Unsteady Aerodynamic Force Calculation Accuracy Evaluation and Correction Method

Abstract

The present invention provides a method for evaluating and correcting the calculation accuracy of unsteady aerodynamic forces, including: establishing a full-aircraft dynamics model and a full-aircraft aerodynamic force grid model; constructing the rigid-body modal vibration modes of the aircraft rotation and the rigid-body modal vibration modes of the control surface deflection; interpolating the modal vibration modes into the full-aircraft aerodynamic force grid model; calculating and obtaining the unsteady aerodynamic moments of each channel; calculating and obtaining the control moments of each channel based on the control surface force measurement wind tunnel test data; calculating and obtaining the unsteady aerodynamic force accuracy evaluation values of each channel according to the unsteady aerodynamic moments and control moments of each channel; comparing the unsteady aerodynamic force accuracy evaluation values of each channel with the set aerodynamic force accuracy evaluation threshold ranges of the corresponding channels respectively, and realizing accuracy correction according to the accuracy evaluation values. By applying the technical solution of the present invention, the technical problem in the prior art that it is difficult to evaluate the accuracy of unsteady aerodynamic forces because they cannot be verified by experimental measurement data is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of aerodynamic analysis, and particularly to a method for evaluating and correcting the calculation accuracy of unsteady aerodynamic forces. Background Art

[0002] Unsteady aerodynamic forces are an important part of the calculation and analysis of aircraft aeroelastic dynamics, and are one of the basic original data for the analysis of flutter, aeroservoelasticity, aeroelastic dynamic response, etc. At present, there are mainly two types of approximate solution methods for unsteady aerodynamic forces: one is the approximate method of unsteady aerodynamic forces based on the frequency domain, which obtains the aerodynamic coefficient matrix (complex number) of discrete reduced frequencies; the other is the solution method of unsteady aerodynamic forces based on the time domain, which is based on the coupled solution of the N-S equation and the Euler equation by CFD / CSD to obtain the time-domain aerodynamic coefficients. Among them, the approximate method of unsteady aerodynamic forces based on the frequency domain is also called the engineering method, which has the characteristics of high calculation efficiency, meets the needs of weak nonlinear engineering analysis at small angles of attack, and has been widely used in the development of various engineering models.

[0003] The unsteady aerodynamic force data directly affects the accuracy of the aeroelastic dynamics analysis results. In engineering analysis, it is affected by factors such as the deviation of the aerodynamic force grid model and the approximate solution method, resulting in errors in the calculated values of unsteady aerodynamic forces, and it is difficult to obtain accurate values through ground test techniques. Summary of the Invention

[0004] The present invention provides a method for evaluating and correcting the calculation accuracy of unsteady aerodynamic forces to solve the technical problem in the prior art that it is difficult to evaluate the accuracy of unsteady aerodynamic forces because they cannot be verified by experimental measurement data.

[0005] The present invention provides a method for evaluating and correcting the calculation accuracy of unsteady aerodynamic forces. The method for evaluating and correcting the calculation accuracy of unsteady aerodynamic forces includes: establishing a full-aircraft dynamics model and a full-aircraft aerodynamic grid model; based on the full-aircraft dynamics model, constructing the rigid-body mode shapes of the aircraft's rotation in the pitch, yaw, and roll channels and the rigid-body mode shapes of the control surface deflection; interpolating the rigid-body mode shapes of the aircraft's rotation in the three channels and the rigid-body mode shapes of the control surface deflection into the full-aircraft aerodynamic grid model; based on the interpolated full-aircraft aerodynamic grid model, using the frequency-domain unsteady aerodynamic force solution method to calculate and obtain the unsteady aerodynamic forces of each channel of the aircraft; calculating and obtaining the unsteady aerodynamic moments of each channel according to the unsteady aerodynamic forces of each channel; based on the control surface force measurement wind tunnel test data, calculating and obtaining the control forces provided to the aircraft by the unit angle deflection of the control surface in each channel, and calculating and obtaining the control moments of each channel according to the control forces provided to the aircraft by the unit angle deflection of the control surface in each channel; calculating and obtaining the evaluation values of the calculation accuracy of the unsteady aerodynamic forces of each channel according to the unsteady aerodynamic moments of each channel and the control moments of each channel; comparing the evaluation values of the calculation accuracy of the unsteady aerodynamic forces of each channel with the set aerodynamic force accuracy evaluation threshold ranges of the corresponding channels respectively. When the evaluation value of the calculation accuracy of the unsteady aerodynamic force of any channel exceeds the set aerodynamic force accuracy evaluation threshold range of the corresponding channel, adjust the full-aircraft aerodynamic grid model, and repeat the above process until the evaluation values of the calculation accuracy of the unsteady aerodynamic forces of all channels are within the set aerodynamic force accuracy evaluation threshold ranges of the corresponding channels, thus completing the evaluation and correction of the calculation accuracy of the unsteady aerodynamic forces.

