Màster universitari en Enginyeria Mecànica - EMMME
http://hdl.handle.net/2099.1/4489
2016-09-24T20:56:03ZNumerical simulation of condensation in a supersonic nozzle for application to ejectors in refrigeration
http://hdl.handle.net/2117/81010
Numerical simulation of condensation in a supersonic nozzle for application to ejectors in refrigeration
Gallach Palma, Marina
This thesis is a CFD study of a supersonic nozzle for ejector refrigeration applications.
Condensation of the working
uid is aimed inside the nozzle in order to study its conse-
quences. As a first approach to verify the built-in Wet Steam model in ANSYS Fluent,
a Laval nozzle is tested with water and compared with experimental data from Moses
and Stein.
Thanks to the User Defined Wet Steam Property Functions in the User Defined Wet
Steam model, the code is adapted for R134a both ideal and real gas properties and the
study is done with perfect and real gas properties. Anyway, the software presents certain
limitations and the real gas Peng-Robinson Equation Of State could not be implemented
due to convergence problems.
2015-12-22T18:47:29ZGallach Palma, MarinaThis thesis is a CFD study of a supersonic nozzle for ejector refrigeration applications.
Condensation of the working
uid is aimed inside the nozzle in order to study its conse-
quences. As a first approach to verify the built-in Wet Steam model in ANSYS Fluent,
a Laval nozzle is tested with water and compared with experimental data from Moses
and Stein.
Thanks to the User Defined Wet Steam Property Functions in the User Defined Wet
Steam model, the code is adapted for R134a both ideal and real gas properties and the
study is done with perfect and real gas properties. Anyway, the software presents certain
limitations and the real gas Peng-Robinson Equation Of State could not be implemented
due to convergence problems.Design of an adaptive brake pressure controller for the antilock braking system
http://hdl.handle.net/2099.1/24083
Design of an adaptive brake pressure controller for the antilock braking system
Torres Sabaté, Roger
In the past few decades, the introduction of electronics in motor vehicles has marked its
development. At the beginning, electronic systems were used to control the engine
(electronic fuel-injection systems). From that time on, electronic components entered the domain of driving safety (e.g. the Anti-lock Braking System, Electronics Stability Control or the Adaptive Cruise Control) up to the point that completely new fields of application have emerged in the areas of driving assistance, communication and infotainment as a result of continuous improvements in semiconductor technology.
This thesis is focused on the second component mentioned, the Anti-lock Braking System (ABS). Specifically, the ABS prevents the wheels from locking when the brakes are
applied by detecting incipient wheel lock on one or more wheels and makes sure that both
lateral and longitudinal friction are optimal by dynamically controlling the brake pressure of individual wheels. By doing so, wheels are prevented from locking up, the braking distance is minimized and the vehicle remains steerable.
The Electronic Control Unit (ECU) contains, among others, the ABS functionality, which
is comprised by two main parts: the high level ABS algorithm and the low level brake
pressure control. The first sends a pressure request signal - determined from complex
control systems based on heuristic rules - to the pressure controller, which has to be
applied on the desired brake pad precisely.
This work is focused on the low level control in order to make it as precise as possible and perform optimally with changing hydraulic system characteristics. By carrying out a wide analysis of response data with the current feed-forward controller structure, its system characteristics and key parameters have been identified. This has been possible thanks to a partnership between TU Delft and SKF, from which a BMW 5 series test vehicle has been acquired and modified for any kind of safety control system, such as the installation of active suspension, force sensing bearings or the hereby needed hydraulic ABS circuit modification.
The main outcome of the first part of the work is the definition of a new model which, a part from considering the voltage as a new input for the pressure step estimation,
improves the build up phase accuracy more than a 10% by smoothing the compressibility
effect of the brake fluid.
The second part of the work focuses on the design of an Adaptive Brake Pressure
Controller which is based on an adaptive mapping continuously updated by the Recursive
Least Squares algorithm. The results are quite promising. Indeed, this novel control
system is expected to increase the accuracy of the initial controller more than a 40%
while adapting to the changing-system, thus accomplishing the main objectives of this
work. Furthermore, the smaller pressure steps, the main drawback of the previous feedback controller, are presumably going to be accurately reached.
