Helicopter transmission system digital engineering overall technology analysis method

Abstract

The invention discloses a helicopter transmission system digital engineering overall technology analysis method, and relates to the field of helicopter transmission system digital engineering, and the method comprises the steps: building a helicopter transmission system overall design digital environment; demand capturing is carried out around all benefit critical people and facing scenes; obtaining preliminary design requirements, node parameters, interface requirements and overall requirements of the helicopter transmission system; carrying out helicopter transmission system-component-part demand analysis, and establishing a demand model, a function model, a logic model and a physical model; establishing a design model, a manufacturing model, an assembly model and a test model; and establishing a comprehensive database, and storing the model established in each stage into the comprehensive database to realize numerical model multiplexing and complete digital design closed loop. The problems that a traditional analysis method is low in efficiency, low in integration level, short in simulation evaluation and long in closed loop iteration period are solved.

Description

Technical Field

[0001] The present invention relates to the field of helicopter transmission system digital engineering, and in particular to an analysis method for the overall technology of helicopter transmission system digital engineering. Background Art

[0002] Digital engineering is an integrated digital approach that leverages authoritative model and data sources across the system lifecycle to support all system activities, from concept development to end-of-life disposal. The transmission system, as one of the three major moving parts of a helicopter (engine, rotor system, and transmission), plays a crucial role in its performance, efficiency, flight safety, and advancement, integrating cutting-edge technologies from many aerospace fields. Compared to other mechanical transmission systems, helicopter transmission systems are complex, involve a wide range of disciplines, undergo numerous design iterations, have long finalization cycles, and exhibit high R&D risks. Traditional R&D models suffer from low development efficiency, a lack of model descriptions across disciplines / systems, low levels of multidisciplinary integration, a lack of simulation and evaluation tools, and long closed-loop design iteration cycles, making it difficult to meet user requirements for quality, cost, and cycle time. Therefore, adopting digital methods to establish data transfer and interactive iteration for models of helicopter transmission system design, manufacturing, assembly, and testing digital prototypes can systematically improve work efficiency, enhance R&D effectiveness, increase development benefits, improve scientific and technological foundations, ensure product delivery quality, highlight the overall advantages of digitalization, and meet user needs for digital transformation. Driven by the wave of digital development, digital transformation in China's industrial sector is a comprehensive and in-depth process. National policies have established a top-level design framework for digital projects, making overall arrangements to enhance their integrity, systematicness, and synergy. After years of transformation and upgrades, my country's digital projects have grown from nothing to a substantial entity. Digital projects are becoming a key means of coping with uncertainty, mitigating risks, reducing costs, improving quality, and increasing efficiency, and reshaping organizational capabilities.

[0003] Digital engineering is an integrated digital approach that leverages authoritative model and data sources for a system, providing models and data that can be continuously transferred across disciplines and domains throughout its lifecycle, supporting all system activities from concept development to disposal. The core of digital engineering is the creation of digital models that define and describe all aspects of the system and support all design, development, manufacturing, and operation activities throughout the system's lifecycle. Traditional document-based design approaches suffer from low system development efficiency, a lack of model descriptions across disciplines / systems, low multi-disciplinary integration, a lack of simulation and evaluation tools, and long closed-loop design iteration cycles. This is particularly true for helicopter coaxial counter-rotating transmission systems, whose high-power input stage, high-power tail thruster, and coaxial counter-rotating structure present new design challenges. Overall, the transmission system design requirements require multiple iterations, resulting in a long design finalization cycle. Digital approaches are urgently needed to establish a digital prototype of the helicopter transmission system, seamlessly integrating the design-manufacturing-assembly-testing process, standardizing the definition and flow of the transmission system digital model, enabling demand-driven design and seamless data integration throughout the R&D process, and reducing design iterations. Summary of the Invention

[0004] In response to the above-mentioned deficiencies in the prior art, the present invention provides an analysis method for the overall technology of digital engineering of helicopter transmission systems, which solves the problems of low efficiency, low integration, lack of simulation evaluation, and long closed-loop iteration cycle of traditional analysis methods.

[0005] In order to achieve the above-mentioned object, the technical solution adopted by the present invention is: an analysis method of the overall technology of digital engineering of helicopter transmission system, comprising the following steps: S1: Build a digital environment for the overall design of helicopter transmission systems; S2: Based on the established digital environment for helicopter transmission system overall design, requirements are captured for all stakeholders and scenarios. S3: Based on demand capture, obtain the preliminary design requirements, node parameters, interface requirements and overall requirements of the helicopter transmission system; S4: Based on preliminary design requirements, node parameters, interface requirements and overall requirements, conduct helicopter transmission system-component-parts requirements analysis and establish requirements model, functional model, logical model and physical model; S5: Establish design model, manufacturing model, assembly model and test model; S6: Establish a comprehensive database and store the models established in each stage in the comprehensive database to achieve numerical model reuse and complete the digital design closed loop.

[0006] Furthermore, the digital environment for the overall design of the helicopter transmission system in S1 includes a client, a functional layer, a core service layer, a data support layer, a database, and an application server; The client, database, and application server all include an integrated platform system typified by a model and data platform, as well as various tool software that support all technical and management activities throughout the entire life cycle, including simulation and analysis software, design and modeling software, data acquisition and analysis software, and engineering management software; The functional layer realizes end-to-end connection from demand to delivery and use in the time dimension, and realizes the connection between the physical and virtual worlds in the spatial dimension; The core service layer is oriented towards the entire life cycle of the helicopter transmission system, with digital clues based on models and data as the core, using the overall requirements of the helicopter transmission system digital engineering, including demand definition and modeling services, indicator system construction services, unification and coordination services, heterogeneous system association services and data visualization customization services; The data support layer includes a continuous and consistent model system and data, including: engineering standards, demand data, design data, simulation data, manufacturing data, assembly data and test data. The data model and business rules are sorted out in the data support layer, and logical associations and multi-view mapping rules between various types of data are established.