[0006] Further, after interpolating the rigid-body mode shapes of the aircraft's rotation in the three channels and the rigid-body mode shapes of the control surface deflection into the full-aircraft aerodynamic grid model, the method for evaluating and correcting the calculation accuracy of unsteady aerodynamic forces further includes: comparing the mode shapes of the interpolated full-aircraft aerodynamic grid model with the mode shapes before interpolation. When the difference between the mode shapes before and after interpolation is less than the preset difference, adjust the interpolation nodes, and repeat the above process until the difference between the mode shapes before and after interpolation is less than the preset difference.

[0007] Further, specifically constructing the rigid-body mode shapes of the control surface deflection of the aircraft in the pitch, yaw, and roll channels includes: constructing the rigid-body mode shapes of the control surface deflection of the aircraft in the pitch, yaw, and roll channels according to the control surface control definitions of the pitch, yaw, and roll channels.

[0008] Further, when the flight trajectory is that of a subsonic aircraft, the dipole grid method is selected as the frequency-domain unsteady aerodynamic force solution method; when the flight trajectory is that of a low-supersonic aircraft, the harmonic gradient method or the local flow piston theory is selected as the frequency-domain unsteady aerodynamic force solution method; when the flight trajectory is that of a high-speed aircraft, the unified lifting surface theory, the Van Dyke second-order piston theory, or the Newton impact theory is selected as the frequency-domain unsteady aerodynamic force solution method.

[0009] Further, the unsteady aerodynamic moment M' of each channel can be obtained according to M' = q D Q qδ δ, where q D is the dynamic pressure based on the typical state point of the flight trajectory, Q qδ is the cross term of the rigid body mode shape of the entire aircraft and the aerodynamic force of the control surface deflection rigid body mode in any channel, and δ is the deflection angle of any channel.

[0010] Further, the cross term Q qδ of the rigid body mode shape of the entire aircraft and the aerodynamic force of the control surface deflection rigid body mode in any channel can be obtained according to , where Q is the unsteady aerodynamic force influence coefficient matrix at the reduced frequency k = 0, Q qq is the self-cross term of the rigid body mode shape of the entire aircraft and the aerodynamic force in any channel, Q δδ is the self-cross term of the rigid body mode shape of the control surface deflection and the aerodynamic force in any channel, and Q δq is the cross term of the rigid body mode shape of the control surface deflection and the aerodynamic force of the entire aircraft rigid body mode in any channel.

[0011] Further, the control force R of the aircraft can be obtained according to R = q D S ref c, where q D is the dynamic pressure based on the typical state point of the flight trajectory, S ref is the reference area of the control surface, and c is the control effectiveness.

[0012] Further, the control moment M of each channel can be obtained according to M = RLθ, where L is the mapping of the centroid distance of the control moment in the direction of any channel, and θ is the deflection angle of any channel.

[0013] Further, the accuracy evaluation value E i of the unsteady aerodynamic force of each channel can be obtained according to , where Ux is the roll channel, Uy is the yaw channel, and Uz is the pitch channel.

