阅读说明：本技术 一种大型货运无人机着陆构型及其设计方法 (Landing configuration of large-scale freight unmanned aerial vehicle and design method thereof ) 是由 汪善武 刘泽峰 毕培信 常天星 王富贵 于 2021-08-13 设计创作，主要内容包括：本发明公开了一种大型货运无人机着陆构型及其设计方法,所述大型货运无人机的主翼设有多级襟翼,多级襟翼包括襟翼主片和襟翼滑片,襟翼主片设有凹槽,所述襟翼滑片设有凸轨,所述襟翼主片与襟翼滑片通过凹槽和凸轨连接,所述襟翼主片和襟翼滑片接触面径向切面为直线或者弧形,所述襟翼滑片可沿着襟翼主片的凹槽进行滑动,构成所述多级襟翼的所述襟翼滑片与襟翼主片有三种位置连接方式,多级襟翼通过三种位置连接方式和四种偏角卡位,构成12种多级襟翼位置构型,并根据大型货运无人机的实际载重情况,选择适合的襟翼构型,对大型货运无人机安全着陆有着重要意义。(The invention discloses a landing configuration of a large freight unmanned aerial vehicle and a design method thereof, wherein a main wing of the large freight unmanned aerial vehicle is provided with a multi-stage flap, the multi-stage flap comprises a flap main sheet and a flap sliding sheet, the flap main sheet is provided with a groove, the flap sliding sheet is provided with a convex rail, the flap main sheet is connected with the flap sliding sheet through a groove and the convex rail, the radial tangent plane of the contact surface of the flap main sheet and the flap sliding sheet is a straight line or an arc, the flap sliding sheet can slide along the groove of the flap main sheet, the flap sliding sheet and the flap main sheet which form the multi-level flap have three position connection modes, the multi-level flap forms 12 multi-level flap position configurations through three position connection modes and four deflection angle screens, and according to the actual load condition of the large-scale freight unmanned aerial vehicle, a proper flap configuration is selected, and the method has important significance for the safe landing of the large-scale freight unmanned aerial vehicle.)

1. The utility model provides a large-scale freight transportation unmanned aerial vehicle landing configuration, its characterized in that, landing configuration is equipped with the multistage flap, the multistage flap includes flap main leaf and flap gleitbretter, the flap main leaf is equipped with the recess, the flap gleitbretter is equipped with the tongue, the flap main leaf passes through recess and tongue with the flap gleitbretter to be connected, flap main leaf and flap gleitbretter contact surface radial tangent plane are sharp or arc, the flap gleitbretter can slide along the recess of flap main leaf.

2. The landing configuration of large-scale freight unmanned aerial vehicle according to claim 1, wherein the flap slide sheet and the flap main sheet which form the multi-stage flap have three position connection modes, namely a "0 position", a "1 position" and a "2 position", the "0 position" is a non-dislocation clamping mode, the "1 position" and the "2 position" are dislocation clamping modes, and the dislocation degree of the "2 position" is greater than that of the "1 position".

3. The landing configuration for a large-scale cargo unmanned aerial vehicle, according to claim 2, wherein the multi-stage flap has four drift angle positions, i, ii, iii and iv drift angle positions, wherein the drift angle position i is 0 °, the drift angle position ii is 10 °, the drift angle position iii is 20 ° and the drift angle position iv is 30 °.

4. The landing configuration of a large-scale cargo unmanned aerial vehicle according to claim 3, wherein the multi-level flaps form 12 multi-level flap position configurations through the drift angle blocking positions and three position connection modes, and the position configurations are respectively 0I, 0 II, 0 III and 0 IV corresponding to four drift angle blocking positions at the time of "0 position", and the position configurations are respectively 1I, 1 II, 1 III and 1 IV corresponding to four drift angle blocking positions at the time of "1 position", and the position configurations are respectively 2I, 2 II, 2 III and 2 IV corresponding to four drift angle blocking positions at the time of "2 position".

5. A design method for a landing configuration of a large-scale freight unmanned aerial vehicle as claimed in any one of claims 1-4, comprising the following steps:

(1) determining main wing and flap wing profiles;

(2) the flow field adopts a C-H type network topological structure;

(3) performing aerodynamic calculation on different position configurations of the flaps by using a pressure correction algorithm;

(4) and determining the position configuration of the corresponding multi-stage flap of the large-scale freight unmanned aerial vehicle during landing under different loading conditions according to the calculation result.

6. The method according to claim 5, wherein the pressure correction algorithm of step (3) is implemented in a windward format.