[0007] Furthermore, in S2, requirements are captured around all stakeholders and in a scenario-oriented manner, including the following steps: S21: Conduct context analysis on the helicopter transmission system to obtain the connection mode and material exchange form of each system with the helicopter transmission system. The systems connected with the helicopter transmission system include the fuselage system, power system, rotor system, avionics system, fuel supply system, control system and lubricating oil system. S22: Define the operational scenarios of the helicopter transmission system. Based on the overall helicopter design requirements, propose transmission system requirements for the operational scenarios for all stakeholders. Use DOORS or tools that support the SysML language to digitally capture, characterize, and define relationships for the helicopter transmission system requirements. S23: Establish initial requirements for the helicopter transmission system. The initial requirements are in the form of text documents or requirements managed in DOORS.

[0008] Furthermore, the preliminary design requirements, node parameters, interface requirements and overall requirements of the helicopter transmission system in S3 include: Overall layout requirements: The overall layout requirements include weight, size, main reduction interface, tail reduction interface and skeleton model; Performance index requirements: The performance index requirements include power, transmission efficiency, weight, dry running, ballistic resistance, strength, compensation capability, vibration and noise; Functional requirements: These functional requirements include speed steering, power transmission, steering matching, lubrication and cooling, accessory transmission, and working mode switching; General quality characteristics and standardization requirements: The general quality characteristics and standardization requirements include reliability, maintainability, security, testability, safety and environmental adaptability.

[0009] Furthermore, the demand model in S4 is represented by structured text using a modeling tool to sort out stakeholders and complete the capture of top-level task requirements; with the refinement of the model, a decomposition of top-level requirements to system requirements, system requirements to subsystem requirements, and subsystem requirements to component requirements is formed; and demand traceability analysis and satisfaction verification are achieved; The functional model is structured using the SysML language to describe functional goals and conduct functional black box analysis based on use cases; it also describes interface relationships and establishes a traceable relationship between requirements and functions. The logical model adopts SysML language to form a logical model of the transmission system according to the assigned functions, which is used for logical structure representation, function allocation of each level of the system, parameter index allocation, interface design and parameter definition; The physical model is based on CATIA to complete the three-dimensional structure construction of the helicopter transmission system, carry out data transmission interface and analysis research between various models, and complete the digital description of each model data.

[0010] Furthermore, the method for establishing the design model, manufacturing model, assembly model and test model in S5 is: Design model: It consists of requirements assigned to the design phase, design parameter text, and ANSYS and ABAQUS simulation tools for single-discipline performance and multi-discipline joint simulation of the transmission system; Manufacturing model: It is composed of the requirements assigned to the manufacturing stage, manufacturing process text data, manufacturing process inspection data, and manufacturing process simulation model; Assembly model: It consists of requirements assigned to the assembly stage, assembly process design, assembly process data analysis and collection, assembly process structure and process visualization model; Test model: It is composed of the requirements assigned to the test phase, test results, and measurement point information models.

[0011] Furthermore, the comprehensive database is established in S6, specifically: For structured data, the relational database MySQL is used for storage; For semi-structured data, it is stored in the relational database MySQL in the form of file streams; For unstructured data, MinIO is used to manage large files, and the storage indexes in MinIO are stored in the relational database MySQL.

[0012] Furthermore, the models established in each stage are stored in the comprehensive database in S6. Specifically, the demand model, functional model, logical model, physical model, design model, manufacturing model, assembly model and test model are saved in the comprehensive database through XML and JSON interfaces to realize closed-loop iteration of requirements and indicators and full-process data monitoring.

[0013] The beneficial effects of the present invention are as follows: The overall helicopter transmission system digital engineering technology utilizes digital technology, guided by the overall requirements of helicopter transmission system digital engineering, and targets key helicopter transmission components (such as input cylindrical gears, coaxial herringbone gears, and parallel arc gears). Based on digital models and a data indicator system, the technology structuredly defines and represents transmission system entities (design models, manufacturing models, assembly models, and test models), as well as standards, empirical knowledge, and business processes during the design and development process, in a high-performance virtual reality (digital space) environment. This technology achieves a digital representation of entities, processes, knowledge, and business processes that can be computer-recognized, processed, analyzed, applied, and traced. A business flow and management engine for the entire helicopter transmission system development process is developed. Through transmission system development requirements analysis, definition, and decomposition, it clarifies the requirements driving each stage of transmission system development, enabling demand-driven integrated management of transmission system design, manufacturing, assembly, and testing data and processes. This technology enables closed-loop verification and iteration of requirements and indicators, full-process data monitoring, and full-lifecycle model reuse, supporting real-time interaction, collaboration, and quantitative decision-making among all stakeholders. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a flow chart of the analysis method for the overall technology of digital engineering of a helicopter transmission system.

[0015] Figure 2 This is the overall design environment architecture diagram for the digital engineering of the helicopter transmission system.

[0016] Figure 3 Contextual analysis diagram for the helicopter transmission system.

[0017] Figure 4 Schematic diagram of the overall technical platform of the transmission system.

