Mechanical Dispatch Reliability Prediction for Civil Aircraft Considering Operational Parameters

To effectively predict the mechanical dispatch reliability(MDR),the artificial neural networks method combined with aircraft operation health status parameters is proposed,which introduces the real civil aircraft operation data for verification,to improve the modeling precision and computing efficiency.Grey relational analysis can identify the degree of correlation between aircraft system health status(such as the unscheduled maintenance event,unit report event,and services number)and dispatch release and screen out themost closely related systems to determine the set of input parameters required for the prediction model.The artificial neural network using radial basis function(RBF)as a kernel function,has the best applicability in the prediction of multidimensional,small sample problems.Health status parameters of related systems are used as the input to predict the changing trend ofMDR,under the artificial neural network modeling framework.The case study collects real operation data for a certain civil aircraft over the past five years to validate the performance of the model which meets the requirements of the application.The results show that the prediction quadratic error Ep of the model reaches 6.9×10−8.That is to say,in the existing operating environment,the prediction of the number of delay&cancel events per month can be less than once.The accuracy of RBF ANN,BP ANN and GA-BP ANN are compared further,and the results show that RBF ANN has better adaptability to such multidimensional small sample problems.The efforts of this paper provide a highly efficientmethod for theMDR prediction through aircraft system health state parameters,which is a promising model to enhance the prediction and controllability of the dispatch release,providing support for the construction of the civil aircraft operation system.

Research on MBSE Application for Radio Navigation System

The rapid development of concepts and technologies for civil aircraft navigation systems has put forward higher requirements for agile iteration and integrated design verification in the research and development(R&D)process.Traditional document based system engineering(DBSE)methods have gradually become inadequate.Model based system engineering(MBSE)is fully based on user′s needs and is carried out from top to bottom,in line with the concept of forward design.It is gradually being applied in the development of civil aircraft systems.This article focuses on the civil aircraft radio navigation system and proposes a complete system engineering solution based on models,from system design and development to validation.Guided by the Arcadia methodology,with Capella modeling tool,Simulink simulation tool,and system validation tool,the complete R&D process from design and development to testing and validation was achieved through model construction,code generation,and testing validation.A radio navigation station selection optimization method based on machine learning was proposed,and results had good signal quality and persistence.The verification result of Beijing⁃Shanghai flight route shows MBSE method practiced in this article can ensure the feasibility of the entire process of radio navigation system development,as well as the rationality of tuning and positioning result.By automatically generating code to form a universal functional module,an optimization method that integrates different radio navigation station selection strategies is achieved,providing new ideas for the development and design of radio navigation systems.

Civil Aircraft Assisted Space-Air-Ground Integrated Networks: Architecture Design and Coverage Analysis

In this paper, we propose a novel AIenabled space-air-ground integrated networks(SAGIN). This new integrated networks architecture consists of LEO satellites and civil aircrafts carrying aerial base stations, called "civil aircraft assisted SAGIN(CAA-SAGIN)". The assistance of civil aircrafts can reduce the stress of satellite networks, improve the performance of SAGIN, decrease the construction cost and save space resources. Taking the Chinese mainland as an example, this paper has analyzed the distribution of civil aircrafts, and obtained the coverage characteristics of civil aircraft assisted networks(CAAN). Taking Starlink as the benchmark, this paper has calculated the service gap of CAAN, and designed the joint coverage constellation. The simulation results prove that the number of satellites in CAASAGIN can be greatly reduced with the assistance of civil aircrafts at the same data rate.

Hierarchical Colored Timed Petri Nets for Maintenance Process Modeling of Civil Aircraft

Civil aircraft maintenance process simulation model is an effective method for analyzing the maintainability of a civil aircraft. First, we present the Hierarchical Colored Timed Petri Nets for maintenance process modeling of civil aircraft. Then, we expound a general method of civil aircraft maintenance activities, determine the maintenance level for decomposition, and propose the methods of describing logic of relations between the maintenance activities based on Petri Net. Finally, a time Colored Petri multi-level network modeling and simulation procedures and steps are given with the maintenance example of the landing gear burst tire of a certain type of aircraft. The feasibility of the method is proved by the example.

