Profile-operation-power system joint optimization design method for electric vertical take-off and landing aircraft

Abstract

The invention provides a section-operation-power system joint optimization design method for an electric vertical take-off and landing aircraft. The method comprises the following steps: defining a power system design variable, a section design variable and an operation optimization variable of the electric vertical take-off and landing aircraft; a power system quality model, an aircraft profile demand analysis model, a variable pitch propeller operation performance model and a motor operation performance model are established; power system design and operation control plan making of the electric vertical take-off and landing aircraft are combined, section-operation-power system joint optimization design of the electric vertical take-off and landing aircraft is achieved, and the characteristic of great difference between the wide-speed-range operation characteristic of a variable-pitch propeller and the hovering and cruising flight stage of the vertical take-off and landing aircraft is considered to the maximum extent. And compared with the design of firstly carrying out physical system design and then carrying out operation control design, the optimal design of the overall performance of the aircraft is realized.

Description

Technical Field

[0001] The invention relates to the technical field of aviation aircraft, and in particular to a joint optimization design method for a profile-operation-power system of an electric vertical take-off and landing aircraft. Background Art

[0002] As an emerging aerial transportation tool, electric Vertical Take-Off and Landing Aircraft (eVTOL) is gradually becoming one of the key technologies for the development of low-altitude economy. eVTOL aircraft has the advantages of vertical take-off and landing, high-efficiency cruising, low noise, and low emissions. It is suitable for urban air travel, emergency medical rescue, cargo transportation and other scenarios. Therefore, it has attracted great attention from aviation companies, scientific research institutions and government departments in various countries.

[0003] However, the optimization design of electric vertical take-off and landing aircraft is a multidisciplinary cross-cutting problem, involving multiple aspects such as aerodynamics, operation control, power system and energy management of the aircraft. In particular, the power system of the aircraft, including electric motors, power batteries, thrusters (variable pitch propellers), etc., has a decisive influence on the overall efficiency, range and safety of the aircraft. In vertical take-off and landing aircraft, the propulsion system has two very different working states: vertical take-off and level flight cruise. The formulation of the flight profile greatly affects the formulation of the operation control plan and the overall efficiency of the motor-variable pitch propeller system; in addition, the adjustable pitch and speed of the variable pitch propeller give it a wide operating space, while the design results of the motor restrict the operating range of the propeller.

[0004] Traditional aircraft design methods usually optimize the design in stages and subsystems, ignoring the synergy between different systems and disciplines. This approach often leads to local optimization of overall performance rather than overall optimization. With the gradual development of electric vertical take-off and landing aircraft technology, the optimization of a single system can no longer meet the design requirements under multi-objective and multi-constraint conditions. Therefore, it is hoped that a collaborative optimization design method for the profile-operation-power system will be developed to maximize the consideration of the huge differences between the wide-speed range operation characteristics of the variable-pitch propeller and the hovering and cruising flight stages of the vertical take-off vehicle. Compared with designing the physical system first and then the operation control design, the optimal design of the overall performance of the aircraft is achieved.

[0005] This patent proposes a method for collaborative optimization design of profile-operation-power system of electric vertical take-off and landing aircraft. By building a multidisciplinary coupling optimization model, the profile design, operation performance optimization and power system design of the aircraft are combined. This design method can simultaneously consider power system design, operation control and flight profile formulation, consider multidisciplinary constraints, achieve comprehensive performance optimization of the aircraft, and guide the design and development of eVTOL aircraft. Summary of the invention

[0006] Aiming at the problem that traditional aircraft design methods ignore the synergy between different systems and disciplines, a profile-operation-component joint optimization design method for electric vertical take-off and landing aircraft is proposed, which includes the following steps:

[0007] Step (1): The design variables include the power system design variables d (including the motor design torque Q 电机-设计 、Motor design speedω 电机-设计 , propeller diameter d 螺旋桨 、Number of battery packs 电池组 ) and profile design variables p (including climb speed V 爬升 , Cruising speed V 巡航 , descent speed V 下降 , cruising altitude h 巡航 ); Within the design interval, each design variable randomly generates an initial value to complete the initialization of the design variables, the power system design variables are brought into step (2), and the profile design variables are brought into step (3);

