A design method for a high-speed and efficient UAV based on a new configuration

Abstract

The present invention discloses a design method for a high-speed and high-efficiency unmanned aerial vehicle (UAV) based on a new configuration. In this method, a main propeller and a motor providing lift are first designed based on the requirement of optimal efficiency. Then, a tail pusher propeller and a motor providing forward flight power are designed based on the requirement of optimal efficiency. The wake condition of the main propeller is obtained, and the overlapping interference area between the wake condition and the tail pusher propeller is comprehensively considered to reduce mutual interference. At the same time, other requirements for the setting position of the tail pusher propeller are met, and then the tail pusher propeller installation position with the best efficiency is obtained, thereby completing the design process of the unmanned tail pusher propeller and obtaining a tail pusher UAV with better efficiency.

Description

Technical Field

[0001] The present invention relates to a design method for an unmanned aerial vehicle (UAV), and in particular to a design method for a high-speed and high-efficiency UAV based on a new configuration. Background Art

[0002] Multi-rotor drones (UAVs) are now widely used in both military and civilian applications due to their maneuverability and flexibility. However, as they are used in a growing number of scenarios, their flight speed and power have become major limitations that hinder their application.

[0003] In response to the above problems, some people have proposed a tail-push propeller structure, that is, the main propeller is only used to provide lift. During the flight of the UAV, it no longer tilts forward, and the forward motion is provided by the tail-push propeller. However, this is only a concept. How to set up a specific tail-push UAV structure to maximize the performance of the UAV with the best efficiency has become a restrictive factor in the development of tail-push UAVs.

[0004] The present invention fully studies the working mechanism of a tail-push UAV and proposes a design method for a high-speed and high-efficiency UAV based on a new configuration that can achieve optimal efficiency in order to obtain a tail-push UAV with optimal efficiency. Summary of the Invention

[0005] In order to overcome the above problems, the inventors have conducted intensive research and designed a design method for a high-speed and high-efficiency UAV based on a new configuration. In this method, the main propeller and its motor that provide lift are first designed based on the requirement of optimal efficiency, and then the tail pusher propeller and motor that provide forward flight power are designed based on the requirement of optimal efficiency. The wake condition of the main propeller is obtained, and the overlapping interference area between the wake condition and the tail pusher propeller is comprehensively considered to reduce mutual interference. At the same time, other tail pusher propeller setting position requirements are met, and then the most efficient tail pusher propeller installation position is obtained, thereby completing the design process of the tail pusher propeller unmanned aerial vehicle, obtaining a more efficient tail pusher UAV, and completing the present invention.

[0006] Specifically, the purpose of the present invention is to provide a design method for a high-speed and high-efficiency UAV based on a new configuration, the method comprising:

[0007] S1: Design the main propeller model and main propeller motor;

[0008] S2: Design the model of the tail thruster propeller and the tail thruster propeller motor;

[0009] S3: Determine the tail thruster propeller position.

[0010] Wherein, the S1 specifically includes the following steps:

[0011] Step 1: Based on the design conditions, select multiple main propeller models that can meet the takeoff quality requirements, and each main propeller model corresponds to a different radius length;

[0012] Step 2: Conduct wind tunnel tests on the selected main propellers in sequence, measuring the aerodynamic force and input voltage and current of each main propeller at different incoming flow velocities and rotational speeds. This will then determine the aerodynamic efficiency of each main propeller at takeoff weight. The propellers are then sorted by size to select the main propeller model with the highest aerodynamic efficiency.

[0013] Step 3: retrieve the main propeller information selected in step 2, and preliminarily obtain the KV value of the motor required for the main propeller based on its speed at takeoff mass.

[0014] According to the maximum power required by the main propeller, the maximum power of the required motor is preliminarily obtained;

[0015] Step 4: Select several motors that meet the KV value and maximum power requirements, and obtain the matching degree between the main propeller and the motor based on the motor characteristic curve;

[0016] Step 5: Sort the selected motors by conversion efficiency, and select the motor with the highest conversion efficiency as the main propeller motor;

[0017] Wherein, the S2 specifically includes the following steps: Step 6, based on the design conditions, selecting multiple tail-thrust propeller models that can meet the resistance requirements of the UAV, and each tail-thrust propeller model corresponds to a different radius length;

[0018] Step 7: Conduct wind tunnel tests on the selected multiple tail-thrust propellers in sequence, measuring the aerodynamic force and input voltage and current of each tail-thrust propeller at different incoming flow velocities and rotational speeds, thereby obtaining the aerodynamic efficiency of each tail-thrust propeller at takeoff weight. The propellers are then sorted by size to select the tail-thrust propeller model with the highest aerodynamic efficiency.

