Abstract: In modern engineering, weight optimization has a priority during the design of structures. However, optimizing the weight can result in lower stiffness and less internal damping, causing the structure to become excessively prone to vibration. To overcome this problem, active or smart materials are implemented. The coupled electromechanical properties of smart materials, used in the form of piezoelectric ceramics in this work, make these materials well-suited for being implemented as distributed sensors and actuators to control the structural response. The smart structure proposed in this paper is composed of a cantilevered steel beam, an adhesive or bonding layer, and a piezoelectric actuator. The static deflection of the structure is derived as function of the piezoelectric voltage, and the outcome is compared to theoretical and experimental results from literature. The relation between the voltage and the piezoelectric moment at both ends of the actuator is also investigated and a reduced finite element model of the smart structure is created and verified. Finally, a linear controller is implemented and its ability to attenuate the vibration due to the first natural frequency is demonstrated.
Abstract: Connected vehicles are one of the promising technologies for future Intelligent Transportation Systems (ITS). A connected vehicle system is essentially a set of vehicles communicating through a network to exchange their information with each other and the infrastructure. Although this interconnection of the vehicles can be potentially beneficial in creating an efficient, sustainable, and green transportation system, a set of safety and reliability challenges come out with this technology. The first challenge arises from the information loss due to unreliable communication network which affects the control/management system of the individual vehicles and the overall system. Such scenario may lead to degraded or even unsafe operation which could be potentially catastrophic. Secondly, faulty sensors and actuators can affect the individual vehicle’s safe operation and in turn will create a potentially unsafe node in the vehicular network. Further, sending that faulty sensor information to other vehicles and failure in actuators may significantly affect the safe operation of the overall vehicular network. Therefore, it is of utmost importance to take these issues into consideration while designing the control/management algorithms of the individual vehicles as a part of connected vehicle system. In this paper, we consider a connected vehicle system under Co-operative Adaptive Cruise Control (CACC) and propose a fault diagnosis scheme that deals with these aforementioned challenges. Specifically, the conventional CACC algorithm is modified by adding a Kalman filter-based estimation algorithm to suppress the effect of lost information under unreliable network. Further, a sliding mode observer-based algorithm is used to improve the sensor reliability under faults. The effectiveness of the overall diagnostic scheme is verified via simulation studies.
Abstract: Fundamental basics of pure and applied research in the area of magneto-thermo-mechanical numerical analysis and design of innovative electromagnetic devices (modern induction heaters, novel thermoelastic actuators, rotating electrical machines, induction cookers, electrophysical devices) are elaborated. Thus, mathematical models of magneto-thermo-mechanical processes in electromagnetic devices taking into account main interactions of interrelated phenomena are developed. In addition, graphical representation of coupled (multiphysics) phenomena under consideration is proposed. Besides, numerical techniques for nonlinear problems solution are developed. On this base, effective numerical algorithms for solution of actual problems of practical interest are proposed, validated and implemented in applied 2D and 3D computer codes developed. Many applied problems of practical interest regarding modern electrical engineering devices are numerically solved. Investigations of the influences of various interrelated physical phenomena (temperature dependences of material properties, thermal radiation, conditions of convective heat transfer, contact phenomena, etc.) on the accuracy of the electromagnetic, thermal and structural analyses are conducted. Important practical recommendations on the choice of rational structures, materials and operation modes of electromagnetic devices under consideration are proposed and implemented in industry.
Abstract: In this paper, the influence of van der Waals, as well as electrostatic forces on the structural behavior of MEMS and NEMS actuators, has been investigated using of a Euler-Bernoulli beam continuous model. In the proposed nonlinear model, the electrostatic fringing-fields and the mid-plane stretching (geometric nonlinearity) effects have been considered. The nonlinear integro-differential equation governing the static structural behavior of the actuator has been derived. An original Galerkin-based reduced-order model has been developed to avoid problems arising from the nonlinearities in the differential equation. The obtained reduced-order model equations have been solved numerically using the Newton-Raphson method. The basic design parameters such as the pull-in parameters (voltage and deflection at pull-in), as well as the detachment length due to the van der Waals force of some investigated micro- and nano-actuators have been calculated. The obtained numerical results have been compared with some other existing methods (finite-elements method and finite-difference method) and the comparison showed good agreement among all assumed numerical techniques.
