Undercarriage dynamics modeling simulation method based on bonding graph principle

Abstract

The invention discloses an undercarriage dynamics modeling simulation method based on a bonding graph principle. The simulation method comprises the following steps: S1, constructing an undercarriage model; s2, simplifying the physical model; s3, creating a bonding graph model; s4, creating a state-space equation physical model; and S5, carrying out simulation solution. By adopting the modeling simulation method, the undercarriage is simplified into the four-mass physical model, the state-space equation of the four-mass physical model is established by utilizing a bonding graph principle, the state-space equation is established in simulation software, and simulation analysis is performed based on parameter setting, so that the operation efficiency of the model is improved; compared with a traditional method for obtaining modal parameters, the method is simpler, more direct and easy to operate, can accurately predict the reaction of the undercarriage to the ground in the sliding process in the initial stage of model design, can provide technical support for the stability of an airframe in the movement process, and is worthy of application and popularization.

Description

Technical Field

[0001] This invention relates to the field of aircraft structural dynamics modeling and simulation technology, specifically a landing gear dynamics modeling and simulation method based on the bond graph principle. Background Technology

[0002] In the design and development of landing gear, dynamic simulation analysis is a key means of evaluating its structural strength, stability, and reliability. Landing gear is usually an oil-gas hybrid structure, characterized by high nonlinearity and multi-physics coupling (mechanical, fluid, and thermal). Traditional calculation methods often use a two-mass model for linear dynamic analysis and differential equations for calculation. The calculation process is complex, lacks intuitiveness, and often fails to fully reflect the energy flow and dynamic interaction mechanism of the system.

[0003] With the development of computer simulation technology, the bond graph principle, as a graphical modeling tool for uniformly describing the energy flow and power exchange of systems (mechanical, hydraulic, and electrical), can clearly express the causal relationships and energy transfer paths between components in the system, and has been successfully applied in fields such as automotive suspension and robotics. However, a search reveals that there is currently no technical solution for applying the bond graph principle to the modeling and simulation of aircraft landing gear buffers, especially lacking modeling strategies and simulation processes for the complex nonlinear characteristics of oil-gas buffers.

[0004] Therefore, it is essential to use the bond graph principle to perform dynamic analysis on the landing gear, create state-space equations, conduct simulation analysis through software, and build a physical model based on the bond graph principle software AMESim for simulation analysis. This allows for comparison of the state-space equations and physical model analysis results, verifying the correctness of the model. Thus, it is necessary to provide a landing gear dynamic modeling and simulation method based on the bond graph principle. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the problems existing in the background art, thereby providing a dynamic modeling and simulation method for landing gear. This modeling and simulation method can be used to efficiently analyze the dynamic performance of landing gear during landing and taxiing, providing support for structural optimization design and performance evaluation. Specifically, it is a landing gear dynamic modeling and simulation method based on the bond graph principle.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a landing gear dynamics modeling and simulation method based on the bond graph principle, the simulation method comprising the following steps: S1. Construct a landing gear model. Based on the three-dimensional structural diagram of the landing gear, construct a state-space model for its use. S2. Simplify the physical model. Based on the constructed state-space model, and combined with the landing gear's performance parameters, usage status, and dynamic characteristics, the landing gear is simplified and decomposed into a representative four-mass model. S3. Create a bond graph model. Based on the bond graph principle, build a bond graph model in AMESim software. Based on the built bond graph model, convert it into a state space equation. S4. Create a physical model of the state-space equations. Based on the transformed state-space equations, use AMESim software to establish a physical model of the state-space equations. S5. Simulation Solution: Based on the established state-space equation physical model, AMESim software is used for simulation solution. Through parameter setting and simulation analysis, the results are evaluated and analyzed. If the displacement curve completely coincides with the displacement curve of the state-space equation, the result is output and the simulation analysis ends. If the result evaluation analysis shows that the two output curves cannot completely coincide, return to step S2 and readjust and optimize the constructed landing gear model until the result evaluation analysis satisfies that the two output curves completely coincide.