[0018] Figure 5 This is a diagram of the platform's data storage technology architecture.

[0019] Figure 6 This is a schematic diagram of a parameter baseline and parameter version.

[0020] Figure 7 This is the structural diagram of the physical model of the helicopter transmission system. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0022] like Figure 1 As shown, a method for analyzing the overall technology of digital engineering of a helicopter transmission system includes the following steps: S1: Build a digital environment for the overall design of helicopter transmission systems; S2: Based on the established digital environment for helicopter transmission system overall design, requirements are captured for all stakeholders and scenarios. S3: Based on demand capture, obtain the preliminary design requirements, node parameters, interface requirements and overall requirements of the helicopter transmission system; S4: Based on preliminary design requirements, node parameters, interface requirements and overall requirements, conduct helicopter transmission system-component-parts requirements analysis and establish requirements model, functional model, logical model and physical model; S5: Establish design model, manufacturing model, assembly model and test model; S6: Establish a comprehensive database and store the models established in each stage in the comprehensive database to achieve numerical model reuse and complete the digital design closed loop.

[0023] like Figure 2 As shown, the digital environment for the overall design of the helicopter transmission system in S1 includes a client, a functional layer, a core service layer, a data support layer, a database, and an application server; The client, database, and application server all include an integrated platform system typified by a model and data platform, as well as various tool software that support all technical and management activities throughout the entire life cycle, including simulation and analysis software, design and modeling software, data acquisition and analysis software, and engineering management software; The functional layer realizes end-to-end connection from demand to delivery and use in the time dimension, and realizes the connection between the physical and virtual worlds in the spatial dimension; The core service layer is oriented towards the entire life cycle of the helicopter transmission system, with digital clues based on models and data as the core, using the overall requirements of the helicopter transmission system digital engineering, including demand definition and modeling services, indicator system construction services, unification and coordination services, heterogeneous system association services and data visualization customization services; The data support layer includes a continuous and consistent model system and data, including: engineering standards, demand data, design data, simulation data, manufacturing data, assembly data and test data. The data model and business rules are sorted out in the data support layer, and logical associations and multi-view mapping rules between various types of data are established.

[0024] The underlying framework for the helicopter transmission system's digital support consists of a database, a file repository, and an application server. The helicopter design and development process generates not only a large amount of structured data but also a significant amount of unstructured data. Relational databases use a relational model to organize data, with a fixed table header structure, making them suitable for storing structured data. Furthermore, data in relational databases is stored securely and reliably on disk. Non-relational databases lack a fixed structured table header structure and are therefore suitable for storing unstructured data, including formats such as documents and images. Given the need for transactional support, the open-source MySQL database was selected. Furthermore, the platform needed to support real-time message push and multi-user collaboration, so the open-source in-memory database Redis was chosen as the cache database. For file storage, the Java-based open-source library MinIO was selected to support distributed storage of large files to accommodate the rapid growth in file size. Tomcat, an open-source application server from the Apache Foundation, was chosen as the application server. Tomcat is a dynamic server and its support for static resources such as HTML pages and images is not as good as NGINX. In addition, NGINX also has gateway, load balancing and reverse proxy functions. Therefore, the open source NGINX server is selected to provide static resource support and load balancing and reverse proxy functions.

[0025] The data support layer encompasses various multi-domain, multi-disciplinary, and multi-resolution professional models and data generated throughout the helicopter lifecycle development process, including requirements models, multi-resolution simulation models, optimization and evaluation algorithms, and R&D data. This supports the establishment of a collaborative design context, as well as capabilities such as model data change configuration management, model sedimentation, and model reuse. Data interaction with the design data management module occurs at all stages of the helicopter transmission system digital engineering process. The data support layer must consider the diverse data types, massive data volumes, frequent data interactions, and real-time data preservation. The data support layer organizes data models and business rules, establishes logical relationships between various data types, and establishes multi-view mapping rules to ensure a single source of truth, a single source of truth, and organic connections throughout the lifecycle. Requirements models include mission models, functional models, architecture models, indicator and margin models, and multi-resolution simulation models. Multi-domain models, proxy models, heterogeneous models, and external programs are included in the multi-resolution simulation model. Optimization and evaluation algorithms include experimental design algorithms, parameter identification algorithms, optimization methods, and evaluation algorithms. R&D data includes system models, test data, simulation data, and document reports. These multi-domain, multi-resolution, and multi-professional models and data are brought together to form a unified data source model.

[0026] The core service layer is oriented towards the entire life cycle of the helicopter transmission system, with digital clues (digital main line) based on models and data as the core, using the overall requirements of the helicopter transmission system digital engineering, including core services such as demand definition and modeling, indicator system construction, unification and coordination, heterogeneous system association, and data visualization customization. The data support and functional layers are the core vehicles for implementing activities throughout the helicopter transmission system's lifecycle. Data support includes a consistent model system and data, covering lifecycle stages such as standards, requirements, design, simulation, manufacturing, assembly, and testing, and encompassing the helicopter transmission system's system-level, components, and parts. The hierarchical functional layer provides end-to-end connectivity from requirements to delivery in the temporal dimension, and connects the physical and virtual worlds in the spatial dimension, thereby driving the definition of model data, the trusted environment for platform tools, and foundational support.

[0027] Clients, databases, and application servers provide the necessary basic conditions and guarantees for the implementation of business activities throughout the entire life cycle, including integrated platform systems and various tool software that have been fully verified and adopted, integrated platform systems (data centers) represented by models and data platforms, and various tool software that support all technical and management activities throughout the entire life cycle (simulation and analysis software, design and modeling software, data acquisition and analysis software, engineering management software, etc.).

