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Modeling, Study of Operational Characteristics and Fabrication of an Ultrasonic Linear Motor
, Ph.D. Dissertation Sharif University of Technology ; Akbari, Javad (Supervisor)
Abstract
Nowadays, piezoelectric motors are used as one of the suitable options in the modern motion control field and precise positioning systems due to their suitable functional characteristics such as high power to weight ratio, fast dynamic response, direct drive motion, integrated structure without backlash and possibility of miniature design. Accordingly, the present dissertation is defined in order to develop a comprehensive path for modeling, analysis and optimization of the ultrasonic piezoelectric motors. In this study, the focus is on the ultrasonic motors with an elliptical structure, but the results can be used for other structures as well. In the present work, the process of modeling of...
Using axiomatic design theory for selection of the optimum design solution and manufacturing process plans of a limited angle torque motor
, Article Journal of Manufacturing Science and Engineering, Transactions of the ASME ; Vol. 136, Issue. 5 , 2014 ; ISSN:1096-6668 ; Houshmand, M ; Nasiri-Zarandi, R ; Mirsalim, M ; Sharif University of Technology
Abstract
The brushless dc limited angle torque motor (LATM) has been widely used in areas of aerospace equipments, robot drives, optical scanning systems and any drive systems that require limited motion, ranging from the simple ON-OFF servo valves to the accurate tracking of a reference signal. This paper presents the optimum design procedure of a brushless direct current LATM to satisfy the functional requirements (FRs) and constraints using Independence axiom in axiomatic design (AD) approach. Also, to select the best manufacturing process plan, we consider both cost and thermal performance as two effective criteria, and evaluate available alternatives by computing information content in...
An analytical and experimental study of a hybrid rocket motor
, Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; Vol. 228, Issue. 13 , December , 2014 , pp. 2475-2486 ; ISSN: 09544100 ; Soltani, M. R ; Sharif University of Technology
Abstract
The hybrid rocket motor is a kind of chemical propulsion system that has been recently given serious attention by various industries and research centers. The relative simplicity, safety and low cost of this motor, in comparison with other chemical propulsion motors, are the most important reasons for such interest. Moreover, throttle-ability and thrust variability on demand are additional advantages of this type of motor. In this paper, the result of an internal ballistic simulation of hybrid rocket motor in a zero-dimensional form is presented. Further to validate the code, an experimental setup was designed and manufactured. The simulation results are compared with the experimental data...
Continuum model of actin-myosin flow
, Article 2013 20th Iranian Conference on Biomedical Engineering, ICBME 2013 ; December , 2013 , Pages 98-102 ; Firoozabadi, B ; Saidi, M. S ; Sharif University of Technology
IEEE Computer Society
2013
Abstract
The front part of a cell is divided to two regions called lamellum and lamellipodium (lamellipodial). This part plays an essential role for cell migration. Indeed, there are many protein filaments called actin in lamellum and lamellipodium, which induce the cell motion with polymerization in the leading edge of the cell. The actin filaments adhere to the extracellular matrix (ECM) by means of focal adhesions and they have contact by myosin motor proteins. The myosin motor proteins cause actin retrograde and anterograde flow exerted contractile stress on them. The focal adhesions exert frictional stress on the actin filaments. In this work, we developed a two-dimensional continuum model of...
