A parameterized design method of a deceleration plate mechanism applied to a wide-range aircraft

Abstract

The application discloses a parameterized design method of a deceleration plate mechanism applied to a wide-range airplane, and comprises the following steps: determining a maximum resistance increment and a target resistance increment of the deceleration plate mechanism; determining a reference design parameter and a dynamic design parameter constraint condition, and constructing a resistance increment mathematical model based on a radial basis function; substituting the maximum resistance increment into the mathematical model, and constructing an optimization equation by taking the maximum value of a sub-plate extension length and a main plate opening angle as the constraint condition of the sub-plate extension length and the main plate opening angle, so as to obtain an optimal reference design parameter combination meeting the maximum resistance increment requirement; substituting the target resistance increment into the mathematical model, and constructing an optimization equation by taking the reference design parameter as the optimal reference design parameter, so as to obtain an optimal dynamic design parameter combination meeting the target resistance increment requirement; and simulating and verifying the optimal design parameter combination until the design is qualified, and finally outputting the design parameter. The application can realize wide-range adjustment of resistance, precise control of resistance error and wide-range airplane resistance increment requirement.

Description

Technical Field

[0001] This invention belongs to the field of aircraft design, specifically relating to a parametric design method for speed brake mechanisms applied to wide-range aircraft. Background Technology

[0002] As humanity continues to accelerate its exploration and utilization of space, and with increasing emphasis on near space, wide-area aircraft have become one of the important directions for the development of aerospace technology. To accomplish transport missions to near space and even orbital space, and to reduce takeoff requirements and costs, research on horizontal takeoff and landing, reusable wide-area aircraft has gradually become a hot topic.

[0003] To achieve horizontal takeoff and landing and reusability for wide-range aircraft, energy management during the landing phase is a critical aspect of ensuring safety. A well-designed energy management system can control landing speed, plan optimal landing trajectories, improve fuel efficiency, extend aircraft lifespan, and enhance flight quality.

[0004] During flight, speed brakes can adjust the energy consumption rate and assist in controlling the aircraft's attitude according to flight requirements. This is crucial for operations such as landing, aerial maneuvers, and emergency speed reduction in special circumstances. For wide-range aircraft, with their high flight speeds and narrow landing windows, the matching of speed brake performance with the overall aircraft drag adjustment requirements becomes particularly important. This necessitates a wide adjustment range and strong linear adjustment capability, while also minimizing interference with other aerodynamic parameters to ensure the safety of wide-range aircraft during landing. However, existing speed brake mechanism designs suffer from limitations in achieving wide-range drag adjustment and precise control of drag errors. Summary of the Invention

[0005] The purpose of this invention is to provide a parametric design method for speed brake mechanisms applied to wide-range aircraft, which can achieve wide-range drag adjustment, precise control of drag error, and meet the drag increase requirements of wide-range aircraft.

[0006] To achieve the above objectives, one aspect of the present invention provides a parametric design method for a speed brake mechanism applied to a wide-range aircraft, comprising:

[0007] Step S1: Determine the maximum drag increment and target drag increment of the speed brake mechanism. The speed brake mechanism is installed on the back of the aircraft fuselage and includes a main plate and a sub-plate. The main plate and the sub-plate are tightly attached to the back of the fuselage in the closed state and are designed to conform to the back of the fuselage. The main plate is located on the back of the fuselage and can be rotated relative to the back of the fuselage to open. In the open state, it forms a certain angle with the back of the fuselage. The sub-plate is located on the main plate and can be extended from the main plate by sliding on the main plate. By rotating the main plate and sliding the sub-plate, the frontal area of ​​the aircraft is increased, thereby increasing the drag.

[0008] Step S2: Determine the design parameter constraints. The design parameters include baseline design parameters and dynamic design parameters. The baseline design parameters are the main plate length, the width of the speed reducer mechanism, and the axial installation position of the speed reducer mechanism. The dynamic design parameters are the extension length of the sub-plate and the opening angle of the main plate. Sample and generate multiple sets of design parameter combinations. Obtain the resistance increment data corresponding to the multiple sets of design parameter combinations through simulation or experiment to form a sample dataset. Use the sample dataset as training samples and construct a surrogate model of resistance increment and design parameters based on radial basis functions as the mathematical model of resistance increment.

