Method and device for adjusting and calculating position of main landing gear

Abstract

The invention belongs to the technical field of aircraft design, and relates to a main landing gear position adjustment calculation method and device. The method comprises the following steps: S1, determining an initial landing gear position corresponding to a front gravity center position initial value and an initial iteration landing gear position corresponding to an adjusted gravity center position current value according to a position rear limit model used for ensuring that an aircraft main landing gear can be lifted; s2, calculating a front wheel lifting pitching moment coefficient according to the initial iteration undercarriage position; s3, when the front wheel lifting pitching moment coefficient is smaller than the residual safety moment coefficient, the initial iteration undercarriage position is moved forwards according to the set proportion until the new front wheel lifting pitching moment coefficient is not smaller than the residual safety moment coefficient; and S4, interpolating the position of the main landing gear when the pitching moment coefficient of lifting the front wheel is equal to the residual safety moment coefficient, and taking the position as the final position of the main landing gear. According to the method, the optimal design position of the undercarriage can be accurately calculated.

Description

Technical Field

[0001] This application belongs to the field of aircraft design technology, and specifically relates to a method and device for calculating the position adjustment of the main landing gear. Background Technology

[0002] An aircraft's forward center of gravity exceeding its design value will result in insufficient pitch control performance, impacting flight safety. During takeoff, the aircraft's weight is at its maximum, and its center of gravity is also furthest forward. Raising the nose wheel during takeoff is a key constraint for evaluating aircraft handling performance. Compared to adjusting wing position and horizontal stabilizer area, adjusting the main landing gear position has the least impact on the aircraft's aerodynamic characteristics, yet the effect is very significant. The forward center of gravity position is continuously updated as the design progresses; to ensure good aircraft handling, the main landing gear position must also be adjusted accordingly. Adjusting the main landing gear position causes changes in the aircraft's center of gravity and takeoff / landing pitch control moments; accurately calculating the main landing gear position is a crucial technical problem that needs to be solved to improve aircraft pitch control performance. Summary of the Invention

[0003] To address the aforementioned issues, this application provides a method and apparatus for calculating the main landing gear position adjustment. It establishes a main landing gear position calculation model and a nose wheel pitching moment calculation model, and presents an algorithm and calculation process for accurately calculating the rear limit of the wing position. The calculation method can solve the pitch control problem caused by the aircraft's front center of gravity exceeding the design value, and is applicable to the optimized design of the main landing gear position for tricycle landing gear aircraft.

[0004] The first aspect of this application provides a method for calculating the position adjustment of the main landing gear, mainly including:

[0005] Step S1: Based on the positional constraint model used to ensure that the main landing gear of the aircraft can be lifted, determine the initial landing gear position corresponding to the initial value of the front center of gravity position, and the initial iterative landing gear position corresponding to the current value of the adjusted center of gravity position.

[0006] Step S2: Calculate the pitching moment coefficient of the nose wheel based on the initial iterative landing gear position;

[0007] Step S3: When the pitching moment coefficient of the front wheel is less than the remaining safety moment coefficient, the initial iterative landing gear position is moved forward by a set ratio until the new pitching moment coefficient of the front wheel is not less than the remaining safety moment coefficient.

[0008] Step S4: Based on the pitching moment coefficient of the front wheel when it is not less than the remaining safety moment coefficient and the pitching moment coefficient of the front wheel in the previous iteration, interpolate the main landing gear position when the pitching moment coefficient of the front wheel is equal to the remaining safety moment coefficient, and use this as the final main landing gear position.

[0009] Preferably, in step S1, the landing gear position is calculated using the following formula:

[0010] ;

[0011] in, This is 95% of the maximum pitch control moment coefficient that the horizontal stabilizer can provide;

[0012] ;

[0013] ;

[0014] in, The mean aerodynamic chord of the wing. This represents the average lift coefficient generated per unit deflection angle of the horizontal stabilizer. The tail lever arm length of the horizontal tail. The pitching moment coefficient generated by takeoff thrust. The pitching moment coefficient is the force generated by tire friction. The pitch moment coefficient is the pitch angular velocity generated at the zero-load point of the front wheels. This is the maximum downward angle of the tail. The downswing angle is the point where the front wheel of the horizontal stabilizer lifts up; a, b, and c are adjustment parameters.