[0007] Furthermore, using the landing gear dynamics modeling and simulation method based on bond graph principle described in this invention, the landing gear in step S1 is a strut-type landing gear. The strut-type landing gear includes a strut, an outer cylinder, a buffer structure, an anti-torsion and anti-sway system, a piston rod, and wheels. Two wheels are provided, connected by a connecting shaft. The lower end of the piston rod is connected to the connecting shaft between the two wheels. The anti-torsion and anti-sway system is located between the connecting shaft and the buffer structure in the piston rod. The buffer structure is fitted inside the piston rod, the strut is mounted on the buffer structure, and the outer cylinder is fitted inside the piston rod above the buffer structure. The strut-type landing gear constructs a state-space model using the strut, outer cylinder, buffer structure, anti-torsion and anti-sway system, piston rod, and wheels.

[0008] Furthermore, in the landing gear dynamics modeling and simulation method based on the bond graph principle described in this invention, the specific operation method for simplifying and decomposing the landing gear into a representative four-mass model in step S2 is as follows: The mass of the outer cylinder, which consists of the strut, outer cylinder, and body, is simplified to mass block M1. The stiffness of the outer cylinder and the buffer structure is simplified to spring stiffness K1. The damping between the outer cylinder and the buffer structure, and the friction between the piston rod and the outer cylinder, are simplified to damping B1. The mass of the buffer structure oil is simplified to mass block M2. The stiffness of the buffer structure and the piston rod is simplified to spring stiffness K2. The damping between the buffer structure and the piston rod is simplified to damping B2. The mass of the anti-torsion and anti-sway system (connector) is simplified to mass block M3. The stiffness between the anti-torsion and anti-sway system and the outer cylinder and the piston rod is simplified to spring stiffness K3. The damping between the anti-torsion and anti-sway system and the outer cylinder and the piston rod is simplified to damping B3. The mass of the piston rod and the wheel is simplified to mass block M4. The vertical stiffness of the wheel is simplified to spring stiffness K4.

[0009] Furthermore, in the landing gear dynamics modeling and simulation method based on the bond graph principle described in this invention, during the creation of the bond graph model in step S3, the method for building the bond graph model based on the bond graph principle is to first define the physical model, and then draw the bond graph model according to the physical model parameter definition. The specific method for defining the physical model is as follows: Let X1 be the displacement of mass block M1, X5 be the velocity of mass block M1, and the spring stiffness K1 and damping B1 between mass blocks M1 and M2 be defined as positive for compression; X2 be the displacement of mass block M2, X6 be the velocity of mass block M2, and the spring stiffness K2 and damping B2 between mass blocks M2 and M3 be defined as positive for compression; X3 be the displacement of mass block M3, X7 be the velocity of mass block M3, and the spring stiffness K3 and damping B3 between mass block M3 and live mass block M4 be defined as positive for compression; X4 be the displacement of mass block M4, X8 be the velocity of mass block M4, and the spring stiffness K4 between mass block M4 and live mass block M4 be defined as positive for compression. The specific method for drawing the bond graph model is as follows: Based on the principles and basic rules of bond graphs, and combined with the definition of physical model parameters, a bond graph model is drawn. The outer cylinder M1, buffer oil M2, connecting part M3, piston rod, and tire M4 are defined as common flow junctions (1 junctions), while the spring stiffnesses K1, K2, K3, K4 and damping B1, B2, B3 are defined as common potential junctions (0 junctions). The compression of the spring stiffnesses K1, K2, K3, K4 and damping B1, B2, B3 is taken as the positive direction, and the velocity direction is drawn to obtain the bond graph model.

[0010] Furthermore, employing the landing gear dynamics modeling and simulation method based on the bond graph principle described in this invention, during the creation of the state-space equation physical model in step S4, the landing gear state-space equation is established based on the bond graph to state-space equation and the landing gear bond graph model. The specific method is as follows: The standard form of the state-space equations is: ; Among them, the displacement and velocity of mass blocks M1, M2, M3 and M4 are selected as state variables, the downward direction is defined as positive, multiple X state variables are set, and the displacement X1 of the outer cylinder M1 of the fuselage is obtained according to the state variables.

[0011] Furthermore, the landing gear dynamics modeling and simulation method based on the bond graph principle according to claim 5 of the present invention is characterized in that: in the process of creating the state-space equation physical model in step S4, a state-space equation simulation model is created according to the established landing gear state-space equation, and the specific operation method is as follows: In AMESim software, a state-space equation simulation model is established. This simulation model consists of an input signal u, a state-space equation, and a signal output terminal. The model parameters are set based on the weights of the selected mass blocks M1, M2, M3, and M4, as well as the values ​​of the spring stiffness K1, K2, K3, and K4 and the damping B1, B2, and B3. The set parameters form a matrix.

