per
Iranian Society of Instrumentation and Control Engineers
Journal of Control
2008-8345
2538-3752
2016-03
9
4
1
25
article
Proposing Interval Activation Functions in Radial Basis Function Neural Network to Predict Nonlinear dynamic systems
Allahyar Zohoori Zangeneh
z.zangeneh@gmail.com
1
Mohammad Teshnehlab
teshnehlab@eetd.kntu.ac.ir
2
Mojtaba Ahmadieh Khanesar
ahmadieh@semnan.ac.ir
3
PHD Student, Department of Computer, Artificial Intelligence branch, Engineering Facultu, Computer Group, Sciences & Research Branch, Islamic Azad University
Electrical Engineering Faculty, Control Engineering Group, K.N.Toosi University of Technology (K.N.Toosi)
Electrical & Computer Engineering Faculty, Power & Control Group, Semnan University
Abstract: A Radial Basis Function Neural Network (RBFNN) is a general approximator. In this paper a granular activation function is proposed to improve its learning under the noisy conditions. The granular activation function is also named the interval activation function and it is typicaly the Gaussian function which benefits from having a fixed mean and an uncertain standard deviation. The hidden layer of the proposed network has a total of three parameters to train that it consists the means, the lower bounds of the standard deviations and the higher bounds of the standard deviations of the Gaussian functions. The output layer parameters for training are the means of the interval weights and the intervals of the weights. “K-Means clustering algorithm” method is used to train these parameters. The purpose of the above learning method is regarded as one of the granular method presenting the bottom-up granulation which causes the input vectors clustered in the larger granules in the hidden layer. Gradient descend method is also used to train these parameters to compare with this novel method. The structure is tested with or without noisy data to identify a nonlinear dynamic system with multiple time delays and to predict a chaotic model, Mackey-Glass. It has been shown that the sensibility related to input alterations reduces because of using the granular activation function in RBF Neural Network structure and the response of Granular RBF Neural Network with noisy data is better than RBF Neural Network.
http://joc.kntu.ac.ir/article-1-97-en.pdf
Granular Radial Basis Function Neural Network (GRBFNN)
Granular activation function
Noisy data
Interval standard deviation
Nonlinear dynamic systems and Chaotic Models.
per
Iranian Society of Instrumentation and Control Engineers
Journal of Control
2008-8345
2538-3752
2016-03
9
4
27
39
article
Global Finite Time Tracking for a General Class of Nonlinear Systems Using Nonsingular Adaptive-Terminal Sliding Mode Control
Ali Abooee
aliaboee@yahoo.com
1
Masoud Moravej Khorasani
m.moravej.kh@gmail.com
2
Mohammad Haeri
haeri@sina.sharif.edu
3
Sharif Univ. of Tech.
In this paper, the global finite time tracking problem of desired trajectories for a wide group of nonlinear systems subjected to unbounded disturbances and uncertainties is addressed. The considered class for nonlinear systems, containing a chain of interacting double integrator subsystems, can describe and model variety of practical systems. To tackle the mentioned problem, the adaptive control approach is incorporated with a nonsingular terminal sliding mode control and a new control method is suggested. Finite time adaptation laws are designed to estimate unknown constant coefficients of upper bound of uncertainties and disturbances within a finite time. Analytical studies demonstrate that by applying the proposed control scheme, tracking errors will converge to zero exactly after a tunable finite time. Also, a relation is presented for calculating an upper bound for the mentioned time which depends on initial conditions of the states and some arbitrary parameters. The convergence rate of the tracking errors could be tuned by proper choice of these parameters. Finally, analytical results are simulated on two practical systems including thrust active magnetic bearing (TAMB) and two-link robot manipulator to demonstrate the effectiveness of the suggested control technique.
