Method and system for determining maximum load of wheel starting chock before test run of airplane

Abstract

The invention belongs to the technical field of aircraft test run, and particularly relates to a method and system for determining the maximum load of a wheel starting chock before aircraft test run, and the method is characterized in that the method comprises the steps: determining the vertical load of a front main landing gear: determining the vertical load of the front main landing gear; a step of determining a front wheel-starting block load of balancing course force: calculating the front wheel-starting block load according to an aircraft course force balance equation; a step of determining a front wheel-set gear load before balancing the turning moment: calculating the front wheel-set gear load according to an aircraft turning moment balance equation; and a step of determining the maximum load of the front wheel chock: determining the maximum load of the front wheel chock based on the load of the front wheel chock for balancing the course force and the load of the front wheel chock for balancing the turning moment.

Description

Technical Field

[0001] The present application belongs to the technical field of aircraft test runs, and in particular relates to a method and system for determining the maximum load of wheel chocks before aircraft test runs. Background Art

[0002] During the aircraft test run, the maximum load transmitted to the wheel chock by the nose landing gear is an important parameter that needs to be considered when designing the wheel chock before the test run.

[0003] Currently, the maximum load of the front chocks before aircraft test runs is mostly determined by drawing on engineering experience. Since many factors such as engine test power, aircraft weight and center of gravity, test fuel quantity, atmospheric temperature, ground wind speed and direction all have an impact on the aircraft test force analysis, if the maximum load of the front chocks before aircraft test runs is determined only based on engineering experience and the front chocks are designed, it is easy for the maximum resistance of the designed front chocks to be too small or too large.

[0004] If the front wheel chock is designed for too little resistance, the maximum resistance that the front wheel chock can provide during the aircraft test run will be too small, and it will not be able to balance the aircraft's forward or turning movement tendency, which will cause the aircraft to slide and affect the safety of the aircraft test run. If the front wheel chock is designed for too much resistance, although it can provide sufficient resistance, it will consume higher design and processing costs.

[0005] This application is proposed in view of the above-mentioned technical defects. Summary of the Invention

[0006] The purpose of the present application is to provide a method and system for determining the maximum load of wheel blocks before aircraft test, so as to overcome or alleviate at least one aspect of the known technical defects.

[0007] The technical solution of this application is:

[0008] On the one hand, a method for determining the maximum load of wheel chocks before aircraft test is provided, comprising:

[0009] The steps for determining the vertical load of the front main landing gear are as follows: determining the vertical load of the front main landing gear;

[0010] Steps for determining the nose wheel chock load to balance the heading force: Calculate the nose wheel chock load based on the aircraft heading force balance equation;

[0011] To determine the nose chock load for balanced turning moment: Calculate the nose chock load based on the aircraft turning moment balance equation;

[0012] The maximum load of the front wheel chock is determined by: determining the maximum load of the front wheel chock based on the front wheel chock load of the balanced heading force and the front wheel chock load of the balanced turning moment.

[0013] According to at least one embodiment of the present application, in the above-mentioned method for determining the maximum load on the front wheel block during aircraft test, the step of determining the vertical load on the front main landing gear is specifically as follows:

[0014] F nz +F mz +F my +F fz -G=0;

[0015]

[0016] F mz +△F=F my -△F;

[0017] in,

[0018] F nz is the vertical load of the front landing gear; F mz is the vertical load of the left main landing gear; F my is the vertical load of the right main landing gear;

[0019] F fx is the wind load heading force component; F fz is the vertical force component of wind load; M fy is the moment component of wind load around the y-axis; G is the aircraft gravity; F fz is the vertical component of wind load; P l P is the test thrust percentage of the left engine of the aircraft; r F is the test thrust percentage of the right engine of the aircraft; t is the full power thrust value of a single engine; α is the angle between the engine thrust axis and the horizontal plane; μ is the friction coefficient between the tire and the ground; R z Main landing gear tire radius; D nz 、D fx 、D fz 、D g 、D tz 、D tx They are the vertical forces F of the front landing gear nz , wind load heading force component F fx , vertical force component of wind load F fz , aircraft gravity G, and left and right engine thrust P l F t 、P r F t Moments of vertical and yaw force components to the main landing gear axles;

[0020] △F is the unbalanced moment △M of the aircraft around the x-axis x , vertical load distributed to the left and right main landing gear.

[0021] According to at least one embodiment of the present application, in the above-mentioned method for determining the maximum load on the front wheel block during aircraft test, in the step of determining the vertical load on the front main landing gear:

[0022]

[0023] in,

[0024] y zl 、y yl is the value of the coordinate of the center point of the left and right main landing gear axles in the y direction.

[0025] According to at least one embodiment of the present application, in the above-mentioned method for determining the maximum load on the front wheel block during aircraft test, in the step of determining the vertical load on the front main landing gear:

[0026] △M x =-G·y g +F fz ·y f -F fy ·z f +M fx +(P l -P r )·F t ·sinα·y zf ;

[0027] in,

[0028] y g 、y f 、y zf are the coordinates of the aircraft's center of gravity, the wind load action point, and the left engine's thrust action point in the y direction;

[0029] z f is the value of the coordinate of the wind load action point in the z direction;

[0030] F fy is the lateral force component of wind load;

[0031] M fx is the heading moment component of the wind load.

[0032] According to at least one embodiment of the present application, in the above-mentioned method for determining the maximum load on the starting chocks before aircraft test run, the step of determining the starting chock load before balancing the yaw force is specifically as follows:

[0033] F ld1 +f c1 +f c2 -(P l +P r )·F t ·cosα+F fx =0;

[0034] in,

[0035] F ld1 To balance the heading force, the front wheel chock load;

[0036] f c1 、f c2 The friction between the left and right main landing gear wheel brake tires and the ground;

[0037] F fx is the heading force component of the wind load.

