Aircraft landing gear anti-swing damping determination method and system

Abstract

The invention belongs to the technical field of aircraft landing gear design, and particularly relates to an aircraft landing gear anti-swing damping determination method and system, which considers structural friction damping, can quickly determine aircraft landing gear anti-swing damping, guides design and improvement of an aircraft landing gear, meets the iteration requirements of quick design and improvement of the aircraft landing gear, and avoids aircraft accidents.

Description

Technical Field

[0001] The present application belongs to the technical field of aircraft landing gear design, and in particular relates to a method and system for determining anti-sway damping of an aircraft landing gear. Background Art

[0002] Landing gear shimmy is a serious fault of an aircraft. Once the landing gear shimmy occurs during the taxiing process, it will not only cause the fuselage to shake or local parts to resonate, affecting the normal operation of the pilot, but also cause the shimmy lever, transmission mechanism, housing and its fixing device, landing gear, partial fracture of the fuselage structure, damage to wheels and tires, and even cause the aircraft to crash.

[0003] Determining the anti-sway damping of an aircraft landing gear is of great significance for the design and improvement of the landing gear and the avoidance of aircraft accidents. In this regard, currently, there is a lack of efficient and accurate determination methods for the anti-sway damping of an aircraft landing gear. In view of this, this application is proposed. Summary of the invention

[0001] The purpose of the present application is to provide a method and system for determining anti-sway damping of an aircraft landing gear, so as to overcome or alleviate at least one aspect of the known technical defects.

[0002] The technical solution of this application is:

[0003] On the one hand, a method for determining anti-sway damping of an aircraft landing gear is provided, comprising:

[0004] The steps of determining the anti-sway critical damping and the sway frequency are as follows: determining the anti-sway critical damping and the sway frequency of the landing gear;

[0005] The critical safety anti-sway damping determination step is as follows: based on the landing gear anti-sway critical damping, the critical safety anti-sway damping is determined;

[0006] The friction damping torque determination step is as follows: determining the friction damping torque along the axial direction of the buffer during the movement of the landing gear;

[0007] The steps of determining the equivalent damping of friction shimmy are as follows: determining the equivalent damping of friction shimmy according to the shimmy frequency of the landing gear and the friction damping torque along the axial direction of the buffer during its movement;

[0008] Steps for determining the anti-sway damping of the landing gear: Determine the anti-sway damping based on the critical safety anti-sway damping of the landing gear and the equivalent damping of the friction anti-sway damping.

[0009] According to at least one embodiment of the present application, in the above-mentioned method for determining the anti-sway damping of an aircraft landing gear, in the step of determining the anti-sway critical damping and the sway frequency, the landing gear sway motion differential equation group is used to solve the landing gear anti-sway critical damping and the sway frequency.

[0010] According to at least one embodiment of the present application, in the above-mentioned method for determining the anti-sway damping of an aircraft landing gear, the critical safety anti-sway damping determination step is specifically as follows:

[0011] h cr '=h cr ×σ;

[0012] in,

[0013] h cr 'It is the critical safety anti-sway damping of the landing gear;

[0014] h cr It is the critical damping of landing gear anti-sway;

[0015] σ is the safety factor.

[0016] According to at least one embodiment of the present application, in the above-mentioned method for determining the anti-sway damping of an aircraft landing gear, in the step of determining the critical safety anti-sway damping, the safety factor σ takes a value ≥ 2.0.

[0017] According to at least one embodiment of the present application, in the above-mentioned method for determining the anti-sway damping of an aircraft landing gear, the friction damping torque determination step is specifically as follows:

[0018] The friction damping torque along the axial direction of the buffer during the movement of the landing gear is obtained by experimental measurement; or

[0019] The friction damping torque along the buffer axis during the landing gear movement is estimated:

[0020] M = F × R;

[0021] in,

[0022] M is the friction damping torque along the axial direction of the buffer during the movement of the landing gear;

[0023] F is 10% of the vertical load during the landing gear movement;

[0024] R is the inner radius of the landing gear outer tube.