[0019] Step 8: Preliminarily obtain the KV value of the motor required for the tail thruster propeller selected in step 7 based on its speed under typical operating conditions, and preliminarily obtain the maximum power required for the motor based on the maximum power required for the tail thruster propeller;

[0020] Step 9: Select several motors that meet the KV value and maximum power requirements, and obtain the matching degree between the tail thrust propeller and the motor according to the motor characteristic curve;

[0021] Step 10: sort the selected motors according to conversion efficiency, and select the motor with the highest conversion efficiency as the tail propeller motor;

[0022] Among them, the S3 specifically includes the following steps: Step 11, performing CFD numerical simulation tests on the aerodynamic layout of the main propeller and the fuselage, analyzing and obtaining the main propeller wake conditions, and determining the tail thrust propeller position according to the main propeller wake conditions.

[0023] In step 1, the relationship between the main propeller radius and the design conditions is obtained by the following formula (1):

[0024]

[0025] Wherein, GTOW represents the take-off mass of the UAV, n represents the number of main propellers on the UAV, and T p Represents the thrust of a single main propeller, R p represents the main propeller radius, and ξ1 represents the main propeller disk load factor.

[0026] Wherein, in step 3, the KV value is obtained by the following formula (2);

[0027]

[0028] Among them, ω w Indicates the rotational speed of the main propeller at takeoff mass; U w Indicates the motor operating voltage;

[0029] In step 3, the maximum power P of the motor max Obtained by the following formula (3);

[0030] P max =δP w (three)

[0031] Among them, δ represents the control margin; P w Indicates the power required by the main propeller at takeoff mass.

[0032] Wherein, in step 4, the motor characteristic curve is obtained by the following formula (4):

[0033]

[0034] Among them, U d Indicates the motor input voltage, r a represents the motor resistance, I represents the motor input current, k e represents the line back electromotive force coefficient, ω represents the motor rotor speed, K T Indicates the motor torque coefficient, T L Indicates load torque, B V represents the viscous friction coefficient;

[0035] Preferably, the matching degree between the main propeller and the motor is obtained by the following formula (5):

[0036]

[0037] Among them, T L The value of is equal to the torque of the main propeller, and the value of ω is equal to the speed of the main propeller.

[0038] In step 6, the relationship between the tail thruster propeller radius and the design conditions is obtained by the following formula (6):

[0039]

[0040] Among them, the D p represents the aerodynamic drag generated by a main propeller, n represents the number of main propellers on the drone, D f Indicates the resistance generated by the fuselage, T t Represents the thrust of a single tail propeller, R t represents the radius of the tail pusher propeller, and ξ2 represents the load factor of the tail pusher propeller disc.

[0041] Wherein, in step 11, the process of obtaining the main propeller wake condition includes the following sub-steps:

[0042] Sub-step 1: construct a 3D model of the main propeller and fuselage and import it into Ansys commercial software;

[0043] Sub-step 2, meshing the three-dimensional model using the mesh sub-software in Ansys commercial software;

[0044] Step 3: Import the meshed 3D model into the Fluent sub-software of Ansys commercial software to perform time-varying CFD numerical simulation on the 3D model to obtain the wake position and size.

[0045] Wherein, in step 11, the setting of the tail thruster propeller position satisfies the following conditions:

[0046] Condition 1: The tail propeller sweep area does not interfere with the ground or other UAV structures;

[0047] Condition 2: tail thrust propeller thrust loss η < 5%;

[0048] Condition 3: The maximum outer envelope of the drone is as small as possible;

[0049] Condition 4: The center of the tail propeller is above the center of the main propeller.

