Ioan Nascu

Bio: Ioan Nascu is an academic researcher from Technical University of Cluj-Napoca. The author has contributed to research in topics: Model predictive control & Control theory. The author has an hindex of 10, co-authored 70 publications receiving 384 citations.

A Survey of Recent Advances in Fractional Order Control for Time Delay Systems

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.

Identification and path following control of an AR.Drone quadrotor

Abstract: This paper describes the process of identification and closed-loop control of an Parrot AR.Drone Unmanned Aerial Vehicle (UAV) as well as a path following application based on IMC position controllers. The research issue is to achieve position control of the AR.Drone quadrotor movement via its on-board sensory equipment and external webcam video stream. Firstly, transfer functions are detailed for pitch and altitude movements and a comparison is made between implemented PID and IMC controller performance for both simulation and practice. Furthermore, using IMC controllers, a path following application exhibits controller behavior from a practical point of view. It is concluded that the dynamic model and the controllers implemented on the quadrotor can serve as a reliable basis for more advanced applications.

Improvements in Dissolved Oxygen Control of an Activated Sludge Wastewater Treatment Process

Abstract: Nowadays there is great emphasis on the optimization of wastewater treatment plants (WWTP) due to the strict regulations concerning discharged waters. The control techniques currently used in WWTPs include simple PLC-based proportional-integral-derivative control techniques. The most complex part of wastewater treatment is the activated sludge process, where the sewage is biologically treated by means of a microorganism culture in the presence of air or oxygen. This paper shows a simple way of decreasing the operational costs, together with an increase in performance and disturbances rejection by using fractional order Proportional-Integral controllers on the dissolved oxygen concentration and on the air pressure generated by the air blower. Closed loop system performance, using the fractional order Proportional-Integral controller, are compared to those obtained by using the conventional Proportional-Integral controller on the dissolved oxygen concentration. They prove the robustness of the former controller against the parameters variations. The controllers are designed and simulated on the mathematical model of the WWTP of Romanofir, Talmaciu.

Adaptive EPSAC predictive control of the hypnotic component in anesthesia

Abstract: The applications presented in this paper are oriented towards the study of the possibilities to apply adaptive algorithms to a model based EPSAC (Extended Prediction Self-Adaptive Control) scheme for control of depth of anesthesia (DOA). The input variable is Propofol, an anesthetic substance used for both induction and maintenance control of DOA which is evaluated by means of the Bispectral index (BIS). An adaptive control algorithm based on an indirect adaptive predictive method is used. The unknown model parameters are estimated by recursive least square algorithm. The simulation tests performed on virtually generated models for a set of 12 patients show a fast response, optimal dosage and robustness of the algorithm regarding the control of the desired BIS setpoint during induction and maintainance phase.

Model simplification of an unmanned aerial vehicle

Abstract: In this paper the authors describe the process of model simplification that can be done to an Unmanned Aerial Vehicle (UAV) in straight steady flight condition. The aim of the process is to find a simple model that can approximate as good as possible the physical model of the AR.Drone quadcopter designed by Parrot. The non-linear dynamic model of this aircraft was implemented in computational software and the results are presented at the end of the paper. This simulator can be used in future development of control techniques and strategies.

Adaptive Control

Abstract: This book, written by two major figures in adaptive control, provides a wealth of material for researchers, practitioners, and students. While some researchers in adaptive control may note the absence of a particular topic, the book‘s scope represents a high-gain instrument. It can be used by designers of control systems to enhance their work through the information on many new theoretical developments, and can be used by mathematical control theory specialists to adapt their research to practical needs. The book is strongly recommended to anyone interested in adaptive control.

On the european union

Abstract: The extent to which member states transpose EU directives in a timely fashion is often argued to be strongly associated with the general effectiveness of national bureaucracies. But what kind of institutional solutions ensure better performance? This paper examines the patterns and effects of departmental oversight across 28 ministries in Estonia, Hungary, Poland and Slovenia. In mapping the strength of oversight, it relies on around 90 structured interviews regarding the rules-in-use on transposition planning, legal review and monitoring of deadlines. The analysis of the impact of departmental oversight is based on an original dataset of over 300 directives with transposition deadlines between January 2005 and December 2008.

Modeling of the Lung Impedance Using a Fractional-Order Ladder Network With Constant Phase Elements

Abstract: The self similar branching arrangement of the airways makes the respiratory system an ideal candidate for the application of fractional calculus theory. The fractal geometry is typically characterized by a recurrent structure. This study investigates the identification of a model for the respiratory tree by means of its electrical equivalent based on intrinsic morphology. Measurements were obtained from seven volunteers, in terms of their respiratory impedance by means of its complex representation for frequencies below 5 Hz. A parametric modeling is then applied to the complex valued data points. Since at low-frequency range the inertance is negligible, each airway branch is modeled by using gamma cell resistance and capacitance, the latter having a fractional-order constant phase element (CPE), which is identified from measurements. In addition, the complex impedance is also approximated by means of a model consisting of a lumped series resistance and a lumped fractional-order capacitance. The results reveal that both models characterize the data well, whereas the averaged CPE values are supraunitary and subunitary for the ladder network and the lumped model, respectively.

A Survey of Recent Advances in Fractional Order Control for Time Delay Systems

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.

Towards Industrialization of FOPID Controllers: A Survey on Milestones of Fractional-Order Control and Pathways for Future Developments

Abstract: The interest in fractional-order (FO) control can be traced back to the late nineteenth century. The growing tendency towards using fractional-order proportional-integral-derivative (FOPID) control has been fueled mainly by the fact that these controllers have additional “tuning knobs” that allow coherent adjustment of the dynamics of control systems. For instance, in certain cases, the capacity for additional frequency response shaping gives rise to the generation of control laws that lead to superior performance of control loops. These fractional-order control laws may allow fulfilling intricate control performance requirements that are otherwise not in the span of conventional integer-order control systems. However, there are underpinning points that are rarely addressed in the literature: (1) What are the particular advantages (in concrete figures) of FOPID controllers versus conventional, integer-order (IO) PID controllers in light of the complexities arising in the implementation of the former? (2) For real-time implementation of FOPID controllers, approximations are used that are indeed equivalent to high-order linear controllers. What, then, is the benefit of using FOPID controllers? Finally, (3) What advantages are to be had from having a near-ideal fractional-order behavior in control practice? In the present paper, we attempt to address these issues by reviewing a large portion of relevant publications in the fast-growing FO control literature, outline the milestones and drawbacks, and present future perspectives for industrialization of fractional-order control. Furthermore, we comment on FOPID controller tuning methods from the perspective of seeking globally optimal tuning parameter sets and how this approach can benefit designers of industrial FOPID control. We also review some CACSD (computer-aided control system design) software toolboxes used for the design and implementation of FOPID controllers. Finally, we draw conclusions and formulate suggestions for future research.