Dissertations / Theses on the topic 'Flow control system'
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Yan, Li. "On the traffic flow control system." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B39431174.
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Yan, Li, and 顏理. "On the traffic flow control system." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B39431174.
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Bornman, Waldo. "Improved mine cooling system performance through the control of auxiliary systems / W. Bornman." Thesis, North-West University, 2012. http://hdl.handle.net/10394/9105.
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Industrial and mining sectors are amongst the largest single energy consumers in South
Africa, making them a primary focus for implementing energy saving initiatives.
Refrigeration systems on mines are responsible for consuming up to25 % of the electrical
energy consumption on a typical South African deep level mine. Ample opportunities to
reduce the energy consumption of these systems exists, as many of the current systems rely
on old technology and function under partial or inadequate control management.
In compiling this thesis, various energy saving strategies on deep level mines were
investigated. In specific, the effects of controlling and improving the cooling auxiliaries.
Scenarios were investigated and simulated, where after an optimum solution was
implemented. Implementations, such as the ones covered in this dissertation, form part of the
IDM (Integrated Demand Management) energy efficiency incentive introduced by Eskom,
where funding is made available based on actual power saving; ensuring that the projects will
be financially viable to the clients.
Reduced electrical energy consumption realised from the abovementioned projects were
measured, captured and compared to the consumption before project implementation to
determine the achieved savings. Savings of up to 30 % of the plant installed capacity were
realised, providing average savings of up to 2.3 MW per day.Thesis (MIng (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2013
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Thiron, Benjamin. "Global Control of a Life Support System : Flow control and optimisation." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278509.
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The subject of study of this degree project is the MELiSSA (Micro-Ecological Life Support System Alternative) Life SupportSystem (LSS) developed by the European Space Agency (ESA). The MELiSSA LSS aims to recycle human wastes into O2,water and food for the crew of a spacecraft. The purpose of this project is to model and study the MELiSSA LSS, in order todesign a global control system that ensures the survival of the crew while minimizing the resources needed. The MELiSSA LSSis composed of 4 biochemical reactors, called the compartments, controlled locally. A model of all the possible critical flowsexchanged by the compartments is built from a functional point of view. These flows are controlled using the Predictive FunctionalControl (PFC) method.This study confirms that the MELiSSA LSS can function properly but requires external resources. In addition, the study showsthat by using the right external resources, the MELiSSA LSS can achieve its goal. The objective of the MELiSSA LSS is toproduce 100% of the O2, 90% of the water and about 40% of the food the crew needs to survive. With an additional amountof ammonia (NH3), nitric acid (HNO3) and carbon dioxide (CO2), the LSS reaches a production of 100% of the O2, more than100% of the water and between 45 and 50% of the food the crew needs. Moreover, when its operation is optimized, it reducesthe mass to carry per astronaut per day to less than 50% of the mass needed without optimization. This is about 12% of themass needed when there is no recycling system. The model built for this study can also be used as a dimensioning model or anenvironment and contextualization model for the development and testing of the different compartments.Ämnet för det här examensprojektet är MELiSSA (Micro-Ecological Life Support System Alternative) Life Support System (LS som utvecklats av Europeiska rymdorganisationen (ESA). MELiSSA LSS ämnar att återvinna mänskligt avfall till syre (O2), vatten och mat för en rymdbesättning. Examensarbetet syftar att modellera och studera MELiSSA LSS för att utforma ett globalt kontrollsystem som säkerställer besättningens överlevnad samtidigt som de nödvändiga resurserna minimeras. MELiSSA LSS består av fyra biokemiska reaktorer, kallat “utrymmena”, som kontrolleras lokalt. En modell av all tänkbara kritiska flöden som utbyts mellan utrymmena är byggd utifrån ett funtionellt perspektiv. Flödena kontrolleras med Predictive Functional Control (PFC) metoden.Studien bekräftar att MELiSSA LSS kan fungera korrekt men kräver externa resurser. Dessutom visar studien att MELiSSA LSS kan upfylla sitt mål givet rätt externa resurser. Målet med MELiSSA LSSS är att producera 100% av O2, mer än 90% av vattnet och 40% av maten som besättningen behöver för att överleva. Med en ytterligare mängd ammoniak (NH3), salpetersyra (HNO3) och koldioxid (CO2), når LSS en produktion på 100% av O2, mer än 100% av vattnet samt mellan 45 och 50% av maten som besättningen behöver. Vid optimering reduceras massan som behöver bäras per astronaut per dag till mindre än 50% av massan som behövs utan optimering. Det motsvarar ungefär 12% av massan som behövs utan ett återvinningssystem. Modellen na studie kan även användas som dimensioneringsmodell eller som en miljö och kontextualiseringsmodellr utveckling och testning av de olika utrymmena.