[0050] Preferably, in condition 2, the tail thrust propeller thrust loss η is obtained by the following formula (VII):

[0051]

[0052] Among them, T0 is the thrust generated when the tail thruster is measured alone, and T1 is the thrust generated when the tail thruster is installed on the fuselage with the main propeller at the same speed.

[0053] The beneficial effects of the present invention include:

[0054] (1) According to the design method of a high-speed and high-efficiency UAV based on a new configuration provided by the present invention, the method can quickly provide the main propeller and tail pusher propeller with the optimal efficiency combination according to specific design requirements, so that the designed tail pusher UAV has the best efficiency and meets the design requirements;

[0055] (2) According to the design method of the high-speed and high-efficiency UAV based on the new configuration provided by the present invention, the main propeller wake condition is obtained through CFD numerical simulation, and then the appropriate tail propeller position is set, thereby simplifying the structure and improving efficiency while meeting the design requirements of the UAV. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 A schematic diagram of a three-dimensional model of a main propeller in an embodiment of the present application is shown;

[0057] Figure 2 A schematic diagram of the grid shape of the drone body in an embodiment of the present application is shown;

[0058] Figure 3 A schematic diagram showing the size of the wake of the main propeller of the drone in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0059] The present invention will be described in further detail below with reference to the accompanying drawings and examples, through which the features and advantages of the present invention will become more clearly understood.

[0060] The word "exemplary" is used exclusively herein to mean "serving as an example, example, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

[0061] According to the present invention, a design method for a high-speed and high-efficiency UAV based on a new configuration is provided, the method comprising the following steps:

[0062] Step 1: Based on the design conditions, select multiple main propeller models that can meet the takeoff quality requirements, and each main propeller model corresponds to a different radius length; preferably, the UAV has multiple main propellers, generally four, and the main propellers are symmetrically arranged about the center of gravity of the UAV fuselage, and the four main propellers are of the same model;

[0063] Preferably, in step 1, the relationship between the main propeller radius length and the design conditions is obtained by the following formula (1):

[0064]

[0065] Wherein, GTOW represents the take-off mass of the UAV, n represents the number of main propellers on the UAV, and T p Represents the thrust of a single main propeller, R p represents the main propeller radius, ξ1 represents the main propeller disk load factor, which is obtained through wind tunnel tests.

[0066] In this application, the design conditions include the take-off mass of the UAV and the number of main propellers.

[0067] Preferably, in order to ensure sufficient design domain, the actual main propeller radius is generally taken as The range is: Preferably, in step 1, at least five main propeller models that can meet the takeoff quality requirements are selected, and the sizes of these main propeller models are all within 1.1R p to 0.9R p between;

[0068] For example, models: NS3010, NS2806, MF3218, G2809, G3010 (corresponding models on the T-motor official website). Currently, propellers of various models and sizes are available on the market. In this application, a propeller that meets the requirements is selected from the various models and sizes available.

[0069] Step 2: Conduct wind tunnel tests on the selected main propellers in sequence, measuring the aerodynamic force and input voltage and current of each main propeller at different incoming flow velocities and rotational speeds. This will then determine the aerodynamic efficiency of each main propeller at takeoff weight. The propellers are then sorted by size to select the main propeller model with the highest aerodynamic efficiency.

[0070] Step 3: retrieve the main propeller information selected in step 2, and preliminarily obtain the KV value of the motor required for the main propeller based on its speed at takeoff mass.

[0071] According to the maximum power required by the main propeller, the maximum power of the required motor is preliminarily obtained;

[0072] In step 3, the KV value is obtained by the following formula (2):

[0073]

[0074] Among them, ω w represents the rotational speed of the main propeller at takeoff mass, which is obtained from the wind tunnel test in step 2; Uw represents the motor operating voltage, which is obtained from the wind tunnel test in step 2;

[0075] In step 3, the maximum power P of the main propeller motor max Obtained by the following formula (3);

[0076] P max =δP w (three)

[0077] Among them, δ represents the main propeller control margin, which is 0.4-0.6; P w It represents the power required by the main propeller at takeoff mass, and the value is obtained through wind tunnel testing.