[0008] Step (2): Calculate the power system mass (including the motor mass M) based on the input power system design variable d and the power system mass calculation model. 电机 、Battery quality M 电池 , propeller mass M 螺旋桨 ), and obtain the take-off mass MTOM of the aircraft, which is then brought into step (3); the formula for calculating the mass of the power system is as follows:

[0009] Battery quality model:

[0010] M 电池 =N 电池组 ·M 电池组 (14)

[0011] Where M 电池组 is the weight of a single battery pack;

[0012] Motor mass model:

[0013]

[0014] Where Q 电机-max is the maximum torque of the motor, SQ 电机 is the motor specific torque, P 电机-max is the maximum power of the motor, SP 电机 is the motor specific power;

[0015] Propeller mass model:

[0016]

[0017] Aircraft take-off mass:

[0018] MTOM=M 电池 +M 电机 +M 螺旋桨 +M 空重 (17)

[0019] Where M 空重 is the empty weight of the aircraft (the rest of the weight of the aircraft excluding the power system);

[0020] Step (3): Calculate the vertical take-off and landing aircraft take-off thrust T according to the input profile design variable p, aircraft take-off mass MTOM and aircraft profile requirement analysis model 起飞 , Climbing Required Thrust T 爬升 , cruise required thrust T 巡航 , Decrease demand thrust T 下降 , Landing Required Thrust T 降落 ; According to the number of propellers N 螺旋桨 , calculate the takeoff thrust T required for a single variable pitch propeller 起飞-螺旋桨 , propeller climb required thrust T 爬升-螺旋桨 , propeller cruise required thrust T 巡航-螺旋桨 , propeller descent required thrust T 下降-螺旋桨 , propeller landing thrust required T 降落-螺旋桨 , bring into step (4); the aircraft profile demand analysis model is as follows:

[0021]

[0022] Where g is weight acceleration, S ref is the aircraft reference area, C D爬升 is the drag coefficient of the aircraft during climbing, C D巡航 is the drag coefficient of the aircraft during cruising, C D下降 is the drag coefficient of the aircraft during descent, C L爬升 is the lift coefficient of the aircraft during climbing, C L巡航 is the lift coefficient of the aircraft during cruising, C L下降 is the lift coefficient of the aircraft during descent, γ 爬升 is the aircraft climbing angle during climbing, γ 下降 is the aircraft climbing angle during descent;

[0023] Step (4): Based on the input variable pitch propeller take-off, climb, cruise, descent, and landing required thrust, the variable pitch propeller operating performance model, and the motor operating performance model, calculate the flight conditions corresponding to each flight stage of the aircraft and the comprehensive optimal efficiency operating point of the motor and propeller under the required thrust, and obtain the variable pitch propeller operating optimization variable u for each flight stage: take-off speed ω 螺旋桨-起飞, take-off pitch angle β 螺旋桨-起飞 、Climbing speedω 螺旋桨-爬升 , climbing pitch angle β 螺旋桨-爬升 , cruising speedω 螺旋桨-巡航 , cruise pitch angle β 螺旋桨-巡航 , reduce the speed ω 螺旋桨-下降 , pitch angle β 螺旋桨-下降 , Landing speed ω 螺旋桨-降落 , landing pitch angle β 螺旋桨-降落 ;

[0024] Variable pitch propeller operating performance model:

[0025]

[0026] In the formula, C T is the propeller lift coefficient, C P is the propeller power coefficient, ξ is the dimensionless radial position of each blade element of the propeller, hub is the dimensionless radial position of the propeller hub, c is the propeller chord length, N blades is the number of propeller blades, β ind is the induced flow angle, β ∞ is the free flow angle, C d is the blade airfoil drag coefficient, C l is the lift coefficient of the blade airfoil;

[0027] The free flow angle β of the blade element at position ξ ∞ With the induced flow angle β ind Calculated by solving the following equation:

[0028]

[0029] Where V ∞ is the free stream velocity, which is equal to the flight speed V of the aircraft during the flight of the aircraft, ω 螺旋桨 is the propeller speed, φ is the torsion angle, β 螺旋桨 is the propeller pitch angle, α is the blade airfoil angle of attack, C lα is the lift coefficient when the blade airfoil angle of attack is α, c is the chord length of the blade airfoil, φ tip is the blade tip twist angle;

[0030] The propeller operating conditions are calculated by the following formula:

[0031]

[0032] Where ρ is the air density, T 螺旋桨 is the propeller thrust, ω 螺旋桨 is the propeller speed, P 螺旋桨 is the propeller input power, Q螺旋桨 is the propeller torque;

