A method for evaluating the heading controllability of a tailless aircraft

Abstract

This invention relates to a method for evaluating the directional controllability of a tailless aircraft, belonging to the field of aircraft evaluation technology. It includes: acquiring aircraft parameters related to heading; setting the evaluation state point; obtaining the heading-inertial coupling index based on the formula for calculating the derivative of the yaw rate; calculating the directional finite-time convergence index based on the sideslip angle dynamic equation and reasonable assumptions; comparing the absolute values ​​of the maximum remaining directional moment coefficient with the directional-inertial coupling index and the directional finite-time convergence index to determine whether the aircraft layout satisfies both the directional-inertial coupling index and the directional controllability index. This invention relies on the most basic mechanical equations to design the directional controllability index, requiring only a few simple aircraft parameters for evaluation. It is versatile and can accurately evaluate a new aircraft layout under various conditions and within a short timeframe.

Description

Technical Field

[0001] This invention belongs to the field of aircraft evaluation technology, specifically relating to a method for evaluating the heading controllability of a tailless aircraft. Background Technology

[0002] Tailless aircraft, in order to balance requirements such as stealth, high lift-to-drag ratio, and supersonic high-maneuverability flight, adopt a blended wing-body configuration, eliminating the vertical tail and simultaneously relaxing static stability in both longitudinal and directional directions. This results in directional instability, weak controllability, and long control surface travel. The controllability, flight control bottom edge, and control capabilities of tailless aircraft require quantitative assessment. When collaborating with overall professionals to iterate on solutions, rapid, easily understood, and evidence-based professional feedback is essential.

[0003] Existing evaluation metrics are inadequate for assessing the new layout, and six-degree-of-freedom simulations can only cover a limited range of states. Summary of the Invention

[0004] The technical problem to be solved by this invention is:

[0005] To avoid the shortcomings of the prior art, the present invention provides a method for evaluating the heading controllability of a tailless aircraft, including an inertial coupling index and a heading finite-time recovery index.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A method for evaluating the heading controllability of a tailless aircraft, characterized by comprising:

[0008] Obtain aircraft parameters related to heading, including: moment of inertia, wing area, and wingspan;

[0009] Set the evaluation state points, including dynamic pressure point, angle of attack, Mach number, maximum allowable sideslip angle, allowable convergence time for sideslip angle, and maximum allowable inertial coupling.

[0010] The yaw rate derivative is used to calculate the yaw rate inertial coupling index, which involves the mass moment of inertia, wing area, wingspan, dynamic pressure point, and maximum allowable inertial coupling.

[0011] Based on the sideslip angle dynamic equation, a finite-time convergence index for the heading is obtained through reasonable assumptions. The sideslip angle dynamic equation involves the angle of attack.

[0012] By consulting the aircraft aerodynamics library of the layout scheme, and obtaining the body yaw moment coefficient and the maximum directional control moment coefficient based on the angle of attack, Mach number, and maximum permissible sideslip angle at the evaluation point, the maximum residual directional moment coefficient can be obtained.

[0013] By comparing the absolute values ​​of the maximum remaining heading moment coefficient with the heading inertia coupling index and the heading finite-time convergence index, it is determined whether the aircraft layout scheme satisfies the heading inertia coupling index and the heading controllability index.

[0014] A further technical solution of the present invention: the calculation formula for the heading inertial coupling index is as follows:

[0015]

[0016] Among them, C Npq I represents the heading-inertial coupling index. x I y These represent the components of the moment of inertia along the x and y axes, respectively. To evaluate the dynamic pressure point, S is the wing area, b is the wingspan, and (pq) max To allow the maximum amount of inertial coupling.

[0017] A further technical solution of the present invention: the calculation formula for the finite-time convergence index is as follows:

[0018]

[0019] Among them, I z β represents the z-axis component of the mass moment of inertia. max To evaluate the maximum permissible sideslip angle, To evaluate the dynamic pressure point, T is the allowable convergence time for the sideslip angle, and α is the angle of attack at the evaluation point.

[0020] A further technical solution of the present invention: the maximum remaining heading moment coefficient is specifically as follows:

[0021] C Nrm =C Ndr -C Nbeta

[0022] Among them, C Nbeta To evaluate the point-body yaw moment coefficient, C Ndr C is the maximum heading control moment coefficient. Nrm This is the maximum remaining heading moment coefficient.