A new definition for total harmonic distortion in inverter-fed induction motors including loss considerations
, Article 42nd International Conference on Large High Voltage Electric Systems 2008, CIGRE 2008, Paris, 24 August 2008 through 29 August 2008 ; 2008 ; Kaboli, S ; Oraee, H ; Sharif University of Technology
2008
Abstract
Harmonic information is necessary tools in the estimation of motors life and performance. The conventional expression of harmonic amount is carried out by total Harmonic distortion. This distortion factor is only related to amplitude of harmonics while the motor loss is affected by frequency domain of them. In this paper a new definition of this factor has been presented. This definition includes the frequency of harmonics as well as their amplitudes. Experimental results verify the validity of this new definition
On the performance of optimal flux search controller for DTC based induction motor drives
, Article 2005 IEEE International Conference on Electric Machines and Drives, San Antonio, TX, 15 May 2005 through 15 May 2005 ; 2005 , Pages 1752-1756 ; 0780389875 (ISBN); 9780780389878 (ISBN) ; Vahdati Khajeh, E ; Zolghadri, M. R ; Homaifar, A ; Sharif University of Technology
IEEE Computer Society
2005
Abstract
Application of a flux search controller in direct torque control of induction motor drives produces divergence problem and steady state flux ripple, because of the disturbance in the control loop. In this paper, an investigation about the origin of this noise has been performed. It is shown that the variation of voltage harmonics is the main reason of disturbance in the flux control loop. The minimum allowable value of flux step has been determined based on this analysis to prevent the divergence problem. Feasibility of noise cancellation has been discussed. Experimental results are presented to justify the theoretical analysis. © 2005 IEEE
A fast optimal flux search controller with improved steady state behavior for DTC based induction motor drives
, Article 2005 IEEE International Conference on Electric Machines and Drives, San Antonio, TX, 15 May 2005 through 15 May 2005 ; 2005 , Pages 1732-1736 ; 0780389875 (ISBN); 9780780389878 (ISBN) ; Vahdati Khajeh, E ; Zolghadri, M. R ; Homaifar, A ; Sharif University of Technology
IEEE Computer Society
2005
Abstract
Flux search controllers are proposed to improve the efficiency of electrical motors especially induction motors. In this paper, a flux search controller is proposed to increase the efficiency of a direct torque controlled induction motor with light load. The reference flux value is determined through a two stage minimization algorithm with the amplitude of the stator current as the objective function. In the transient state, a great flux step is used to speed up the convergence. In the steady state, a noise cancellation algorithm is used to let using small flux step and improves the steady state behavior of flux controller. Simulation and experimental confirm the fast dynamics of the...
An extended and improved discrete space vector modulation direct torque control for induction motors
, Article 2004 IEEE 35th Annual Power Electronics Specialists Conference, PESC04, Aachen, 20 June 2004 through 25 June 2004 ; Volume 5 , 2004 , Pages 3414-3420 ; 02759306 (ISSN); 0780383990 (ISBN) ; Zolghadri, M. R ; Homaifar, A ; Sharif University of Technology
2004
Abstract
In the classical DTC scheme, due to the limited number of the VSI voltage vectors, large and small errors can not be distinguished. In fact, the switching vectors chosen for large errors are the same as those chosen for small errors. In this paper, in order to overcome this problem, after considering the primary ideas of the DSVM-DTC technique, a new approach for the realization of the DSVM-DTC methodology of the induction machine is proposed. The proposed method, along with its simplicity, has an improved performance in terms of the torque and the current ripple and can be easily extended. In addition, it minimizes the steady state torque error. By using the proposed DSVM-DTC methodology,...
Brain-Computer Interface for Navigating in Virtual Environments
, M.Sc. Thesis Sharif University of Technology ; Shamsollahi, Mohammad Bagher (Supervisor)
Abstract
The aim of this project is designing and implementation of a BCI for interacting with virtual environments. BCI is an interface between brain and computer that connect those by translating brain signals into understandable instruction for computer. There are different ways to generate brain states for classification in BCI technology. One of those, is based on motor imagery (MI). In this project, we used motor imagery of left hand, right hand and foot. subject training in this kind of BCI (MI-based BCI) is very vital. in order to speed up subject training period and consequently enhance the separability of brain states, computer graphics and virtual environments are used to excite the...
The effect of chronic low back pain on trunk accuracy in a multidirectional isometric tracking task
, Article Spine ; Vol. 39, Issue. 26 , 2014 , pp. E1608-E1615 ; ISSN: 1362-2436 ; Mousavi, S. J ; Sedaghatnejad, E ; Talebian, S ; Parnianpour, M ; Sharif University of Technology
Abstract
Study Design. A cross-sectional study to quantify trunk motor control during multidirectional isometric tracking tasks.Objective. To investigate the effect of chronic low back pain (LBP) on trunk neuromuscular performance while participants performed isometric exertions of trunk muscles to track targets in different angles with various magnitudes.Summary of Background Data. Tracking tasks especially in multidirectional activities are among the common research methods to quantify human motor control in different conditions. However, little information is available on trunk motor control during these tasks. There is no study investigating trunk accuracy during multidirectional isometric...