[0038] According to at least one embodiment of the present application, in the above-mentioned method for determining the maximum load on the starting chocks before aircraft test, in the step of determining the starting chock load before balancing the yaw force:

[0039] f c1 =μ·F mz ;

[0040] f c2 =μ·F my .

[0041] According to at least one embodiment of the present application, in the above-mentioned method for determining the maximum chock load before aircraft test, the step of determining the chock load before balancing the turning moment is specifically as follows:

[0042]

[0043] in,

[0044] d is the distance from the aircraft's symmetry plane to the right of the aircraft, where the aircraft's rotation axis is perpendicular to the ground;

[0045] y yf is the value of the coordinate of the thrust action point of the right engine in the y direction;

[0046] x zf is the value of the coordinate of the thrust action point of the left engine in the x direction;

[0047] x f 、y f The coordinates of the wind load action point in the x and y directions

[0048] F ld2 To balance the turning moment, the front wheel chock load is applied.

[0049] According to at least one embodiment of the present application, in the above-mentioned method for determining the maximum load on the starting chocks before aircraft test, in the step of determining the starting chock load before balancing the turning moment:

[0050]

[0051] y zfis the value of the coordinate of the thrust action point of the left engine in the y direction.

[0052] According to at least one embodiment of the present application, in the above-mentioned method for determining the maximum load of the front wheel block during aircraft test, the step of determining the maximum load of the front wheel block is specifically as follows:

[0053] Comparison of balanced heading force and front wheel block load F ld1 , balanced turning moment front wheel block load F ld2 If the balanced heading force is the front wheel block load F ld1 Less than the front wheel block load F of the balanced turning moment ld2 , then further determine the front wheel block load F before the balanced turning moment ld2 Is it less than 0? If so, the maximum load F of the front wheel block ld Take 0, if not, the maximum load of the front wheel block F ld Take the wheel block load F before balancing the turning moment ld2 ;

[0054] If the wheel block load F before balancing the heading force ld1 Not less than the front wheel block load F of the balanced turning moment ld2 , then we can further determine the front wheel block load F of the balanced heading force ld1 Is it less than 0? If so, the maximum load F of the front wheel block ld Take 0, if not, then the maximum load of the front wheel block F ld Take the wheel block load F before balancing the heading force ld1 .

[0055] Another aspect provides a system for determining the maximum load of wheel blocks before aircraft test, characterized by comprising:

[0056] A front main landing gear vertical load determination module, used to determine the front main landing gear vertical load;

[0057] A module for determining the front wheel chock load for balancing the heading force is used to calculate the front wheel chock load based on the aircraft heading force balance equation;

[0058] A module for determining the front wheel chock load for balanced turning moment is used to calculate the front wheel chock load based on the aircraft turning moment balance equation;

[0059] The front wheel chock maximum load determination module is used to determine the front wheel chock maximum load based on the front wheel chock load of the balanced heading force and the front wheel chock load of the balanced turning moment.

[0060] According to at least one embodiment of the present application, in the above-mentioned aircraft front start-up chock maximum load determination system, the front main landing gear vertical load determination module specifically includes:

[0061] F nz+F mz +F my +F fz -G=0;

[0062]

[0063] F mz +△F=F my -△F;

[0064] in,

[0065] F nz is the vertical load of the front landing gear; F mz is the vertical load of the left main landing gear; F my is the vertical load of the right main landing gear;

[0066] F fx is the wind load heading force component; F fz is the vertical force component of wind load; M fy is the moment component of wind load around the y-axis; G is the aircraft gravity; F fz is the vertical component of wind load; P l P is the test thrust percentage of the left engine of the aircraft; r F is the test thrust percentage of the right engine of the aircraft; t is the full power thrust value of a single engine; α is the angle between the engine thrust axis and the horizontal plane; μ is the friction coefficient between the tire and the ground; R z Main landing gear tire radius; D nz 、D fx 、D fz 、D g 、D tz 、D tx They are the vertical forces F of the front landing gear nz , wind load heading force component F fx , vertical force component of wind load F fz , aircraft gravity G, and left and right engine thrust P l F t 、P r F t Moments of vertical and yaw force components to the main landing gear axles;

[0067] △F is the unbalanced moment △M of the aircraft around the x-axis x , vertical load distributed to the left and right main landing gear.

[0068] According to at least one embodiment of the present application, in the above-mentioned aircraft front start-up chock maximum load determination system, in the front main landing gear vertical load determination module:

[0069]

[0070] in,

[0071] y zl 、y yl is the value of the coordinate of the center point of the left and right main landing gear axles in the y direction.

[0072] According to at least one embodiment of the present application, in the above-mentioned aircraft front start-up chock maximum load determination system, in the front main landing gear vertical load determination module:

[0073] △M x =-G·y g +F fz ·y f -F fy ·z f +M fx +(P l -P r )·F t ·sinα·y zf ;

[0074] in,

[0075] y g 、y f 、y zf are the coordinates of the aircraft's center of gravity, the wind load action point, and the left engine's thrust action point in the y direction;

[0076] z f is the value of the coordinate of the wind load action point in the z direction;

[0077] F fy is the lateral force component of wind load;

[0078] M fx is the heading moment component of the wind load.

[0079] According to at least one embodiment of the present application, in the above-mentioned system for determining the maximum load on the starting chocks before aircraft test, the module for determining the starting chock load before balancing the yaw force is specifically as follows:

[0080] F ld1 +f c1 +f c2 -(P l +P r )·F t ·cosα+F fx =0;

[0081] in,

[0082] F ld1 To balance the heading force, the front wheel chock load;

[0083] fc1 、f c2 The friction between the left and right main landing gear wheel brake tires and the ground;

[0084] F fx is the heading force component of the wind load.

[0085] According to at least one embodiment of the present application, in the above-mentioned system for determining the maximum load on the starting block before aircraft test, in the module for determining the starting block load before balancing the yaw force:

[0086] f c1 =μ·F mz ;

[0087] f c2 =μ·F my .