[0012] Furthermore, the landing gear dynamics modeling and simulation method based on the bond graph principle described in this invention is characterized in that: in the simulation solution process in step S5, according to the established state-space equation physical model, the AMESim software is used for simulation solution. The analysis result focuses on evaluating the displacement X1 of the fuselage outer cylinder M1. In the AMESim software, the input parameters of the output parameter signal output terminal are used to determine the displacement X1. If the displacement X1 of the fuselage outer cylinder M1 is in a decaying stable state under the influence of external loads, the response of the displacement X1 of the fuselage outer cylinder M1 can be adjusted by adjusting the spring stiffness and damping parameters, thereby obtaining the state-space equation simulation result.

[0013] Furthermore, in the landing gear dynamics modeling and simulation method based on the bond graph principle described in this invention, the specific operation of creating the physical model and solving the simulation in step S5 is as follows: The model needs to be built based on 10 factors: zero force source, mass block M1, spring damping blocks K1, B1, mass block M2, spring damping blocks K2, B2, mass block M3, spring damping blocks K3, B3, mass block M4, spring K4, and fixed force source. The analysis focuses on evaluating the displacement X1 of the fuselage outer cylinder M1. In AMESim software, the displacement parameters of the output mass block M1 are used to determine the output results. If the displacement X1 of the fuselage outer cylinder M1 is in a decaying stable state under the influence of external loads, the response of the displacement X1 of the fuselage outer cylinder M1 can be adjusted by adjusting the spring and damping parameters, thereby obtaining the state-space equation simulation results.

[0014] Furthermore, in the landing gear dynamics modeling and simulation method based on the bond graph principle described in this invention, during the simulation solution process in step S5, the specific method for evaluating and analyzing the results is to perform a comparative analysis of the model results. The operation method is to plot the displacement X1 of the fuselage outer cylinder M1 and the displacement parameters of the mass block M1 in the state space equation on the same graph. If the two output curves completely overlap, it indicates the correctness of converting the state space equation using the bond graph. If the comparative analysis of the model results shows that the two output curves cannot completely overlap, then return to step S2, and readjust and optimize the landing gear model constructed until the result evaluation analysis satisfies that the two output curves completely overlap.

[0015] The landing gear dynamics modeling and simulation method based on the bond graph principle described in this invention has the following advantages compared with the prior art: By simplifying the landing gear into a four-mass physical model, establishing the state-space equation of the four-mass physical model using the bond graph principle, establishing the state-space equation in the simulation software, and performing simulation analysis based on parameter settings, the computational efficiency of the model is improved. Furthermore, by establishing the four-mass physical model in AMESim and determining whether its displacement curve completely coincides with the displacement curve of the state-space equation through parameter settings and simulation analysis, the limitations of the prior art in multi-physics coupling modeling are overcome, achieving efficient and accurate simulation of the dynamic behavior of the buffer, improving the efficiency of system design and verification, and can be used to efficiently analyze the dynamic performance of the landing gear during landing and taxiing, providing support for structural optimization design and performance evaluation.

[0016] Therefore, the modeling and simulation method described in this invention simplifies the landing gear into a four-mass physical model, establishes the state-space equations of the four-mass physical model using the bond graph principle, establishes the state-space equations in the simulation software, and performs simulation analysis based on parameter settings. This improves the computational efficiency of the model. Compared with traditional methods for obtaining modal parameters, this method is simpler, more direct, and easier to operate. It can accurately predict the landing gear's response to the ground during takeoff in the early stages of model design and can provide technical support for the stability of the aircraft during motion. It is worthy of widespread application. Attached Figure Description

[0017] The present invention will now be described in further detail with reference to the accompanying drawings.

