Observer-based robust control for a flexible launch vehicle

Abstract

This article investigates the problem of robust stabilization for a flexible launch vehicle. Since the launch vehicle suffers from parametric uncertainties, bending modes, and external wind disturbances simultaneously, an observer-based methodology is provided to address these negative factors. The proposed method can guarantee the stability of the closed-loop system and minimize the H∞ performance index. Additional regional pole placement constraints are imposed on the feedback gain matrices to improve the transient performance of the system. A two-step strategy is proposed to solve the involving bilinear matrix inequality problem. Compared with existing methods, which mainly depend on introducing additional constraints to linearize the bilinear matrix inequality conditions, the proposed strategy can reduce the conservatism and is suitable for engineering practice. The simulation results for one operating point and nonlinear model illustrate the validity and effectiveness of the proposed control method.

Attenuation of the effects produced by the bending modes of a flexible launch vehicle using second order filters

“…A ʆ1 adaptive output feedback controller is proposed in [9], being able to handle unstable flexible plant with large parametric variation. Another method is used in [10] consisting of an observer-based methodology capable to robustly stabilizing a flexible launch vehicle.…”

A new robust observer design for nonlinear systems with application to fault diagnosis

“…Over the last decades, different types of estimator have been developed for both linear and nonlinear systems (Jiang et al, 2015; Li et al, 2016; Ou et al, 2015; Qi and Hu, 2017; Wu and Duan, 2007). The design of observers for nonlinear systems has been generalized by Besançon and Hammouri (1996).…”