Department of Control (2012 - Present)
Control engineering
, Tarbiat Modares University,
Control engineering
, Tarbiat Modares University,
Electrical Engineering - Electronics
, Urmia University,
Research field: From Sensor Signals to Health-related Data, From Health-related Data to Advanced Diagnosis Insights
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Research field: Optimization and classic control: Robust methods, convex optimization, Complex Systems, ...
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Research field: Designing and producing diagnostic and research kits based on AI and systems Biology
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Mahdi Sojoodi received the B.Sc. degree in electrical engineering from Urmia University in 2002, and the M.Sc. and Ph.D. degrees in electrical engineering from Tarbiat Modares University, Tehran, Iran in 2005 and 2010 respectively. He joined Tarbiat Modares University in 2011 where he is teaching control theory and optimization courses. His research interests are in classic control and optimization applied to multi-agent and complex systems, systems biology, health control, syber-physical systems, and emerging multidisciplinary areas.
The aim of this paper is to control a fractional-order system with model predictive controller by using numerical calculations. In this article, we propose a numerical method based on the Mittag-Leffler function for obtaining the step response of the fractional-order system, then a dynamic matrix controller (DMC) is designed for a multivariate fractional-order system, which is a two-input and two-output system to show the effect of the controller. To perform better tracking and small overshoot the constrained DMC is used. Constraints are based on limiting the outputs and control efforts. The numerical calculations and the controllers design are developed using MATLAB tool. Finally, it is shown that a fractional-order system can be controlle
Objective: We present a four-branch model of the dielectrophoresis (DEP) method that takes into consideration the inherent properties of particles, including size, electrical conductivity, and permittivity coefficient. By using this model, bioparticles can be continuously separated by the application of only a one-stage separation process. Materials and Methods: In this numerical study, we based the separation process on the differences in the particle sizes. We used the various negative DEP forces on the particles caused by the electrodes to separate them with a high efficiency. The particle separator could separate blood cells because of their different sizes. Results: Blood cells greater than 12 μm were guided to a special branch, which
This study proposes a microfluidic device capable of separating monocytes from a type of cancer cell that is called T-cell acute lymphoblastic leukemia (RPMI-8402) in a continuous flow using negative and positive dielectrophoretic forces. The use of both the hydrodynamic and dielectrophoretic forces allows the separation of RPMI-8402 from monocytes based on differences in their intrinsic electrical properties and sizes. The specific crossover frequencies of monocytes and RPMI-8402 cells have been obtained experimentally. The optimum ranges of electrode pitch-to-channel height ratio at the cross sections with different electrode widths have been generally calculated by numerical simulations of the gradients of the electric field intensities
This paper deals with the problem of robust dynamic output feedback stabilization of interval fractional-order linear time invariant (FO-LTI) systems with the fractional order . In this study, a new formulation based on the null-space analysis of the system matrices is proposed using linear matrix inequalities (LMIs). The applied uncertain model is the most complete model of linear interval systems, in which all of the systems matrices are interval matrices. A robust dynamic output feedback controller is designed that asymptotically stabilizes the interval FO-LTI system, where no limiting constraint is assumed on the state space matrices of the uncertain system. Eventually, a numerical example with simulations is presented to demonstrate th
Objective: We present a four-branch model of the dielectrophoresis (DEP) method that takes into consideration the inherent properties of particles, including size, electrical conductivity, and permittivity coefficient. By using this model, bioparticles can be continuously separated by the application of only a one-stage separation process.Materials and Methods: In this numerical study, we based the separation process on the differences in the particle sizes. We used the various negative DEP forces on the particles caused by the electrodes to separate them with a high efficiency. The particle separator could separate blood cells because of their different sizes.Results: Blood cells greater than 12 μm were guided to a special branch, which i
This paper investigates the robust stability and stabilization analysis of interval fractional-order systems with time-varying delay. The stability problem of such systems is solved first, and then using the proposed results a stabilization theorem is also included, where sufficient conditions are obtained for designing a stabilizing controller with a predetermined order, which can be chosen to be as low as possible. Utilizing efficient lemmas, the stability and stabilization theorems are proposed in the form of LMIs, which is more suitable to check due to various existing efficient convex optimization parsers and solvers. Finally, two numerical examples have shown the effectiveness of our results.
The paper proposes a novel H-∞ load frequency control ( LFC ) design method for multi-area power systems based on an integral-based non-fragile distributed fixed-order dynamic output feedback ( DOF ) tracking-regulator control scheme. To this end, we consider a nonlinear interconnected model for multi-area power systems which also include uncertainties and time-varying communication delays. The design procedure is formulated using semi-definite programming and linear matrix inequality ( LMI ) method. The solution of the proposed LMIs returns necessary parameters for the tracking controllers such that the impact of model uncertainty and load disturbances are minimized. The proposed controllers are capable of receiving all or part of subsys
Stability and stabilization analysis of fractional‐order linear time‐invariant (FO‐LTI) systems with different derivative orders is studied in this paper. First, by using an appropriate linear matrix function, a single‐order equivalent system for the given different‐order system is introduced by which a new stability condition is obtained that is easier to check in practice than the conditions known up to now. Then the stabilization problem of fractional‐order linear systems with different fractional orders via a dynamic output feedback controller with a predetermined order is investigated, utilizing the proposed stability criterion. The proposed stability and stabilization theorems are applicable to FO‐LTI systems with diffe
This paper addresses the problem of robust dynamic output stabilisation of FO-LTI interval systems with the fractional order , in terms of linear matrix inequalities (LMIs). Our purpose is to design a robust dynamic output feedback controller that asymptotically stabilises interval fractional-order linear time-invariant (FO-LTI) systems. Sufficient conditions are obtained for designing a stabilising controller with a predetermined order, which can be chosen to be as low as possible. The LMI-based procedures of designing robust stabilising controllers are preserved in spite of the complexity of assuming the most complete model of linear controller, with direct feedthrough parameter. Finally, some numerical examples with simulations are prese
This paper investigates the robust stabilisation of a class of fractional-order non-linear systems via fixed-order dynamic output feedback controller in terms of linear matrix inequalities (LMIs). The systematic stabilisation algorithm design for low-order controller based on direct Lyapunov approach is proposed. In the presented algorithm the conditions containing the bilinear variables are decoupled into separate conditions without imposing equality constraints or considering an iterative search of the controller parameters. There is no any limiting constraint on the state space matrices and also we assumed the most complete output feedback controller. Simulations results are given to approve the effectiveness and the straightforwardness
The mainspring of this paper is a consensus tracking and a distributed formation in multi-agent systems of fractional order with a leader following strategy. Based on the sliding mode control method, the distributed controller is designed to access consensus and formation in multi-agent systems of fractional order with a leader following strategy. The sliding surfaces is defined as the term of the integral of the fractional error. It has been shown that, if the followering dynamics are affected by disturbances, The sliding mode controller is still valid. In the following, the controller stability is discussed and, finally, several simulations are presented to illustrate the controller's performance.
