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Research field: Sensor & Actuator, Levitation
Expert: َAlizade
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This paper presents a mechanism for linear movement which could be called threadless screw, in which a roller is pushed toward a rotating plain shaft and rotates with it. The roller moves on a helical path when its axis is not parallel to the axis of the shaft. Therefore, the roller moves in direction of the shaft axis, just as linear movement of a nut on a screw. The lead of this mechanism is not only a function of diameter of the shaft, but also the angle between axes of the roller and the shaft which gives the possibility to change the lead continuously from very fine to very rough leads. On the other hand the accuracy of this mechanism depends on the accuracy of a plain cylindrical surface which can be fabricated very accurately compare
Self-sensing feature allows an actuator to be used as a sensor. Magnetoelectric (ME) composites consist of piezoelectric and magnetostrictive layers. ME composite is a proper candidate for the self-sensing feature in a wireless actuator due to its concurrent magnetic-charge order. In this study, the self-sensing feature of a nano-displacement ME actuator is investigated. The ME structure design, as well as the effect of geometric parameter and resonance frequency on the ME signal, is evaluated using a numerical modeling. The Metglas/PMN-PT/Metglas composite was fabricated as an ME actuator. The displacement measurement was conducted using a laser Doppler. The effect of bias field and excitation frequency on sensitivity, linearity, resolutio
Electrical current is usually used to change the damping force of Magnetorheological Dampers (MRDs). However, changing the electrical current could shift the stiffness of the system, the phenomenon that was not considered carefully. This study aims to evaluate this shift. A typical MRD was designed, optimized, and fabricated to do some accurate and detailed experimental tests to examine the stiffness variation. The damper is equipped with a circulating system to prevent the deposition of particles when it is at rest. Besides that, a vibration setup was developed for the experimental study. It is capable of generating vibration with either constant frequency or frequency sweep and measure the amplitude of vibration. The damper was tested by
This open-access journal is published under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License which permits Share (copy and redistribute the material in any medium or format) and Adapt (remix, transform, and build upon the material) under the Attribution-NonCommercial terms.
This open-access journal is published under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License which permits Share (copy and redistribute the material in any medium or format) and Adapt (remix, transform, and build upon the material) under the Attribution-NonCommercial terms.
In this paper, extensive testing on an electrostatic wall-climbing robot is carried out to examine the electrostatic adhesion force when using the Free Flapping Foils (FFF) method. This method is successfully applied to an electrostatic robot to enable it to stick more firmly, by about three times, on walls with different materials, including wood, plaster, granite, glass and climb wall with a continuous movement. The innovation in this paper is that successful tests were carried out, when using thin flexible electrodes made from aluminium foil and free movement of those electrodes. The FFF electrodes are flexible enough to get the shape and roughness of the wall and increases the contact surface. Thus, they increase the adhesion force and
In this study, a new method was proposed for the design of composite magnetoelectric actuator. Design of experiment (DOE) was utilized to investigate the mutual effect of geometric parameters. Moreover, the effect of impedance phase angle, magnetic field, and bias field were studied through finite element (FE) modeling. Resonance frequency, displacement value, magnetoelectric coefficient, and mode shape were considered as response variables. Analysis of variance (ANOVA), regression modeling and response surface method (RSM) were used to investigate the pair-wise effect of input parameters on the response variables. ANOVA results showed that the magnetoelectric length and piezoelectric thickness are the most important parameters affecting th
This paper presents a theoretical study of nonlinear dynamic behavior of a dielectric elastomer minimum energy structure (DEMES). While planar Dielectric Elastomer Actuators (DEA) solely poses material nonlinearity in their model, geometrical nonlinearity imposes additional challenge to model DEMES. Considering dielectric elastomer and bending frame, respectively, as a hyper-elastic film and an elastic beam, Euler–Lagrange equation is employed to derive the equation of motion of actuator subject to a harmonic voltage. Fixed point analysis of the equation of motion demonstrates supercritical pitchfork bifurcation with respect to film pre-stretch as bifurcation parameter. It is shown by simulation results that the system poss
A piezoelectric paper feeder actuator using Micro Virtual Roller (MVR) is proposed, designed, fabricated and tested. This actuator can drive a sheet of paper forward or backward without any mechanical parts, such as the costly and heavy rollers used in traditional paper feeders. In this paper feeder actuator, two vibrating stators which produce traveling waves are used to drive the paper. The vibrations of the stators are similar to those of piezoelectric motors and follow a similar procedure to move the paper. A feasibility study simulated the actuator in COMSOL Multiphysics Software. Traveling wave and elliptical trajectories were obtained and the dimensions of the stator were optimized using FEM so that the paper could move at top speed.
