Article
Automation & Control Systems
Matheus S. de Oliveira, Kayol S. Mayer, Renan L. Pereira
Summary: This paper presents novel discrete-time H-2 and H-infinity filter designs for polytopic LPV systems. The proposed conditions recover the established polyquadratic concept and allow for improved filters. Numerical examples demonstrate the feasibility and performance of the proposed design methods.
INTERNATIONAL JOURNAL OF SYSTEMS SCIENCE
(2022)
Article
Automation & Control Systems
Renan L. Pereira, Matheus S. de Oliveira, Karl H. Kienitz
Summary: This paper introduces a new H2 state-feedback control synthesis for discrete-time polytopic LPV systems, using a less conservative approach compared to existing literature. The proposed method is capable of handling systems with time-varying parameters and providing an improved condition for quadratic H2 control synthesis.
OPTIMAL CONTROL APPLICATIONS & METHODS
(2021)
Article
Automation & Control Systems
Cheng Hu, Imad M. Jaimoukha
Summary: This article introduces new linear matrix inequality sufficient conditions for a generalized robust state feedback control synthesis problem, providing more accurate results compared to existing methods. It also proposes an iterative algorithm and an alternative method for systems with difficult initial solution finding.
INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL
(2021)
Article
Computer Science, Artificial Intelligence
Jason J. R. Liu, Ka-Wai Kwok, James Lam
Summary: In this paper, we study the decentralized H2 state-feedback control problem for networked discrete-time systems with positivity constraint. We propose necessary and sufficient synthesis conditions for networked positive systems, unlike most previous works that only provide sufficient conditions for a single positive system. We develop a primal-dual iterative algorithm based on these conditions to solve the problem and avoid converging to a local minimum. Two illustrative examples are used to verify our proposed results.
IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS
(2023)
Article
Computer Science, Information Systems
Leonardo de Paula Carvalho, Jonathan M. Palma, Tabitha E. Rosa, Bayu Jayawardhana, Oswaldo Luiz Do Valle Costa
Summary: This study investigates a fault detection problem using a gain-scheduled filter for discrete-time Linear Parameter Varying systems. Three design approaches are proposed and numerical simulations are provided to illustrate the applicability and performance of the proposed methods.
Article
Computer Science, Artificial Intelligence
Adolfo Perrusquia, Wen Yu
Summary: This article discusses the H-2 control approach for unknown nonlinear systems in discrete time using a discrete-time recurrent neural network to model the system and applying H-2 tracking control based on the neural model. To improve tracking accuracy and robustness, reinforcement learning and another neural approximator are utilized. The stability of the neural identifier and the H-2 tracking control are proven, and the convergence of the approach is demonstrated through control of pan and tilt robots and surge tanks.
IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS
(2021)
Article
Mathematics
Lin Chen, Shusheng Bi, Jun Cheng, Yueri Cai, Fanghua Mei
Summary: This paper investigates the H-infinity and H-2 time-varying formation tracking problems for multi-agent systems with directed topologies in the presence of external disturbances. A distributed consensus protocol based on the local state information is proposed to solve the tracking problems without utilizing global information. Algorithms for determining suitable parameters of the protocol are presented. The closed-loop stability of the system in the presence of external disturbances is demonstrated using algebraic graph theory and Lyapunov analysis.
Article
Automation & Control Systems
Yangzhou Chen, Xiaolong Huang, Jingyuan Zhan
Summary: This study focuses on gain-scheduled robust control for multi-agent LPV systems, transforming the robust consensus control problem into a robust stability problem through a linear transformation matrix, and deriving consensus conditions using LMIs. Control gain matrices are obtained through solving a convex optimization problem.
INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL
(2022)
Article
Automation & Control Systems
Amanda Spagolla, Cecilia F. Morais, Ricardo C. L. F. Oliveira, Pedro L. D. Peres
Summary: This article investigates the problem of designing robust static output-feedback or state-feedback controllers for discrete-time positive linear systems affected by time-invariant or time-varying parameters belonging to a polytope. It proposes an iterative procedure based on robust linear matrix inequalities to directly handle the control gain as an optimization variable. The method is shown to be less conservative than other approaches, providing solutions for cases where traditional design techniques cannot be applied.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2022)
Article
Automation & Control Systems
Ali Abdullah, Nirvana Borham
Summary: This paper investigates the problem of designing mixed H2/H infinity model reference control (MRC) systems for linear parameter-varying discrete-time systems. Two types of mixed H2/H infinity MRC systems, namely the state-feedback and dynamic output-feedback MRC systems, are considered and designed using a parameter-dependent Lyapunov function. The experimental results of the aeropendulum system are used to evaluate the proposed controllers and demonstrate their effectiveness in achieving satisfactory performances of the closed-loop systems.
INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL
(2022)
Article
Automation & Control Systems
Reza Yavari, Saeed Shamaghdari, Arash Sadeghzadeh
Summary: This paper addresses the problem of Robust Switching Gain-Scheduled Output-Feedback (RSGSOF) H-2 controller synthesis for polytopic uncertain continuous-time linear parameter varying (LPV) systems. The proposed robust switching gain-scheduled control design scheme overcomes the limitations of existing methods and investigates the design problem of H-2 output-feedback Bumpless Transfer Controller (BTC). The proposed BTC combines multiple LPV controllers with the objective of limiting control bumps and utilizes a Lyapunov-based min-switching rule for switching between these controllers.
EUROPEAN JOURNAL OF CONTROL
(2022)
Article
Automation & Control Systems
Bin Zhou, Kang-Kang Zhang, Huaiyuan Jiang
Summary: This paper studies the prescribed-time control problem of nonholonomic systems. By using properties of parametric Lyapunov equations and constructing time-varying Lyapunovlike functions, a time-varying high-gain feedback controller is proposed for the nonholonomic system to achieve convergence to zero at any prescribed time. The advantage of time-varying feedback is shown through comparison with time-invariant feedback. Time-varying high-gain feedback controllers for perturbed nonholonomic systems are also designed, considering both state feedback and observer based output feedback, and their boundedness is proved in all cases. Numerical examples are presented to verify the effectiveness of the proposed methods.
Article
Automation & Control Systems
Jian Liu, Yuanshi Zheng, YangQuan Chen
Summary: This note discusses the problem of designing a time-varying learning gain to achieve the monotone convergence of system output tracking errors (SOTEs) in iterative learning control systems. It first points out that the iterative learning control update law with exponentially decaying learning factor cannot guarantee the monotonic convergence of SOTEs in terms of 1-norm, 2-norm, or co-norm. It then proves that there exists a time-varying learning gain to achieve the monotone convergence of SOTEs in terms of the unweighted co-norm, but there is no time-varying learning gain to ensure monotone convergence in terms of unweighted 1-norm. Finally, a sufficient condition is presented for the existence of a time-varying learning gain to ensure monotone convergence of SOTEs in terms of unweighted 2-norm.
Article
Automation & Control Systems
Gabriela L. Reis, Rodrigo F. Araujo, Leonardo A. B. Torres, Reinaldo M. Palhares
Summary: This paper introduces a novel approach to design parameter-dependent state feedback controllers to address the local stabilization problem of nonlinear systems. The proposed method is validated through numerical examples, showing favorable comparisons with recently published similar approaches.
INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL
(2021)
Article
Automation & Control Systems
Jonathan M. Palma, Cecilia F. Morais, Ricardo C. L. F. Oliveira
Summary: This article proposes a novel method for designing static output-feedback controllers for linear parameter-varying discrete-time systems by enriching the system dynamics. Unlike previous methods, it introduces a locally convergent iterative procedure based on linear matrix inequalities. The approach treats control gains as optimization variables, handles state- and output-feedback similarly, and addresses constraints without introducing additional conservativeness.
INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL
(2021)
Article
Automation & Control Systems
Lucas C. Borin, Caio R. D. Osorio, Gustavo G. Koch, Ricardo C. L. F. Oliveira, Vinicius F. Montagner
Summary: This paper presents a new design procedure for robust state feedback current controllers for grid-tied inverters under wide grid impedance ranges. The procedure combines particle swarm optimization and linear matrix inequalities. The proposed procedure minimizes an objective function to obtain control gains and ensures the closed-loop system's robust stability. Real-time simulations and experimental results confirm the stability and optimized performance of the closed-loop system.
CONTROL ENGINEERING PRACTICE
(2022)
Article
Automation & Control Systems
Amanda Spagolla, Cecilia F. Morais, Ricardo C. L. F. Oliveira, Pedro L. D. Peres
Summary: This article investigates the problem of designing robust static output-feedback or state-feedback controllers for discrete-time positive linear systems affected by time-invariant or time-varying parameters belonging to a polytope. It proposes an iterative procedure based on robust linear matrix inequalities to directly handle the control gain as an optimization variable. The method is shown to be less conservative than other approaches, providing solutions for cases where traditional design techniques cannot be applied.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2022)
Article
Automation & Control Systems
Ariadne L. J. Bertolin, Ricardo C. L. F. Oliveira, Giorgio Valmorbida, Pedro L. D. Peres
Summary: This article addresses the problem of static output-feedback control design for uncertain discrete-time Lur'e systems with bounded nonlinearities, proposing new synthesis conditions based on linear matrix inequalities and an iterative algorithm to search for stabilizing gains. The approach can handle different types of constraints without introducing additional conservatism.
INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL
(2022)
Article
Automation & Control Systems
Amanda Spagolla, Alvaro A. Lemaire, Cecilia F. Morais, Ricardo C. L. F. Oliveira, Pedro L. D. Peres
Summary: This paper addresses the problems of H-2 and H-∞ control design for positive continuous-time linear systems with uncertain parameters. It proposes a method based on linear matrix inequalities to obtain stabilizing gain and H-2 (or H-∞) guaranteed cost. The method allows for independent optimization of the gain and the Lyapunov matrix, and does not require a diagonal structure on the matrix used to enforce closed-loop positivity.