Flux search control of field oriented control of six-phase induction motor supplied by SVPWM
, Article Przeglad Elektrotechniczny ; Volume 87, Issue 8 , 2011 , Pages 171-175 ; 00332097 (ISSN) ; Rahmati, A ; Kaboli, S ; Sharif University of Technology
2011
Abstract
This paper deals with the efficiency optimization of Field Oriented Control (FOC) of a six-phase induction motor supplied by Space Vector PWM (SVPWM) using the flux Search Controller (SC) technique. The proposed technique is based on controlling flux to achieve maximum efficiency at light load or low speed. Flux search controller technique is not only cost effective and easy to implement but also robust against parameter variations. Flux control algorithm in six-phase induction machine speed controller reduces 6n±1 harmonic loss as well as other losses like that of copper and core. Simulation results are carried out and they verify the effectiveness of the proposed approach
Two-phase acto-cytosolic fluid flow in a moving keratocyte: a 2d continuum model
, Article Bulletin of Mathematical Biology ; Volume 77, Issue 9 , September , 2015 , Pages 1813-1832 ; 00928240 (ISSN) ; Firoozabadi, B ; Saidi, M. S ; Sharif University of Technology
Springer New York LLC
2015
Abstract
The F-actin network and cytosol in the lamellipodia of crawling cells flow in a centripetal pattern and spout-like form, respectively. We have numerically studied this two-phase flow in the realistic geometry of a moving keratocyte. Cytosol has been treated as a low viscosity Newtonian fluid flowing through the high viscosity porous medium of F-actin network. Other involved phenomena including myosin activity, adhesion friction, and interphase interaction are also discussed to provide an overall view of this problem. Adopting a two-phase coupled model by myosin concentration, we have found new accurate perspectives of acto-cytosolic flow and pressure fields, myosin distribution, as well as...
Electromagnetic design optimization of a modular linear flux-reversal motor
, Article Electric Power Components and Systems ; Volume 44, Issue 18 , 2016 , Pages 2112-2120 ; 15325008 (ISSN) ; Tootoonchian, F ; Sharif University of Technology
Taylor and Francis Inc
Abstract
Although modular linear flux-reversal permanent magnet motors are widely attractive for high reliability urban rail transit because of their advantages such as high power density, high reliability, low permanent magnet flux leakage problem, and improved fault-tolerant capability, they suffer from high thrust ripples. In this article the authors use a layer model for defining different optimization problems to improve thrust density, efficiency, and thrust ripples, independently and simultaneously. Design variables are chosen based on the sensitivity analysis of different objective functions relative to motor different geometrical parameters and some constraints are taken into account to...
Design and manufacturing of ultrasonic motor with in-plane and out-of-plane bending vibration modes of rectangular plate with large contact area
, Article Measurement: Journal of the International Measurement Confederation ; Volume 109 , 2017 , Pages 425-431 ; 02632241 (ISSN) ; Sarhan, A. A. D ; Akbari, J ; Mardi, N. A ; Sharif University of Technology
Abstract
Ultrasonic motor working with coupled in-plane and out-of-plane vibration modes of rectangular plate is proposed and experimentally investigated. Thanks to its unique configuration, proposed motor provides large contact area between stator and rotor of motor which can reduce wear and enhance motor life-time. The proposed motor is designed using finite element method and according to the design, a prototype is fabricated and its working characteristics such as speed, normal and driving force and working frequency are measured. Overall dimension of designed prototype is 49 × 14 × 2 mm, working frequency of motor is 49.6 kHz, no-load speed and stall force of motor are 122 rpm and 0.32 mN m at...