[0018] Figure 1 This is a schematic diagram of the technical route described in this invention; Figure 2 This is a structural model diagram of the landing gear described in this invention; Figure 3 This is a simplified model diagram of an existing landing gear with two masses; Figure 4 This is a simplified model diagram of the four-mass landing gear described in this invention; Figure 5 This is a schematic diagram of the bonding graph model simulation creation process described in the invention; Figure 6 This is a schematic diagram illustrating the definition of physical model parameters as described in this invention; Figure 7 This is a schematic diagram of the landing gear bonding diagram model described in the invention; Figure 8 This is a schematic diagram of the state-space equation simulation model described in this invention; Figure 9 The state-space equation simulation of the M1 displacement diagram described in the invention; Figure 10 This is the physical model diagram described in this invention; Figure 11 This is a schematic diagram of the simulation results of the physical model described in the invention; Figure 12 This is a comparison diagram of the physical model described in the invention and the state-space equation M1 displacement.

[0019] The figure shows: 1-strut, 2-outer cylinder, 3-buffer structure, 4-anti-torsion and anti-sway system, 5-piston rod, 6-wheel. Detailed Implementation

[0020] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0021] It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness or purpose of the invention, should still fall within the scope of the disclosed technical content. Furthermore, the terms "upper," "lower," "left," and "right" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0022] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connection" and "provided with" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0023] It should be noted that the term "comprising" or any other variation is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0024] This invention provides a landing gear dynamics modeling and simulation method based on the bond graph principle. The simulation method includes the following steps: S1. Construct a landing gear model. Based on the three-dimensional structural diagram of the landing gear, construct a state-space model for its use. S2. Simplify the physical model. Based on the constructed state-space model, and combined with the landing gear's performance parameters, usage status, and dynamic characteristics, the landing gear is simplified and decomposed into a representative four-mass model. S3. Create a bond graph model. Based on the bond graph principle, build a bond graph model in AMESim software. Based on the built bond graph model, convert it into a state space equation. S4. Create a physical model of the state-space equations. Based on the transformed state-space equations, use AMESim software to establish a physical model of the state-space equations. S5. Simulation Solution: Based on the established state-space equation physical model, AMESim software is used for simulation solution. Through parameter setting and simulation analysis, the results are evaluated and analyzed. If the displacement curve completely coincides with the displacement curve of the state-space equation, the result is output and the simulation analysis ends. If the result evaluation analysis shows that the two output curves cannot completely coincide, return to step S2 and readjust and optimize the constructed landing gear model until the result evaluation analysis satisfies that the two output curves completely coincide. Example

[0025] To further illustrate the landing gear dynamics modeling and simulation method based on bond graph principles described in this invention, which overcomes the limitations of existing technologies in multiphysics coupling modeling, achieves efficient and accurate simulation of the dynamic behavior of the buffer, and improves system design and verification efficiency, this invention simplifies the landing gear into a four-mass physical model. Using the bond graph principle, a state-space equation for this four-mass physical model is established. This state-space equation is then established in simulation software, and simulation analysis is performed based on parameter settings, improving the model's computational efficiency. A four-mass physical model is then established in AMESim software. Through parameter settings and simulation analysis, it is determined whether the displacement curve completely coincides with the displacement curve in the state-space equation, thus verifying the correctness of the dynamic model.

[0026] Taking strut-type landing gear as an example, the technical approach it adopts is as follows: Figure 1 As shown, the specific steps include: 1. Landing gear model The physical structure of a strut landing gear is as follows Figure 2 As shown, the main components are a strut 1, an outer cylinder 2, a buffer structure 3, an anti-torsion and anti-sway system 4, a piston rod 5, and wheels 6. There are two wheels 6 connected by a connecting shaft. The lower end of the piston rod 5 is connected to the connecting shaft between the two wheels 6. The anti-torsion and anti-sway system 4 is located between the connecting shaft and the buffer structure 3 in the piston rod 5. The buffer structure 3 is fitted inside the piston rod 5, the strut 1 is mounted on the buffer structure 3, and the outer cylinder 2 is fitted inside the piston rod 5 above the buffer structure 3. The strut-type landing gear constructs a state-space model of its use through the strut 1, outer cylinder 2, buffer structure 3, anti-torsion and anti-sway system 4, piston rod 5, and wheels 6.

[0027] 2. Simplify the physical model The landing gear is typically simplified to a two-mass model, such as... Figure 3 As shown, the masses of the strut 1, outer cylinder 2, buffer structure 3, anti-torsion and anti-sway system 4, and the machine body are simplified to mass block M1; the buffer structure 3 is simplified to spring stiffness K1; the damping of the buffer structure 3 and the friction between the piston rod 5 and the outer cylinder 2 are simplified to damping B1; the masses of the piston rod 5 and the wheel 6 are simplified to mass block M2; and the vertical stiffness of the wheel 6 is simplified to spring stiffness K2. However, the two-mass model used, because it does not consider the dynamic characteristics of the buffer structure 3 and the anti-torsion and anti-sway system 4, can generally only be applied to simple linear analysis.