[0014] Applying the technical solution of the present invention, a method for evaluating and correcting the calculation accuracy of unsteady aerodynamic forces is provided. This method respectively constructs the rigid body modal vibration modes of the aircraft's rotation and the rigid body modal vibration modes of the control surface deflection, and interpolates the constructed modal vibration modes into the aerodynamic grid. Based on the interpolated aerodynamic grid, the unsteady aerodynamic moments of each channel are calculated; based on the rudder effectiveness data (steady aerodynamic data) obtained from the wind tunnel force measurement test of the scaled model of the aircraft's control surface, the control moments of each channel are calculated; according to the unsteady aerodynamic moments of each channel and the control moments of each channel, the evaluation values of the calculation accuracy of the unsteady aerodynamic forces of each channel are calculated, and the calculation accuracy of each channel is corrected according to the evaluation values of the unsteady aerodynamic force calculation accuracy. The method for evaluating and correcting the calculation accuracy of unsteady aerodynamic forces provided by the present invention solves the problem that it is difficult to evaluate the accuracy of unsteady aerodynamic forces because they cannot be verified by experimental measurement data. Based on the force measurement test data of the control surface routinely carried out for the model, it has high calculation accuracy and efficiency, and can be widely applied to the evaluation of the calculation accuracy of unsteady aerodynamic forces and the correction of aerodynamic grid models for various aircraft, providing important support for the dynamic aerodynamic elasticity analysis (flutter, aerodynamic servo elasticity, etc.) of aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings included are used to provide a further understanding of the embodiments of the present invention, which form a part of the specification, are used to illustrate the embodiments of the present invention, and together with the written description are used to explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0016] Figure 1 The flowchart of the method for evaluating and correcting the calculation accuracy of unsteady aerodynamic forces provided according to the specific embodiments of the present invention is shown. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way limits the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0018] It should be noted that the terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly dictates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprises" and / or "comprising" are used in this specification, they specify the presence of the stated features, steps, operations, devices, components, and / or combinations thereof.

[0019] Unless otherwise specifically stated, the relative arrangements of the components and steps, numerical expressions and values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for the sake of convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationship. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the authorized specification. In all the examples shown and discussed herein, any specific values should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof in subsequent figures is not required.

[0020] As Figure 1As shown in the figure, according to the present invention, a method for evaluating and correcting the calculation accuracy of unsteady aerodynamic forces is provided. The method for evaluating and correcting the calculation accuracy of unsteady aerodynamic forces includes: establishing a full-aircraft dynamic model and a full-aircraft aerodynamic grid model; based on the full-aircraft dynamic model, constructing the rigid-body mode shapes of the aircraft's rotation in the pitch, yaw, and roll channels and the rigid-body mode shapes of the control surface deflection; interpolating the rigid-body mode shapes of the aircraft's rotation in the three channels and the rigid-body mode shapes of the control surface deflection into the full-aircraft aerodynamic grid model; based on the interpolated full-aircraft aerodynamic grid model, using the frequency-domain unsteady aerodynamic force solution method to calculate and obtain the unsteady aerodynamic forces of each channel of the aircraft; calculating and obtaining the unsteady aerodynamic moments of each channel according to the unsteady aerodynamic forces of each channel; based on the control surface force measurement wind tunnel test data, calculating and obtaining the control forces provided to the aircraft by the unit angle deflection of the control surface in each channel, and calculating and obtaining the control moments of each channel according to the control forces provided to the aircraft by the unit angle deflection of the control surface in each channel; calculating and obtaining the evaluation values of the unsteady aerodynamic force accuracy of each channel according to the unsteady aerodynamic moments of each channel and the control moments of each channel; comparing the evaluation values of the unsteady aerodynamic force accuracy of each channel with the set aerodynamic force accuracy evaluation threshold ranges of the corresponding channels respectively. When the evaluation value of the unsteady aerodynamic force accuracy of any channel exceeds the set aerodynamic force accuracy evaluation threshold range of the corresponding channel, adjust the full-aircraft aerodynamic grid model, and repeat the above process until the evaluation values of the unsteady aerodynamic force accuracy of any channel are all within the set aerodynamic force accuracy evaluation threshold ranges of the corresponding channels, thus completing the evaluation and correction of the calculation accuracy of unsteady aerodynamic forces.

