2017
Autores
Junior, FS; Oliveira, J; Araújo, A;
Publicação
International Journal of Innovative Computing, Information and Control
Abstract
This paper presents the design of a robust pole placement controller for linear and time invariant systems described by models whose parameters are unknown but, with known bounds, using only plant, input, and output signals. The main objective is to locate the closed-loop poles within a region specified by an interval characteristic polynomial, chosen based on performance specifications and whose stability is guaranteed by Kharitonov’s theorem. The procedure to find a closed interval for each controller parameter is formulated us a nonlinear programming (NLP) problem and switching laws based on the variable structure adaptive pole placement control (VS-APPC) are used to estimate the unknown plant, parameters. This innovative strategy gives a fast, and non-oscillatory transient,, smooth control signal and robustness to large model parameter variations. Moreover, the constraints imposed by the interval controller meet the closed-loop performance requirements. Simulation results are presented for second order nonminimum phase plants, to illustrate the properties of the proposed technique. © 2017 ICIC International.
2013
Autores
Teixeira, L; Oliveira, J; Araujo, A;
Publicação
2013 EUROPEAN CONTROL CONFERENCE (ECC)
Abstract
In this paper it is proposed an indirect approach to the Dual Mode Adaptive Robust Controller (DMARC), which combines the typical transient and robustness properties of Variable Structure Systems, with a smooth control signal in steady-state, typical of conventional Adaptive Controllers, as Model Reference Adaptive Controller (MRAC). The aim of this indirect version, here named Indirect Dual Mode Adaptive Robust Controller (IDMARC), is to provide a more intuitive controller design, based on physical plant parameters, as resistances, inertia moments, capacitances, etc maintaining DMARC properties. In this paper, it will be presented a stability analysis for the proposed controller and simulations to an unstable second order plant.
2015
Autores
Teixeira, LRL; Oliveira, JB; Araujo, AD;
Publicação
INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL
Abstract
In this paper, an indirect approach to the dual-mode adaptive robust controller (DMARC) is proposed, which combines the typical transient and robustness properties of variable structure systems with a smooth control signal in steady state, typical of conventional adaptive controllers, as model reference adaptive controller. The aim of this indirect version, here named indirect DMARC, is to provide a more intuitive controller design, based on physical plant parameters, as resistances, inertia moments, capacitances, and so on, maintaining DMARC properties. In this paper, a stability analysis for the proposed controller and simulations to an unstable second-order plant will be presented. Copyright (c) 2013 John Wiley & Sons, Ltd.
2013
Autores
Oliveira, JB;
Publicação
IFAC Proceedings Volumes
Abstract
2015
Autores
Teixeira, LRL; Oliveira, JB; Araujo, AD;
Publicação
Journal of Control, Automation and Electrical Systems
Abstract
2018
Autores
Oliveira, J; Oliveira, PM; Pinho, TM; Cunha, JB;
Publicação
IFAC PAPERSONLINE
Abstract
Half-cycle Posicast Control is currently used in a vast range of applications. Although the proved benefits of this technique, one of its major disadvantages concerns model uncertainties. This has motivated the development and integration of robust methods to overcome this issue. In this paper, a practical experiment for auto-tuning of a two degrees of freedom control configuration using a Half-Cycle Posicast pre-filter (or input-shaping), and a PID controller under parametric variations is presented. The proposed method requires using an oscillatory system model in an auto-tuning control structure. The error derivative among the model and system output is used to trigger both the identification and retuning procedure. The proposed method is flexible for choosing identification plus optimization methods. Practical results obtained for electronic filter plants suggest improved performance for the considered cases. © 2018
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