Last section of this chapter suggests different methodologies to determine the quality of the new designed adaptive control system which, if proved to be successful, would be a great step in the development of this important active safety control system which is the Anti-lock Braking System.
2014-12-01T17:57:22ZTorres Sabaté, RogerIn the past few decades, the introduction of electronics in motor vehicles has marked its
development. At the beginning, electronic systems were used to control the engine
(electronic fuel-injection systems). From that time on, electronic components entered the domain of driving safety (e.g. the Anti-lock Braking System, Electronics Stability Control or the Adaptive Cruise Control) up to the point that completely new fields of application have emerged in the areas of driving assistance, communication and infotainment as a result of continuous improvements in semiconductor technology.
This thesis is focused on the second component mentioned, the Anti-lock Braking System (ABS). Specifically, the ABS prevents the wheels from locking when the brakes are
applied by detecting incipient wheel lock on one or more wheels and makes sure that both
lateral and longitudinal friction are optimal by dynamically controlling the brake pressure of individual wheels. By doing so, wheels are prevented from locking up, the braking distance is minimized and the vehicle remains steerable.
The Electronic Control Unit (ECU) contains, among others, the ABS functionality, which
is comprised by two main parts: the high level ABS algorithm and the low level brake
pressure control. The first sends a pressure request signal - determined from complex
control systems based on heuristic rules - to the pressure controller, which has to be
applied on the desired brake pad precisely.
This work is focused on the low level control in order to make it as precise as possible and perform optimally with changing hydraulic system characteristics. By carrying out a wide analysis of response data with the current feed-forward controller structure, its system characteristics and key parameters have been identified. This has been possible thanks to a partnership between TU Delft and SKF, from which a BMW 5 series test vehicle has been acquired and modified for any kind of safety control system, such as the installation of active suspension, force sensing bearings or the hereby needed hydraulic ABS circuit modification.
The main outcome of the first part of the work is the definition of a new model which, a part from considering the voltage as a new input for the pressure step estimation,
improves the build up phase accuracy more than a 10% by smoothing the compressibility
effect of the brake fluid.
The second part of the work focuses on the design of an Adaptive Brake Pressure
Controller which is based on an adaptive mapping continuously updated by the Recursive
Least Squares algorithm. The results are quite promising. Indeed, this novel control
system is expected to increase the accuracy of the initial controller more than a 40%
while adapting to the changing-system, thus accomplishing the main objectives of this
work. Furthermore, the smaller pressure steps, the main drawback of the previous feedback controller, are presumably going to be accurately reached.
Last section of this chapter suggests different methodologies to determine the quality of the new designed adaptive control system which, if proved to be successful, would be a great step in the development of this important active safety control system which is the Anti-lock Braking System.Design and manufacturing of the Nub3d Sidio inspect body
http://hdl.handle.net/2099.1/20484
Design and manufacturing of the Nub3d Sidio inspect body
Hedian Martinez, Jorge
This final Project has involved the redesigning and manufacturing of the body of a 3D scanner called Sidio Inspect. The main components of this scanner are the projector, a camera along with all the necessary hardware to connect them and scan the objects and a computer to receive, process the information and generate the images. This scanner is capable of generating complete tri-dimensional images of any physical object with the intention of performing a dimensional control. It is built to be mounted on a robotic arm on an assembly line and inspect all the assemblies or manufactured components so that any imperfections in the different processes can be detected quickly, efficiently while preventing them from continuing in the assembly line which will save substantial costs at the end of the assembly process. The current prototype is poorly constructed; it is built using unconventional manufacturing processes that will not protect the delicate and expensive internal components in case of an accidental impact. It does not offer proper cooling for the projector and it’s not properly sealed to prevent impurities from entering the system. The new mechanical design of the body will fix these current problems and improve the scanner capabilities all within the given budget and time constraints given by the company.
