2023 |
Ounis, Walid; Chetoui, Manel; Najar, Salheddine; Aoun, Mohamed Programmable analogue fractional controller realization Conférence 2023. Résumé | Liens | BibTeX | Étiquettes: Analog circuits, Continuous time systems, Controllers, Digital potentiometer, First order, First order low-pass filter, Fractional integrators, Fractional-order controllers, Higher order dynamics systems, Low pass filters, Low-pass filters, Operational amplifiers, Potentiometers (electric measuring instruments), Programmable analog circuit, Programmable analogs, Real- time, Signal processing, Timing circuits @conference{Ounis2023b,A fractional-order controller is an infinite-memory system. It is described by a continuous time irrational transfer function. Its realization is a delicate problem especially when its parameters are real time tunable. This paper presents a real-time programmable analogue fractional controller implementation. The controller is based on a sum of a novel real-time programmable analogue first-order low-pass filter. The signal within the circuit remains analogue and is not converted into discrete values. Real-time adjustments are made using digital potentiometers and operational amplifiers. The proposed first-order low-pass filter offers several advantages. In particular, the time constant and DC gain are independently adjusted without relying on the ohmic value of digital potentiometers. The time constant and DC gain depend on the resolution of the digital potentiometers. The high resolution of the digital potentiometer enables the circuit to achieve a wide bandwidth and allows for the use of small capacitors at lower frequencies. The proposed real-time programmable analogue fractional controller is experimented to achieve a fractional integrator. The circuit yields good similarity between theoretical simulations and experimental measurements. © 2023 IEEE. |
Ounis, Walid; Chetoui, Manel; Najar, Salheddine; Aoun, Mohamed Programmable analogue fractional controller realization Conférence 2023. Résumé | Liens | BibTeX | Étiquettes: Analog circuits, Continuous time systems, Controllers, Digital potentiometer, First order, First order low-pass filter, Fractional integrators, Fractional-order controllers, Higher order dynamics systems, Low pass filters, Low-pass filters, Operational amplifiers, Potentiometers (electric measuring instruments), Programmable analog circuit, Programmable analogs, Real- time, Signal processing, Timing circuits @conference{Ounis2023,A fractional-order controller is an infinite-memory system. It is described by a continuous time irrational transfer function. Its realization is a delicate problem especially when its parameters are real time tunable. This paper presents a real-time programmable analogue fractional controller implementation. The controller is based on a sum of a novel real-time programmable analogue first-order low-pass filter. The signal within the circuit remains analogue and is not converted into discrete values. Real-time adjustments are made using digital potentiometers and operational amplifiers. The proposed first-order low-pass filter offers several advantages. In particular, the time constant and DC gain are independently adjusted without relying on the ohmic value of digital potentiometers. The time constant and DC gain depend on the resolution of the digital potentiometers. The high resolution of the digital potentiometer enables the circuit to achieve a wide bandwidth and allows for the use of small capacitors at lower frequencies. The proposed real-time programmable analogue fractional controller is experimented to achieve a fractional integrator. The circuit yields good similarity between theoretical simulations and experimental measurements. © 2023 IEEE. |
2020 |
Atitallah, Halima; Aribi, Asma; Aoun, Mohamed Diagnosis of time-delay fractional systems using observer-based methods Article de journal Dans: International Journal of Dynamical Systems and Differential Equations, vol. 10, no. 2, p. 128 – 148, 2020, (Cited by: 2). Résumé | Liens | BibTeX | Étiquettes: Convergence conditions, Diagnosis, Fault detection, Fault detection and isolation, Fault isolation, Fractional systems, Luenberger observers, Residual sensitivities, Structured residuals, Time delay, Timing circuits, Unknown input observer @article{Atitallah2020128b,In this paper, two model-based methods are considered for the diagnosis of time-delay fractional systems. Time-delay fractional Luenberger observer without unknown input and time-delay fractional unknown input observer are developed and used for fault detection and isolation. A single observer scheme is needed for fault detection and a bank of generalized (respectively dedicated) observers is required for fault isolation. A theoretical study investigating the convergence condition for each observer-based method in terms of matrix inequalities is presented. Residual sensitivities to faults and to disturbances are studied. Time-delay fractional unknown input observer parameters are computed to obtain structured residuals. This observer ensures unknown input decoupling from the state which results residual insensitive to unknown inputs. Two numerical examples to validate the efficiency of the proposed approaches are given. Copyright © 2020 Inderscience Enterprises Ltd. |
Atitallah, Halima; Aribi, Asma; Aoun, Mohamed Diagnosis of time-delay fractional systems using observer-based methods Article de journal Dans: International Journal of Dynamical Systems and Differential Equations, vol. 10, no. 2, p. 128 – 148, 2020, (Cited by: 2). Résumé | Liens | BibTeX | Étiquettes: Convergence conditions, Diagnosis, Fault detection, Fault detection and isolation, Fault isolation, Fractional systems, Luenberger observers, Residual sensitivities, Structured residuals, Time delay, Timing circuits, Unknown input observer @article{Atitallah2020128,In this paper, two model-based methods are considered for the diagnosis of time-delay fractional systems. Time-delay fractional Luenberger observer without unknown input and time-delay fractional unknown input observer are developed and used for fault detection and isolation. A single observer scheme is needed for fault detection and a bank of generalized (respectively dedicated) observers is required for fault isolation. A theoretical study investigating the convergence condition for each observer-based method in terms of matrix inequalities is presented. Residual sensitivities to faults and to disturbances are studied. Time-delay fractional unknown input observer parameters are computed to obtain structured residuals. This observer ensures unknown input decoupling from the state which results residual insensitive to unknown inputs. Two numerical examples to validate the efficiency of the proposed approaches are given. Copyright © 2020 Inderscience Enterprises Ltd. |
