Wheel type take-off and landing solar aircraft windless take-off performance engineering estimation method and device

Abstract

The embodiment of the invention discloses a wind-free take-off performance engineering estimation method and device for a wheel type take-off and landing solar aircraft. The method comprises the following steps: (1) inputting initial values of all parameters when the aircraft stops; (2) calculating aerodynamic performance of the aircraft, wherein lift force, resistance, pitching moment and propeller tension of the aircraft are calculated; (3) undercarriage state calculation: undercarriage supporting force, elongation and wing spar torsion angle; (4) calculating the pitch angle of the aircraft; (5) calculating the takeoff performance of the aircraft, wherein the accumulative taxiing distance and airspeed of the aircraft during front-start off-ground, the accumulative taxiing distance and airspeed of the aircraft during main-start off-ground, the pitch angle of the aircraft, the airspeed and the undercarriage supporting force change along with time; and (6) evaluating the take-off performance. The method is simple, convenient and rapid in calculation, has a good matching degree with an actual flight test, and can provide technical support for performance evaluation of the take-off process of the wheel type take-off and landing solar aircraft.

Description

Technical Field

[0001] This invention relates to the field of aircraft design, and particularly to an engineering estimation method for the windless takeoff performance of a wheeled solar-powered takeoff and landing aircraft. Background Technology

[0002] Solar-powered aircraft are a novel long-endurance near-space flight platform capable of performing multiple functions of low-Earth orbit satellites, including reconnaissance and surveillance, communication services, and remote sensing mapping. Compared to traditional satellites, these aircraft offer significant advantages such as flexible deployment and low operating costs; while compared to conventional aircraft, they exhibit unique performance characteristics such as ultra-long endurance, long range, and long-term loitering in specific areas. Unlike traditional fixed-wing aircraft, solar-powered aircraft convert solar energy into electricity to drive motors through a photovoltaic conversion system. To meet the mission requirements of low power consumption and high-altitude long endurance, these aircraft typically employ lightweight designs, resulting in low structural mass density and low wing loading. During takeoff and taxiing, significant deformation occurs due to the coupling effect of aerodynamic loads and structural deformation. Therefore, in-depth research on their takeoff characteristics and performance under windless conditions is of significant engineering importance.

[0003] Currently, the takeoff performance prediction of wheeled takeoff and landing solar-powered aircraft mainly relies on two methods: computer simulation and scaled-down model verification. The former suffers from large calculation errors and long cycles, while the latter, although more accurate, also faces the problems of long cycles and high costs. The engineering estimation method proposed in this paper has been verified by actual flight tests, showing good agreement, short cycle, and high efficiency, and can provide reliable technical support for the takeoff performance evaluation of wheeled takeoff and landing solar-powered aircraft. Therefore, it is essential to propose an engineering estimation method for the windless takeoff performance of wheeled takeoff and landing solar-powered aircraft. Summary of the Invention

[0004] To address the shortcomings of the aforementioned methods for predicting the takeoff performance of wheeled solar-powered aircraft, this invention provides an engineering estimation method and apparatus for the windless takeoff performance of wheeled solar-powered aircraft, based on the problems of existing takeoff performance prediction methods.

[0005] In a first aspect, embodiments of this application provide an engineering estimation method for the windless takeoff performance of a wheeled solar-powered aircraft, including: Step S01: Input the initial values ​​of various parameters when the aircraft is stopped, including: environmental physical parameters, overall aircraft parameters, aircraft elevator partial derivative parameters, propulsion subsystem parameters, landing gear parameters, and initial values ​​for takeoff performance calculation; Step S02, perform aerodynamic performance calculations on the aircraft, including calculating the lift, drag, pitch moment, and propeller thrust of the aircraft; Step S03, calculate the landing gear condition, including calculating the landing gear support force, landing gear extension, and wing sparsity torsion angle; Step S04, calculate the pitch angle of the aircraft; Step S05, perform takeoff performance calculations on the aircraft; Step S06, evaluate the takeoff performance of the aircraft.