[0015] ;

[0016] ;

[0017] ;

[0018] in, The maximum lift coefficient for the aircraft's takeoff configuration. The lift coefficient at the zero-load point of the aircraft's nose wheel. The aerodynamic pressure center position for a tailless configuration. This is the aircraft's main landing gear.

[0019] Preferably, each pitch moment coefficient is determined by the following formula:

[0020] ;

[0021] in, To increase the engine thrust at the point where the front wheels reach their speed point, For the number of engines, The height of the engine thrust line from the center of gravity. The velocity pressure required to lift the nose wheel during takeoff is S, where S is the wing reference area.

[0022] ;

[0023] Where W is the takeoff weight. The coefficient of friction of the tire. The height of the aircraft's center of gravity above the ground;

[0024] ;

[0025] in, This is the damped aerodynamic derivative of the aircraft's pitch rate. The pitch rate of the aircraft at the point of zero load on the nose wheel. To increase the speed of the front wheels.

[0026] Preferably, the takeoff nose wheel lift velocity pressure is calculated using the following formula:

[0027] ;

[0028] Front wheel lift speed The value is the stall speed of the takeoff configuration. .

[0029] Preferably, in step S2, the front wheel pitching moment coefficient is calculated using the following formula. :

[0030] ;

[0031] in, The pitch control moment coefficient available for the horizontal stabilizer after the main landing gear position is adjusted. To adjust the pitching moment coefficient generated by the lift, To adjust the pitching moment coefficient caused by gravity;

[0032] ;

[0033] ;

[0034] ;

[0035] in, Adjustment amount for main landing gear position The adjusted position of the main landing gear. This is the adjusted position of the front center of gravity.

[0036] Preferably, the adjusted front center of gravity position Calculated using the following formula:

[0037] ;

[0038] ;

[0039] ;

[0040] in, and These are the absolute weight and relative weight of the main landing gear, respectively. This represents the change in the position of the center of gravity. This is the position of the previous centroid during the last iteration.

[0041] Preferably, in step S3, the remaining safety torque coefficient is set to 0.003.

[0042] Preferably, in step S3, the ratio is set to 0.002.

[0043] A second aspect of this application provides a main landing gear position adjustment calculation device, mainly comprising:

[0044] The landing gear position calculation module is used to determine the initial landing gear position corresponding to the initial value of the front center of gravity position, and the initial iterative landing gear position corresponding to the current value of the adjusted center of gravity position, based on the position limit model used to ensure that the main landing gear of the aircraft can be lifted.

[0045] The nose wheel pitching moment coefficient calculation module is used to calculate the nose wheel pitching moment coefficient based on the initial iterative landing gear position.

[0046] The landing gear position adjustment module is used to move the initial iterative landing gear position forward by a set ratio when the pitching moment coefficient of the nose wheel is less than the remaining safety moment coefficient, until the new pitching moment coefficient of the nose wheel is not less than the remaining safety moment coefficient.

[0047] The main landing gear position interpolation calculation module is used to interpolate the main landing gear position when the pitching moment coefficient of the front wheel is equal to the remaining safety moment coefficient, based on the pitching moment coefficient of the front wheel when it is not less than the remaining safety moment coefficient and the pitching moment coefficient of the front wheel in the previous iteration, as the final main landing gear position.

[0048] Preferably, in the landing gear position calculation module, the landing gear position is calculated using the following formula:

[0049] ;

[0050] in, This is 95% of the maximum pitch control moment coefficient that the horizontal stabilizer can provide;

[0051] ;

[0052] ;

[0053] in, The mean aerodynamic chord of the wing. This represents the average lift coefficient generated per unit deflection angle of the horizontal stabilizer. The tail lever arm length of the horizontal tail. The pitching moment coefficient generated by takeoff thrust. The pitching moment coefficient is the force generated by tire friction. The pitch moment coefficient is the pitch angular velocity generated at the zero-load point of the front wheels. This is the maximum downward angle of the tail. The downswing angle is the point where the front wheel of the horizontal stabilizer lifts up; a, b, and c are adjustment parameters.