[0028] This embodiment simplifies the landing gear into a four-mass model, as shown in the following figure. Figure 4 As shown, the mass of the support rod 1, outer cylinder 2, and body is simplified to mass block M1; the stiffness of the outer cylinder 2 and buffer structure 3 is simplified to spring stiffness K1; the damping between the outer cylinder 2 and buffer structure 3, and the friction between the piston rod 5 and outer cylinder 2 are simplified to damping B1; the mass of the oil in the buffer structure 3 is simplified to mass block M2; the stiffness of the buffer structure 3 and piston rod 5 is simplified to spring stiffness K2; the damping between the buffer structure 3 and piston rod 5 is simplified to damping B2; the mass of the anti-torsion and anti-sway system 4 is simplified to mass block M3; the stiffness between the anti-torsion and anti-sway system 4 and the outer cylinder 2 and piston rod 5 is simplified to spring stiffness K3; the damping between the anti-torsion and anti-sway system 4 and the outer cylinder 2 and piston rod 5 is simplified to damping B3; the mass of the piston rod 5 and wheel 6 is simplified to mass block M4; and the vertical stiffness of wheel 6 is simplified to spring stiffness K4.

[0029] 3. Create a bond graph model Since bond graphs are a highly effective dynamic modeling method that can uniformly handle engineering systems across multiple energy ranges, their basic function is to transform physical models into mathematical models, i.e., state-space equations or block diagrams. This embodiment uses state-space equations, and the bond graph model simulation creation process is as follows: Figure 5 As shown.

[0030] 3.1 Defining the Physical Model X1 is defined as the displacement of the outer casing M1, X5 as the velocity of the outer casing M1, and the stiffness K1 and damping B1 between the outer casing M1 and the buffer oil M2 are defined as positive under compression. X2 is defined as the displacement of the buffer oil M2, X6 as the velocity of the buffer oil M2, and the stiffness K2 and damping B2 between the buffer oil M2 and the connecting piece M3 are defined as positive under compression. X3 is defined as the displacement of the connecting piece M3, X7 as the velocity of the connecting piece M3, and the stiffness K3 and damping B3 between the connecting piece M3 and the piston rod and tire M4 are defined as positive under compression. X4 is defined as the displacement of the connecting piece M4, X8 as the velocity of the connecting piece M4, and the stiffness K4 between the piston rod and tire M4 and the fixed connection is defined as positive under compression. The specific physical model parameter definitions and structural diagram are shown below. Figure 6 As shown.

[0031] 3.2 Drawing the bond graph model Based on the principles and basic rules of bond graphs, and according to the definition of physical model parameters, a landing gear bond graph model is drawn, and its structural schematic diagram is shown below. Figure 7 As shown, the outer cylinder M1, buffer oil M2, connecting part M3, piston rod and wheel M4 are defined as common flow junctions (1 junction), and the spring stiffnesses K1, K2, K3, K4 and damping B1, B2, B3 are defined as common potential junctions (0 junction). The compression of the spring stiffnesses K1, K2, K3, K4 and damping B1, B2, B3 is taken as the positive direction. The velocity direction is drawn, and the direction of potential (force) is drawn in combination with the bond drawing annotation rules.

[0032] 3.3 Bond graph to state-space equation Based on the bond graph to state-space equations and the landing gear bond graph model, the landing gear state-space equations are established, in the following specific form.

[0033] The standard form of the state-space equation is ; The displacements and velocities of mass blocks M1, M2, M3, and M4 are selected as state variables, and their definitions are as follows: Figure 6 As shown, downward is defined as positive, and 8 state variables are set: ; Its differential relation is:

[0034] Where g is the gravitational acceleration, which is used as the input variable u, and the expression for matrix A is: ; The displacement X1 of the outer cylinder M1 of the output fuselage can be determined according to the standard form of the state-space equation; 3.4 Creating a State-Space Equation Simulation Model A state-space equation simulation model is established in AMESim software. The structure of the state-space equation simulation model is as follows: Figure 8 As shown, it consists of 1. input signal u①, state-space equation ②, and signal output terminal ③.