[0021] By applying this configuration method, a method for evaluating and correcting the calculation accuracy of unsteady aerodynamic forces is provided. The method respectively constructs the rigid-body mode shapes of the aircraft's rotation and the rigid-body mode shapes of the control surface deflection, interpolates the constructed mode shapes into the aerodynamic grid, and calculates and obtains the unsteady aerodynamic moments of each channel based on the interpolated aerodynamic grid; based on the rudder effectiveness data (steady aerodynamic force data) obtained from the scaled model wind tunnel force measurement test of the aircraft's control surface, calculates and obtains the control moments of each channel; calculates and obtains the evaluation values of the unsteady aerodynamic force accuracy of each channel according to the unsteady aerodynamic moments of each channel and the control moments of each channel, and corrects the calculation accuracy of each channel according to the evaluation values of the unsteady aerodynamic force accuracy. The method for evaluating and correcting the calculation accuracy of unsteady aerodynamic forces provided by the present invention solves the problem that it is difficult to evaluate the accuracy of unsteady aerodynamic forces because they cannot be verified by experimental measurement data. Based on the control surface force measurement test data routinely carried out for the model, it has high calculation accuracy and efficiency, and can be widely applied to the evaluation of the calculation accuracy of unsteady aerodynamic forces and the correction of aerodynamic grid models for various aircraft, providing important support for the dynamic aeroelastic analysis (flutter, aeroservoelasticity, etc.) of aircraft.

[0022] In the present invention, in order to evaluate and correct the accuracy of unsteady aerodynamic force calculation, it is first necessary to establish a full-aircraft dynamics model and a full-aircraft aerodynamic force grid model. In the present invention, the full-aircraft dynamics finite model can be established by finite element software such as Hypermesh, MSC.patran, ANSYS, etc., and the full-aircraft aerodynamic force grid model can be established by aerodynamic force solution software such as ZAERO, MSC.flightloads, etc.

[0023] After the full-aircraft dynamics model and the full-aircraft aerodynamic force grid model are constructed, based on the full-aircraft dynamics model, the rigid body modal vibration modes of the aircraft in the three channels of pitch, yaw, and roll and the rigid body modal vibration modes of the control surface deflection are constructed. Specifically, in the present invention, constructing the rigid body modal vibration modes of the control surface deflection of the aircraft in the three channels of pitch, yaw, and roll specifically includes: constructing the rigid body modal vibration modes of the control surface deflection of the aircraft in the three channels of pitch, yaw, and roll according to the control surface control definitions of the three channels of pitch, yaw, and roll. Among them, the control surface control definition is to define the rudder deflection of each physical rudder surface in order to achieve flight control in each channel, and the rudder deflection should specify positive and negative (for example: the vector direction from the root chord to the tip chord along the rudder axis is positive). A modal vibration mode file of 3 + 3 order is formed according to the rigid body modal vibration modes of the aircraft rotation and the rigid body modal vibration modes of the control surface deflection.

[0024] Furthermore, after the modal vibration mode file of 3 + 3 order is formed, the rigid body modal vibration modes of the aircraft rotation and the rigid body modal vibration modes of the control surface deflection in the three channels are interpolated into the full-aircraft aerodynamic force grid model. In the present invention, in order to further improve the accuracy of unsteady aerodynamic force calculation, after the rigid body modal vibration modes of the aircraft rotation and the rigid body modal vibration modes of the control surface deflection in the three channels are interpolated into the full-aircraft aerodynamic force grid model, the method for evaluating and correcting the accuracy of unsteady aerodynamic force calculation further includes: comparing the modal vibration mode of the interpolated full-aircraft aerodynamic force grid model with the modal vibration mode before interpolation. When the difference between the modal vibration modes before and after interpolation is less than a preset difference, the interpolation nodes are adjusted, and the above process is repeated until the difference between the modal vibration modes before and after interpolation is less than the preset difference. This method can effectively improve the interpolation quality.

