A method for designing an installation structure of an aircraft inertial navigation device

Abstract

The application belongs to the technical field of aircraft inertial navigation equipment mounting structure design, and particularly relates to a kind of aircraft inertial navigation equipment mounting structure design method, which can realize lightweight design of mounting structure while meeting the mounting frequency requirement of inertial navigation equipment, and can efficiently design mounting structure meeting low-frequency vibration isolation requirement and effectively controlling weight.

Description

Technical Field

[0001] This application belongs to the technical field of aircraft inertial navigation equipment installation structure design, specifically relating to a design method for an aircraft inertial navigation equipment installation structure. Background Technology

[0002] Inertial navigation equipment provides the flight control system with measurement data such as pitch, roll, and yaw angles to ensure stable flight of the aircraft. It is an important electronic device that affects the safety of aircraft flight.

[0003] Aircraft inertial navigation systems are typically equipped with vibration damping systems to isolate the effects of aircraft vibrations. Current vibration damping systems can effectively isolate the effects of high-frequency vibrations, but cannot effectively isolate the effects of low-frequency vibrations.

[0004] During flight, aircraft are affected by various low-frequency vibration sources, such as elastic deformation of the aircraft body, low-frequency vibration of the engine, and low-frequency excitation of aerodynamic forces. These low-frequency vibrations are transmitted to the inertial navigation equipment, causing a significant decrease in the accuracy of the measurement parameters of the inertial navigation equipment, which in turn affects the control accuracy of the flight control system, leading to instability in the aircraft's attitude control, and in severe cases, endangering flight safety.

[0005] Currently, the main approach is to increase the rigidity of the mounting structure and raise the mounting frequency to isolate the impact of low-frequency vibrations on the aircraft's inertial navigation equipment. However, this technical solution would significantly increase the weight of the mounting structure, which does not meet the current requirements for aircraft weight reduction. Therefore, this application is hereby submitted. Summary of the Invention

[0006] This application addresses the conflict between the design weight and natural frequency of the installation structure for aircraft inertial navigation equipment by providing a design method for the installation structure of aircraft inertial navigation equipment. This method achieves lightweight design of the installation structure while meeting the installation frequency requirements of the inertial navigation equipment, and can efficiently design an installation structure that meets the requirements for low-frequency vibration isolation and effectively controls the weight.

[0007] The technical solution of this application is:

[0008] A method for designing an installation structure for an aircraft inertial navigation system, comprising:

[0009] Step 1: Based on the overall vibration characteristics of the machine, select an area with a small vibration response as the installation area for the inertial navigation equipment;

[0010] Step 2: Using regular models, design the installation structure of the inertial navigation equipment and establish a dynamic finite element model of the installation structure of the inertial navigation equipment and related structures in its installation area.

[0011] Step 3: Based on the dynamic finite element model of the inertial navigation equipment installation structure and related structures in its installation area, perform modal analysis to obtain the main frequencies of the inertial navigation equipment installation structure, and ensure that the first natural frequency of the inertial navigation equipment installation structure is greater than the design frequency value.

[0012] Step 4: Perform topology optimization on the inertial navigation equipment installation structure. The optimization goal is to minimize the weight while ensuring that the first natural frequency of the inertial navigation equipment installation structure is greater than the design frequency value.

[0013] Step 5: Consider the feasibility of the manufacturing process and conduct a preliminary design of the installation structure for the inertial navigation equipment;

[0014] Step 6: In the dynamic finite element model of the inertial navigation equipment installation structure and its related structures in the installation area, update the inertial navigation equipment installation structure, and then optimize the size of the inertial navigation equipment installation structure. The optimization goal is to minimize the weight, while ensuring that the first natural frequency of the inertial navigation equipment installation structure is greater than the design frequency value.