[0078] Step 4: Select several motors that meet the KV value and maximum power requirements, and obtain the matching degree between the main propeller and the motor based on the motor characteristic curve;

[0079] Preferably, select at least 5 motors that meet the KV value and maximum power requirements;

[0080] The matching degree described in this application refers to: the conversion efficiency of the motor when the propeller and the motor are operating in the hovering mode; the higher the motor conversion efficiency, the better the matching degree.

[0081] In step 4, the motor characteristic curve is obtained by the following formula (4):

[0082]

[0083] Among them, U d Indicates the motor input voltage, which is the rated value / fixed value of the motor, r a Indicates the motor resistance, which is the rated value / fixed value of the motor, I indicates the motor input current, which is the rated value / fixed value of the motor, k e represents the line back EMF coefficient, which is obtained by fitting the data obtained from the wind tunnel test and the rated value of the motor. ω represents the motor rotor speed, which is obtained through the wind tunnel test. K T Represents the motor torque coefficient, which is obtained by fitting the data obtained from the wind tunnel test and the rated value of the motor. L Denotes the load torque, obtained through wind tunnel testing, B V Represents the viscous friction coefficient, which is obtained by fitting the data obtained from the wind tunnel test and the rated value of the motor;

[0084] Preferably, the matching degree between the main propeller and the motor, also referred to as the motor conversion efficiency, is specifically obtained by the following formula (5):

[0085]

[0086] Among them, TL The value of is equal to the torque of the main propeller, and the value of the torque of the main propeller is obtained through a wind tunnel test. The value of ω is equal to the rotational speed of the main propeller, and the value of the rotational speed of the main propeller is obtained through a wind tunnel test.

[0087] Step 5: Sort the selected motors by conversion efficiency, and select the motor with the highest conversion efficiency as the main propeller motor;

[0088] Step 6: Based on the design conditions, select multiple tail-thrust propeller models that can meet the UAV's drag requirements, with each tail-thrust propeller model corresponding to a different radius length. The design conditions here include the drag value generated by the UAV fuselage, and accordingly, the tail-thrust propeller can provide thrust greater than the drag value.

[0089] The tail thrust propeller described in this application refers to a propeller arranged at the tail of the drone with the blade surface perpendicular to the horizontal direction, which can generate horizontal thrust through rotation.

[0090] Preferably, in step 6, the relationship between the tail thruster propeller radius length and the design conditions is obtained by the following formula (VI):

[0091]

[0092] Among them, the D p represents the aerodynamic drag generated by a main propeller, which is obtained through wind tunnel tests, n represents the number of main propellers on the UAV, D f Indicates the resistance generated by the fuselage, T t Represents the thrust of a single tail propeller, R t represents the radius of the tail thruster propeller, and ξ2 represents the load factor of the tail thruster propeller disc, which is obtained through wind tunnel tests.

[0093] Preferably, in order to ensure sufficient design domain, the actual tail thrust propeller radius is generally taken as The range is: Preferably, in step 6, at least five tail-thrust propeller models that can meet the takeoff quality requirements are selected, and the sizes of these tail-thrust propellers are all within 1.1R. t to 0.9R t between.

[0094] Step 7: Conduct wind tunnel tests on the selected multiple tail-thrust propellers in sequence, measuring the aerodynamic force and input voltage and current of each tail-thrust propeller at different incoming flow velocities and rotational speeds, thereby obtaining the aerodynamic efficiency of each tail-thrust propeller at takeoff weight. The propellers are then sorted by size to select the tail-thrust propeller model with the highest aerodynamic efficiency.

[0095] Step 8: retrieve the tail thrust propeller information selected in step 7, and preliminarily obtain the KV value of the motor required for the tail thrust propeller based on its speed under typical working conditions.

[0096] According to the maximum power required by the tail thruster propeller, the maximum power of the required motor is preliminarily obtained;

[0097] The method of obtaining the KV value is similar to that of the main propeller motor.

[0098]

[0099] Among them, ω′ w represents the speed of the tail thrust propeller under typical working conditions, which is obtained from the wind tunnel test in step 7; U w represents the motor operating voltage, which is obtained from the wind tunnel test in step 7;

[0100] The typical operating condition described in this application refers to the forward flight mode with a non-zero speed and a pitch angle of 0;

[0101] Among them, the maximum power of the tail propeller motor P m ' ax The method of obtaining the maximum power P of the tail propeller motor of the main propeller motor is the same as max The method of obtaining is similar.