[0025] Next, after the interpolation of the modal vibration modes is completed, the unsteady aerodynamic forces of each channel of the aircraft can be calculated and obtained based on the interpolated full-aircraft aerodynamic grid model by using the frequency-domain unsteady aerodynamic force solution method. In the present invention, an applicable frequency-domain unsteady aerodynamic force solution method is selected according to the typical state points of the flight trajectory. The typical state points mentioned here include subsonic state, low supersonic state, and high supersonic state. Among them, when the flight trajectory is that of a subsonic aircraft, the dipole grid method is selected as the frequency-domain unsteady aerodynamic force solution method; when the flight trajectory is that of a low supersonic aircraft, the harmonic gradient method or the local flow piston theory is selected as the frequency-domain unsteady aerodynamic force solution method; when the flight trajectory is that of a high supersonic aircraft, the unified lifting surface theory, the Van Dyke second-order piston theory, or the Newton impact theory is selected as the frequency-domain unsteady aerodynamic force solution method. Using the frequency-domain unsteady aerodynamic force solution method, the unsteady aerodynamic force influence coefficient matrix (a 6×6 square matrix) at the reduced frequency k = 0 can be obtained. where Q is the unsteady aerodynamic force influence coefficient matrix at the reduced frequency k = 0, Q qq is the self-cross term of the rigid body mode shape of the full aircraft and the aerodynamic force of any channel, Q δδ is the self-cross term of the rigid body mode shape of the control surface deflection and the aerodynamic force of any channel, Q δq is the cross term of the rigid body mode shape of the control surface deflection and the rigid body mode aerodynamic force of the full aircraft of any channel, Q qδ is the cross term of the rigid body mode shape of the full aircraft and the rigid body mode aerodynamic force of the control surface deflection of any channel, Q qq and Q δδ and Q δq and Q qδ are all 3×3 square matrices.

[0026] Based on the cross term Q qδ of the rigid body mode shape of the full aircraft and the rigid body mode aerodynamic force of the control surface deflection of any channel, the unsteady aerodynamic moment M' of each channel can be obtained. The unsteady aerodynamic moment M' can be calculated according to M' = q D Q qδ δ (calculated value), where q D Q qδ is the unsteady aerodynamic force, q D is the dynamic pressure based on the typical state points of the flight trajectory, Q qδ is the cross term of the rigid body mode shape of the full aircraft and the rigid body mode aerodynamic force of the control surface deflection of any channel, and δ is the deflection angle of any channel (unit angle, i.e., 1°).

[0027] Further, based on the aerodynamic force wind tunnel test data of the control surface, calculate and obtain the control force provided by the control surface per unit angle deflection to the aircraft in each channel, and calculate and obtain the control torque of each channel according to the control force provided by the control surface per unit angle deflection to the aircraft in each channel. The control force R of the aircraft can be calculated according to R = q D S ref c, where q D is the dynamic pressure based on the typical state points of the flight trajectory, S ref is the reference area of the control surface, and c is the control surface effectiveness. The control torque M of each channel can be calculated according to M = RLθ, where L is the mapping of the centroid distance of the control torque in any channel direction, and θ is the deflection angle of any channel.

[0028] After obtaining the unsteady aerodynamic torque of each channel and the control torque of each channel, the unsteady aerodynamic accuracy evaluation value of each channel can be calculated according to the unsteady aerodynamic torque of each channel and the control torque of each channel. Among them, the unsteady aerodynamic accuracy evaluation value E i of each channel can be calculated according to , where Ux is the roll channel, Uy is the yaw channel, and Uz is the pitch channel.

[0029] Further, after obtaining the unsteady aerodynamic accuracy evaluation value of each channel, compare the unsteady aerodynamic accuracy evaluation value of each channel with the set aerodynamic accuracy evaluation threshold range of the corresponding channel respectively. When the unsteady aerodynamic accuracy evaluation value of any channel exceeds the set aerodynamic accuracy evaluation threshold range of the corresponding channel, adjust the aerodynamic grid model of the whole aircraft, and repeat the above process until the unsteady aerodynamic accuracy evaluation value of any channel is within the set aerodynamic accuracy evaluation threshold range of the corresponding channel, and complete the evaluation and correction of the unsteady aerodynamic calculation accuracy.

[0030] To further understand the present invention, the following combines Figure 1 to elaborate in detail on the method for evaluating and correcting the unsteady aerodynamic calculation accuracy provided by the present invention.

[0031] As Figure 1 shown, according to a specific embodiment of the present invention, a method for evaluating and correcting the unsteady aerodynamic calculation accuracy is provided, and the method specifically includes the following steps.

[0032] Step 1, establish a full-aircraft dynamics model and a full-aircraft aerodynamic grid model. In the present invention, the full-aircraft dynamics finite model can be established by finite element software such as Hypermesh, MSC.patran, ANSYS, etc., and the full-aircraft aerodynamic grid model can be established by aerodynamic solution software such as ZAERO, MSC.flightloads, etc.