[0009] Step S3: Substitute the maximum resistance increment into the resistance increment mathematical model, and construct the first optimization equation by setting the extension length of the secondary plate and the opening angle of the main plate as the maximum values ​​of their constraints. Solve the first optimization equation using the particle swarm optimization algorithm to obtain the optimal combination of baseline design parameters that meets the maximum resistance increment requirement. Substitute the target resistance increment into the resistance increment mathematical model, and construct the second optimization equation by setting the baseline design parameters as the optimal baseline design parameters. Solve the second optimization equation using the dynamic design parameter constraints as the boundary to obtain the optimal combination of dynamic design parameters that meets the target resistance increment requirement.

[0010] Step S4: Perform simulation verification on the optimal design parameter combination, calculate the actual resistance increment. If the deviation between the actual resistance increment and the target resistance increment is below the first specified threshold, the design is qualified, and the final design parameters are output. If the deviation exceeds the first specified threshold, optimize the number of iterations of the particle swarm optimization algorithm, and repeat step S3 until the design is verified as qualified.

[0011] According to the parametric design method of the speed brake mechanism of the present invention, which is applied to wide-range aircraft, the parametric design method combining "baseline design" and "dynamic design" can achieve precise control of the drag error of the entire aircraft and meet the requirements of precise energy regulation under wide-range flight conditions. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort:

[0013] Figure 1 This is a side view of the deceleration plate mechanism of an embodiment of the present invention in the state where the secondary plate has not slid out.

[0014] Figure 2 This is a front view of the deceleration plate mechanism of an embodiment of the present invention in the state where the secondary plate is not slid out;

[0015] Figure 3 This is a side view of the deceleration plate mechanism in the sliding state according to an embodiment of the present invention;

[0016] Figure 4 This is a front view of the deceleration plate mechanism in the sliding state according to an embodiment of the present invention;

[0017] Figure 5 This is a schematic diagram of the leeward zone of the deceleration plate mechanism in the sliding state of an embodiment of the present invention.

[0018] Figure 6 This is a schematic diagram of the windward area of ​​the deceleration plate mechanism subplate in the sliding state according to an embodiment of the present invention;

[0019] Figure 7 This is a partially enlarged schematic diagram of the guide rail groove of a speed reducer mechanism according to an embodiment of the present invention;

[0020] Figure 8 This is a flowchart of a parametric design method for a speed reducer mechanism according to an embodiment of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0022] Wide-range aircraft are typically characterized by "low aspect ratio, thin airfoil" wings and "slender, thin fuselages," necessitating a compact and widely adjustable speed brake to mitigate drag during the unpowered return phase. Therefore, this invention designs a speed brake mechanism for wide-range aircraft, such as... Figures 1-7As shown, the speed reducer mechanism of this embodiment includes a back of the machine body 1, a main board 2, a secondary board 3, a main hydraulic rod 4, a secondary hydraulic rod 5, a guide rail groove 201 on the main board, and a guide rail strip 301 on the secondary board. The main board 2 is located on the back of the fuselage 1 and is connected by a hinge. The main board 2 can rotate around a fixed pivot. Two guide rail grooves 201 are symmetrically distributed on the main board 2, and two guide rails 301 are symmetrically distributed on the secondary board 3. The main board 2 and the secondary board 3 are connected by the guide rail grooves 201 and the guide rails 301. The secondary board 3 can slide along the guide rail grooves 201. When closed, the main board 2 and the secondary board 3 are tightly attached to the back of the fuselage and are designed to conform to the back of the fuselage 1. The main hydraulic rod 4 is fixed in the middle of the back of the main board 2 and provides the main power to drive the main board 2 to adjust its angle, so that the main board 2 forms an angle with the back of the fuselage, increasing the aircraft's frontal area and thus increasing drag to achieve a deceleration effect. The maximum angle is 60°. There are two secondary hydraulic rods 5, symmetrically placed on the back of the secondary board 3, which provide the main power to drive the secondary board 3 to slide along the guide rail grooves 201. As the secondary board 3 slides obliquely upward along the guide rail grooves 201, the extension length of the main board 2 gradually increases, thereby increasing the aircraft's frontal area and thus increasing drag to achieve a deceleration effect. The maximum extension length is 70% of the length of the main board 2. The guide rail groove 201 and the guide rail strip 301 are thinner in the middle and thicker at both ends, with one end being spherical. This ensures that the auxiliary plate 3 slides smoothly along the guide rail groove without any jamming or obstruction. At the same time, the sliding trajectory is precise, and the overall movement is stable and reliable, effectively improving the stability of the speed reducer.

