Maintenance reachability simulation optimization method and system oriented to multi-task scene

Abstract

The invention provides a multi-task scene-oriented maintenance reachability simulation optimization method and system, and relates to the technical field of spacecraft maintenance engineering, and the method comprises the steps: determining an index constraint condition; constructing a digital human body model library, and determining an operation constraint condition; building a three-dimensional digital prototype environment of operation, and executing process simulation and evaluation of a multi-element maintenance task scene according to index constraint conditions and operation constraint conditions by embedding a digital human body model; according to the simulation evaluation data, the maintenance difficulty is identified, risk quantitative evaluation is carried out, and a maintenance improvement scheme is generated; and an accessibility criterion is excavated, and maintenance operation guidance is carried out. The technical problem that in the prior art, due to the fact that maintainability analysis lags behind and the multi-task scene evaluation capability is insufficient, the maintenance reachability problem can only be passively found in the physical model machine stage, and then the maintenance effect is affected is solved, quantitative modeling and digital simulation are combined, the maintenance reachability of the rocket is evaluated, and the maintenance efficiency of the rocket is improved. And the maintenance effect is improved.

Description

Technical Field

[0001] This application relates to the field of spacecraft maintainability engineering technology, specifically to a simulation optimization method and system for maintenance accessibility in multi-mission scenarios. Background Technology

[0002] The economic viability of reusable rockets heavily relies on rapid turnaround capabilities, and maintenance accessibility is a key bottleneck restricting maintenance efficiency and impacting launch preparation cycles. In traditional rocket design, maintainability is often not a primary consideration, leading to time-consuming and laborious disassembly of other structures during maintenance of certain components, thus prolonging maintenance cycles. For reusable rockets, due to the need for frequent maintenance, poor accessibility will severely restrict launch preparation speed. Especially in multi-mission scenarios, different missions may involve different maintenance items and environmental conditions, making it difficult for traditional experience to assess accessibility in all situations in a timely manner. On the one hand, it heavily relies on field exercises during the physical prototype stage, resulting in delayed problem identification and high design change costs; on the other hand, although human factors engineering simulation tools exist, their application in rocket design is mostly fragmented and localized single-mission analysis, lacking a systematic approach oriented towards the entire system and spanning the entire design process. Furthermore, it struggles to address the complex multi-scenario evaluation needs under different mission profiles and combinations of maintenance items, preventing the pre-emptive elimination of maintenance bottlenecks during the design phase and consequently affecting maintenance effectiveness.

[0003] In summary, existing technologies suffer from technical problems where maintainability issues can only be passively discovered at the physical prototype stage due to the lag in maintainability analysis and insufficient multi-task scenario evaluation capabilities, which further affects the maintenance effectiveness. Summary of the Invention

[0004] The purpose of this application is to provide a simulation optimization method and system for maintenance accessibility in multi-task scenarios, in order to solve the technical problem in the prior art that maintenance accessibility problems can only be passively discovered at the physical prototype stage due to the lag in maintainability analysis and the insufficient evaluation capability of multi-task scenarios, which further affects the maintenance effect.

[0005] To achieve the above objectives, this application provides a simulation optimization method and system for maintenance accessibility in multi-task scenarios.

[0006] Firstly, this application provides a maintenance accessibility simulation optimization method for multi-task scenarios. This method is implemented through a maintenance accessibility simulation optimization system for multi-task scenarios. The method includes: determining top-level maintainability goals; quantifying and decomposing maintainability indicators as constraints; constructing a digital human body model library; determining operational constraints through multi-faceted maintenance posture simulation, where the operational constraints include the required spatial and passageway dimensions for maintenance operations; building a three-dimensional digital prototype environment for the operation; placing the digital human body model library into the system; and, based on the indicator and operational constraints, performing process simulation and evaluation of multi-faceted maintenance task scenarios to determine simulation evaluation data, where the simulation evaluation data includes at least component accessibility, task maintenance time, and operational interference; identifying maintenance difficulties and conducting risk quantification assessments based on the simulation evaluation data; and generating maintenance improvement plans based on the maintenance improvement plans. Finally, it identifies accessibility criteria to guide maintenance operations.

[0007] Optionally, an allocation model is established based on system complexity, layout structure, and historical maintenance data; according to the allocation model, the top-level maintainability target is mathematically decomposed and dynamically adjusted, and allocated as the average repair index of each subsystem as the index constraint condition, wherein the top-level maintainability target includes at least the top-level maintenance time target.

[0008] Optionally, the digital human body model library contains digital human body models at different human body size percentiles; the channel size requirements include a minimum channel size and a recommended channel size considering operational margins.

[0009] Optionally, a multi-functional maintenance task scenario is simulated, wherein the multi-functional maintenance task scenario includes at least engine inspection, component replacement and pipeline repair; simulation process data is recorded, wherein the simulation process data includes at least the movement path, operation posture and collision with surrounding structures; the standard time consumption of each maintenance step is measured on the simulation process data, the total task time is calculated cumulatively, and the compliance of the indicator constraints is judged.

