Abstract: Traditional mechanical control systems in thrust
vectoring are efficient in rocket thrust guidance but their costs
and their weights are excessive. The fluidic injection in the nozzle
divergent constitutes an alternative procedure to achieve the goal. In
this paper, we present a 3D analytical model for fluidic injection
in a supersonic nozzle integrating an orifice. The fluidic vectoring
uses a sonic secondary injection in the divergent. As a result, the
flow and interaction between the main and secondary jet has built in
order to express the pressure fields from which the forces and thrust
vectoring are deduced. Under various separation criteria, the present
analytical model results are compared with the existing numerical
and experimental data from the literature.
Abstract: Electrohydraulic servo system have been used in
industry in a wide number of applications. Its dynamics are highly
nonlinear and also have large extent of model uncertainties and
external disturbances. In this paper, a robust back-stepping control
(RBSC) scheme is proposed to overcome the problem of disturbances
and system uncertainties effectively and to improve the tracking
performance of EHS systems. In order to implement the proposed
control scheme, the system uncertainties in EHS systems are
considered as total leakage coefficient and effective oil volume. In
addition, in order to obtain the virtual controls for stabilizing system,
the update rule for the system uncertainty term is induced by
the Lyapunov control function (LCF). To verify the performance and
robustness of the proposed control system, computer simulation of
the proposed control system using Matlab/Simulink Software
is executed. From the computer simulation, it was found that the
RBSC system produces the desired tracking performance and has
robustness to the disturbances and system uncertainties of EHS
systems.
Abstract: The paper presents an advanced control system for
tennis ball throwing machines to improve their accuracy according to
the ball impact points. A further advantage of the system is the much
easier calibration process involving the intelligent solution of the
automatic adjustment of the stroking parameters according to the ball
elasticity, the self-calibration, the use of the safety margin at very flat
strokes and the possibility to placing the machine to any position of
the half court. The system applies mathematical methods to
determine the exact ball trajectories and special approximating
processes to access all points on the aimed half court.
Abstract: Numerical studies have been carried out using a
validated two-dimensional standard k-omega turbulence model for
the design optimization of a thrust vector control system using shock
induced self-impinging supersonic secondary double jet. Parametric
analytical studies have been carried out at different secondary
injection locations to identifying the highest unsymmetrical
distribution of the main gas flow due to shock waves, which produces
a desirable side force more lucratively for vectoring. The results from
the parametric studies of the case on hand reveal that the shock
induced self-impinging supersonic secondary double jet is more
efficient in certain locations at the divergent region of a CD nozzle
than a case with supersonic single jet with same mass flow rate. We
observed that the best axial location of the self-impinging supersonic
secondary double jet nozzle with a given jet interaction angle, built-in
to a CD nozzle having area ratio 1.797, is 0.991 times the primary
nozzle throat diameter from the throat location. We also observed
that the flexible steering is possible after invoking ON/OFF facility to
the secondary nozzles for meeting the onboard mission requirements.
Through our case studies we concluded that the supersonic self-impinging
secondary double jet at predesigned jet interaction angle
and location can provide more flexible steering options facilitating
with 8.81% higher thrust vectoring efficiency than the conventional
supersonic single secondary jet without compromising the payload
capability of any supersonic aerospace vehicle.
Abstract: Electrohydraulic servo system have been used in industry in a wide number of applications. Its dynamics are highly nonlinear and also have large extent of model uncertainties and external disturbances. In this paper, a robust back-stepping control (RBSC) scheme is proposed to overcome the problem of disturbances and system uncertainties effectively and to improve the tracking performance of EHS systems. In order to implement the proposed control scheme, the system uncertainties in EHS systems are considered as total leakage coefficient and effective oil volume. In addition, in order to obtain the virtual controls for stabilizing system, the update rule for the system uncertainty term is induced by the Lyapunov control function (LCF). To verify the performance and robustness of the proposed control system, computer simulation of the proposed control system using Matlab/Simulink Software is executed. From the computer simulation, it was found that the RBSC system produces the desired tracking performance and has robustness to the disturbances and system uncertainties of EHS systems.