[0025] According to at least one embodiment of the present application, in the above-mentioned method for determining the anti-sway damping of an aircraft landing gear, in the step of determining the equivalent damping of friction anti-sway, based on the energy equivalence principle, the equivalent damping of friction anti-sway is calculated using the swing frequency of the landing gear and the friction damping torque along the axial direction of the buffer during its movement.

[0026] According to at least one embodiment of the present application, in the above-mentioned method for determining the anti-sway damping of an aircraft landing gear, the step of determining the friction anti-sway equivalent damping is specifically:

[0027]

[0028] in,

[0029] h mc is the equivalent damping of the friction reduction of the landing gear;

[0030] f is the landing gear shimmy frequency;

[0031] θ0 is the initial deflection angle of the landing gear wheels.

[0032] According to at least one embodiment of the present application, in the above-mentioned method for determining the anti-sway damping of an aircraft landing gear, the step of determining the anti-sway damping of the landing gear is specifically as follows:

[0033] h=h cr '-h mc ;

[0034] in,

[0035] h is the landing gear anti-sway damping.

[0036] On the other hand, a system for determining anti-sway damping of an aircraft landing gear is provided, comprising:

[0037] An anti-sway critical damping and sway frequency determination module, used to determine the anti-sway critical damping and sway frequency of the landing gear;

[0038] A critical safety anti-sway damping determination module, used to determine the critical safety anti-sway damping based on the landing gear anti-sway critical damping;

[0039] A friction damping torque determination module, used to determine the friction damping torque along the axial direction of the buffer during the movement of the landing gear;

[0040] A friction damping reduction equivalent damping determination module is used to determine the friction damping reduction equivalent damping according to the landing gear shimmy frequency and the friction damping torque along the axial direction of the buffer during its movement;

[0041] The landing gear anti-sway damping determination module is used to determine the anti-sway damping based on the landing gear critical safety anti-sway damping and the friction anti-sway equivalent damping.

[0042] According to at least one embodiment of the present application, in the above-mentioned aircraft landing gear anti-sway damping determination system, the anti-sway critical damping and sway frequency determination module uses the landing gear sway motion differential equation group to solve the landing gear anti-sway critical damping and sway frequency.

[0043] According to at least one embodiment of the present application, in the above-mentioned aircraft landing gear anti-sway damping determination system, the critical safety anti-sway damping determination module is specifically:

[0044] h cr '=h cr ×σ;

[0045] in,

[0046] h cr 'It is the critical safety anti-sway damping of the landing gear;

[0047] h cr It is the critical damping of landing gear anti-sway;

[0048] σ is the safety factor.

[0049] According to at least one embodiment of the present application, in the above-mentioned aircraft landing gear anti-sway damping determination system, in the critical safety anti-sway damping determination module, the safety factor σ takes a value ≥ 2.0.

[0050] According to at least one embodiment of the present application, in the above-mentioned aircraft landing gear anti-sway damping determination system, in the friction damping torque determination module, the friction damping torque along the axial direction of the buffer during the movement of the landing gear is estimated:

[0051] M = F × R;

[0052] in,

[0053] M is the friction damping torque along the axial direction of the buffer during the movement of the landing gear;

[0054] F is 10% of the vertical load during the landing gear movement;

[0055] R is the inner radius of the landing gear outer tube.

[0056] According to at least one embodiment of the present application, in the above-mentioned aircraft landing gear anti-sway damping determination system, in the friction anti-sway equivalent damping determination module, based on the energy equivalence principle, the friction anti-sway equivalent damping is calculated using the landing gear sway frequency and the friction damping torque along the axial direction of the buffer during its movement.

[0057] According to at least one embodiment of the present application, in the above-mentioned aircraft landing gear anti-sway damping determination system, the friction anti-sway equivalent damping determination module is specifically:

[0058]

[0059] in,

[0060] h mc is the equivalent damping of the friction reduction of the landing gear;

[0061] f is the landing gear shimmy frequency;

[0062] θ0 is the initial deflection angle of the landing gear wheels.