Abstract: In the SHP, LVDT sensor is for detecting the length
changes of the EHA output, and the thrust of the EHA is controlled by
the pressure sensor. Sensor is possible to cause hardware fault by
internal problem or external disturbance. The EHA of SHP is able to
be uncontrollable due to control by feedback from uncertain
information, on this paper; the sliding mode observer algorithm
estimates the original sensor output information in permanent sensor
fault. The proposed algorithm shows performance to recovery fault of
disconnection and short circuit basically, also the algorithm detect
various of sensor fault mode.
Abstract: Object manipulation techniques in robotics can be
categorized in two major groups including manipulation with grasp
and manipulation without grasp. The original aim of this paper is to
develop an object manipulation method where in addition to being
grasp-less, the manipulation task is done in a passive approach. In
this method, linear and angular positions of the object are changed
and its manipulation path is controlled. The manipulation path is a
helix track with constant radius and incline. The method presented in
this paper proposes a system which has not the actuator and the active
controller. So this system requires a passive mechanical intelligence
to convey the object from the status of the source along the specified
path to the goal state. This intelligent is created based on utilizing the
geometry of the system components. A general set up for the
components of the system is considered to satisfy the required
conditions. Then after kinematical analysis, detailed dimensions and
geometry of the mechanism is obtained. The kinematical results are
verified by simulation in ADAMS.
Abstract: Upon reviewing the literature and the pragmatic work done in the field of E- textiles, it is observed that the applications of wearable technologies have found a steady growth in the field of military, medical, industrial, sports; whereas fashion is at a loss to know how to treat this technology and bring it to market. The purpose of this paper is to understand the practical issues of integration of electronics in garments; cutting patterns for mass production, maintaining the basic properties of textiles and daily maintenance of garments that hinder the wide adoption of interactive fabric technology within Fashion and leisure wear. To understand the practical hindrances an experimental and laboratory approach is taken. “Techno Meets Fashion” has been an interactive fashion project where sensor technologies have been embedded with textiles that result in set of ensembles that are light emitting garments, sound sensing garments, proximity garments, shape memory garments etc. Smart textiles, especially in the form of textile interfaces, are drastically underused in fashion and other lifestyle product design. Clothing and some other textile products must be washable, which subjects to the interactive elements to water and chemical immersion, physical stress, and extreme temperature. The current state of the art tends to be too fragile for this treatment. The process for mass producing traditional textiles becomes difficult in interactive textiles. As cutting patterns from larger rolls of cloth and sewing them together to make garments breaks and reforms electronic connections in an uncontrolled manner. Because of this, interactive fabric elements are integrated by hand into textiles produced by standard methods. The Arduino has surely made embedding electronics into textiles much easier than before; even then electronics are not integral to the daily wear garments. Soft and flexible interfaces of MEMS (micro sensors and Micro actuators) can be an option to make this possible by blending electronics within E-textiles in a way that’s seamless and still retains functions of the circuits as well as the garment. Smart clothes, which offer simultaneously a challenging design and utility value, can be only mass produced if the demands of the body are taken care of i.e. protection, anthropometry, ergonomics of human movement, thermo- physiological regulation.
Abstract: In this work, we use the Fault detection and isolation and the Fault tolerant control based on sliding mode observer in order to introduce the well diagnosis of a nonlinear system. The robustness of the proposed observer for the two techniques is tested through a physical example. The results in this paper show the interaction between the Fault tolerant control and the Diagnosis procedure.
Abstract: Microcantilevers are the basic MEMS devices, which
can be used as sensors, actuators and electronics can be easily built
into them. The detection principle of microcantilever sensors is based
on the measurement of change in cantilever deflection or change in its
resonance frequency. The objective of this work is to explore the
analogies between mechanical and electrical equivalent of
microcantilever beams. Normally scientists and engineers working in
MEMS use expensive software like CoventorWare, IntelliSuite,
ANSYS/Multiphysics etc. This paper indicates the need of developing
electrical equivalent of the MEMS structure and with that, one can
have a better insight on important parameters, and their interrelation of
the MEMS structure. In this work, considering the mechanical model
of microcantilever, equivalent electrical circuit is drawn and using
force-voltage analogy, it is analyzed with circuit simulation software.
By doing so, one can gain access to powerful set of intellectual tools
that have been developed for understanding electrical circuits Later
the analysis is performed using ANSYS/Multiphysics - software based
on finite element method (FEM). It is observed that both mechanical
and electrical domain results for a rectangular microcantlevers are in
agreement with each other.