[0006] Specifically, step S02 further includes: lift, drag, and pitching moment are calculated from dynamic pressure, corresponding dimensionless coefficients, wing reference chord length, and wing reference area, including: The lift and pitch moment coefficients are corrected by the partial derivatives of the aircraft's elevator, and the drag coefficient is fitted using a quadratic polynomial of the aircraft's angle of attack. Elevator input is given by the taxiing control law based on the aircraft's pitch angle; propeller thrust is calculated by the flight control data table based on a fitting formula for airspeed and engine speed. .

[0007] Specifically, step S03 further includes: The landing gear elongation is calculated from the theoretical landing gear elongation, the aircraft pitch angle, the spar torsion angle, and the landing gear compression, including: The landing compression is calculated using a fitting formula obtained from landing gear loading tests and landing gear support force. Before the nose lift takes off, the landing gear support force is calculated from the propeller thrust, the height of the propeller thrust line, aircraft drag, friction, gravity, lift, pitch moment, distance from the center of gravity to the main landing gear touchdown point, and distance from the center of gravity to the aerodynamic focus. After the front lift takes off and before the main lift takes off, the support force of the front lift is zero, and the support force of the main lift is calculated from the aircraft's gravity and lift. The wing sparb torsion angle is calculated from the landing gear support force, friction force, elongation, forward extension angle, aircraft pitch angle, and pitch rotation inertia around the sparb.

[0008] Specifically, including: The wing sparb torsion angle is set to the value when the aircraft is parked on the ground.

[0009] Specifically, step S04 further includes: Before the nose lift takes off, the aircraft's pitch angle is calculated from the landing gear extension, the forward extension angle, the distance between the main lift and the nose lift's touchdown point, and the spar twist angle; after the nose lift takes off and before the main lift takes off, the aircraft's pitch angle is calculated from the pitch angle calculated at the previous calculation point, the pitch acceleration, and the time interval. Specifically, including: Pitch acceleration is calculated from propeller thrust, propeller thrust line height, aircraft drag, gravity, distance from center of gravity to main takeoff touchdown point, aerodynamic torque, lift, distance from aerodynamic focus to center of gravity, and pitch moment of inertia about main takeoff touchdown point. Specifically, including: Compare the updated pitch angle value of the aircraft with the calculated pitch angle value at the previous calculation point. If the difference is less than 0.001, update the pitch angle and calculate the aircraft's taxiing performance; otherwise, return to step S02.

[0010] Specifically, step S05 further includes: The cumulative taxiing distance and airspeed of the aircraft when the front takeoff is off the ground, the airspeed and cumulative taxiing distance of the aircraft when the main takeoff is off the ground, the pitch angle, airspeed and landing gear support force of the aircraft are calculated over time. If the dimensionless landing gear support force is less than 0.001, the landing gear is determined to be off the ground, and a takeoff performance evaluation is performed; otherwise, return to step S02.

[0011] Specifically, including: The cumulative taxiing distance of the aircraft is calculated from the aircraft's ground speed and the cumulative taxiing distance at the previous calculation point: Aircraft airspeed is calculated from aircraft acceleration and airspeed at the previous calculation point: The acceleration of an aircraft is calculated from the propeller thrust, aircraft drag, and landing gear friction. After the lead lift takes off and before the main lift takes off, the friction of the lead lift is zero, and the acceleration of the aircraft is: Store the aircraft's taxiing time, pitch angle, airspeed, and landing gear support force at every moment.

[0012] Secondly, embodiments of this application provide an engineering estimation device for the windless takeoff performance of a wheeled solar-powered aircraft, comprising: The system includes an input module for inputting initial values ​​of various parameters when the aircraft is stopped, including: environmental physical parameters, overall aircraft parameters, elevator partial derivative parameters, propulsion subsystem parameters, landing gear parameters, and initial values ​​for takeoff performance calculations; an aerodynamic performance calculation module for calculating the aerodynamic performance of the aircraft, including: calculating the aircraft's lift, drag, pitch moment, and propeller thrust; a landing gear status calculation module for calculating the landing gear status, including: calculating the landing gear support force, landing gear extension, and wing sparsity twist angle; a pitch angle calculation module for calculating the aircraft's pitch angle; a takeoff performance calculation module for calculating the aircraft's takeoff performance; and a takeoff performance evaluation module for evaluating the aircraft's takeoff performance.