[0054] ;

[0055] ;

[0056] ;

[0057] in, The maximum lift coefficient for the aircraft's takeoff configuration. The lift coefficient at the zero-load point of the aircraft's nose wheel. The aerodynamic pressure center position for a tailless configuration. This is the aircraft's main landing gear.

[0058] Preferably, each pitch moment coefficient is determined by the following formula:

[0059] ;

[0060] in, To increase the engine thrust at the point where the front wheels reach their speed point, For the number of engines, The height of the engine thrust line from the center of gravity. The velocity pressure required to lift the nose wheel during takeoff is S, where S is the wing reference area.

[0061] ;

[0062] Where W is the takeoff weight. The coefficient of friction of the tire. The height of the aircraft's center of gravity above the ground;

[0063] ;

[0064] in, This is the damped aerodynamic derivative of the aircraft's pitch rate. The pitch rate of the aircraft at the point of zero load on the nose wheel. To increase the speed of the front wheels.

[0065] Preferably, the takeoff nose wheel lift velocity pressure is calculated using the following formula:

[0066] ;

[0067] Front wheel lift speed The value is the stall speed of the takeoff configuration. .

[0068] Preferably, in the front wheel pitching moment coefficient calculation module, the front wheel pitching moment coefficient is calculated using the following formula. :

[0069] ;

[0070] in, The pitch control moment coefficient available for the horizontal stabilizer after the main landing gear position is adjusted. To adjust the pitching moment coefficient generated by the lift, To adjust the pitching moment coefficient caused by gravity;

[0071] ;

[0072] ;

[0073] ;

[0074] in, Adjustment amount for main landing gear position The adjusted position of the main landing gear. This is the adjusted position of the front center of gravity.

[0075] Preferably, the adjusted front center of gravity position Calculated using the following formula:

[0076] ;

[0077] ;

[0078] ;

[0079] in, and These are the absolute weight and relative weight of the main landing gear, respectively. This represents the change in the position of the center of gravity. This is the position of the previous centroid during the last iteration.

[0080] Preferably, the remaining safety torque coefficient in the landing gear position adjustment module is set to 0.003.

[0081] Preferably, the landing gear position adjustment module is set to a ratio of 0.002.

[0082] A third aspect of this application provides a computer device including a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the main landing gear position adjustment calculation method as described above.

[0083] A fourth aspect of this application provides a readable storage medium storing a computer program that, when executed by a processor, implements the main landing gear position adjustment calculation method described above.

[0084] This application can accurately calculate the optimal design position of the landing gear. Attached Figure Description

[0085] Figure 1 This is a flowchart of a preferred embodiment of the main landing gear position adjustment calculation method of this application.

[0086] Figure 2 This is a schematic diagram of the structure of a computer device suitable for implementing the embodiments of this application. Detailed Implementation

[0087] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0088] The first aspect of this application provides a method for calculating the position adjustment of the main landing gear, such as... Figure 1 As shown, it mainly includes:

[0089] Step S1: Based on the positional constraint model used to ensure that the main landing gear of the aircraft can be lifted, determine the initial landing gear position corresponding to the initial value of the front center of gravity position, and the initial iterative landing gear position corresponding to the current value of the adjusted center of gravity position.

[0090] Step S2: Calculate the pitching moment coefficient of the nose wheel based on the initial iterative landing gear position;

[0091] Step S3: When the pitching moment coefficient of the front wheel is less than the remaining safety moment coefficient, the initial iterative landing gear position is moved forward by a set ratio until the new pitching moment coefficient of the front wheel is not less than the remaining safety moment coefficient.

[0092] Step S4: Based on the pitching moment coefficient of the front wheel when it is not less than the remaining safety moment coefficient and the pitching moment coefficient of the front wheel in the previous iteration, interpolate the main landing gear position when the pitching moment coefficient of the front wheel is equal to the remaining safety moment coefficient, and use this as the final main landing gear position.

