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actuators
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Surface acoustic waves as control actuator for drop removal from solid surface
, Article Fluid Dynamics Research ; Volume 53, Issue 4 , 2021 ; 01695983 (ISSN) ; Taleghani, A. S ; Rahni, M. T ; Sharif University of Technology
IOP Publishing Ltd
2021
Abstract
Several types of research are performed on flow control and this fact highlights the importance of this topic. Over the last two decades, actuators based on acoustic waves have attracted much attention and have been used in widespread applications from mixing to pumping. This paper reveals the effects of some control parameters such as wave amplitude and wave frequency on the dynamical behavior of a sessile drop in order to change the flow characteristics. For this purpose, the removal of water from surfaces and drop movement against gravity are considered. Flow dynamics is simulated using lattice Boltzmann method. The results show that the drop can be removed from the surface in a short...
Adaptive and Robust Control of Robots Including Actuator Dynamics
, M.Sc. Thesis Sharif University of Technology ; Namvar, Mehrzad (Supervisor)
Abstract
Ignoring actuator dynamics in control of rigid manipulators can in practice result in performance degradation or loss of system stability. However, on the other hand, consideration of actuator dynamics usually requires measurement of robot joint torques that is not cost-effective. This thesis addresses motion tracking control of an n-DOF rigid robot by taking into account its actuator dynamics. Joint torque measurement is avoided by using an adaptive observer. The novelty of this thesis is in developing a controller for robot manipulators including non-negligible actuator dynamics in presence of uncertainty in robot dynamics; without using joint torque measurement. Controller design is done...
Adaptive Compensation of Effect of Slow Dynamic Actuators in Robots Without Output Torque Measurement
, M.Sc. Thesis Sharif University of Technology ; Namvar, Mehrzad (Supervisor)
Abstract
A motion tracking control design of an n-DOF rigid robot by taking into account its actuator dynamics is proposed in this paper using backstepping technique. neglecting actuator dynamics in control of rigid robot manipulators can degrade the performance and loss of stability. However,consideration of actuator dynamics entails joint torque or armature currents measurement. In this study, torque measurement has been avoided using an torque estimator.. Finally, Semi-global convergence for motion tracking error are proven. In addition, A simulation example of a two-link robotic manipulator is also given to clarify the effectiveness of proposed design method. Considering actuator dynamics entails...
Design and Manufacturing Electromagnetic Actuator for Removal Brain Shunt Ventricular Catheter Obstruction
, M.Sc. Thesis Sharif University of Technology ; Akbari, Javad (Supervisor)
Abstract
Hydrocephalus is a desease which causes by unnatural accumulation of cerebrospinal fluid in the brain ventricles. One of the most convenient ways to treat hydrocephalus disease is to use a brain shunt which consists of ventricular catheter, valve and distal catheter. Ventricular catheter obstruction is the main reason for shunt replacement in the human brain. This project attempts to remove obstruction of the ventricular catheter by mechanical forces. For this purpose, a magnet and a variable magnetic field suggested to apply mechanical force on a brush sliding on the shunt. On the inner surface of the ring-shaped magnet, brushes have been embedded and the magnet is placed on the outer...
Design and Fabrication of a Ferrofluidic Miniature Pump
, Ph.D. Dissertation Sharif University of Technology ; Shafii, Mohammad Behshad (Supervisor) ; Moosavi, Ali (Supervisor)
Abstract
This thesis presents the prototype design and fabrication of magnetically actuated miniature pumps which utilize self-sealing capability of ferrofluid-covered permanent magnets in both pumping and valving mechanisms. The contactless external actuation feature of the design enables integration of the pump with other PMMA-based microfluidic systems with low cost and disposability. The body of the 1st fabricated prototype pump consists of three nozzle/diffuser elements and two pumping chambers connected to the ends of a flat-wall pumping cylinder. A cylindrical permanent magnet placed inside the pumping cylinder acts as a piston which reciprocates by using an external magnetic actuator driven...
