scholarly journals Relaxed formulation of the design conditions for Takagi-Sugeno fuzzy virtual actuators

2016 ◽  
Vol 26 (2) ◽  
pp. 199-221 ◽  
Author(s):  
Anna Filasová ◽  
Dušan Krokavec ◽  
Pavol Liščinský

Abstract The H∞ norm approach to virtual actuators design, intended to Takagi-Sugeno fuzzy continuous-time systems, is presented in the paper. Using the second Ljapunov method, the design conditions are formulated in terms of linear matrix inequalities in adapted bounded real lemma structures. Related to the static output controller, and for systems under influence of single actuator faults, the design steps are revealed for a three-tank system plant.

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Kamel Dabboussi ◽  
Jalel Zrida

New sufficient dilated linear matrix inequality (LMI) conditions for the static output feedback control problem of linear continuous-time systems with no uncertainty are proposed. The used technique easily and successfully extends to systems with polytopic uncertainties, by means of parameter-dependent Lyapunov functions (PDLFs). In order to reduce the conservatism existing in early standard LMI methods, auxiliary slack variables with even more relaxed structure are employed. It is shown that these slack variables provide additional flexibility to the solution. It is also shown, in this paper, that the proposed dilated LMI-based conditions always encompass the standard LMI-based ones. Numerical examples are given to illustrate the merits of the proposed method.


Author(s):  
Yin-Lam Chow ◽  
Yue-Bing Hu ◽  
Xianwei Li ◽  
Andreas Kominek ◽  
James Lam

In this paper, the problem of mixed additive/multiplicative model reduction for stable linear continuous-time systems is studied. To deal with nonsquare or nonminimum phase systems, the multiplicative error bound is constructed using spectral factorization technique. By virtue of the bounded real lemma and the projection lemma, a linear matrix inequality approach is proposed for mixed additive/multiplicative H∞ model reduction, which can be implemented by the well-known cone complementary linearization method. Finally, two numerical examples are provided to demonstrate the effectiveness and advantages of the obtained results.


Author(s):  
H. Ghorbel ◽  
A. El Hajjaji ◽  
M. Souissi ◽  
M. Chaabane

In this paper, a robust fuzzy observer-based tracking controller for continuous-time nonlinear systems presented by Takagi–Sugeno (TS) models with unmeasurable premise variables, is synthesized. Using the H∞ norm and Lyapunov approach, the control design for TS fuzzy systems with both unmeasurable premises and system states is developed to guarantee tracking performance of closed loop systems. Sufficient relaxed conditions for synthesis of the fuzzy observer and the fuzzy control are driven in terms of linear matrix inequalities (LMIs) constraints. The proposed method allows simplifying the design procedure and gives the observer and controller gains in only one step. Numerical simulation on a two tank system is provided to illustrate the tracking control design procedure and to confirm the efficiency of the proposed method.


2020 ◽  
Vol 42 (12) ◽  
pp. 2308-2323
Author(s):  
Salama Makni ◽  
Maha Bouattour ◽  
Ahmed El Hajjaji ◽  
Mohamed Chaabane

In this work, we investigate the problem of control for nonlinear systems represented by Takagi-Sugeno (T-S) fuzzy models affected by both sensor and actuator faults subject to an unknown bounded disturbances (UBD). For this, we design an adaptive observer to estimate state, sensor and actuator fault vectors simultaneously despite the presence of external disturbances. Based on this observer, we develop a fault tolerant control (FTC) law not only to stabilize closed loop system, but also to compensate the fault effects. For the observer-based controller design, we propose less conservative conditions formulated in terms of linear matrix inequalities (LMIs). Moreover, both observer and controller gains are calculated via solving a set of LMIs only in single step. Finally, comparative results and an application to single-link flexible joint robot are afforded to prove the efficiency of the proposed design.


2013 ◽  
Vol 23 (2) ◽  
pp. 169-186 ◽  
Author(s):  
Anna Filasová ◽  
Daniel Gontkovič ◽  
Dušan Krokavec

The paper is engaged with the framework of designing adaptive fault estimation for linear continuous-time systems with distributed time delay. The Lyapunov-Krasovskii functional principle is enforced by imposing the integral partitioning method and a new equivalent delaydependent design condition for observer-based assessment of faults are established in terms of linear matrix inequalities. Asymptotic stability conditions are derived and regarded with respect to the incidence of structured matrix variables in the linear matrix inequality formulation. Simulation results illustrate the design approach, and demonstrates power and performance of the actuator fault assessment.


2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Qing Wang ◽  
Maopeng Ran ◽  
Chaoyang Dong ◽  
Maolin Ni

We present an improved antiwindup design for linear invariant continuous-time systems with actuator saturation nonlinearities. In the improved approach, two antiwindup compensators are simultaneously designed: one activated immediately at the occurrence of actuator saturation and the other activated in anticipatory of actuator saturation. Both the static and dynamic antiwindup compensators are considered. Sufficient conditions for global stability and minimizing the inducedL2gain are established, in terms of linear matrix inequalities (LMIs). We also show that the feasibility of the improved antiwindup is similar to the traditional antiwindup. Benefits of the proposed approach over the traditional antiwindup and a recent innovative antiwindup are illustrated with well-known examples.


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