2014-01-27T17:28:30ZHedian Martinez, JorgeThis final Project has involved the redesigning and manufacturing of the body of a 3D scanner called Sidio Inspect. The main components of this scanner are the projector, a camera along with all the necessary hardware to connect them and scan the objects and a computer to receive, process the information and generate the images. This scanner is capable of generating complete tri-dimensional images of any physical object with the intention of performing a dimensional control. It is built to be mounted on a robotic arm on an assembly line and inspect all the assemblies or manufactured components so that any imperfections in the different processes can be detected quickly, efficiently while preventing them from continuing in the assembly line which will save substantial costs at the end of the assembly process. The current prototype is poorly constructed; it is built using unconventional manufacturing processes that will not protect the delicate and expensive internal components in case of an accidental impact. It does not offer proper cooling for the projector and it’s not properly sealed to prevent impurities from entering the system. The new mechanical design of the body will fix these current problems and improve the scanner capabilities all within the given budget and time constraints given by the company.Estudio de la evolución de la rugosidad en un proceso de pulido de una superficie rectificada
http://hdl.handle.net/2099.1/17660
Estudio de la evolución de la rugosidad en un proceso de pulido de una superficie rectificada
Baró Rius, Oscar
En el presente trabajo fin de máster se ha estudiado la evolución de la rugosidad
superficial de un acero para moldes, que se ha rectificado bajo diferentes condiciones y
posteriormente se ha sometido a sucesivos procesos de pulido.
Se han realizado diferentes rectificados a unas probetas de acero templado, Wr.12344,
material utilizado habitualmente para la fabricación de moldes. Posteriormente, las
probetas han sido sometidas a un proceso de pulido con abrasivo de corindón de tamaño
2500 escala Norton. Los datos de rugosidad obtenidos mediante un rugosímetro de
contacto han servido para analizar su evolución. Se han estudiado diferentes parámetros
de rugosidad, Ra, Rq, Rt, Rk, Rpk, Rvk, Mr1, Mr2, Rku, Rsk, así como las curvas de
Abbott-Firestone y las curvas de probabilidad para cada una de las fases del proceso de
pulido. Se han propuesto distintos criterios para la determinación del tiempo de pulido:
evolución de Ra, evolución de las curvas de Abbot-Firestone o evolución de las curvas
de probabilidad. En los tres casos se ha considerado como tiempo de pulido el necesario
para que los resultados obtenidos en la dirección longitudinal y transversal coincidan.
Además de las pruebas de pulido se han llevado a cabo varios estudios
complementarios, tales como: determinación del cut-off óptimo, estudio de la
variabilidad entre réplicas de un mismo ensayo, estudio sobre el porcentaje de material
idóneo para comparar diferentes curvas de Abbott-Firsetone, así como la sensibilidad de
los parámetros de amplitud de rugosidad a una imperfección en la superficie.
Los resultados muestran que el parámetro que más influye sobre la topografía
superficial obtenida en rectificado es el tamaño de grano de la muela. La rugosidad
sigue una evolución exponencial con el tiempo, excepto para el parámetro Rpk que
disminuye muy rápido y Rvk que disminuye muy lento. Rku y Rsk son muy sensibles a
irregularidades en la superficie. Se recomienda emplear los parámetros de probabilidad
en el estudio de piezas fabricadas mediante rectificado y posterior pulido. Entre los
criterios estudiados para determinar el tiempo de pulido, es aconsejable utilizar las
curvas de Abbott-Firestone o las de probabilidad, considerando como tiempo de pulido
el necesario para que los resultados de las medidas longitudinal y transversal coincidan.
2013-03-15T16:23:13ZBaró Rius, OscarEn el presente trabajo fin de máster se ha estudiado la evolución de la rugosidad
superficial de un acero para moldes, que se ha rectificado bajo diferentes condiciones y
posteriormente se ha sometido a sucesivos procesos de pulido.
Se han realizado diferentes rectificados a unas probetas de acero templado, Wr.12344,
material utilizado habitualmente para la fabricación de moldes. Posteriormente, las
probetas han sido sometidas a un proceso de pulido con abrasivo de corindón de tamaño
2500 escala Norton. Los datos de rugosidad obtenidos mediante un rugosímetro de
contacto han servido para analizar su evolución. Se han estudiado diferentes parámetros
de rugosidad, Ra, Rq, Rt, Rk, Rpk, Rvk, Mr1, Mr2, Rku, Rsk, así como las curvas de
Abbott-Firestone y las curvas de probabilidad para cada una de las fases del proceso de
pulido. Se han propuesto distintos criterios para la determinación del tiempo de pulido:
evolución de Ra, evolución de las curvas de Abbot-Firestone o evolución de las curvas
de probabilidad. En los tres casos se ha considerado como tiempo de pulido el necesario
para que los resultados obtenidos en la dirección longitudinal y transversal coincidan.