Analysis of six-phase induction motor with distributed and concentrated windings by using the winding function method
, Article 23rd International Conference on Electrical Machines, ICEM 2018, 3 September 2018 through 6 September 2018 ; 2018 , Pages 2423-2429 ; 9781538624777 (ISBN) ; Vaschetto, S ; Tahami, F ; Capolino, G. A ; Henao, H ; Nasiri Gheidari, Z ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Multi-phase induction motors feature a high fault-tolerance capability that makes them suitable for safety critical applications. On the other hand, concentrated winding is more fault-tolerant than conventional distributed winding. Therefore, the general idea is to use concentrated winding on the six-phase induction motor to gain more fault-tolerance capacity. Using concentrated winding has several advantages over distributed one, but it has the disadvantage of higher distortion of air gap flux density, which affects the motor performance significantly. In this paper, some concentrated windings are studied analytically by using the winding function analysis, and the layout with better...
Performance evaluation of custom power devices in process of motor bus transfer
, Article 2009 4th IEEE Conference on Industrial Electronics and Applications, ICIEA 2009, Xi'an, 25 May 2009 through 27 May 2009 ; 2009 , Pages 2279-2284 ; 9781424428007 (ISBN) ; Abedi, M ; Darabi, F ; Sharif University of Technology
2009
Abstract
Quality and continuity of electrical power to sensitive loads especially in power plants and industrial sectors is of great importance. For this reason, bus transfer is used. During the bus transfer interval, sensitive loads especially motors will be interrupted, and may encounter difficulties. So, it is used reactive power compensator and custom power devices to mitigate stress in motors and improve power quality indices. This paper presents the effect of reactive power compensator and custom power devices paralleling with motor in process of bus transfer which is done in two methods: EMTS and STS. Also, it is investigated dynamic performance of induction motor and spin-down curves in...
A novel fault tolerant reconfigurable concept for vector control of induction motors
, Article EPE-PEMC 2006: 12th International Power Electronics and Motion Control Conference, Portoroz, 30 August 2006 through 1 September 2006 ; 2007 , Pages 1199-1204 ; 1424401216 (ISBN); 9781424401215 (ISBN) ; Shojaei, A ; Sharif University of Technology
2007
Abstract
AC drive users with sophisticated applications are demanding greater reliability to avoid process interruptions. AC motor drive systems are susceptible to sensors failure. A novel fault tolerant Field Oriented Control system for induction motors is introduced. The system maintains speed control in the event of sensors malfunction and adverse signal conditions, providing enhanced reliability. Different motor models are combined by a Fuzzy aggregation system in order to give a reliable estimate of flux vector. The proposed control system is an effective and easy to implement method giving a potential for motor drive reliability enhancement. © 2006 IEEE
A fast flux search controller for DTC-based induction motor drives
, Article IEEE Transactions on Industrial Electronics ; Volume 54, Issue 5 , 2007 , Pages 2407-2416 ; 02780046 (ISSN) ; Zolghadri, M. R ; Vahdati Khajeh, E ; Sharif University of Technology
2007
Abstract
In this paper, a flux search controller is proposed to increase the efficiency of a direct torque-controlled induction motor in full load range. The value of the flux reference is determined through a minimization algorithm. The amplitude of stator current is used as the objective function since it is shown that samples of the stator current have better statistical properties than input power. In addition, the stator current has more sensitivity to the flux variation than input power. These two properties allow implementing an adaptive algorithm to determine the proper flux step without waste of time. The minimum allowable value of the flux step has been determined based on this process to...
A comprehensive evaluation of spine kinematics, kinetics, and trunk muscle activities during fatigue-induced repetitive lifting
, Article Human Factors ; 2021 ; 00187208 (ISSN) ; Mazloumi, A ; Arjmand, N ; Keihani, A ; Karimi, Z ; Ghasemi, M. S ; Kordi, R ; Sharif University of Technology
SAGE Publications Inc
2021
Abstract
Objective: Spine kinematics, kinetics, and trunk muscle activities were evaluated during different stages of a fatigue-induced symmetric lifting task over time. Background: Due to neuromuscular adaptations, postural behaviors of workers during lifting tasks are affected by fatigue. Comprehensive aspects of these adaptations remain to be investigated. Method: Eighteen volunteers repeatedly lifted a box until perceived exhaustion. Body center of mass (CoM), trunk and box kinematics, and feet center of pressure (CoP) were estimated by a motion capture system and force-plate. Electromyographic (EMG) signals of trunk/abdominal muscles were assessed using linear and nonlinear approaches. The L5-S1...