7. The method as claimed in claim 5, wherein the pressure correction algorithm in step (3) is solved by using Runge-Kutta method.

8. The method for designing the landing configuration of the large-scale freight unmanned aerial vehicle according to claim 5, wherein the pressure correction algorithm in the step (3) adopts a simple method for coupling the pressure and the speed, and the difference format adopts a second-order windward format.

9. The method of claim 5, wherein the position configuration of step (4) is one of the 12 multi-level flap position configurations.

Technical Field

The invention belongs to the technical field of landing control of large-scale cargo conveyers, and particularly relates to a landing configuration of a large-scale cargo unmanned aerial vehicle and a design method thereof.

Background

In the landing process of the airplane, due to the fact that the speed of the airplane is reduced, the flying configuration of the airplane needs to be adjusted correspondingly, and due to the fact that the weight difference of the large-sized freight unmanned aerial vehicle before and after loading is large, particularly in the process of returning to landing after automatic air drop and unloading, more landing configuration choices need to be provided for the large-sized freight unmanned aerial vehicle in order to ensure landing safety of the large-sized freight unmanned aerial vehicle.

Disclosure of Invention

The invention aims to provide a landing configuration of a large-scale freight unmanned aerial vehicle and a design method thereof, which provide more landing configuration choices for the large-scale freight unmanned aerial vehicle and have important significance for landing safety of the large-scale freight unmanned aerial vehicle.

In order to achieve the purpose, the invention adopts the following technical scheme:

the utility model provides a large-scale freight transportation unmanned aerial vehicle landing configuration, its characterized in that, large-scale freight transportation unmanned aerial vehicle is equipped with the multistage wing flap, the multistage wing flap includes wing flap main leaf and wing flap gleitbretter, the wing flap main leaf is equipped with the recess, the wing flap gleitbretter is equipped with the tongue, the wing flap main leaf passes through recess and tongue with the wing flap gleitbretter to be connected, wing flap main leaf and wing flap gleitbretter contact surface radial tangent plane are sharp or arc, the wing flap gleitbretter can slide along the recess of wing flap main leaf.

Furthermore, the flap sliding blade and the flap main blade which form the multistage flap have three position connection modes, namely a '0 position', a '1 position' and a '2 position', the '0 position' is in dislocation-free clamping connection, the '1 position' and the '2 position' are in dislocation clamping connection, and the dislocation degree of the '2 position' is greater than that of the '1 position';

furthermore, the multi-stage flap has four drift angle screens, namely, a drift angle screen I, a drift angle screen II, a drift angle screen III and a drift angle screen IV, wherein the drift angle screen I is 0 degree, the drift angle screen II is 10 degrees, the drift angle screen III is 20 degrees, and the drift angle screen IV is 30 degrees.

Furthermore, the multi-stage flap is connected in three positions through the drift angle screens to form 12 multi-stage flap position configurations, wherein in the case of a 0 position, the multi-stage flap corresponds to four drift angle screens which are respectively in 0I, 0 II, 0 III and 0 IV position configurations, in the case of a 1 position, the multi-stage flap corresponds to four drift angle screens which are respectively in 1I, 1 II, 1 III and 1 IV position configurations, and in the case of a 2 position, the multi-stage flap corresponds to four drift angle screens which are respectively in 2I, 2 II, 2 III and 2 IV position configurations.

The landing configuration of the large-scale freight unmanned aerial vehicle comprises the following steps:

(1) determining main wing and flap wing profiles;

(2) the flow field adopts a C-H type network topological structure;

(3) performing aerodynamic calculation on different position configurations of the flaps by using a pressure correction algorithm;

(4) and determining the position configuration of the corresponding multi-stage flap of the large-scale freight unmanned aerial vehicle during landing under different loading conditions according to the calculation result.

Further, in the pressure correction algorithm in the step (3), the discrete format adopts an upwind format for performing the discrete.

Further, the pressure correction algorithm in the step (3) adopts a Runge-Kutta method to solve the time integral.

Further, the pressure correction algorithm in the step (3) adopts a simple method to couple pressure and speed, and the differential format adopts a second-order windward format.

Further, the position configuration in the step (4) is one of the 12 multi-level flap position configurations.