[0013] Specifically, the aerodynamic performance calculation module further includes: Lift, drag, and pitching moment are calculated from dynamic pressure, corresponding dimensionless coefficients, wing reference chord length, and wing reference area, including: The lift and pitch moment coefficients are corrected by the partial derivatives of the aircraft's elevator, and the drag coefficient is fitted using a quadratic polynomial of the aircraft's angle of attack. The elevator control amount is given by the taxiing control law based on the aircraft's pitch angle; The propeller thrust is calculated from the flight control data sheet using a fitting formula based on airspeed and engine speed. .

[0014] Specifically, the landing gear status calculation module further includes: The landing gear elongation is calculated from the theoretical landing gear elongation, the aircraft pitch angle, the spar torsion angle, and the landing gear compression, including: The landing compression is calculated using a fitting formula obtained from landing gear loading tests and landing gear support force. Before the nose lift takes off, the landing gear support force is calculated from the propeller thrust, the height of the propeller thrust line, aircraft drag, friction, gravity, lift, pitch moment, distance from the center of gravity to the main landing gear touchdown point, and distance from the center of gravity to the aerodynamic focus. After the front lift takes off and before the main lift takes off, the support force of the front lift is zero, and the support force of the main lift is calculated from the aircraft's gravity and lift. The wing sparb torsion angle is calculated from the landing gear support force, friction force, elongation, forward extension angle, aircraft pitch angle, and pitch rotation inertia around the sparb.

[0015] Specifically, including: The wing sparb torsion angle is set to the value when the aircraft is parked on the ground.

[0016] Specifically, the pitch angle calculation module further includes: Before the nose lift takes off, the aircraft's pitch angle is calculated from the landing gear extension, the forward extension angle, the distance between the main lift and the nose lift's touchdown point, and the spar twist angle; after the nose lift takes off and before the main lift takes off, the aircraft's pitch angle is calculated from the pitch angle calculated at the previous calculation point, the pitch acceleration, and the time interval. Specifically, including: Pitch acceleration is calculated from propeller thrust, propeller thrust line height, aircraft drag, gravity, distance from center of gravity to main takeoff touchdown point, aerodynamic torque, lift, distance from aerodynamic focus to center of gravity, and pitch moment of inertia about main takeoff touchdown point. Specifically, including: Compare the updated pitch angle value of the aircraft with the calculated pitch angle value at the previous calculation point. If the difference is less than 0.001, update the pitch angle and calculate the aircraft's taxiing performance; otherwise, return to step S02.

[0017] Specifically, the takeoff performance calculation module further includes: The cumulative taxiing distance and airspeed of the aircraft when the front takeoff is off the ground, the airspeed and cumulative taxiing distance of the aircraft when the main takeoff is off the ground, the pitch angle, airspeed and landing gear support force of the aircraft are calculated over time. If the dimensionless landing gear support force is less than 0.001, the landing gear is determined to be off the ground, and a takeoff performance evaluation is performed; otherwise, return to step S02.

[0018] Specifically, including: The cumulative taxiing distance of the aircraft is calculated from the aircraft's ground speed and the cumulative taxiing distance at the previous calculation point: Aircraft airspeed is calculated from aircraft acceleration and airspeed at the previous calculation point: The acceleration of an aircraft is calculated from the propeller thrust, aircraft drag, and landing gear friction. After the lead lift takes off and before the main lift takes off, the friction of the lead lift is zero, and the acceleration of the aircraft is: Store the aircraft's taxiing time, pitch angle, airspeed, and landing gear support force at every moment.

[0019] This invention discloses a method for evaluating takeoff performance by importing initial values ​​of various parameters when the aircraft is stopped; calculating the aircraft's aerodynamic performance, landing gear status, pitch angle, and takeoff performance. It utilizes flight control data tables and rudder effect data provided by aerodynamics experts to flight control professionals to estimate the solar-powered takeoff performance of wheeled aircraft. Without increasing workload, it yields calculation results with good agreement with actual flight tests, providing technical support for performance evaluation during takeoff, including but not limited to: a) avoiding excessive airspeed and accidental takeoff; b) using strain gauges on the landing gear to measure landing gear support force and angle sensors on the wing spars to measure wing spar twist angle, cross-validating and verifying for deviations in aerodynamic and structural design. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the engineering estimation method for the windless takeoff performance of a wheeled solar-powered aircraft according to an embodiment of the present invention. Detailed Implementation

[0021] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] Combination Figure 1 The method for estimating the windless takeoff performance of the wheeled solar-powered aircraft shown in this embodiment is illustrated below. Figure 1 This is a flowchart of one embodiment of the engineering estimation method for the windless takeoff performance of a wheeled solar-powered aircraft provided in this application.