[0093] The purpose of this invention is to address the problem of insufficient takeoff pitch control performance caused by the nose center of gravity exceeding the design value, and to provide technical support for optimizing the main landing gear position. This application analyzes the influence of the horizontal stabilizer's available pitch control capability, lift, gravity, engine thrust, tire friction, pitch rate, the aerodynamic pressure center position in a tailless configuration, and the main landing gear position on the nose wheel pitch moment. It establishes a calculation model for the rear limit of the main landing gear position, a calculation model for the change in the center of gravity and pitch moment coefficient caused by main landing gear position adjustment, a calculation model for the pitch moment generated by lift, gravity, engine thrust, tire friction, and pitch rate, and a calculation method for accurately solving the main landing gear position adjustment and the aircraft's center of gravity. To eliminate the influence of speed on pitch control performance and ensure controllability, based on design standards, the nose wheel pitch speed in the model is taken as the stall speed of the aircraft's takeoff configuration.

[0094] In this application, the x-axis coordinate is defined as follows: the origin is the leading edge of the mean aerodynamic chord of the aircraft wing, the direction is the same as the fuselage axis, and the direction backward is positive. The ratio of the aircraft's center of gravity x-axis coordinate to the mean aerodynamic chord is called the center of gravity x-axis position. The x-axis position of the aerodynamic pressure center of gravity for a tailless aircraft. This is the rear limit of the aircraft's main landing gear position along the x-axis. When the main landing gear position is greater than this value, the aircraft will be unable to lift the nose wheel.

[0095] Based on this, in step S1, the landing gear position is calculated.

[0096] In some alternative implementations, in step S1, the landing gear position is calculated using the following formula:

[0097] ;

[0098] in, This is 95% of the maximum pitch control moment coefficient that the horizontal stabilizer can provide;

[0099] ;

[0100] ;

[0101] in, The mean aerodynamic chord of the wing. This represents the average lift coefficient generated per unit deflection angle of the horizontal stabilizer. The tail lever arm length of the horizontal tail. The pitching moment coefficient generated by takeoff thrust. The pitching moment coefficient is the force generated by tire friction. The pitch moment coefficient is the pitch angular velocity generated at the zero-load point of the front wheels. This is the maximum downward angle of the tail. The downswing angle is the point where the front wheel of the horizontal stabilizer lifts up; a, b, and c are adjustment parameters.

[0102] ;

[0103] ;

[0104] ;

[0105] in, The maximum lift coefficient for the aircraft's takeoff configuration. The lift coefficient at the zero-load point of the aircraft's nose wheel. The aerodynamic pressure center position for a tailless configuration. This is the aircraft's main landing gear.

[0106] In some alternative implementations, each pitch moment coefficient is determined by the following formula:

[0107] ;

[0108] in, To increase the engine thrust at the point where the front wheels reach their speed point, For the number of engines, The height of the engine thrust line from the center of gravity. The velocity pressure required to lift the nose wheel during takeoff is S, where S is the wing reference area.

[0109] ;

[0110] Where W is the takeoff weight. The coefficient of friction of the tire. The height of the aircraft's center of gravity above the ground;

[0111] ;

[0112] in, This is the damped aerodynamic derivative of the aircraft's pitch rate. The pitch rate of the aircraft at the point of zero load on the nose wheel. To increase the speed of the front wheels.

[0113] In some alternative implementations, the velocity pressure of the nose wheel during takeoff is calculated using the following formula:

[0114] ;

[0115] Front wheel lift speed The value is the stall speed of the takeoff configuration. .

[0116] Next, in step S2, the pitching moment coefficient of the front wheel is calculated.

[0117] In some alternative implementations, in step S2, the front wheel pitching moment coefficient is calculated using the following formula. :

[0118] ;

[0119] in, The pitch control moment coefficient available for the horizontal stabilizer after the main landing gear position is adjusted. To adjust the pitching moment coefficient generated by the lift, To adjust the pitching moment coefficient caused by gravity;

[0120] ;

[0121] ;

[0122] ;

[0123] in, Adjustment amount for main landing gear position The adjusted position of the main landing gear. This is the adjusted position of the front center of gravity.

[0124] In some alternative implementations, the adjusted front center of gravity position Calculated using the following formula:

[0125] ;

[0126] ;

[0127] ;

[0128] in, and These are the absolute weight and relative weight of the main landing gear, respectively. This represents the change in the position of the center of gravity. This is the position of the previous centroid during the last iteration.