[0033] Motor operation performance model:

[0034]

[0035] In the formula, a Q is the maximum torque coefficient of the motor, a P is the maximum power coefficient of the motor, a ω is the maximum speed coefficient of the motor, ω 电机 is the motor speed, Q 电机 is the motor torque, P 电机-损失 is the motor power loss, P 电机-输出 is the output mechanical work of the motor, P 电机 is the electrical power consumed by the motor, Q 电机-max is the maximum torque of the motor, P 电机-max is the maximum output power of the motor, ω 螺旋桨-max is the maximum speed of the motor, C 0 , C 1 , C 2 , C 3 is a constant term, and its expression is as follows:

[0036]

[0037] Where a is the fixed loss coefficient, which is η 电机-设计 The motor is designed for peak efficiency;

[0038] Assuming that the motor shaft and the propeller shaft are directly connected mechanically, the operating parameters of the motor and propeller satisfy the following relationship:

[0039]

[0040] Step (5): Calculate the constraints according to the input power system design variables, profile design variables and operation optimization variables, and determine whether the design constraints are met. If the constraints are not met, return to step (1) and reinitialize the parameters; if the constraints are met, proceed to step (6);

[0041] The design constraints are as follows:

[0042]

[0043] Where C Lmax is the maximum lift coefficient of the aircraft, f M空重 is the minimum mass fraction of empty weight, V 螺旋桨-tip is the rotation speed of the propeller blade tip, Ma is the Mach number;

[0044] Step (6): Input the power system design variable d, the profile design variable p and the operation optimization variable u into the range calculation model, calculate the range R of the vertical take-off and landing aircraft, and use f(d, p, u) = -R as the fitness function of the genetic algorithm;

[0045] The range calculation model is as follows:

[0046]

[0047] Where R is the range of the vertical take-off and landing vehicle, t 爬升-0 is the climbing start time, t 下降-f is the descent end time, V is the flight speed, γ is the climb angle, SE 电池 is the battery specific energy, t 起飞-0 is the take-off start time, t 降落-f is the landing end time, P 电池 Consumes power to the battery.

[0048] Step (7): Substitute the fitness function value f(d, p, u) obtained in step (6) into the genetic algorithm solver, and repeat steps (1) to (6), and substitute the difference between the two fitness function values ​​into step (8);

[0049] Step (8): When the difference between the fitness function values ​​input in step (7) is greater than the set tolerance ε, repeat steps (1) to (7); if the difference between the fitness function values ​​is less than the set tolerance ε, proceed to step (9);

[0050] Step (9): Optimization is completed, and the optimization design result Opt(d, p, u) is output to complete the joint optimization design of profile-operation-power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0052] Figure 1 A schematic diagram of a flow chart of a joint optimization design method for profile-operation-power system of an electric vertical take-off and landing aircraft provided in an embodiment of the present application; DETAILED DESCRIPTION

[0053] The following is combined with Figure 1 The present application is further described in detail through examples. The following examples are for explanation of the present application but the present application is not limited to the following examples.

[0054] Step (1): The design variables include the power system design variables d (including the motor design torque Q 电机-设计 、Motor design speedω 电机-设计 , propeller diameter d螺旋桨 、Number of battery packs 电池组 ) and profile design variables p (including climb speed V 爬升 , Cruising speed V 巡航 , descent speed V 下降 , cruising altitude h 巡航 ); within the design interval, each design variable randomly generates an initial value to complete the design variable initialization, the power system design variable is brought into step (2), and the profile design variable is brought into step (3); the following table gives the range of design variables selected in this implementation case:

[0055] Design variables symbol unit Lower Boundary Upper Boundary Motor design torque <![CDATA[Q 电机-设计 ]]> Nm 50 500 Motor design speed <![CDATA[ω 电机-设计 ]]> rpm 500 2000 Propeller diameter <![CDATA[d 螺旋桨 ]]> m 2 3 Number of battery packs <![CDATA[N 电池组 ]]> - 2 8 Climbing speed <![CDATA[V 爬升 ]]> m / s 50 100 Cruising speed <![CDATA[V 巡航 ]]> m / s 50 100 Descent speed <![CDATA[V 下降 ]]> m / s 50 100 Cruising altitude <![CDATA[h 巡航 ]]> m 1000 5000