Optimization of Maintenance in Civil Aviation Aircraft Equipments

As the economic level rising,the function and stability of civil aircraft have been greatly improved.However,with the development of science and technology in modern civil aviation transportation,the frequent occurrence of flight accidents has threatened people’s safety.The main reason is the internal failure of the engine body or the daily maintenance management is incomplete.Therefore,the relevant maintenance management departments should attach great importance to the first core research and management of civil aircraft stability and safety.In view of various equipment problems existing in the operation of civil aircraft,the practical application of data collection mode and maintenance information disclosure mode of modern aircraft maintenance equipment is analyzed.This paper describes some characteristics of aircraft maintenance work,and combined with the main factors affecting the risk of civil aircraft maintenance,giving countermeasures and suggestions to effectively improve the level of civil aircraft maintenance risk management.

Discussion on Continuous Airworthiness and Maintenance of Civil Aircraft

With China’s rapid economic development,the civil aviation market’s development area has expanded.On this basis,the state has proposed more extensive and stringent civil aviation rules.Many factors can affect the civil aircraft during the real operation process,and this can have an impact on the aircraft’s regular functioning to some level.To ensure that civil aircraft remain airworthy,appropriate maintenance work must be performed on a regular basis to prevent compromising the aircraft’s safety performance.For the purpose of reference,this paper discusses the continual airworthiness and maintenance of civil aircraft.

基于LSTM-AE的民机空调热交换器性能异常检测方法

空调热交换器性能异常检测技术是快速判断民机空调系统运行状态并合理安排维修任务的关键,传统的异常检测方法难以有效处理高维时序数据,无法实现系统早期故障预警。为此,本文提出了一种基于长短期记忆网络(LSTM,long-short term memory)与自编码器(AE,autoencoder)模型的无监督异常检测方法,用以识别民机空调系统异常运行状态。首先,基于民机空调系统原始传感器参数构建表征空调热交换器性能的特征监测参数;其次,构建LSTM-AE模型进行数据特征重构并计算重构误差;最后,使用孤立森林(iForest, isolation forest)进行无监督异常监测。将本文构建的无监督异常检测方法与传统方法对比,并建立模型评估指标,验证结果表明,所构建的模型方法可以对民机空调热交换器性能异常状态进行有效检测。

基于融合系统方法的飞机复杂系统安全性分析

面对日益复杂的飞机系统,传统的安全性分析方法对复杂系统间的不安全交互行为和危险源的识别能力不足。为有效评价持续适航阶段的飞机系统安全性,提出了一种融合系统理论过程分析(system theory process analysis,STPA)和动态故障树(dynamic fault tree,DFT)的改进的STPA安全性分析方法和评价模型。模型采用STPA识别出不安全控制行为和致因因素,并将其与动态故障树分析方法相融合,以事故致因理论优化致因分析方法,计算得出不安全控制行为发生概率并确定系统潜在危险的关键致因因素。以飞机起落架系统为例进行分析验证,结果表明,改进后的STPA分析方法可以准确地对系统危险进行识别和分析,为持续适航阶段的安全性分析提供支持。

基于系统工程的民用飞机系统接口设计与控制方法研究

民用飞机系统的接口承接了功能、性能和物理空间的需求。系统接口的设计与控制是民用飞机机载系统、子系统和设备的重要设计工作之一。基于系统工程思想,以机载系统、子系统及设备接口定义和设计的相关需求为输入,以机载系统研制阶段为基础,提出了一种基于接口设计需求、层级化的接口定义与设计方法,以及同层级、上下层级间接口的控制策略。结合某民用大气数据子系统,以电气接口的设计及控制为典型案例,介绍了接口设计与控制的具体实践,为民用飞机机载系统、子系统及设备多种类型接口的设计与控制提供了工程实践性参考。