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Mohd, Tahir Muhammad. "Instrumentation and control and industrial computer systems: Pumps and flow control valves for universal water system." Thesis, Mohd Tahir, Muhammad (2018) Instrumentation and control and industrial computer systems: Pumps and flow control valves for universal water system. Honours thesis, Murdoch University, 2018. https://researchrepository.murdoch.edu.au/id/eprint/41920/.
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The main purpose of this thesis is to investigate pump and flow control valve on Universal Water System (UWS) located in Murdoch University by experiment to obtain their performance characteristics and other behaviours.
Overall, USW equipped with 9 pumps with various types that can be categorised into 3 main types which are centrifugal, positive displacement and air operated diaphragm pumps. Besides that, UWS is installed with 35 valves. However, this project only focuses on 7 pumps and 3 flow control valves.
To obtain the best result, experiment held in this project consists 3 main phases, experimental setup, data collecting and data evaluation. Every detail regarding the setup, method and calculation applied in this project are explained in this report.
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Nilsson, Joel. "Embedded Control System for a High Precision Flow Meter." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-49840.
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This degree project has been conducted to study flow meters and develop firmware for EC Instrument’s Reciflow. Flow rate is the volume of a fluid or mass of a substance which passes through a surface per time unit. Conversion can be made between volumetric and mass flow rate if the gas density is known. A market survey showed that Coriolis and thermal mass flow meters and positive displacement (volumetric) flow meters, as the Reciflow, are the most common kinds. The Reciflow consist of a system-on-board and a displacement meter with an optical encoder. The displacement meter is a cylinder with a piston within and valves at the ends. The firmware controls the valves so that the piston can reciprocate. The components of the Reciflow affects the accuracy and it is estimated to ±0;025 % for non-normalized and ±0;2 %for normalized flow. It is measured under normal conditions to be ±0;2 %normalized, relative to a reference. Further experiments must be performed to verify the accuracy and also the precision. The actual measurement of flow rate and volume is made with the encoder: as a difference in time between signal edges and the total number of edges accounted for. Data with random noise is filtered with moving average filters and heuristic methods is used to handle static noise. Serial communication has been implemented for on- and off-board uses. A user can interact with the instrument using either a touchscreen or a terminal.
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Kreikebaum, Frank Karl. "Control of transmission system power flows." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50392.
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Power flow (PF) control can increase the utilization of the transmission system and connect lower cost generation with load. While PF controllers have demonstrated the ability to realize dynamic PF control for more than 25 years, PF control has been sparsely implemented.
This research re-examines PF control in light of the recent development of fractionally-rated PF controllers and the incremental power flow (IPF) control concept. IPF control is the transfer of an incremental quantity of power from a specified source bus to specified destination bus along a specified path without influencing power flows on circuits outside of the path.
The objectives of the research are to develop power system operation and planning methods compatible with IPF control, test the technical viability of IPF control, develop transmission planning frameworks leveraging PF and IPF control, develop power system operation and planning tools compatible with PF control, and quantify the impacts of PF and IPF control on multi-decade transmission planning.