[0056] Step (2): Calculate the power system mass (including the motor mass M) based on the input power system design variable d and the power system mass calculation model. 电机 、Battery quality M 电池 , propeller mass M 螺旋桨 ), and obtain the take-off mass MTOM of the aircraft, which is then brought into step (3); the formula for calculating the mass of the power system is as follows:

[0057] Battery quality model:

[0058] M 电池 =N 电池组 ·M 电池组 (27)

[0059] Where M 电池组 is the weight of a single battery pack;

[0060] Motor mass model:

[0061]

[0062] Where Q 电机-max is the maximum torque of the motor, SQ 电机 is the motor specific torque, P 电机-max is the maximum power of the motor, SP 电机 is the motor specific power;

[0063] Propeller mass model:

[0064]

[0065] Aircraft take-off mass:

[0066] MTOM=M 电池 +M 电机 +M 螺旋桨 +M 空重 (30)

[0067] Where M 空重is the empty weight of the aircraft (the rest of the weight of the aircraft excluding the power system); the following table gives the setting values ​​of the mass model parameters in this implementation case:

[0068] parameter symbol unit Value Weight of a single battery pack <![CDATA[M 电池组 ]]> kg 35 Motor specific torque <![CDATA[SQ 电机 ]]> Nm / kg 60 Motor specific power <![CDATA[SP 电机 ]]> kW / kg 3 Aircraft empty weight <![CDATA[M 空重 ]]> kg 160kg

[0069] Step (3): Calculate the vertical take-off and landing aircraft take-off thrust T according to the input profile design variable p, aircraft take-off mass MTOM and aircraft profile requirement analysis model 起飞 , Climbing Required Thrust T 爬升 , cruise required thrust T 巡航 , Decrease demand thrust T 下降 , Landing Required Thrust T 降落 ; According to the number of propellers N 螺旋桨 , calculate the takeoff thrust T required for a single variable pitch propeller 起飞-螺旋桨 , propeller climb required thrust T 爬升-螺旋桨 , propeller cruise required thrust T 巡航-螺旋桨 , propeller descent required thrust T 下降-螺旋桨 , propeller landing thrust required T 降落-螺旋桨 , bring into step (4); the aircraft profile demand analysis model is as follows:

[0070]

[0071] Where g is weight acceleration, S ref is the aircraft reference area, C D爬升 is the drag coefficient of the aircraft during climbing, C D巡航 is the drag coefficient of the aircraft during cruising, C D下降 is the drag coefficient of the aircraft during descent, C L爬升 is the lift coefficient of the aircraft during climbing, C L巡航 is the lift coefficient of the aircraft during cruising, C L下降 is the lift coefficient of the aircraft during descent, γ 爬升 is the aircraft climbing angle during climbing, γ 下降 is the aircraft climb angle during descent; the following table gives the specific parameters of the aircraft profile demand analysis model in this implementation case:

[0072] parameter symbol unit Value Weight acceleration g <![CDATA[kg·m / s 2 ]]> 9.8 Aircraft climbing angle during climbing <![CDATA[γ 爬升 ]]> deg 3 Aircraft climb angle during descent <![CDATA[γ 下降 ]]> deg -3 Aircraft reference area <![CDATA[S ref ]]> <![CDATA[m 2 ]]> 2

[0073] The relationship between lift coefficient and drag coefficient is:

[0074] Angle of attack -2 0 2 4 6 8 10 12 14 CL 0.335 0.546 0.759 0.971 1.152 1.341 1.491 1.6066 1.687 CD 0.046 0.053 0.0645 0.080 0.098 0.125 0.154 0.1897 0.236

[0075] Step (4): Based on the input variable pitch propeller take-off, climb, cruise, descent, and landing required thrust, the variable pitch propeller operating performance model, and the motor operating performance model, calculate the flight conditions corresponding to each flight stage of the aircraft and the comprehensive optimal efficiency operating point of the motor and propeller under the required thrust, and obtain the variable pitch propeller operating optimization variable u for each flight stage: take-off speed ω 螺旋桨-起飞 , take-off pitch angle β 螺旋桨-起飞 、Climbing speedω 螺旋桨-爬升 , climbing pitch angle β 螺旋桨-爬升 , cruising speedω 螺旋桨-巡航 , cruise pitch angle β 螺旋桨-巡航 , reduce the speed ω 螺旋桨-下降 , pitch angle β 螺旋桨-下降 , Landing speed ω 螺旋桨-降落 , landing pitch angle β 螺旋桨-降落 ;

