近空间飞行器机翼的结构损伤分析及自适应减损控制技术研究

Due to the effects of hypersonic flows, the airfoils of a near space vehicle with hypersonic speed may suffer structural continuous buffeting or structural damage, and the accumulation of the damage may cause a flight disaster. It is very difficult to identify, modeling and control the structural damage for the near space vehicle’s airfoils. Especially, due to the harsh flight environment, it makes there exist more uncertainties of structural reliability, damage modeling, and control during the analysis process. In order to ensure the structure reliability and extend the life of the vehicle throughout the flight envelope, this application is carried out to study structure damage and adaptive structural damage mitigating control for the near-space vehicle’s airfoils. During the study period, the structural reliability and failure rate based on a total probability stress-strength interference model are analyzed by analyzing the structure force loads of the airfoils, and a dynamical structural damage model of the airfoil based on FASTRAN model is established. Then, a multi-objective optimization function is constructed to achieve the best balance between the mitigating control of the airfoils and the vehicle’s flight performance. Finally, fast adaptive mitigating control is studied based on a novel sliding mode control with unidirectional auxiliary surfaces and a modified approaching law with Terminal attractor and power term. The work of this project will provide the basis of theory and methodology to solve the damage mitigating control system design for the near-space vehicles’ airfoils.

近空间飞行器在高速飞行时由于受到高超声速气流的影响，会引起机翼的结构持续抖振或结构损伤，损伤的持续积累可能会导致飞行灾难。近空间飞行器的机翼结构损伤具有难识别、难建模和难控制的特点，尤其突出的是结构部件损伤难以准确建模，而且考虑到恶劣的飞行环境，更增加了可靠性分析、损伤建模分析和控制的不确定性。为了保证飞行器在整个飞行包线内的结构可靠性、延长使用寿命，本申请开展关于近空间飞行器机翼的结构损伤的分析和自适应减损控制的研究。其中通过分析机翼结构受力载荷，基于全概率应力-强度干涉模型分析结构可靠性和失效率，基于FASTRAN模型建立机翼结构损伤的动态模型，然后构造多目标优化函数，使飞行器性能和机翼减损控制之间达到最佳平衡，并基于单向辅助面滑模和基于Terminal吸引子与幂次型改造的趋近律开展快速自适应减损控制研究，为解决近空间飞行器机翼结构减损控制设计和工程实现提供理论和方法的依据。

近空间高超声速飞行器是未来空天战场上克敌制胜的利器，研究和掌握其相关技术对于我国空天环境安全具有重大的战略意义。由于高超声速气流会引起机翼的结构持续抖振或结构损伤，且损伤的持续积累可能会导致飞行灾难。为了保证飞行器在整个飞行包线内的结构可靠性，并延长使用寿命，本项目研究了近空间飞行器的机翼结构损伤和减损控制问题。主要研究内容如下：.(1)完成近空间飞行器机翼结构强度可靠性分析，基于结构可靠性和应力强度理论，对机翼关键部件的受力情况和结构可靠性进行了分析。.(2)完成近空间飞行器机翼结构损伤特性分析，建立了翼梁根部损伤模型，分析了飞行器各状态对损伤演化的影响。.(3)完成基于优化控制指令的近空间飞行器机翼减损控制，通过使用Bezier曲线构造控制指令信号的约束曲线，实现机翼关键部件的减损控制。.(4)完成基于单向辅助面滑模的近空间飞行器机翼减损控制，将翼梁根部的损伤量与损伤变化率反馈至趋近律，随着损伤量的变化在线调节系统的飞行控制。.(5)完成近空间飞行器的机翼非线性损伤模型的建立，分析了飞行器飞行动态变量对机翼翼梁根部损伤特性的影响，并确定影响非线性损伤的关键变量。.(6)完成近空间飞行器基于预设性能的机翼减损控制器的设计，进行应力分析确定损伤最易累积的机翼截面，结合损伤模型和飞行器模型设计减损控制器，达到减损和保障飞行性能的双重目的。.(7)完成近空间飞行器机翼的最优预测减损控制器设计，根据损伤量在线调整权值来权衡减损和飞控之前的关系，降低所累积的损伤。.(8)完成近空间飞行器基于性能函数的最优预测机翼减损控制器的设计，将性能函数引入目标函数，在减损的同时进一步提升了飞行系统的性能。.(9)完成近空间飞行器机翼颤振模型的建立，考虑飞行动态的变化与机翼颤振的相互影响，研究机翼颤振引起的损伤，进而设计预测控制器有效抑制颤振并延缓损伤。