【作者】 龚正；

【导师】 沈宏良；

【作者基本信息】 南京航空航天大学 ， 流体力学， 2007， 硕士

【摘要】 具有过失速机动能力的现代战斗机将在近距离空战中取得极大的空中优势。过失速机动能力已成为下一代战斗机设计的必需要求。过失速大迎角飞行状态下,非定常气动力、运动惯性耦合、控制系统非线性等因素综合作用,使飞行动力学系统呈现高度的非线性、非定常特性,常规的飞行动力学小扰动线化分析方法不再完全适用于过失速机动特性的研究。如何建立大迎角非定常气动模型,分析非线性飞行动力学特性,并设计大迎角下的飞行控制律,这是现代战斗机设计中必须解决的飞行力学、空气动力学、飞行控制学科交叉耦合的关键技术问题,其研究具有重要的理论意义和工程实用价值。本文采用了神经网络与模糊逻辑的方法,根据非定常风洞的实验数据,建立了全量六自由度的非线性、非定常的大迎角气动力模型,并且以分支分析与突变理论为核心,分析非定常气动力对飞机飞行特性的影响。将分支裁剪技术与特征结构配置方法相结合,设计了闭环三目标分支裁剪的大迎角控制律。基于XML建模语言,建立了新一代具有高可扩展性、通用性、跨平台特点的飞行仿真模型,开发了飞行仿真软件。经过数值仿真与人在环飞行模拟,验证了非定常气动力的影响与控制律设计的有效性。综合上述研究成果,本文设计了非线性飞行动力学分析与控制律设计一体化软件框架,在开发完成气动与飞行动力学建模、飞行动力学分析、飞行控制律设计相应软件模块的基础上,将其有机的结合为一个整体,为非线性飞行动力学相关问题的研究提供了强大的技术和软件手段,研究成果可应用于新一代及下一代战斗机的设计。更多还原

【Abstract】 The modern fighter aircrafts with the post stall maneuver ability will own great advantage in the close air battle. The post stall ability has been the basic requirement for the next generation of the fighter aircrafts. In the state of high Angel of Attack (AOA) and post stall maneuver, with the effect of the nonsteady aerodynamic forces, the motion inertia coupling, the nonlinear factors in the Flight Control System (FCS), the flight dynamic system shows the behaviors of nonsteady and nonlinear. The traditional research way, based on linearization and small disturbance, is invalid to study the behaviors of aircraft in the post stall maneuver. How to model the aerodynamic forces in the high AOA, how to analyze the character of the nonlinear model, how to design the flight control system in the high AOA, these are the key technique problems in the cross fields of the flight dynamics, aerodynamics and flight control. These researches have great value in both the theory and the engineering field.Based on the nonsteady experiments in the wind tunnel, the article uses the Artificial Neural Network and Fuzzy Logic to establish the full value and six degree of freedom flight dynamics model. With Bifurcation Analysis and Catastrophe Theories Method (BACTM), the impact of nonsteady and nonlinear aerodynamic forces on the flight dynamics is analyzed. Fusing the Bifurcation Tailor and the Eigenstructure Assignment technique, the close-loop three-target bifurcation tailor is used in the design of the high AOA flight control system. Based on the XML model language, the flexible, general and cross-platform flight dynamic model is established, the flight simulation software is developed. The script simulation and man-in-loop simulation show the effect of the nonsteady aerodynamics and the effect of the flight controller design. Combining all these techniques above, the integrative software frame is established. The modeling, analysis and control software are combined to form as a whole. The software frame provides a powerful technique and software method to do nonlinear flight dynamics research. The work can be applied to the design of the next generation fighter aircrafts.更多还原