Además de las pruebas de pulido se han llevado a cabo varios estudios
complementarios, tales como: determinación del cut-off óptimo, estudio de la
variabilidad entre réplicas de un mismo ensayo, estudio sobre el porcentaje de material
idóneo para comparar diferentes curvas de Abbott-Firsetone, así como la sensibilidad de
los parámetros de amplitud de rugosidad a una imperfección en la superficie.
Los resultados muestran que el parámetro que más influye sobre la topografía
superficial obtenida en rectificado es el tamaño de grano de la muela. La rugosidad
sigue una evolución exponencial con el tiempo, excepto para el parámetro Rpk que
disminuye muy rápido y Rvk que disminuye muy lento. Rku y Rsk son muy sensibles a
irregularidades en la superficie. Se recomienda emplear los parámetros de probabilidad
en el estudio de piezas fabricadas mediante rectificado y posterior pulido. Entre los
criterios estudiados para determinar el tiempo de pulido, es aconsejable utilizar las
curvas de Abbott-Firestone o las de probabilidad, considerando como tiempo de pulido
el necesario para que los resultados de las medidas longitudinal y transversal coincidan.Evaluation of the method: Computational modeling of Jominy test with variable thermal properties using finite elements
http://hdl.handle.net/2099.1/14757
Evaluation of the method: Computational modeling of Jominy test with variable thermal properties using finite elements
Caicedo Casas, Juan Manuel
With the introduction of numerical methods, combined with powerful
computational resources, a larger amount of problems of higher complexity
could be solved compared to those solved by analytical methods.
Analytical solutions, implied at the same time, huge efforts by means of
complex mathematical formulation, and solution were restricted to a
reduced number of physical problems. Research in numerical methods is
being held all around the globe, and an important number of papers in
many different areas are being published year after year.
The main goal achieved by introducing numerical methods solutions is the
possibility this methods gives, in order to obtain a closer-to-reality nonlinear
solution, taking into account real geometry, non-independent
material’s properties, initial and boundary conditions, and the evolution in
time of geometry, material properties and boundary conditions.
Jominy test (ASTM A255, SAE J406, ISO 642 / A04-303), is one of those
physical test were an analytical solution could not be obtained due the
dependence with temperature of material properties as density, specific
heat capacity and thermal conduction. In this thesis, two different ways of
modeling Jominy test by means of Finite Element Method are presented
and compared. The first one is a series of MATLAB! codes, based on
finite element theory, where Parabolic First Order Heat Conduction
Equation is taken from its continuous time-space domain form, into the
discrete time- space domain. In second place, modeling with CAM
commercial software ANSYS! is being held, in order to obtain a solution
with a proved, well known, CAM software, which allows having trustful
results to compare with. Axisymmetric condition is taking into account to
reduce the number of axis without losing any accuracy in both,
MATLAB! and ANSYS! solutions. An Experimental framework chapter has been added in order to give a
better understanding of Jominy test experiment for readers not related to it.
It is, indeed, a general overview of the experiment. For a detailed
explanation of the procedure it would be necessary for the reader to acquire
the ASTM A255 standard of Jominy test, or any equivalent standard (SAE
J406, ISO 642/ A04-303). The reader can find technical results from the
test in [7], pages 323 and 324. If related with Jominy test, skip chapter one,
Experimental Framework, as this introductory chapter is intended, as said
before, to readers not related with the experiment in order to establish
necessary background for a better understand of the work presented
thereafter.
Thesis is centered in the numerical results, the main objective is the to be
able to conclude if the numerical algorithm implemented in MATLAB!
represents indeed the real test, by means of comparing results with
simulations made using a high level commercial proved CAM software
ANSYS!. A complete and deep explanation of the Theoretical background
related with the project is exposed in chapter 2 Theoretical Framework,
including, among others, Thermal Parabolic first order equation reigning
physical behavior of the specimen submitted to Jominy test, the finite
element method applied to the heat-transfer equation, as well as finite
difference method used later on in the time-domain.