[0015] Step 7: Conduct a detailed design of the inertial navigation equipment installation structure, and perform modal analysis based on the dynamic finite element model of the inertial navigation equipment installation structure and related structures in its installation area to ensure that the first natural frequency of the inertial navigation equipment installation structure is greater than the design frequency value.

[0016] Optionally, the above-mentioned design method for the installation structure of aircraft inertial navigation equipment also includes:

[0017] Step 8: Process and manufacture the inertial navigation equipment installation structure, and conduct ground frequency testing to ensure that the first natural frequency of the inertial navigation equipment installation structure is greater than the design frequency value.

[0018] Optionally, in the above-mentioned design method for the installation structure of aircraft inertial navigation equipment, the design frequency value is 180Hz;

[0019] The installation structure of inertial navigation equipment mainly includes an inertial navigation installation platform and an inertial navigation installation stand.

[0020] Optionally, in the above-mentioned aircraft inertial navigation equipment installation structure design method, in step one, the forefuselage area is used as the installation area for the inertial navigation equipment, and the inertial navigation equipment is arranged near the main load-bearing frame.

[0021] Optionally, in the above-mentioned design method for the installation structure of aircraft inertial navigation equipment, when establishing the dynamic finite element model of the inertial navigation equipment installation structure and related structures in its installation area in step two, solid elements are used for the inertial navigation installation platform and the inertial navigation installation stand.

[0022] Optionally, in the above-mentioned design method for the installation structure of aircraft inertial navigation equipment, in step six, a finite element dynamic model of the inertial navigation installation platform and the inertial navigation installation stand is established using shell elements, and then replaced in the finite element dynamic model of the inertial navigation equipment installation structure and related structures in its installation area. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the aircraft inertial navigation equipment installation structure design method provided in the embodiments of this application;

[0024] Figure 2 This is a schematic diagram showing the cooperation between the inertial navigation device installation structure and related structures in the installation area provided in the embodiments of this application;

[0025] Figure 3 yes Figure 2 A partial schematic diagram;

[0026] in:

[0027] 1-Inner wall panel; 2-Outer wall panel; 3-Skin; 4-First load-bearing frame; 5-Second load-bearing frame; 6-Reinforcing rib; 7-Airborne equipment; 8-Airborne equipment installation structure; 9-Inertial navigation equipment; 10-Inertial navigation installation platform; 11-Inertial navigation installation upright plate.

[0028] To better illustrate this embodiment, some content in the accompanying drawings may be omitted, enlarged, or reduced. They are for illustrative purposes only and should not be construed as limiting the scope of this application. Detailed Implementation

[0029] To make the technical solution and advantages of this application clearer, the technical solution of this application will be described in a clearer and more complete manner below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some 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 related to this application are shown in the accompanying drawings, and other related parts can be referred to the general design.

[0030] Furthermore, unless otherwise defined, the technical or scientific terms used in this application description shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The word "comprising" as used in this application description indicates that the concept preceding the word encompasses the concepts listed following the word and their equivalents, without excluding other related concepts.

[0031] Furthermore, the terms indicating location 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. It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation" and "connection" used in the description of this application should be interpreted broadly. For example, a 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. Those skilled in the art can understand its specific meaning in this application according to the specific circumstances.

[0032] A design method for the installation structure of an aircraft inertial navigation device, such as Figure 1 As shown, by optimizing the onboard layout of the inertial navigation equipment and combining it with the multi-objective optimization design of the installation structure, the lightweight installation structure is achieved while meeting the requirements for low-frequency vibration isolation.

[0033] Step 1: Based on the overall vibration characteristics of the machine, select an area with a small vibration response as the installation area for the inertial navigation equipment.

[0034] The vibration characteristics of the entire machine can be obtained through structural simulation.

[0035] In aircraft structures, the forward fuselage is far from the main vibration sources and has lower vibration response characteristics, making it a preferred location for inertial navigation equipment (INS) installation. Furthermore, the INS can be positioned near the main load-bearing frame to increase the support stiffness of the INS installation structure, thereby effectively reducing energy transfer along the vibration transmission path.

