Open AccessComprehensive design of uniform robust exact disturbance observer and fixed‐time controller for reusable launch vehicles
Author(s) -
You Ming,
Zong Qun,
Tian Bailing,
Zhao Xinyi,
Zeng Fanlin
Publication year - 2018
Publication title -
iet control theory and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.059
H-Index - 108
eISSN - 1751-8652
pISSN - 1751-8644
DOI - 10.1049/iet-cta.2017.0466
Subject(s) - control theory (sociology) , convergence (economics) , controller (irrigation) , observer (physics) , computer science , disturbance (geology) , stability (learning theory) , fixed point , robust control , control engineering , control system , mathematics , control (management) , engineering , paleontology , physics , electrical engineering , quantum mechanics , artificial intelligence , agronomy , biology , mathematical analysis , machine learning , economics , economic growth
The comprehensive design of uniform robust exact disturbance observer (UREDO) and fixed‐time controller for reusable launch vehicles is investigated. A UREDO which can estimate the disturbance after a fixed‐time independent of the initial error is presented. Based on the disturbance estimation, a non‐singular terminal sliding mode controller is designed to ensure that the guidance command can be tracked within a fixed‐time in the presence of model uncertainties and external disturbances. A proof of the fixed‐time convergence of the closed‐loop system under the control scheme is derived with complete stability analysis using the Lyapunov technique. The features of the proposed control scheme contain that the disturbance estimation, as well as the attitude tracking, can be achieved within a fixed‐time, which is independent of initial conditions and the derivative information of states is not essential, which is valuable in engineering application. Numerical simulations are performed to demonstrate the fixed‐time convergence performance of the proposed control scheme.