[0063] According to at least one embodiment of the present application, in the above-mentioned aircraft landing gear anti-sway damping determination system, the landing gear anti-sway damping determination module is specifically:

[0064] h=hcr '-h mc ;

[0065] in,

[0066] h is the landing gear anti-sway damping.

[0067] This application has at least the following beneficial technical effects:

[0068] Provided are a method and system for determining the anti-sway damping of an aircraft landing gear. The anti-sway damping of the aircraft landing gear can be quickly determined by taking into account the structural friction damping, so as to guide the design and improvement of the landing gear, meet the iterative requirements of rapid design and improvement of the landing gear, and avoid aircraft accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 is a schematic diagram of a method for determining anti-sway damping of an aircraft landing gear provided in an embodiment of the present application;

[0070] Figure 2 is a schematic diagram of a critical damping curve of landing gear anti-sway under different taxiing speed conditions provided in an embodiment of the present application;

[0071] Figure 3 is a schematic diagram of a landing gear shimmy frequency curve under different taxiing speed conditions provided in an embodiment of the present application;

[0072] Figure 4 It is a schematic diagram of an aircraft landing gear anti-sway damping determination system provided in an embodiment of the present application.

[0073] In order to better illustrate the present 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 construed as limitations on the present application. DETAILED DESCRIPTION

[0074] In order to make the technical solution and advantages of the present application clearer, the technical solution of the present application will be described in further detail in detail and in detail with reference to the accompanying drawings. It can be understood that the specific embodiments described here are only partial embodiments of the present application, which are only used to explain the present application, not to limit the present application. It should be noted that, for the convenience of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design.

[0075] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of this application shall have the usual meanings understood by those of ordinary skill in the art to which this application belongs. The words used in the description of this application to indicate orientation 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 indicates 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.

[0076] In addition, it should be noted that, unless otherwise clearly specified 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.

[0077] There is inevitably friction damping between the moving parts of the aircraft landing gear, especially the friction damping of the moving parts such as the piston rod rotating around the axis of the buffer strut, which has a great influence on the shimmy characteristics of the landing gear. At the same time, the friction damping of the aircraft landing gear moving structure will change with the wear caused by the use of the landing gear. When analyzing the shimmy characteristics of the landing gear, the effect of friction damping needs to be considered.

[0078] The friction damping between the moving parts of the aircraft landing gear is a nonlinear parameter. Its characteristics are that the magnitude of the friction damping is independent of the movement speed, the direction of the damping force is opposite to the direction of the relative movement of the structure, and the function describing this damping force is discontinuous and non-differentiable. It is difficult to describe this discontinuous motion phenomenon using the shimmy motion differential equation. It is necessary to convert the friction damping equivalent into a continuous and differentiable anti-shimmy damping function and substitute it into the shimmy motion differential equation group of the landing gear to perform the shimmy analysis.

[0079] Based on the above, the present application provides, on the one hand, a method for determining the anti-sway damping of an aircraft landing gear, which is a method for determining the anti-sway damping taking into account the structural friction damping, such as Figure 1 shown.

[0080] Steps for determining the anti-sway critical damping and sway frequency: Determine the anti-sway critical damping and sway frequency of the landing gear.

[0081] The landing gear shimmy motion differential equations are used to solve the landing gear anti-shimmy critical damping and shimmy frequency.

[0082] The differential equations of landing gear shimmy motion include tire dynamic parameters, landing gear torsional stiffness, landing gear lateral stiffness, etc.

[0083] In a specific example, the landing gear anti-sway critical damping and sway frequency under different taxiing speed conditions are obtained, such as Figure 2-3 shown.

[0084] The critical safety anti-sway damping is determined based on the landing gear anti-sway critical damping.