[0023] The speed brake mechanism has a compact structure and can be installed on the "slender and thin" fuselage back of a wide-range aircraft. The speed brake's unfolding angle and length are adjustable, which can greatly expand the drag adjustment range. The guide rail 301, as a guide and load-bearing component for the movement of the sub-plate 3, can provide rigid support, effectively disperse the local stress concentration of the speed brake mechanism under aerodynamic load, suppress its bending and torsional deformation along the direction of movement, and improve the overall structural strength of the speed brake.

[0024] The mainboard 2 is made of high-strength, lightweight composite material, which has good toughness and high temperature resistance. Its shape design has been optimized by aerodynamics and is conformal to the aircraft fuselage. It can adjust the aircraft's frontal area by adjusting the opening and closing angle, thereby adjusting the drag.

[0025] Sub-plate 3 is made of high-strength, lightweight composite material, which has good toughness and high temperature resistance. Its shape design has been optimized by aerodynamics and is conformal to the aircraft fuselage. The extension length of the sub-plate can be adjusted when the main plate is deployed at a fixed angle, thereby adjusting the drag.

[0026] The main hydraulic rod 4 is used to drive the main board 2 to be lifted and unfolded at a certain angle, with the angle range being 0° to 60°.

[0027] The auxiliary hydraulic rod 5 pushes the auxiliary plate 3 out of the main plate 2, increasing the overall extension length of the speed reducer and thus increasing its frontal area. For structural strength considerations, the maximum increase in length is 70% of the main plate length.

[0028] The aerodynamic shape and installation position of the speed reducer mechanism in this embodiment of the invention have a total of five core design parameters. Three of them are baseline design parameters, which are completed during the aerodynamic layout design stage of the aircraft and cannot be dynamically designed and adjusted during flight. The other two are dynamic design parameters, which can be adaptively and dynamically designed during the operation of the aircraft, as follows:

[0029] Speed ​​brake mechanism width: denoted as W (unit: mm), refers to the maximum dimension of the speed brake mechanism along the transverse direction of the aircraft, and is a benchmark design parameter;

[0030] Speed ​​reducer mechanism length (main board length): denoted as L1 (unit: mm), refers to the length of the main body of the speed reducer (main board) along the axial direction of the aircraft, and is a benchmark design parameter;

[0031] Axial installation position of the speed reducer mechanism: denoted as X (unit: mm), which refers to the axial distance between the core mounting surface of the speed reducer mechanism and the reference origin of the aircraft, and is a reference design parameter;

[0032] Sub-plate extension length: denoted as L2 (unit: mm), refers to the extension length of the sub-plate relative to the main plate, which is a dynamic design parameter;

[0033] Mainboard opening angle: denoted as ρ (unit: °), refers to the angle between the speed brake and the surface of the aircraft after it is deployed, and is a dynamic design parameter.

[0034] The flow of the parametric design method for the speed reducer mechanism in this embodiment of the invention is as follows: Figure 8 As shown, it includes the following steps S1 to S4.

[0035] Step S1: Determine the maximum resistance increment and target resistance increment of the speed reducer mechanism.

[0036] The design input is the maximum resistance increment of the speed brake mechanism. and target resistance increment The maximum drag increment is determined by the aircraft's ultimate deceleration requirements and is used to design baseline parameters; the target drag increment is the difference between the target drag and the aircraft's current drag during flight, determined by the aircraft's current deceleration performance requirements and is used to design dynamic design parameters.

[0037] Step S2: Determine the design parameter constraints and construct the incremental resistance mathematical model.

[0038] Design constraints include motherboard length constraints. Width constraint of the speed reducer mechanism Installation location constraints Minimum motherboard length Maximum motherboard length Minimum speed reducer mechanism width Maximum speed reducer mechanism width Recent installation location and the furthest installation location Determined by the aerodynamic layout dimensions of the aircraft, and adapted to the aircraft's installation space; the extension length of the sub-plate is constrained. Motherboard opening angle constraints It is determined by engineering experience.

[0039] The following is a mathematical model for incremental resistance (based on the surrogate model method):

[0040] 1) Acquisition of training data for the surrogate model

[0041] Based on aerodynamic specifications and engineering experience, the value ranges of five design parameters were determined, and N sets of sample independent variable parameters (W) were determined using the orthogonal experimental method. i L 1i X i L 2i , ρ i (i=1,2,3……N, N≥50), ensuring that the sample parameters cover the entire range of parameter values. Then, through CFD (Computational Fluid Dynamics) aerodynamic simulation or wind tunnel ground tests, obtain the incremental data of the speed bump drag corresponding to multiple sets of design parameter combinations to form a sample dataset.