[0024] Step S01: Input the initial values ​​of each parameter when the aircraft is stopped; Specifically, the initial values ​​of various parameters when the aircraft is stopped include: environmental physical parameters, overall aircraft parameters, aircraft elevator partial derivative parameters, propulsion subsystem parameters, landing gear parameters, and initial values ​​for takeoff performance calculations.

[0025] The environmental physical parameters include: air density ρ, gravitational acceleration g, and wheeled landing gear friction coefficient μ.

[0026] The overall parameters of the aircraft include: takeoff weight m, wing reference chord c, wing reference area S, and longitudinal distance from the center of gravity to the aerodynamic focus. The pitch inertia of the aircraft about its main takeoff and landing point Pitch inertia of the aircraft about the wing spars .

[0027] The partial derivative parameters of the aircraft elevator include: the partial derivative of the lift coefficient with respect to the elevator. The partial derivative of the pitch moment coefficient with respect to the elevator .

[0028] The propulsion subsystem parameters include: propeller speed Ω, propeller thrust line height. .

[0029] The landing gear parameters include: the longitudinal distance from the front landing point to the center of gravity. Longitudinal distance from the center of gravity to the main grounding point The forward extension angle of the front beam relative to the main beam The forward extension angle of the main beam relative to the main beam .

[0030] The initial values ​​for takeoff performance calculation include: sparsity twist angle. Theoretical elongation of the front end Theoretical elongation Glide time t, pitch angle Pitch angle determination value Pitch rate q, pitch acceleration Airspeed V, taxiing distance d.

[0031] Step S02: Perform aerodynamic performance calculations on the aircraft; Specifically, the aerodynamic performance calculations for the aircraft include: calculating the lift, drag, pitching moment, and propeller thrust of the aircraft.

[0032] The lift, drag, and pitching moment are calculated from dynamic pressure, corresponding dimensionless coefficients, the wing reference chord length, and the wing reference area, including: The lift and pitch moment coefficients are corrected by the partial derivatives of the aircraft's elevator, and the drag coefficient is fitted using a quadratic polynomial of the aircraft's angle of attack, including: The elevator control amount (de) is given by the taxiing control law based on the aircraft's pitch angle.

[0033] The propeller thrust mentioned is calculated from the flight control data sheet using a fitting formula based on airspeed and engine speed, including: Step S03: Calculate the landing gear status; Specifically, the calculation of the landing gear condition includes: landing gear support force, landing gear elongation, and wing spars twist angle.

[0034] The landing gear elongation is calculated from the theoretical landing gear elongation, the aircraft pitch angle, the spar torsion angle, and the landing gear compression, including: The landing compression is calculated using a fitting formula obtained from landing gear loading tests and the landing gear support force, including: Before the front takeoff, the landing gear support force is calculated from the propeller thrust, the height of the propeller thrust line, the aircraft drag, friction, gravity, lift, pitching moment, the distance from the center of gravity to the main takeoff touchdown point, and the distance from the center of gravity to the aerodynamic focus. After the front lift takes off and before the main lift takes off, the support force of the front lift is zero, and the support force of the main lift is calculated from the aircraft's gravity and lift. The wing sparb torsion angle is calculated from the landing gear support force, friction, elongation, forward extension angle, aircraft pitch angle, and pitch rotational inertia around the sparb. Optionally, the sparb has high torsional stiffness and small torsion angle variation; the torsion angle can be set to the value when the aircraft is parked on the ground.

[0035] Step S04: Calculate the pitch angle of the aircraft.