Special care was put into ensure compatibility between both results in order
to make the analysis. Enhances have being done in order this comparison
could take place and resemble most likely to the real test conditions: A
variable mesh, closer to the real thermocouples position, was employed in
both programs. In the variable mesh, implicit methods in time were
implemented, and an easy to comprehend postprocessor was developed.
Motivation for overtaking this thesis lies in observing the correlation in
results obtained by own means, compared to those obtained by a trustful
source, and this is the most important feature of the thesis. As expected,
differences between two solutions are found, but same shape and similar
gradient of temperature are obtained, proving the validity of previous
results.
2012-03-14T18:01:47ZCaicedo Casas, Juan ManuelWith the introduction of numerical methods, combined with powerful
computational resources, a larger amount of problems of higher complexity
could be solved compared to those solved by analytical methods.
Analytical solutions, implied at the same time, huge efforts by means of
complex mathematical formulation, and solution were restricted to a
reduced number of physical problems. Research in numerical methods is
being held all around the globe, and an important number of papers in
many different areas are being published year after year.
The main goal achieved by introducing numerical methods solutions is the
possibility this methods gives, in order to obtain a closer-to-reality nonlinear
solution, taking into account real geometry, non-independent
material’s properties, initial and boundary conditions, and the evolution in
time of geometry, material properties and boundary conditions.
Jominy test (ASTM A255, SAE J406, ISO 642 / A04-303), is one of those
physical test were an analytical solution could not be obtained due the
dependence with temperature of material properties as density, specific
heat capacity and thermal conduction. In this thesis, two different ways of
modeling Jominy test by means of Finite Element Method are presented
and compared. The first one is a series of MATLAB! codes, based on
finite element theory, where Parabolic First Order Heat Conduction
Equation is taken from its continuous time-space domain form, into the
discrete time- space domain. In second place, modeling with CAM
commercial software ANSYS! is being held, in order to obtain a solution
with a proved, well known, CAM software, which allows having trustful
results to compare with. Axisymmetric condition is taking into account to
reduce the number of axis without losing any accuracy in both,
MATLAB! and ANSYS! solutions. An Experimental framework chapter has been added in order to give a
better understanding of Jominy test experiment for readers not related to it.
It is, indeed, a general overview of the experiment. For a detailed
explanation of the procedure it would be necessary for the reader to acquire
the ASTM A255 standard of Jominy test, or any equivalent standard (SAE
J406, ISO 642/ A04-303). The reader can find technical results from the
test in [7], pages 323 and 324. If related with Jominy test, skip chapter one,
Experimental Framework, as this introductory chapter is intended, as said
before, to readers not related with the experiment in order to establish
necessary background for a better understand of the work presented
thereafter.
Thesis is centered in the numerical results, the main objective is the to be
able to conclude if the numerical algorithm implemented in MATLAB!
represents indeed the real test, by means of comparing results with
simulations made using a high level commercial proved CAM software
ANSYS!. A complete and deep explanation of the Theoretical background
related with the project is exposed in chapter 2 Theoretical Framework,
including, among others, Thermal Parabolic first order equation reigning
physical behavior of the specimen submitted to Jominy test, the finite
element method applied to the heat-transfer equation, as well as finite
difference method used later on in the time-domain.
Special care was put into ensure compatibility between both results in order
to make the analysis. Enhances have being done in order this comparison
could take place and resemble most likely to the real test conditions: A
variable mesh, closer to the real thermocouples position, was employed in
both programs. In the variable mesh, implicit methods in time were
implemented, and an easy to comprehend postprocessor was developed.
Motivation for overtaking this thesis lies in observing the correlation in
results obtained by own means, compared to those obtained by a trustful
source, and this is the most important feature of the thesis. As expected,
differences between two solutions are found, but same shape and similar
gradient of temperature are obtained, proving the validity of previous
results.Desarrollo de metodología para evaluación mecánica de una junta soldada en "T"
http://hdl.handle.net/2099.1/10746
Desarrollo de metodología para evaluación mecánica de una junta soldada en "T"
Vieira de Castro, Felipe
Se realizó el estudio del comportamiento mecánico de una unión soldada en “T” con láminas
de acero UNE F1 utilizando electrodos revestidos AWS E-6013 con la finalidad de realizar un
aporte en referencia a los procedimientos de cálculo de ésta. Para ello, en primer lugar, se
efectuaron cálculos de interés con la finalidad de obtener la resistencia máxima de la junta
soldada y la magnitud de los esfuerzos utilizando fórmulas obtenidas de la teoría fundamental
de Mecánica de Materiales, lo cual se denomina Método Clásico, considerando cargas
estáticas y de fatiga; posteriormente, se hizo una aproximación al cálculo de la junta soldada
mediante el Análisis por Elementos Finitos (MEF), también considerando cargas estáticas y
de fatiga y, por último, se llevaron a cabo ensayos de tracción y fatiga con probetas soldadas
en ángulo. Se hace un estudio comparativo a fin de establecer una metodología actualizada
para el cálculo de la junta soldada en cuestión.
