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Author

Cristina I. Muresan

Other affiliations: Core Laboratories
Bio: Cristina I. Muresan is an academic researcher from Technical University of Cluj-Napoca. The author has contributed to research in topics: PID controller & Control theory. The author has an hindex of 14, co-authored 122 publications receiving 1046 citations. Previous affiliations of Cristina I. Muresan include Core Laboratories.

Papers published on a yearly basis

Papers
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Journal ArticleDOI
TL;DR: A novel approach for the auto-tuning of fractional order controllers is proposed, based on a simple experiment that is able to determine the modulus, phase and phase slope of the process required in the computation of the controller parameters.
Abstract: Fractional order PID controllers benefit from an increasing amount of interest from the research community due to their proven advantages. The classical tuning approach for these controllers is based on specifying a certain gain crossover frequency, a phase margin and a robustness to gain variations. To tune the fractional order controllers, the modulus, phase and phase slope of the process at the imposed gain crossover frequency are required. Usually these values are obtained from a mathematical model of the process, e.g. a transfer function. In the absence of such model, an auto-tuning method that is able to estimate these values is a valuable alternative. Auto-tuning methods are among the least discussed design methods for fractional order PID controllers. This paper proposes a novel approach for the auto-tuning of fractional order controllers. The method is based on a simple experiment that is able to determine the modulus, phase and phase slope of the process required in the computation of the controller parameters. The proposed design technique is simple and efficient in ensuring the robustness of the closed loop system. Several simulation examples are presented, including the control of processes exhibiting integer and fractional order dynamics.

122 citations

Journal ArticleDOI
TL;DR: This paper proposes a simple approach for designing a fractional order PI controller for controlling the speed of a DC motor, implemented on an FPGA target and its performance is compared to other possible benchmarks.

98 citations

Journal ArticleDOI
TL;DR: The purpose of this paper is to provide a state of the art that can be easily used as a basis to familiarize oneself with fractional order tuning strategies targeted for time delayed processes.
Abstract: Several papers reviewing fractional order calculus in control applications have been published recently. These papers focus on general tuning procedures, especially for the fractional order proportional integral derivative controller. However, not all these tuning procedures are applicable to all kinds of processes, such as the delicate time delay systems. This motivates the need for synthesizing fractional order control applications, problems, and advances completely dedicated to time delay processes. The purpose of this paper is to provide a state of the art that can be easily used as a basis to familiarize oneself with fractional order tuning strategies targeted for time delayed processes. Solely, the most recent advances, dating from the last decade, are included in this review.

89 citations

Journal ArticleDOI
TL;DR: Two tuning algorithms for fractional-order internal model control (IMC) controllers for time delay processes based on two specific closed-loop control configurations, based on the IMC control structure and the Smith predictor structure are presented.
Abstract: This paper presents two tuning algorithms for fractional-order internal model control (IMC) controllers for time delay processes. The two tuning algorithms are based on two specific closed-loop control configurations: the IMC control structure and the Smith predictor structure. In the latter, the equivalency between IMC and Smith predictor control structures is used to tune a fractional-order IMC controller as the primary controller of the Smith predictor structure. Fractional-order IMC controllers are designed in both cases in order to enhance the closed-loop performance and robustness of classical integer order IMC controllers. The tuning procedures are exemplified for both single-input-single-output as well as multivariable processes, described by first-order and second-order transfer functions with time delays. Different numerical examples are provided, including a general multivariable time delay process. Integer order IMC controllers are designed in each case, as well as fractional-order IMC...

70 citations

Journal ArticleDOI
TL;DR: In this article, the authors proposed a methodology for designing and tuning fractional order controllers for a class of unstable second-order processes, by means of Riemann surfaces and a proper mapping in the plane.
Abstract: Although a considerable amount of research has been carried out in the field of fractional order controllers, the majority of the results deal with stable processes. Very little research has been reported regarding the design, analysis, and tuning of fractional order controllers for unstable processes. This paper proposes a methodology for designing and tuning fractional order controllers for a class of unstable second-order processes. The design is carried out using the stability analysis of fractional order systems, by means of Riemann surfaces and a proper mapping in the $$w{\text {-}}\hbox {plane}$$ . The resulting fractional order controllers are implemented using graphical programming on industrial equipment and are validated experimentally using a laboratory scale magnetic levitation unit.

62 citations


Cited by
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[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Book ChapterDOI
01 Jan 2015

3,828 citations

Journal ArticleDOI
TL;DR: This review investigates its progress since the first reported use of control systems, covering the fractional PID proposed by Podlubny in 1994, and is presenting a state-of-the-art fractionalpid controller, incorporating the latest contributions in this field.

447 citations

01 Jan 2016
TL;DR: Formulas for natural frequency and mode shape is available in the authors' book collection an online access to it is set as public so you can get it instantly.
Abstract: formulas for natural frequency and mode shape is available in our book collection an online access to it is set as public so you can get it instantly. Our book servers hosts in multiple countries, allowing you to get the most less latency time to download any of our books like this one. Kindly say, the formulas for natural frequency and mode shape is universally compatible with any devices to read.

333 citations

Journal ArticleDOI
TL;DR: An aggregate model of EV fleets and improved version of fractional order (FO) controller is provided in all the areas for robust LFC considering bilateral transactions and Numerous simulations are conducted to validate the superiority of the proposed control strategy.
Abstract: Introduction of vehicle-to-grid technology offer electric vehicles (EVs) to participate in different ancillary services under competitive electric market. EVs provide an opportunity to grow new products and services for grid management. Particularly, EVs, which is a new form of distributed energy storage, can be used to compensate the uncontracted power in the local area if the contracts between the market players are violated. This paper presents the participation of EVs for load frequency control (LFC) under deregulated environment along with other conventional sources such as hydro, thermal, and gas turbine units. An aggregate model of EV fleets and improved version of fractional order (FO) controller is provided in all the areas for robust LFC considering bilateral transactions. Flower pollination algorithm, which is one of the new proven nature inspired algorithm employed to choose the optimal parameters of the FO controllers under several scenarios. Numerous simulations are conducted to validate the superiority of the proposed control strategy.

199 citations