[0036] Step 2: Using regular models, design the installation structure of the inertial navigation equipment and establish a dynamic finite element model of the installation structure of the inertial navigation equipment and related structures in the installation area.

[0037] The inertial navigation equipment installation structure mainly includes an inertial navigation installation platform 10 and an inertial navigation installation stand 11. The inertial navigation installation stand 11 supports the inertial navigation installation platform 10 on the body structure, and the inertial navigation equipment 9 is installed on the inertial navigation installation platform 10.

[0038] To avoid the influence of the stiffness of auxiliary equipment and boundary supports on the calculation results, the layout and connection method of the inertial navigation equipment installation structure and related structures must be considered when establishing the dynamic finite model. In a specific example, the coordination between the inertial navigation equipment installation structure and related structures in the installation area is as follows: Figure 2As shown, the principle for establishing the dynamic finite model is as follows: the inner wall panel 1, the outer wall panel 2, the skin 3, the first load-bearing frame 4, and the second load-bearing frame 5 are shell elements; the reinforcing ribs 6 are beam elements; the airborne equipment 7 is a mass point element; the airborne equipment installation structure 8 is a shell element; the inertial navigation equipment 9 is a mass point element; and the inertial navigation installation platform 10 and the inertial navigation installation upright plate 11 are solid elements.

[0039] Step 3: Based on the dynamic finite element model of the inertial navigation equipment installation structure and related structures in its installation area, perform modal analysis to obtain the main frequencies of the inertial navigation equipment installation structure, and ensure that the first natural frequency of the inertial navigation equipment installation structure is greater than the design frequency value.

[0040] Modal analysis was performed using finite element software. Boundary conditions were defined appropriately during the analysis process, and the influence of the number of meshes on the analysis results was verified in order to obtain the accurate main frequencies of the inertial navigation equipment installation structure.

[0041] Step 4: Perform topology optimization on the inertial navigation equipment installation structure. The optimization goal is to minimize the weight while ensuring that the first natural frequency of the inertial navigation equipment installation structure is greater than the design frequency value.

[0042] Through topology optimization, the forms of the inertial navigation installation platform 10 and the inertial navigation installation stand 11 can be preliminarily determined, providing a basis for the preliminary design of the subsequent inertial navigation equipment installation structure.

[0043] Step 5: Consider the feasibility of the manufacturing process and conduct a preliminary design of the installation structure for the inertial navigation equipment.

[0044] Based on the topology optimization results, a preliminary design was carried out for the inertial navigation installation platform 10 and the inertial navigation installation stand 11. During the design process, the feasibility of the manufacturing process was fully considered to ensure that it can be transformed into practical engineering applications.

[0045] Step 6: In the dynamic finite element model of the inertial navigation equipment installation structure and its related structures in the installation area, update the inertial navigation equipment installation structure, and then optimize the dimensions of the inertial navigation equipment installation structure. The optimization objective is to minimize the weight, while ensuring that the first natural frequency of the inertial navigation equipment installation structure is greater than the design frequency value.

[0046] A finite element dynamic model of the inertial navigation installation platform 10 and the inertial navigation installation plate 11 is established using shell elements, and then replaced in the finite element dynamic model of the inertial navigation equipment installation structure and related structures in the installation area.

[0047] Step 7: Conduct a detailed design of the inertial navigation equipment installation structure, and perform modal analysis based on the dynamic finite element model of the inertial navigation equipment installation structure and related structures in its installation area to ensure that the first natural frequency of the inertial navigation equipment installation structure is greater than the design frequency value.

[0048] Step 8: Process and manufacture the inertial navigation equipment installation structure, and conduct ground frequency testing to ensure that the first natural frequency of the inertial navigation equipment installation structure is greater than the design frequency value.

