Controllability Of Fractional Systems Research Articles

Controllability of partially observed stochastic semilinear fractional control systems

Controllability of partially observed stochastic semilinear fractional control systems

On Partial Exact Controllability of Fractional Control Systems in Conformable Sense

In this work, we investigate the partial exact controllability of fractional semilinear control systems in the sense of conformable derivatives. Initially, we establish the existence and uniqueness of the mild solution for this type of fractional control systems. Then, by employing a contraction mapping principle, we obtain sufficient conditions for the conformable fractional semilinear system to be partially exactly controllable, assuming that its associated linear part is partially exactly controllable. To demonstrate the efficacy of the theoretical findings, a typical example is provided at the end.

Results on partial approximate controllability of fractional control systems in Hilbert spaces with conformable derivatives

This paper investigates partial approximate controllability of fractional linear and semi-linear control systems involving the conformable derivative. First, we derive sufficient and necessary conditions for partial approximate controllability of fractional linear systems over a small interval. Then, we apply a new approach, different from typical methods involving complexity inequalities and fixed point theorems, to obtain sufficient conditions for partial approximate controllability of semi-linear fractional control systems, assuming that the linear part is partially approximately controllable. The effectiveness of these results is demonstrated through an illustrative example.

A General Design Methodology for Fractional Cascade Control Systems

A General Design Methodology for Fractional Cascade Control Systems

An improved repetitive controller with fractional time-delay for discrete-time linear systems: Synthesis and comparison study

This paper develops a discrete-time repetitive control (RC) system with a fractional-delay internal model. Unlike the conventional RC, the time delay for constructing the internal model is not necessarily an integer, implying that the time delay is allowed to be fractional. In this work, a fractional delay-based repetitive control system is presented. Firstly, the fractional time delay is calculated based on the information of the reference or disturbance along with the associated sampling period. Secondly, the fractional time delay is divided into two parts, i.e., the large integer and small fractional delays. Finally, the fractional part is realized by a stable and causal infinite impulse response (IIR) filter, whose coefficients are calculated using the Thiran formula. The controller structure and stability analysis are developed for three different RCs, namely a fractional-delay general RC (FD-GRC), a fractional delay-odd harmonics RC (FD-OHRC), and a fractional delay-(6l±1) RC (FD-(6l±1)RC). Experiments and comparison studies of the integer delay-based RCs are conducted to verify the effectiveness and improved tracking accuracy of the proposed method.

On the Dynamics of Two-Dimensional Fractional Linear Control Systems

On the Dynamics of Two-Dimensional Fractional Linear Control Systems

Fractional optimal control strategies for hepatitis B virus infection with cost-effectiveness analysis

Hepatitis B disease is a communicable disease that is caused by the hepatitis B virus and has become a significant health problem in the world. It is a contagious disease that is transmittable from person to person either horizontally or vertically. This current study is aimed at sensitivity analysis and optimal control strategies for a fractional hepatitis B epidemic model with a saturated incidence rate in the sense of the Caputo order fractional derivative approach. Fundamental properties of the proposed fractional order model are obtained and discussed. A detailed analysis of disease-free equilibrium and endemic equilibrium points is given by applying fractional calculus theory, which is a generalized version of classical calculus. Sensitivity indexes are calculated for the classical order model. Illustrative graphics that show the dependence of the sensitivity index on fractional order derivative for alpha in (0,1) are provided. Based on the results of the sensitivity analysis and using Pontryagin’s Maximum Principle, optimal control strategies for preventing hepatitis B infection with vaccination and treatment are considered. Fractional Euler’s method is used to carry out the numerical simulation for the proposed fractional optimal control system and the obtained results are analyzed. The results of the analysis reveal that hepatitis B disease can be prevented if necessary precautionary is taken or effective vaccination and treatment control measures are applied. The analysis of cost-effectiveness is also conducted and discussed.