Abstract: In this paper, a robust fault detection and isolation
(FDI) scheme is developed to monitor a multivariable nonlinear
chemical process called the Chylla-Haase polymerization reactor,
when it is under the cascade PI control. The scheme employs a radial
basis function neural network (RBFNN) in an independent mode to
model the process dynamics, and using the weighted sum-squared
prediction error as the residual. The Recursive Orthogonal Least
Squares algorithm (ROLS) is employed to train the model to
overcome the training difficulty of the independent mode of the
network. Then, another RBFNN is used as a fault classifier to isolate
faults from different features involved in the residual vector. Several
actuator and sensor faults are simulated in a nonlinear simulation of
the reactor in Simulink. The scheme is used to detect and isolate the
faults on-line. The simulation results show the effectiveness of the
scheme even the process is subjected to disturbances and
uncertainties including significant changes in the monomer feed rate,
fouling factor, impurity factor, ambient temperature, and
measurement noise. The simulation results are presented to illustrate
the effectiveness and robustness of the proposed method.
Abstract: The objective of this work is to carryout critical
comparison of different actuation mechanisms like electrostatic,
thermal, piezoelectric, and magnetic with reference to a micro
cantilever. The relevant parameters like force generated,
displacement are compared in actuation methods. With these results,
helps in choosing the best actuation method for a particular
application. In this study, Comsol/Multiphysics software is used.
Modeling and simulation is done by considering the micro cantilever
of same dimensions as an actuator using all the above mentioned
actuation techniques. In addition to their small size, micro actuators
consume very little power and are capable of accurate results. In this
work, a comparison of actuation mechanisms is done to decide the
efficient system in micro domain.
Abstract: Piezoelectric actuator is treated as RC load when it is
modeled electrically. For some piezoelectric actuator applications,
arbitrary voltage is required to actuate. Especially for unidirectional
arbitrary voltage driving like as sine wave, some special inverter with
circuit that can charge and discharge the capacitive energy can be
used. In this case, the difference between power supply level and the
object voltage level for RC load is varied. Because the control gain is
constant, the controlled output is not uniform according to the voltage
difference. In this paper, for charge and discharge circuit for
unidirectional arbitrary voltage driving for piezoelectric actuator, the
controller gain is controlled according to the voltage difference. With
the proposed simple idea, the load voltage can have controlled
smoothly although the voltage difference is varied. The
appropriateness is proved from the simulation of the proposed circuit.
Abstract: Polyaniline is an indispensible component in lightemitting
devices (LEDs), televisions, cellular telephones, automotive,
corrosion-resistant coatings, actuators etc. The electrical conductivity
properties was found be increased by introduction of metal nano
particles. In the present study, an attempt has been made to utilize
platinum nano particles to achieve the improved electrical properties.
Polyaniline and Pt-polyaniline composite are synthesized by
electrochemical routes. X-ray diffractometer confirms the amorphous
nature of polyaniline. The Bragg’s diffraction peaks correspond to
platinum nanoparticles in Pt-polyaniline composite and
thermogravimetric analyzer indicates its decomposition at certain
temperature. The Scanning Electron Micrographs of colloidal
platinum nanoparticles were spherical, uniform shape in the
composite. The current-voltage (I-V) characteristics of the PANI and
composites were also studied which indicate a significant decreasing
resistivity than PANI-Platinum after introduction of pt nanoparticles
in the matrix of polyaniline (PANI).
Abstract: New design of three dimensional (3D) flywheel system
based on gimbal and gyro mechanics is proposed. The 3D flywheel
device utilizes the rotational motion of three spherical shells and the
conservation of angular momentum to achieve planar locomotion.
Actuators mounted to the ring-shape frames are installed within the
system to drive the spherical shells to rotate, for the purpose of steering
and stabilization. Similar to the design of 2D flywheel system, it is
expected that the spherical shells may function like a “flyball” to store
and supply mechanical energy; additionally, in comparison with
typical single-wheel and spherical robots, the 3D flywheel can be used
for developing omnidirectional robotic systems with better mobility.
The Lagrangian method is applied to derive the equation of motion of
the 3D flywheel system, and simulation studies are presented to verify
the proposed design.