[0088] According to at least one embodiment of the present application, in the above-mentioned system for determining the maximum load on the starting chock before aircraft test, the module for determining the starting chock load before balancing the turning moment is specifically as follows:

[0089]

[0090] in,

[0091] d is the distance from the aircraft's symmetry plane to the right of the aircraft, where the aircraft's rotation axis is perpendicular to the ground;

[0092] y yf is the value of the coordinate of the thrust action point of the right engine in the y direction;

[0093] x zf is the value of the coordinate of the thrust action point of the left engine in the x direction;

[0094] x f 、y f The coordinates of the wind load action point in the x and y directions

[0095] F ld2 To balance the turning moment, the front wheel chock load is applied.

[0096] According to at least one embodiment of the present application, in the above-mentioned system for determining the maximum load on the starting block before aircraft test, in the module for determining the starting block load before balancing the turning moment:

[0097]

[0098] y zf is the value of the coordinate of the thrust action point of the left engine in the y direction;

[0099] According to at least one embodiment of the present application, in the above-mentioned aircraft front start-up chock maximum load determination system, the front start-up chock maximum load determination module specifically includes:

[0100] Comparison of balanced heading force and front wheel block load F ld1 , balanced turning moment front wheel block load F ld2 If the balanced heading force is the front wheel block load F ld1 Less than the front wheel block load F of the balanced turning moment ld2 , then further determine the front wheel block load F before the balanced turning moment ld2 Is it less than 0? If so, the maximum load F of the front wheel block ld Take 0, if not, then the maximum load of the front wheel block F ld Take the wheel block load F before balancing the turning moment ld2 ;

[0101] If the wheel block load F before balancing the heading force ld1 Not less than the front wheel block load F of the balanced turning moment ld2 , then we can further determine the front wheel block load F of the balanced heading force ld1 Is it less than 0? If so, the maximum load F of the front wheel block ld Take 0, if not, then the maximum load of the front wheel block F ld Take the wheel block load F before balancing the heading force ld1 .

[0102] This application has at least the following beneficial technical effects:

[0103] Provided are a method and system for determining the maximum load of the front chocks during an aircraft test run. Based on the unbalanced state of relative sliding between the aircraft and the ground during a test run without chocks, the method comprehensively considers and theoretically calculates the load transmitted from the landing gear to the test chocks under the action of multiple factors, and calculates and determines the maximum load of the front chocks during an aircraft test run. The method is simple and clear, has a sufficient theoretical basis, and comprehensively considers the wind load at different temperatures and wind speeds, and the load addition and reduction on the landing gear by the engine thrust. The method can efficiently and relatively accurately determine the maximum load of the front chocks during an aircraft test run, and can further effectively guide the design of the front chocks, avoiding the situation where the maximum resistance of the designed front chocks is too small or too large. BRIEF DESCRIPTION OF THE DRAWINGS

[0104] Figure 1 This is a schematic diagram of determining the main geometric parameters required for force analysis of a previous aircraft test run in the aircraft global coordinate system provided by an embodiment of the present application;

[0105] Figure 2 Schematic diagram of a method for determining the maximum load of wheel chocks before aircraft test run provided by an embodiment of the present application;

[0106] Figure 3Schematic diagram of the force analysis in the xoz plane during aircraft test run provided by an embodiment of the present application;

[0107] Figure 4 It is a schematic diagram of the force analysis in the yoz plane of the machine test run provided in an embodiment of the present application;

[0108] Figure 5 Schematic diagram of a system for determining the maximum load of wheel chocks before aircraft test runs provided in an embodiment of the present application.

[0109] In order to better illustrate this embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. In addition, the drawings are only used for illustrative purposes and should not be understood as limiting this application. DETAILED DESCRIPTION

[0110] To make the technical solution and its advantages of this application more clear, the technical solution of this application will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described here are only some of the embodiments of this application and are only used to explain this application, not to limit this application. It should be noted that for ease of description, only the parts relevant to this application are shown in the accompanying drawings, and other relevant parts can refer to the general design.

[0111] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of this application should have the usual meanings understood by those skilled in the art in the field to which this application belongs. The words indicating orientation used in the description of this application are only used to indicate relative directions or positional relationships. When the absolute position of the described object changes, its relative positional relationship may also change accordingly. The word "include" used in the description of this application means that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, but does not exclude other elements or objects.

[0112] In addition, it should be noted that, unless otherwise clearly stipulated and limited, the words "installation", "connection" and similar terms used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Technical personnel in the field can understand its specific meaning in this application according to the specific circumstances.

[0113] In practice, the aircraft test conditions mainly include the aircraft left engine test thrust percentage P l , dimensionless; aircraft right engine test thrust percentage P r , dimensionless; friction coefficient between tire and ground μ, dimensionless; test oil volume M oil, unit: kg; total mass of aircraft M, unit: kg; atmospheric temperature T, unit: ℃; wind speed V, unit: m / s; wind direction β, unit: °;

[0114] In the above conditions, the test oil volume M oil It can be used to determine the aircraft's center of gravity, avoiding unnecessary errors caused by changes in the aircraft's center of gravity due to different fuel levels. Furthermore, atmospheric temperature T, wind speed V, and wind direction β can be used to determine the maximum thrust of the engine and the magnitude of each component of the wind load.