[0129] Then, in step S3, considering the change in the center of gravity position caused by the movement of the main landing gear and the change in the available pitch control torque of the horizontal stabilizer, the landing gear position in the previous iteration is... Based on this, increase the set percentage of movement and recalculate the pitching moment coefficient of the aircraft lifting the nose wheel in this state. until it exceeds the remaining safety torque coefficient.

[0130] In some alternative implementations, in step S3, the remaining safety torque coefficient is set to 0.003.

[0131] In some alternative implementations, in step S3, the ratio is set to 0.002.

[0132] The aircraft in the simulation is a high-wing transport aircraft with four turbofan engines mounted under the wings. The wing reference area is 300 m². 2 The mean aerodynamic chord length (Ca) is 6.4m. The engine thrust axis is 0.448m above the center of gravity, and the aircraft's center of gravity is 1.92m above the ground. Initial design: the nose center of gravity was 0.23Ca, and the main landing gear was 0.57Ca. The current nose center of gravity is 0.2Ca. The forward shift of the center of gravity results in insufficient takeoff nose wheel control torque, necessitating a forward shift of the main landing gear.

[0133] Calculated conditions: takeoff weight 180t, engine thrust 120KN.

[0134] Since the maximum pitch control coefficient available for the horizontal stabilizer is 95%, theoretically, as long as the pitch moment coefficient when the nose wheel is raised is positive, the remaining safety moment coefficient in this application is taken as 0.003. After five rounds of cyclic calculations, as shown in Table 1, the result of the fourth calculation is 0.00324, which is greater than 0.003. Therefore, the results of the third and fourth calculations are interpolated to obtain that when the pitch moment coefficient when the nose wheel is raised is 0.003, the main landing gear position moves forward by 0.0517Ca, the main landing gear position is adjusted to 0.522Ca, and the front center of gravity position is 0.1933Ca.

[0135] Table 5. Data from the solution of the rear limit values ​​for the main landing gear position.

[0136]

[0137] A second aspect of this application provides a main landing gear position adjustment calculation device corresponding to the above method, mainly comprising:

[0138] The landing gear position calculation module is used to determine the initial landing gear position corresponding to the initial value of the front center of gravity position, and the initial iterative landing gear position corresponding to the current value of the adjusted center of gravity position, based on the position limit model used to ensure that the main landing gear of the aircraft can be lifted.

[0139] The nose wheel pitching moment coefficient calculation module is used to calculate the nose wheel pitching moment coefficient based on the initial iterative landing gear position.

[0140] The landing gear position adjustment module is used to move the initial iterative landing gear position forward by a set ratio when the pitching moment coefficient of the nose wheel is less than the remaining safety moment coefficient, until the new pitching moment coefficient of the nose wheel is not less than the remaining safety moment coefficient.

[0141] The main landing gear position interpolation calculation module is used to interpolate the main landing gear position when the pitching moment coefficient of the front wheel is equal to the remaining safety moment coefficient, based on the pitching moment coefficient of the front wheel when it is not less than the remaining safety moment coefficient and the pitching moment coefficient of the front wheel in the previous iteration, as the final main landing gear position.

[0142] In some alternative implementations, the landing gear position calculation module calculates the landing gear position using the following formula:

[0143] ;

[0144] in, This is 95% of the maximum pitch control moment coefficient that the horizontal stabilizer can provide;

[0145] ;

[0146] ;

[0147] in, The mean aerodynamic chord of the wing. This represents the average lift coefficient generated per unit deflection angle of the horizontal stabilizer. The tail lever arm length of the horizontal tail. The pitching moment coefficient generated by takeoff thrust. The pitching moment coefficient is the force generated by tire friction. The pitch moment coefficient is the pitch angular velocity generated at the zero-load point of the front wheels. This is the maximum downward angle of the tail. The downswing angle is the point where the front wheel of the horizontal stabilizer lifts up; a, b, and c are adjustment parameters.

[0148] ;

[0149] ;

[0150] ;

[0151] in, The maximum lift coefficient for the aircraft's takeoff configuration. The lift coefficient at the zero-load point of the aircraft's nose wheel. The aerodynamic pressure center position for a tailless configuration. This is the aircraft's main landing gear.

