Robust Control of Nonlinear Fractional-Order Systems with Unknown Upper Bound of Uncertainties and External Disturbance

2021 ◽  
pp. 1-12
Author(s):  
Amin Emamifard ◽  
Hamid Ghadiri
Keyword(s):  
Robust Control ◽  
Fractional Order ◽  
Upper Bound ◽  
External Disturbance ◽  
Fractional Order Systems

Adaptive robust control of fractional-order systems with matched and mismatched disturbances

2019 ◽  
Vol 162 ◽  
pp. 85-96 ◽  
Author(s):  
Aldo Jonathan Muñoz-Vázquez ◽  
Manuel Benjamín Ortiz-Moctezuma ◽  
Anand Sánchez-Orta ◽  
Vicente Parra-Vega
Keyword(s):  
Robust Control ◽  
Fractional Order ◽  
Adaptive Robust Control ◽  
Fractional Order Systems ◽  
Mismatched Disturbances

Robust adaptive sliding mode control combination with iterative learning technique to output tracking of fractional-order systems

2017 ◽  
Vol 40 (6) ◽  
pp. 1808-1818 ◽  
Author(s):  
Ehsan Ghotb Razmjou ◽  
Seyed Kamal Hosseini Sani ◽  
Jalil Sadati
Keyword(s):  
Fractional Order ◽  
Iterative Learning Control ◽  
Sliding Mode ◽  
External Disturbance ◽  
Learning Control ◽  
Iterative Learning ◽  
Adaptive Sliding Mode Control ◽  
Order System ◽  
Control Input ◽  
Fractional Order Systems

This paper develops a novel controller called adaptive iterative learning sliding mode (AILSM) to control linear and nonlinear fractional-order systems. This controller applies a hybrid structure of adaptive and iterative learning control in to sliding mode method. It can switch between both adaptive and iterative learning control in order to use the advantages of both controllers simultaneously and therefore achieve better control performance. This controller is designed in a way to be robust against the external disturbance. It also estimates unknown parameters of fractional-order system. The proposed controller, unlike the conventional iterative learning control, does not need to apply direct control input to output of the system. It is shown that the controller performs well in partial and complete observable conditions. Illustrative examples verify the performance of the proposed control in presence of unknown disturbances and model uncertainties.

scholarly journals Robust Control of Doubly Fed Induction Generator Using Fractional Order Control

2018 ◽  
Vol 9 (3) ◽  
pp. 1072 ◽  
Author(s):  
Abdelaziz Azza ◽  
Hamid Kherfane
Keyword(s):  
Robust Control ◽  
Fractional Order ◽  
Design Method ◽  
External Disturbance ◽  
Maximum Power ◽  
Critical Conditions ◽  
Induction Generator ◽  
Doubly Fed Induction Generator ◽  
Fractional Order Control ◽  
Doubly Fed

In this paper, we present a robust control of a variable speed Doubly Fed Induction Generator (DFIG)-based Wind Energy Conversion System (WECS), using Fractional Order Control (FOC) to prevent system deterioration under different critical conditions (external disturbance, measurement noise and DFIG parameters variation). In order to extract the maximum power from the wind, a Maximum Power Point Tracking (MPPT) strategy based on rotor speed control is proposed. Furthermore, a vector control strategy is used for controlling active and reactive powers of DFIG. Additionally, a simple design method of Fractional Order Proportional Integral (FOPI) controller is proposed. Finally, the system’s performance is tested and compared according to reference tracking, robustness, disturbance rejection and noise minimization.

Fractional-Order Nonlinear Disturbance Observer Based Control of Fractional-Order Systems

2018 ◽  
Vol 13 (7) ◽  
Author(s):  
Aldo Jonathan Muñoz-Vázquez ◽  
Vicente Parra-Vega ◽  
Anand Sánchez-Orta
Keyword(s):  
Robust Control ◽  
Fractional Order ◽  
Finite Time ◽  
Disturbance Observer ◽  
Continuous Control ◽  
Fractional Order Systems ◽  
Sliding Modes ◽  
Nonlinear Disturbance Observer ◽  
Nonlinear Disturbance ◽  
Dynamic Observer

The robust control for a class of disturbed fractional-order systems is presented in this paper. The proposed controller considers a dynamic observer to exactly compensate for matched disturbances in finite time, and a procedure to compensate for unmatched disturbances is then derived. The proposed disturbance observer is built upon continuous fractional sliding modes, producing a fractional-order reaching phase, leading to a continuous control signal, yet able to reject for some continuous but not necessarily differentiable disturbances. Numerical simulations and comparisons are presented to highlight the reliability of the proposed scheme.

Robust Stability Analysis of Uncertain Linear Fractional-Order Systems With Time-Varying Uncertainty for 0 < α < 2

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Mohammad Tavazoei ◽  
Mohammad Hassan Asemani
Keyword(s):  
Stability Analysis ◽  
Fractional Order ◽  
Robust Stability ◽  
Stability Condition ◽  
Upper Bound ◽  
Order System ◽  
Time Varying ◽  
Fractional Order Systems ◽  
Robust Stability Analysis ◽  
The Stability

This paper focuses on the stability analysis of linear fractional-order systems with fractional-order 0<α<2, in the presence of time-varying uncertainty. To obtain a robust stability condition, we first derive a new upper bound for the norm of Mittag-Leffler function associated with the nominal fractional-order system matrix. Then, by finding an upper bound for the norm of the uncertain fractional-order system solution, a sufficient non-Lyapunov robust stability condition is proposed. Unlike the previous methods for robust stability analysis of uncertain fractional-order systems, the proposed stability condition is applicable to systems with time-varying uncertainty. Moreover, the proposed condition depends on the fractional-order of the system and the upper bound of the uncertainty matrix norm. Finally, the offered stability criteria are examined on numerical uncertain linear fractional-order systems with 0<α<1 and 1<α<2 to verify the applicability of the proposed condition. Furthermore, the stability of an uncertain fractional-order Sallen–Key filter is checked via the offered condition.

scholarly journals Adaptive Neural Backstepping Control of Nonlinear Fractional-Order Systems with Input Quantization

2021 ◽  
Author(s):  
Chao Cheng ◽  
Huanqing Wang ◽  
Haikuo Shen ◽  
Peter Xiaoping Liu
Keyword(s):  
Fractional Order ◽  
Tracking Control ◽  
Disturbance Observer ◽  
External Disturbance ◽  
Rbf Neural Networks ◽  
Fractional Order Systems ◽  
Backstepping Method ◽  
Input Quantization ◽  
Lyapunov Stability Analysis ◽  
Simulation Results

Abstract This article addresses the tracking control problem of uncertain fractional-order nonlinear systems in the presence of input quantization and external disturbance by combining with radial basis function(RBF) neural networks(NNs), fractional-order disturbance observer(FODO) and backstepping method. The unknown nonlinearities of fractional-order systems is approximated by RBF NNs. The design of hysteretic quantizer achieves quantification of input signal and avoids chattering. The FODO is utilized to evaluate the external disturbance exist in fractional-order systems. According to fractioanlorder Lyapunov stability analysis, the bounds of all the signals in the closedloop system is proved. The effectiveness of the proposed method is confirmed by the simulation results.

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