考虑气动加热和变截面惯性矩的高超声速飞行器建模与分析

由于高超声速飞行器弹性机体/发动机的高度一体化设计,使得此类飞行器的动力学建模与控制较为复杂,而作为控制的基础以及面向控制的总体优化设计都需要建立高精度的动力学模型。首先,建立了考虑气动加热和变截面惯性矩影响的高超声速飞行器自由梁结构弹性模型,分析了气动加热和变截面惯性矩对飞行器振型的影响,得出了气动加热对振型影响非常小且振型引起的攻角变化很小,变截面惯性矩对飞行器的振型影响较大且振型引起的攻角变化较大的结论。然后,建立了考虑气动加热和变截面惯性矩影响的自由梁高超声速飞行器动力学模型,对考虑气动加热和忽略气动加热、恒截面惯性矩和变截面惯性矩对应的动力学模型进行了零极点分布对比分析,得出了气动加热对飞行器的纵向动态特性影响很小,变截面惯性矩自由梁对应的高超声速飞行器在特征点处开环不稳定性更大和非最小相位行为约束变弱的结论。

Modeling and Analysis of Hypersonic Vehicle Considering Variable Cross-Section Moment of Inertia and Aerodynamics Heating

Hypersonic vehicle dynamics modeling and control are much more complicated due to its highly integrated design of flexible body and engine.A high fidelity dynamic model is required for the control system design as well as the conceptual design.Firstly the free-free beam elastic model considering variable cross-section moment of inertia and aerodynamic heating is set up for hypersonic vehicle.The effects of aerodynamic heating on the vibration mode,as well as the resulting change of attack angle is vevy small,while the variable cross-section moment of inertia has greater impact on vibration mode and the resulting change of attack angle is larger.Then the free-free beam dynamics model for hypersonic vehicle considering variable cross-section moment of inertia and aerodynamic heating is established.The zeros/poles distribution are compared and analyzed between the free-free beam dynamics models with aerodynamic heating considered or not and invariable or variable cross-section moment of inertial respectively.The results show that the aerodynamic heating has little impact on the longitudinal dynamic characteristics of the hypersonic vehicle while the vehicle with free-free beam of variable cross-section moment of inertia stays more open-loop unstable at the characteristic points and the non-minimum phase behavior constraints become weaker.