Se pone de relieve que existen factores utilizados para el cálculo de la vida a fatiga, tanto en el
Método Clásico como en el programa basado en MEF utilizado, como por ejemplo el factor
de reducción de la vida a fatiga, Kf, que son parámetros de ajuste por ambas metodologías y
deben ser obtenidos experimentalmente
2011-01-07T19:10:21ZVieira de Castro, FelipeSe realizó el estudio del comportamiento mecánico de una unión soldada en “T” con láminas
de acero UNE F1 utilizando electrodos revestidos AWS E-6013 con la finalidad de realizar un
aporte en referencia a los procedimientos de cálculo de ésta. Para ello, en primer lugar, se
efectuaron cálculos de interés con la finalidad de obtener la resistencia máxima de la junta
soldada y la magnitud de los esfuerzos utilizando fórmulas obtenidas de la teoría fundamental
de Mecánica de Materiales, lo cual se denomina Método Clásico, considerando cargas
estáticas y de fatiga; posteriormente, se hizo una aproximación al cálculo de la junta soldada
mediante el Análisis por Elementos Finitos (MEF), también considerando cargas estáticas y
de fatiga y, por último, se llevaron a cabo ensayos de tracción y fatiga con probetas soldadas
en ángulo. Se hace un estudio comparativo a fin de establecer una metodología actualizada
para el cálculo de la junta soldada en cuestión.
Se pone de relieve que existen factores utilizados para el cálculo de la vida a fatiga, tanto en el
Método Clásico como en el programa basado en MEF utilizado, como por ejemplo el factor
de reducción de la vida a fatiga, Kf, que son parámetros de ajuste por ambas metodologías y
deben ser obtenidos experimentalmenteApplication of reverse engineering concepts to compressed air tank
http://hdl.handle.net/2099.1/10742
Application of reverse engineering concepts to compressed air tank
Gilles, Guedia Guemo
This study, application of reverse engineering concepts to a compressed air tank, leads us to
calculate tank shell in static and fatigue, by using of formulas and software. Furthermore,
unsatisfying results from basics formulas of cylindrical and spherical shell, lead us to use
standards methods: ASME code and Indian standards to design torispherical head tank. Then
obtained results showed that, design a tank with torispherical head by ASME code is more
safety than Indian standards. It was proved that, Indian standards is the most economic,
because the life consumption of tank is only 3,8 % against 0,73% by ASME code.
However, those two methods showed that, the stress in knuckle is superior to admissible
strength in case of testing pressure (design pressure), but inferior with maximum operating
pressure. This explains the using of ring to reinforce the knuckle in some case.
2011-01-07T18:33:00ZGilles, Guedia GuemoThis study, application of reverse engineering concepts to a compressed air tank, leads us to
calculate tank shell in static and fatigue, by using of formulas and software. Furthermore,
unsatisfying results from basics formulas of cylindrical and spherical shell, lead us to use
standards methods: ASME code and Indian standards to design torispherical head tank. Then
obtained results showed that, design a tank with torispherical head by ASME code is more
safety than Indian standards. It was proved that, Indian standards is the most economic,
because the life consumption of tank is only 3,8 % against 0,73% by ASME code.