Controllability of fractional dynamical systems having multiple delays in control with ψ‐Caputo fractional derivative

This study investigates the controllability problems for linear and nonlinear fractional control systems with multiple control delays in the context of the ‐Caputo fractional derivative. For the linear case, using the positive definiteness of the Gramian matrix, the necessary and sufficient conditions are obtained. For the nonlinear case, utilizing the iterative technique together with the completeness of the space, sufficient conditions for the existence of a solution are obtained. Just a few examples are included to make theoretical findings easier to grasp, and their respective graphs are plotted.

GWO based Robust Stabilization of DC Motor Fractional Order Speed Control System with Interval Coefficients

Robust stability analysis (RSA) is of significant concern for the robust behaviour of real-world control system applications. A stabilization strategy that assures stability and exhibits robust performance for a specified limit of system perturbations is necessary. This article presents an optimal robust stabilization method for a closed loop fractional order proportional integral derivative (FOPI^λD^µ) system involving DC motor with interval parametric uncertainty. To determine the optimum value of parameters for a FOPI^λD^µ controller to control the speed of a DC motor, Grey Wolf Optimizer (GWO), Genetic Algorithm (GA), Nelder-Mead (NM), Jaya and Whale Optimizer Algorithm (WOA) are applied with the same objective function involving ITAE criterion. FOPI^λD^µ offers two additional tuning parameters unlike a nominal PID controller and hence the former gives more flexibility in controller design than the latter in terms of transient response. The FOPID controller provides a faster closed-loop output augmented with improved robust properties of the system. Despite inherent non-linearities and time variation in system parameters, FOPI^λD^µ controllers depict enhanced performance. Using the concept of conformal mapping, robust stability analysis of fractional order polynomials is done with uncertain interval structure using Vertex and Edge theorem. Based on the value set, this paper demonstrates numerical and graphical optimal robust stability analysis of a system with variations observed in five parameters, considering the minimum argument root of the polynomial of the aforementioned closed-loop system.

Stability and Optimal Control of a Fractional SEQIR Epidemic Model with Saturated Incidence Rate

The fractional differential equation has a memory property and is suitable for biomathematical modeling. In this paper, a fractional SEQIR epidemic model with saturated incidence and vaccination is constructed. Firstly, for the deterministic fractional system, the threshold conditions for the local and global asymptotic stability of the equilibrium point are obtained by using the stability theory of the fractional differential equation. If R0<1, the disease-free equilibrium is asymptotically stable, and the disease is extinct; when R0>1, the endemic equilibrium is asymptotically stable and the disease persists. Secondly, for the stochastic system of integer order, the stochastic stability near the positive equilibrium point is discussed. The results show that if the intensity of environmental noise is small enough, the system is stochastic stable, and the disease will persist. Thirdly, the control variables are coupled into the fractional differential equation to obtain the fractional control system, the objective function is constructed, and the optimal control solution is obtained by using the maximum principle. Finally, the correctness of the theoretical derivation is verified by numerical simulation.

Existence and approximate controllability of Riemann-Liouville fractional evolution equations of order 1 < μ < 2 with weighted time delay

This article demonstrates the existence as well as the approximate controllability of semilinear fractional control systems governed by the μ∈(1,2)-order Riemann-Liouville fractional evolution equation with weighted time delay. Firstly, properties of the cosine family and the corresponding sine family are proved. Then an existence result is achieved for the concerned problem by utilizing fixed point theorem approach. The approximate controllability is also studied under essential conditions. Finally, we propose an example of the obtained abstract result.

Approximate Controllability of Fractional Stochastic Evolution Inclusions with Non-Local Conditions

This article investigates the approximate controllability of non-linear fractional stochastic differential inclusions with non-local conditions. We establish a set of sufficient conditions for their approximate controllability and provide results in terms of controllability for the fractional stochastic control system. Our approach relies on using fractional calculus and the fixed-point theorem for multiple-valued operators. Finally, we present an illustrative example to support our findings.