[0115] Establish the aircraft global coordinate system, such as Figure 1 As shown, the y-axis points to the right wing tip. For the force analysis of the front three-point landing gear aircraft test, the main geometric parameters that need to be determined include the coordinates of the center of gravity of the aircraft (x g ,y g ,z g ), unit: m; front landing gear wheel tire radius R q , unit: m; main landing gear tire radius R z , unit: m; coordinates of the center point of the front landing gear axle (x ql ,y ql ,z ql ), unit: m; coordinates of the center point of the left main landing gear axle (x zl ,y zl ,z zl ), unit: m; coordinates of the center point of the right main landing gear axle (x yl ,y yl ,z yl ), unit: m; coordinates of the left engine thrust point (x zf ,y zf ,z zf ), unit: m; coordinates of the right engine thrust action point (x yf ,y yf ,z yf ), unit: m; the angle α between the thrust axis of each engine and the horizontal plane, unit: °; the coordinates of the wind load action point (x f ,y f ,z f ), unit: m. For the convenience of calculation, the heading and vertical coordinates of the left and right main landing gear axle centers can be made equal, that is, x zl =x yl , z zl =z yl , and make the heading and vertical coordinates of the left and right engine thrust points equal, that is, x zf =x yf , z zf =z yf .

[0116] Determine the necessary input parameter values ​​required for the aircraft test calculation conditions, including the single engine full power thrust value F corresponding to different temperatures T, wind speeds V, and wind directions β t And the wind load action point (x f ,y f ,z f ) in the three perpendicular directions x, y, and z fx 、F fy 、F fz and the moment component M fx 、M fy 、M fz Etc., as shown in the following table:

[0117] On the one hand, the present application provides a method for determining the maximum load of the wheel block before the aircraft test run, such as Figure 2 shown.

[0118] Steps for determining the vertical load on the front main landing gear: Determine the vertical load on the front main landing gear.

[0119] The force analysis of the aircraft test on the xoz plane and xoy plane is as follows Figure 3 and Figure 4 As shown, from the equilibrium relationship of vertical force (force in the z-axis direction):

[0120] ∑F z =0…………(1)

[0121] in,

[0122] ∑F z is the sum of the vertical forces, where the vertical force includes the front landing gear vertical force F nz , left main landing gear vertical force F mz , right main landing gear vertical force F my , aircraft gravity G and vertical component of wind load F fz , then formula (1) can be expressed as:

[0123] F nz +F mz +F my +F fz -G=0…………(2)

[0124] According to the moment balance relationship around the line connecting the center points of the left and right main landing gear axles, we can obtain:

[0125] ∑M y =0…………(3)

[0126] in,

[0127] ∑M yis the sum of the moments around the line connecting the center points of the left and right main landing gear axles, where the moments around the line connecting the center points of the left and right main landing gear axles include the vertical force F of the front landing gear. nz Moment, wind load heading force component F fx Moment, vertical force component of wind load F fz Moment, wind load moment component M around the y-axis fy , aircraft gravity G moment, and left and right engine thrust P l F t 、P r F t The vertical force and heading force component moment, then formula (2) can be expressed as:

[0128]

[0129] in,

[0130] D nz 、D fx 、D fz 、D g 、D tz 、D tx They are the vertical forces F of the front landing gear nz , wind load heading force component F fx , vertical force component of wind load F fz , aircraft gravity G, and left and right engine thrust P l F t 、P r F t The moments of the vertical force and the yaw force components to the main landing gear axle can be calculated based on the coordinates of the force application point and the coordinates of the center point of the main landing gear axle.

[0131] Calculate the unbalanced moment △M of the aircraft around the x-axis x , it is necessary to consider the lateral offset of the aircraft's center of gravity coordinate, the lateral offset of the wind load vertical force, the wind load lateral force component, the wind load heading moment component, and the vertical component of the left and right engine thrust. Substituting these parameters into the equation gives:

[0132] △M x =-G·y g +F fz ·y f -F fy ·z f +M fx +(P l -P r )·F t ·sinα·y zf …………(5)

[0133] The unbalanced moment △M of the aircraft around the x-axis can be further calculatedx , the vertical load △F distributed to the left and right main landing gears:

[0134]

[0135] The numerical relationship of the vertical loads of the left and right main landing gear is established as follows:

[0136] F mz +△F=F my -△F…………(7)

[0137] By combining formulas (2), (4), and (7), we can calculate the vertical load F on the front landing gear. nz , vertical load F on left main landing gear mz , right main landing gear vertical load F my .

[0138] Steps for determining the nose wheel chock load to balance the heading force: Calculate the nose wheel chock load based on the aircraft heading force balance equation.

[0139] According to the balance relationship of the heading force (x-axis force), we can get:

[0140] ∑F x =0…………(8)

[0141] ∑F x The sum of the heading forces, where the heading force includes the left and right engine thrust P l F t 、P r F t Heading component, wind load heading force component F fx , the friction between the left and right main landing gear wheel brake tires and the ground f c1 and f c2 And the front wheel block load F to balance the heading force ld1 , then formula (8) can be expressed as:

[0142] F ld1 +f c1 +f c2 -(P l +P r )·F t ·cosα+F fx =0…………(9)

[0143] in,

[0144] Friction force f between the left and right main landing gear wheel brake tires and the ground c1 and f c2 , calculated according to the maximum static friction:

[0145] f c1 =μ·Fmz …………(10)

[0146] f c2 =μ·F my …………(11)

[0147] Steps for determining the nose wheel chock load to balance the turning moment: Calculate the nose wheel chock load based on the aircraft turning moment balance equation.

[0148] Although the nose wheel chock load is solved based on the aircraft's heading force balance relationship, considering that the asymmetric test of the engines on both sides of the aircraft may generate a large turning moment, this moment still needs to be balanced by the nose wheel chock load.

[0149] According to the balance equation of turning moment about the axis of rotation perpendicular to the ground during the asymmetric test of the aircraft, the load that the wheel chock needs to bear is calculated as follows:

[0150] ∑M z =0…………(12)

[0151] The aircraft's rotation axis around the vertical ground is on the extension line of the line connecting the thrust points of the two engines. Assuming that the rotation axis is located on the right side of the aircraft and the distance d from the aircraft's symmetry plane, both the left and right engines generate turning moments. The friction between the left and right main engine tires and the ground and the wheel block resistance provide the anti-rotation moment. Considering the wind load, formula (12) can be expressed as:

[0152]

[0153] in,

[0154] F ld2 To balance the turning moment, the front wheel chock load is applied.

