are blown away and deformed. Considering that the aerodynamic forces on the upper and lower regulating vanes are different, and that the deviation of the throat position affects the actuation positions of the upper and lower regulating vanes (specifically, through a certain amplification), the A9 deviation prediction model is as follows:

[0040] deltaA9S=deltaA8*X 几何折算S *X δ

[0041] deltaA9X=deltaA8*X 几何折算X *X δ

[0042] In the formula: S represents the upper adjustment piece, and X represents the lower adjustment piece; X 几何折算 The magnification factor, determined based on the geometric relationship between A8 and A9, primarily depends on the geometric relationship between the motion models. Depending on the type of vector nozzle, a larger magnification factor results in a larger difference between the throat size and the axial dimension of the adjusting vane, and a smaller magnification factor results in a smaller difference between the throat size and the axial dimension of the adjusting vane. δThe deflection correction factor primarily considers the deviation correction caused by the re-deformation of the airflow near the core due to vector deflection. It is a function of the vector deflection angle δ. The deflection correction factor is positively correlated with the vector deflection angle; the larger the vector deflection angle, the larger the deflection correction factor; and the smaller the vector deflection angle, the smaller the deflection correction factor.

[0043] Step S300: Perform vector angle correction control based on the aerodynamic prediction model.

[0044] Based on the A8 and A9 deviation prediction models, given all corrected input parameters, including [H,M,P6,P...], h [,n2,pla,δ], where H is the height, M is the mass, n2 is the engine speed, and pla is the aerodynamic force of the engine in afterburner mode.

[0045] Based on the two prediction models, the deviations deltaA8 and deltaA9 of A8 and A9 are calculated, thus obtaining the actual A8 and A9 at this point. These values ​​are then substituted into the geometric forward and inverse solution formulas for control to calculate the required adjustment positions of A8 (La8) and A9 (La9S and La9X, distinguishing between upper and lower sides), thus deriving the throat adjustment coefficient X_. La8修 , Adjustment coefficient X_ of the upper adjustment plate La9S修 Adjustment coefficient X_ of the lower adjustment plate La9X修 This is used to adjust the actuation position, thus obtaining the actual required control target angle, making the actual angle consistent with the commanded angle. The control target angle is as follows:

[0046] δ 目标 =f(A8, vector angle, area ratio, X_) La9S修 ,X_ La9X修 ).

[0047] This application first conducts bench tests and high-altitude tests to obtain test data, and then performs aerodynamic mechanism analysis to determine the main factors affecting deformation. Next, corresponding deviation prediction models are established based on these main factors. Finally, based on the deviation prediction models, the actual nozzle throat position and the positions of the upper and lower adjusting vanes are calculated. Then, the required adjustment positions of the nozzle throat and the upper and lower adjusting vanes are calculated using geometric forward and inverse kinematics formulas. This effectively solves the problem of vector angle deviation caused by elastic deformation of the nozzle mechanism, achieving two main functions: elastic deformation prediction and vector angle correction control. It enables the estimation and prediction of elastic deformation based on aerodynamic parameters within a specific flight area, and the correction control of the vector angle based on the deformation prediction results. This achieves the initial goal of "overcoming" elastic deformation interference, effectively improving the accuracy and precision of vector angle control, enhancing the functional performance characteristics of the vector engine, and further meeting the engine's requirements for vector flight.

[0048] Finally, it should be noted that the accompanying drawings of the embodiments disclosed in this invention only involve the structures involved in the embodiments disclosed in this invention. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other.

[0049] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A vector engine deflection angle correction control method based on aerodynamic force prediction, characterized by, Comprise: According to the basic principle of vector angle control, determine the elements affecting the vector angle as the throat A8 and the position of the upper and lower two sides of the adjusting piece A9; Carry out bench test and high altitude test, obtain bench test and high altitude test data, and respectively establish A8 deviation amount prediction model and A9 deviation amount prediction model according to the bench test and high altitude test data; According to the A8 deviation amount prediction model and the A9 deviation amount prediction model and all the modified input parameters, the A8 deviation amount deltaA8 and the A9 deviation amount deltaA9 are calculated, the real A8 and A9 actuating positions are obtained, and then are brought into the geometric positive and negative solution calculation formula to calculate the A8 actuating position La8 and the A9 actuating position that need to be adjusted, and the throat adjusting coefficient X La8修 , the upper adjusting piece adjusting coefficient X La9S修 , the lower adjusting piece adjusting coefficient X La9X修 , and finally the actual required control target angle amount is obtained.

2. The vector engine deflection angle correction control method based on aerodynamic force prediction according to claim 1, characterized by, The A8 deviation amount calculation model is: deltaA8 = [a*(p6-p h ) 2 +b*(p6-p h )+c]*X n *X P *X pla where P6 is cabin pressure, P h is turbine discharge pressure, a, b, c are coefficients of the fitting formula, X n is speed correction, X p is correction considering pressure deviation, X pla is correction considering increase of aerodynamic force in engine afterburner state.

3. The method of claim 1, wherein the method further comprises: determining a deflection angle of the vector engine; and determining a deflection angle correction value based on the deflection angle and the predicted aerodynamic force. The A9 deviation amount prediction model is: deltaA9S = deltaA8 * X 几何折算S *X δ deltaA9X = deltaA8 * X 几何折算X *X δ In the formula, S represents the upper adjusting piece, and X represents the lower adjusting piece; X 几何折算 is the amplification conversion coefficient between A8 and A9, X δ is the deflection correction coefficient.

4. The method of claim 3, wherein: The amplification conversion coefficient is determined by the geometric relationship between A8 and A9.

5. The method of claim 1, wherein the method further comprises: determining a deflection angle of the vector engine; and determining a deflection angle correction value based on the deflection angle and the predicted aerodynamic force. The control target angle quantity is: delta 目标 = f(A8, vector angle, area ratio, X La9S修 , X La9X修 ).

6. The method of claim 1, wherein: When performing aerodynamic mechanism analysis, multiple nodes are arranged along the axial direction of the engine nozzle, the internal pressure, external pressure, temperature and structural parameters at each node are obtained, the structural deformation amount is calculated through the structural parameters of adjacent nodes, and the structural deformation amount is compared and analyzed with the internal pressure, external pressure and temperature to determine the influencing factors of the structural deformation amount.

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