Optimal Controls for Fractional Backward Nonlocal Evolution Systems

This article analyzes a Caputo type fractional backward nonlocal evolution control system. By means of a joint combination of resolvent theory with the approximation solvability technique, we dispense with the compactness assumption on the semigroup and the Lipschitz restriction on the nonlinear term when we treat the existence of solutions. Furthermore, we launch a new method of formulating minimizing sequences twice and the weak topology technique to explore the optimal control problem (OP). Finally, the plausibility of our mentioned results is supported by a simple application.

Singular fuzzy fractional quadratic regulator problem

This study aims to create a fuzzy optimal control system for a singular fuzzy fractional quadratic regulator problem, which is governed by singular fuzzy fractional differential equations. Additionally, this paper introduces new terms such as fuzzy stability, asymptotic stability, stabilizability, and detectability in the context of singular fractional control systems. Theoretical concepts regarding the stabilizability and detectability of these systems are also outlined, as well as a theorem and related algorithm for determining the fuzzy optimal control and trajectory of the singular fuzzy fractional quadratic regulator problem. The proposed method is tested through simulation on an electrical circuit modeled as a singular fuzzy fractional system, with results demonstrating the efficacy of the approach.

Results on the Approximate Controllability of Hilfer Type fractional Semilinear Control Systems

Results on the Approximate Controllability of Hilfer Type fractional Semilinear Control Systems

Granular-based state estimation for nonlinear fractional control systems and its circuit cognitive application

The issue of continuous observer design for integer order nonlinear systems has been widely studied in existing works. Yet, there are few works that closely related to granular computing theory and discrete signal to better estimate system states. In this paper, by using the granular function description, we propose a novel impulsive observer design algorithm to ensure the cognitive convergence of error dynamic systems. Especially, the resulting criterion reflects well the relationship between the fractional order and the pulse signal. A numerical simulation is provided to illustrate effectiveness of the given method.

Topological Structure of Solution Sets of Fractional Control Delay Problem

This paper is concerned with the existence of a mild solution for the fractional delay control system. Firstly, we will study the control problem. Then, we will deal with the topological structure of the solution set consisting of the compactness and Rσ property. We will derive a mild solution to the above delay control problem by using the Laplace transform method.

Relaxation in nonconvex optimal control problems described by evolution Riemann-Liouville fractional differential inclusions

&lt;p style='text-indent:20px;'&gt;In this paper, we are concerned with the minimization problem of an integral functional with integrand that is not convex in the control on solutions of a Riemann-Liouville fractional differential control system with mixed nonconvex feedback constraints on the control. At First, the existence results for Riemann-Liouville fractional semilinear differential control systems are discussed by using Schauder's fixed point theorem. Under some reasonable assumptions, we prove that the relaxation problem has an optimal solution, and that for each optimal solution there has a minimizing sequence of the original problem that converges to the optimal solution with respect to the trajectory, the control, and the functional in appropriate topologies simultaneously. Finally, we give an example to illustrate our main results.&lt;/p&gt;

Atangana–Baleanu Semilinear Fractional Differential Inclusions With Infinite Delay: Existence and Approximate Controllability

Abstract The main focus of this paper is centered around approximate controllability results of Atangana–Baleanu fractional differential systems with infinite delay. Using principles and ideas from the theory of multivalued maps, fractional calculus, and Bohnenblust–Karlin fixed point techniques, the key findings are established. We begin by emphasizing the existence of mild solutions, and then demonstrate the approximate controllability of the Atangana–Baleanu fractional control system. We then apply our findings to the theory of the neutral system.

Regional Controllability and Minimum Energy Control of Delayed Caputo Fractional-Order Linear Systems

We study the regional controllability problem for delayed fractional control systems through the use of the standard Caputo derivative. First, we recall several fundamental results and introduce the family of fractional-order systems under consideration. Afterward, we formulate the notion of regional controllability for fractional systems with control delays and give some of their important properties. Our main method consists of defining an attainable set, which allows us to prove exact and weak controllability. Moreover, the main results include not only those of controllability but also a powerful Hilbert uniqueness method, which allows us to solve the minimum energy optimal control problem. More precisely, an explicit control is obtained that drives the system from an initial given state to a desired regional state with minimum energy. Two examples are given to illustrate the obtained theoretical results.