The results suggest that planning and operation of the power system are feasible with PF controllers and may lead to cost savings. The proposed planning frameworks may incent transmission investment and be compatible with the existing transmission planning process. If the results of the planning tool demonstration scale to the national level, the annual savings in electricity expenditures would be $13 billion per year (2010$). The proposed incremental packetized energy concept may facilitate a reduction in the environmental impact of energy consumption and lead to additional cost savings.
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Tomashevskyi, Roman, Viacheslav Kulichenko, and Nikolay Mahonin. "System for Flow Rate Regulation with Pulse-Width Modulation." Thesis, Kyiv polytechnic institute, 2014. http://repository.kpi.kharkov.ua/handle/KhPI-Press/7880.
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In article describes the concept of the flow control system for ozone-oxygen mixture, using the principles of pulse-width modulation. The basic equation for calculation of the system measurement channel are given. Experimental studies of such air channel system and its performance characteristics are describes. The possibility of using flow control system ozone-oxygen mixture in medical ozone is shown.
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Sreenivasachar, Kannan. "Unified power flow controller, modeling, stability analysis, control strategy and control system design." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ60570.pdf.
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Mundy, David H. "Decentralised control flow : a computational model for distributed systems." Thesis, University of Newcastle Upon Tyne, 1988. http://hdl.handle.net/10443/2050.
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This thesis presents two sets of principles for the organisation of distributed computing systems. Details of models of computation based on these principles are together given, with proposals for programming languages based on each model of computation. The recursive control flow principles are based on the concept of recursive control flow computing system structuring. A recursive comprises a group of subordinate computing systems connected together by Each subordinate computing system may either be a communications medium. which a a computing system consists of a processing unit, memory some is itself a recursive component, and input/output devices, or computing components control flow system. The memory of all the computing systems within a recursive control flow computing subordinate system are arranged in a hierarchy. Using suitable addresses, any part of the hierarchy is accessible to any sequence of instructions which may be executed by the processing unit of a subordinate computing system. This rise to serious difficulties in the global accessibility gives understanding of programs written the meaning of in a programming language recursive control flow on the model of computation. based Reasoning about a particular program in isolation is difficult because of the potential interference between the execution different programs cannot be ignored . alternative principles, decentralised control flow, restrict the The accessibility of subordinate global the memory components of the computing The basis of the concept of objects forms the systems. principles. Information channels may flow along unnamed between instances of these objects, this being the only way in which one instance of an object may communicate with some other instance of an object. Reasoning particular program written in a programming language about a based on the decentralised control flow model of computation is easier since it is that there will be no interference between the guaranteed execution of different programs.
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Weigang, Li. "Knowledge-based system for air traffic flow management : timetable rescheduling and centralized flow control." Instituto Tecnológico de Aeronáutica, 1994. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=1711.
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Future air traffic management (ATM) systems have been identified as a matter of great significance for the evolution of future air navigation systems (FANS). As one function of ATM, Air Traffic Flow Management (ATFM) provides a service complementary to Air Traffic Control (ATC). In this research, a Knowledge-Based System (KBS) has been designed to try to solve the ATFM problem. For timetable rescheduling, the system attempts to modify airlines tiemtable to smooth traffic peaks at airports during rush-hours. For centralized flow control, the system works on-line to forecast the place, time and magnitude of the congestion and to take some actions to prevent this congestion. As an Artificial Intelligence language, Prolog was chosen for developing the prototype of the Knowledge-Based ATFM System. The research gives a conceptual description of the application of KBS (specially in Prolog) in the ATFM domain. Using this system, a study of the Brazilian ATFM systemincluding the main airports of the country has been done.
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Laird, Daniel T., and Jon Morgan. "Data Flow and Remote Control in the Telemetry Network System." International Foundation for Telemetering, 2009. http://hdl.handle.net/10150/606151.