[0033] Step 2: Based on the full-aircraft dynamics model, construct the rigid-body mode shapes of the aircraft's rotation in the pitch, yaw, and roll channels and the rigid-body mode shapes of the control surface deflection. Specifically, in this embodiment, constructing the rigid-body mode shapes of the control surface deflection in the pitch, yaw, and roll channels of the aircraft specifically includes: According to the control surface control definitions in the pitch, yaw, and roll channels, construct the rigid-body mode shapes of the control surface deflection in the pitch, yaw, and roll channels of the aircraft. Among them, the control surface control definition is to define the deflection of each physical control surface for realizing the flight control of each channel, and the deflection of the control surface should specify positive and negative (for example: the vector direction along the control surface axis from the root chord to the tip chord is positive). Form a modal shape file of 3 + 3 orders based on the rigid-body mode shapes of the aircraft's rotation and the rigid-body mode shapes of the control surface deflection.

[0034] Step 3: Interpolate the rigid-body mode shapes of the aircraft's rotation in the three channels and the rigid-body mode shapes of the control surface deflection into the full-aircraft aerodynamic grid model. Compare the modal shapes of the interpolated full-aircraft aerodynamic grid model with the modal shapes before interpolation. When the difference between the modal shapes before and after interpolation is less than the preset difference, adjust the interpolation nodes, and repeat the above process until the difference between the modal shapes before and after interpolation is less than the preset difference. This method can effectively improve the interpolation quality.

[0035] Step 4: Select an applicable frequency-domain unsteady aerodynamic force solution method according to the typical state points of the flight trajectory. Using the frequency-domain unsteady aerodynamic force solution method, an unsteady aerodynamic force influence coefficient matrix (a 6×6 square matrix) at reduced frequency k = 0 can be obtained. Among them, Q is the unsteady aerodynamic force influence coefficient matrix at reduced frequency k = 0, Q qq is the self-interaction term of the rigid-body mode shape of the full-aircraft in any channel and the aerodynamic force, Q δδ is the self-interaction term of the rigid-body mode shape of the control surface deflection in any channel and the aerodynamic force, Q δq is the cross-term of the rigid-body mode shape of the control surface deflection in any channel and the aerodynamic force of the full-aircraft rigid body, Q qδ is the cross-term of the rigid-body mode shape of the full-aircraft in any channel and the aerodynamic force of the control surface deflection rigid body, Q qq 、Q δδ 、Q δq and Q qδ are all 3×3 square matrices. Based on the cross-term Q qδ of the rigid-body mode shape of the full-aircraft in any channel and the aerodynamic force of the control surface deflection rigid body, the unsteady aerodynamic moment M' of each channel can be obtained. The unsteady aerodynamic moment M' can be calculated according to M' = q D Q qδ δ (calculated value), where q D Q qδ is the unsteady aerodynamic force, qD is the dynamic pressure Q based on the typical state points of the flight trajectory qδ is the cross term of the rigid body mode shape of the entire aircraft and the aerodynamic force of the rigid body mode of the control surface deflection in any channel, and δ is the deflection angle of any channel (unit angle, that is, 1°). Step Five: Based on the control surface force measurement wind tunnel test data, combined with the control surface control definition (the control surface control definition is to define the rudder deflection of each physical control surface to achieve flight control of each channel, and the rudder deflection should specify positive and negative (for example: along the rudder axis, the vector direction from the root chord to the tip chord is positive)), calculate and obtain the control force provided by the control surface unit angle deflection to the aircraft in each channel, and calculate and obtain the control moment of each channel according to the control force provided by the control surface unit angle deflection to the aircraft in each channel. The control force R of the aircraft can be calculated and obtained according to R = q D S ref c (measured value), where q D is the dynamic pressure based on the typical state points of the flight trajectory, and S ref is the reference area of the control surface, and c is the rudder effectiveness. The control moment M of each channel at small angles (-10° to +10°) can be calculated and obtained according to M = RLθ, where L is the mapping of the centroid distance of the control moment in the direction of any channel, and θ is the deflection angle of any channel (unit angle, that is, 1°).