http://joc.kntu.ac.ir/article-1-319-en.pdf
Global finite time stability
Finite time tracking
Nonsingular adaptive-terminal sliding mode control
Finite settling and reaching time
per
Iranian Society of Instrumentation and Control Engineers
Journal of Control
2008-8345
2538-3752
2016-03
9
4
41
53
article
Fuzzy Electronic Stability Control System for Electric Vehicle with Four Motor in Wheel
Javad Sharifi
sharifi@qut.ac.ir
1
Alireza Amirjamshidi
alirezaamirjamshidy@gmail.com
2
Qom University of Technology
Qom University of Technology
In this paper, a control system for stability improvement and electrical car steering in hard driving situation is developed. At first, a sliding control system by using of fuzzy logic is designed for car prevention from wheel sliding in the situation of driver extreme brake or acceleration. Then, for car stability preservation in un-stabilizer maneuver, a fuzzy electronic stabilizer controller is designed. Finally, to invest the system operation for stability preservation, several car maneuver driving is simulated. The simulation results shows that the control rule and designed fuzzy controller, noteworthy can keep the car stability and maneuverability.
http://joc.kntu.ac.ir/article-1-299-en.pdf
Sliding Control
Electronic Stability
Fuzzy Controller.
per
Iranian Society of Instrumentation and Control Engineers
Journal of Control
2008-8345
2538-3752
2016-03
9
4
55
66
article
Duty Cycles Control in Three-phase Multilevel Converters for Switching Loss Reduction
Mohammad Jafar Mojibian
mojibian@ee.kntu.ac.ir
1
Mohammad Tavakoli Bina
tavakoli@eetd.kntu.ac.ir
2
There are various modulation techniques for different topologies of multilevel converters that every technique has its own advantages as well as disadvantages in practice. This paper develops a new efficient modulating technique for three-phase differential multilevel converters that is based on using the concept of offset optimization and duty cycles control in a simple buck converter. The proposed modulation technique with achievement to full DC utilization reduces switching losses. To evaluate the suggested method, the modulation technique with three other conventional methods are implemented on an asymmetric 16–level converter. Comparative analysis for the experiments confirms that applying the presented technique on multilevel converter leads lower switching losses, better THD as well as optimal usage of the DC-link.
http://joc.kntu.ac.ir/article-1-352-en.pdf
multilevel converter
reduced structures
duty cycles control
fix offset modulation
harmonic injection.
per
Iranian Society of Instrumentation and Control Engineers
Journal of Control
2008-8345
2538-3752
2016-03
9
4
67
76
article
Effect of Active and Passive Filters on Induced Shaft Voltage on Synchronous Generators Using Controller: A comparative Study
Mahmoud Samiei-Moghaddam
samiei352@yahoo.com
1
Shokrollah shokri-kojori
shokri@eetd.kntu.ac.ir
2
In this paper, we investigate the reduction of shaft induced voltage using both active and passive filters. An RLC circuit for passive filter and a DC-DC buck converter for active filter is used which can remove the high-frequency spikes leading to the reduction in induced shaft voltage. Buck converter has a minimum-phase behavior and therefore is preferred to any other converters. A static excitation system using 6-pulse thyristor rectifier is employed for 5 kW synchronous generators. Active and passive filters are placed between rectifier and excitation winding of the synchronous generator. As simulation and experimental results show, both filters are capable to remove the parasitic capacitance efficaciously and so induced shaft voltage is mitigated significantly. However, in contrast to the passive filter, active filter shows the better performance to reducing the shaft induced voltage. This reduction can increase the life time of generator's bearing.
http://joc.kntu.ac.ir/article-1-310-en.pdf
Active filter
Induced shaft voltage
Passive filter
Static excitation system.
per
Iranian Society of Instrumentation and Control Engineers
Journal of Control
2008-8345
2538-3752
2016-03
9
4
77
85
article
Stability Analysis of Discrete-time Switched Linear Systems in the presence of Time-delay and Parametric Uncertainties
Nasrollah Azam Baleghi
n.baleghi@sutech.ac.ir
1
Mohammad hossein shafiei
shafiei@sutech.ac.ir
2
Shiraz university of technology
Shiraz university of technology
This paper studies the stability conditions of discrete-time switched linear systems in the presence of parametric uncertainties and time-delay. The time-varying delay is assumed to be unknown but bounded. Based on the discrete Lyapunov functional, sufficient conditions are investigated to determine the upper bound of admissible time-delay. Furthermore, the average dwell time method that is an effective tool for stability analysis of switched systems is used to derive the exponential stability conditions. These conditions characterize the switching signal that does not depend on any uncertainties. Finally, numerical example is provided to verify the theoretical results.
http://joc.kntu.ac.ir/article-1-318-en.pdf
Discrete-time switched linear systems
Stability Analysis
Parametric Uncertainty and Time-delay