[0035] The model parameters are set as follows: M1 = 2000 kg, M2 = 3 kg, M3 = 1 kg, M4 = 30 kg; K1 = 200000 N / m, K2 = 318000 N / m, K3 = 133000 N / m, K4 = 1750000 N / m; B1 = 383 N / (m / s), B2 = 441 N / (m / s), B3 = 286 N / (m / s); Based on the expression for matrix A, the parameters of matrix A can be obtained.

[0036] As for the parameter settings of state-space equation ②, the parameters of matrices B, C and D can be obtained by following the same procedure as above. 3.5 Simulation Results of State-Space Equations The analysis results focus on evaluating the displacement X1 of the outer fuselage cylinder M1. In the AMESim software, the input parameters are output as output parameter signals to terminal ③. The output result is the state-space equation simulation displacement diagram of M1, as shown below. Figure 9 As shown, the displacement X1 of the outer casing M1 is in a decaying and stable state under the influence of external loads. The response of the displacement X1 of the outer casing M1 can be adjusted by adjusting the spring and damping parameters.

[0037] 4. Creating the physical model and solving the problem In AMESim, a physics model is built using 10 components. The specific model is as follows: Figure 10As shown, the physical model parameters are set as follows: M1 = 2000 kg, M2 = 3 kg, M3 = 1 kg, M4 = 30 kg, K1 = 200000 N / m, K2 = 318000 N / m, K3 = 133000 N / m, K4 = 1750000 N / m, B1 = 383 N / (m / s), B2 = 441 N / (m / s), and B3 = 286 N / (m / s). Wherein, ① is the zero force source, ② is mass block M1, ③ are spring damping blocks K1 and B1, ④ is mass block M2, ⑤ are spring damping blocks K2 and B2, ⑥ is mass block M3, ⑦ are spring damping blocks K3 and B3, ⑧ is mass block M4, ⑨ is spring K4, and ⑩ is the fixed force source.

[0038] The analysis results focus on evaluating the displacement X1 of the outer fuselage cylinder M1. In the AMESim software, the displacement parameters of the output mass block M1 are shown below. Figure 11 As shown, the displacement X1 of the outer casing M1 is in a decaying and stable state under the influence of external loads. The response of the displacement X1 of the outer casing M1 can be adjusted by adjusting the spring and damping parameters.

[0039] 5. Comparative Analysis of Model Results The displacement X1 of the fuselage outer cylinder M1 and the displacement parameters of the mass block M1 in the state-space equations are plotted on the same graph, such as... Figure 12 As shown, the two output curves completely overlap, proving the correctness of using the bond graph to transform into a state-space equation.

[0040] Therefore, the modeling and simulation method described in this invention simplifies the landing gear into a four-mass physical model, establishes the state-space equation of the four-mass physical model using the bond graph principle, establishes the state-space equation in the simulation software, and performs simulation analysis based on parameter settings. This improves the computational efficiency of the model. Furthermore, by establishing the four-mass physical model in AMESim and determining whether its displacement curve completely coincides with the displacement curve of the state-space equation through parameter settings and simulation analysis, the limitations of existing technologies in multi-physics coupling modeling are overcome. This enables efficient and accurate simulation of the dynamic behavior of the buffer, improves the efficiency of system design and verification, and can be used to efficiently analyze the dynamic performance of the landing gear during landing and taxiing, providing support for structural optimization design and performance evaluation.

[0041] In summary, the modeling and simulation method described in this invention simplifies the landing gear into a four-mass physical model, establishes the state-space equations of the four-mass physical model using the bond graph principle, establishes the state-space equations in simulation software, and performs simulation analysis based on parameter settings. This improves the computational efficiency of the model. Compared with traditional methods for obtaining modal parameters, this method is simpler, more direct, and easier to operate. It can accurately predict the landing gear's response to the ground during takeoff in the early stages of model design and can provide technical support for the stability of the aircraft during motion. It is worthy of widespread application.

[0042] Other aspects of this invention that are not detailed herein are all conventional techniques known to those skilled in the art.

[0043] The scope of protection of this invention is not limited to the technical solutions disclosed in the specific embodiments. The above description is only a preferred embodiment of this invention and does not limit this invention. Any minor modifications, equivalent substitutions and improvements made based on the technical solutions of this invention should be included within the scope of protection of the technical solutions of this invention.