[0010] Optionally, a risk assessment index is used to rate the maintenance difficulties and determine the rating data, wherein the rating includes a severity rating and an occurrence probability rating; based on the rating data, maintenance improvement needs are determined and the maintenance improvement plan is generated.

[0011] Optionally, the accessibility criteria include at least one of the following: layout criteria, interface criteria, spatial criteria, channel criteria, priority criteria, and security criteria.

[0012] Optionally, the layout criteria specify the layout requirements for high-failure-rate components; the interface criteria specify the arrangement requirements for inspection ports and quick-replacement interfaces; the space criteria specify the minimum clearance dimensions for the main work areas of personnel; the passage criteria specify the minimum diameter, maximum length, and minimum turning radius of maintenance passages; the priority criteria specify the priority of standardized and modular components and fasteners; and the safety criteria specify maintenance posture constraints.

[0013] Secondly, this application also provides a maintenance accessibility simulation optimization system for multi-task scenarios, used to execute a maintenance accessibility simulation optimization method for multi-task scenarios as described in the first aspect. The system includes: a quantification decomposition module for determining top-level maintainability goals and performing maintainability index quantification and decomposition as index constraints; a multi-dimensional maintenance posture simulation module for constructing a digital human body model library and determining operational constraints through multi-dimensional maintenance posture simulation, wherein the operational constraints include the required spatial and passageway dimensions for maintenance operations; a simulation evaluation module for building a three-dimensional digital prototype environment for operations, placing the digital human body model library, and performing process simulation and evaluation of multi-dimensional maintenance task scenarios based on the index constraints and operational constraints to determine simulation evaluation data, wherein the simulation evaluation data includes at least component accessibility, task maintenance time, and operational interference; a risk quantification evaluation module for identifying maintenance difficulties and performing risk quantification evaluation based on the simulation evaluation data, generating maintenance improvement plans; and an accessibility criterion mining module for mining accessibility criteria based on the maintenance improvement plans to guide maintenance operations.

[0014] One or more technical solutions provided in this application have at least the following technical effects or advantages: By defining top-level maintainability goals and quantifying and decomposing maintainability indicators as constraints, a digital human body model library is constructed. Through multi-faceted maintenance posture simulation, operational constraints are determined, including spatial and passageway size requirements for maintenance operations. A three-dimensional digital prototype environment for the operation is built. By incorporating the digital human body model library and based on the indicator and operational constraints, process simulation and evaluation of multiple maintenance task scenarios are performed to determine simulation evaluation data. This data includes at least component accessibility, task maintenance time, and operational interference. Based on the simulation evaluation data, maintenance difficulties are identified and risk quantification assessments are conducted, generating maintenance improvement plans. Based on these improvement plans, accessibility criteria are identified to guide maintenance operations. In other words, by defining indicator constraints and operational constraints, a digital human body model library is constructed, a three-dimensional digital prototype environment for operations is built, and various maintenance task scenarios are simulated based on maintainability indicator constraints and operational constraints. Based on simulation evaluation data, difficulties and challenges in the maintenance process are identified, and risk quantification assessment is conducted. Based on the identified maintenance difficulties and risk assessment results, targeted maintenance improvement plans are formulated to reduce potential risks in the maintenance process, improve maintenance effectiveness, and significantly improve the maintenance and support efficiency of reusable rockets.

[0015] The above description is merely an overview of the technical solution of this application. To better understand the technical means of this application and to facilitate its implementation according to the description, and to make the above and other objects, features, and advantages of this application more apparent, specific embodiments of this application are described below. It should be understood that the content described in this section is not intended to identify key or important features of the embodiments of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent through the following description. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating a maintenance accessibility simulation optimization method for multi-task scenarios proposed in this application.

[0018] Figure 2 This is a schematic diagram of the structure of a maintenance accessibility simulation optimization system for multi-task scenarios according to this application.

[0019] Figure labeling: Quantitative decomposition module 11, Multi-dimensional maintenance posture simulation module 12, Simulation evaluation module 13, Risk quantification evaluation module 14, Accessibility criterion mining module 15. Detailed Implementation

[0020] This application provides a simulation optimization method and system for maintenance accessibility in multi-mission scenarios. It addresses the technical problem in existing technologies where maintenance accessibility issues are only passively discovered at the physical prototype stage due to lagging maintainability analysis and insufficient multi-mission scenario evaluation capabilities, further impacting maintenance effectiveness. By defining indicator constraints and operational constraints, a digital human model library is constructed, and a three-dimensional digital prototype environment for operations is built. Based on the maintainability indicator constraints and operational constraints, diverse maintenance task scenarios are simulated. Based on the simulation evaluation data, difficulties and challenges in the maintenance process are identified, and risk quantification assessments are performed. Based on the identified maintenance difficulties and risk assessment results, targeted maintenance improvement plans are formulated to reduce potential risks in the maintenance process, improve maintenance effectiveness, and significantly enhance the maintenance and support efficiency of reusable rockets.