[0102] P′ max =δ′P′ w

[0103] Among them, δ′ represents the tail thrust propeller control margin, which is 0.4-0.6; P′ w It represents the power required by the tail pusher propeller under typical operating conditions. This value is obtained through wind tunnel tests.

[0104] Step 9: Select several motors that meet the KV value and maximum power requirements, and obtain the matching degree between the tail thrust propeller and the motor based on the motor characteristic curve; preferably, select at least 5 motors that meet the KV value and maximum power requirements;

[0105] In this application, the selection method of the motor for the tail thrust propeller is similar to that of the motor for the main propeller, and the motor characteristic curve is shown in Formula (IV); the matching degree between the tail thrust propeller and the motor is also called the motor conversion efficiency.

[0106] Step 10: sort the selected motors according to conversion efficiency, and select the motor with the highest conversion efficiency as the tail propeller motor;

[0107] Step 11: Perform CFD numerical simulation on the aerodynamic layout of the main propeller and fuselage to analyze and obtain the main propeller wake, and determine the position of the tail thrust propeller based on the main propeller wake. The wake includes the forward tip vortex, the backward tip vortex, the root vortex, and the tip wake vortex.

[0108] Preferably, in step 11, the process of obtaining the main propeller wake condition includes the following sub-steps:

[0109] Sub-step 1: construct a 3D model of the main propeller and fuselage and import it into Ansys commercial software;

[0110] Sub-step 2, meshing the three-dimensional model using the mesh sub-software in Ansys commercial software;

[0111] Step 3: Import the meshed 3D model into the Fluent sub-software of Ansys commercial software to perform time-varying CFD numerical simulation on the 3D model to obtain the wake position and size.

[0112] The ANSYS commercial software is a large-scale general-purpose finite element analysis (FEA) software developed by ANSYS Corporation of the United States.

[0113] Preferably, in step 11, the setting of the tail thruster propeller position satisfies the following conditions:

[0114] Condition 1: The tail propeller sweep area does not interfere with the ground or other UAV structures; this condition is a necessary condition that must be met;

[0115] Condition 2: tail thrust propeller thrust loss η < 5%. This condition is a necessary condition that must be met to ensure acceptable efficiency of the UAV.

[0116] Condition 3: The drone's maximum outer envelope must be as small as possible. This outer envelope refers to the smallest cylinder that can completely enclose the drone. This condition is an optimization condition that must be met as much as possible to reduce unnecessary drone size, improve efficiency, and facilitate portability and storage.

[0117] Condition 4: The center of the tail propeller is located above the center of the main propeller. This condition is an optimization condition that should be met as much as possible to improve the efficiency of the UAV.

[0118] Among them, in condition 4, when there are multiple main propellers, the main propeller with the highest center position among the multiple main propellers is compared with the tail thruster propeller to ensure that the center height of the tail thruster propeller is higher than the center height of the main propeller.

[0119] Preferably, in condition 2, the tail thrust propeller thrust loss η is obtained by the following formula (VII):

[0120]

[0121] Among them, T0 is the thrust generated when the tail thruster is measured alone, and T1 is the thrust generated when the tail thruster is installed on the fuselage with the main propeller at the same speed.

[0122] Example

[0123] Design a high-speed and efficient UAV with a tail-thrust propeller. The design conditions are as follows:

[0124] The drone’s takeoff mass is 20kg;

[0125] The number of main propellers is 4, and the number of tail propellers is 1;

[0126] The maximum size of the fuselage, that is, the smallest cylindrical body that can completely enclose the drone, is 2000mm in diameter and 800mm in height;

[0127] The corresponding resistance generated by the fuselage is 10N;

[0128] Flight radius 54km;

[0129] Flight time: 45 minutes;

[0130] Flight speed 20m / s;

[0131] Maximum flight speed 30m / s;

[0132] The design process is as follows:

[0133] Step 1: Based on the design conditions, select five main propeller models that can meet the takeoff quality requirements, and each main propeller model corresponds to a different radius length;