JOURNAL OF THE FRANKLIN INSTITUTE-ENGINEERING AND APPLIED MATHEMATICS
(2022)
Article
Engineering, Multidisciplinary
Everson Mattos, Lucas Cielo Borin, Caio Ruviaro Dantas Osorio, Gustavo G. Koch, Ricardo C. L. F. Oliveira, Vinicius Foletto Montagner
Summary: This paper proposes an offline automated control design procedure to obtain multiple robust optimized proportional-resonant controllers for grid-connected converters with LCL filters operating under uncertain grid conditions. The proposed procedure includes two steps, using a particle swarm algorithm to obtain the optimal active damping gains for LCL filter resonance and minimizing the tracking error index for multiple proportional-resonant controllers. The robust stability of the closed-loop system with the metaheuristics-tuned control gains is certified through a parameter-dependent Lyapunov function.
IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS
(2023)
Article
Energy & Fuels
Gustavo G. Koch, Caio R. D. Osorio, Ricardo C. L. F. Oliveira, Vinicius F. Montagner
Summary: This paper presents a procedure to design robust controllers for three-phase inverters with LCL filters connected to a grid with uncertain and possibly time-varying impedances. The proposed design procedure allows the implementation of robust state feedback controllers with a reduced number of sensors and provides larger regions of guaranteed stability compared with similar conditions in the literature. The control law using observed states ensures grid currents with low harmonic content and satisfies the IEEE 1547 Standard requirements. Experimental results confirm the viability of the proposed design.
Article
Automation & Control Systems
Raul T. Bernardo, Luciola Campestrini, Ricardo C. L. F. Oliveira, Antonio F. C. Aquino, Daniel Dotta
Summary: This research proposes a data-driven control design method based on remote input signals for designing oscillation damping controllers in order to address the challenges posed by complex interconnected power systems and intermittent renewable sources. The use of remote signals in a wide-area damping controller (WADC) approach leads to efficient inter-area damping control. The method has fast-solving characteristics and can re-establish damping performance after a change in operating condition in an online implementation.
JOURNAL OF CONTROL AUTOMATION AND ELECTRICAL SYSTEMS
(2023)
Proceedings Paper
Automation & Control Systems
Paulo J. de Oliveira, Ricardo C. L. F. Oliveira, Pedro L. D. Peres
Summary: This article investigates the robust stability of uncertain continuous-time linear systems with interval parameters and proposes an iterative algorithm based on LMIs. The method treats interval bounds as optimization variables and can be used to search for the maximum variation around nominal values.
Article
Mathematics
Roberto M. Fuentes, Jonathan M. Palma, Hildo Guillardi Junior, Marcio J. Lacerda, Leonardo de P. Carvalho, Alejandro J. Rojas, Ricardo C. L. F. Oliveira
Summary: This paper investigates control design for dc-dc converters, proposing a method based on Linear Parameter-Varying (LPV) models to compute robust gains and solve the issues of input voltage variations and constant power load.
Article
Automation & Control Systems
Amanda Spagolla, Cecilia F. Morais, Ricardo C. L. F. Oliveira, Pedro L. D. Peres
Summary: This letter investigates the problems of reduced order H-2 and H-infinity positive filter design for positive uncertain discrete-time linear systems. It proposes new LMI conditions which treat the filter matrices as variables, solving the issue of not being able to obtain optimal filters through standard LMI methods under the positivity constraint.
IEEE CONTROL SYSTEMS LETTERS
(2022)
Article
Automation & Control Systems
Ariadne L. J. Bertolin, Ricardo C. L. F. Oliveira, Giorgio Valmorbida, Pedro L. D. Peres
Summary: This letter investigates the problem of stability analysis and output-feedback stabilization of discrete-time Lur'e systems with odd and slope bounded nonlinearities. An iterative algorithm based on LMIs is constructed to assess stability and output-feedback stabilization using the existence of a Zames-Falb multiplier of any given order based on independent positive definite matrices. Numerical examples validate the performance of the proposed approach.
IEEE CONTROL SYSTEMS LETTERS
(2022)
Article
Automation & Control Systems
Andressa M. Souza, Ricardo C. L. F. Oliveira, Pedro L. D. Peres
Summary: This letter presents a method for model match control of uncertain continuous-time linear systems using fixed order dynamic output-feedback. The H-infinity norm is used as a performance metric and the synthesis conditions are formulated as LMIs solved iteratively. The novel aspect of this approach is that both the controller matrices and the reference model matrices appear affinely in the conditions, allowing for structured controllers and providing additional degrees of freedom for the reference model.
IEEE CONTROL SYSTEMS LETTERS
(2022)