[0021] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. It should be understood that this application is not limited to the exemplary embodiments described herein. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. It should also be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, not all of them.

[0022] Example 1, please refer to the appendix. Figure 1 This application provides a maintenance accessibility simulation optimization method for multi-task scenarios. The method is applied to a maintenance accessibility simulation optimization system for multi-task scenarios, and specifically includes the following steps: S100: Determine the top-level maintainability objectives, quantify and decompose maintainability indicators, and use them as indicator constraints.

[0023] Furthermore, S100 of this application includes: establishing an allocation model based on system complexity, layout structure and historical maintenance data; and mathematically decomposing and dynamically adjusting the top-level maintainability target according to the allocation model, allocating it as the average repair index of each subsystem as the index constraint condition, wherein the top-level maintainability target includes at least a top-level maintenance time target.

[0024] Specifically, based on the reusable operation and maintenance requirements of the rocket, overall maintainability targets are set, such as requiring the rocket's Mean Time To Repair (MTTR) to not exceed a certain threshold. Benchmarking against preset standards and experience with similar products, the allocation strategy for these indicators across the rocket's various systems is clarified. A mathematical model is established to decompose and allocate the rocket's top-level MTTR target to each major system and subsystem, considering the complexity, hierarchical structure, and historical data of different systems to calculate the initial maintainable time index for each system. Then, considering the rocket's unique layout and modularity, the initial values ​​are adjusted and optimized to finally determine the MTTR design index for each subsystem / equipment level. This will constrain the design of each device, such as the number of interfaces and installation location, ensuring that it can be disassembled and repaired within the specified time. In other words, using the rocket's top-level MTTR target as input, the complexity factor and layout accessibility factor of each subsystem are systematically quantitatively evaluated, and a weighted calculation is performed with reference to the baseline time in historical maintenance data to initially derive the MTTR allocation value for each subsystem.

[0025] Top-level maintainability objectives are the highest-level performance indicators for maintainability set for the entire reusable rocket, typically quantified by the top-level maintenance time target (MTTR). The constraint on this indicator is the average repair time target for each subsystem, a mandatory requirement that directly impacts the selection of subsystem design options. By clearly defining the subsystem maintenance time target, it ensures that each subsystem meets the overall rapid maintenance requirements from a design perspective, avoiding the problem of certain subsystems dragging down overall maintenance efficiency in traditional designs.

[0026] S200: Construct a digital human body model library, and determine the operation constraints by performing multi-dimensional maintenance posture simulations. The operation constraints include the space dimensions and passage size requirements required for maintenance operations.

[0027] Furthermore, S200 of this application includes: the digital human body model library contains digital human body models at different human body size percentiles; the channel size requirements include a minimum channel size and a recommended channel size considering operational margin.

[0028] Specifically, to address the operational space and access requirements for maintenance personnel, a digital human body model and a digital human body model library are established, considering various postures (standing, kneeling, lying, squatting, and hand extension) and different body types (percentile of body size) for common reusable rocket maintenance operations. The digital human body model library is used to simulate the postures and range of motion of personnel performing maintenance inside / around the rocket in a 3D digital environment. This determines the workspace requirements for each typical maintenance task and extracts design guidelines for personnel-accessible areas. For example, it requires that space be provided around a certain piece of equipment that allows simultaneous access for a person's head and hands, with dimensions meeting the standing operation requirements of the 95th percentile of personnel. Simultaneously, dimensional models of common maintenance access routes such as inspection ports, cover openings, and equipment gaps are established to determine the minimum access dimensions for arms and tools, as well as recommended dimensions with certain margins. These data serve as a qualitative design basis, guiding the rocket's structural layout and ensuring unobstructed maintenance paths.

[0029] This paper presents a design methodology for simulating multi-posture maintenance operations using digital human body models (DHMs). The DHM comprises human-machine models built according to different personnel body types, determining the dimensional requirements of maintenance workspaces and access routes, and embedding these into the rocket design process to constrain the layout. Specifically, it involves collecting anthropometric data and workspace standards for astronauts and ground maintenance personnel, such as referencing GJB standards. For typical rocket maintenance activities, multiple personnel postures of DHM models are constructed; for example, simulating a maintenance worker at the 95th percentile crouching inside the engine compartment operating valves. Simultaneously, a maintenance access route model library is established for the rocket structure, including the cross-sectional dimensions of typical hatches and pipe gaps. Using specialized simulation tools, the DHM models are combined with the rocket CAD model to annotate the required free space range for personnel in different postures, as well as the required diameter / width of access routes for arms and tools. The paper records whether the current design meets these requirements as preparation for subsequent simulation verification.