[0042] 2) Proxy model construction and fitting

[0043] Using the sample dataset as training samples, a radial basis function (RBF) surrogate model is used for fitting to construct a surrogate model of the speed bump drag increment and design parameters. The specific expression is as follows:

[0044]

[0045] In the formula:

[0046] This is the speed reducer resistance increment (i.e., the design output). Design parameter vector; To determine the number of basis functions in the surrogate model, take... (Same as the sample size); It is a Gaussian radial basis function. ,in The basis function shape parameters (ranging from 0.01 to 0.1, determined through cross-validation optimization) For the parameter vector to be determined and the first j The Euclidean distance between the parameter vectors of the group of samples; For the first j Group sample parameter vector; These are the coefficients of the basis functions; For polynomial compensation terms, a first-order polynomial is selected. Used to correct the fitting bias of the surrogate model. , , , , , These are the coefficients for each item.

[0047] 3) Proxy model verification and optimization

[0048] The accuracy of the constructed mathematical model is verified using leave-one-out cross-validation, and the verification error is calculated. The specific expression is as follows:

[0049]

[0050] In the formula,

[0051] The resistance increment is predicted using a surrogate model. For the drag increment obtained through aerodynamic simulation or wind tunnel ground testing, if If the model accuracy meets the design requirements, or if the error exceeds the standard, increase the number of samples or adjust the basis function type, and refit the surrogate model until the accuracy meets the requirements.

[0052] Step S3: Back-calculation of design parameters

[0053] The back-calculation of the baseline design parameters is based on the maximum drag increment. It is determined that the inverse calculation of dynamic design parameters is based on the target resistance increment. Sure.

[0054] The first step is the inverse calculation of the baseline design parameters. This involves calculating the maximum drag increment. Substitute this into the validated mathematical model of incremental resistance, and simultaneously let , Construct the first optimization equation: Using the baseline design parameter constraints as boundaries, the above optimization equations are solved using the particle swarm optimization algorithm to obtain the optimal combination of baseline design parameters that satisfies the maximum drag increment requirement. .

[0055] After the baseline design parameters are determined, the dynamic design parameters are back-calculated. The target resistance increment is then calculated. Substitute this into the validated mathematical model of incremental resistance, and simultaneously let , , Construct the optimization equation: Using dynamic design parameter constraints as boundaries, the particle swarm optimization algorithm is employed to solve the above optimization equations, yielding the optimal combination of dynamic design parameters that satisfies the target resistance increment requirement. .

[0056] Step S4: Design Verification and Iteration

[0057] For the optimal combination of design parameters Perform CFD aerodynamic simulation to verify and calculate the actual drag increment. ;like If the design is successful, output the final design parameters; if the deviation exceeds the standard, optimize the algorithm iteration count and recalculate the design parameters until the verification is successful.

[0058] In summary, the parametric design method for speed brake mechanisms applied to wide-range aircraft according to the embodiments of the present invention has the following beneficial effects: By combining a surrogate model, a precise mathematical correlation between drag increment and design parameters is established, enabling quantitative back-calculation of design parameters and improving the design accuracy of the speed brake; the design constraints and iterative verification process are clarified, ensuring that the design results match the structural space and deceleration performance requirements of the aircraft, reducing design redundancy; the process is standardized and reproducible, applicable to the aerodynamic design of speed brakes for different types of aircraft, improving design efficiency and shortening the development cycle; the designed speed brake mechanism has a compact structure, can be applied to the drag increase requirements of wide-range aircraft, and allows for independent adjustment of the speed brake angle and length in two dimensions, adapting to wide-range flight.

