Premium
Discrete‐time design and applications of uncertainty and disturbance estimator
Author(s) -
Padmanabhan Ram,
Shetty Maithili,
Chandar T. S.
Publication year - 2021
Publication title -
international journal of robust and nonlinear control
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.361
H-Index - 106
eISSN - 1099-1239
pISSN - 1049-8923
DOI - 10.1002/rnc.5518
Subject(s) - discrete time and continuous time , control theory (sociology) , estimator , nonlinear system , computer science , sampling (signal processing) , filter (signal processing) , control engineering , law , control (management) , engineering , mathematics , artificial intelligence , statistics , physics , quantum mechanics , political science , computer vision
This article proposes a discrete‐time design for the robust control technique of uncertainty and disturbance estimator (UDE), with studies on applications to real‐world systems. Despite the ease of implementation of discrete‐time strategies, almost all prior work on UDE is for designing continuous‐time control laws, with no general, complete research for discrete‐time design. To design an appropriate discrete‐time control law, a novel digital filter similar to the original analog filter for disturbance estimation is designed, a discrete‐time error‐based control law is derived, and a detailed stability analysis is provided. However, most real‐world, physical systems are nonlinear and continuous‐time in nature. Thus, the techniques of sampling and digital‐analog (D/A) conversion are used, enabling the control of linear, time‐invariant as well as a class of nonlinear, continuous‐time systems using discrete‐time UDE. The considered nonlinear system is for the phenomenon of wing‐rock motion. Simulations are performed for the proposed techniques, and results indicate highly accurate stabilization and tracking performance, with excellent disturbance rejection. In particular, it is seen that the proposed control law is less sensitive to initial values of the error when compared to the original continuous‐time UDE law.