[0030] The minimum passage size is the theoretical limit for a body part or tool to barely pass through, without considering operational comfort or efficiency, only ensuring accessibility. The recommended passage size is the minimum size with an added operational margin. This step ensures that the design provides sufficient human-machine space, eliminating the potential for personnel to be unable to enter or have their operations restricted.

[0031] S300: Build a three-dimensional digital prototype environment for the operation. By placing the digital human body model library, and based on the index constraints and operation constraints, perform process simulation and evaluation of multiple maintenance task scenarios to determine the simulation evaluation data. The simulation evaluation data includes at least component accessibility, task maintenance time, and operation interference.

[0032] Furthermore, S300 of this application includes: simulating a multi-functional maintenance task scenario, wherein the multi-functional maintenance task scenario includes at least engine inspection, component replacement and pipeline repair; recording simulation process data, wherein the simulation process data includes at least movement path, operating posture and collision with surrounding structures; measuring the standard time consumption of each maintenance step on the simulation process data, calculating the total task time, and making a compliance judgment on the indicator constraints.

[0033] Specifically, a 3D digital prototype environment for the operation is built, and a digital human body model library is placed within this environment to simulate the actions of maintenance personnel in different task scenarios. Multiple maintenance task scenarios are selected, such as rapid engine replacement, electronic equipment inspection, and propellant pipeline leak repair, and these are simulated in a virtual environment following real-world steps. The simulation observes whether maintenance personnel can smoothly approach the target components, whether their body parts collide with surrounding structures, and whether their line of sight is obstructed. Difficulties encountered during the simulation are recorded, such as insufficient operating space requiring special tools, and inconvenience in retrieving and placing parts. In other words, several typical maintenance task scenarios are selected, and the maintenance process for each scenario is simulated using digital simulation software. For example, routine engine inspections are simulated by having personnel enter the engine compartment to inspect the wear and tear of key sensors and components; booster separation mechanism failure replacements are simulated by quickly replacing failed separation bolts or latches at the launch site; electronic equipment board replacements are simulated by opening the avionics equipment compartment and replacing damaged circuit boards; and propellant pipeline leak repairs are simulated by detecting and replacing leaking hydrogen pipeline joints.

[0034] In each simulation, the maintenance personnel's movement path, operating posture, required space, and time are recorded. Collision detection is used to determine if any components obstruct the operation, and the total task time is calculated by accumulating the time to assess whether it exceeds the limit. Difficulties encountered in the simulation (such as insufficient space or inability to reach bolts) are recorded in detail.

[0035] The diverse maintenance task scenarios are a series of representative virtual maintenance tasks designed to comprehensively verify maintainability. They cover maintenance work types with different frequencies, complexities, and urgency levels, including engine inspection, component replacement, and pipeline repair. The simulation process data is quantitative and geometric information reflecting the details of the maintenance process, automatically recorded by the software during the digital simulation execution, including movement paths, operating postures, and collision scenarios.

[0036] In the simulation, set the expected time for each maintenance step, assigning values ​​based on standard manuals or past experience, such as the time X seconds for tightening a bolt. Measure the standard time for each maintenance step in the simulation process data, and calculate the total task time, i.e., the total time for the entire task flow, to obtain the simulated maintenance time for the task. Compare the simulated maintenance time with the design target to evaluate whether it meets the requirements. For those exceeding the target, record the specific bottleneck steps. Observe through simulation to verify whether each component to be maintained can be effectively reached by personnel or tools. If a part is unreachable or not visible in the simulation, it is determined that there is an accessibility problem in the design and improvement is needed. For example, if the inspection port of a valve is blocked by a nearby structure, and the simulation shows that tools cannot be inserted, it is considered inaccessible. For example, if the standard time for each maintenance step is 163 seconds, approximately 2.7 minutes, and the preset standard time is: reaching for a wrench 0.9s, walking to the installation point 1.08s, aligning and connecting / disconnecting electrical connectors 1.44s, aligning and loosening / tightening a bolt, assuming there are 2 electrical connectors and 4 fixing bolts, then the average repair time (MTTR) is set to less than 5 minutes. The simulation result of 2.7 minutes is less than 5 minutes, therefore the maintainability design of this component meets the performance constraints. This step can verify accessibility and quantify maintenance time during the design phase, identifying structural bottlenecks that need improvement early on.

[0037] S400: Based on the simulation evaluation data, identify maintenance difficulties and conduct risk quantification assessment to generate maintenance improvement plans.

[0038] Furthermore, S400 of this application includes: using a risk assessment index to rate the maintenance difficulties and determine the rating data, wherein the rating includes a severity rating and an occurrence probability rating; and based on the rating data, determining the maintenance improvement needs and generating the maintenance improvement plan.

