Adaptive Fuzzy Fractional-order Fast Terminal Sliding Mode Control for a Class of Uncertain Nonlinear Systems (original) (raw)
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IETE Journal of Research, 2020
The paper introduces a novel adaptive neural network fractional-order nonsingular terminal sliding mode controller using conformable fractional-order (CFO) derivative for a class of uncertain nonlinear systems. For this purpose, a new conformable fractional-order nonlinear sliding surface is proposed and the corresponding control law is designed using Lyapunov stability theorem in order to satisfy the sliding condition in finite time. To deal with uncertainties, the lumped uncertainty is approximated by neural networks and adaptation laws are designed using Lyapunov stability concept. As adaptive neural network uses small switching control gain in the presence of large time varying uncertainties the chattering phenomenon is omitted. The proposed adaptive neural network conformable fractional-order nonsingular terminal sliding mode controller (ANN-CFONTSMC) exhibits better control performance, guaranties finite-time convergence and robust stability of the closed-loop control system. Finally, the effectiveness of the proposed controller is illustrated through the numerical simulations.
Soft Computing
An adaptive fractional-order sliding mode control (AFOSMC) is proposed to control a nonlinear fractional-order system. This scheme combines the features of sliding mode control and fractional control for improving the response of nonlinear systems. The structure of AFOSMC includes two units: fractional-order sliding mode control (FOSMC) and the tuning unit that employs a certain Takagi–Sugeno–Kang fuzzy logic system for online adjusting the parameters of FOSMC. Tuning the parameters of the FOSMC improves its performance with various control problems. Moreover, stability analysis of the proposed controller is studied using Lyapunov theorem. Finally, the developed control scheme is introduced for controlling a fractional-order gyroscope system. The proposed AFOSMC is implemented practically using a microcontroller where the test is carried out using the hardware-in-the-loop simulation. The practical results indicate the improvements and enhancements introduced by the developed control...
International Journal of Automation and Control, 2019
In this paper, a novel terminal sliding manifold is introduced. Then, based on new sliding surface, we proposed two new fast converging robust controllers. The first controller is a fractional terminal sliding mode controller for a class of fractional order chaotic system in order to decrease singularity problem as well increasing fast convergence. Stability analysis of the system has been proved by Lyapunov stability theorem. The second one is the fractional dynamic terminal sliding mode controller for a class of fractional second order chaotic system so as to reduce chattering problem. For each, numerical simulations have been done to show the applicability and effectiveness of the proposals.
Adaptive fractional‐order non‐singular fast terminal sliding mode control for robot manipulators
IET Control Theory & Applications, 2016
In this paper, an adaptive fractional-order terminal sliding mode controller (FO-TSMC) is proposed for controlling robot manipulators with uncertainties and external disturbances. An adaptive tuning method is utilized to deal with uncertainties which upper bounds are unknown in practical cases. Fast convergence is achieved by using non-singular fast terminal sliding mode control. Also, fractionalorder controller is used to improve tracking performance of controller. After proposing a new stable fractional-order non-singular and nonlinear switching manifold, a sliding mode control law is designed. The stability of the closed-loop system is proved by Lyapunov stability theorem. Simulation results demonstrate the effectiveness and high-precision tracking performance of this controller in comparison with integer-order terminal sliding mode controllers. IET Review Copy Only IET Control Theory & Applications This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication in an issue of the journal. To cite the paper please use the doi provided on the Digital Library page.
Design of Fractional Order Sliding Mode Controller for a class of nonlinear systems
2018
In this article, a novel nonlinear sliding mode controller is proposed to control a class of nonlinear systems. The proposed control scheme is based on conformable fractional order operators. The stability analysis is performed using Lyapunov direct method. Simulation results show high convergence speed, chattering reduction and small control effort.