[0028] An overall platform for digital engineering of helicopter transmission systems was established. The platform integrated and encapsulated the functional units provided by third-party tools, such as the requirements modeling collaboration tool, SysML modeling tool, collaborative design modeling tool, and collaborative design simulation tool based on multi-resolution models, making them process components and responsible for maintaining the unified data source model for the entire helicopter life cycle. The process engine calls the process component, which is essentially calling a single functional unit. After completing the modeling / simulation through the functional unit, all output result files are stored in the database. During the initialization phase of the unified data source model for the entire helicopter life cycle, the platform reads the requirements model and the multi-resolution and multi-discipline models from the requirements modeling collaboration tool and the collaborative design simulation tool based on multi-resolution models through interface calls to construct the unified data source model.

[0029] S2 involves capturing requirements from all stakeholders and scenarios, and includes the following steps: S21: Conduct context analysis on the helicopter transmission system to obtain the connection mode and material exchange form of each system with the helicopter transmission system. The systems connected with the helicopter transmission system include the fuselage system, power system, rotor system, avionics system, fuel supply system, control system and lubricating oil system. S22: Define the operational scenarios of the helicopter transmission system. Based on the overall helicopter design requirements, propose transmission system requirements for the operational scenarios for all stakeholders. Use DOORS or tools that support the SysML language to digitally capture, characterize, and define relationships for the helicopter transmission system requirements. S23: Establish initial requirements for the helicopter transmission system. The initial requirements are in the form of text documents or requirements managed in DOORS.

[0030] To capture helicopter transmission system requirements, we first identify stakeholders and conduct a contextual analysis of the helicopter transmission system, clarifying how each system connects to the helicopter transmission system and how material exchanges occur. The systems that interact with the helicopter transmission system include the airframe, powertrain, rotor system, avionics system, fuel supply system, control system, and lubricating oil system. Once the relevant systems are identified, requirements collection should focus not only on transmission system requirements but also on the requirements of these other systems for the helicopter transmission system, based on the material exchanges between these systems. Figure 3 Contextual analysis for helicopter transmission systems.

[0031] Next, operational scenarios are defined. These encompass the design personnel, flight missions, internal and external environments, and the transmission system's internal conditions. Each scenario defines a system use case. Based on the overall helicopter design requirements, transmission system requirements are formulated for these operational scenarios, encompassing all stakeholders. Incorporating requirements from GJB2350, GJB720, CCAR-29, and the Helicopter Transmission System Design Manual and Specifications (power and torque, accessory requirements, interface requirements, high-power main reducer / tail thrust reducer lubrication requirements, general quality characteristics, operating environment requirements, speed steering, state switching, high-power tail thrust clutch, power and load spectrum, efficiency, weight, etc.), overall transmission system requirements are identified and itemized. DOORS or tools supporting SysML are used to digitally capture, characterize, and define relationships within these requirements.

[0032] Then, the initial requirements for the helicopter transmission system are established. The initial requirements are generally text documents or requirements managed in DOORS. These requirements have poor correlation. To facilitate understanding and data flow throughout the digitalization cycle, these requirements with poor correlation are established as SysML requirement diagrams to obtain requirements in terms of overall requirements, basic performance, survivability, availability, lifespan, and common quality characteristics.

[0033] The preliminary design requirements, node parameters, interface requirements and overall requirements of the helicopter transmission system in S3 include: Overall layout requirements: The overall layout requirements include weight, size, main reduction interface, tail reduction interface and skeleton model; Weight and size are determined by configuration, materials, etc. The main and tail reduction interfaces are determined by the configuration and overall requirements of the helicopter. The helicopter has requirements for the installation position, installation form and overall dimensions of the transmission system on the helicopter platform.

[0034] Performance index requirements: The performance index requirements include power, transmission efficiency, weight, dry running, ballistic resistance, strength, compensation capability, vibration and noise; Power and speed are related to platform-engine requirements and transmission configuration; transmission efficiency is related to configuration, lubrication, etc.

[0035] Functional requirements: These functional requirements include speed steering, power transmission, steering matching, lubrication and cooling, accessory transmission, and working mode switching; A helicopter should have functions that meet the needs of use. For example, the helicopter can perform speed steering in the air and transfer the engine power to the rotor and tail rotor. Accessory transmission refers to transferring part of the engine power to accessories, such as lighting systems, lubrication systems, hydraulic systems, etc., to ensure the normal operation of other systems of the helicopter.

[0036] General quality characteristics and standardization requirements: The general quality characteristics and standardization requirements include reliability, maintainability, security, testability, safety and environmental adaptability.

[0037] General quality characteristics are related to configuration, usage conditions, component design, strength, and lubrication.

[0038] In addition to the aforementioned requirements, helicopter transmission system requirements also include relevant national laws, policies, design specifications, and military standards. These requirements encompass not only stakeholder needs but also relevant experimental indicators after the design is completed, such as ground bench testing and test intervals. Obtain helicopter transmission system requirements, refine these requirements based on helicopter operational scenarios, map scenarios to requirements, and establish initial requirements for the helicopter transmission system. A qualitative approach, combined with quantitative methods as appropriate, will be used to establish a requirements correlation matrix.