[0152] In some alternative implementations, each pitch moment coefficient is determined by the following formula:

[0153] ;

[0154] in, To increase the engine thrust at the point where the front wheels reach their speed point, For the number of engines, The height of the engine thrust line from the center of gravity. The velocity pressure required to lift the nose wheel during takeoff is S, where S is the wing reference area.

[0155] ;

[0156] Where W is the takeoff weight. The coefficient of friction of the tire. The height of the aircraft's center of gravity above the ground;

[0157] ;

[0158] in, This is the damped aerodynamic derivative of the aircraft's pitch rate. The pitch rate of the aircraft at the point of zero load on the nose wheel. To increase the speed of the front wheels.

[0159] In some alternative implementations, the velocity pressure of the nose wheel during takeoff is calculated using the following formula:

[0160] ;

[0161] Front wheel lift speed The value is the stall speed of the takeoff configuration. .

[0162] In some optional embodiments, the front wheel pitching moment coefficient calculation module calculates the front wheel pitching moment coefficient using the following formula. :

[0163] ;

[0164] in, The pitch control moment coefficient available for the horizontal stabilizer after the main landing gear position is adjusted. To adjust the pitching moment coefficient generated by the lift, To adjust the pitching moment coefficient caused by gravity;

[0165] ;

[0166] ;

[0167] ;

[0168] in, Adjustment amount for main landing gear position The adjusted position of the main landing gear. This is the adjusted position of the front center of gravity.

[0169] In some alternative implementations, the adjusted front center of gravity position Calculated using the following formula:

[0170] ;

[0171] ;

[0172] ;

[0173] in, and These are the absolute weight and relative weight of the main landing gear, respectively. This represents the change in the position of the center of gravity. This is the position of the previous centroid during the last iteration.

[0174] In some alternative implementations, the remaining safety torque coefficient in the landing gear position adjustment module is set to 0.003.

[0175] In some alternative implementations, the landing gear position adjustment module is set to a ratio of 0.002.

[0176] In a third aspect of this application, a computer device is provided, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the main landing gear position adjustment calculation method as described above.

[0177] In a fourth aspect, this application provides a readable storage medium storing a computer program that, when executed by a processor, implements the main landing gear position adjustment calculation method described above. This computer-readable storage medium may be included in the apparatus described in the above embodiments; or it may exist independently and not incorporated into the apparatus. The aforementioned computer-readable storage medium carries one or more programs that, when executed by the apparatus, process data according to the method described above.

[0178] The following is for reference. Figure 2It shows a schematic diagram of the structure of a computer device 400 suitable for implementing the embodiments of this application. Figure 2 The computer device shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments described in this application.

[0179] like Figure 2 As shown, the computer device 400 includes a central processing unit (CPU) 401, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 402 or a program loaded from a storage section 408 into a random access memory (RAM) 403. The RAM 403 also stores various programs and data required for the operation of the device 400. The CPU 401, ROM 402, and RAM 403 are interconnected via a bus 404. An input / output (I / O) interface 405 is also connected to the bus 404.

[0180] The following components are connected to I / O interface 405: an input section 406 including a keyboard, mouse, etc.; an output section 407 including a cathode ray tube (CRT), liquid crystal display (LCD), etc., and speakers, etc.; a storage section 408 including a hard disk, etc.; and a communication section 409 including a network interface card such as a LAN card, modem, etc. The communication section 409 performs communication processing via a network such as the Internet. A drive 410 is also connected to I / O interface 405 as needed. A removable medium 411, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed on drive 410 as needed so that computer programs read from it can be installed into storage section 408 as needed.

[0181] Specifically, according to embodiments of this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication section 409, and / or installed from removable medium 411. When the computer program is executed by central processing unit (CPU) 401, it performs the functions defined in the methods of this application. It should be noted that the computer storage medium of this application can be a computer-readable signal medium or a computer-readable storage medium, or any combination thereof. A computer-readable storage medium can be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this application, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in connection with an instruction execution system, apparatus, or device. In this application, a computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on a computer-readable medium can be transmitted using any suitable medium, including but not limited to: wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0182] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0183] The modules or units described in the embodiments of this application can be implemented in software or hardware. The described modules or units can also be located in a processor, and the names of these modules or units do not necessarily constitute a limitation on the module or unit itself.