An IPMC-made deformable-ring-like robot
, Article Smart Materials and Structures ; Volume 21, Issue 6 , June , 2012 ; 09641726 (ISSN) ; Ozmaeian, M ; Alasty, A ; Iraji Zad, A ; Sharif University of Technology
Abstract
In this paper application of ionic polymermetal composite (IPMC) as an actuator in a deformable circular robot is studied. Large bending deformation induced by small stimulating voltage, low stiffness and the sensing characteristics that in future work can be used in feedback control make IPMC a good choice for such an application. Here, first a model for IPMC is proposed that can be used in simulating different arrangements of actuators. The parameters of the model are determined using results of blocked force and free displacement tests. Using this model, potentials of an IPMC-made ring-like robot in passing obstacles and the effect of the number of segments on the rings performance are...
Control of vibration suppression of a smart beam by pizoelectric elements
, Article 2nd International Conference on Environmental and Computer Science, ICECS 2009, 28 December 2009 through 30 December 2009, Dubai ; 2009 , Pages 165-169 ; 9780769539379 (ISBN) ; Durali, L ; Rad, F. P ; Zareie, S ; Sharif University of Technology
Abstract
Vibration control is an essential problem in different structure. Smart material can make a structure smart, adaptive and self-controlling so they are effective in active vibration control. Piezoelectric elements can be used as sensors and actuators in flexible structures for sensing and actuating purposes. In this paper we use PZT elements as sensors and actuator to control the vibration of a cantilever beam. Also we study the effect of different types of controller on vibration. © 2009 IEEE
Study of a piezo-electric actuated vibratory micro-robot in stick-slip mode and investigating the design parameters
, Article Nonlinear Dynamics ; Volume 89, Issue 3 , 2017 , Pages 1927-1948 ; 0924090X (ISSN) ; Salarieh, H ; Vossoughi, G ; Sharif University of Technology
Springer Netherlands
2017
Abstract
In this paper, the stick-slip motion of a new type of micro-robot with two perpendicular vibratory actuators is studied which is based on the friction drive principle. The actuators are based on piezo-electric phenomenon which are driven by a harmonic voltage, and both of them are mounted on the micro-robot body. These actuators cause the micro-robot moves forward or backward due to the specified phase difference between the voltages applied to vertical and horizontal actuators. Since the dynamics of the actuators affects on the micro-robot motion, so to derive the equations of motion the coupled dynamics between the body of robot and vibratory masses of actuators are considered, and the...
Smart micro/nano-robotic systems for gene delivery
, Article Current Gene Therapy ; Volume 17, Issue 2 , 2017 , Pages 73-79 ; 15665232 (ISSN) ; Nejat Pishkenari, H ; Sharif University of Technology
Bentham Science Publishers B.V
2017
Abstract
Background: Small scale robotics have attracted growing attention for the prospect of targeting and accessing cell-sized sites, necessary for high precision biomedical applications and drug/gene delivery. The loss of controlled gene therapy, inducing systemic side effects and reduced therapeutic efficiency, can be settled utilizing these intelligent carriers. Methods: Newly proposed solutions for the main challenges of control, power supplying, gene release and final carrier extraction/degradation have shifted these smart miniature robots to the point of being employed for practical applications of transferring oligonucleotides (pDNA, siRNA, mRNA, etc.) in near future. Conclusion: In this...