[0036] Specifically, before the front takeoff, the aircraft's pitch angle is calculated from the landing gear extension, the forward extension angle, the distance between the main takeoff and the front takeoff touchdown point, and the spar torsion angle; after the front takeoff and before the main takeoff, the aircraft's pitch angle is calculated from the pitch angle calculated at the previous calculation point, the pitch angle acceleration, and the time interval. Pitch acceleration is calculated from propeller thrust, propeller thrust line height, aircraft drag, gravity, distance from center of gravity to main takeoff and landing point, aerodynamic torque, lift, distance from aerodynamic focus to center of gravity, and pitch rotational inertia about the main takeoff and landing point. The updated pitch angle value of the aircraft is compared with the pitch angle calculated at the previous calculation point. If the difference is less than 0.001, the pitch angle is updated and the aircraft's taxiing performance is calculated. Otherwise, the aircraft's aerodynamic performance, landing gear status, and pitch angle are recalculated.

[0037] Step S05: Calculate the takeoff performance of the aircraft; Specifically, the takeoff performance calculation of the aircraft includes: the cumulative taxiing distance and airspeed of the aircraft when the front takeoff lifts off the ground, the airspeed and cumulative taxiing distance of the aircraft when the main takeoff lifts off the ground, and the changes of the aircraft's pitch angle, airspeed, and landing gear support force over time. The cumulative taxiing distance of the aircraft is calculated from the aircraft's ground speed and the cumulative taxiing distance at the previous calculation point: Aircraft airspeed is calculated from aircraft acceleration and airspeed at the previous calculation point: The acceleration of an aircraft is calculated from the propeller thrust, aircraft drag, and landing gear friction. After the lead lift takes off and before the main lift takes off, the friction of the lead lift is zero, and the acceleration of the aircraft is: Store the aircraft's taxiing time, pitch angle, airspeed, and landing gear support force at every moment; If the dimensionless landing gear support force is less than 0.001, the landing gear is determined to be off the ground, and a takeoff performance evaluation is performed; otherwise, return to step S02.

[0038] Step S06: Evaluate the takeoff performance of the aircraft.

[0039] Furthermore, this application provides an engineering estimation device for the windless takeoff performance of a wheeled solar-powered aircraft, as described in the embodiments of this application, specifically including: The input module is used to input the initial values ​​of various parameters when the aircraft is stopped; Specifically, the initial values ​​of various parameters when the aircraft is stopped include: environmental physical parameters, overall aircraft parameters, aircraft elevator partial derivative parameters, propulsion subsystem parameters, landing gear parameters, and initial values ​​for takeoff performance calculations.

[0040] The environmental physical parameters include: air density ρ, gravitational acceleration g, and wheeled landing gear friction coefficient μ.

[0041] The overall parameters of the aircraft include: takeoff weight m, wing reference chord c, wing reference area S, and longitudinal distance from the center of gravity to the aerodynamic focus. The pitch inertia of the aircraft about its main takeoff and landing point Pitch inertia of the aircraft about the wing spars .

[0042] The partial derivative parameters of the aircraft elevator include: the partial derivative of the lift coefficient with respect to the elevator. The partial derivative of the pitch moment coefficient with respect to the elevator .

[0043] The propulsion subsystem parameters include: propeller speed Ω, propeller thrust line height. .

[0044] The landing gear parameters include: the longitudinal distance from the front landing point to the center of gravity. Longitudinal distance from the center of gravity to the main grounding point The forward extension angle of the front beam relative to the main beam The forward extension angle of the main beam relative to the main beam .

[0045] The initial values ​​for takeoff performance calculation include: sparsity twist angle. Theoretical elongation of the front end Theoretical elongation Glide time t, pitch angle Pitch angle determination value Pitch rate q, pitch acceleration Airspeed V, taxiing distance d.

[0046] An aerodynamic performance calculation module is used to perform aerodynamic performance calculations on the aircraft. Specifically, the aerodynamic performance calculations for the aircraft include: calculating the lift, drag, pitching moment, and propeller thrust of the aircraft.

[0047] The lift, drag, and pitching moment are calculated from dynamic pressure, corresponding dimensionless coefficients, the wing reference chord length, and the wing reference area, including: The lift and pitch moment coefficients are corrected by the partial derivatives of the aircraft's elevator, and the drag coefficient is fitted using a quadratic polynomial of the aircraft's angle of attack, including: The elevator control amount (de) is given by the taxiing control law based on the aircraft's pitch angle.

[0048] The propeller thrust mentioned is calculated from the flight control data sheet using a fitting formula based on airspeed and engine speed, including: The landing gear status calculation module is used to calculate the landing gear status. Specifically, the calculation of the landing gear condition includes: landing gear support force, landing gear elongation, and wing spars twist angle.