[0134] The relationship between the main propeller radius and design conditions is obtained through the following formula (1):

[0135]

[0136] Among them, the load factor of the main propeller disc is 4.82;

[0137] The specific models of the five main propellers selected are: NS3010, NS2806, MF3218, G2809, G3010;

[0138] The corresponding radius lengths are 15in, 14in, 16in, 14in, 15in;

[0139] Step 2: Conduct wind tunnel tests on the selected main propellers in sequence, measuring the aerodynamic force and input voltage and current of each main propeller at different incoming flow velocities and rotational speeds. This will then determine the aerodynamic efficiency of each main propeller at takeoff weight. The propellers are then sorted by size to select the main propeller model with the highest aerodynamic efficiency.

[0140] The specific relationship between the incoming flow velocity, rotation speed, aerodynamic force and input voltage and current is shown in the following table:

[0141]

[0142] The main propeller model with the highest efficiency was NS3010;

[0143] Step 3: retrieve the main propeller information selected in step 2, and preliminarily obtain the KV value of the motor required for the main propeller based on its speed at takeoff mass.

[0144] According to the maximum power required by the main propeller, the maximum power of the required motor is preliminarily obtained;

[0145] Wherein, the KV value is obtained by the following formula (2):

[0146]

[0147] Among them, ω w The value is 1551.28rpm; U w The value is 47.80V; the final KV is 32.47,

[0148] The maximum power P of the main propeller motor max Obtained by the following formula (3);

[0149] P max =δP w (three)

[0150] Among them, δ is 5, P w The value is 207.1652; the final P max is 1035.826;

[0151] Step 4: Select five motors that meet the KV value and maximum power requirements. The specific models and related parameters of the five motors are Antigravity MN1005, MN1010, MN8007, U12II, and P90.

[0152] Obtain the matching degree between the main propeller and the motor according to the motor characteristic curve;

[0153] The motor characteristic curve is obtained by the following formula (4):

[0154]

[0155] The matching degree between the main propeller and the motor, also known as the motor conversion efficiency, is obtained by the following formula (5):

[0156]

[0157] Step 5: Sort the selected motors by conversion efficiency and select the motor with the highest conversion efficiency as the main propeller motor, specifically the Antigravity MN1005 motor;

[0158] Step 6: Based on the design conditions, select five tail-thrust propeller models that can meet the UAV's drag requirements, and each tail-thrust propeller model corresponds to a different radius length;

[0159] The relationship between the tail thruster propeller radius and design conditions is obtained through the following formula (6):

[0160]

[0161] Among them, the tail thrust propeller disc load factor is 13.16;

[0162] The specific models of the five tail thrust propellers selected are: 1714, 1814, 1913, 2014, and 2113;

[0163] The corresponding radius lengths are 8.5in, 9in, 9.5in, 10in, 10.5in;

[0164] Step 7: Conduct wind tunnel tests on the selected propellers in turn, measuring the aerodynamic force and input voltage and current of each propeller at different incoming flow velocities and rotational speeds. This will then determine the aerodynamic efficiency of each propeller at takeoff weight, sort the propellers by size, and select the main propeller model with the highest aerodynamic efficiency.

[0165] The specific relationship between the incoming flow velocity, rotation speed, aerodynamic force and input voltage and current is shown in the following table:

[0166]

[0167] The tail-push propeller model with the highest efficiency was 1913;

[0168] Step 8: retrieve the tail thrust propeller information selected in step 7, and based on its rotational speed at takeoff mass, preliminarily obtain the KV value of the motor required for the tail thrust propeller.

[0169] According to the maximum power required by the tail thruster propeller, the maximum power of the required motor is preliminarily obtained;

[0170]

[0171] Among them, ω′ w The value is 5216.474rpm; U w The value is 55V; the final KV is 94.84;

[0172] P′ max =δ′P′ w

[0173] Among them, δ′ is 5, P′ w The value is 1005.455; the final P′ max is 5027.275;

[0174] Step 9: Select 5 motors that meet the KV value and maximum power requirements. The specific models and related parameters of the 5 motors are AT4130, AT5220, AT5230, AT5330, and AT7215.