However, those two methods showed that, the stress in knuckle is superior to admissible
strength in case of testing pressure (design pressure), but inferior with maximum operating
pressure. This explains the using of ring to reinforce the knuckle in some case.Practical issue for a new identification method of Hammerstein system
http://hdl.handle.net/2099.1/10589
Practical issue for a new identification method of Hammerstein system
Huy Dang, Bui
The Hammerstein and Wiener models are nonlinear representations od systems composed by the coupling of a static nonlinearity N and a linear system L in the form N-L (Hammerstein) and L-N (Wiener). Although the forms are very simple, these models still represent many real life processes such as mechanical systems, chemical processes, electrical and electronic systems, etc. The problem of identifying the static nonlinearity and linear system is a tough but interesting and important task, which has attracted a lot of research interest. It has been studied in the available literature either for Hammerstein or Wiener systems, and either in a discrete-time or continuous-time setting. The results of these researches have been useful and widely applied in automatic and control industry.
Our project in fact involves in a new technique that was recently proposed [1]. This paper proposed a unified framework for the identification of both systems which are valid for single input single output (SISO) and multi inputs multi outputs (MIMO) systems, and without any particular structure for the static nonlinearity. This algorithm has been proven theoretically but it is necessary for such a verification of its characteristics compared with other existing algorithms.
The objective of this project is to discuss some practical aspects of implementation of this algorithm when applied to a simple example Hammerstein model. Then, this model is modified to represent a real life Wind Turbine Model [4]. The identification technique is also modified accordingly, and numerical simulations are carried out to validate this technique. The project is open-ended and the may be further developed with the existence of noise and even some more complicated Hammerstein models.
2010-12-20T17:12:05ZHuy Dang, BuiThe Hammerstein and Wiener models are nonlinear representations od systems composed by the coupling of a static nonlinearity N and a linear system L in the form N-L (Hammerstein) and L-N (Wiener). Although the forms are very simple, these models still represent many real life processes such as mechanical systems, chemical processes, electrical and electronic systems, etc. The problem of identifying the static nonlinearity and linear system is a tough but interesting and important task, which has attracted a lot of research interest. It has been studied in the available literature either for Hammerstein or Wiener systems, and either in a discrete-time or continuous-time setting. The results of these researches have been useful and widely applied in automatic and control industry.
Our project in fact involves in a new technique that was recently proposed [1]. This paper proposed a unified framework for the identification of both systems which are valid for single input single output (SISO) and multi inputs multi outputs (MIMO) systems, and without any particular structure for the static nonlinearity. This algorithm has been proven theoretically but it is necessary for such a verification of its characteristics compared with other existing algorithms.
The objective of this project is to discuss some practical aspects of implementation of this algorithm when applied to a simple example Hammerstein model. Then, this model is modified to represent a real life Wind Turbine Model [4]. The identification technique is also modified accordingly, and numerical simulations are carried out to validate this technique. The project is open-ended and the may be further developed with the existence of noise and even some more complicated Hammerstein models.Design of the manufacturing process of a reduction gear
http://hdl.handle.net/2099.1/10569
Design of the manufacturing process of a reduction gear
Tchoudi, William
The purpose of this project entitled “Design of the manufacturing process of a reduction gear”
is to design a manufacturing process in order to produce 20000 units of a reduction gear per
year. It is enrolled for a forecast of 5 years.
As the product involves public users, therefore it was mandatory to obtain good quality of
part. Taking into account today’s highly competitive economic environment, it was also
necessary to ensure the economic viability of the project, and thus profitability.
For achieving that, different steps have been followed. The first one was the definition of a
manufacturing strategy, which consists of deciding, for each part, which kind of operation is
done, either internally or externally (outsourcing manufacturing), according to criteria such as
surface finish of parts, mechanical properties, and the cost of rough parts.
Afterwards, an advanced planning of each cycle phase was prepared. In this second step,
the choice of the most convenient process and machine tool, tools, cutting conditions,
maximum power of the spindle, machining times and minimal production costs were defined.
The cycle and phase sheets were then provided for each machined part with related
explaining drawings.
In order to avoid waste times, a definition of the workshop organization machine tools and
layout was done.
Calculation of economical viability has ensured the feasibility and the profitability of the
manufacturing process.
As a conclusion, a comprehensive manufacturing process has been defined taking into
account both quality and economic requirements.
2010-12-16T19:52:33ZTchoudi, WilliamThe purpose of this project entitled “Design of the manufacturing process of a reduction gear”
is to design a manufacturing process in order to produce 20000 units of a reduction gear per
year. It is enrolled for a forecast of 5 years.