[0184] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for calculating the position adjustment of the main landing gear, characterized in that, include: Step S1: Based on the positional constraint model used to ensure that the main landing gear of the aircraft can be lifted, determine the initial landing gear position corresponding to the initial value of the front center of gravity position, and the initial iterative landing gear position corresponding to the current value of the adjusted center of gravity position. Step S2: Calculate the pitching moment coefficient of the nose wheel based on the initial iterative landing gear position; Step S3: When the pitching moment coefficient of the front wheel is less than the remaining safety moment coefficient, the initial iterative landing gear position is moved forward by a set ratio until the new pitching moment coefficient of the front wheel is not less than the remaining safety moment coefficient. Step S4: Based on the pitching moment coefficient of the front wheel when it is not less than the remaining safety moment coefficient and the pitching moment coefficient of the front wheel in the previous iteration, interpolate the main landing gear position when the pitching moment coefficient of the front wheel is equal to the remaining safety moment coefficient, and use this as the final main landing gear position.

2. The main landing gear position adjustment calculation method as described in claim 1, characterized in that, In step S1, the landing gear position is calculated using the following formula: ； in, This is 95% of the maximum pitch control moment coefficient that the horizontal stabilizer can provide; ； ； in, The mean aerodynamic chord of the wing. This represents the average lift coefficient generated per unit deflection angle of the horizontal stabilizer. The tail lever arm length of the horizontal tail. The pitching moment coefficient generated by takeoff thrust. The pitching moment coefficient is the force generated by tire friction. The pitch moment coefficient is the pitch angular velocity generated at the zero-load point of the front wheels. This is the maximum downward angle of the tail. The downswing angle is the point where the front wheel of the horizontal stabilizer lifts up; a, b, and c are adjustment parameters. ； ； ； in, The maximum lift coefficient for the aircraft's takeoff configuration. The lift coefficient at the zero-load point of the aircraft's nose wheel. The aerodynamic pressure center position for a tailless configuration. This is the aircraft's main landing gear.

3. The main landing gear position adjustment calculation method as described in claim 2, characterized in that, Each pitch moment coefficient is determined by the following formula: ； in, To increase the engine thrust at the point where the front wheels reach their speed point, For the number of engines, The height of the engine thrust line from the center of gravity. The velocity pressure required to lift the nose wheel during takeoff is S, where S is the wing reference area. ； Where W is the takeoff weight. The coefficient of friction of the tire. The height of the aircraft's center of gravity above the ground; ； in, This is the damped aerodynamic derivative of the aircraft's pitch rate. The pitch rate of the aircraft at the point of zero load on the nose wheel. To increase the speed of the front wheels.

4. The main landing gear position adjustment calculation method as described in claim 3, characterized in that, The takeoff nose wheel lift velocity pressure is calculated using the following formula: ； Front wheel lift speed The value is the stall speed of the takeoff configuration. .

5. The main landing gear position adjustment calculation method as described in claim 3, characterized in that, In step S2, the pitching moment coefficient of the front wheel is calculated using the following formula. : ； in, The pitch control moment coefficient available for the horizontal stabilizer after the main landing gear position is adjusted. To adjust the pitching moment coefficient generated by the lift, To adjust the pitching moment coefficient caused by gravity; ； ； ； in, Adjustment amount for main landing gear position The adjusted position of the main landing gear. This is the adjusted position of the front center of gravity.

6. The main landing gear position adjustment calculation method as described in claim 5, characterized in that, Adjusted front center of gravity position Calculated using the following formula: ； ； ； in, and These are the absolute weight and relative weight of the main landing gear, respectively. This represents the change in the position of the center of gravity. This is the position of the previous centroid during the last iteration.

7. The main landing gear position adjustment calculation method as described in claim 1, characterized in that, In step S3, the remaining safety torque coefficient is set to 0.

003.

8. The main landing gear position adjustment calculation method as described in claim 1, characterized in that, In step S3, the ratio is set to 0.

002.