Abstract: This paper presents the design and fabrication of a
novel piezoelectric actuator for a gas micro pump with check valve
having the advantages of miniature size, light weight and low power
consumption. The micro pump is designed to have eight major
components, namely a stainless steel upper cover layer, a piezoelectric
actuator, a stainless steel diaphragm, a PDMS chamber layer, two
stainless steel channel layers with two valve seats, a PDMS check
valve layer with two cantilever-type check valves and an acrylic
substrate. A prototype of the gas micro pump, with a size of 52 mm ×
50 mm × 5.0 mm, is fabricated by precise manufacturing. This device
is designed to pump gases with the capability of performing the
self-priming and bubble-tolerant work mode by maximizing the stroke
volume of the membrane as well as the compression ratio via
minimization of the dead volume of the micro pump chamber and
channel. By experiment apparatus setup, we can get the real-time
values of the flow rate of micro pump and the displacement of the
piezoelectric actuator, simultaneously. The gas micro pump obtained
higher output performance under the sinusoidal waveform of 250 Vpp.
The micro pump achieved the maximum pumping rates of 1185
ml/min and back pressure of 7.14 kPa at the corresponding frequency
of 120 and 50 Hz.
Abstract: The problem of finding control laws for underactuated
systems has attracted growing attention since these systems are
characterized by the fact that they have fewer actuators than the
degrees of freedom to be controlled. The acrobot, which is a planar
two-link robotic arm in the vertical plane with an actuator at the elbow
but no actuator at the shoulder, is a representative in underactuated
systems. In this paper, the dynamic model of the acrobot is
implemented using Mathworks’ Simscape. And the sliding mode
control is constructed using MATLAB and Simulink.
Abstract: New design of three dimensional (3D) flywheel system
based on gimbal and gyro mechanics is proposed. The 3D flywheel
device utilizes the rotational motion of three spherical shells and the
conservation of angular momentum to achieve planar locomotion.
Actuators mounted to the ring-shape frames are installed within the
system to drive the spherical shells to rotate, for the purpose of steering
and stabilization. Similar to the design of 2D flywheel system, it is
expected that the spherical shells may function like a “flyball” to store
and supply mechanical energy; additionally, in comparison with
typical single-wheel and spherical robots, the 3D flywheel can be used
for developing omnidirectional robotic systems with better mobility.
The Lagrangian method is applied to derive the equation of motion of
the 3D flywheel system, and simulation studies are presented to verify
the proposed design.
Abstract: This paper reports a novel actuating design that uses
the shear deformation of a piezoelectric actuator to deflect a
bulge-diaphragm for driving an array microdroplet ejector. In essence,
we employed a circular-shaped actuator poled radial direction with
remnant polarization normal to the actuating electric field for inducing
the piezoelectric shear effect. The array microdroplet ejector consists
of a shear type piezoelectric actuator, a vibration plate, two chamber
plates, two channel plates and a nozzle plate. The vibration, chamber
and nozzle plate components are fabricated using nickel
electroforming technology, whereas the channel plate is fabricated by
etching of stainless steel. The diaphragm displacement was measured
by the laser two-dimensional scanning vibrometer. The ejected
droplets of the microejector were also observed via an optic
visualization system.
Abstract: The paper presents a method for a simple and
immediate motion planning of a SCARA robot, whose end-effector
has to move along a given trajectory; the calculation procedure
requires the user to define in analytical form or by points the
trajectory to be followed and to assign the curvilinear abscissa as
function of the time. On the basis of the geometrical characteristics
of the robot, a specifically developed program determines the motion
laws of the actuators that enable the robot to generate the required
movement; this software can be used in all industrial applications for
which a SCARA robot has to be frequently reprogrammed, in order
to generate various types of trajectories with different motion times.
Abstract: The efficiency of the actuation system of exoskeletons
and active orthoses for lower limbs is a significant aspect of the
design of such devices because it affects their efficacy. The F-IVT is
an innovative actuation system to power artificial knee joint with
energy recovery capabilities. Its key and non-conventional elements
are a flywheel that acts as a mechanical energy storage system, and
an Infinitely Variable Transmission (IVT). The design of the F-IVT
can be optimized for a certain walking condition, resulting in a heavy
reduction of both the electric energy consumption and of the electric
peak power. In this work, by means of simulations of level ground
walking at different speeds, it is demonstrated that the F-IVT is still
an advantageous actuator which permits to save energy consumption
and to downsize the electric motor even when it does not work in
nominal conditions.