Harmony SE在民用飞机设计中的应用

随着民用飞机技术精细化和产品复杂性的提高,民用飞机设计已从传统的基于文档的系统工程转变为基于模型的系统工程,系统表达也从以文档为中心转变为以模型为中心。为进一步提高民用飞机设计中系统建模的模型质量与正确性,进而缩短设计的开发周期与成本,探究以模型驱动及验证为主导的系统工程方法在民用飞机设计领域的适用性,建立民用飞机设计的系统工程框架,用以支持民用飞机的可靠设计与高效交付。以Harmony SE建模方法为切入点,介绍其工作流程和建模思想;分析民用飞机在系统工程实践中出现的突出问题,说明Harmony SE方法在民用飞机系统工程领域的适用性,建立民用飞机设计的系统工程实践体系;以油箱增压组件为研究对象,应用实践体系开展组件级系统工程实践。结果表明,文中所提出的民用飞机设计系统工程体系和方法能够正确合理地分配设计需求并建立完整的系统模型,有助于提升现阶段民用飞机设计的效率与准确性。

关于民用飞机设计保证系统审查的思考

型号合格证申请人建立并保持设计保证系统,是我国民用航空适航规章要求的一部分,具有法律效力。由于我国民用航空工业起步较晚,在设计保证系统建设及审查方面积累的经验较少,尚未形成设计保证系统相关的咨询通告,局方和工业方在审查及表明符合性时缺少有效的技术指导。本文通过研究国内外局方对设计机构的要求,梳理了设计保证系统三大职能的核心内容及相互关系,提出了设计保证手册主要架构,总结出设计保证系统11个审查模块、28个审查要素以及对应的审查要点,提出了基于模块化的审查思路和基于过程介入的审查模式,用于帮助局方和工业方更好地开展设计保证系统建设和审查。

基于工业互联网的机载系统协同研发研究

我国民机机载产业的发展已进入由价值链低端向高端战略转型的关键时期,推进工业互联网的应用、实现机载产业数字化转型是一种不可避免的趋势。运用系统工程的方法,剖析了民机机载产业在发展过程中对工业互联网的深层次需求。通过引入体系架构方法论确立了一套适合民机机载产业特点的工业互联网体系架构。在此基础上,提出了一种基于工业互联网平台的复杂机载系统协同研发模式,有望极大提高研发效率。同时,总结了该模式在实际工程应用中的表现和成效,对比了传统研发流程,展示了其优势所在。最后,针对在推进过程中遇到的问题和挑战,提出了有针对性的建议和对策,旨在为我国民机机载产业的转型升级提供参考。

大型民机气源系统温度控制研究

作为飞机环境控制系统的重要组成部分,气源系统稳定的出口压力和温度对下游座舱压调子系统、机翼防除冰子系统及空气循环子系统等子系统的稳定工作至关重要。在发动机复杂恶劣的运转环境及传统液态控温技术无法满足控温精度的情况下,在传统PID控制基础上,提出了一种基于温度/温度变化率为控制对象的PID算法。通过仿真验证和系统台架试验验证表明,当发动机引气温度或下游用气需求温度发生变化时,该算法完全能够满足气源系统对温度、压力控制的稳定性、快速性及准确性要求,为下游用气系统提供稳定的供气来源,进而为飞机其他环控子系统的温度压力控制提供了工程参考。

SIMULATION OF BLEED AIR BEHAVIOR DURING AIRCRAFT IN FLIGHT BASED ON FLOWMASTER

Bleed air system is one of the most important components of air management system(AMS).It acts as transfer pipes responsible for air supply at high temperature and pressure.The thermal and flow performance of the bleed air system is a key issue for the design of AMS since the characteristics of air source have a great influence on the anti-ice system,the environmental control system and other downstream system in need of high temperature pressurized air.Based on the one-dimensional lumped parameter technology,a computer analysis model of bleed air system is developed in order to analyze the thermal and flow behaviors of the nodal points in the pipeline network.The simulation are performed with a given flight assignment using the analysis model,and the results verify that the system meets the design requirements.

Inspection interval optimization for aircraft composite structures with dent and delamination damage

The optimization of inspection intervals for composite structures has been proposed,but only one damage type,dent damage,has been addressed so far.The present study focuses on the two main damage types of dent and delamination,and a model for optimizing the inspection interval of composite structures is proposed to minimize the total maintenance cost on the premise that the probability of structure failure will not exceed the acceptable level.In order to analyze the damage characteristics and the residual strength of the composite structure,the frequency,energy,size,and depth of the damage are studied,and the situation of missing detection during the inspection is considered.The structural residual strength and total maintenance cost are quantified corresponding to different inspection intervals.The proposed optimization method relieves the constraints in previous simulation methods,and is more consistent with the actual situation.Finally,the outer wing of aircraft is taken as an example,and with the historical cases and experimental data,the optimization method is verified.The optimal inspection interval is shorter than the actually implemented inspection interval,and the corresponding maintenance cost is reduced by 23.3%.The result shows the feasibility and effectiveness of the proposed optimization method.