[0036] Step Six: Based on the fact that the unsteady aerodynamic force when the reduced frequency k = ωb / V (where ω is the circular frequency, b is the reference semi-chord length, and V is the flight speed) is 0 can be approximated as the quasi-steady aerodynamic force, calculate and obtain the unsteady aerodynamic force accuracy evaluation value of each channel according to the unsteady aerodynamic moment of each channel and the control moment of each channel. Each channel includes the pitch, yaw, and roll channels. Among them, the unsteady aerodynamic force accuracy evaluation value E i of each channel can be calculated and obtained according to , where Ux is the roll channel, Uy is the yaw channel, and Uz is the pitch channel.

[0037] Step 7: Based on the calculated values of the unsteady aerodynamic force accuracy assessment for each channel, which serve as an important basis for judging the accuracy of the aerodynamic grid model and further correction. Compare the unsteady aerodynamic force accuracy assessment values of each channel with the set threshold ranges of the aerodynamic force accuracy assessment for the corresponding channels respectively, that is, compare the unsteady aerodynamic force accuracy assessment value of the pitch channel with the set threshold range of the aerodynamic force accuracy assessment of the pitch channel, compare the unsteady aerodynamic force accuracy assessment value of the yaw channel with the set threshold range of the aerodynamic force accuracy assessment of the yaw channel, and compare the unsteady aerodynamic force accuracy assessment value of the roll channel with the set threshold range of the aerodynamic force accuracy assessment of the roll channel. When the unsteady aerodynamic force accuracy assessment value of any channel exceeds the set threshold range of the aerodynamic force accuracy assessment of the corresponding channel, adjust the aerodynamic grid model of the entire aircraft, and repeat the above process until the unsteady aerodynamic force accuracy assessment values of all channels are within the set threshold ranges of the aerodynamic force accuracy assessment of the corresponding channels, thus completing the accuracy assessment and correction of the unsteady aerodynamic force calculation. In this embodiment, the aerodynamic grid model can be corrected by considering the thickness of the aerodynamic airfoil, setting the connection between the aerodynamic surface and the airframe, adjusting the density of the aerodynamic grid, etc., until the unsteady aerodynamic force accuracy of the three channels meets the requirements.

[0038] In summary, the present invention provides a method for assessing and correcting the accuracy of unsteady aerodynamic force calculation. This method is based on the rudder effectiveness data (steady aerodynamic force data) obtained from the scaled model wind tunnel force measurement test of the aircraft control surface during the model development stage to assess and correct the accuracy of unsteady aerodynamic force calculation. It has been successfully applied to the work of assessing the accuracy of unsteady aerodynamic force calculation and correcting the aerodynamic grid model in multiple engineering models. The calculation method is simple and efficient. The assessment results provide support for the correction of the aerodynamic grid model and the results of aeroelastic dynamics analysis. The accuracy calculation values can be used as an important basis for judging and correcting the accuracy of the aircraft aerodynamic grid model, and can be widely applied to the accuracy assessment and correction of the numerical value of the unsteady aerodynamic force of the aircraft.

[0039] For ease of description, spatial relative terms such as "above", "over", "on the upper surface", "above" can be used here to describe the spatial position relationship between a device or feature shown in the figure and other devices or features. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation described in the figure for the device. For example, if the device in the figure is inverted, the device described as "above" or "over" other devices or structures will then be positioned "below" or "beneath" other devices or structures. Thus, the exemplary term "above" can include both the orientation of "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the corresponding explanations for the spatial relative descriptions used here will be made.

[0040] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Without additional declaration, the above terms have no special meaning, and thus should not be construed as a limitation on the protection scope of the present invention.