Abstract: The article deals with the tool in Matlab GUI form
that is designed to analyse a mechatronic system sensitivity and
tolerance. In the analysed mechatronic system, a torque is transferred
from the drive to the load through a coupling containing flexible
elements. Different methods of control system design are used. The
classic form of the feedback control is proposed using Naslin method,
modulus optimum criterion and inverse dynamics method. The
cascade form of the control is proposed based on combination of
modulus optimum criterion and symmetric optimum criterion. The
sensitivity is analysed on the basis of absolute and relative sensitivity
of system function to the change of chosen parameter value of the
mechatronic system, as well as the control subsystem. The tolerance
is analysed in the form of determining the range of allowed relative
changes of selected system parameters in the field of system stability.
The tool allows to analyse an influence of torsion stiffness, torsion
damping, inertia moments of the motor and the load and controller(s)
parameters. The sensitivity and tolerance are monitored in terms of
the impact of parameter change on the response in the form of system
step response and system frequency-response logarithmic
characteristics. The Symbolic Math Toolbox for expression of the
final shape of analysed system functions was used. The sensitivity
and tolerance are graphically represented as 2D graph of sensitivity
or tolerance of the system function and 3D/2D static/interactive graph
of step/frequency response.
Abstract: This paper presents dynamic models of distributed
generators (DG) and investigates dynamic behavior of the DG units
in the micro grid system. The DG units include photovoltaic and fuel
cell sources. The voltage source inverter is adopted since the
electronic interface which can be equipped with its controller to keep
stability of the micro grid during small signal dynamics. This paper
also introduces power management strategies and implements the DG
load sharing concept to keep the micro grid operation in gridconnected
and islanding modes of operation. The results demonstrate
the operation and performance of the photovoltaic and fuel cell as
distributed generators in a micro grid. The entire control system in
the micro grid is developed by combining the benefits of the power
control and the voltage control strategies. Simulation results are all
reported, confirming the validity of the proposed control technique.
Abstract: Alone with fast urbanization in world, traffic control
became a big issue in urban construction. Having an efficient and
reliable traffic control system is crucial to macro-traffic control.
Traffic signal is used to manage conflicting requirement by allocating
different sets of mutually compatible traffic movement during distinct
time interval. Many approaches have been made proposed to solve
this discrete stochastic problem. Recognizing the need to minimize
right-of-way impacts while efficiently handling the anticipated high
traffic volumes, the proposed alternative system gives effective
design. This model allows for increased traffic capacity and reduces
delays by eliminating a step in maneuvering through the freeway
interchange. The concept proposed in this paper involves
construction of bridges and ramps at intersection of four roads to
control the vehicular congestion and to prevent traffic breakdown.
Abstract: This paper addresses the issue of the autonomous
mobile robot (AMR) navigation task based on the hybrid control
modes. The novel hybrid control mode, based on multi-sensors
information by using the fuzzy approach, has been presented in this
research. The system operates in real time, is robust, enables the robot
to operate with imprecise knowledge, and takes into account the
physical limitations of the environment in which the robot moves,
obtaining satisfactory responses for a large number of different
situations. An experiment is simulated and carried out with a pioneer
mobile robot. From the experimental results, the effectiveness and
usefulness of the proposed AMR obstacle avoidance and navigation
scheme are confirmed. The experimental results show the feasibility,
and the control system has improved the navigation accuracy. The
implementation of the controller is robust, has a low execution time,
and allows an easy design and tuning of the fuzzy knowledge base.
Abstract: Over the last few decades, oilfield service rolling
equipment has significantly increased in weight, primarily because of
emissions regulations, which require larger/heavier engines, larger
cooling systems, and emissions after-treatment systems, in some
cases, etc. Larger engines cause more vibration and shock loads,
leading to failure of electronics and control systems.