民机系统多目标维修决策方法研究

针对有限任务间隔时间内复杂民机系统的选择性维修决策问题,以最小维修、不完全维修及换件维修作为备选维修行为集,综合考虑部件维修前状态、部件役龄、维修成本、维修人员技能水平等因素,建立了复杂民机系统任务可靠度模型,并在总维修时间约束下,建立了以总维修成本最小化和任务可靠度最大化为目标的多目标维修决策模型,设计改进多目标粒子群算法对提出的决策模型进行了求解。通过案例分析验证了模型的有效性,并分析了引入不完全维修对Pareto解集的影响。结合模型求解结果可知,通过合理的分配维修资源,可有效提高维修资源的利用效率,在保障安全性的基础上实现维修经济性最大化。

面向适航符合性的智能航电系统认证研究进展

民用飞机航电系统引入人工智能/机器学习技术会带来可信性、不确定性和可解释性等问题,有必要通过有效的符合性方法向公众与利益攸关方证实智能航电系统的适航安全性。首先,分析了智能航电系统的等级分类和应用现状,阐述了现有指南和标准的适用性;然后,基于对当前研究成果的梳理,总结了智能航电系统认证框架实施流程及其技术细节;最后,给出智能航电系统在全生命周期各个阶段的符合性验证要求及实现方法建议,评估了符合性验证对现有适航体系的影响,为民用飞机智能航电系统的设计与认证提供了参考依据。

基于运行场景的结构化民机系统功能需求捕获方法

基于场景的需求捕获方法存在需求偏差和缺失、可追溯性和一致性不足等问题。本文基于模型的系统工程(MBSE,model-based system engineering)在体系结构框架下建立可视化视点模型,形成“运行场景—功能需求”过程的映射关系,提出基于运行场景的结构化民机系统功能需求捕获方法。以平视显示器(HUD,head-up display)系统为例,构建多维度、多层次场景和多视图体系结构模型,实现系统功能需求开发的“正向设计”,验证了该方法的可操作性和有效性。该方法对提升民机系统需求分析能力及系统开发思路具有重要参考意义。

面向岗位能力培养的民用飞机机型知识训练系统开发

针对机型知识缺少有效训练手段的现状,同时解决交通管理专业学生对飞机系统和飞机性能知识的掌握不均衡、欠缺的问题,基于岗位能力需求,为高年级本科生开发了一款民用飞机机型知识辅助训练系统,该系统分为飞机系统和飞机性能两大模块,集自主学习、测试训练、考核评价于一体,可满足交通管理专业学生对飞机系统和飞机性能知识的培养目标。此外该软件增加了国产民机“特色学习”模块。通过该系统的训练,学生可自选题库,自主设置题目,由被动变为主动,系统化学习机型知识,提高了机型理论掌握能力。

基于ARINC825的民机电源系统通信架构设计与分析

民用飞机电源系统的通信架构是系统通信网络的核心,通信架构根据电源设备的通信需求及设备数量进行总线的选择与线路的设计。在对多种飞机总线进行研究后发现,ARINC825总线较适合用于搭建国产大飞机的电源系统通信架构,完全采用ARINC825总线设计可以攻克飞机电源系统通信架构中常用的TTP/C总线产生的技术不透明等难题。分析了ARINC825总线与其他常用总线各自的优势与缺点后,设计了一种完全基于ARINC825总线的电源系统通信架构,从数据传输、通信成本、通信安全三个方面着手论述了该新型通信架构在理论上的可行性。所提通信架构对于总线负载率、子网花费的板卡价格和通信误码率这三重指标进行计算,其结果在通信的实时性、可靠性和经济性等各方面都有较大的提升,为民用飞机电源系统的数字化、智能化发展提供了帮助。