As the product involves public users, therefore it was mandatory to obtain good quality of
part. Taking into account today’s highly competitive economic environment, it was also
necessary to ensure the economic viability of the project, and thus profitability.
For achieving that, different steps have been followed. The first one was the definition of a
manufacturing strategy, which consists of deciding, for each part, which kind of operation is
done, either internally or externally (outsourcing manufacturing), according to criteria such as
surface finish of parts, mechanical properties, and the cost of rough parts.
Afterwards, an advanced planning of each cycle phase was prepared. In this second step,
the choice of the most convenient process and machine tool, tools, cutting conditions,
maximum power of the spindle, machining times and minimal production costs were defined.
The cycle and phase sheets were then provided for each machined part with related
explaining drawings.
In order to avoid waste times, a definition of the workshop organization machine tools and
layout was done.
Calculation of economical viability has ensured the feasibility and the profitability of the
manufacturing process.
As a conclusion, a comprehensive manufacturing process has been defined taking into
account both quality and economic requirements.Mechanisms and strategies of power regulation in wind turbines
http://hdl.handle.net/2099.1/10535
Mechanisms and strategies of power regulation in wind turbines
Dasey, Michael Noel
The modelling and simulation of wind turbines is becoming more important as the penetration levels of wind turbines are increasing. This means that the effects the various types of wind turbines have on electrical grids and possible ways to control power output quality should be understood in order to facilitate wind energy expansion and to ensure minimal negative effects on local and wider area grids.
Chapter 2 provides a literature review of the current research related to constant speed turbines (both passive and active stall) and the variable speed DFIG turbine. Although the latter is not examined further in this thesis, it is mentioned to provide a point of comparison with the constant speed technology. The literature review also enabled to results of previous simulation and the results of this thesis to be successfully validated.
The Chapter 3 deals with the constant speed turbine as a steady state simulation. The steady state simulation showed that the chosen turbine characteristic would have a power generation design point of 2MW, and was designed for optimum output at an average wind velocity of 15m/s. The steady state simulations also showed that effect a change in frequency would have on the power output.
Comparing the simulations of the passive stall of Chapter 4 and the active stall control of Chapter 5 it was shown that with the addition of pitch control there was still a significant overshoot of design output power of 0.06-0.08p.u, along with a high frequency variation of 0.05p.u. While the pitch actuators were engaged, this did not provide any significant reduction in design point overshoot or turbine behaviour
The advantage of the active stall control was explored in Chapter 6, demonstrating the active stall control turbine can be used successfully in providing primary, secondary and high frequency support. A new set point could be reached within the required 10sec, and the output remained relatively steady. Though this power output is of course still reliant, and varies slightly depending on the wind velocity behaviour.
2010-12-15T17:44:17ZDasey, Michael NoelThe modelling and simulation of wind turbines is becoming more important as the penetration levels of wind turbines are increasing. This means that the effects the various types of wind turbines have on electrical grids and possible ways to control power output quality should be understood in order to facilitate wind energy expansion and to ensure minimal negative effects on local and wider area grids.
Chapter 2 provides a literature review of the current research related to constant speed turbines (both passive and active stall) and the variable speed DFIG turbine. Although the latter is not examined further in this thesis, it is mentioned to provide a point of comparison with the constant speed technology. The literature review also enabled to results of previous simulation and the results of this thesis to be successfully validated.
The Chapter 3 deals with the constant speed turbine as a steady state simulation. The steady state simulation showed that the chosen turbine characteristic would have a power generation design point of 2MW, and was designed for optimum output at an average wind velocity of 15m/s. The steady state simulations also showed that effect a change in frequency would have on the power output.
Comparing the simulations of the passive stall of Chapter 4 and the active stall control of Chapter 5 it was shown that with the addition of pitch control there was still a significant overshoot of design output power of 0.06-0.08p.u, along with a high frequency variation of 0.05p.u. While the pitch actuators were engaged, this did not provide any significant reduction in design point overshoot or turbine behaviour
The advantage of the active stall control was explored in Chapter 6, demonstrating the active stall control turbine can be used successfully in providing primary, secondary and high frequency support. A new set point could be reached within the required 10sec, and the output remained relatively steady. Though this power output is of course still reliant, and varies slightly depending on the wind velocity behaviour.