[0039] Specifically, for challenges identified in simulations, a risk assessment index method is applied to quantitatively evaluate their impact. Each potential problem is rated according to its severity (impact on maintenance time and safety) and probability of occurrence, generating a risk matrix. If the risk index is too high, mandatory design modifications are required; if the risk is acceptable, usage precautions are provided. Risk acceptance criteria are established to ensure that remaining problems do not have unacceptable impacts on the task. Through digital simulation analysis, maintenance obstacles in the design can be identified early and their impact quantified, allowing for timely adjustments before design finalization.

[0040] In other words, based on the simulation results, the accessibility of each scenario is evaluated. All maintenance operation points deemed inaccessible or difficult in the simulation are listed, and the reasons are analyzed, such as insufficient space or limited angles. The total maintenance time for each scenario is compared with the performance requirements to identify tasks that exceed the time limit and the most time-consuming steps. Using a digital human body model, it is verified whether the design meets the workspace and access dimensions required for the corresponding postures, and specific areas that do not meet the requirements are identified. To address these issues, design modification schemes are proposed, such as increasing the diameter of a certain access port, moving a sensor to make it more accessible, or changing the fastening method to reduce disassembly steps.

[0041] In summary, this mechanism, which uses a risk index method to assess the severity and probability of maintainability issues discovered in simulations to determine whether design optimization is necessary, ensures that design modifications are based on sound reasoning and balances maintainability and cost-effectiveness. This step enables timely identification of maintainability challenges and allows for targeted improvements, facilitating adjustments before design finalization.

[0042] S500: Based on the aforementioned maintenance improvement plan, explore accessibility criteria and provide maintenance operation guidance.

[0043] Furthermore, S500 of this application includes: the reachability criteria include at least one of the following: layout criteria, interface criteria, spatial criteria, channel criteria, priority criteria, and security criteria.

[0044] Furthermore, this application also includes the following steps: the layout criteria specify the layout location requirements for high failure rate components; the interface criteria specify the arrangement requirements for inspection ports and quick replacement interfaces; the space criteria specify the minimum clearance dimensions of the main work area for personnel; the passage criteria specify the minimum diameter, maximum length, and minimum turning radius of maintenance passages; the priority criteria specify the priority of standardized and modular components and fasteners; and the safety criteria specify maintenance posture constraints.

[0045] Specifically, based on the achievement of quantitative indicators, human factors simulation results, and risk assessment, a maintenance accessibility design improvement plan will be developed. This includes adjusting the equipment layout to bring frequently inspected components closer to maintenance ports or easily accessible external locations; adding inspection holes or larger hatches to meet personnel access and observation needs; modifying the type or number of fasteners to reduce disassembly steps and achieve rapid release; providing specialized tooling or guiding devices to assist in disassembly and assembly operations in confined spaces; and transferring certain complex maintenance tasks from the aircraft level to a higher maintenance level, replacing them on-site and overhauling them at a rear base.

[0046] Accessibility criteria are a systematic and rule-based set of design rules designed to guide rocket design from the outset, ensuring excellent maintainability. Accessibility criteria cover layout, interfaces, space, access, and safety, directly guiding subsequent design and possessing repeatability. They include at least one of the following: layout criteria, interface criteria, space criteria, access criteria, priority criteria, and safety criteria. Layout criteria specifically address the rules for arranging components within the rocket cabin space. Its core idea is to drive layout decisions based on failure rates. Interface criteria address the design rules for the interaction between components and maintenance personnel, primarily covering physical interfaces used for inspection, testing, and quick replacement. Space criteria set minimum three-dimensional space requirements to ensure maintenance personnel or parts of their bodies can enter and perform operations. Access criteria set path geometry requirements to ensure tools, spare parts, or personnel limbs can easily reach maintenance areas. Priority criteria provide guidance for component and fastener selection, emphasizing standardization and modularization to simplify maintenance processes and reduce tool types and operational steps. Safety criteria, from the perspective of protecting the safety and health of maintenance personnel, impose restrictive requirements on maintenance posture and operating environment, directly reflecting ergonomics. For example, layout guidelines stipulate that frequently maintained / vulnerable parts should be placed in easily accessible locations, avoiding placement in confined or narrow spaces; interface guidelines require that commonly used inspection ports and quick-replacement ports be placed in easily accessible and visible locations, with extensions to the outside if necessary; space guidelines ensure sufficient clearance in main work areas, such as an area with a diameter ≥ 500mm to accommodate the upper body; passageway guidelines require maintenance passageways connecting multiple sections to have a diameter ≥ Xmm, straight section length ≤ Ymm, and turning radius ≥ Zmm to ensure smooth passage of tools and spare parts; standard parts should prioritize the use of standardized and modular components and fasteners to reduce the use of specialized tools and improve replacement efficiency; safety guidelines avoid prolonged periods of holding the device high or twisting it during maintenance, and tooling supports should be designed where necessary to ensure personnel safety and comfort. Accessibility guidelines will be clearly defined in subsequent rocket detailed design specifications, requiring designers of all subsystems to follow them, thus ensuring that accessibility requirements are implemented systematically.