[0039] Qualitative methods primarily draw on existing requirements mapping relationships both domestically and internationally. This approach derives requirements for basic helicopter mission types that incorporate historical experience and meet regulatory requirements. Quantitative methods, primarily based on empirical or statistical data, use dimensional analysis to provide logical relationships between transmission system requirements and between system requirements and subsystem requirements. For example, the power-to-weight ratio of the entire aircraft can be used to derive power and weight. Power, in turn, relates to a series of subsystem requirements, including configuration and speed reducer requirements. Weight can be broken down into the weight of each component.

[0040] The requirement model in S4 is represented by structured text using modeling tools to sort out stakeholders and capture top-level task requirements. Model refinement is used to decompose top-level requirements into system requirements, system requirements into subsystem requirements, and subsystem requirements into component requirements. This allows for demand traceability analysis and satisfaction verification. The functional model is structured using the SysML language to describe functional goals and conduct functional black box analysis based on use cases; it also describes interface relationships and establishes a traceable relationship between requirements and functions. Using SysML language, a logical model of the transmission system is formed according to the assigned functions, which is used for logical structure representation, function allocation at each level of the system, parameter index allocation, interface design and parameter definition; The physical model is based on CATIA to complete the three-dimensional structure construction of the helicopter transmission system, carry out data transmission interface and analysis research between various models, and complete the digital description of each model data.

[0041] Demand analysis runs through the entire life cycle of the helicopter transmission system. The helicopter transmission system demand analysis gradually refines the transmission system requirements according to the "system-components-parts" through the processes of transmission system demand identification, functional analysis, demand modeling, and demand association relationship establishment. With the help of demand modeling and management software, a hierarchical and structured demand model of the helicopter transmission system is finally obtained.

[0042] Using relationships like derive and copy, helicopter transmission system requirements (such as overall layout, functionality, performance indicators, common quality characteristics, and standardization) are constructed, establishing requirements traceability and verification. When a requirement changes, requirement traceability allows for automated impact analysis, saving significant time and costs. The figure shows a helicopter transmission system requirements model (based on SysML).

[0043] On this basis, physical models (CATIA) and performance models (MATLAB, ANSYS, ABAQUS, ADAMS, etc.) are constructed. First, the requirements model is constructed by importing the transmission system usage requirements (power and torque, speed and steering, load, accessory requirements, efficiency, vibration, survivability, weight, life, general quality characteristics, etc.), including functional requirements, non-functional requirements, and design constraints. Second, functional analysis is conducted based on the requirements model, and the system functional structure (logical architecture) is derived through behavioral diagrams. A preliminary decomposition of requirements and solution trade-offs are then performed. Third, the physical model of the helicopter transmission system is designed based on the logical architecture, and a mapping relationship between the requirements and the physical model is established. Fourth, the transmission system simulation of the physical model is conducted to verify the feasibility of the solution and optimize the performance indicators.

[0044] The method for establishing the design model, manufacturing model, assembly model and test model in S5 is: Design model: It consists of requirements assigned to the design phase, design parameter text, and ANSYS and ABAQUS simulation tools for single-discipline performance and multi-discipline joint simulation of the transmission system; Manufacturing model: It is composed of the requirements assigned to the manufacturing stage, manufacturing process text data, manufacturing process inspection data, and manufacturing process simulation model; Assembly model: It consists of requirements assigned to the assembly stage, assembly process design, assembly process data analysis and collection, assembly process structure and process visualization model; Test model: It is composed of the requirements assigned to the test phase, test results, and measurement point information models.

[0045] S5 establishes design, manufacturing, assembly, and test models: Metamodel-based transmission system data representation and definition abstracts the transmission system requirements model, component design parameters, manufacturing parameters, assembly parameters, and performance / test result parameters from different stages, such as requirements, design, manufacturing, assembly, and testing. These models are then defined in XML and JSON file formats. By constructing the requirements metamodel, design metamodel, manufacturing metamodel, assembly metamodel, and test metamodel, the requirements model is integrated with heterogeneous models from various R&D stages, reducing the overall database data capacity and enabling metamodel-centric data management and transmission, providing a basis for subsequent data traceability throughout the entire process.

[0046] like Figure 4 As shown in the figure, the overall technical platform of the transmission system (project id, creator, creation time, modification time, design prototype model id, manufacturing prototype model id, assembly prototype model id, test prototype model id, requirement model id, requirement model creation time, requirement model modification time, indicator id, solution id, model id, result metamodel id) manages the digital "design-manufacturing-assembly-test" full process data, with project id as the primary key and design prototype model id, manufacturing prototype model id, assembly prototype model id, test prototype model id, requirement model id and result metamodel id as foreign keys.

[0047] Design prototype (design prototype ID, number of engines, transmission type, gross weight, creator, creation time, modification time, solution evaluation ID, indicator ID, model, unit ID, transmission system BOM, design requirements). Perform digital design of the design prototype, including unit type, and conduct multiple solution evaluation and optimization. The design prototype ID is the primary key, while the solution evaluation ID, indicator ID, model, and unit IDs are foreign keys.

[0048] Manufacturing prototypes (digital manufacturing ID, processing type, machine model, tool type, tool material, processing time, creator, modifier, creation time, model, and manufacturing requirements). Digital manufacturing performs manufacturing-related projects and includes content corresponding to physical manufacturing. The primary key is the digital manufacturing ID, and the foreign keys are the material ID and model ID.

[0049] Assembly prototype (assembly ID, assembly method, assembler, assembly part type, fit tolerance, assembly metamodel, creator, creation time, modification time, assembly requirements). The primary key is assembly ID.