[0023] A further technical solution of the present invention: the specific steps for determining whether the aircraft layout scheme meets the heading-inertial coupling index and the heading controllability index are as follows:

[0024] If the absolute value of the maximum remaining heading moment coefficient is less than the absolute value of the heading inertial coupling index or the absolute value of the heading finite-time convergence index, then the aircraft layout scheme does not meet the heading inertial coupling index and the heading controllability index.

[0025] If the absolute value of the maximum remaining heading moment coefficient is greater than the absolute value of the heading inertial coupling index and the absolute value of the heading finite-time convergence index, then the aircraft layout scheme satisfies the heading inertial coupling index and the heading controllability index.

[0026] A computer system is characterized by comprising: one or more processors, and a computer-readable storage medium for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement the method described above.

[0027] A computer-readable storage medium is characterized by storing computer-executable instructions, which, when executed, are used to implement the above-described method.

[0028] The beneficial effects of this invention are as follows:

[0029] This invention provides a method for evaluating the directional controllability of tailless aircraft. Based on the most fundamental equations of mechanics, it designs directional controllability indices that require only a few simple aircraft parameters for evaluation. This method is versatile and allows for accurate evaluation of new aircraft layouts under various conditions and within a short timeframe. This invention has already been applied to the controllability evaluation of new aircraft layouts and provides quantitative feedback on scheme iteration to overall engineering professionals. Attached Figure Description

[0030] The accompanying drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like parts throughout the drawings.

[0031] Figure 1 Flowchart of the method of this invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0033] The present invention provides a method for evaluating the heading controllability of a tailless aircraft. Based on the most basic mechanical equations, it only requires a few simple parameters of the aircraft for evaluation. It is versatile and can accurately evaluate a new round of aircraft layouts in a variety of states and within a short period of time.

[0034] like Figure 1 As shown, it includes the following steps:

[0035] Step 1: Obtain the mass moment of inertia I of the aircraft with the layout scheme x Iy I z Wing area S, wingspan b;

[0036] Step 2: Set the evaluation dynamic pressure point q, the evaluation point angle of attack α, the evaluation point Mach number M, and the evaluation point maximum allowable sideslip angle β. max Sideslip angle, allowable convergence time T, and allowable maximum inertial coupling (pq). max ;

[0037] Step 3: Yaw rate derivative The calculation formula is as follows:

[0038]

[0039] Where: C N C represents the yaw moment coefficient. Npq C represents the heading-inertial coupling index. Npq The calculation formula is as follows:

[0040]

[0041] Step 4: Develop the finite-time convergence index for the navigation direction. The original dynamic equation for the sideslip angle is as follows:

[0042]

[0043] Where V is the aircraft speed, A xm 、A ym and A zm The values ​​represent triaxial acceleration, θ is the pitch angle, β is the sideslip angle, φ is the roll angle, r is the yaw rate, and p is the roll rate.

[0044] The following assumptions are considered when deriving the evaluation indicators:

[0045] Assumption 1: Ignore maneuver coupling, i.e., p = q = 0; q represents pitch rate;

[0046] Assumption 2: The roll angle of the aircraft is not considered, i.e., φ = 0;

[0047] Assumption 3: The tailless layout neglects lateral forces, i.e., the lateral force coefficient C Y It is zero, and other small quantities are ignored.

[0048] The dynamic equation for the sideslip angle then simplifies to:

[0049]

[0050] in, Represents the derivative of the sideslip angle;

[0051] There are also

[0052]

[0053] Then the backslip angle at time T is:

[0054]

[0055] Given the maximum evaluated sideslip angle β max The finite-time convergence index C of the heading is calculated using the following formula. Nmax

[0056]

[0057] Step 5: Consult the aircraft aerodynamics library for layout schemes, based on β max α and M are used to obtain the yaw moment coefficient C of the body at the evaluation point. Nbeta Maximum heading control moment coefficient C Ndr Then the maximum residual heading moment coefficient C Nrm The calculation method is as follows:

[0058] C Nrm =C Ndr -C Nbeta

[0059] Step Six: Compare C Nrm With C Npq C Nmax The magnitude of the absolute value, if C Nrm The absolute value is less than C Npq Absolute value or C Nmax If the absolute value is not met, then the aircraft layout scheme does not satisfy the heading-inertia coupling index and the heading controllability index; if C Nrm The absolute value is greater than C Npq Absolute value and C Nmax If the absolute value is obtained, then the aircraft layout scheme satisfies the heading-inertial coupling index and the heading-finite-time convergence index.