The global green economy mechanism is considered in some international environmental documents to achieve sustainable development. Promoting environmental-friendly technologies, protecting natural capital, improving employment and reducing poverty, along with expanding investment and technology, are based on green economy policies. Green taxation is one of the tools of the green economy policy for the deployment of sustainable technologies. This research is based on the analysis of law and environmental documents with the green economy approach. From the most important green tax strengths, weaknesses, opportunities and threats (SWOT) has been identified in this paper, deployment of environmentally friendly technologies, the possibility of r
For detecting cells by Surface Acoustic Wave sensors, a sacrificial layer with antigens is usually used to trap cells. This paper introduces a new idea where Dielectrophoresis force traps target cells instead of a sacrificial layer that reacts with target cells and sensed by the surface acoustic wave. Therefore, one can use the sensors more than once, and it is possible to trap different types of cells with different dielectric properties. The device is simulated, and the main parameters of a Dielectrophoresis trapping system and Surface Acoustic Wave sensor, have been introduced and optimized. The effects of focused and unfocused electrode are studied numerically on the displacement of the sensor. Eventually, the feasibility of using the h
In this study, high-temperature tensile behavior of Al-3 vol% SiC nanocomposite is investigated. To fabricate the samples, SiC nano reinforcements and Al matrix were mixed using an attrition milling. The mixed powders were then subjected to cold pressing and hot extrusion at temperature of 500? C. Tensile behavior at different temperatures along with density measurement and microstructural examinations were studied. The results represent a 40% improvement in ultimate tensile strength of Al-3vol% SiC nanocomposite in comparison with non-reinforced sample at ambient temperature. Also, a rise in temperature up to 270 ? C during the tensile test led to an increase of the maximum elongation. Moreover, this temperature rise caused to 50% and 44%
In this paper, a hybrid damper is developed to achieve lower stiffness compared to magneto rheological dampers. The hybrid damper consists of an eddy current damper (ECD) and a Magneto Rheological Damper (MRD). The aim of this research is to reduce the stiffness of MRDs with equal damping forces. This work is done by adding an eddy current passive damper to a semi-active MRD. The ECDs are contactless dampers which show an almost viscous damping behavior without increasing the stiffness of a system. However, MRDs increase damping and stiffness of a system simultaneously, when a magnetic field is applied. Damping of each part is studied theoretically and experimentally. A semi-empirical model is developed to explain the viscoelastic behavior
Dielectrophoresis is a phenomenon with wide application in the cell sorting system, in which the dielectrophoresis force acts on a dielectric particle located in the non-uniform electric field. In this study, governing equations on this phenomenon are presented and a new method for measuring dielectrophoresis force is developed. This method is based on measuring drag force on particle and solving the equilibrium equations. For this purpose drag force is measured in two directions, parallel and perpendicular to electrodes. To evaluate the method, an actuator has been developed which has paralleled electrodes with 50 widths and 50 intervals and a PDMS channel with height of 80 is mounted on them. In experimental result, the exerted dielectrop
This paper presents a conceptual design and control of a novel gasoline direct injector (GDI) using giant magnetostricitve material, Terfenol-D, as an actuation component. Electromagnetic and fluid analyses are accomplished to investigate the influence of some parameters, such as nozzle length, pressure of input fuel, and cone angle of injector's needle. Experimental results obtained from fabricated GDI show good agreement with the numerical results provided by the 3-D finite-element analysis. Furthermore, the fabricated GDI is controlled by fuzzy and PID controllers. It was shown that fuzzy controllers provide faster response with less accuracy compared to the PID controller. Consequently, there is a tradeoff between fast response and stea
Among all particle separation approaches, dielectrophoresis actuators which use electric properties difference between particles, have turned into strong separating tools. This way, the particles in the fluid within non-uniform electric field experience the dielectrophoresis force. The amount and direction of this force depend on the fluid and particle polarization, particle size and electric field gradient. In this paper after presenting governing equations concerning the dielectrophoresis phenomenon, a microfluidic actuator introduced in which an interdigitated electrode pattern is applied in. Voltage, pitch, and width to pitch ratio of electrode as well as channel height are of the most important geometrical parameters of this actuator w
This article presents a design and development of a drop-on-demand (DOD) droplets generator. This generator uses molten metal as a liquid and can be used in fabrication, prototyping and any kind of printing with solder droplets. This setup consists of a vibrator solenoid with tunable frequency to produce a semi-spherical shape of molten metal, close to the surface of fabrication. This design also has a nozzle with micro-size orifice, a rod for transmitting force and a heater to melt the metal and keep it in superheat temperature. This DOD can produce droplets in different sizes (less than 550 ?m) by controlling the vibration frequency of solenoid. This ability together with the accuracy of the droplets in positioning (the error is less than