The invention has the following beneficial effects:

1) compared with the traditional single-flap configuration, the novel multi-level flap has the characteristic of large adjustable space, experiments prove that the configuration is simple and reliable, the lift coefficient can be effectively improved, more flap configurations are provided for the multi-level flap through the change of the relative positions of the flap main sheet and the flap sliding sheet, and the multi-level flap provided by the invention can be further proved through calculation and wind tunnel tests, the change range of the lift coefficient can be effectively improved, more landing configuration choices are provided for a large-sized freight unmanned aerial vehicle, and the characteristic of large weight difference before and after loading of the large-sized freight unmanned aerial vehicle is realized, and the landing safety of the large-sized freight unmanned aerial vehicle can be greatly improved through different configurations of the multi-level flap;

2) the comparison of wind tunnel tests and the lift coefficient curve of the calculation result shows that the aerodynamic analysis and calculation method disclosed by the invention can well simulate and calculate the lift coefficient, and has important revelation and reference significance on the flap aerodynamic analysis and research method.

Drawings

FIG. 1: a multi-stage flap schematic for a large-cargo drone landing configuration;

FIG. 2: a schematic view of a multi-stage flap radial section of a landing configuration of a large-sized cargo-freight unmanned aerial vehicle;

FIG. 3: a schematic diagram of a transverse cross-section of a multi-stage flap for a landing configuration of a large-sized cargo drone;

FIG. 4: a schematic diagram of connection modes of three horizontal positions of a multi-stage flap of a landing configuration of a large-scale freight unmanned aerial vehicle;

FIG. 5: a first schematic diagram of a lift coefficient curve of a landing configuration of a large-scale freight unmanned aerial vehicle;

FIG. 6: a schematic diagram II of a lift coefficient curve of a landing configuration of a large-scale freight unmanned aerial vehicle;

FIG. 7: a third schematic diagram of a lift coefficient curve of a landing configuration of a large-scale freight unmanned aerial vehicle;

FIG. 8: a lift coefficient curve diagram of a landing configuration of a large-scale freight unmanned aerial vehicle is shown as IV;

FIG. 9: a lift coefficient curve diagram of a landing configuration of a large-scale freight unmanned aerial vehicle is shown as five;

the names of the reference symbols in the drawings are as follows: 1-flap main sheet, 2-flap sliding sheet, 3-convex rail and 4-groove.

Detailed Description

The technical scheme of the patent is further explained by combining the attached drawings and the embodiment.

Example 1

As shown in fig. 1, a first multi-stage flap of a landing configuration of a large-scale cargo unmanned aerial vehicle comprises a flap main sheet 1 and a flap sliding sheet 2, wherein the flap main sheet 1 and the flap sliding sheet 2 are in contact and joint together, as shown in fig. 2, a first multi-stage flap radial section schematic view of the landing configuration design of the large-scale cargo unmanned aerial vehicle is provided with a groove 4, the flap main sheet is provided with a raised track 3, the flap main sheet and the flap sliding sheet are connected with the raised track 3 through the groove 4, the radial section of the contact surface of the flap main sheet 1 and the flap sliding sheet 2 is a straight line or an arc, and the schematic view of the embodiment is a part of an arc, is set to be an arc or a straight line, and aims at enabling the flap sliding sheet to slide along the groove of the flap main sheet.

As shown in figure 3, a schematic diagram of a transverse cross section of a multi-level flap designed for a landing configuration of a large-sized cargo unmanned aerial vehicle, a flap main sheet 1 and a flap sliding sheet 2 are buckled together through a groove 4 and a convex rail 3 to form a stable movable link state.

As shown in fig. 4, a schematic diagram of connection modes of three transverse positions of a multi-level flap in a landing configuration design of a large-scale cargo unmanned aerial vehicle, the flap sliding blade and the flap main blade of the multi-level flap have three connection modes, fig. 4 is a schematic diagram of the flap sliding blade and the flap main blade clamped at a "0 position", a "1 position" and a "2 position" from top to bottom, the "0 position" is a non-dislocation clamping, the "1 position" and the "2 position" are dislocation clamping, and the dislocation degree of the "2 position" is greater than the "1 position".

Example 2

Selecting a main wing NACA65-205 airfoil profile, and configuring the multi-level flap of the invention aiming at the NACA65-205 airfoil profile, wherein the main wing NACA65-205 airfoil profile comprises the following components: NACA 650I position configuration, NACA 650 II position configuration, NACA 650 III position configuration, NACA 650 IV position configuration. The attack angle range is 0-12 degrees, the interval is 2 degrees, and the aerodynamic characteristics of 7 points are totally obtained.

