Control-relevant modeling and performance limitation analysis for flexible air-breathing hypersonic vehicles

Abstract

Overall design in many air-breathing hypersonic vehicles (AHSVs) uses the integrated airframe/scramjet configuration formed with elongated fuselage and light structure, resulting in intricate aerodynamic–propulsive-elastic couplings. In this paper, a high-fidelity flexible AHSV dynamic modeling procedure is proposed at first, which consists of three main parts: i) panel method based aerodynamic modeling; ii) scramjet modeling; iii) finite-element-method (FEM) based aeroelastic modeling. Unsteady and viscous effects are estimated through linear piston theory and Eckert's reference temperature method, respectively. Additional models for shock interaction, ram-to-scram transition, and finite rate chemistry reaction are also included. To overcome the intractability of physics-based model, the Morris method is applied to identify the main influence factors during surrogate modeling. Then to investigate the flexible mode effect on the stability boundary, the principle of Null-controllability region (NCR) is employed, under control input saturation and bandwidth constraints.The X-43A like air-breathing hypersonic vehicle operating at cruise condition is studied for verification purpose, and the Monte-Carlo simulation results demonstrate the effectiveness of the proposed dynamic modeling and performance limitation analysis approach.