[0076] Variable pitch propeller operating performance model:

[0077]

[0078] In the formula, C T is the propeller lift coefficient, C P is the propeller power coefficient, ξ is the dimensionless radial position of each blade element of the propeller, hub is the dimensionless radial position of the propeller hub, c is the propeller chord length, N blades is the number of propeller blades, β ind is the induced flow angle, β ∞ is the free flow angle, C d is the blade airfoil drag coefficient, C l is the lift coefficient of the blade airfoil;

[0079] The free flow angle β of the blade element at position ξ ∞ With the induced flow angle β ind Calculated by solving the following equation:

[0080]

[0081] Where V ∞ is the free stream velocity, which is equal to the flight speed V of the aircraft during the flight of the aircraft, ω 螺旋桨 is the propeller speed, φ is the torsion angle, β 螺旋桨 is the propeller pitch angle, α is the blade airfoil angle of attack, C lα is the lift coefficient when the blade airfoil angle of attack is α, c is the chord length of the blade airfoil, φ tip is the blade tip twist angle;

[0082] The propeller operating conditions are calculated by the following formula:

[0083]

[0084] Where ρ is the air density, T 螺旋桨 is the propeller thrust, ω 螺旋桨 is the propeller speed, P 螺旋桨 is the propeller input power, Q 螺旋桨 is the propeller torque; the following table gives the specific parameters of the propeller in this implementation case:

[0085]

[0086]

[0087] Motor operation performance model:

[0088]

[0089] In the formula, a Q is the maximum torque coefficient of the motor, a P is the maximum power coefficient of the motor, a ω is the maximum speed coefficient of the motor, ω 电机 is the motor speed, Q 电机 is the motor torque, P 电机-损失 is the motor power loss, P 电机-输出 is the output mechanical work of the motor, P 电机 is the electrical power consumed by the motor, Q 电机-max is the maximum torque of the motor, P 电机-max is the maximum output power of the motor, ω 螺旋桨-max is the maximum speed of the motor, C 0 , C 1 , C 2 , C 3 is a constant term, and its expression is as follows:

[0090]

[0091] Where a is the fixed loss coefficient, which is η 电机-设计 The motor design peak efficiency; the following table gives the specific parameters of the motor model in this implementation case:

[0092] parameter symbol unit Value Motor maximum torque coefficient <![CDATA[a Q ]]> - 2 Motor maximum power factor <![CDATA[a P ]]> - 1.8 Motor maximum speed coefficient <![CDATA[a ω ]]> - 2 Fixed loss factor a - 0.95 Motor design peak efficiency <![CDATA[η 电机-设计 ]]> - 0.94

[0093] Assuming that the motor shaft and the propeller shaft are directly connected mechanically, the operating parameters of the motor and propeller satisfy the following relationship:

[0094]

[0095] Step (5): Calculate the constraints according to the input power system design variables, profile design variables and operation optimization variables, and determine whether the design constraints are met. If the constraints are not met, return to step (1) and reinitialize the parameters; if the constraints are met, proceed to step (6);

[0096] The design constraints are as follows:

[0097]

[0098] Where C Lmax is the maximum lift coefficient of the aircraft, f M空重 is the minimum mass fraction of empty weight, V 螺旋桨-tip is the propeller blade tip speed, Ma is the Mach number; the following table gives the specific parameters of the design constraints in this implementation case:

[0099] parameter symbol unit Value Maximum lift coefficient of aircraft <![CDATA[C Lmax ]]> - 1.2 Minimum empty weight fraction <![CDATA[f M空重 ]]> - 0.4

[0100] Step (6): Input the power system design variable d, the profile design variable p and the operation optimization variable u into the range calculation model, calculate the range R of the vertical take-off and landing aircraft, and use f(d, p, u) = -R as the fitness function of the genetic algorithm;

[0101] The voyage calculation model is as follows:

[0102]

[0103] Where R is the range of the vertical take-off and landing aircraft, t 爬升-0 is the climbing start time, t 下降-f is the descent end time, V is the flight speed, γ is the climb angle, SE 电池 is the battery specific energy, t 起飞-0 is the take-off start time, t 降落-f is the landing end time, P 电池 Consumes power to the battery.