[0047] The modified design was simulated again to verify that all critical maintenance tasks were achievable and met the time requirements. If shortcomings remained, iterative adjustments were continued until the requirements were met. Finally, the effectiveness of the accessibility design was verified through actual maintenance drills during the engineering prototype phase. If any discrepancies were found with simulation expectations, the simulation model and accessibility criteria were revised promptly to make the methodology more comprehensive and conservative. For solutions to specific problems, improved maintenance accessibility design plans were developed, and maintenance accessibility design criteria were refined to guide rocket design optimization. These criteria were also specified to be incorporated into design specifications to guide engineers in improving the design.

[0048] For example, based on mission requirements, the overall average repair time target for the rocket is set to ≤120 minutes. A weighted allocation model is established based on system complexity, layout structure coefficients, and historical maintenance data. The complexity weight of the liquid oxygen delivery subsystem is C=0.4, and the layout coefficient is L=1.3. The initial calculation yields an average repair time allocation of 65 minutes for the liquid oxygen delivery subsystem. After design review and consideration of engineering realities, the final constraint for this subsystem is determined to be an average repair time target of ≤70 minutes. A digital human body model library is constructed for the liquid oxygen pump replacement task. Attitude simulation determines the minimum required working space to be 800mm×600mm×1200mm. The minimum channel diameter required for tool insertion is determined to be 150mm, with a recommended channel diameter of 220mm, including operational margin. The liquid oxygen pump unit replacement task is simulated, including steps such as disconnecting cables, removing fixing bolts, removing the old pump, and installing the new pump. The maintenance worker's movement trajectory from the hatch to the pump body was recorded, with a path length of 3.5 meters. When disassembling the bottom bolts, the worker adopted a bent-over, crouched posture, resulting in a RULA score of 7, indicating high risk. Simulation revealed a 25mm geometric interference between the disassembly tool and the adjacent support. The standard time for each step was calculated using the MODAPTS method, with a total task time of 95 minutes. The result indicates that 95 minutes > 70 minutes, failing to meet the performance constraints. The maintenance difficulty lies in the interference between the tool and the support. This difficulty, discovered in the simulation, prevents task completion, severely impacting maintenance safety and time, resulting in a severity rating of 9. This error is inevitable with every task execution, hence the probability rating is 10. The risk assessment index is calculated to be 0.9, indicating high risk, necessitating design modifications. The proposed solution involves shifting the support position 40mm towards the bulkhead and optimizing the tool's motion envelope. Based on the aforementioned analysis, the accessibility criteria include: layout criteria—high-frequency replacement components such as liquid oxygen pumps should be located within ≤800mm of the inspection port; access criteria—the diameter of the main maintenance access channel should be ≥220mm; and safety criteria—the maintenance attitude RULA score should be ≤5, otherwise additional support fixtures or layout modifications are required. During the rocket engineering prototype stage, a physical maintenance exercise was conducted on the optimized liquid oxygen delivery subsystem. Before the improvement, maintenance personnel could not disassemble the pump body using standard tools, requiring special fixtures, and the measured maintenance time was approximately 115 minutes. After the improvement, the maintenance process was smooth, with no interference, and the measured maintenance time was reduced to 68 minutes. The simulation-estimated time highly matched the measured value, with an error within an acceptable range (less than 5%), proving the high accuracy and engineering applicability of this method. The improved design meets the requirement of an average repair time ≤70 minutes, improving maintenance efficiency by approximately 40%.

[0049] Traditional single-task optimization methods are prone to falling into the trap of prioritizing one task at the expense of another, meaning that optimizing the accessibility of one task may inadvertently worsen the maintenance conditions of other tasks. Compared to traditional methods that only optimize for a single task, this application selects simulations of multiple typical tasks (inspection, maintenance, repair, etc.) to ensure that the design meets maintenance accessibility requirements under various task conditions. This ensures that the rocket's maintainability design is not only optimized for a single task, but also maintains good accessibility and maintenance efficiency under various possible real-world operating conditions.