[0049] The landing gear elongation is calculated from the theoretical landing gear elongation, the aircraft pitch angle, the spar torsion angle, and the landing gear compression, including: The landing compression is calculated using a fitting formula obtained from landing gear loading tests and the landing gear support force, including: Before the front takeoff, the landing gear support force is calculated from the propeller thrust, the height of the propeller thrust line, the aircraft drag, friction, gravity, lift, pitching moment, the distance from the center of gravity to the main takeoff touchdown point, and the distance from the center of gravity to the aerodynamic focus. After the front lift takes off and before the main lift takes off, the support force of the front lift is zero, and the support force of the main lift is calculated from the aircraft's gravity and lift. The wing sparb torsion angle is calculated from the landing gear support force, friction, elongation, forward extension angle, aircraft pitch angle, and pitch rotational inertia around the sparb. Optionally, the sparb has high torsional stiffness and small torsion angle variation; the torsion angle can be set to the value when the aircraft is parked on the ground.

[0050] The pitch angle calculation module is used to calculate the pitch angle of the aircraft.

[0051] Specifically, before the front takeoff, the aircraft's pitch angle is calculated from the landing gear extension, the forward extension angle, the distance between the main takeoff and the front takeoff touchdown point, and the spar torsion angle; after the front takeoff and before the main takeoff, the aircraft's pitch angle is calculated from the pitch angle calculated at the previous calculation point, the pitch angle acceleration, and the time interval. Pitch acceleration is calculated from propeller thrust, propeller thrust line height, aircraft drag, gravity, distance from center of gravity to main takeoff and landing point, aerodynamic torque, lift, distance from aerodynamic focus to center of gravity, and pitch rotational inertia about the main takeoff and landing point. The updated pitch angle value of the aircraft is compared with the pitch angle calculated at the previous calculation point. If the difference is less than 0.001, the pitch angle is updated and the aircraft's taxiing performance is calculated. Otherwise, the aircraft's aerodynamic performance, landing gear status, and pitch angle are recalculated.

[0052] A takeoff performance calculation module is used to calculate the takeoff performance of the aircraft. Specifically, the takeoff performance calculation of the aircraft includes: the cumulative taxiing distance and airspeed of the aircraft when the front takeoff lifts off the ground, the airspeed and cumulative taxiing distance of the aircraft when the main takeoff lifts off the ground, and the changes of the aircraft's pitch angle, airspeed, and landing gear support force over time. The cumulative taxiing distance of the aircraft is calculated from the aircraft's ground speed and the cumulative taxiing distance at the previous calculation point: Aircraft airspeed is calculated from aircraft acceleration and airspeed at the previous calculation point: The acceleration of an aircraft is calculated from the propeller thrust, aircraft drag, and landing gear friction. After the lead lift takes off and before the main lift takes off, the friction of the lead lift is zero, and the acceleration of the aircraft is: Store the aircraft's taxiing time, pitch angle, airspeed, and landing gear support force at every moment; If the dimensionless landing gear support force is less than 0.001, the landing gear is determined to be off the ground, and a takeoff performance evaluation is performed; otherwise, return to step S02.

[0053] The takeoff performance evaluation module is used to evaluate the takeoff performance of the aircraft.

[0054] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between apparatuses or units through some interfaces, and may be electrical, mechanical, or other forms.

[0055] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0056] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0057] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0058] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. An engineering estimation method for the windless takeoff performance of a wheeled solar-powered aircraft, comprising: Step S01: Input the initial values ​​of various parameters when the aircraft is stopped, including: environmental physical parameters, overall aircraft parameters, aircraft elevator partial derivative parameters, propulsion subsystem parameters, landing gear parameters, and initial values ​​for takeoff performance calculation; Step S02, perform aerodynamic performance calculations on the aircraft, including: calculating the lift, drag, pitching moment and propeller thrust of the aircraft; Step S03: Calculate the landing gear status, including: landing gear support force, landing gear elongation, and wing sparsity torsion angle. Step S04: Calculate the pitch angle of the aircraft; Step S05: Calculate the takeoff performance of the aircraft; Step S06: Evaluate the takeoff performance of the aircraft.

