Showing 5 results for Rezaei
Mr. Hamed Rezaei, Dr. Mohammad Javad Khosrowjerdi,
Volume 6, Issue 2 (Journal of Control, V.6, N.2 Summer 2012)
Abstract
In this paper, a model-based active fault tolerant control system (FTCs) is proposed forthree phase induction motor (IM) drives subjected to the mechanical faults caused by both stator and rotor failures. FTCsstructure consists of two main parts. The first part is a nominal controller based on feedback linearization for fault-free case to achieve control objectives (rotor flux and speed control). The second part is a sliding mode observer (SMO) in order to estimate additive faults which model mechanical faults in the state space modelof IM. This observer has been used not only for fault reconstruction and productionof additional control inputs for compensating their undesirable influences on performance of IM, but also for online estimation of axial fluxes in any operating conditions. The simulations results are shown to illustrate the effectiveness of the proposed approach to compensate the mechanical faults in IM.
Eng. Farzane Nadi, Dr. Vali Derhami, Dr. Mehdi Rezaeian,
Volume 8, Issue 2 (Journal of Control, V.8, N.2 Summer 2014)
Abstract
Visual servoing system is a system to control a robot by visual feedback so that robot drives from any arbitrary start position to the target positions. Various ways, including control by using model of the robot, designing controller directly, and using Jacobian matrix have been studied. Since there is not access to model of robot and obtaining a model of robot would be difficult and time consuming, in many cases, the control law is obtained using Jacobian matrix. In this paper, inverse of Jacobian matrix is approximated using artificial neural networks. The approximated neural models are used in control law directly. For each degree of freedom of the robot manipulator, a two-layer feedforward neural network is considered. The distance between end-effector and target along the x-axis and y-axis, and the shoulder joint coordinates along the x-axis and y-axis are the inputs of each of the networks and the outputs are the fraction of the related robot joint changes to the image features changes (the elements of the inverse of Jacobian matrix). The proposed method has been implemented on a real robot manipulator. The experimental results show that the proposed control system can move the end-effector to different target positions in workspace with good accuracy.
Soheil Ganjefar, Sara Rezaei, Farzad Hashemzadeh,
Volume 11, Issue 1 (Journal of Control, V.11, N.1 Spring 2017)
Abstract
In this paper, adaptive controller is proposed for bilateral teleoperation systems with parametric uncertainties, asymmetric time-varying delays in their communication channel and sandwich linearity in their actuators. The proposed bounded adaptive approach is a nonlinear-Proportional plus nonlinear Damping (nP+nD) controller which nonlinear adaptive terms are also employed locally to cope with the parametric uncertainties. The designed controller has the ability to deal with parameter variations in the dynamics of the master and slave robots . The proposed controller also guarantees asymptotic stability and position tracking and avoiding the inputs to reach their usual actuator bounds. The asymptotic stability and tracking performance of the teleoperation system are proved using a Lyapunov-Krasovskii functional. The effectiveness of the proposed method is corroborated through simulation results.
Mahdi Rezaei Bahrmand, Hamid Khaloozadeh, Parastoo Reihani Ardabili,
Volume 14, Issue 5 (Journal of Control, Vol. 14, No. 5, Special Issue on COVID-19 2021)
Abstract
In this paper, a model is proposed based on the different levels of social restrictions for the COVID-19 spread restraint in Iran. Also, a Genetic Algorithm (GA) identifies parameters of model using reported main data from the Iranian Ministry of Health and simulated data based on proposed model. Whereas Model Predictive Control (MPC) is a popular method which has been widely used in process control, after the discretization of model by a common method like Euler method, then we can consider the appropriate constraints and solve online optimization problem. In this paper, we have shown that the MPC controller able to flatten infected (symptomatic) individual curve and decrease its peak by applying the different levels of social restrictions. Numerical example and simulation results, based on main data, are given to illustrate the capability of this method.
Dr. Fatemeh Rezaei, Parya Rashidy,
Volume 17, Issue 4 (Journal of Control, V.17, N.4 Winter 2024)
Abstract
Despite the expansion of the smart grid, information security in this network has faced many challenges, and we need a strong security framework for it. In this article, a compound and efficient method for authentication in the network of smart meters is presented. In the proposed model, first, the authentication of devices and sensor data is done in the smart meter, and then the value of the cumulative hash chain of the authorized devices' data is calculated in the smart meter and along with the cumulative data is sent to the collector. In the first step of the proposed method, devices are connected to the smart meter using RFID tags, and the device ID is processed in the smart meter. We use the Elliptic Curve method for authentication. In the second step, by calculating the value of the cumulative hash chain and comparing it with the received value, the validation of the received messages is done on the collector. Therefore, sending additional data to the collector, occupying the bandwidth, and the possibility of intrusion of malicious devices are prevented. The proposed method, in addition to adapting to the structure of the smart grid, also provides a lower computational and communication cost than the existing methods.