[0050] Digital testing of test prototypes (test ID, creation time, modification time, creator, modifier, test, type, test duration, test model, test mathematical model, result metamodel, test items, test requirements) simulates physical testing, compares it with physical testing, and provides test strategy planning and test result optimization. The primary key is the test ID, and the foreign key is the test item.

[0051] Test entry (model ID, name, type, description, value, creation time, creator, modifier, modification time). The test entry describes the physical test that the digital test system can simulate. The primary key is the model ID.

[0052] Requirements / indicators (indicator id, name, indicator value, description, unit, parent indicator id). Indicators are self-referencing relationships. Through the indicator table, the helicopter transmission system indicator allocation tree (similar to the transmission system assembly structure tree) can be expressed.

[0053] Solution (basic parameters ID, tail rotor speed, transmission type, number of engines, rotor output speed, engine output speed, engine output power, engine output power distribution). "Solution ID" is the primary key.

[0054] Model metadata (metadata id, name, model, type, description, value, creator, creation time, modification time). "Metadata id" is the primary key, and the foreign key "model" represents a one-to-many relationship between "model metadata" and "model".

[0055] Test results (test result id, name, description, type, file, image, load, model, creator, test method, creation time, modification time, test settings). "test result id" is the primary key and "model" is the foreign key.

[0056] Result metadata (metadata id, name, type, description, value, creator, test result, creation time, modification time). "Metadata id" is the primary key, and "test result" is the foreign key.

[0057] Configuration scheme (configuration scheme ID, name, description, creator, creation time, basic parameters, transmission type, scheme document). "Scheme ID" is the primary key, and "basic parameters" and "transmission type" are foreign keys.

[0058] Model (model id, name, type, description, scheme, material, file, image, creation time, modification time, model type, file extension). "Model id" is the primary key, and "scheme" and "material" are foreign keys.

[0059] The comprehensive database is established in S6, specifically: For structured data, the relational database MySQL is used for storage; For semi-structured data, it is stored in the relational database MySQL in the form of file streams; For unstructured data, MinIO is used to manage large files, and the storage indexes in MinIO are stored in the relational database MySQL.

[0060] The integrated database for the entire transmission system lifecycle leverages a relational database and file system to manage common engineering design standards (AGMA / GB / GJB / HB) and requirements models (DOORS or SysML models). The database also provides a unified access and conversion interface, enabling access to and retrieval of requirements models across the design, manufacturing, assembly, and testing phases. Key data generated at each stage can be stored in the comprehensive database using data access interfaces or through model import, enabling unified data management, analysis, comparison, and traceability.

[0061] The helicopter development process generates a vast amount of design data, test data, manufacturing data, assembly data, production and maintenance data, and more. All of this data requires unified management through a comprehensive database. Given the numerous sources and diverse data formats, different storage solutions are required based on the data type to facilitate subsequent data management. Structured data is typically stored and managed using a relational database. The platform uses the relational database MySQL to store this data. Semi-structured data can be stored on a remote server as a file stream, with fixed upload and download paths to ensure file storage and access. Small, unstructured data, such as files, text documents, and images, is stored entirely on a remote server, with their storage locations recorded. Metadata is used to describe this unstructured data, with the metadata and file paths stored in a MySQL database for management. For larger, unstructured data, such as CAD / CAE models, MinIO can be used for large file management. MinIO is very suitable for storing large amounts of unstructured data. After large files and models are stored in MinIO, metadata is used to describe the large files and models. Then, the metadata and the storage index in MinIO are stored in the MySQL database. The platform data storage technology architecture solution is as follows: Figure 5 .

[0062] All data in the platform are stored in the MySQL database for unified management, which can eliminate data redundancy as much as possible, improve data quality, unify data sources, ensure that data flowing in the platform are interconnected, and break the "data island".

[0063] In S6, the models established in each stage are stored in a comprehensive database. Specifically, the demand model, functional model, logical model, physical model, design model, manufacturing model, assembly model and test model are saved in the comprehensive database through XML and JSON interfaces to achieve closed-loop iteration of requirements and indicators and full-process data monitoring.

[0064] Changes to requirements, design, manufacturing, and delivery data during the development of the helicopter transmission system digital prototype result in data version changes and data baseline changes. The data change control process isn't strictly enforced at the initial stage of system development, but rather should be implemented after the data baseline is established. ISO 29148 (Systems and software engineering—Life cycle processes—Requirements engineering, 2018) stipulates that data baselines should be maintained throughout the system lifecycle. A data baseline embodies the shared understanding of system functionality among all stakeholders. In practice, a data baseline is a collection of stakeholder data, system data, and design constraints, resulting from consensus, a solidified version, and authorized review. A data baseline is like a snapshot of a specific phase in the system lifecycle. This phase produces clear, stable outputs (such as data tables and SysML models), which have been reviewed and approved and serve as the foundation for further development. Once a data baseline is established, all data changes must strictly adhere to the data change control process and approval specifications. As data, system structure, or system processes change and iterate, the baseline is gradually transitioned to the next baseline.

[0065] As data changes and system iterations occur during the life cycle of a system, multiple versions of data will be generated. To address the issue of data iteration itself, version change control is used for management. The data management model will record the version of each data, record the new version when the data is updated, and save the old version; in addition, the data management model will associate the data version with the data baseline, and maintain a set of data baseline identifiers for each data. Therefore, each data can retrieve the data version information based on its unique identifier, and can also retrieve a series of data information based on the unique identifier of the data baseline, thereby tracing and changing the data iteration itself. If a data baseline and data version are Figure 6 shown.

