Adaptive parameter estimation control of nonminimum phase hypersonic flight vehicle

Abstract

In this study, considering the longitudinal dynamic model of a nonminimum phase hypersonic flight vehicle, output-redefinition-based adaptive parameter estimation control is proposed. Output redefinition is employed to transform unstable internal dynamics to asymptotically stable internal dynamics. Based on the coordinate transformation of the redefined internal dynamics, the pitch angle command is derived and used as the reference command of the input-output subsystem. For the redefined attitude subsystem and the velocity subsystem, the unknown aerodynamic functions are decomposed into the known state vector and the unknown aerodynamic parameter vector, that is the linear parametric form. The adaptive updating laws are constructed to estimate the aerodynamic parameter vectors, and then the dynamic inversion control is designed for the velocity subsystem and the backstepping control is designed for the input-output subsystem. The system stability is analyzed via the Lyapunov stability theorem while simulation studies are conducted to illustrate the effectiveness of the proposed method.