[0050] In summary, the maintenance accessibility simulation optimization method for multi-task scenarios provided in this application has the following technical effects: By defining top-level maintainability goals and quantifying and decomposing maintainability indicators as constraints, a digital human body model library is constructed. Through multi-faceted maintenance posture simulation, operational constraints are determined, including spatial and passageway size requirements for maintenance operations. A three-dimensional digital prototype environment for the operation is built. By incorporating the digital human body model library and based on the indicator and operational constraints, process simulation and evaluation of multiple maintenance task scenarios are performed to determine simulation evaluation data. This data includes at least component accessibility, task maintenance time, and operational interference. Based on the simulation evaluation data, maintenance difficulties are identified and risk quantification assessments are conducted, generating maintenance improvement plans. Based on these improvement plans, accessibility criteria are identified to guide maintenance operations. In other words, by defining indicator constraints and operational constraints, a digital human body model library is constructed, a three-dimensional digital prototype environment for operations is built, and various maintenance task scenarios are simulated based on maintainability indicator constraints and operational constraints. Based on simulation evaluation data, difficulties and challenges in the maintenance process are identified, and risk quantification assessment is conducted. Based on the identified maintenance difficulties and risk assessment results, targeted maintenance improvement plans are formulated to reduce potential risks in the maintenance process, improve maintenance effectiveness, and significantly improve the maintenance and support efficiency of reusable rockets.

[0051] Example 2: Based on the same inventive concept as the maintenance accessibility simulation optimization method for multi-task scenarios in Example 1, this application also provides a maintenance accessibility simulation optimization system for multi-task scenarios. Please refer to the appendix. Figure 2 The aforementioned maintenance accessibility simulation optimization system for multi-task scenarios includes: The quantification and decomposition module 11 is used to determine the top-level maintainability goals and perform maintainability index quantification and decomposition as index constraints. The multi-dimensional maintenance posture simulation module 12 is used to construct a digital human body model library and determine the operation constraints by performing multi-dimensional maintenance posture simulations. The operation constraints include the space size and passage size requirements required for maintenance operations. The simulation evaluation module 13 is used to build a three-dimensional digital prototype environment for the operation. By placing the digital human body model library, it performs process simulation and evaluation of multi-dimensional maintenance task scenarios based on the index constraints and operation constraints to determine simulation evaluation data. The simulation evaluation data includes at least component accessibility, task maintenance time, and operational interference. The risk quantification and evaluation module 14 is used to identify maintenance difficulties and perform risk quantification and evaluation based on the simulation evaluation data to generate maintenance improvement plans. The accessibility criterion mining module 15 is used to mine accessibility criteria based on the maintenance improvement plans to provide maintenance operation guidance.

[0052] Furthermore, the quantization decomposition module 11 in the maintenance accessibility simulation optimization system for multi-task scenarios is also used to: establish an allocation model based on system complexity, layout structure and historical maintenance data; and perform mathematical decomposition and dynamic adjustment on the top-level maintainability target according to the allocation model, allocating it as the average repair index of each subsystem as the index constraint condition, wherein the top-level maintainability target includes at least the top-level maintenance time target.

[0053] Furthermore, the multi-dimensional maintenance posture simulation module 12 in the maintenance accessibility simulation optimization system for multi-task scenarios is also used for: the digital human body model library containing digital human body models of different human body size percentiles; the channel size requirements including minimum channel size and recommended channel size considering operational margin.

[0054] Furthermore, the simulation evaluation module 13 in the maintenance accessibility simulation optimization system for multi-task scenarios is also used to: simulate multi-task maintenance scenarios, wherein the multi-task maintenance scenarios include at least engine inspection, component replacement and pipeline repair; record simulation process data, wherein the simulation process data includes at least movement path, operation posture and collision with surrounding structures; measure the standard time consumption of each maintenance step on the simulation process data, calculate the total task time, and make a compliance judgment on the index constraints.

[0055] Furthermore, the risk quantification assessment module 14 in the maintenance accessibility simulation optimization system for multi-task scenarios is also used to: use a risk assessment index to rate maintenance difficulties and determine rating data, wherein the rating includes severity rating and probability of occurrence rating; and determine maintenance improvement needs based on the rating data to generate the maintenance improvement plan.

[0056] Furthermore, the accessibility criterion mining module 15 in the maintenance accessibility simulation optimization system for multi-task scenarios is also used to: the accessibility criteria include at least one of the following: layout criteria, interface criteria, spatial criteria, channel criteria, priority criteria, and safety criteria.

[0057] Furthermore, the accessibility criterion mining module 15 in the maintenance accessibility simulation optimization system for multi-task scenarios is also used for: the layout criteria specifying the layout location requirements of high failure rate components; the interface criteria specifying the arrangement requirements of inspection ports and quick replacement interfaces; the space criteria specifying the minimum clearance size of the main work area for personnel; the passage criteria specifying the minimum diameter, maximum length, and minimum turning radius of maintenance passages; the priority criteria specifying the priority of standardized and modular components and fasteners; and the safety criteria specifying maintenance posture constraints.

[0058] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The maintenance accessibility simulation optimization method and specific examples for multi-task scenarios in the foregoing embodiment one are also applicable to the maintenance accessibility simulation optimization system for multi-task scenarios in this embodiment. Through the foregoing detailed description of the maintenance accessibility simulation optimization method for multi-task scenarios, those skilled in the art can clearly understand the maintenance accessibility simulation optimization system for multi-task scenarios in this embodiment. Therefore, for the sake of brevity, it will not be described in detail here.