2. The method according to claim 1, wherein step S02 further comprises: Lift, drag, and pitching moment are calculated from dynamic pressure, corresponding dimensionless coefficients, wing reference chord length, and wing reference area, including: The lift and pitch moment coefficients are corrected by the partial derivatives of the aircraft's elevator, and the drag coefficient is fitted using a quadratic polynomial of the aircraft's angle of attack. The elevator control amount is given by the taxiing control law based on the aircraft's pitch angle; The propeller thrust is calculated from the flight control data sheet using a fitting formula based on airspeed and engine speed. 。 3. The method according to claim 1, wherein step S03 further comprises: The landing gear elongation is calculated from the theoretical landing gear elongation, the aircraft pitch angle, the spar torsion angle, and the landing gear compression, including: The landing compression is calculated using a fitting formula obtained from landing gear loading tests and landing gear support force. Before the nose lift takes off, the landing gear support force is calculated from the propeller thrust, the height of the propeller thrust line, aircraft drag, friction, gravity, lift, pitch moment, distance from the center of gravity to the main landing gear touchdown point, and distance from the center of gravity to the aerodynamic focus. After the front lift takes off and before the main lift takes off, the support force of the front lift is zero, and the support force of the main lift is calculated from the aircraft's gravity and lift. The wing sparb torsion angle is calculated from the landing gear support force, friction force, elongation, forward extension angle, aircraft pitch angle, and pitch rotation inertia around the sparb.

4. The method according to claim 3, comprising: The wing sparb torsion angle is set to the value when the aircraft is parked on the ground.

5. The method according to claim 1, wherein step S04 further comprises: Before the nose lift takes off, the aircraft's pitch angle is calculated from the landing gear extension, the forward extension angle, the distance between the main lift and the nose lift's touchdown point, and the spar twist angle; after the nose lift takes off and before the main lift takes off, the aircraft's pitch angle is calculated from the pitch angle calculated at the previous calculation point, the pitch acceleration, and the time interval. 。 6. The method according to claim 5, comprising: Pitch acceleration is calculated from propeller thrust, propeller thrust line height, aircraft drag, gravity, distance from center of gravity to main takeoff touchdown point, aerodynamic torque, lift, distance from aerodynamic focus to center of gravity, and pitch moment of inertia about main takeoff touchdown point. 。 7. The method according to claim 5, comprising: Compare the updated pitch angle value of the aircraft with the calculated pitch angle value at the previous calculation point. If the difference is less than 0.001, update the pitch angle and calculate the aircraft's taxiing performance; otherwise, return to step S02.

8. The method according to claim 1, wherein step S05 further comprises: The cumulative taxiing distance and airspeed of the aircraft when the front takeoff is off the ground, the airspeed and cumulative taxiing distance of the aircraft when the main takeoff is off the ground, the pitch angle, airspeed and landing gear support force of the aircraft are calculated over time. If the dimensionless landing gear support force is less than 0.001, the landing gear is determined to be off the ground, and a takeoff performance evaluation is performed; otherwise, return to step S02.

9. The method of claim 8, comprising: The cumulative taxiing distance of the aircraft is calculated from the aircraft's ground speed and the cumulative taxiing distance at the previous calculation point: Aircraft airspeed is calculated from aircraft acceleration and airspeed at the previous calculation point: The acceleration of an aircraft is calculated from the propeller thrust, aircraft drag, and landing gear friction. After the lead lift takes off and before the main lift takes off, the friction of the lead lift is zero, and the acceleration of the aircraft is: Store the aircraft's taxiing time, pitch angle, airspeed, and landing gear support force at every moment.

10. An engineering estimation device for the windless takeoff performance of a wheeled solar-powered aircraft, comprising: The input module is used to input the initial values ​​of various parameters when the aircraft is stopped, including: environmental physical parameters, overall aircraft parameters, aircraft elevator partial derivative parameters, propulsion subsystem parameters, landing gear parameters, and initial values ​​for takeoff performance calculations. The aerodynamic performance calculation module is used to perform aerodynamic performance calculations on the aircraft, including: calculating the lift, drag, pitching moment and propeller thrust of the aircraft; The landing gear status calculation module is used to calculate the landing gear status, including: landing gear support force, landing gear elongation, and wing sparsity torsion angle. The pitch angle calculation module is used to calculate the pitch angle of the aircraft. A takeoff performance calculation module is used to calculate the takeoff performance of the aircraft. The takeoff performance evaluation module is used to evaluate the takeoff performance of the aircraft.