Conductive nanofibrous scaffolds with that can conduct electrical current have a great potential in neural tissue engineering. The purpose of this study was to survey effects of electrical stimulation and polycaprolactone/polypyrrole/multiwall carbon nanotube (PCL/PPY/MWCNTs) fibrous scaffold on photoreceptor differentiation of trabecular meshwork mesenchymal stem cells (TM‐MSCs). PCL/PPY/MWCNTs scaffold was made by electrospinning method. TM‐MSCs were seeded on PCL/PPY/MWCNTs scaffold and stimulated with a potential of 115 V/m. Scanning electron microscopy, transmission electron microscopy, and FT‐IR were used to evaluate the fabricated scaffold. Immunofluorescence and quantitative real‐time polymerase chain reaction were used t
This paper considers the problem of robust stability and stabilization for linear fractional-order system with nonlinear uncertain parameters, with fractional order 0< a< 2. A dynamic output feedback controller, with predetermined order, for asymptotically stabilizing such uncertain fractional-order systems is designed. The derived stabilization conditions are in LMI form. Simulation results of two numerical examples illustrate that the proposed sufficient theoretical results are applicable and effective for tackling robust stabilization problems. Keywords: Fractional-order system, nonlinear uncertain parameters, linear matrix inequality (LMI), robust stabilization, dynamic output feedback.
An electrical stimulus is a new approach to neural differentiation of stem cells. In this work, the neural differentiation of conjunctiva mesenchymal stem cells (CJMSCs) on a new 3D conductive fibrous scaffold of silk fibroin (SF) and reduced graphene oxide (rGo) were examined. rGo (3.5% w/w) was dispersed in SF‐acid formic solution (10% w/v) and conductive nanofibrous scaffold was fabricated using the electrospinning method. SEM and TEM microscopies were used for fibrous scaffold characterization. CJMSCs were cultured on the scaffold and 2 electrical impulse models (Current 1:115?V/m, 100‐Hz frequency and current 2:115?v/m voltages, 0.1‐Hz frequency) were applied for 7?days. Also, the effect of the fibrous scaffold and electrical im
In this paper, a fixed-order procedure is presented utilizing convex optimization and linear matrix inequalities (LMIs) to control a quarter car uncertain active suspension system. Our purpose is to design a low-order robust controller that keeps the desired design specifications besides the simplicity of the implementation. In our model, the system is influenced by the non-linear disturbance of the road surface, and the polytopic uncertainty model for state matrices of the system is utilized to cover the uncertainties of the model and the delay caused by the dynamic of the system. In this paper, a specific form of a positive definite matrix is used to overcome the complexity of rank minimization constraints. The proposed controller is cons
Conventional model predictive control (MPC) methods are usually implemented to systems with discrete-time dynamics laying on smooth vector space . In contrast, the configuration space of the majority of mechanical systems is not expressed as Euclidean space. Therefore, the MPC method in this paper has developed on a smooth manifold as the configuration space of the attitude control of a 3D pendulum. The Lie Group Variational Integrator (LGVI) equations of motion of the 3D pendulum have been considered as the discrete-time update equations since the LGVI equations preserve the group structure and conserve quantities of motion. The MPC algorithm is applied to the linearized dynamics of the 3D pendulum according to its LGVI equations around th
The main purpose of this paper is to the distributed formation tracking for fractional order multi agent systems with the leader-follower approach. First, it discusses the Lyapunov candidate function used to check the stability of the controlled system. The introduced candidate function is based on the properties of the matrix representing the desired system graph of the system. In this phase, the Lyapunov direct method is used to determine the stability of fractional order systems. Then, using sliding mode control, a decentralized controller design for tracking in fractional multi agent systems is presented in which it introduces and verifies the introduced control inputs. In the model, the input system is also considered as a disturbance
This paper investigates the robust stabilisation of a class of fractional-order non-linear system with positive real uncertainty via fixed-order dynamic output feedback controller in terms of linear matrix inequalities (LMIs). the systematic stabilisation algorithm design for low-order controller based on direct Lyapunov approach is proposed for uncertain fractional-order systems. In the presented algorithm the conditions containing the bilinear variables are decoupled into separate conditions without imposing equality constraints or considering an iterative search of the controller parameters. There is no any limiting constraint on state space matrices and also we assumed the most complete output feedback controller. Simulations results ar
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