Aerospace Science and Technology, 2015
An adaptive fuzzy fractional order sliding mode control (FFOSMC) is introduced for a high performance servo actuation system that is subjected to aerodynamic loads and uncertainties. During flight, aerodynamic loads are exerted on control surfaces which directly affect the performance of position servo loop. Moreover, since these loads are not linear so qualification of servo actuators is an important process in aerospace industry. This article focuses on formulating a servo position controller using fractional calculus and verifying its performance under system uncertainties, nonlinear friction and aerodynamic loads. Utilizing the advantages of fractional order proportional-integral PIα sliding surface and fractional order proportional-derivative PDλ sliding surface, a novel sliding surface is proposed. To reduce chattering phenomenon in sliding mode control, fuzzy logic controller (FLC) is used to deal with uncertain nonlinearities, parametric uncertainties and external disturbances. FLC makes it possible to use small switching gain of the discontinuous control in the presence of large upper bounded uncertainties. Adaptive laws are formulated using Lyapunov function to guarantee the sliding condition. Efficiency of the proposed controller is demonstrated through numerical simulations.
Adaptive Fractional Order Sliding Mode Control for a Nonlinear System
2021 International Conference on Electronic Engineering (ICEEM), 2021
In this study, an adaptive fractional order sliding mode controller with a neural estimator is proposed for a class of systems with nonlinear disturbances. Compared with traditional sliding mode controller, the new proposed fractional order sliding mode controller contains a fractional order term in the sliding surface. The fractional order sliding surface is used in adaptive laws which are derived in the framework of Lyapunov stability theory. The bound of the disturbances is estimated by a radial basis function neural network to relax the requirement of disturbance bound. To investigate the effectiveness of the proposed adaptive neural fractional order sliding mode controller, the methodology is applied to a Z-axis Micro-Electro-Mechanical System (MEMS) gyroscope to control the vibrating dynamics of the proof mass. Simulation results demonstrate that the proposed control system can improve tracking performance as well as parameter identification performance.
An Adaptive-Fuzzy Fractional-Order Sliding Mode Controller Design for an Unmanned Vehicle
Elektronika ir Elektrotechnika, 2018
In this paper, speed and direction angle of a four wheel skid-steered mobile robot (4 WD SSMR) has been controlled via adaptive-fuzzy fractional-order sliding mode controller (AFFOSMC) under different speed and angle reference signals. The hybrid control method is designed to combine all advantages that controllers have such as flexibility realized by fractional order calculation, robustness to disturbances and parameters variations provided by sliding mode controller (SMC) as well as adaptation of G constant of SMC via fuzzy controller, simultaneously. Also, a fractionalorder SMC is applied to the system for the same reference speed and angle references to show the effects of the changes and adaptation of G constant. Experimental results show that the AFFOSMC has better trajectory tracking performance than the FOSMC.
Sliding-Mode Controller Based on Fractional Order Calculus for a Class of Nonlinear Systems
International Journal of Electrical and Computer Engineering (IJECE)
This paper presents a new approach of fractional order sliding mode controllers (FOSMC) for a class of nonlinear systems which have a single input and two outputs (SITO). Firstly, two fractional order sliding surfaces S1 and S2 were proposed with an intermediate variable z transferred from S2 to S1 in order to hierarchy the two sliding surfaces. Secondly, a control law was determined in order to control the two outputs. A sliding control stability condition was obtained by using the properties of the fractional order calculus. Finally, the effectiveness and robustness of the proposed approach were demonstrated by comparing its performance with the one of the conventional sliding mode controller (SMC), which is based on integer order derivatives. Simulation results were provided for the case of controlling an inverted pendulum system.
A novel continuous fractional sliding mode control
International Journal of Systems Science, 2017
A new fractional-order controller is proposed, whose novelty is twofold: (i) it withstands a class of continuous but not necessarily differentiable disturbances as well as uncertainties and unmodelled dynamics, and (ii) based on a principle of dynamic memory resetting of the differintegral operator, it is enforced an invariant sliding mode in finite time. Both (i) and (ii) account for exponential convergence of tracking errors, where such principle is instrumental to demonstrate the closed-loop stability, robustness and a sustained sliding motion, as well as that high frequencies are filtered out from the control signal. The proposed methodology is illustrated with a representative simulation study.