11. The apparatus according to claim 10, wherein the aerodynamic performance calculation module further comprises: Lift, drag, and pitching moment are calculated from dynamic pressure, corresponding dimensionless coefficients, wing reference chord length, and wing reference area, including: The lift and pitch moment coefficients are corrected by the partial derivatives of the aircraft's elevator, and the drag coefficient is fitted using a quadratic polynomial of the aircraft's angle of attack. The elevator control amount is given by the taxiing control law based on the aircraft's pitch angle; The propeller thrust is calculated from the flight control data sheet using a fitting formula based on airspeed and engine speed. 。 12. The apparatus according to claim 10, wherein the landing gear state calculation module further comprises: The landing gear elongation is calculated from the theoretical landing gear elongation, the aircraft pitch angle, the spar torsion angle, and the landing gear compression, including: The landing compression is calculated using a fitting formula obtained from landing gear loading tests and landing gear support force. Before the nose lift takes off, the landing gear support force is calculated from the propeller thrust, the height of the propeller thrust line, aircraft drag, friction, gravity, lift, pitch moment, distance from the center of gravity to the main landing gear touchdown point, and distance from the center of gravity to the aerodynamic focus. After the front lift takes off and before the main lift takes off, the support force of the front lift is zero, and the support force of the main lift is calculated from the aircraft's gravity and lift. The wing sparb torsion angle is calculated from the landing gear support force, friction force, elongation, forward extension angle, aircraft pitch angle, and pitch rotation inertia around the sparb.

13. The apparatus of claim 12, comprising: The wing sparb torsion angle is set to the value when the aircraft is parked on the ground.

14. The apparatus according to claim 10, wherein the pitch angle calculation module further comprises: Before the nose lift takes off, the aircraft's pitch angle is calculated from the landing gear extension, the forward extension angle, the distance between the main lift and the nose lift's touchdown point, and the spar twist angle; after the nose lift takes off and before the main lift takes off, the aircraft's pitch angle is calculated from the pitch angle calculated at the previous calculation point, the pitch acceleration, and the time interval. 。 15. The apparatus of claim 14, comprising: Pitch acceleration is calculated from propeller thrust, propeller thrust line height, aircraft drag, gravity, distance from center of gravity to main takeoff touchdown point, aerodynamic torque, lift, distance from aerodynamic focus to center of gravity, and pitch moment of inertia about main takeoff touchdown point. 。 16. The apparatus of claim 14, comprising: Compare the updated pitch angle value of the aircraft with the calculated pitch angle value at the previous calculation point. If the difference is less than 0.001, update the pitch angle and calculate the aircraft's taxiing performance; otherwise, return to step S02.

17. The apparatus of claim 10, wherein the takeoff performance calculation module further comprises: The cumulative taxiing distance and airspeed of the aircraft when the front takeoff is off the ground, the airspeed and cumulative taxiing distance of the aircraft when the main takeoff is off the ground, the pitch angle, airspeed and landing gear support force of the aircraft are calculated over time. If the dimensionless landing gear support force is less than 0.001, the landing gear is determined to be off the ground, and a takeoff performance evaluation is performed; otherwise, return to step S02.

18. The apparatus of claim 17, comprising: The cumulative taxiing distance of the aircraft is calculated from the aircraft's ground speed and the cumulative taxiing distance at the previous calculation point: Aircraft airspeed is calculated from aircraft acceleration and airspeed at the previous calculation point: The acceleration of an aircraft is calculated from the propeller thrust, aircraft drag, and landing gear friction. After the lead lift takes off and before the main lift takes off, the friction of the lead lift is zero, and the acceleration of the aircraft is: Store the aircraft's taxiing time, pitch angle, airspeed, and landing gear support force at every moment.

19. An electronic device comprising: One or more processors; A storage device on which one or more programs are stored; When the one or more programs are executed by the one or more processors, the one or more processors implement the method as described in any one of claims 1-9.

20. A computer-readable medium having a computer program stored thereon, wherein, When the program is executed by the processor, it implements the method as described in any one of claims 1-9.

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