If the vibrating frequency of the engine matches the system
frequency, high resonance is observed on structural parts and mounts.
One such existing automated control equipment system comprising
wire rope mounts used for mounting computers was designed
approximately 12 years ago. This includes the use of an industrialgrade
computer to control the system operation. The original
computer had a smaller, lighter enclosure. After a few years, a newer
computer version was introduced, which was 10 lbm heavier. Some
failures of internal computer parts have been documented for cases in
which the old mounts were used. Because of the added weight, there
is a possibility of having the two brackets impact each other under
off-road conditions, which causes a high shock input to the computer
parts. This added failure mode requires validating the existing mount
design to suit the new heavy-weight computer.
This paper discusses the modal finite element method (FEM)
analysis and experimental modal analysis conducted to study the
effects of vibration on the wire rope mounts and the computer. The
existing mount was modelled in ANSYS software, and resultant
mode shapes and frequencies were obtained. The experimental modal
analysis was conducted, and actual frequency responses were
observed and recorded.
Results clearly revealed that at resonance frequency, the brackets
were colliding and potentially causing damage to computer parts. To
solve this issue, spring mounts of different stiffness were modeled in
ANSYS software, and the resonant frequency was determined.
Increasing the stiffness of the system increased the resonant
frequency zone away from the frequency window at which the engine
showed heavy vibrations or resonance. After multiple iterations in
ANSYS software, the stiffness of the spring mount was finalized,
which was again experimentally validated.
Abstract: Cross flow water tube heat exchanger can be designed
and made operational using methods of model building and
simulation of the system. This paper projects the design and
development of a model of cross flow water tube heat-exchanger
system, simulation and validation of control analysis of different
tuning methods. Feedback and override control system is developed
using inputs acquired with the help of sensory system. A
mathematical model is formulated for analysis of system behaviour.
The temperature is regulated at the desired set point automatically.
Abstract: Fuzzy inference method based approach to the
forming of modular intellectual system of assessment the quality of
communication services is proposed. Developed under this approach
the basic fuzzy estimation model takes into account the
recommendations of the International Telecommunication Union in
respect of the operation of packet switching networks based on IPprotocol.
To implement the main features and functions of the fuzzy
control system of quality telecommunication services it is used
multilayer feedforward neural network.
Abstract: Monocopter is a single-wing rotary flying vehicle
which has the capability of hovering. This flying vehicle includes two
dynamic parts in which more efficiency can be expected rather than
other Micro UAVs due to the extended area of wing compared to its
fuselage. Low cost and simple mechanism in comparison to other
vehicles such as helicopter are the most important specifications of
this flying vehicle.
In the previous paper we discussed the introduction of the final
system but in this paper, the experimental design process of
Monocopter and its control algorithm has been investigated in
general. Also the editorial bugs in the previous article have been
corrected and some translational ambiguities have been resolved.
Initially by constructing several prototypes and carrying out many
flight tests the main design parameters of this air vehicle were
obtained by experimental measurements. Eventually the required
main monocopter for this project was constructed. After construction
of the monocopter in order to design, implementation and testing of
control algorithms first a simple optic system used for determining
the heading angle. After doing numerous tests on Test Stand, the
control algorithm designed and timing of applying control inputs
adjusted. Then other control parameters of system were tuned in
flight tests. Eventually the final control system designed and
implemented using the AHRS sensor and the final operational tests
performed successfully.
Abstract: The development of the agricultural sector in Ghana
has been reliant on the use of irrigation systems to ensure food
security. However, the manual operation of these systems has not
facilitated their maximum efficiency due to human limitations.