[0066] Data structure iterative traceability refers to the tracing of the relationships between requirements, design, manufacturing, and delivery data throughout the entire process of helicopter transmission system digital prototype development. Data structure iterative traceability can be divided into downward data decomposition and upward data tracing.

[0067] (a) Data decomposition Data decomposition involves allocating and decomposing data along the "demand-design-manufacturing-delivery" path of the helicopter transmission system digital prototype development process. This creates a comprehensive evolutionary path from requirements to the helicopter transmission system digital prototype, enabling demand-driven forward design, manufacturing, and delivery. A breadth-first search algorithm based on the data management model is used to retrieve the data set along the decomposition direction. Source data is input, and all other data associated with it (data involved in the entire digital prototype design process) is traversed. Alternatively, source and target data are input, and a search algorithm based on the data management model is used to obtain a traceability path between the two data sets.

[0068] (b) Data tracing back to its source Data upstream tracing refers to tracing and verifying data from the delivery-manufacturing-design-requirements process, following the reverse direction of the helicopter transmission system digital prototype development process. This creates a full-process verification path from the helicopter transmission system digital prototype to the requirements, thereby determining whether the helicopter transmission system digital prototype meets the requirements. Because unidirectional data relationships may not exist between traceable data, the inverse adjacency matrix should be traversed when executing traversal or search algorithms. Furthermore, the verification, replication, and derivation relationships in the data management model can be converted into undirected edges before executing the tracing algorithm, resulting in a more complete traceability relationship.

[0069] Data traceability relies on data traversal and search algorithms. Through different forms of traceability and filtering conditions, a complete traceability path between data can be obtained, thereby realizing the traceability and verification of the helicopter transmission system digital prototype data in the entire process of "demand-design-manufacturing-delivery", and improving the efficiency of digital prototype research and development.

[0070] The reuse of helicopter transmission system digital prototype model includes three parts: model storage, model management and model reuse.

[0071] (a) Model storage The helicopter transmission system digital prototype involves model data for requirements, design, simulation, manufacturing, assembly, and testing. While the data formats and structures vary, the data carriers all use files. Therefore, the helicopter transmission system digital prototype model storage solution employs a "file storage + metadata description" approach to centrally store these models. The Java-based open-source library MinIO is used for distributed file storage and unified management. When uploading files, file sharding, shard upload, and resumable uploads are employed to achieve high-performance storage of large files (such as CAD and CAE files for the helicopter transmission system digital prototype). The open-source MySQL relational database is used to record model data descriptions. In addition to recording basic model information (such as the number of teeth, module, and stress and strain of each unit), the MinIO storage index of the model files is also recorded. This creates a helicopter transmission system digital prototype model library, enabling efficient storage of helicopter transmission system digital prototype models and laying the data foundation for model reuse.

[0072] (b) Model management Model management for helicopter transmission system digital prototypes includes model uploading, classification and filtering, and model display. During the helicopter transmission system digital prototype development process, designers create numerous models for different tasks. When designers upload models to the model library, they undergo multi-level review and approval, ensuring model quality through checks for correctness, completeness, and reusability. Model classification and filtering allows for the categorization and filtering of shared models stored in the model library. This supports classification and filtering by project, phase (e.g., design, simulation, manufacturing, assembly, and testing), model, unit (e.g., gears, shafts, bearings), and release date, enabling rapid location and search of shared models. Model display visualizes the models stored in the model library. Based on basic model information stored in MySQL and data extraction technology, model data is parsed and extracted, and the models are visualized using a visualization engine. Through model review and release, classification and filtering, and visualization, centralized management of helicopter transmission system digital prototype models is achieved.

[0073] (c) Model reuse Based on the storage and management of helicopter transmission system digital prototype models, helicopter transmission system digital prototype models can be reused. With the support of a model library, designers developing helicopter transmission system digital prototypes can use classification and filtering functions to retrieve shared models related to the current design task (such as requirements, design, simulation, manufacturing, assembly, and test models) from the model library. They can then select models for download and edit or reuse them in corresponding file editors (such as MDesign, DOORS, CATIA, and ANSYS) to complete their design tasks. Designers can also build models based on their own design experience and knowledge. Through operations such as model upload and multi-level review, they can store their own models in the model library, enabling the sharing of design experience and knowledge and model reuse. By collecting the design experience and common configurations of helicopter transmission systems, designers create a helicopter transmission system model library (including common transmission units such as gears, shafts, and bearings); other designers can quickly build the logical architecture of the helicopter transmission system based on the shared models in the model library, forming a helicopter transmission system configuration, reducing the designers' repeated design work and improving the efficiency of model development; on this basis, designers carry out detailed design of the helicopter transmission system (including the modification of gear tooth profile, the distribution of bearings, the assembly relationship and spatial position of gears and shafts, etc.), forming a physical model of the helicopter transmission system, such as Figure 7 .

[0074] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and it should be understood that the scope of protection of the present invention is not limited to such specific descriptions and embodiments. Those skilled in the art can make various other specific variations and combinations based on the technical teachings disclosed in the present invention without departing from the essence of the present invention, and such variations and combinations are still within the scope of protection of the invention.

Claims

1. A method for analyzing the overall technology of digital engineering of helicopter transmission system, characterized by: The following steps are involved: S1: Build a digital environment for the overall design of helicopter transmission systems; S2: Based on the established digital environment for helicopter transmission system overall design, requirements are captured for all stakeholders and scenarios. S3: Based on demand capture, obtain the preliminary design requirements, node parameters, interface requirements and overall requirements of the helicopter transmission system; S4: Based on preliminary design requirements, node parameters, interface requirements and overall requirements, conduct helicopter transmission system-component-parts requirements analysis and establish requirements model, functional model, logical model and physical model; S5: Establish design model, manufacturing model, assembly model and test model; S6: Establish a comprehensive database and store the models established in each stage in the comprehensive database to achieve numerical model reuse and complete the digital design closed loop.