The numerical simulation adopts a structural grid, C-HThe type grid is taken as the leading factor, the far-field boundary of the calculation domain is taken as 120 times of chord length, and the first row of grids positioned on the wall surface is 1.0 multiplied by 10^-7And the grids are encrypted at the wing seams, boundary layers, trail regions and the like to capture the slight change of the flow field and ensure the numerical simulation precision of the boundary layers and the shearing layers.

And (3) performing aerodynamic force calculation on different position configurations of the flap by using a pressure correction algorithm, and utilizing a pressure base solver in FLUENT. The pressure-based solver takes momentum and pressure as basic variables, is suitable for most of unidirectional flows, and selects a method of solving gradient based on a Gaussian Green function of nodes to calculate resistance.

The SST two-equation turbulence model is suitable for the problem of wall surface boundary layer flow, and has better effect on the boundary layer fluid flow under the action of inverse pressure gradient.

The physical properties of the flow field are defined by adopting a Satherland model, and the relation between the dynamic viscosity mu and the absolute temperature T of rational gas is explained.As is the Sutherland coefficient and Ts is the Sutherland temperature, and the kinetic viscosity mu can be calculated.

The discrete format adopts a windward format for discrete, and the time integral is solved by a Runge-Kutta method expression. The coupling of pressure and speed is carried out by adopting a SIMPLEC method, and a second-order windward format is adopted in a differential format.

Model and numerical methods: based on finite volume discrete equations on the structural grid,

wherein the flow velocityГ^ΦIs the diffusion coefficient, S^ΦAs a source term, the discrete form of a discrete equation on any control volume is:whereinIn the case of the interface flux density,is the infinitesimal area, Δ V is the infinitesimal volume, nf is the infinitesimal surface number, phi in the convection term_fBy adopting a second-order windward format, a pressure correction quantity, a speed and turbulent flow viscosity coefficient equation is finally formed as follows:for lift calculation.

And (4) calculating to obtain a lift coefficient curve chart, and referring to fig. 5, the lift coefficients corresponding to the NACA 650I position configuration, the NACA 650 II position configuration, the NACA 650 III position configuration and the NACA 650 IV position configuration are stable and show an increasing trend as a whole.

Example 3

Selecting a main wing NACA65-205 airfoil profile, and configuring the multi-level flap of the invention aiming at the NACA65-205 airfoil profile, wherein the main wing NACA65-205 airfoil profile comprises the following components: NACA 651I positional configuration, NACA 651 II positional configuration, NACA 651 III positional configuration, NACA 651 IV positional configuration. The attack angle range is 0-12 degrees, the interval is 2 degrees, and the aerodynamic characteristics of 7 points are totally obtained.

The numerical simulation adopts a structural grid, the C-H type grid is taken as a leading factor, the far-field boundary of a calculation domain is 120 times of chord length, and the first row of grids on the wall surface is 1.0 multiplied by 10^-7And the grids are encrypted at the wing seams, boundary layers, trail regions and the like to capture the slight change of the flow field and ensure the numerical simulation precision of the boundary layers and the shearing layers.

And (3) performing aerodynamic force calculation on different position configurations of the flap by using a pressure correction algorithm, and utilizing a pressure base solver in FLUENT. The pressure-based solver takes momentum and pressure as basic variables, is suitable for most of unidirectional flows, and selects a method of solving gradient based on a Gaussian Green function of nodes to calculate resistance.

The SST two-equation turbulence model is suitable for the problem of wall surface boundary layer flow, and has better effect on the boundary layer fluid flow under the action of inverse pressure gradient.

The flow field physical property is defined by adopting a Satherland model, and the relation between the dynamic viscosity and the absolute temperature of rational gas is explained.As is the Sutherland coefficient and Ts is the Sutherland temperature, and the dynamic viscosity can be calculated.

The discrete format adopts a windward format for discrete, and the time integral is solved by a Runge-Kutta method expression. The coupling of pressure and speed is carried out by adopting a SIMPLEC method, and a second-order windward format is adopted in a differential format.

Model and numerical methods: based on finite volume discrete equations on the structural grid,

wherein the flow velocityГ^ΦIs the diffusion coefficient, S^ΦAs a source term, the discrete form of a discrete equation on any control volume is:whereinIn the case of the interface flux density,is the infinitesimal area, Δ V is the infinitesimal volume, nf is the infinitesimal surface number, phi in the convection term_fBy adopting a second-order windward format, a pressure correction quantity, a speed and turbulent flow viscosity coefficient equation is finally formed as follows:for lift calculation.