[0175] Obtain the matching degree between the main propeller and the motor according to the motor characteristic curve;

[0176] Step 10: sort the selected motors by conversion efficiency, and select the motor with the highest conversion efficiency as the main propeller motor, specifically the AT5330 motor;

[0177] Step 11: Perform CFD numerical simulation tests on the aerodynamic layout of the main propeller and fuselage, analyze and obtain the main propeller wake conditions, and determine the tail thrust propeller position based on the main propeller wake conditions.

[0178] Wherein, in step 11, the process of obtaining the main propeller wake condition includes the following sub-steps:

[0179] Sub-step 1, construct the 3D model of the main propeller and fuselage and import it into Ansys commercial software, such as Figure 1 As shown in;

[0180] Sub-step 2: Use the mesh sub-software in Ansys commercial software to mesh the 3D model. The number and proportion of meshes in the main areas are shown in the following table:

[0181]

[0182]

[0183] The specific grid shape obtained is as follows Figure 2 As shown in Figure 2 In the figure, area 2 belongs to the local enlargement of area 1, area 3 belongs to the local enlargement of area 2, and area 4 belongs to the local enlargement of area 3;

[0184] Step 3: Import the meshed 3D model into the fluent sub-software of Ansys commercial software to perform time-varying CFD numerical simulation on the 3D model. The simulation parameters are set as shown in the table below to obtain the wake position and size. Figure 3 As shown in:

[0185]

[0186] In step 11, the setting of the tail thruster propeller position satisfies the following conditions:

[0187] Condition 1: The tail propeller sweep area does not interfere with the ground or other UAV structures;

[0188] Condition 2: The tail thrust propeller thrust loss is less than 5%;

[0189] Condition 3: The maximum outer envelope of the drone is as small as possible;

[0190] Condition 4: The center of the tail propeller is above the center of the main propeller.

[0191] Based on the conditions in step 11, design the distance x between the center of the tail thrust propeller and the centers of the two main propellers behind it. rt =600mm, top and bottom distance z rt =128mm, with the center located in the longitudinal symmetry plane of the UAV.

[0192] The present invention has been described above with reference to preferred embodiments, but these embodiments are merely exemplary and serve only as illustrations. On this basis, various replacements and improvements can be made to the present invention, all of which fall within the scope of protection of the present invention.

Claims

1. A design method for a high-speed and high-efficiency UAV based on a new configuration, characterized in that: The method includes: S1: Design and obtain the main propeller model and main propeller motor; S2: Design the model of the tail thruster propeller and the tail thruster propeller motor; S3: Determine the position of the tail thrust propeller; The S1 specifically includes the following steps: Step 1: Based on the design conditions, select multiple main propeller models that can meet the takeoff quality requirements, and each main propeller model corresponds to a different radius length; Step 2: Conduct wind tunnel tests on the selected main propellers in sequence, measuring the aerodynamic force and input voltage and current of each main propeller at different incoming flow velocities and rotational speeds. This will then determine the aerodynamic efficiency of each main propeller at takeoff weight. The propellers are then sorted by size to select the main propeller model with the highest aerodynamic efficiency. Step 3: retrieve the main propeller information selected in step 2, and preliminarily obtain the KV value of the motor required for the main propeller based on its speed at takeoff mass. According to the maximum power required by the main propeller, the maximum power of the required motor is preliminarily obtained; Step 4: Select several motors that meet the KV value and maximum power requirements, and obtain the matching degree between the main propeller and the motor based on the motor characteristic curve; Step 5: Sort the selected motors by conversion efficiency, and select the motor with the highest conversion efficiency as the main propeller motor; In step 1, the relationship between the main propeller radius and the design conditions is obtained by the following formula (1): Wherein, GTOW represents the take-off mass of the UAV, n represents the number of main propellers on the UAV, and T p Indicates the thrust of a single main propeller, R p represents the main propeller radius, and ξ1 represents the main propeller disk load factor.

