Search for: input-non-linearities
Article 2014 IEEE Conference on Control Applications ; 2014 , PP. 1035-1040 ; ISBN: 9781479974092 ; Haeri, M ; Sharif University of Technology
This paper deals with the synchronization of two Lur'e differential inclusions containing sector nonlinearity. Lyapunov stability theorem is employed to design the control inputs. The controllers are designed considering three important practical features in physical systems. First, differential equation part of the Lur'e differential inclusion is assumed to be convex. Second, it is presumed that parameters of the Lur'e differential inclusion are not completely known. Third, sector nonlinearities are considered on control inputs applied to the Lur'e differential inclusions. To assess performance and effectiveness of the proposed controllers, synchronization of two rotor dynamic systems is...
Stabilisation of commensurate fractional-order polytopic non-linear differential inclusion subject to input non-linearity and unknown disturbances, Article IET Control Theory and Applications ; Volume 7, Issue 12 , 2013 , Pages 1624-1633 ; 17518644 (ISSN) ; Haeri, M ; Sharif University of Technology
In this study, a fractional-order adaptive-sliding mode control (SMC) scheme is proposed to stabilise commensurate fractional-order polytopic non-linear differential inclusion systems containing sector and dead-zone nonlinearities in the control inputs and unknown bounded disturbances. The suggested control method is composed of fractional-order sliding surfaces, adaptive-SMC inputs and adaptation laws for unknown bounds of disturbances. The Lyapunov stability theorem is used to prove the stability of the closed-loop system. A practical system and two numerical examples are simulated to show the effectiveness and performance of the proposed control technique
Adaptive prescribed performance control of switched MIMO uncertain nonlinear systems subject to unmodeled dynamics and input nonlinearities, Article International Journal of Robust and Nonlinear Control ; Volume 28, Issue 18 , 2018 , Pages 5981-5996 ; 10498923 (ISSN) ; Shahrokhi, M ; Vafa, E ; Moradvandi, A ; Sharif University of Technology
In this paper, the design of an adaptive tracking control for a class of switched uncertain multiple-input–multiple-output nonlinear systems in the strict-feedback form with unmodeled dynamics in the presence of three types of input nonlinearity under arbitrary switching has been addressed. By means of an intelligent approximator like a fuzzy logic system or a neural network, the unknown dynamics are estimated. The unmodeled dynamics have been tackled with a dynamic signal. A universal framework for describing different types of input nonlinearity including saturation, backlash, and dead zone has been utilized. By applying the backstepping approach and the common Lyapunov function method,...
Adaptive finite-time neural control of non-strict feedback systems subject to output constraint, unknown control direction, and input nonlinearities, Article Information Sciences ; Volume 520 , 2020 , Pages 271-291 ; Shahrokhi, M ; Mohit, M ; Sharif University of Technology
Elsevier Inc 2020
This paper addresses the finite-time controller design for a class of nonlinear systems in the non-strict feedback form subject to unknown system dynamics and disturbances, arbitrary asymmetric time-varying output constraints, four types of input nonlinearities, and unknown control direction. Utilizing the barrier Lyapunov function (BLF) and backstepping technique, an adaptive finite-time controller has been proposed. The difficulties associating with non-strict feedback systems have been handled using the variable separation approach. Furthermore, the unknown control direction problem has been tackled by using the Nussbaum gain function. A unified framework has been utilized for handling...
Adaptive finite-time fault-tolerant controller for a class of uncertain MIMO nonlinear switched systems subject to output constraints and unknown input nonlinearities, Article Nonlinear Analysis: Hybrid Systems ; Volume 35 , February , 2020 ; Malek, S. A ; Shahrokhi, M ; Sharif University of Technology
Elsevier Ltd 2020
In this work, design of an adaptive finite-time fault-tolerant controller for a class of uncertain multi-input multi-output (MIMO) nonlinear switched systems with unmodeled dynamics subject to asymmetric time-varying output constraints and unknown faulty input nonlinearities has been addressed. The number of actuator faults can be infinite. In addition, the proposed control algorithm can cope with different unknown types of input nonlinearities namely, saturation, dead zone, backlash, and hysteresis. Actuator faults and input nonlinearities can be different in different modes. To estimate the system uncertainties, neural networks (NNs) have been employed and the unmodeled dynamics has been...
Article Industrial and Engineering Chemistry Research ; Volume 59, Issue 43 , 2020 , Pages 19370-19382 ; Shahrokhi, M ; Ibeas, A ; Sharif University of Technology
American Chemical Society 2020
In this study, an impulsive state feedback controller has been proposed for the treatment of hepatitis-C-infected patients under Pegylated-Interferon (PEG-IFN-α2b) therapy. The Neumann model has been utilized as the representative of the hepatitis C virus (HCV) dynamics. In order to consider the drug efficacy variation between injections, the pharmacokinetics/pharmacodynamics (PK/PD) equations have been included in the model. The impulsive nature of the drug injection also has been considered in the disease dynamics. In the proposed treatment method, the drug dose limitation has been addressed as an input nonlinearity. The asymptotical stability of the control method under the impulsive...