[0155] The aircraft's rotation axis about the ground is on the right side of the aircraft. The distance d from the aircraft's symmetry plane can be determined by the thrust of the engines on both sides of the aircraft, as follows:

[0156]

[0157] The wheel resistance F used to balance the turning moment can be calculated by formula (13): ld2 .

[0158] The maximum load of the front wheel chock is determined by: determining the maximum load of the front wheel chock based on the front wheel chock load of the balanced heading force and the front wheel chock load of the balanced turning moment.

[0159] Since the aircraft has both a tendency to slide forward and a tendency to turn due to moment imbalance during the test run, the front wheel block load F can be used to balance the heading force. ld1 , balanced turning moment front wheel block load Fld2 The larger value of the two is taken as the maximum load F of the front wheel block ld In addition, since the above calculation uses the maximum static friction force, the calculated balanced heading force front start chock load and balanced turning moment front start chock load may be negative, indicating that the front start chock does not bear any load and the test run can be completed by braking alone.

[0160] Comparison of balanced heading force and front wheel block load F ld1 , balanced turning moment front wheel block load F ld2 If the balanced heading force is the front wheel block load F ld1 Less than the front wheel block load F of the balanced turning moment ld2 , then further determine the front wheel block load F before the balanced turning moment ld2 Is it less than 0? If so, the maximum load F of the front wheel block ld Take 0, if not, then the maximum load of the front wheel block F ld Take the wheel block load F before balancing the turning moment ld2 ;

[0161] If the wheel block load F before balancing the heading force ld1 Not less than the front wheel block load F of the balanced turning moment ld2 , then we can further determine the front wheel block load F of the balanced heading force ld1 Is it less than 0? If so, the maximum load F of the front wheel block ld Take 0, if not, then the maximum load of the front wheel block F ld Take the wheel block load F before balancing the heading force ld1 .

[0162] In a specific example, the aircraft test condition is the aircraft left engine test thrust percentage P l =100%; aircraft right engine test thrust percentage P r =60%; friction coefficient between tire and ground μ = 0.5; test oil volume M oil =1000kg; total aircraft mass M = 15000kg; atmospheric temperature T = 20℃; wind speed V = 5m / s; wind direction β = 90°.

[0163] The main geometric parameters of the aircraft test are as follows:

[0164] Aircraft center of gravity coordinates (x g =6m,y g =-0.05m,z g =0.5m);

[0165] Front wheel tire radius R q =0.3m;

[0166] Main wheel tire radius Rz =0.4m;

[0167] Front wheel axle center coordinates (x ql =1.2m,y ql =0m,z ql =-1.6m);

[0168] Left main wheel axle center point coordinates (x zl =7m,y zl =-2.5m,z zl =-1.6m);

[0169] Coordinates of the center point of the right main wheel axis (x yl =7m,y yl =2.5m,z yl =-1.6m);

[0170] Coordinates of the left engine thrust action point (x zf =6.8m,y zf =-2.6m,z zf =0.2m);

[0171] Coordinates of the right engine thrust action point (x yf =6.8m,y yf =2.6m,z yf =0.2m);

[0172] The angle between the engine thrust axis and the horizontal plane is α = 3°;

[0173] Coordinates of wind load action point (x f =5.5m,y f =0.1m,z f =0.4m).

[0174] Determine the necessary input parameter values ​​required for the aircraft test calculation conditions, including the single engine full power thrust value F corresponding to temperature T, wind speed V, and wind direction β t And the wind load action point (x f ,y f ,z f ) in the three perpendicular directions x, y, and z fx 、F fy 、F fz and the moment component M fx 、M fy 、M fz Etc., as shown in the following table:

[0175] Based on the method for determining the maximum load on the chocks before a test run of an aircraft disclosed in the above embodiment, the specific process of determining the maximum load on the chocks before a test run of an aircraft is as follows:

[0176] S1. Calculate the vertical load F of the front main landing gear according to formulas (2), (4), and (7): nz 、F mz 、F my have:

[0177]

[0178] According to formula (6):

[0179]

[0180] According to formula (5):

[0181] △M x =7350+20-200+1000-1632.9=6537.1…………(17)

[0182] Combining formulas (15)-(17) yields:

[0183]

[0184] S2. Calculate the front wheel block load F to balance the heading force according to formulas (9) to (11). ld1 have:

[0185] F ld1 +29890.4+28853.0-63912.3+100=0…………(18)

[0186] Calculate F ld1 =5068.9N.

[0187] S3. According to formula (13), calculate the front wheel block load F to balance the turning moment. ld2 have:

[0188]

[0189] According to formula (14):

[0190]

[0191] Combine formulas (19) and (20) to calculate F ld2 =-8154.3N.

[0192] S4. Due to F ld1 >F ld2 , and F ld1 >0, determine the maximum load F of the front wheel block during the test run ld =F ld1=5068.9N, to prevent the aircraft from sliding forward during test run.

[0193] The method for determining the maximum load of the front wheel chocks during an aircraft test run disclosed in the above-mentioned embodiment is based on the unbalanced state of relative sliding between the aircraft and the ground during a test run without wheel chocks. It comprehensively considers and theoretically calculates the load transmitted to the test wheel chocks by the landing gear under the action of multiple factors, and calculates and determines the maximum load of the front wheel chocks during an aircraft test run. The method is simple, clear, and has a sufficient theoretical basis. It comprehensively considers the wind load at different temperatures and wind speeds and the addition and removal of loads on the landing gear by the engine thrust. It can efficiently and relatively accurately determine the maximum load of the front wheel chocks during an aircraft test run, and can effectively guide the design of the front wheel chocks to avoid the situation where the maximum resistance of the designed front wheel chocks is too small or too large.

