Design,modeling, and control of morphing aircraft:A review

A morphing aircraft can adapt its configuration to suit different types of tasks, which is also an important requirement of Unmanned Aerial Vehicles(UAV). The successful development of an unmanned morphing aircraft involves three steps that determine its ability and intelligent: configuration design, dynamic modeling and flight control. This study conducts a comprehensive survey of morphing aircraft. First, the methods to design the configuration of a morphing aircraft are presented and analyzed...     

Optimization of multi-element airfoil settings considering ice accretion effect

Almost half of all flight accidents caused by inflight icing occur at the approach and landing phases when high-lift devices are deployed. The present study focuses on the optimization of an ice-tolerant multi-element airfoil. Dual-objective optimization is carried out with critical horn-shaped ice accumulated during the holding phase. The optimization results show that the present optimization method significantly enhances the iced-state and clean-state performance. The optimal multi-element airfoil has a larger deflection angle and wider gap at the slat and the flap compared with the baseline configuration. The sensitivity of each design parameter is analyzed, which verifies the robustness of the design. The design is further assessed when ice is accreted during the approach and landing phases, which also shows performance improvement.     

飞行器制导控制一体化编队控制器设计

针对主从式结构飞行器协同编队控制问题，以侧滑转弯飞行器为研究对象，采用制导控制一体化(Integrated guidance and control, IGC)方法设计编队控制器。首先在惯性坐标系中定义相对运动坐标系，建立相对运动模型，结合飞行器动力学模型，得到全状态制导控制一体化模型；然后采用反演方法，结合滑模变结构与神经网络自适应理论设计了编队控制器，并证明了控制系统稳定性；最后在高速情况下进行了六自由度数值仿真，对比了IGC设计方法与分离设计方法的控制性能。仿真结果表明所设计的IGC控制器能够快速精确地对期望编队队形进行构建与保持，并且较分离设计方法具有优越性。     

LED照明技术在飞机外部照明系统中的应用分析

外部照明是飞机照明系统的一个重要组成部分,在飞机起飞、巡航、着陆等过程中为其提供空中信息。外部照明对灯具的性能要求很高,如高强度、抗振动、长寿命、高可靠性等,且不同灯具实现不同功能,有特定的光分布要求,而采用传统光源的外部照明难以满足这些不断提高的技术要求。LED照明具有高亮度、低功耗、长寿命等技术优势,有助于促进飞机外部照明技术更好的发展。对LED照明技术及飞机外部照明系统的特点进行了分析,探讨了LED照明技术在飞机外部照明系统中的应用优势与前景。     

冰晶粒子运动过程中的相变特性

针对冰晶在温暖环境下运动时固液汽耦合的相变现象，基于欧拉法建立了冰晶粒子的运动相变模型和计算方法。计算了冰晶粒子在强迫对流环境下的融化相变过程，与实验结果对比验证了运动相变模型和计算方法的准确性。针对NACA0012翼型计算了冰晶绕流运动时的热力学特性，得到了冰晶粒子到达撞击表面时的融化状态与收集系数。研究了冰晶粒径大小、初始球形度、气流相对湿度和温度对运动相变的影响。结果表明：冰晶粒子运动相变模型可以有效地评估冰晶结冰风险，冰晶粒子的融化速率主要取决于粒子直径、球形度、气流温度、湿度等因素，环境温度为288 K时冰晶粒子的融化时间为27.5 s，而相同条件下环境温度为302 K时的融化时间仅有5.2 s。     

Surrogate role of machine learning in motor-drive optimization for more-electric aircraft applications

Motor drives form an essential part of the electric compressors, pumps, braking and actuation systems in the More-Electric Aircraft (MEA). In this paper, the application of Machine Learning (ML) in motor-drive design and optimization process is investigated. The general idea of using ML is to train surrogate models for the optimization. This training process is based on sample data collected from detailed simulation or experiment of motor drives. However, the Surrogate Role (SR) of ML may vary for different applications. This paper first introduces the principles of ML and then proposes two SRs (direct mapping approach and correction approach) of the ML in a motor-drive optimization process. Two different cases are given for the method comparison and validation of ML SRs. The first case is using the sample data from experiments to train the ML surrogate models. For the second case, the joint-simulation data is utilized for a multi-objective motor-drive optimization problem. It is found that both surrogate roles of ML can provide a good mapping model for the cases and in the second case, three feasible design schemes of ML are proposed and validated for the two SRs. Regarding the time consumption in optimizaiton, the proposed ML models can give one motor-drive design point up to 0.044 s while it takes more than 1.5 mins for the used simulation-based models.     

Downwash modelling for three-lifting-surface aircraft configuration design

This paper introduces a semi-empirical model to predict the downwash gradient at the horizontal tail of a three-lifting-surface aircraft. The superposition principle applied to well established formulations valid for two lifting surfaces is not a reasonable approach to calculate the downwash of a canard-wing-tail layout, and this paper demonstrates that such a basic technique leads to incorrect results. Therefore, an ad hoc prediction model is proposed that considers the combined nonlinear effec...     

基于气凝胶的防隔热一体化材料研究进展北大核心CSCD

新型高速飞行器的快速发展对热防护系统提出了更高要求,基于气凝胶的防隔热一体化材料对提升热防护系统的防隔热性能和结构效率有重要意义。本文基于防热层材料的不同,分类概述了基于气凝胶的防隔热一体化材料的研究进展、结构形式和性能特点,并简要阐述未来防隔热一体化材料发展需要解决的问题。     

Optimum alternate material selection methodology for an aircraft skin

Weight penalty has been a challenge for design engineers of aerospace vehicles. Today’s high-efficiency combat aircraft undergoes intense stress and strain during flying missions, which require stronger and stiffer materials to retain structural integrity. Though metallic materials have been successfully used for the construction of aircraft structures and components, metals still have a low strength-to-weight ratio. This paper aims to develop an alternate optimised material selection methodolog...