2. The design method of a high-speed and high-efficiency UAV based on a new configuration according to claim 1 is characterized in that: The S2 specifically includes the following steps: Step 6: Based on the design conditions, select multiple tail-thrust propeller models that can meet the UAV's drag requirements, and each tail-thrust propeller model corresponds to a different radius length; Step 7: Conduct wind tunnel tests on the selected multiple tail-thrust propellers in sequence, measuring the aerodynamic force and input voltage and current of each tail-thrust propeller at different incoming flow velocities and rotational speeds, thereby obtaining the aerodynamic efficiency of each tail-thrust propeller at takeoff weight. The propellers are then sorted by size to select the tail-thrust propeller model with the highest aerodynamic efficiency. Step 8: Preliminarily obtain the KV value of the motor required for the tail thruster propeller selected in step 7 based on its speed under typical operating conditions, and preliminarily obtain the maximum power required for the motor based on the maximum power required for the tail thruster propeller; Step 9: Select several motors that meet the KV value and maximum power requirements, and obtain the matching degree between the tail thrust propeller and the motor according to the motor characteristic curve; Step 10: sort the selected motors according to conversion efficiency, and select the motor with the highest conversion efficiency as the tail propeller motor.

3. The design method of a high-speed and high-efficiency UAV based on a new configuration according to claim 1 is characterized in that: The S3 specifically includes the following steps: Step 11: Perform CFD numerical simulation tests on the aerodynamic layout of the main propeller and fuselage, analyze and obtain the main propeller wake conditions, and determine the tail thrust propeller position based on the main propeller wake conditions.

4. The design method of a high-speed and high-efficiency UAV based on a new configuration according to claim 1 is characterized in that: In step 3, the KV value is obtained by the following formula (2): Among them, ω w Indicates the rotational speed of the main propeller at takeoff mass; U w Indicates the motor operating voltage; In step 3, the maximum power P of the motor max Obtained by the following formula (3); P max =δP w (three) Among them, δ represents the control margin; P w Indicates the power required by the main propeller at takeoff mass.

5. The design method of a high-speed and high-efficiency UAV based on a new configuration according to claim 1 is characterized in that: In step 4, the motor characteristic curve is obtained by the following formula (4): Among them, U d Indicates the motor input voltage, r a represents the motor resistance, I represents the motor input current, k e represents the line back electromotive force coefficient, ω represents the motor rotor speed, K T Indicates the motor torque coefficient, T L Indicates load torque, B V represents the viscous friction coefficient; The matching degree between the main propeller and the motor is obtained by the following formula (5): Among them, T L The value of is equal to the torque of the main propeller, and the value of ω is equal to the speed of the main propeller.

6. The design method of a high-speed and high-efficiency UAV based on a new configuration according to claim 2 is characterized in that: In step 6, the relationship between the tail thruster propeller radius and the design conditions is obtained by the following formula (6): Among them, the D p represents the aerodynamic drag generated by a main propeller, n represents the number of main propellers on the drone, D f Indicates the resistance generated by the fuselage, T t Represents the thrust of a single tail propeller, R t represents the radius of the tail-thrust propeller, and ξ2 represents the load factor of the tail-thrust propeller disc.

7. The design method of a high-speed and high-efficiency UAV based on a new configuration according to claim 3 is characterized in that: In step 11, the process of obtaining the main propeller wake condition includes the following sub-steps: Sub-step 1: construct a 3D model of the main propeller and fuselage and import it into Ansys commercial software; Sub-step 2, meshing the three-dimensional model using the mesh sub-software in Ansys commercial software; Step 3: Import the meshed 3D model into the Fluent sub-software of Ansys commercial software to perform time-varying CFD numerical simulation on the 3D model to obtain the wake position and size.

8. The design method of a high-speed and high-efficiency UAV based on a new configuration according to claim 3 is characterized in that: In step 11, the setting of the tail thruster propeller position satisfies the following conditions: Condition 1: The tail propeller sweep area does not interfere with the ground or other UAV structures; Condition 2: tail thrust propeller thrust loss η < 5%; Condition 3: The maximum outer envelope of the drone is as small as possible; Condition 4: the center of the tail propeller is above the center of the main propeller; In condition 2, the tail thrust propeller thrust loss η is obtained by the following formula (VII): Among them, T0 is the thrust generated when the tail thruster is measured alone, and T1 is the thrust generated when the tail thruster is installed on the fuselage with the main propeller at the same speed.

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