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《Journal of The Franklin Institute》2001,338(2-3):113-132
This paper describes an investigation of dive recovery maneuvers of a jet fighter aircraft capable of flying at angles of attack in the post-stall region. In a dive recovery maneuver, the pilot attempts to return the aircraft to level flight at an airspeed such that level flight can be maintained afterward. This maneuver is needed after either an intentional dive or an unintentional dive, or as the terminal recovery stage from some unusual attitude, namely, combination of extremely low airspeed and very high flight path angle. The optimization criterion is the minimization of the maximum loss of altitude during the dive recovery; hence, the optimization problem is a minimax problem of optimal control. The flight dynamics model accounts for all of the factors necessary to accurately characterize the aircraft motion.The results show that the optimal dive recovery trajectories consist of one to three segments, depending on the initial speed and flight path angle. For relatively high initial speed, the optimal trajectory consists of a single segment: a pitch-up at the limiting load factor. For very low initial speed, the optimal trajectory consists of two segments: a supermaneuver flown at very large angles of attack, followed by a pitch-up at the limiting load factor. For unusual attitude recovery from the combination of very low initial speed and very high initial flight path angle, the optimal trajectory consists of three segments: a dive initiation segment, followed by a supermaneuver at very large angles of attack, followed by a pitch-up at the limiting load factor. For aircraft without supermaneuver capability, the supermaneuver segment is to be replaced by a maximum angle of attack segment. The paper concludes with a discussion of the design benefits accrued via supermaneuver capability as well as the operational benefits accrued via afterburner usage. 相似文献
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舱位控制在航空收益管理处于核心地位。已有的研究成果主要集中于航空客运方面,而对航空货运舱位控制方面的研究比较少。本文主要采用动态规划方法建立了单航段条件下的航空货运舱位动态优化控制的模型,由该模型可得出航空货运舱位动态优化控制的策略。最后通过算例说明该模型具有实用性,并能提高航空公司的货运收益。 相似文献
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飞行仿真系统为民机设计动态验证提供了重要的支持,本文以一般民用客机为研究背景,从民用飞机飞行仿真系统的模型分类、飞行仿真系统模型的通用建模规范、飞行仿真系统模型的组成及其互联关系等方面进行了研究。 相似文献
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利用意愿调查价值评估法的相关原理,选取天津滨海机场、北京首都机场的旅客为对象,调查了旅客的低碳意识和航空碳税支付意愿.结果表明: 航空旅客具有一定的低碳意识,但是收入水平、机票报销比例和年龄对其支付碳税意愿有显著影响;航空旅客不愿意支付碳税主要有3个原因: 混淆碳税和燃油附加费、对碳减排责任主体认识存在偏差、不信任政府将航空碳税用于碳减排.为了未来碳税政策有效实施,建议加强对低碳和碳税相关知识的科学宣传、航空碳税征收要兼顾人们的支付能力、按照旅客飞行公里数征收碳税以及增加碳税使用和管理方面的透明度. 相似文献
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《Journal of The Franklin Institute》2021,358(18):9721-9740
The buffeting phenomenon can lead to long-term damage in aeroelastic bodies due to fatigue. It can also restrict the maneuverability of aircrafts. In this work, the buffeting problem of the twin-tails of a fighter aircraft is tackled. A nonlinear model of the twin-tails is utilized, and the buffeting load is simulated using a wind disturbance model that combines discrete wind gust and Von-Karman wind turbulence. An integral sliding mode controller is developed to suppress the vibrations of the twin-tails. Simulation studies demonstrate the effectiveness of the sliding mode controller at suppressing the vibrations the twin-tails. 相似文献
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This paper focuses on automatic climbing control methods for large civil aircraft. The key technique is how to design automatic flight control laws that meet the requirements of flight performance indexes and have good characteristics of restraining various disturbances. The classical engineering methods are used to solve the above problem. Based on the aerodynamic data of Boeing707, a nonlinear model of large civil aircraft is established. Linear models which are divided into longitudinal and lateral equations are obtained by trim and linearization. The design of longitudinal control laws uses C? criterion, three climbing schemes including pitch control mode, vertical velocity control mode and altitude control mode are designed and mutually compared. For lateral control problem, by the feedback angle of sideslip, the bank attitude control with good effect is achieved. The simulation results indicate the designed control laws can meet the requirements of performance indexes, and have satisfied characteristics of anti-gust disturbance. 相似文献
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加强民机产业链建设是提升研发实力,促进行业发展,培养人才队伍的主要途径。民机主制造商对系统供应商进行管理,引领着飞机设计和生产的全过程。航空公司作为民机的运营者,创造利润并反馈客户需求。同时,民机产业的发展与政治利益和国际适航标准密切相关,使得政府在资金、政策、外交、适航审定等方面的工作显得尤为重要。因此,合理认识三类主体在民机产业链中的角色和相互关系,对推动产业链建设将起到关键作用。 相似文献
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飞行仿真系统是现代飞行器设计与研发的重要工具,是整个飞行器进行飞行模拟的重要数据源,可以为飞行器设计的动态验证提供重要支持。为了使模拟器能够尽量逼真地模拟飞机的飞行,需要建立精确的飞行仿真系统。对飞行仿真系统设计进行了研究,介绍了飞行仿真系统组成,给出了飞行仿真系统架构,阐述了飞行仿真系统功能。 相似文献
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在民用飞机机身结构设计中,舱门/门框结构设计是飞机设计的难点之一。舱门/门框可以根据其功能、大小、受力形式的不同分为不同的类型,在其结构设计时,需考虑舱门自身特点,优化其受力形式,在满足其功能的前提下,节省结构重量。本文通过对比现在两大航空公司的典型的货舱门设计,结合飞机设计实际经验以及相关资料,阐述不同类型舱门的设计理念和力学原理,为航空器结构设计师们拓宽思路。 相似文献
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北京市公共交通满意度物元评价 总被引：1，自引：0，他引：1
根据乘客对于公交服务的核心需求,建立了公共交通满意度评价指标体系,提出了基于变异系数法确定指标权重的公共交通乘客满意度物元评价模型,以此为基础,根据对公共交通乘客满意度问卷调查所得数据进行实证分析,得到北京市公共交通乘客的满意度为"一般"水平。 相似文献
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技术创新系统可分为产品创新系统和工艺创新系统。基于二象对偶理论,将产品创新(工艺创新)系统设计为由以创新绩效为表征的状态子系统和以创新资源协同为度量方法的行为子系统构成的二象系统。分析了技术创新系统子系统的二象特征,构建了技术创新系统协同度模型,采用1995-2008年航空航天器制造业科技活动数据,对航空航天器制造业技术创新系统进行协同度测量及分析。结果表明,我国航空航天器制造业技术创新系统协同发展水平总体不高。其中,提升工艺创新资源协同水平将成为未来航空航天器制造业技术创新系统协调发展的重要任务。 相似文献