[0041] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for evaluating and correcting the calculation accuracy of unsteady aerodynamic forces, characterized in that, The method for evaluating and correcting the calculation accuracy of unsteady aerodynamic forces includes: Establishing a full-aircraft dynamics model and a full-aircraft aerodynamic grid model; Based on the full-aircraft dynamics model, constructing the rigid-body mode shapes of the aircraft's rotation in the pitch, yaw, and roll channels and the rigid-body mode shapes of the control surface deflection; Interpolating the rigid-body mode shapes of the aircraft's rotation in the three channels and the rigid-body mode shapes of the control surface deflection into the full-aircraft aerodynamic grid model; Based on the interpolated full-aircraft aerodynamic grid model, using the frequency-domain unsteady aerodynamic force solution method to calculate and obtain the unsteady aerodynamic forces of each channel of the aircraft; Calculating the unsteady aerodynamic moments of each channel according to the unsteady aerodynamic forces of each channel; Based on the control surface force measurement wind tunnel test data, calculating the control force provided to the aircraft by the unit angle deflection of the control surface in each channel, and calculating the control moment of each channel according to the control force provided to the aircraft by the unit angle deflection of the control surface in each channel; Calculating the evaluation value of the unsteady aerodynamic force accuracy of each channel according to the unsteady aerodynamic moment of each channel and the control moment of each channel; Comparing the evaluation values of the unsteady aerodynamic force accuracy of each channel with the set aerodynamic force accuracy evaluation threshold range of the corresponding channel respectively. When the evaluation value of the unsteady aerodynamic force accuracy of any channel exceeds the set aerodynamic force accuracy evaluation threshold range of the corresponding channel, adjusting the full-aircraft aerodynamic grid model, and repeating the above process until the evaluation values of the unsteady aerodynamic force accuracy of any channel are all within the set aerodynamic force accuracy evaluation threshold range of the corresponding channel, thus completing the evaluation and correction of the calculation accuracy of unsteady aerodynamic forces; When the flight trajectory is that of a subsonic aircraft, the dipole grid method is selected as the frequency-domain unsteady aerodynamic force solution method; when the flight trajectory is that of a low supersonic aircraft, the harmonic gradient method or the local flow piston theory is selected as the frequency-domain unsteady aerodynamic force solution method; when the flight trajectory is that of a high-speed aircraft, the unified lifting surface theory, the Van Dyke second-order piston theory, or the Newton impact theory is selected as the frequency-domain unsteady aerodynamic force solution method; The unsteady aerodynamic moment M' of each channel can be obtained according to M' = q D Q qδ δ, where q D is the dynamic pressure based on the typical state points of the flight trajectory, Q qδ is the cross term of the rigid body mode vibration shape of the whole aircraft and the aerodynamic force of the control surface deflection rigid body mode in any channel, and δ is the deflection angle of any channel; The cross-term Q between the rigid body mode shape of the entire aircraft in any channel and the aerodynamic force of the rigid body mode with the control surface deflection qδ can be obtained according to where Q is the unsteady aerodynamic influence coefficient matrix at the reduced frequency k = 0, and Q qq is the self-cross term between the rigid body mode shape of the entire aircraft in any channel and the aerodynamic force, and Q δδ is the self-cross term between the rigid body mode shape of the control surface deflection in any channel and the aerodynamic force, and Q δq is the cross-term between the rigid body mode shape of the control surface deflection in any channel and the aerodynamic force of the rigid body mode of the entire aircraft; The control force R of the aircraft can be obtained according to R = q D S ref c, where q D is the dynamic pressure based on the typical state points of the flight trajectory, S ref is the reference area of the control surface, and c is the rudder effectiveness; The control moment M of each channel can be calculated according to M = RLθ, where L is the mapping of the centroid distance of the control moment in the direction of any channel, and θ is the deflection angle of any channel; Unsteady aerodynamic accuracy evaluation value E for each channel i can be obtained according to where Ux is the roll channel, Uy is the yaw channel, and Uz is the pitch channel.

2. The method for evaluating and correcting the calculation accuracy of unsteady aerodynamic forces according to claim 1, characterized in that, After interpolating the rigid-body mode shapes of the aircraft's rotation in the three channels and the rigid-body mode shapes of the control surface deflection into the full-aircraft aerodynamic grid model, the method for evaluating and correcting the calculation accuracy of unsteady aerodynamic forces further includes: comparing the mode shape of the interpolated full-aircraft aerodynamic grid model with the mode shape before interpolation. When the difference between the mode shapes before and after interpolation is less than the preset difference, adjusting the interpolation nodes, and repeating the above process until the difference between the mode shapes before and after interpolation is less than the preset difference.

3. The method for evaluating and correcting the calculation accuracy of unsteady aerodynamic forces according to claim 1, characterized in that, Constructing the rigid body mode shapes of the control surface deflections in the pitch, yaw, and roll channels of the aircraft specifically includes: constructing the rigid body mode shapes of the control surface deflections in the pitch, yaw, and roll channels of the aircraft according to the control surface control definitions in the pitch, yaw, and roll channels.

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