2019 |
Atitallah, Halima; Aribi, Asma; Aoun, Mohamed Tracking Control Design for Fractional Systems with Time Delay Conférence 2019, (Cited by: 0). Résumé | Liens | BibTeX | Étiquettes: Automation, Controller parameter, Delay control systems, Fault tolerant control, Fractional systems, Fractional-order systems, Navigation, Numerical methods, Process control, Reference modeling, Time delay, Timing circuits, Tracking controls @conference{Atitallah2019280b,Fault tolerant control has been an important subject for many researchers. Nevertheless, there are few works dealing with fractional systems up to now and especially in presence of time delay. In this context, this paper proposes a tracking control design for fractional order system with time delay. The aim is to control the system in order to obtain the same performances of a time delay fractional reference model. The controller parameters are computed in both nominal and faulty functioning in case the state is available and unavailable for measurement. The efficiency of the proposed method is illustrated through a numerical example. © 2019 IEEE. |
Atitallah, Halima; Aribi, Asma; Aoun, Mohamed Fault estimation using adaptive observer-based technique for time delay fractional-order systems Conférence 2019, (Cited by: 0). Résumé | Liens | BibTeX | Étiquettes: Adaptive observer, Continuous frequency, Convergence criterion, Detection and estimation, Fault detection, Fault estimation, Fractional systems, Fractional-order systems, Linear matrix inequalities, Luenberger observers, Lyapunov functions, Numerical methods, Time delay, Timing circuits @conference{Atitallah2019399b,This paper proposes a technique to detect and estimate faults for fractional-order systems with time delay. Two observers are used in this method. Indeed, a time-delay fractional Luenberger observer is generated to detect fault. An adaptive fractional order with time delay observer is then constructed to estimate the fault by providing an on-line estimation algorithm. The convergence criteria of this observer is expressed via linear matrix inequalities (LMIs) by the use of a specific Lyapunov function considering the continuous frequency disturbed model. The validity of the fault detection and estimation technique is shown by a numerical example. © 2019 IEEE. |
Atitallah, Halima; Aribi, Asma; Aoun, Mohamed Tracking Control Design for Fractional Systems with Time Delay Conférence 2019, (Cited by: 0). Résumé | Liens | BibTeX | Étiquettes: Automation, Controller parameter, Delay control systems, Fault tolerant control, Fractional systems, Fractional-order systems, Navigation, Numerical methods, Process control, Reference modeling, Time delay, Timing circuits, Tracking controls @conference{Atitallah2019280,Fault tolerant control has been an important subject for many researchers. Nevertheless, there are few works dealing with fractional systems up to now and especially in presence of time delay. In this context, this paper proposes a tracking control design for fractional order system with time delay. The aim is to control the system in order to obtain the same performances of a time delay fractional reference model. The controller parameters are computed in both nominal and faulty functioning in case the state is available and unavailable for measurement. The efficiency of the proposed method is illustrated through a numerical example. © 2019 IEEE. |
Atitallah, Halima; Aribi, Asma; Aoun, Mohamed Fault estimation using adaptive observer-based technique for time delay fractional-order systems Conférence 2019, (Cited by: 0). Résumé | Liens | BibTeX | Étiquettes: Adaptive observer, Continuous frequency, Convergence criterion, Detection and estimation, Fault detection, Fault estimation, Fractional systems, Fractional-order systems, Linear matrix inequalities, Luenberger observers, Lyapunov functions, Numerical methods, Time delay, Timing circuits @conference{Atitallah2019399,This paper proposes a technique to detect and estimate faults for fractional-order systems with time delay. Two observers are used in this method. Indeed, a time-delay fractional Luenberger observer is generated to detect fault. An adaptive fractional order with time delay observer is then constructed to estimate the fault by providing an on-line estimation algorithm. The convergence criteria of this observer is expressed via linear matrix inequalities (LMIs) by the use of a specific Lyapunov function considering the continuous frequency disturbed model. The validity of the fault detection and estimation technique is shown by a numerical example. © 2019 IEEE. |
2014 |
Saidi, B.; Amairi, M.; Najar, S.; Aoun, M. Fractional PI design for time delay systems based on min-max optimization Conférence 2014, (Cited by: 7). Résumé | Liens | BibTeX | Étiquettes: Calculations, Constrained optimization, Delay control systems, Design, Differentiation (calculus), Disturbance rejection, First order plus dead time, Fractional calculus, Frequency specifications, Load disturbance rejection, Min-max optimization, Multiobjective optimization, Numerical methods, Numerical optimizations, Robust controllers, System stability, Time delay, Time-delay systems, Timing circuits, Transient analysis @conference{Saidi2014d,This paper presents a new design method of a fractional order PI (FO-PI) for time delay systems based on the min-max numerical optimization. The proposed method uses a constrained optimization algorithm to determine the unknown parameters of the controller and has an objective to improve the transient response, stability margin, stability robustness and load disturbance rejection. A simulation example is presented to show the effectiveness of the proposed design method for a First Order Plus Dead Time system (FOPDT). © 2014 IEEE. |