[0104] Step (7): Substitute the fitness function value f(d, p, u) obtained in step (6) into the genetic algorithm solver, and repeat steps (1) to (6), and substitute the difference between the two fitness function values ​​into step (8);

[0105] Step (8): When the difference between the fitness function values ​​input in step (7) is greater than the set tolerance ε, repeat steps (1) to (7); if the difference between the fitness function values ​​is less than the set tolerance ε, proceed to step (9);

[0106] Step (9): Optimization is completed, and the optimization design result Opt(d, p, u) is output, completing the joint optimization design of profile-operation-power system. The specific design results are as follows:

[0107]

[0108]

Claims

1. A profile-operation-component joint optimization design method for an electric vertical take-off and landing aircraft, characterized in that: The following steps are involved: Step (1): The design variables include the power system design variables d (including the motor design torque Q 电机-设计 、Motor design speedω 电机-设计 , propeller diameter d 螺旋桨 、Number of battery packs 电池组 ) and profile design variables p (including climb speed V 爬升 , Cruising speed V 巡航 , descent speed V 下降 , cruising altitude h 巡航 ); Within the design interval, each design variable randomly generates an initial value to complete the initialization of the design variables, the power system design variables are brought into step (2), and the profile design variables are brought into step (3); Step (2): Calculate the power system mass (including the motor mass M) based on the input power system design variable d and the power system mass calculation model. 电机 、Battery quality M 电池 , propeller mass M 螺旋桨 ), obtain the aircraft take-off mass MTOM, and bring it into step (3); Step (3): Calculate the vertical take-off and landing aircraft take-off thrust T according to the input profile design variable p, aircraft take-off mass MTOM and aircraft profile requirement analysis model 起飞 , Climbing Required Thrust T 爬升 , cruise required thrust T 巡航 , Decrease demand thrust T 下降 , Landing Required Thrust T 降落 ; According to the number of propellers N 螺旋桨 , calculate the takeoff thrust T required for a single variable pitch propeller 起飞-螺旋桨 , propeller climb required thrust T 爬升-螺旋桨 , propeller cruise required thrust T 巡航-螺旋桨 , propeller descent required thrust T 下降-螺旋桨 , propeller landing thrust required T 降落-螺旋桨 , bring it into step (4); Step (4): Based on the input variable pitch propeller take-off, climb, cruise, descent, and landing required thrust, the variable pitch propeller operating performance model, and the motor operating performance model, calculate the flight conditions corresponding to each flight stage of the aircraft and the comprehensive optimal efficiency operating point of the motor and propeller under the required thrust, and obtain the variable pitch propeller operating optimization variable u for each flight stage: take-off speed ω 螺旋桨-起飞 , take-off pitch angle β 螺旋桨-起飞 、Climbing speedω 螺旋桨-爬升 , climbing pitch angle β 螺旋桨-爬升 , cruising speedω 螺旋桨-巡航 , cruise pitch angle β 螺旋桨-巡航 , reduce the speed ω 螺旋桨-下降 , pitch angle β 螺旋桨-下降 , Landing speed ω 螺旋桨-降落 , landing pitch angle β 螺旋桨-降落 ; Step (5): Calculate the constraints according to the input power system design variables, profile design variables and operation optimization variables, and determine whether the design constraints are met. If the constraints are not met, return to step (1) and reinitialize the parameters; if the constraints are met, proceed to step (6); Step (6): Input the power system design variable d, the profile design variable p and the operation optimization variable u into the range calculation model, calculate the range R of the vertical take-off and landing aircraft, and use f(d, p, u) = -R as the fitness function of the genetic algorithm; Step (7): Substitute the fitness function value f(d, p, u) obtained in step (6) into the genetic algorithm solver, and repeat steps (1) to (6), and substitute the difference between the two fitness function values ​​into step (8); Step (8): When the difference between the fitness function values ​​input in step (7) is greater than the set tolerance ε, repeat steps (1) to (7); if the difference between the fitness function values ​​is less than the set tolerance ε, proceed to step (9); Step (9): Optimization is completed, and the optimization design result Opt(d, p, u) is output to complete the joint optimization design of profile-operation-power system.