[0059] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0060] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of this application and its equivalents, this application also intends to include such modifications and variations.

Claims

1. A simulation optimization method for maintenance accessibility in multi-task scenarios, characterized in that, include: Determine top-level maintainability goals, and quantify and decompose maintainability indicators as indicator constraints; A digital human body model library is constructed, and operational constraints are determined by simulating various maintenance postures. The operational constraints include the space and passage size requirements for maintenance operations. A three-dimensional digital prototype environment for the operation is built. By placing the digital human body model library into it, and based on the index constraints and operation constraints, the process simulation and evaluation of multiple maintenance task scenarios are performed to determine the simulation evaluation data. The simulation evaluation data includes at least component accessibility, task maintenance time and operation interference. Based on the simulated evaluation data, maintenance difficulties are identified and risk quantification assessments are conducted to generate maintenance improvement plans. Based on the aforementioned maintenance improvement plan, accessibility criteria are identified to guide maintenance operations.

2. The maintenance accessibility simulation optimization method for multi-task scenarios as described in claim 1, characterized in that, Implement the quantification and decomposition of maintainability indicators, including: An allocation model is established based on system complexity, layout structure, and historical maintenance data; According to the allocation model, the top-level maintainability target is mathematically decomposed and dynamically adjusted, and allocated as the average repair index of each subsystem as the index constraint condition. The top-level maintainability target includes at least the top-level maintenance time target.

3. The maintenance accessibility simulation optimization method for multi-task scenarios as described in claim 1, characterized in that, The digital human body model library contains digital human body models at different human body size percentiles; The channel size requirements include a minimum channel size and a recommended channel size that takes into account operational margins.

4. The maintenance accessibility simulation optimization method for multi-task scenarios as described in claim 1, characterized in that, Simulation and evaluation of the process of performing diverse maintenance tasks, including: Simulate diverse maintenance task scenarios, wherein the diverse maintenance task scenarios include at least engine inspection, component replacement, and pipeline repair; Record simulation process data, wherein the simulation process data includes at least the movement path, operation posture, and collision with surrounding structures; The simulation process data is used to measure the standard time consumption of each maintenance step, the total task time is calculated cumulatively, and the compliance of the indicator constraints is judged.

5. The maintenance accessibility simulation optimization method for multi-task scenarios according to claim 1, characterized in that, Identify maintenance challenges and conduct quantified risk assessments to generate maintenance improvement plans, including: A risk assessment index is used to rate the maintenance difficulties and determine the rating data. The rating includes a severity rating and an occurrence probability rating. Based on the rating data, the maintenance and improvement needs are determined, and the maintenance and improvement plan is generated.

6. The maintenance accessibility simulation optimization method for multi-task scenarios as described in claim 1, characterized in that, The reachability criteria include at least one of the following: layout criteria, interface criteria, spatial criteria, channel criteria, priority criteria, and security criteria.

7. The maintenance accessibility simulation optimization method for multi-task scenarios as described in claim 6, characterized in that, The layout guidelines specify the required placement of high-failure-rate components; The interface guidelines specify the layout requirements for inspection ports and quick-replacement interfaces; The space guidelines specify the minimum clearance dimensions for the main work areas of personnel; The passage guidelines specify the minimum diameter, maximum length, and minimum turning radius of the maintenance passageway; The priority criteria specify the priority of standardized, modular components and fasteners; The safety guidelines specify maintenance posture constraints.

8. A maintenance accessibility simulation optimization system for multi-task scenarios, characterized in that, The steps for implementing the maintenance accessibility simulation optimization method for multi-task scenarios according to any one of claims 1 to 7, wherein the maintenance accessibility simulation optimization system for multi-task scenarios comprises: The quantification and decomposition module is used to determine the top-level maintainability goals, perform maintainability indicator quantification and decomposition, and serve as indicator constraints. The multi-dimensional maintenance posture simulation module is used to build a digital human body model library. By performing multi-dimensional maintenance posture simulation, the operation constraints are determined, including the space size and passage size requirements required for maintenance operations. The simulation evaluation module is used to build a three-dimensional digital prototype environment for the operation. By placing the digital human body model library, and based on the index constraints and operation constraints, it performs process simulation and evaluation of multiple maintenance task scenarios to determine the simulation evaluation data. The simulation evaluation data includes at least component accessibility, task maintenance time, and operation interference. The risk quantification assessment module is used to identify maintenance difficulties and conduct risk quantification assessment based on the simulated assessment data, and generate maintenance improvement plans. The accessibility criterion mining module is used to mine accessibility criteria based on the maintenance improvement plan and to provide maintenance operation guidance.

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