[0049] In a specific example, the inertial navigation device weighs 15kg. The front fuselage area is selected as the installation area for the inertial navigation device. Using a regular body, a scheme design is carried out for the installation structure of the inertial navigation device. A dynamic finite element model of the installation structure and related structures in the installation area is established, and modal analysis is performed to ensure that the first natural frequency of the installation structure is greater than the design frequency value of 180Hz. Topology optimization is performed on the installation structure, and a preliminary design of the installation structure is carried out. Then, the dimensions of the installation structure are optimized. Based on the results of the dimension optimization, a detailed design of the installation structure is carried out, and modal analysis is performed to ensure that the first natural frequency of the installation structure is greater than the design frequency value of 180Hz. After the installation structure is manufactured and installed, ground frequency testing is conducted to ultimately ensure that its first natural frequency is greater than the design frequency value of 180Hz.

[0050] The technical solution of this 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 this application is obviously not limited to these specific embodiments. Without departing from the principles of this 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 all fall within the scope of protection of this application.

Claims

1. A design method for the installation structure of an aircraft inertial navigation device, characterized in that, include: Step 1: Based on the overall vibration characteristics of the machine, select an area with a small vibration response as the installation area for the inertial navigation equipment; Step 2: Using regular models, design the installation structure of the inertial navigation equipment and establish a dynamic finite element model of the installation structure of the inertial navigation equipment and related structures in its installation area. Step 3: Based on the dynamic finite element model of the inertial navigation equipment installation structure and related structures in its installation area, perform modal analysis to obtain the main frequencies of the inertial navigation equipment installation structure, and ensure that the first natural frequency of the inertial navigation equipment installation structure is greater than the design frequency value. Step 4: Perform topology optimization on the inertial navigation equipment installation structure. The optimization goal is to minimize the weight while ensuring that the first natural frequency of the inertial navigation equipment installation structure is greater than the design frequency value. Step 5: Consider the feasibility of the manufacturing process and conduct a preliminary design of the installation structure for the inertial navigation equipment; Step 6: In the dynamic finite element model of the inertial navigation equipment installation structure and its related structures in the installation area, update the inertial navigation equipment installation structure, and then optimize the size of the inertial navigation equipment installation structure. The optimization goal is to minimize the weight, while ensuring that the first natural frequency of the inertial navigation equipment installation structure is greater than the design frequency value. Step 7: Conduct a detailed design of the inertial navigation equipment installation structure, and perform modal analysis based on the dynamic finite element model of the inertial navigation equipment installation structure and related structures in its installation area to ensure that the first natural frequency of the inertial navigation equipment installation structure is greater than the design frequency value.

2. The aircraft inertial navigation equipment installation structure design method according to claim 1, characterized in that, Also includes: Step 8: Process and manufacture the inertial navigation equipment installation structure, and conduct ground frequency testing to ensure that the first natural frequency of the inertial navigation equipment installation structure is greater than the design frequency value.

3. The aircraft inertial navigation equipment installation structure design method according to claim 2, characterized in that, The designed frequency is 180Hz; The inertial navigation equipment installation structure mainly includes an inertial navigation installation platform (10) and an inertial navigation installation stand (11).

4. The aircraft inertial navigation equipment installation structure design method according to claim 3, characterized in that, In step one, the front fuselage area is used as the installation area for the inertial navigation equipment, and the inertial navigation equipment is placed near the main load-bearing frame.

5. The aircraft inertial navigation equipment installation structure design method according to claim 4, characterized in that, In step two, when establishing the dynamic finite element model of the inertial navigation equipment installation structure and related structures in its installation area, solid elements are used for the inertial navigation installation platform (10) and the inertial navigation installation plate (11).

6. The aircraft inertial navigation equipment installation structure design method according to claim 5, characterized in that, In step six, a finite element model of the inertial navigation installation platform (10) and the inertial navigation installation stand (11) is established using shell elements, and then replaced in the finite element model of the inertial navigation equipment installation structure and related structures in its installation area.

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