Valiollah Ghaffari

Valiollah Ghaffari
Persian Gulf University | PGU · Department of Electrical Engineering

Ph. D.

About

35
Publications
1,773
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239
Citations
Additional affiliations
January 2014 - March 2015
Shiraz University
Position
  • Ph. D.
April 2010 - present
Shiraz University
Position
  • PhD Student

Publications

Publications (35)
Article
The transient response improvement is the most crucial feature of the composite nonlinear feedback (CNF) controllers. This study proposes a novel CNF tuning method for systems subject to saturation. To achieve the goals, the linear part is optimally obtained via a performance index and the linear matrix inequality (LMI). Then, employing the passivi...
Article
The integral control is an effective way to track non-zero constant reference. In this paper, to utilize a robust predictive integral control strategy in the output-feedback case, the control requirement and the goals are formulated in a suitable form. Then, by introducing a novel matrix transformation, the controller designing issue is translated...
Article
Full-text available
This study addresses a new delay‐dependent non‐fragile robust model predictive controller for a class of uncertain continuous‐time systems with time‐varying delay subjected to constrained input and perturbed controller gain. The uncertainties in system parameters and controller gain are considered as general additive forms. The proposed controller...
Article
Full-text available
In this study, a robust control technique is investigated for the reference tracking of uncertain time-delayed systems in the existence of the actuator saturation. Due to emerging of some control complexities, as well as the input limitations, time-varying delay, uncertainty, and external disturbance, such a tracking goal would be realized through...
Article
Full-text available
This study proposes an observer-based Composite Nonlinear Feedback (CNF) controller for the robust tracking of uncertain singular systems with input saturation, nonlinear function, time-delay, and disturbances. The suggested control law is designed based states reconstructed using a singular observer so as to increase steady-state accuracy and impr...
Article
Full-text available
This study proposes a composite nonlinear feedback approach for the robust tracking control problem of uncertain nonlinear systems with input saturation, Lipschitz nonlinear functions, multivariable time-delays, and disturbances. The composite nonlinear feedback technique includes two components: a linear feedback portion constructed in such a way...
Article
Full-text available
This paper addresses a robust H∞ integral control scheme for a class of nonlinear uncertain systems. Hence, disturbance rejection and set-point regulation are the main goals in the proposed method, and a state-feedback control design would be employed to satisfy the mentioned aims. Then, a linear matrix inequality (LMI) based procedure would be int...
Article
Full-text available
In this article, a robust H∞ fault tolerant control law is addressed for a class of the uncertain dynamical systems represented via linear fractional transformation. To this objective, a state-feedback controller law is utilized for achieving the control objective. Thus, a linear matrix inequality based performance condition would be derived to gua...
Article
Full-text available
In this paper, a simple robust adaptive sampled-data control law is addressed for a class of uncertain continuous-time systems. For achieving this goal, firstly, the regulation problem and H∞\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \u...
Article
Full-text available
In this research, a novel delay‐dependent composite non‐linear feedback (CNF) control would be pointed for non‐linear time‐delay systems under actuator saturation. For this aim, first, the CNF controller would be formulated in the constrained time‐delay systems. Then, a linear matrix inequality (LMI) approach is presented to obtain the controller p...
Article
A non-fragile robust model predictive control (RMPC) is designed in the uncertain systems under bounded control signals. To this aim, a class of the nonlinear systems with additive uncertainty is considered in its general form. The RMPC synthesis could lead to the proper selection of the controller’s gains. Thus, the non-fragile RMPC design is tran...
Article
Full-text available
A model predictive control (MPC) scheme is mainly developed in discrete-time uncertain systems. The control law contains a dynamic property in the proposed MPC. Hence, the MPC with a dynamic control policy is simply known as model predictive dynamic control (MPDC). To this end, a suitable matrix transformation is suggested to convert the MPDC probl...
Article
Micro Electro Mechanical System (MEMS) gyroscope sensors are used in different underwater vehicles to determine their attitude as the input of the controller system to adjust the attitude to the desired value. Fault detection and elimination are necessary for MEMS gyroscope sensors to avoid disruption of the system performance. In this paper, it is...
Article
The proportional-derivative sliding-mode control will be designed and tuned in the trajectory tracking of a robot manipulator which operates on uncertain dynamic environments. For achieving these goals, first, a linear matrix inequality–based framework is suggested to design a robust proportional-derivative sliding-mode control in the presence of e...
Article
A model predictive method is developed to tune an integral controller for uncertain systems subjected to constrained input signals. For this purpose, a stabilizing integral controller is firstly designed for linear time-invariant (LTI) systems with polytopic uncertainty. The integral controller gains can be determined via a feasible solution of a l...
Article
Full-text available
In this paper, an ANFIS+PID hybrid control policy has been addressed to control a 6 -degree-of freedom (6-DOF) robotic manipulator. Then its error convergence has been also evaluated. The ability to formulate and estimate the system uncertainties and disturbances along with system dynamics and rejecting the disturbances effect are some advantages...
Article
Full-text available
A novel robust model predictive control (RMPC) scheme is developed for uncertain nonlinear systems. To the RMPC design, firstly, the uncertain system would be described using a linear fractional transformation (LFT). Then, regarding the system’s uncertainties and control limitations, a linear matrix inequality (LMI) based control strategy is addres...
Article
A composite nonlinear feedback tracking control is mainly designed via the linear matrix inequality approach in the time-delay nonlinear systems. For achieving this purpose, the composite nonlinear feedback control design is firstly formulated in the nonlinear systems with time-delay. Then, a sufficient stability condition will be addressed in term...