[0085] h cr '=h cr ×σ;

[0086] in,

[0087] h cr 'It is the critical safety anti-sway damping of the landing gear;

[0088] h cr It is the critical damping of landing gear anti-sway;

[0089] σ is the safety factor, and its value is ≥2.0.

[0090] The friction damping torque determination step is as follows: Determine the friction damping torque along the axial direction of the buffer during the movement of the landing gear.

[0091] The friction damping torque along the axial direction of the buffer during the movement of the landing gear can be obtained through experimental measurement.

[0092] The friction damping torque along the buffer axis during the landing gear movement can also be estimated:

[0093] M = F × R;

[0094] in,

[0095] M is the friction damping torque along the axial direction of the buffer during the movement of the landing gear;

[0096] F is 10% of the vertical load during the landing gear movement;

[0097] R is the inner radius of the landing gear outer tube.

[0098] The steps for determining the equivalent damping of friction sway reduction are as follows: the equivalent damping of friction sway reduction is determined based on the sway frequency of the landing gear and the friction damping torque along the axial direction of the buffer during its movement.

[0099] Based on the energy equivalence principle, the friction damping damping is calculated based on the landing gear shimmy frequency and the friction damping torque along the axial direction of the buffer during its movement:

[0100]

[0101] in,

[0102] h mc is the equivalent damping of the friction reduction of the landing gear;

[0103] f is the landing gear shimmy frequency;

[0104] θ0 is the initial deflection angle of the landing gear wheel. Different friction damping equivalent damping corresponds to different initial deflection angles.

[0105] Steps for determining the anti-sway damping of the landing gear: Determine the anti-sway damping based on the critical safety anti-sway damping of the landing gear and the equivalent damping of the friction anti-sway damping.

[0106] h=h cr '-h mc ;

[0107] in,

[0108] h is the landing gear anti-sway damping, that is, the minimum value of anti-sway damping that the landing gear turning and sway reduction control system should provide, corresponding to the minimum value of anti-sway damping designed for the landing gear turning and sway reduction control system.

[0109] In the method for determining the anti-sway damping of an aircraft landing gear disclosed in the above embodiment, the structural friction damping is taken into account, so that the anti-sway damping of the aircraft landing gear can be quickly determined, the design and improvement of the landing gear can be guided, the iterative requirements for rapid design and improvement of the landing gear can be met, and aircraft accidents can be avoided.

[0110] On the other hand, a system for determining anti-sway damping of an aircraft landing gear is provided, comprising:

[0111] An anti-sway critical damping and sway frequency determination module, used to determine the anti-sway critical damping and sway frequency of the landing gear;

[0112] A critical safety anti-sway damping determination module, used to determine the critical safety anti-sway damping based on the landing gear anti-sway critical damping;

[0113] A friction damping torque determination module, used to determine the friction damping torque along the axial direction of the buffer during the movement of the landing gear;

[0114] A friction damping reduction equivalent damping determination module is used to determine the friction damping reduction equivalent damping according to the landing gear shimmy frequency and the friction damping torque along the axial direction of the buffer during its movement;

[0115] The landing gear anti-sway damping determination module is used to determine the anti-sway damping based on the landing gear critical safety anti-sway damping and the friction anti-sway equivalent damping.

[0116] Optionally, in the above-mentioned aircraft landing gear anti-sway damping determination system, in the anti-sway critical damping and sway frequency determination module, the landing gear sway motion differential equation group is used to solve the landing gear anti-sway critical damping and sway frequency.

[0117] Optionally, in the above-mentioned aircraft landing gear anti-sway damping determination system, the critical safety anti-sway damping determination module is specifically:

[0118] h cr '=h cr ×σ;

[0119] in,

[0120] h cr 'It is the critical safety anti-sway damping of the landing gear;

[0121] h cr It is the critical damping of landing gear anti-sway;

[0122] σ is the safety factor.

[0123] Optionally, in the above-mentioned aircraft landing gear anti-sway damping determination system, in the critical safety anti-sway damping determination module, the safety factor σ is ≥2.0.

