Robust adaptive multiple model controller design for an airbreathing hypersonic vehicle model

Abstract

For airbreathing hypersonic flight vehicles (AHFVs), various uncertainties in addition to the coupling effects between the aerodynamics, propulsion, and structures result in a challenging control model. Capturing these uncertainties as real and complex uncertainties motivates the use of mixed-μ synthesis techniques to generate a controller. However, because the uncertainties limit achievable performance, adaptation is needed to achieve precise trajectory tracking. A new multiple model adaptive control (MMAC) approach, adaptive mixing control (AMC), is applied to achieve superior velocity and altitude tracking. The AMC approach, by combining mixed-μ synthesis and adaptive control approaches, incorporates robust-stability and -performance objectives into the control design. Discontinuous switching between candidate controllers is avoided by mixing. Stability issues of mixing multiple stabilizing controllers is addressed using a mixing strategy based on the Youla parameterization of all stabilizing controllers. An AMC scheme and a nonadaptive robust scheme (i.e. mixed-μ compensator) are designed for the uncertain AHFV model at hypersonic cruise (Mach 10, 98, 425 ft altitude). A comparison of the two approaches is conducted, and simulation results demonstrate the effectiveness of the AMC approach. © 2008 by the American Institute of Aeronautics and Astronautics, Inc.