[0059] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A parametric design method for speed brake mechanisms applied to wide-range aircraft, characterized in that, include: Step S1: Determine the maximum drag increment and target drag increment of the speed brake mechanism. The speed brake mechanism is installed on the back of the aircraft fuselage and includes a main plate and a sub-plate. The main plate and the sub-plate are tightly attached to the back of the fuselage in the closed state and are designed to conform to the back of the fuselage. The main plate is located on the back of the fuselage and can be rotated relative to the back of the fuselage to open. In the open state, it forms a certain angle with the back of the fuselage. The sub-plate is located on the main plate and can be extended from the main plate by sliding on the main plate. By rotating the main plate and sliding the sub-plate, the frontal area of ​​the aircraft is increased, thereby increasing the drag. Step S2: Determine the design parameter constraints. The design parameters include baseline design parameters and dynamic design parameters. The baseline design parameters are the main plate length, the width of the speed reducer mechanism, and the axial installation position of the speed reducer mechanism. The dynamic design parameters are the extension length of the sub-plate and the opening angle of the main plate. Sample and generate multiple sets of design parameter combinations. Obtain the resistance increment data corresponding to the multiple sets of design parameter combinations through simulation or experiment to form a sample dataset. Use the sample dataset as training samples and construct a surrogate model of resistance increment and design parameters based on radial basis functions as the mathematical model of resistance increment. Step S3: Substitute the maximum resistance increment into the resistance increment mathematical model, and construct the first optimization equation by setting the extension length of the secondary plate and the opening angle of the main plate as the maximum values ​​of their constraints. Solve the first optimization equation using the particle swarm optimization algorithm to obtain the optimal combination of baseline design parameters that meets the requirements of the maximum resistance increment. Substitute the target resistance increment into the resistance increment mathematical model, set the baseline design parameters as the optimal baseline design parameters to construct the second optimization equation, use the dynamic design parameter constraints as the boundary, and use the particle swarm optimization algorithm to solve the second optimization equation to obtain the optimal dynamic design parameter combination that meets the target resistance increment requirement. Step S4: Perform simulation verification on the optimal design parameter combination, calculate the actual resistance increment, and if the deviation between the actual resistance increment and the target resistance increment is below the first specified threshold, the design is qualified and the final design parameters are output. If the deviation exceeds the first specified threshold, the number of iterations of the particle swarm optimization algorithm is optimized, and step S3 is repeated until the design is verified to be qualified. The mathematical model for incremental resistance is: in, As the increase in resistance, To design the parameter vector, The width of the speed reducer mechanism, For motherboard length, This refers to the axial mounting position of the speed reducer mechanism. The length of the secondary plate extension. Open the angle for the motherboard. The number of basis functions in the surrogate model. It is a Gaussian radial basis function. ,in The basis function shape parameters, For the parameter vector to be determined and the first j The Euclidean distance between the parameter vectors of the group of samples. For the first j Group sample parameter vector, These are the coefficients of the basis functions. It is a polynomial compensation term. Used to correct the fitting bias of the surrogate model. , , , , , These are the coefficients for each item.

2. The method as described in claim 1, characterized in that, Between steps S2 and S3, the following steps are also included: verifying the accuracy of the incremental resistance mathematical model through leave-one-out cross-validation, calculating the verification error, and if the verification error is below the second specified threshold, the model accuracy meets the design requirements; otherwise, the number of samples is increased or the basis function type is adjusted, and the surrogate model is refitted until the accuracy meets the requirements.

3. The method as described in claim 2, characterized in that, Verification error The expression is: in, The resistance increment is predicted using a surrogate model. N represents the drag increment obtained through aerodynamic simulation or wind tunnel ground testing, and N is the number of samples.

4. The method according to any one of claims 1-3, characterized in that, Sub-plate extension length The constraints are Its maximum value is 70% of the motherboard length, and the constraint condition for the motherboard opening angle ρ is: Its maximum value is 60 degrees.

5. The method as described in claim 4, characterized in that, The first optimization equation is: ,in, This represents the maximum resistance increment. The second optimization equation is: ,in, The target is the increase in resistance.

6. The method according to any one of claims 1-3, characterized in that, The motherboard is connected to the back of the chassis via a hinge. Two guide rails are symmetrically arranged on the motherboard, and two guide rails are symmetrically arranged on the sub-board. The motherboard and the sub-board are connected via the guide rails and guide rails, and the sub-board can slide along the guide rails on the motherboard.

7. The method as described in claim 6, characterized in that, The speed reducer mechanism also includes a main hydraulic rod and an auxiliary hydraulic rod. The main hydraulic rod is fixed in the middle of the back of the main board and is used to drive the main board to be supported so that the main board and the back of the machine body form a certain angle. There are two auxiliary hydraulic rods, which are symmetrically arranged on the back of the auxiliary plate and are used to drive the auxiliary plate to slide along the guide rail groove and extend out from the main board.

8. The method as described in claim 7, characterized in that, The motherboard and sub-board are made of high-strength and lightweight composite materials.

9. The method according to any one of claims 1-3, characterized in that, Both the first and second specified thresholds are 5%.

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