[0060] Example 1:

[0061] For a certain type of tailless aircraft, the takeoff point is selected as the evaluation point to evaluate its finite-time convergence index for heading. The evaluation steps are as follows:

[0062] 1) Evaluation point Vc = 245 km / h (dynamic pressure 292 kg / m^2), β max Selecting 12 degrees, the aircraft's mass-moment characteristics are as follows:

[0063]

[0064] 2) The convergence time T is set to 2.5 seconds (the standard time requirement for D-Crab).

[0065] 3) The required residual torque capacity C obtained through step four. Nmax The value is 0.0056. According to the aerodynamic database, the maximum residual control effect C of the cracked rudder for this type of aircraft at a 12° angle of attack is... Nrm It is 0.0121, which is greater than C. Nmax If the heading is within a certain range, then the aircraft satisfies the finite-time convergence index.

[0066] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the scope of the technology disclosed in the present invention, and such modifications or substitutions should all be covered within the scope of protection of the present invention.

Claims

1. A method for evaluating the heading controllability of a tailless aircraft, characterized in that, include: Obtain aircraft parameters related to heading, including: moment of inertia, wing area, and wingspan; Set the evaluation state points, including dynamic pressure point, angle of attack, Mach number, maximum allowable sideslip angle, allowable convergence time for sideslip angle, and maximum allowable inertial coupling. The directional inertial coupling index is obtained based on the formula for calculating the derivative of the yaw rate. The formula for calculating the derivative of the yaw rate involves the mass moment of inertia, wing area, wingspan, dynamic pressure point, and the maximum permissible inertial coupling. The formula for calculating the directional inertial coupling index is as follows: in, Indicates the heading-inertial coupling index. , Representing the moment of inertia of the mass at... x , y Axial components, To assess the dynamic pressure point, For wing area, For wingspan, To allow the maximum amount of inertial coupling; Based on the sideslip angle dynamic equation, a finite-time convergence index for the heading is obtained through assumptions and calculations. The sideslip angle dynamic equation involves the angle of attack. The formula for calculating the finite-time convergence index is as follows: in, Indicates the moment of inertia of mass in z Axial components, To evaluate the maximum permissible sideslip angle, To assess the dynamic pressure point, The allowable convergence time is the sideslip angle. Angle of attack at the evaluation point; By consulting the aircraft aerodynamics library of the layout scheme, and obtaining the body yaw moment coefficient and the maximum directional control moment coefficient based on the angle of attack, Mach number, and maximum permissible sideslip angle at the evaluation point, the maximum residual directional moment coefficient can be obtained. By comparing the absolute values ​​of the maximum remaining heading moment coefficient with the heading inertia coupling index and the heading finite-time convergence index, it is determined whether the aircraft layout scheme satisfies the heading inertia coupling index and the heading controllability index.

2. The method for evaluating the heading controllability of a tailless aircraft according to claim 1, characterized in that, The maximum remaining heading moment coefficient is specifically: in, To evaluate the point body yaw moment coefficient, This is the maximum control moment coefficient for the heading. This is the maximum remaining heading moment coefficient.

3. The method for evaluating the heading controllability of a tailless aircraft according to claim 1, characterized in that, The specific steps for determining whether the aircraft layout scheme meets the heading-inertial coupling index and the heading controllability index are as follows: If the absolute value of the maximum remaining heading moment coefficient is less than the absolute value of the heading inertial coupling index or the absolute value of the heading finite-time convergence index, then the aircraft layout scheme does not meet the heading inertial coupling index and the heading controllability index. If the absolute value of the maximum remaining heading moment coefficient is greater than the absolute value of the heading inertial coupling index and the absolute value of the heading finite-time convergence index, then the aircraft layout scheme satisfies the heading inertial coupling index and the heading controllability index.

4. A computer system, characterized in that... include: One or more processors, a computer-readable storage medium for storing one or more programs, wherein, when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement the method of claim 1.

5. A computer-readable storage medium, characterized in that... The device stores computer-executable instructions, which, when executed, are used to implement the method of claim 1.

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