Cooperative formation control of multiple aerial vehicles based on guidance route in a complex task environment

In recent years, formation control of multi-agent has been a significant research subject in the field of cooperative control. However, previous works have mainly concentrated on formation control for simple point-mass model and linear model. In contrast, this paper presents a novel cooperative algorithm for multiple air vehicles formation control, which aims to devise a control strategy based on guidance route to achieve precisely coordinated formation control for a group of fixed-wing aircraft in a complex task environment. The proposed method introduces the leader-follower structure for effective organization of the multi-agent coordination. Moreover, the Partial Integrated Formation and Control (PIFC) is adopted to design the control law for Guidance-Route based Formation Control (GRFC). Additionally, the proposed approach designs two guidance-route generation strategies for two special situations to demonstrate the effectiveness of GRFC in complex task environments. Theoretical analysis reveals that the proposed control protocol for guidance command can ensure the overall stability and tracking accuracy of the system. Numerical simulations are performed to illustrate the theoretical results, and verify that the proposed approach can achieve coordinated formation control precisely in a complex task environment.     

波音飞机机身蒙皮划痕浅析

飞机蒙皮划痕问题已成为飞机维护中最为突出的结构问题之一。本文结合波音公司发布的维护/维修方案和服务通告SB-737-53A1262、SB-737-53A1289,对飞机维修中划痕损伤的问题进行探讨。     

膜分离器及其机载应用

为了满足飞机放火防爆要求，膜分离器作为机载油箱惰化系统的关键部件在国外军、民机已经装机使用，在国内膜分离器处于研制阶段，正逐步向军、民用飞机推广应用。分析了国内外现状，对膜分离器工作机理进行了阐述，详细论述了膜分离器研制过程中涉及到的膜材料、膜制备工艺、膜分离器，总结了影响膜分离器性能的主要参数；进行了膜分离器在机载惰化中应用的试验研究，总结了研发和应用中得到的经验，有利于膜分离器今后的研发和机载惰化中的应用。     

飞机等表速运动方程与稳态爬升参数计算

为了揭示等表速飞行的内在机理,建立了飞机等表速运动方程,提出了等表速爬升运动参数计算方法。对比等表速和等真空速爬升公式,提出了功率因子的概念,以反映飞机等表速与等真空速爬升所需单位剩余功率之间的关系。针对等表速等推力、等表速等梯度、等表速等升降速度3种典型爬升方式,应用飞机等表速运动方程给出了稳态运动参数计算方法。计算结果表明,3种爬升方式均存在稳态爬升剖面,稳态运动参数与表速呈一一对应关系。     

Process of establishing design requirements and selecting alternative configurations for conceptual design of a VLA

In this study, a process for establishing design requirements and selecting alternative con-figurations for the conceptual phase of aircraft design has been proposed. The proposed process uses system-engineering-based requirement-analysis techniques such as objective tree, analytic hier-archy process, and quality function deployment to establish logical and quantitative standards. Moreover, in order to perform a logical selection of alternative aircraft configurations, it uses advanced decision-making methods such as morphological matrix and technique for order prefer-ence by similarity to the ideal solution. In addition, a preliminary sizing tool has been developed to check the feasibility of the established performance requirements and to evaluate the flight perfor-mance of the selected configurations. The present process has been applied for a two-seater very light aircraft (VLA), resulting in a set of tentative design requirements and two families of VLA configurations: a high-wing configuration and a low-wing configuration. The resulting set of design requirements consists of three categories: customer requirements, certification requirements, and performance requirements. The performance requirements include two mission requirements for the flight range and the endurance by reflecting the customer requirements. The flight performances of the two configuration families were evaluated using the sizing tool developed and the low-wing configuration with conventional tails was selected as the best baseline configuration for the VLA.     

Correction method of airfoil thickness effect in hinge moment calculation of a folding wing

The influences of airfoil thickness on the aerodynamic loading distribution and the hinge moments of folding wing aircraft are presented in this work. The traditional panel method shows deficiencies in the calculation of folding wing’s hinge moments. Thus, a thickness correction strategy for the aerodynamic model with CFD results is proposed, and an aeroelastic flight simulation platform is constructed based on the secondary development of ADAMS. Based on the platform, the developed aerodynamic model is verified, then the flight-folding process of the folding wing aircraft is simulated, and the influences of airfoil thickness on the results are investigated. Results show that the developed aerodynamic model can effectively describe the thickness effect of the folding wing. Airfoil thickness, which cannot be considered by the panel method, has a great influence on the hinge moments during the folding process, and the thickness correction has great significance in the calculation of folding wing’s hinge moments.     

基于EGView的SR20飞机的发动机爆震分析

基于EGView软件对SR20飞机出现的多起发动机CHT异常升高故障进行了分析，结果表明出现了早燃引发的爆震，进一步对爆震发生的几率以及如何减小爆震的强度和持续时间进行了研究，并就该机型在运行中减少爆震的发生提出了建议。     

一种基于模式寻优的舰载机实时回收方法

为了解决舰载机的回收决策问题，提出一种基于模式寻优的舰载机实时回收方法。通过对典型回收模式的计算分析，寻求最佳的回收模式，解决舰载机回收过程中通用因素带来的回收决策问题。在此基础上，提出一种考虑优先级的时间域区间集算法，解决舰载机回收过程中随机因素带来的回收决策问题，即在既定的回收群体下，寻求最佳的回收序列。仿真结果表明，基于模式寻优的舰载机实时回收方法能够处理复杂多变的回收限制因素，得到合理可行的回收决策方案。     

复合材料飞机闪电防护设计

飞机的闪电防护设计是一项涉及到多个专业的综合性技术,具体来说,飞机结构、飞控、燃油、航电等专业都必须在设计时考虑闪电防护.随着复合材料技术的发展,运用全复合材料进行通用飞机的设计制造已越来越广泛.由于复合材料和金属材料的差异性,其闪电防护设计具有完全不同的特点.本文根据国内外研究发展趋势,阐述复合材料飞机的闪电防护设计技术以及适航验证的方法.     

Design of aircraft structures against threat of bird strikes

In this paper, a method to design bird-strike-resistant aircraft structures is presented and illustrated through examples. The focus is on bird strike experiments and simulations. The explicit finite element software PAM-CRASH is employed to conduct bird strike simulations, and a coupled Smooth Particles Hydrodynamic (SPH) and Finite Element (FE) method is used to simulate the interaction between a bird and a target structure. The SPH method is explained, and an SPH bird model is established. Constitutive models for various structural materials, such as aluminum alloys, composite materials, honeycomb, and foam materials that are used in aircraft structures, are presented, and model parameters are identified by conducting various material tests. Good agreements between simulation results and experimental data suggest that the numerical model is capable of predicting the dynamic responses of various aircraft structures under a bird strike, and numerical simulation can be used as a tool to design bird-strike-resistant aircraft structures.