Claims

1. A landing gear dynamics modeling and simulation method based on the bond graph principle, characterized in that, The simulation method comprises the following steps: S1. Constructing a landing gear model, constructing a state space model according to the three-dimensional structure diagram of the landing gear; S2. Simplifying the physical model, according to the constructed state space model, combining the performance parameters, use state and dynamic characteristics of the landing gear, the landing gear is simplified and decomposed into a representative four-mass model; S3. Create a bond graph model, build a bond graph model in AMESim software based on the principle of bond graph, and convert the bond graph model into a state space equation according to the built bond graph model; S4. Create a state space equation physical model, according to the converted state space equation, establish a state space equation physical model by using AMESim software; S5. Simulation solution, according to the established state space equation physical model, using AMESim software for simulation solution, through parameter setting and simulation analysis, result evaluation analysis, if the displacement curve and the displacement curve of the state space equation are completely overlapped, then output the result, end the simulation analysis; If the result evaluation analysis is that the two output curves cannot be completely overlapped, then return to step S2, adjust and optimize the landing gear model according to the constructed landing gear model, until the result evaluation analysis meets the two output curves completely overlapped.

2. The landing gear dynamic modeling and simulation method based on the bond graph principle according to claim 1, characterized in that: The landing gear in step S1 adopts a strut type landing gear, which comprises a strut (1), an outer cylinder (2), a buffer structure (3), a anti-twist and anti-sway system (4), a piston rod (5) and a wheel (6), wherein the wheel (6) is provided with two, the two wheels (6) are connected by a connecting shaft, the lower end of the piston rod (5) is connected with the connecting shaft between the two wheels (6), and the anti-twist and anti-sway system (4) is arranged between the connecting shaft and the buffer structure (3) in the piston rod (5); the buffer structure (3) is sleeved in the piston rod (5), the strut (1) is arranged on the buffer structure (3), and the outer cylinder (2) is sleeved in the piston rod (5) above the buffer structure (3), and the strut type landing gear is constructed by the strut (1), the outer cylinder (2), the buffer structure (3), the anti-twist and anti-sway system (4), the piston rod (5) and the wheel (6).

3. The landing gear dynamic modeling and simulation method based on bond graph principles according to claim 2, characterized in that: In the process of simplifying the physical model in step S2, the specific operation mode of simplifying and decomposing the landing gear into a representative four-mass model is: The mass of the strut (1), the outer cylinder (2) and the body is simplified as a mass block (M1), the stiffness of the outer cylinder (2) and the buffer structure (3) is simplified as spring stiffness (K1), the damping between the outer cylinder (2) and the buffer structure (3) and the friction between the piston rod (5) and the outer cylinder (5) is simplified as damping (B1), the mass of the buffer structure (3) oil, i.e. the buffer oil, is simplified as a mass block (M2), the stiffness of the buffer structure (3) and the piston rod (5) is simplified as spring stiffness (K2), the damping between the buffer structure (3) and the piston rod (5) is simplified as damping (B2), the mass of the anti-twist and roll reduction system (4), i.e. the connecting piece, is simplified as a mass block (M3), the stiffness between the anti-twist and roll reduction system (4) and the outer cylinder (2) and the piston rod (5) is simplified as spring stiffness (K3), the damping between the anti-twist and roll reduction system (4) and the outer cylinder (2) and the piston rod (5) is simplified as damping (B3), the mass of the piston rod (5) and the wheel (6) is simplified as a mass block (M4), and the vertical stiffness of the wheel (6) is simplified as spring stiffness (K4).