[0194] Another aspect provides a system for determining the maximum load of wheel blocks before aircraft test, characterized by comprising:

[0195] A front main landing gear vertical load determination module, used to determine the front main landing gear vertical load;

[0196] A module for determining the front wheel chock load for balancing the heading force is used to calculate the front wheel chock load based on the aircraft heading force balance equation;

[0197] A module for determining the front wheel chock load for balanced turning moment is used to calculate the front wheel chock load based on the aircraft turning moment balance equation;

[0198] The front wheel chock maximum load determination module is used to determine the front wheel chock maximum load based on the front wheel chock load of the balanced heading force and the front wheel chock load of the balanced turning moment.

[0199] Optionally, in the above-mentioned aircraft test run front wheel chock maximum load determination system, the front main landing gear vertical load determination module specifically includes:

[0200] F nz +F mz +F my +F fz -G=0;

[0201]

[0202] F mz +△F=F my -△F;

[0203] in,

[0204] F nz is the vertical load of the front landing gear; F mz is the vertical load of the left main landing gear; F my is the vertical load of the right main landing gear;

[0205] Ffx is the wind load heading force component; F fz is the vertical force component of wind load; M fy is the moment component of wind load around the y-axis; G is the aircraft gravity; F fz is the vertical component of wind load; P l P is the test thrust percentage of the left engine of the aircraft; r F is the test thrust percentage of the right engine of the aircraft; t is the full power thrust value of a single engine; α is the angle between the engine thrust axis and the horizontal plane; μ is the friction coefficient between the tire and the ground; R z Main landing gear tire radius; D nz 、D fx 、D fz 、D g 、D tz 、D tx They are the vertical forces F of the front landing gear nz , wind load heading force component F fx , vertical force component of wind load F fz , aircraft gravity G, and left and right engine thrust P l F t 、P r F t Moments of vertical and yaw force components to the main landing gear axles;

[0206] △F is the unbalanced moment △M of the aircraft around the x-axis x , vertical load distributed to the left and right main landing gear.

[0207] Optionally, in the aircraft test run front wheel chock maximum load determination system, in the front main landing gear vertical load determination module:

[0208]

[0209] in,

[0210] y zl 、y yl is the value of the coordinate of the center point of the left and right main landing gear axles in the y direction.

[0211] Optionally, in the aircraft test run front wheel chock maximum load determination system, in the front main landing gear vertical load determination module:

[0212] △M x =-G·y g +F fz ·y f -F fy ·z f +M fx +(P l -P r)·F t ·sinα·y zf ;

[0213] in,

[0214] y g 、y f 、y zf are the coordinates of the aircraft's center of gravity, the wind load action point, and the left engine's thrust action point in the y direction;

[0215] z f is the value of the coordinate of the wind load action point in the z direction;

[0216] F fy is the lateral force component of wind load;

[0217] M fx is the heading moment component of the wind load.

[0218] Optionally, in the above-mentioned system for determining the maximum load on the starting chocks before aircraft test, the module for determining the load on the starting chocks before balancing the yaw force is specifically as follows:

[0219] F ld1 +f c1 +f c2 -(P l +P r )·F t ·cosα+F fx =0;

[0220] in,

[0221] F ld1 To balance the heading force, the front wheel chock load;

[0222] f c1 、f c2 The friction between the left and right main landing gear wheel brake tires and the ground;

[0223] F fx is the heading force component of the wind load.

[0224] Optionally, in the above-mentioned system for determining the maximum load of the starting chocks before the aircraft test run, in the module for determining the starting chock load before the balanced heading force:

[0225] f c1 =μ·F mz ;

[0226] f c2 =μ·F my .

[0227] Optionally, in the above-mentioned system for determining the maximum load on the starting chock before aircraft test, the module for determining the starting chock load before balancing the turning moment is specifically as follows:

[0228]

[0229] in,

[0230] d is the distance from the aircraft's symmetry plane to the right of the aircraft, where the aircraft's rotation axis is perpendicular to the ground;

[0231] y yf is the value of the coordinate of the thrust action point of the right engine in the y direction;

[0232] x zf is the value of the coordinate of the thrust action point of the left engine in the x direction;

[0233] x f 、y f The coordinates of the wind load action point in the x and y directions

[0234] F ld2 To balance the turning moment, the front wheel chock load is applied.

[0235] Optionally, in the above-mentioned system for determining the maximum load on the starting chocks before aircraft test, in the module for determining the starting chock load before balancing the turning moment:

[0236]

[0237] y zf is the value of the coordinate of the thrust action point of the left engine in the y direction;

[0238] Optionally, in the above-mentioned system for determining the maximum load of the front wheel chock during aircraft test, the module for determining the maximum load of the front wheel chock is specifically as follows:

[0239] Comparison of balanced heading force and front wheel block load F ld1 , balanced turning moment front wheel block load F ld2 If the balanced heading force is the front wheel block load F ld1 Less than the front wheel block load F of the balanced turning moment ld2 , then further determine the front wheel block load F before the balanced turning moment ld2 Is it less than 0? If so, the maximum load F of the front wheel block ld Take 0, if not, then the maximum load of the front wheel block F ld Take the wheel block load F before balancing the turning moment ld2 ;

[0240] If the wheel block load F before balancing the heading force ld1 Not less than the front wheel block load F of the balanced turning moment ld2, then we can further determine the front wheel block load F of the balanced heading force ld1 Is it less than 0? If so, the maximum load F of the front wheel block ld Take 0, if not, then the maximum load of the front wheel block F ld Take the wheel block load F before balancing the heading force ld1 .

[0241] Regarding the system for determining the maximum load of the wheel chocks before an aircraft test run disclosed in the above-mentioned embodiment, since it corresponds to the method for determining the maximum load of the wheel chocks before an aircraft test run disclosed in the above-mentioned embodiment, the description is relatively simple. For specific related matters, please refer to the relevant description of the method for determining the maximum load of the wheel chocks before an aircraft test run. Its technical effects can also refer to the technical effects of the relevant parts of the method for determining the maximum load of the wheel chocks before an aircraft test run, and will not be repeated here.