[0124] Optionally, in the above-mentioned aircraft landing gear anti-sway damping determination system, in the friction damping torque determination module, the friction damping torque along the axial direction of the buffer during the movement of the landing gear is estimated:

[0125] M = F × R;

[0126] in,

[0127] M is the friction damping torque along the axial direction of the buffer during the movement of the landing gear;

[0128] F is 10% of the vertical load during the landing gear movement;

[0129] R is the inner radius of the landing gear outer tube.

[0130] Optionally, in the above-mentioned aircraft landing gear anti-sway damping determination system, in the friction anti-sway equivalent damping determination module, based on the energy equivalence principle, the friction anti-sway equivalent damping is calculated using the landing gear sway frequency and the friction damping torque along the axial direction of the buffer during its movement.

[0131] Optionally, in the above-mentioned aircraft landing gear anti-sway damping determination system, the friction anti-sway equivalent damping determination module is specifically:

[0132]

[0133] in,

[0134] h mc is the equivalent damping of the friction reduction of the landing gear;

[0135] f is the landing gear shimmy frequency;

[0136] θ0 is the initial deflection angle of the landing gear wheels.

[0137] Optionally, in the above-mentioned aircraft landing gear anti-sway damping determination system, the landing gear anti-sway damping determination module is specifically:

[0138] h=h cr '-h mc ;

[0139] in,

[0140] h is the landing gear anti-sway damping.

[0141] As for the aircraft landing gear anti-sway damping determination system disclosed in the above-mentioned embodiment, since it corresponds to the aircraft landing gear anti-sway damping determination method disclosed in the above-mentioned embodiment, the description is relatively simple. For specific related matters, please refer to the relevant description of the part of the aircraft landing gear anti-sway damping determination method. Its technical effects can also refer to the technical effects of the relevant part of the aircraft landing gear anti-sway damping determination method, which will not be repeated here.

[0142] In addition, technicians in the field should also be able to realize that the various modules of the aircraft landing gear anti-sway damping determination system 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.

[0143] 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 substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the scope of protection of the present application.

Claims

1. A method for determining anti-sway damping of an aircraft landing gear, characterized in that: include: The steps of determining the anti-sway critical damping and the sway frequency are as follows: determining the anti-sway critical damping and the sway frequency of the landing gear; The critical safety anti-sway damping determination step is as follows: based on the landing gear anti-sway critical damping, the critical safety anti-sway damping is determined; The friction damping torque determination step is as follows: determining the friction damping torque along the axial direction of the buffer during the movement of the landing gear; The steps of determining the equivalent damping of friction shimmy are as follows: determining the equivalent damping of friction shimmy according to the shimmy frequency of the landing gear and the friction damping torque along the axial direction of the buffer during its movement; Steps for determining the anti-sway damping of the landing gear: Determine the anti-sway damping based on the critical safety anti-sway damping of the landing gear and the equivalent damping of the friction anti-sway damping.

2. The method for determining the anti-sway damping of an aircraft landing gear according to claim 1, characterized in that: In the step of determining the anti-sway critical damping and the sway frequency, the landing gear sway motion differential equation group is used to solve the anti-sway critical damping and the sway frequency of the landing gear.

3. The method for determining the anti-sway damping of an aircraft landing gear according to claim 2, characterized in that: The specific steps for determining critical safety anti-sway damping are as follows: h cr ’=h cr ×σ; in, h cr 'It is the critical safety anti-sway damping of the landing gear; h cr It is the critical damping of landing gear anti-sway; σ is the safety factor.

4. The method for determining the anti-sway damping of an aircraft landing gear according to claim 3, characterized in that: In the critical safety anti-sway damping determination step, the safety factor σ is taken as ≥2.

0.

