Nonlinear optimal control for autonomous hypersonic vehicles

Abstract

The article proposes a nonlinear optimal (H-infinity) control method for a hypersonic aerial vehicle (HSV). The dynamic model of the hypersonic vehicle undergoes approximate linearization around a temporary operating point which is recomputed at each iteration of the control method. This operating point consists of the present value of the system's state vector and of the last value of the control inputs vector that was applied on the HSV. The linearization relies on Taylor series expansion and on the computation of the associated Jacobian matrices. For the approximately linearized model of the hypersonic aerial vehicle, an optimal (H-infinity) feedback controller was designed. To compute the controller's feedback gains, an algebraic Riccati equation had to be repetitively solved at each iteration of the control algorithm. The global asymptotic stability of the control method is proven through Lyapunov analysis. The control scheme remains robust against model uncertainties an external perturbations.

Attitude dynamic tracking control of an agile satellite using a fixed-structured H∞ synthesis method

“…According to Eq. (22), substituting the transfer functions of the actuator (11) and the rigid part of the satellite (5) gives the feedforward compensator:…”

“…In Ref. [5], a nonlinear optimal H ∞ control method is proposed for a hypersonic aerial vehicle and algebraic Riccati equations are solved to compute the controller's feedback gains. The method is proved to be robust against model uncertainty.…”