9. A main landing gear position adjustment calculation device, characterized in that, include: The landing gear position calculation module is used to determine the initial landing gear position corresponding to the initial value of the front center of gravity position, and the initial iterative landing gear position corresponding to the current value of the adjusted center of gravity position, based on the position limit model used to ensure that the main landing gear of the aircraft can be lifted. The nose wheel pitching moment coefficient calculation module is used to calculate the nose wheel pitching moment coefficient based on the initial iterative landing gear position. The landing gear position adjustment module is used to move the initial iterative landing gear position forward by a set ratio when the pitching moment coefficient of the nose wheel is less than the remaining safety moment coefficient, until the new pitching moment coefficient of the nose wheel is not less than the remaining safety moment coefficient. The main landing gear position interpolation calculation module is used to interpolate the main landing gear position when the pitching moment coefficient of the front wheel is equal to the remaining safety moment coefficient, based on the pitching moment coefficient of the front wheel when it is not less than the remaining safety moment coefficient and the pitching moment coefficient of the front wheel in the previous iteration, as the final main landing gear position.

10. The main landing gear position adjustment calculation device as described in claim 9, characterized in that, In the landing gear position calculation module, the landing gear position is calculated using the following formula: ； in, This is 95% of the maximum pitch control moment coefficient that the horizontal stabilizer can provide; ； ； in, The mean aerodynamic chord of the wing. This represents the average lift coefficient generated per unit deflection angle of the horizontal stabilizer. The tail lever arm length of the horizontal tail. The pitching moment coefficient generated by takeoff thrust. The pitching moment coefficient is the force generated by tire friction. The pitch moment coefficient is the pitch angular velocity generated at the zero-load point of the front wheels. This is the maximum downward angle of the tail. The downswing angle is the point where the front wheel of the horizontal stabilizer lifts up; a, b, and c are adjustment parameters. ； ； ； in, The maximum lift coefficient for the aircraft's takeoff configuration. The lift coefficient at the zero-load point of the aircraft's nose wheel. The aerodynamic pressure center position for a tailless configuration. This is the aircraft's main landing gear.

11. The main landing gear position adjustment calculation device as described in claim 10, characterized in that, Each pitch moment coefficient is determined by the following formula: ； in, To increase the engine thrust at the point where the front wheels reach their speed point, For the number of engines, The height of the engine thrust line from the center of gravity. The velocity pressure required to lift the nose wheel during takeoff is S, where S is the wing reference area. ； Where W is the takeoff weight. The coefficient of friction of the tire. The height of the aircraft's center of gravity above the ground; ； in, This is the damped aerodynamic derivative of the aircraft's pitch rate. The pitch rate of the aircraft at the point of zero load on the nose wheel. To increase the speed of the front wheels.

12. The main landing gear position adjustment calculation device as described in claim 11, characterized in that, The takeoff nose wheel lift velocity pressure is calculated using the following formula: ； Front wheel lift speed The value is the stall speed of the takeoff configuration. .

13. The main landing gear position adjustment calculation device as described in claim 11, characterized in that, In the front wheel pitch moment coefficient calculation module, the front wheel pitch moment coefficient is calculated using the following formula. : ； in, The pitch control moment coefficient available for the horizontal stabilizer after the main landing gear position is adjusted. To adjust the pitching moment coefficient generated by the lift, To adjust the pitching moment coefficient caused by gravity; ； ； ； in, Adjustment amount for main landing gear position The adjusted position of the main landing gear. This is the adjusted position of the front center of gravity.

14. The main landing gear position adjustment calculation device as described in claim 13, characterized in that, Adjusted front center of gravity position Calculated using the following formula: ； ； ； in, and These are the absolute weight and relative weight of the main landing gear, respectively. This represents the change in the position of the center of gravity. This is the position of the previous centroid during the last iteration.

15. The main landing gear position adjustment calculation device as described in claim 9, characterized in that, In the landing gear position adjustment module, the remaining safety torque coefficient is set to 0.

003.

16. The main landing gear position adjustment calculation device as described in claim 9, characterized in that, In the landing gear position adjustment module, the set ratio is 0.

002.

17. A computer device, characterized in that, It includes a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the main landing gear position adjustment calculation method as described in any one of claims 1-8.

18. A readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it is used to implement the main landing gear position adjustment calculation method as described in any one of claims 1-8.

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