5. The method for determining the anti-sway damping of an aircraft landing gear according to claim 4, characterized in that: The specific steps for determining the friction damping torque are: The friction damping torque along the axial direction of the buffer during the movement of the landing gear is obtained by experimental measurement; or The friction damping torque along the buffer axis during the landing gear movement is estimated: M = F × R; in, M is the friction damping torque along the axial direction of the buffer during the movement of the landing gear; F is 10% of the vertical load during the landing gear movement; R is the inner radius of the landing gear outer tube.

6. The method for determining the anti-sway damping of an aircraft landing gear according to claim 5, characterized in that: In the step of determining the friction shimmy equivalent damping, based on the energy equivalence principle, the friction shimmy equivalent damping is calculated using the shimmy frequency of the landing gear and the friction damping torque along the axial direction of the buffer during its movement.

7. The method for determining the anti-sway damping of an aircraft landing gear according to claim 6, characterized in that: The specific steps for determining the equivalent damping of friction damping are as follows: in, h mc is the equivalent damping of the friction reduction of the landing gear; f is the landing gear shimmy frequency; θ0 is the initial deflection angle of the landing gear wheels.

8. The method for determining the anti-sway damping of an aircraft landing gear according to claim 7, characterized in that: The specific steps for determining the landing gear anti-sway damping are as follows: h=h cr ’-h mc ; in, h is the landing gear anti-sway damping.

9. An aircraft landing gear anti-sway damping determination system, characterized in that: include: An anti-sway critical damping and sway frequency determination module, used to determine the anti-sway critical damping and sway frequency of the landing gear; A critical safety anti-sway damping determination module, used to determine the critical safety anti-sway damping based on the landing gear anti-sway critical damping; A friction damping torque determination module, used to determine the friction damping torque along the axial direction of the buffer during the movement of the landing gear; A friction damping reduction equivalent damping determination module is used to determine the friction damping reduction equivalent damping according to the landing gear shimmy frequency and the friction damping torque along the axial direction of the buffer during its movement; The landing gear anti-sway damping determination module is used to determine the anti-sway damping based on the landing gear critical safety anti-sway damping and the friction anti-sway equivalent damping.

10. The aircraft landing gear anti-sway damping determination system according to claim 9, characterized in that: In the anti-sway critical damping and sway frequency determination module, the landing gear sway motion differential equation group is used to solve the landing gear anti-sway critical damping and sway frequency.

11. The aircraft landing gear anti-sway damping determination system according to claim 10, characterized in that: In the critical safety anti-sway damping determination module, specifically: h cr ’=h cr ×σ; in, h cr 'It is the critical safety anti-sway damping of the landing gear; h cr It is the critical damping of landing gear anti-sway; σ is the safety factor.

12. The aircraft landing gear anti-sway damping determination system according to claim 11, characterized in that: In the critical safety anti-sway damping determination module, the safety factor σ is ≥ 2.

0.

13. The aircraft landing gear anti-sway damping determination system according to claim 12, characterized in that: In the friction damping torque determination module, the friction damping torque along the buffer axis during the landing gear movement is estimated: M = F × R; in, M is the friction damping torque along the axial direction of the buffer during the movement of the landing gear; F is 10% of the vertical load during the landing gear movement; R is the inner radius of the landing gear outer tube.

14. The aircraft landing gear anti-sway damping determination system according to claim 13, characterized in that: In the friction damping equivalent damping determination module, based on the energy equivalence principle, the friction damping equivalent damping is calculated using the landing gear shimmy frequency and the friction damping torque along the axial direction of the buffer during its movement.

15. The aircraft landing gear anti-sway damping determination system according to claim 14, characterized in that: In the friction-sway equivalent damping determination module, specifically: in, h mc is the equivalent damping of the friction reduction of the landing gear; f is the landing gear shimmy frequency; θ0 is the initial deflection angle of the landing gear wheels.

16. The aircraft landing gear anti-sway damping determination system according to claim 15, characterized in that: In the landing gear anti-sway damping determination module, specifically: h=h cr ’-h mc ; in, h is the landing gear anti-sway damping.

Images