Design of a robotic cameraman with three actuators for laparoscopic surgery
, Article Proceedings of Frontiers in Biomedical Devices Conference, NanoBio06, Irvine, CA, 8 June 2006 through 9 June 2006 ; Volume 2006 , 2006 ; Farahmand, F ; Meghdari, A ; Sayyaadi, H ; Savoj, L ; Mirbagheri, E ; Sharif University of Technology
American Society of Mechanical Engineers
2006
Minimizing the Error of Set Point Tracking in MIMO Plants with Broken Actuators
, M.Sc. Thesis Sharif University of Technology ; Haeri, Mohammad (Supervisor)
Abstract
Fault occurrence is an inevitable problem in industrial plants. These faults have numerous types. Some common kinds of faults are faults in actuators, faults in system dynamics, and faults in sensors. In many cases it is not possible to change or repair the broken part immediately. On the other hand, it is not reasonable to shut-down the whole system due to a minor failure. Therefore we should take a measure to have the best output possible in a faulty plant. In this thesis we have proposed a new static compensator by which we distribute the contribution of the faulty actuator among the other ones. At the end we evaluate the method by means of simulations
Design and Fabrication of a Control Setup for a Miniature Mobile Robot Excited by Magnetic Field
, M.Sc. Thesis Sharif University of Technology ; Zohoor, Hassan (Supervisor) ; Nejat Pishkenari, Hossein (Co-Supervisor)
Abstract
Humans can take lots of advantages from influencing on small particles. Since manipulation of micro sizes by humans or macro robots, due to their precession and size, is not possible, a new field of study, called Microrobotics, has been introduced. To better understand the working principles in small dimensions, we first need to know the governing physics laws. This step helps us to identify the dominant forces in the small dimensions, which, in turn, leads to better actuation of miniature robots. Because of the size of the miniature robots, one of the best actuation methods is the interaction of the magnetic field on magnetic dipoles. To use the magnetic field as an actuation force, the...
Aerodynamic Performance Improvement of Megawatt Wind Turbine Rotor Using Plasma Actuator
, M.Sc. Thesis Sharif University of Technology ; Ebrahimi, Abbas (Supervisor)
Abstract
For validation of simulation, plasma actuator was modelled on a flat plate in quiescent flow, which is result in low-speed jet near the wall. The results were compared with similar model and were showed good agreement with them. After that, blade was modelled in three-dimensional manner with MRF technique and periodic method and the results were validated in clean situation (absence of plasma). In the following, turbine was analysed with a code, which was written in MATLAB software based on BEM method and the results were compared with present CFD simulation. Then, plasma actuator was used in chordwise in parts of the blade to improve wind turbine performance. Also it was used in spanwise...
Design of a Robust Active Controller to Suppress the Undesirable Vibration of Power Transmission Lines by Using the Intermediate Actuators and Optimization of Their Locations
, M.Sc. Thesis Sharif University of Technology ; Moradi, Hamed (Supervisor)
Abstract
Power transmission lines, which are responsible for the distribution and transmission of electrical energy from the power plant to the consumer areas, due to their characteristics such as long length and flexibility with low structural damping, face environmental irritations, especially the galloping phenomenon, causing many damages annually. In this study, it has been attempted to reduce the vibrations of power transmission lines by designing a robust active control and by using intermediate actuators in such a way that the failures of these lines can be prevented. For this purpose, linear modeling of the system and designing the controller using the pole replacement method have been done....
Fluid-solid interaction in electrostatically actuated carbon nanotubes
, Article Journal of Mechanical Science and Technology ; Vol. 28, issue. 4 , 2014 , p. 1431-1439 ; Rastgoo, A ; Ahmadian, M. T ; Sharif University of Technology
Abstract
This paper deals with investigation of fluid flow on static and dynamic behaviors of carbon nanotubes under electrostatic actuation. The effects of various fluid parameters including fluid viscosity, velocity, pressure and mass ratio on the deflection and pull-in behaviors of the cantilever and doubly clamped carbon nanotubes are studied. Furthermore, the effects of temperature variation on the static and dynamic pull-in voltages of the doubly clamped carbon nanotubes are reported. The results reveal that altering the fluid parameters significantly changes the mechanical and pull-in behaviors. Hence, the proposed system can be applied properly as a nano fluidic sensor to sense the various...