And (4) calculating to obtain a lift coefficient curve chart, and referring to fig. 6, the lift coefficients corresponding to the NACA 651I position configuration, the NACA 651 II position configuration, the NACA 651 III position configuration and the NACA 651 IV position configuration are stable and show an increasing trend as a whole.

Example 4

Selecting a main wing NACA65-205 airfoil profile, and configuring the multi-level flap of the invention aiming at the NACA65-205 airfoil profile, wherein the main wing NACA65-205 airfoil profile comprises the following components: NACA 652I position configuration, NACA 652 II position configuration, NACA 652 III position configuration, and NACA 652 IV position configuration. The attack angle range is 0-12 degrees, the interval of 2 degrees, and the aerodynamic characteristics of 7 points are researched.

The numerical simulation adopts a structural grid, the C-H type grid is taken as a leading factor, the far-field boundary of a calculation domain is 120 times of chord length, and the first row of grids on the wall surface is 1.0 multiplied by 10^-7And the grids are encrypted at the wing seams, boundary layers, trail regions and the like to capture the slight change of the flow field and ensure the numerical simulation precision of the boundary layers and the shearing layers.

And (3) performing aerodynamic force calculation on different position configurations of the flap by using a pressure correction algorithm, and utilizing a pressure base solver in FLUENT. The pressure-based solver takes momentum and pressure as basic variables, is suitable for most of unidirectional flows, and selects a method of solving gradient based on a Gaussian Green function of nodes to calculate resistance.

The SST two-equation turbulence model is suitable for the problem of wall surface boundary layer flow, and has better effect on the boundary layer fluid flow under the action of inverse pressure gradient.

The flow field physical property is defined by adopting a Satherland model, and the relation between the dynamic viscosity and the absolute temperature of rational gas is explained.As is the Sutherland coefficient and Ts is the Sutherland temperature, and the dynamic viscosity can be calculated.

The discrete format adopts a windward format for discrete, and the time integral is solved by a Runge-Kutta method expression. The coupling of pressure and speed is carried out by adopting a SIMPLEC method, and a second-order windward format is adopted in a differential format.

Model and numerical methods: based on finite volume discrete equations on the structural grid,

wherein the flow velocityΓ^ΦIs the diffusion coefficient, S^ΦAs a source term, the discrete form of a discrete equation on any control volume is:whereinIn the case of the interface flux density,is the infinitesimal area, Δ V is the infinitesimal volume, nf is the infinitesimal surface number, phi in the convection term_fBy adopting a second-order windward format, a pressure correction quantity, a speed and turbulent flow viscosity coefficient equation is finally formed as follows:for lift calculation.

And (4) calculating to obtain a lift coefficient curve chart, and referring to fig. 7, the lift coefficients corresponding to the NACA 652I position configuration, the NACA 652 II position configuration, the NACA 652 III position configuration and the NACA 652 IV position configuration are stable and show an increasing trend as a whole.

The comparison of the lift coefficient graphs of the embodiments 2, 3 and 4 shows that by changing the clamping position configuration and the deflection angle configuration of the multi-level flap, the lift coefficient curve shows that as the clamping position of the multi-level flap is changed from the '0 position' to the '1 position' and then to the '2 position', the lift coefficient is stably increased, and as the deflection angle of the flap is increased, the lift coefficient is further stably increased, so that the arrangement of the multi-level flap provides more effective landing configurations for the large-sized freight unmanned aerial vehicle, the difference between the front and the rear of the load of the large-sized freight unmanned aerial vehicle is large, and the safe landing is realized with important reference and practical significance.

Example 5

In order to further verify the reliability of the pressure correction algorithm result, the experimental values are compared through a wind tunnel test, and two configurations of the 2 position of the multi-level flap are carried out: 2 II and 2 III, wind tunnel tests are carried out, lift coefficient curves are obtained and compared with the calculation results of the method, the lift coefficient curves are compared with the results shown in the figures 8 and 9, and the comparison shows that the pressure correction algorithm results and the experiment results are good in conformity, so that the pressure correction algorithm adopted by the method can well carry out flap aerodynamic evaluation calculation, and an effective and accurate calculation method is provided for the landing configuration design of the large-sized freight unmanned aerial vehicle.

The above embodiments further illustrate and explain the landing configuration design of a large-scale freight unmanned aerial vehicle disclosed in the present invention, and the description of the above embodiments is only used to help understand the method and the core idea of the present application, and for those skilled in the art, according to the idea of the present application, there may be changes in the specific implementation and application scope, and the content of the present description should not be construed as a limitation to the present application.