2. The electric vertical take-off and landing aircraft profile-operation-component joint optimization design method according to claim 1 is characterized in that The power system mass calculation model described in step (2) is as follows: Battery quality model: M 电池 =N 电池组 ·M 电池组 (1) Where M 电池组 is the weight of a single battery pack; Motor mass model: Where Q 电机-max is the maximum torque of the motor, SQ 电机 is the motor specific torque, P 电机-max is the maximum power of the motor, SP 电机 is the motor specific power; Propeller mass model: Aircraft take-off mass: MTOM=M 电池 +M 电机 +M 螺旋桨 +M 空重 (4) Where M 空重 is the empty weight of the aircraft (the rest of the weight of the aircraft excluding the power system).

3. The profile-operation-component joint optimization design method of an electric vertical take-off and landing aircraft according to claim 1 is characterized in that The aircraft profile requirement analysis model described in step (3) is as follows: Where g is weight acceleration, S ref is the aircraft reference area, C D爬升 is the drag coefficient of the aircraft during climbing, C D巡航 is the drag coefficient of the aircraft during cruising, C D下降 is the drag coefficient of the aircraft during descent, C L爬升 is the lift coefficient of the aircraft during climbing, C L巡航 is the lift coefficient of the aircraft during cruising, C L下降 is the lift coefficient of the aircraft during descent, γ 爬升 is the aircraft climbing angle during climbing, γ 下降 It is the climb angle of the aircraft during descent.

4. The electric vertical take-off and landing aircraft profile-operation-component joint optimization design method according to claim 1 is characterized in that The variable pitch propeller operation performance model and the motor operation performance model described in step (4) are respectively as follows: Variable pitch propeller operating performance model: In the formula, C T is the propeller lift coefficient, C P is the propeller power coefficient, ξ is the dimensionless radial position of each blade element of the propeller, hub is the dimensionless radial position of the propeller hub, c is the propeller chord length, N blades is the number of propeller blades, β ind is the induced flow angle, β ∞ is the free flow angle, C d is the blade airfoil drag coefficient, C l is the lift coefficient of the blade airfoil; The free flow angle β of the blade element at position ξ ∞ With the induced flow angle β ind Calculated by solving the following equation: Where V ∞ is the free stream velocity, which is equal to the flight speed V of the aircraft during the flight of the aircraft, ω 螺旋桨 is the propeller speed, φ is the torsion angle, β 螺旋桨 is the propeller pitch angle, α is the blade airfoil angle of attack, C lα is the lift coefficient when the blade airfoil angle of attack is α, c is the chord length of the blade airfoil, φ tip is the blade tip twist angle; The operating conditions of the propeller are calculated by the following formula: Where ρ is the air density, T 螺旋桨 is the propeller thrust, ω 螺旋桨 is the propeller speed, P 螺旋桨 is the propeller input power, Q 螺旋桨 is the propeller torque; Motor operation performance model: In the formula, a Q is the maximum torque coefficient of the motor, a P is the maximum power coefficient of the motor, a ω is the maximum speed coefficient of the motor, ω 电机 is the motor speed, Q 电机 is the motor torque, P 电机-损失 is the motor power loss, P 电机-输出 is the output mechanical work of the motor, P 电机 is the electrical power consumed by the motor, Q 电机-max is the maximum torque of the motor, P 电机-max is the maximum output power of the motor, ω 螺旋桨-max is the maximum speed of the motor, C0, C1, C2, C3 are constant terms, and their expressions are as follows: Where a is the fixed loss coefficient, which is η 电机-设计 The motor is designed for peak efficiency; Assuming that the motor shaft and the propeller shaft are directly connected mechanically, the operating parameters of the motor and propeller satisfy the following relationship:

5. The electric vertical take-off and landing aircraft profile-operation-component joint optimization design method according to claim 1 is characterized in that The design constraints described in step (5) are as follows: Where C Lmax is the maximum lift coefficient of the aircraft, f M空重 is the minimum mass fraction of empty weight, V 螺旋桨-tip is the rotation speed of the propeller blade tip and Ma is the Mach number.

6. The electric vertical take-off and landing aircraft profile-operation-component joint optimization design method according to claim 1 is characterized in that The range calculation model described in step (6) is as follows: Where R is the range of the vertical take-off and landing vehicle, t 爬升-0 is the climbing start time, t 下降-f is the descent end time, V is the flight speed, γ is the climb angle, SE 电池 is the battery specific energy, t 起飞-0 is the take-off start time, t 降落-f is the landing end time, P 电池 Consumes power to the battery.

Images