[0242] In addition, technicians in the field should also be able to realize that the various modules of the device disclosed in the embodiments of the present application can be implemented by electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, this application generally describes them according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Technicians in the field can choose to adopt different methods to implement the described functions for each specific application and its actual constraints, but such implementation should not be considered to be beyond the scope of this application.

[0243] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or replacements to the relevant technical features, and the technical solutions after these changes or replacements will fall within the scope of protection of the present application.

Claims

1. A method for determining the maximum load of the wheel block before the aircraft test run, characterized in that: include: The steps for determining the vertical load of the front main landing gear are as follows: determining the vertical load of the front main landing gear; The steps for determining the front wheel chock load by balancing the heading force are as follows: Calculate the front wheel chock load according to the aircraft heading force balance equation; Steps for determining the front wheel chock load to balance the turning moment: Calculate the front wheel chock load based on the aircraft turning moment balance equation; The steps for determining the maximum load of the front wheel chock are as follows: based on the front wheel chock load of the balanced heading force and the front wheel chock load of the balanced turning moment, the maximum load of the front wheel chock is determined.

2. The method for determining the maximum load of the wheel block before the aircraft test run according to claim 1, characterized in that: The specific steps for determining the vertical load of the front main landing gear are: F nz +F mz +F my +F fz -G=0; F nz ·D nz +F fx ·D fx +F fz ·D fz +M fy -G·D g -(P l +P r )·F t ·D tz ·cosα+(P l +P r )·F t ·D tx ·sinα-μ(F mz +F my )·R z =0; F mz +△F=F my -△F; in, F nz is the vertical load of the front landing gear; F mz is the vertical load of the left main landing gear; F my is the vertical load of the right main landing gear; F fx is the wind load heading force component; F fz is the vertical force component of wind load; M fy is the moment component of wind load around the y-axis; G is the aircraft gravity; F fz is the vertical component of wind load; P l P is the test thrust percentage of the left engine of the aircraft; r F is the test thrust percentage of the right engine of the aircraft; t is the full power thrust value of a single engine; α is the angle between the engine thrust axis and the horizontal plane; μ is the friction coefficient between the tire and the ground; R z Main landing gear tire radius; D nz , D fx , D fz , D g , D tz , D tx They are the front landing gear vertical force F nz , wind load heading force component F fx , vertical force component of wind load F fz , aircraft gravity G, and left and right engine thrust P l F t , P r F t Moment of vertical force and yaw force components to the main landing gear axle; △F is the unbalanced moment △M of the aircraft around the x-axis x , vertical load distributed to the left and right main landing gear.

3. The method for determining the maximum load of the wheel block before the aircraft test run according to claim 2, characterized in that: In the steps of determining the vertical load of the front main landing gear: in, y zl ,y yl It is the value of the coordinate of the center point of the left and right main landing gear axles in the y direction.

4. The method for determining the maximum load of the wheel block before the aircraft test run according to claim 3, characterized in that: In the steps of determining the vertical load of the front main landing gear: △M x =-G·y g +F fz ·y f -F fy ·z f +M fx +(P l -P r )·F t ·sinα·y zf ; in, y g ,y f ,y zf are the coordinates of the aircraft center of gravity, the wind load action point, and the left engine thrust action point in the y direction; z f is the value of the coordinate of the wind load action point in the z direction; F fy is the lateral force component of wind load; M fx is the heading moment component of the wind load.

5. The method for determining the maximum load of the wheel block before the aircraft test run according to claim 4, characterized in that: The specific steps for determining the wheel block load before balancing the heading force are as follows: F ld1 +f c1 +f c2 -(P l +P r )·F t ·cosα+F fx =0; in, F ld1 To balance the heading force, the front wheel chock load; f c1 、f c2 It is the friction between the left and right main landing gear wheel brake tires and the ground; F fx is the heading force component of the wind load.

6. The method for determining the maximum load of the wheel block before the aircraft test run according to claim 5, characterized in that: In the steps of determining the wheel block load before balancing the heading force: f c1 =μ·F mz ; f c2 =μ·F my 。 7. The method for determining the maximum load of the wheel block before the aircraft test run according to claim 6, characterized in that: The specific steps for determining the front wheel block load to balance the turning moment are as follows: P l ·F t ·(d-y zf )+P r ·F t ·(d-y yf )+F fy ·(x zf -x f )=f c1 ·(d-y zl )+f c2 ·(d-y yl )+F fx ·(d-y f )+F ld2 ·d; in, d is the distance from the aircraft's symmetry plane to the right of the aircraft, where the aircraft's rotation axis is perpendicular to the ground; y yf is the value of the coordinate of the thrust action point of the right engine in the y direction; x zf is the value of the coordinate of the thrust action point of the left engine in the x direction; x f ,y f is the value of the wind load action point coordinates in the x and y directions F ld2 To balance the turning moment, the front wheel chock load is applied.

8. The method for determining the maximum load of the wheel block before the aircraft test run according to claim 7, characterized in that: Steps for determining the front wheel block load to balance the turning moment: y zf It is the value of the coordinate of the thrust action point of the left engine in the y direction.

9. The method for determining the maximum load of the wheel block before the aircraft test run according to claim 8, characterized in that: The specific steps for determining the maximum load of the front wheel chock are as follows: Comparison of balanced heading force Front wheel block load F ld1 , Balance turning moment front wheel block load F ld2 If the front wheel block load F is balanced ld1 Less than the balanced turning moment before the wheel block load F ld2 , then further determine the front wheel block load F of the balanced turning moment ld2 Is it less than 0? If so, the maximum load F of the front wheel block ld Take 0, if not, the maximum load of the front wheel block F ld Take the wheel block load F before the balanced turning moment ld2 ; If the wheel block load F before balancing the heading force ld1 Not less than the front wheel block load F of the balanced turning moment ld2 , then further determine the front wheel block load F of the balanced heading force ld1 Is it less than 0? If so, the maximum load F of the front wheel block ld Take 0, if not, the maximum load of the front wheel block F ld Take the wheel block load F before balancing the heading force ld1 .