2. The analysis method of the overall technology of digital engineering of helicopter transmission system according to claim 1 is characterized in that: The digital environment for the overall design of the helicopter transmission system in S1 includes a client, a functional layer, a core service layer, a data support layer, a database, and an application server; The client, database, and application server all include an integrated platform system typified by a model and data platform, as well as various tool software that support all technical and management activities throughout the entire life cycle, including simulation and analysis software, design and modeling software, data acquisition and analysis software, and engineering management software; The functional layer realizes end-to-end connection from demand to delivery and use in the time dimension, and realizes the connection between the physical and virtual worlds in the spatial dimension; The core service layer is oriented towards the entire life cycle of the helicopter transmission system, with digital clues based on models and data as the core, using the overall requirements of the helicopter transmission system digital engineering, including demand definition and modeling services, indicator system construction services, unification and coordination services, heterogeneous system association services and data visualization customization services; The data support layer includes a continuous and consistent model system and data, including: engineering standards, demand data, design data, simulation data, manufacturing data, assembly data and test data. The data model and business rules are sorted out in the data support layer, and logical associations and multi-view mapping rules between various types of data are established.

3. The analysis method of the overall technology of helicopter transmission system digital engineering according to claim 1 is characterized in that: In S2, requirements are captured from all stakeholders and in a scenario-oriented manner. The following steps are included: S21: Conduct context analysis on the helicopter transmission system to obtain the connection mode and material exchange form of each system with the helicopter transmission system. The systems connected with the helicopter transmission system include the fuselage system, power system, rotor system, avionics system, fuel supply system, control system and lubricating oil system. S22: Define the operational scenarios of the helicopter transmission system. Based on the overall helicopter design requirements, propose transmission system requirements for the operational scenarios for all stakeholders. Use DOORS or tools that support the SysML language to digitally capture, characterize, and define relationships for the helicopter transmission system requirements. S23: Establish initial requirements for the helicopter transmission system. The initial requirements are in the form of text documents or requirements managed in DOORS.

4. The analysis method of the overall technology of helicopter transmission system digital engineering according to claim 1 is characterized in that: The preliminary design requirements, node parameters, interface requirements and overall requirements of the helicopter transmission system in S3 include: Overall layout requirements: The overall layout requirements include weight, size, main reduction interface, tail reduction interface and skeleton model; Performance index requirements: The performance index requirements include power, transmission efficiency, weight, dry running, ballistic resistance, strength, compensation capability, vibration and noise; Functional requirements: These functional requirements include speed steering, power transmission, steering matching, lubrication and cooling, accessory transmission, and working mode switching; General quality characteristics and standardization requirements: The general quality characteristics and standardization requirements include reliability, maintainability, security, testability, safety and environmental adaptability.

5. The analysis method of the overall technology of digital engineering of helicopter transmission system according to claim 1 is characterized in that: The requirement model in S4 is represented by structured text using a modeling tool to sort out stakeholders and capture top-level task requirements. Model refinement is used to decompose top-level requirements into system requirements, system requirements into subsystem requirements, and subsystem requirements into component requirements. Realize demand traceability analysis and satisfaction verification; The functional model is structured using the SysML language to describe functional goals and conduct functional black box analysis based on use cases; it also describes interface relationships and establishes a traceable relationship between requirements and functions. The logical model adopts SysML language to form a logical model of the transmission system according to the assigned functions, which is used for logical structure representation, function allocation of each level of the system, parameter index allocation, interface design and parameter definition; The physical model is based on CATIA to complete the three-dimensional structure construction of the helicopter transmission system, carry out data transmission interface and analysis research between various models, and complete the digital description of each model data.

6. The method for analyzing the overall technology of digital engineering of a helicopter transmission system according to claim 1, characterized in that: The method for establishing the design model, manufacturing model, assembly model and test model in S5 is: Design model: It consists of requirements assigned to the design phase, design parameter text, and ANSYS and ABAQUS simulation tools for single-discipline performance and multi-discipline joint simulation of the transmission system; Manufacturing model: It is composed of the requirements assigned to the manufacturing stage, manufacturing process text data, manufacturing process inspection data, and manufacturing process simulation model; Assembly model: It consists of requirements assigned to the assembly stage, assembly process design, assembly process data analysis and collection, assembly process structure and process visualization model; Test model: It is composed of the requirements assigned to the test phase, test results, and measurement point information models.

7. The analysis method of the overall technology of helicopter transmission system digital engineering according to claim 1 is characterized in that: The comprehensive database is established in S6, specifically: For structured data, the relational database MySQL is used for storage; For semi-structured data, it is stored in the relational database MySQL in the form of file streams; For unstructured data, MinIO is used to manage large files, and the storage indexes in MinIO are stored in the relational database MySQL.

8. The method for analyzing the overall technology of digital engineering of a helicopter transmission system according to claim 1, characterized in that: In S6, the models established in each stage are stored in a comprehensive database. Specifically, the demand model, functional model, logical model, physical model, design model, manufacturing model, assembly model and test model are saved in the comprehensive database through XML and JSON interfaces to achieve closed-loop iteration of requirements and indicators and full-process data monitoring.

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