4. The landing gear dynamic modeling and simulation method based on bond graph principles according to claim 3, characterized in that: In the process of creating the bond graph model in the step S3, the method of building the bond graph model based on the bond graph principle is to define a physical model, and then draw the bond graph model according to the physical model parameter definition, wherein the specific method of defining the physical model is as follows: X1 is defined as the displacement of the mass block (M1), X5 is defined as the speed of the mass block (M1), the spring stiffness (K1) and the damping (B1) between the mass block (M1) and the mass block (M2) are defined as compression to positive; X2 is defined as the displacement of the mass block (M2), X6 is defined as the speed of the mass block (M2), the spring stiffness (K2) and the damping (B2) between the mass block (M2) and the mass block (M3) are defined as compression to positive; X3 is defined as the displacement of the mass block (M3), X7 is defined as the speed of the mass block (M3), the spring stiffness (K3) and the damping (B3) between the mass block (M3) and the mass block (M4) are defined as compression to positive; X4 is defined as the displacement of the mass block (M4), X8 is defined as the speed of the mass block (M4), and the spring stiffness (K4) and the mass block (M4) are defined as compression to positive; The specific method of drawing the bond graph model is as follows: According to the bond graph principle and the basic rules, the bond graph model is drawn by combining the physical model parameter definition, defining the body outer cylinder (M1), the buffer oil (M2), the connecting piece (M3), the piston rod and the tire (M4) as common flow junctions (1 junctions), defining the spring stiffness (K1, K2, K3, K4) and the damping (B1, B2, B3) as common potential junctions (0 junctions), defining the compression of the spring stiffness (K1, K2, K3, K4) and the damping (B1, B2, B3) as positive direction, and drawing the speed direction, so as to obtain the bond graph model.

5. The landing gear dynamic modeling and simulation method based on bond graph principles according to claim 4, characterized in that: In the process of creating the state space equation physical model in the step S4, the landing gear state space equation is established according to the bond graph to state space equation and the landing gear bond graph model, and the specific method is as follows: The standard form of the state space equation is: ； Wherein, the displacement and velocity of the selected mass (M1, M2, M3, M4) are state variables, the downward direction is defined as positive, a plurality of X state variables are set, and the state variables are defined, thereby obtaining the displacement X1 of the fuselage outer cylinder (M1).

6. The landing gear dynamic modeling and simulation method based on bond graph principles according to claim 5, characterized in that: In the step S4, the state space equation physical model is created according to the established landing gear state space equation, and the specific operation method is: In the AMESim software, the state space equation simulation model is established, which is composed of an input signal u, a state space equation and a signal output terminal, and the model parameters are determined according to the weight of the selected mass (M1, M2, M3, M4), and the numerical values of the spring stiffness (K1, K2, K3, K4) and the damping (B1, B2, B3), and the matrix is formed by the set parameters.

7. The landing gear dynamic modeling and simulation method based on bond graph principles according to claim 6, characterized in that: In the simulation solving process in the step S5, the AMESim software is used for simulation solving according to the established state space equation physical model, and the analysis result is the displacement (X1) of the fuselage outer cylinder (M1), which is determined by the input parameters of the output parameter signal output terminal in the AMESim software. If the displacement (X1) of the fuselage outer cylinder (M1) is in a decaying stable state under the influence of external load, the displacement (X1) of the fuselage outer cylinder (M1) can be adjusted by adjusting the spring stiffness and damping parameters, thereby obtaining the state space equation simulation result.

8. The landing gear dynamic modeling and simulation method based on bond graph principles according to claim 7, characterized in that: In the simulation solving process in the step S5, the specific operation method of creating a physical model and solving process is that the model needs to be built according to the zero force source, the mass (M1), the spring damping block (K1, B1), the mass (M2), the spring damping block (K2, B2), the mass (M3), the spring damping block (K3, B3), the mass (M4), the spring (K4) and the fixed force source, and the analysis result is the displacement (X1) of the fuselage outer cylinder (M1), which is determined by the displacement parameter of the output mass (M1) in the AMESim software. If the displacement (X1) of the fuselage outer cylinder (M1) is in a decaying stable state under the influence of external load, the displacement (X1) of the fuselage outer cylinder (M1) can be adjusted by adjusting the spring and damping parameters, thereby obtaining the state space equation simulation result.

9. The landing gear dynamic modeling and simulation method based on bond graph principles according to claim 8, characterized in that: In the simulation solving process in the step S5, the specific way of result evaluation analysis is model result comparison analysis, and the operation method is that the displacement (X1) of the fuselage outer cylinder (M1) and the displacement parameter of the mass (M1) of the state space equation are plotted in the same chart, such as two output curves completely coinciding, which indicates the correctness of the state space equation converted from the bond graph; if the model result comparison analysis shows that the two output curves cannot completely coincide, return to the step S2, and adjust and optimize the constructed landing gear model again until the result evaluation analysis satisfies the two output curves completely coinciding.

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