Size-dependent characteristics of electrostatically actuated fluid-conveying carbon nanotubes based on modified couple stress theory
, Article Beilstein Journal of Nanotechnology ; Volume 4, Issue 1 , 2013 , Pages 771-780 ; 21904286 (ISSN) ; Rastgoo, A ; Ahmadian, M. T ; Sharif University of Technology
2013
Abstract
The paper presents the effects of fluid flow on the static and dynamic properties of carbon nanotubes that convey a viscous fluid. The mathematical model is based on the modified couple stress theory. The effects of various fluid parameters and boundary conditions on the pull-in voltages are investigated in detail. The applicability of the proposed system as nanovalves or nanosensors in nanoscale fluidic systems is elaborated. The results confirm that the nanoscale system studied in this paper can be properly applied for these purposes
Analysis of pull-in instability of electrostatically actuated carbon nanotubes using the homotopy perturbation method
, Article Journal of Mechanics of Materials and Structures ; Volume 8, Issue 8-10 , 2013 , Pages 385-401 ; 15593959 (ISSN) ; Rastgoo, A ; Ahmadian, M. T ; Sharif University of Technology
2013
Abstract
This paper analyzes the deflection and pull-in behaviors of cantilever and doubly clamped carbon nanotubes (CNTs) under electrostatic actuation using the homotopy perturbation method. The effects of electrostatic force and interatomic interactions on the deflection and pull-in instabilities of CNTs with different lengths, diameters, and boundary conditions are investigated in detail. The results reveal that larger diameters and shorter lengths result in higher pull-in voltages. Moreover, CNTs with doubly clamped boundary conditions, in comparison with cantilever boundary conditions, are more resistant to pull-in
Oscillatory behavior of an electrostatically actuated microcantilever gyroscope
, Article International Journal of Structural Stability and Dynamics ; Volume 13, Issue 6 , 2013 ; 02194554 (ISSN) ; Ahmadian, M. T ; Firoozbakhsh, K ; Sharif University of Technology
2013
Abstract
This paper is concerned with the study of the oscillatory behavior of an electrostatically actuated microcantilever gyroscope with a proof mass attached to its free end. In mathematical modeling, the effects of different nonlinearities such as electrostatic forces, fringing field, inertial terms and geometric nonlinearities are considered. The microgyroscope is subjected to bending oscillations around the static deflection coupled with base rotation. The primary oscillation is generated in drive direction of the microgyroscope by a pair of DC and AC voltages on the tip mass. The secondary oscillation occurring in the sense direction is induced by the Coriolis coupling caused by the input...
A coupled bending-torsion model for electrostatically actuated torsional nano/micro-actuators with considering influence of van der Waals force
, Article Acta Mechanica ; Volume 224, Issue 8 , 2013 , Pages 1791-1800 ; 00015970 (ISSN) ; Darvishian, A ; Ahmadian, M. T ; Sharif University of Technology
2013
Abstract
In the current paper, a coupled two degree of freedom model which considers both bending and torsion of the supporting torsion beams is presented for electrostatically actuated torsional nano/micro-actuators under the effect of van der Waals (vdW) force. Newton's second law is utilized for finding the normalized equations governing the static behavior of the actuator. The implict function theorem is then utilized for finding the equations governing the pull-in state of the actuator. The related results show that torsion model considerably overestimates the pull-in parameters of the nano/micro-actuator. The concept of the instability mode is introduced, and it is shown that when the ratio of...
Tip tracking control of a micro-cantilever Timoshenko beam via piezoelectric actuator
, Article JVC/Journal of Vibration and Control ; Volume 19, Issue 10 , 2013 , Pages 1561-1574 ; 10775463 (ISSN) ; Salarieh, H ; Alasty, A ; Shabani, R ; Sharif University of Technology
2013
Abstract
In this paper, the tip tracking control problem of a Timoshenko micro-cantilever beam is investigated. The beam is actuated by a piezoelectric layer laminated on one side of the beam. Dynamic equations of the beam and piezoelectric layer are found using the Hamilton principle. By employing the Galerkin projection method, state space representation of the system is derived. Then, a cascade control loop is used for tracking control of the beam's tip. The cascade control structure consists of an inner loop stabilizer and an outer loop proportional-integral-derivative controller. The stabilizer has a linear feedback form whose states are obtained through a linear observer which is based on the...