This paper seeks to address this problem by designing and
implementing an efficient, cost effective automated system which
monitors and controls the water flow of irrigation through
communication with an authorized operator via text messages. The
automatic control component of the system is timer based with an
Atmega32 microcontroller and a real time clock from the SM5100B
cellular module. For monitoring purposes, the system sends periodic
notification of the system on the performance of duty via SMS to the
authorized person(s). Moreover, the GSM based Irrigation
Monitoring and Control System saves time and labour and reduces
cost of operating irrigation systems by saving electricity usage and
conserving water.
Field tests conducted have proven its operational efficiency and
ease of assessment of farm irrigation equipment due to its costeffectiveness
and data logging capabilities.
Abstract: This study proposes the transformation of nonlinear
Magnetic Levitation System into linear one, via state and feedback
transformations using explicit algorithm. This algorithm allows
computing explicitly the linearizing state coordinates and feedback
for any nonlinear control system, which is feedback linearizable,
without solving the Partial Differential Equations. The algorithm is
performed using a maximum of N-1 steps where N being the
dimension of the system.
Abstract: With demand for primary energy continuously
growing, search for renewable and efficient energy sources has been
high on agenda of our society. One of the most promising energy
sources is biogas technology. Residues coming from dairy industry
and milk processing could be used in biogas production; however,
low efficiency and high cost impede wide application of such
technology. One of the main problems is management and conversion
of organic residues through the anaerobic digestion process which is
characterized by acidic environment due to the low whey pH (
Abstract: The relationship between eigenstructure (eigenvalues
and eigenvectors) and latent structure (latent roots and latent vectors)
is established. In control theory eigenstructure is associated with
the state space description of a dynamic multi-variable system and
a latent structure is associated with its matrix fraction description.
Beginning with block controller and block observer state space forms
and moving on to any general state space form, we develop the
identities that relate eigenvectors and latent vectors in either direction.
Numerical examples illustrate this result. A brief discussion of the
potential of these identities in linear control system design follows.
Additionally, we present a consequent result: a quick and easy
method to solve the polynomial eigenvalue problem for regular matrix
polynomials.
Abstract: Static VAR System (SVS) is a kind of FACTS device which is used in power system primarily for the purpose of voltage and reactive power control. In this paper presents a systematic approach for designing SVS supplementary controller, which is used to improve the damping of power system oscillation. The combined bus voltage and line current (CBVLC) supplementary controller has been developed and incorporated in the SVS control system located at the middle of the series compensated long transmission line. Damping of torsional stresses due to subsynchronous resonance resulting from series capacitive compensation using CBVLC is investigated in this paper. Simulation results are carried out with MATLAB/Simulink on the IEEE first benchmark model (FBM). The simulation results show that the oscillations are satisfactorily damped out by the SVS supplementary controller. Time domain simulation is performed on power system and the results demonstrate the effectiveness of the proposed controller.
Abstract: Assistive robotics are playing a vital role in advancing the quality of life for disable people. There exist wide range of systems that can control and guide autonomous mobile robots. The objective of the control system is to guide an autonomous mobile robot using the movement of eyes by means of EOG signal. The EOG signal is acquired using Ag/AgCl electrodes and this signal is processed by a microcontroller unit to calculate the eye gaze direction. Then according to the guidance control strategy, the control commands of the wheelchair are sent. The classification of different eye movements allows us to generate simple code for controlling the wheelchair. This work was aimed towards developing a usable and low-cost assistive robotic wheel chair system for disabled people. To live more independent life, the system can be used by the handicapped people especially those with only eye-motor coordination.
Abstract: In this paper, fractional order feedback control of a ball
beam model is investigated. The ball beam model is a particular
example of the double Integrator system having strongly nonlinear
characteristics and unstable dynamics which make the control of
such system a challenging task. Most of the work in fractional order
control systems are in theoretical nature and controller design and its
implementation in practice is very small. In this work, a successful
attempt has been made to design a fractional order PIλDμcontroller
for a benchmark laboratory ball and beam model. Better performance
can be achieved using a fractional order PID controller and it is
demonstrated through simulations results with a comparison to the
classic PID controller.