10. A system for determining the maximum load of wheel blocks before aircraft test, characterized in that: include: A front main landing gear vertical load determination module, used to determine the front main landing gear vertical load; A module for determining the front wheel chock load for balancing the heading force is used to calculate the front wheel chock load according to the aircraft heading force balance equation; A module for determining the front wheel chock load for balanced turning moment, used to calculate the front wheel chock load according to the aircraft turning moment balance equation; The front wheel chock maximum load determination module is used to determine the front wheel chock maximum load based on the front wheel chock load of the balanced heading force and the front wheel chock load of the balanced turning moment.

11. The system for determining the maximum load of the wheel block before the aircraft test run according to claim 10, characterized in that: The specific vertical load determination module of the front main landing gear is: F nz +F mz +F my +F fz -G=0; F nz ·D nz +F fx ·D fx +F fz ·D fz +M fy -G·D g -(P l +P r )·F t ·D tz ·cosα+(P l +P r )·F t ·D tx ·sinα-μ(F mz +F my )·R z =0; F mz +△F=F my -△F; in, F nz is the vertical load of the front landing gear; F mz is the vertical load of the left main landing gear; F my is the vertical load of the right main landing gear; F fx is the wind load heading force component; F fz is the vertical force component of wind load; M fy is the moment component of wind load around the y-axis; G is the aircraft gravity; F fz is the vertical component of wind load; P l P is the test thrust percentage of the left engine of the aircraft; r F is the test thrust percentage of the right engine of the aircraft; t is the full power thrust value of a single engine; α is the angle between the engine thrust axis and the horizontal plane; μ is the friction coefficient between the tire and the ground; R z Main landing gear tire radius; D nz , D fx , D fz , D g , D tz , D tx They are the front landing gear vertical force F nz , wind load heading force component F fx , vertical force component of wind load F fz , aircraft gravity G, and left and right engine thrust P l F t , P r F t Moment of vertical force and yaw force components to the main landing gear axle; △F is the unbalanced moment △M of the aircraft around the x-axis x , vertical load distributed to the left and right main landing gear.

12. The system for determining the maximum load of the wheel block before the aircraft test run according to claim 11, characterized in that: In the front main landing gear vertical load determination module: in, y zl ,y yl It is the value of the coordinate of the center point of the left and right main landing gear axles in the y direction.

13. The system for determining the maximum load of the wheel block before the aircraft test run according to claim 12, characterized in that: In the front main landing gear vertical load determination module: △M x =-G·y g +F fz ·y f -F fy ·z f +M fx +(P l -P r )·F t ·sinα·y zf ; in, y g ,y f ,y zf are the coordinates of the aircraft center of gravity, the wind load action point, and the left engine thrust action point in the y direction; z f is the value of the coordinate of the wind load action point in the z direction; F fy is the lateral force component of wind load; M fx is the heading moment component of the wind load.

14. The system for determining the maximum load of the wheel block before the aircraft test run according to claim 13, characterized in that: The specific module for determining the wheel block load before balancing the heading force is: F ld1 +f c1 +f c2 -(P l +P r )·F t ·cosα+F fx =0; in, F ld1 To balance the heading force, the front wheel chock load; f c1 、f c2 It is the friction between the left and right main landing gear wheel brake tires and the ground; F fx is the heading force component of the wind load.

15. The system for determining the maximum load of the wheel block before the aircraft test run according to claim 14, characterized in that: In the module for determining the wheel block load before balancing the heading force: f c1 =μ·F mz ; f c2 =μ·F my 。 16. The system for determining the maximum load of the wheel block before the aircraft test run according to claim 15, characterized in that: The specific module for determining the wheel block load before balancing the turning moment is: P l ·F t ·(d-y zf )+P r ·F t ·(d-y yf )+F fy ·(x zf -x f )=f c1 ·(d-y zl )+f c2 ·(d-y yl )+F fx ·(d-y f )+F ld2 ·d; in, d is the distance from the aircraft's symmetry plane to the right of the aircraft, where the aircraft's rotation axis is perpendicular to the ground; y yf is the value of the coordinate of the thrust action point of the right engine in the y direction; x zf is the value of the coordinate of the thrust action point of the left engine in the x direction; x f ,y f is the value of the wind load action point coordinates in the x and y directions F ld2 To balance the turning moment, the front wheel chock load is applied.

17. The system for determining the maximum load of the wheel block before the aircraft test run according to claim 16, characterized in that: In the module for determining the wheel block load before balancing the turning moment: y zf It is the value of the coordinate of the thrust action point of the left engine in the y direction.

18. The system for determining the maximum load of the wheel block before the aircraft test run according to claim 17, characterized in that: The maximum load determination module of the front wheel block is as follows: Comparison of balanced heading force Front wheel block load F ld1 , Balance turning moment front wheel block load F ld2 If the front wheel block load F is balanced ld1 Less than the balanced turning moment before the wheel block load F ld2 , then further determine the front wheel block load F of the balanced turning moment ld2 Is it less than 0? If so, the maximum load F of the front wheel block ld Take 0, if not, the maximum load of the front wheel block F ld Take the wheel block load F before the balanced turning moment ld2 ; If the wheel block load F before balancing the heading force ld1 Not less than the front wheel block load F of the balanced turning moment ld2 , then further determine the front wheel block load F of the balanced heading force ld1 Is it less than 0? If so, the maximum load F of the front wheel block ld Take 0, if not, the maximum load of the front wheel block F ld Take the wheel block load F before balancing the heading force ld1 .

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