Article
A differential‐free output feedback control law is addressed to stabilize the continuous‐time LTI control systems. For achieving the goal, a state feedback control scheme is firstly designed to meet the predefined control objectives and requirements. Then an output feedback controller would be derived through the Euler’ s backward approximation. Th...
Article
An adaptive robust control scheme is proposed for a class of unknown nonlinear systems. For achieving this purpose, a class of uncertain nonlinear systems is firstly considered. Then, the regulation and tracking problems are solved with the well-known Lyapunov stability theory. It is shown that although the system dynamic may not be fully or partia...
Article
In this paper, master-slave synchronization problem is investigated in the nonlinear systems. For achieving this end, firstly, both states of the master and slave systems are estimated by using of a discrete-time extended Kalman filter. Next with a simple control law, the states of the slave system would be synchronized with the master system state...
Article
In this paper, an LMI framework based on model predictive strategy is addressed to design a robust dynamical control law in a typical control system. In the proposed method, instead of traditional static controller, a dynamic control law is used. With a suitable matrix transformation, the controller parameters selection are translated into an optim...
Article
Purpose The purpose of this paper is to concern the design of a robust model predictive controller for distributed networked systems with transmission delays. Design/methodology/approach The overall system is composed of a number of interconnected nonlinear subsystems with time-varying transmission delays. A distributed networked system with trans...
Article
A reset mechanism in controller can affect the stability property of a closed loop control system. In a simple word, there are stable reset control systems with unstable base-systems and also unstable reset systems with stable base-systems. The Lyapunov stability theory is a strong tool to investigate the stability of a nonlinear system. In this pa...
Article
In reset control systems, the reset law is a main characteristic of the reset controllers. In this study, a model prediction-based framework is proposed to determine a suitable reset law for the uncertain linear control system. For achieving this goal, first a typical uncertain linear plant is considered and then the state space of the closed-loop...
Article
This paper addresses a real-time reset controller design based on the model prediction strategy for process control. Reset control design consists of two main steps: (1) base-system controller design and (2) reset law determination. The base system controller is designed according to the base (no reset) plant dynamics and the reset law is determine...
Article
In a continuous time control system, if some of the controller states are reset, certain limitations on the system response can be removed. Moreover, the stability and performance of such a reset control system may be improved. Resetting action has two main characteristics which should be determined: (a) when the controller states are reset and (b)...
Conference Paper
In this paper, synchronization problem of the Master-Slave chaotic system is presented. To this end, firstly, using discrete time extended Kalman filter, both states of the master and slave systems are estimated, next with a simple control law, slave system states is synchronized with master system states. To show the effectiveness of our approach,...
Conference Paper
This paper presents a linear matrix inequality (LMI) framework to design robust model predictive control (MPC) for a class of continuous-time nonlinear uncertain systems. The controller design is formulated as an optimization problem of the “worst-case” objective function over an infinite moving horizon. A sufficient state feedback synthesis condit...
Article
This paper proposes a robust predictive control approach for additive discrete time uncertain nonlinear systems. The controller design is characterized as an optimization problem of the “worst-case” objective function over an infinite moving horizon. A sufficient state feedback synthesis condition is provided in the form of a linear matrix inequali...
Article
Full-text available
This paper addresses two control schemes for stochastic nonlinear systems. Firstly, an adaptive controller is designed for a class of motion equations. Then, a robust finite-time control scheme is proposed to stabilize a class of nonlinear stochastic systems. The stability of the closed-loop systems is established based on stochastic Lyapunov stabi...
Conference Paper
This paper presents a new approach for design of a digital phase locked loop. By employing a digitally controlled oscillator (DCO) and a time-to-digital converter (TDC), the loop filter of a DPLL becomes all-digital. Instead of designing the loop filter by digitizing a continuous-time loop response as has been commonly done, more sophisticated cont...
Article
This paper proposes a new adaptive method to control a class of nonlinear discrete systems. For this purpose, the special type of nonlinear system is considered first, it is shown that by using discrete time Lyapunov theory we can derive a suitable control law so that the closed loop system will be asymptotically stable, in the sense of Lyapunov. F...
Conference Paper
This paper addresses a robust predictive control of additive discrete time uncertain nonlinear systems. The controller design is characterized as an optimization problem of the “worst-case” objective function over an infinite moving horizon. A sufficient state feedback synthesis condition is provided in the form of a linear matrix inequality (LMI)...

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Project
ISEDS at Persian Gulf University (PGU) has pioneered many of the tools and ideas behind the research and applications often classified as "intelligent systems" and “data science,” where computer science, electrical engineering, statistics, and mathematics join together. This Faculty sees an even brighter future for data science as it harnesses a wider set of ideas to build a new more subtle and powerful science of data. As well as being interested in prediction and statistical computation, our Faculty puts equal weight on designing experiments, modeling sophisticated dependencies (networks, data streams), and trying to understand and quantify causal mechanisms, not simply averages and associations, with large data sets. These views are reflected in our curriculum targeted to data science specialists, our faculty’s research, and the work of our research students.