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161.
ZHAO Hongshenga XU Xiaohaob ZHANG Juna ZHU Yanboa YANG Chuansenc HONG Shengd aSchool of Electronics Information Engineering Beihang University Beijing China bCollege of Air Traffic Management Civil Aviation University of China Tianjin China cCollege of Civil Aviation Nanjing University of Aeronautics Astronautics Nanjing China dSchool of Reliability System Engineering China 《中国航空学报》2011,(3):329-336
Flight technical error (FTE) combined with navigation system error (NSE) is the main part of total system error (TSE) in performance based navigation (PBN).The implementation of PBN requires pre-flight prediction and en-route short-term dynamical prediction of the TSE.Once the sum of predicted lateral FTE and NSE is greater than the specified PBN value,the PBN cannot operate.Thus,accurate modeling and thorough analysis of lateral FTE are indispensible.Multiple-input multiple-output (MIMO) lateral track control system of a transport aircraft is designed using linear quadratic Gaussian and loop transfer recovery (LQG/LTR) method,and the lateral FTE of a turbulence disturbed approach operation is analyzed.The error estimation mapping function of latera FTE and its bound estimation algorithm are proposed based on singular value theory.According to the forming mechanism of lateral FTE,the algorithm considers environmental turbulence fluctuation disturbance,aircraft dynamics and control system parameters.Real-data-based Monte-Carlo simulation validates the theoretical analysis of FTE.It also shows that FTE is mainly caused by turbulence fluctuation disturbance when automatic flight control system (AFCS) is engaged and would increase with escalating environmental turbulence intensity. 相似文献
162.
Challenges of future aircraft propulsion: A review of distributed propulsion technology and its potential application for the all electric commercial aircraft 总被引:12,自引:0,他引:12
This paper highlights the role of distributed propulsion technology for future commercial aircraft. After an initial historical perspective on the conceptual aspects of distributed propulsion technology and a glimpse at numerous aircraft that have taken distributed propulsion technology to flight, the focal point of the review is shifted towards a potential role this technology may entail for future commercial aircraft. Technological limitations and challenges of this specific technology are also considered in combination with an all electric aircraft concept, as means of predicting the challenges associated with the design process of a next generation commercial aircraft. 相似文献
163.
The huge and rapid progress in electric drives offers new opportunities to improve the performances of aircraft at all levels:fuel burn,environmental footprint,safety,integration and production,serviceability,and maintainability.Actuation for safety-critical applications like flight-controls,landing gears,and even engines is one of the major consumers of non-propulsive power.Conventional actuation with centralized hydraulic power generation and distribution and control of power by throttling has been well established for decades,but offers a limited potential of evolution.In this context,electric drives become more and more attractive to remove the natural drawbacks of conventional actuation and to offer new opportunities for improving performance.This paper takes the stock,at both the signal and power levels,of the evolution of actuation for safety-critical applications in aerospace.It focuses on the recent advances and the remaining chal lenges to be taken toward full electrical actuation for commercial and military aircraft,helicopters,and launchers.It logically starts by emphasizing the specificity of safety-critical actuation for aero space.The following section addresses in details the evolution of aerospace actuation from mechanically-signaled and hydraulically-supplied to all electric,with special emphasis on research and development programs and on solutions entered into service.Finally,the last section reviews the challenges to be taken to generalize the use of all-electric actuators for future aircraft programs. 相似文献
164.
根据当前IT应用的普及情况,分析了大中型企业中网络资源管理存在的问题,研究了网管软件的相关技术并设计了一套符合当前应用需求的分布式管理架构的应用型网管系统。该系统不但可监测各类操作系统的性能,还可对数据库、WEB服务等应用服务器的性能进行监控。结合网管软件的发展动态,展示了该应用型网管系统的工程应用价值。 相似文献
165.
S.A. Pulinets 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009
The concept of the Global Electric Circuit (GEC) provides an explanation of the existence of a vertical atmospheric electric field and coupling between the ground and ionosphere. Presently, ionospheric physics pays more attention to electric fields and coupling processes in the polar and auroral regions, whereas in other areas the potential difference between the ground and ionosphere usually is not taken into account. Regional processes exist, however, that are able to significantly affect the GEC parameters and through modification of the ionospheric potential to create plasma density irregularities of different scales within the ionosphere. One such source of ionosphere modification is air ionization in the vicinity of active tectonic faults, which takes place due to increased radon emanation. This paper considers the process of local modification of the GEC and corresponding ionospheric variability due to tectonic activity. 相似文献
166.
中国空中交通流量管理系统的组织设计——以工作地点为基础的多层次人机组织设计的应用 总被引:3,自引:2,他引:1
描述了人机系统的基本组成:人的控制系统和技术控制系统。由于控制对象的复杂性,将其整个活动划分为多个子活动,位于不同的工作地点,在每个地点建立相应的人机系统,这就构成了以工作地点为基础的人机系统。依据工作地点之间的联系,确立人机的一现多样性:集中式、分散式、层次式。根据目前中国空中交通流量管理的现状,参考以工作地点为的人机系统设计方法,建立多层次的中国流量管理组织结构,实现有效的人机合作,以此协调各方面的活动与关系,保证空中交通安全有序。 相似文献
167.
区域空中交通流量控制研究 总被引:6,自引:0,他引:6
运用排队论思想,结合区域控制的特点建立了区域流量控制模型,分析了郑州区域管制中心实施流量控制的实际效果,研究结果表明,仅考虑单独区域流量控制,将使航班延误的不利影响逐级放大,理想的流量控制应该全面考虑所有受影响的区域,合理地选择控制时段和控制间隔,最大限度地利用空域资源,减少航班延误,保证空中交通的安全畅通。 相似文献
168.
Are space agencies able to reform the way they are organized? Attempts to reduce the time it takes to conceive new systems and adapt project management while fostering innovation have so far shown mixed results. In this paper, we describe some of the intellectual, strategic and organizational challenges the agencies are about to face in the coming years: managing the ever growing complexity of space systems; defining a knowledge-based strategy as the basis of a renewed organization; and assuming a central role in the innovation process in relation to industry. This thesis is illustrated with a case study of the CNES Microsatellite Myriade program. 相似文献
169.
针对科研工作量考核中的考核标准确定及考核结果的分析等问题进行了研究,主要包括:根据分层抽样原理,采用Brewer方法设计了制订考核标准值的抽样调查方案;确定科研工作量的分布情况以及有关特征值,掌握学校科研工作的现状;利用方差分析法,确定不同职称系列承担科研工作的差异例用回归分析预测法和干涉因子灰色预测法,掌握科研工作量的变化情况及和学校政策的相互关系。一实际应用结果表明,该方法能比较客观地确定科研工作量的考核标准,同时为学校制订相关政策提供了依据。 相似文献
170.