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ITC/USA 2009 Conference Proceedings / The Forty-Fifth Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2009 / Riviera Hotel & Convention Center, Las Vegas, NevadaThe Central Test and Evaluation Investment Program (CTEIP) Integrated Network Enhanced Telemetry (iNET) program is currently developing new standards for wired-wireless local area networking (LAN-WLAN) using the Internet Protocol (IP), for use in telemetry (TM) channels, under the umbrella of the Telemetry Network System (TmNS). Some advantages of TmNS are real-time command and control of instrumentation, quick-look acquisition, data retransmission and recovery ('gapless TM' or 'PCM backfill'), data segmentation, etc. The iNET team is developing and evaluating prototypes, based on commercial 802.x and other technologies, in conjunction with Range Commander's Council (RCC) Inter-Range Instrumentation Group (IRIG) standards and standards developed under the iNET program.
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Fang, Yong Jie. "Dynamic and transient system control using fast acting quadrature boosters." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244084.
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Rydeman, Gustav. "Decision Support for Work Flow Control in a Warehouse Management System." Thesis, Uppsala University, Department of Information Technology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-112111.
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As volatility and customer demands increase, companies are simultaneously trying to reduce their logistic costs. Distribution centers are being forced to increase their agility and flexibility in order to rapidly execute on continuously evolving logistics plans. One proven way of gaining warehouse efficiency and create visibility into processes is through implementation of a Warehouse Management System (WMS) – a leverage technology that introduces automation in warehouse processes. With system directed task assignment work can be optimally balanced and distributed to available resources and auto-generate tasks with high quality. A critical aspect of this have shown to be prioritization of tasks in the dynamic terminal environment. To introduce a new work flow support into an existing organization requires changes in routines, roles and organization to harvest the real efficiency gains. In this report these problematics are applied to the distributing terminal of SCA Transforest, Tunadal, Sweden. A benchmarking study of a terminal in the same business, the Stora Enso terminal in Zeebrügge, Belgium, is the object of comparison. At the latter terminal system directed task assignment has been successfully implemented. Based on the findings from the benchmarking study and other research this report present important success factors as well as specific solutions to issues regarding automation, flexibility and process visibility - with the purpose to guide SCA Transforest in the future system development.
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Kotsbak, Marius Bjørnstad. "Microcontroller based fluid flow and image control system for biochemical analysis." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for teknisk kybernetikk, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18325.
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Jarle Kotsbak started started the company Kotsbak Consulting to test an idea he had of a method of sequencing DNA material, that is reading the contents of the string of genes in a DNA. The method is supposed to be much faster and cheaper than the methods that exist today. For the analysis equipment there are a lot of parts that need to be developed, and the most important ones in the first phases of experimentation is given as problems for this thesis.The analysis is going to take place in a relatively small reaction chamber where chemicals need to be automatically added and heated to the correct temperature. Then a high resolution image is going to be captured using a small image chip similar to those found inside digital cameras. As these have varying real time requirements, it is not possible to control from a ordinary PC. A microcontroller is needed to do the low level controls. Control of the experiments should be possible to set up from a PC connected to the equipment using a USB (Universal Serial Port) 2.0 port, which is also going to transfer the images captured to the PC for image and data analysis.Atmel AVR32 microcontroller was suggested for use, and it was not found that any of the requirements was not in theory possible to solve using this microcontroller, so it was the one used in all parts. It was evaluated if it was best to program the microcontroller directly without an operating system, but it was found that using Linux, which the evaluation boards of the microcontroller was shipped with, had so many advantages over the small and uncertain advantages of programming the microcontroller directly. so Linux was used in all parts. As most of the needed drivers for Linux were new or unreleased, a lot of time was spent learning how to compile the Linux kernel with those patches and finding out how to use the undocumented parts of the drivers, as well as extending the drivers to support the hardware and specification needed.The heating controller worked quite well after getting the connection to the sensors working, including estimation of the temperature inside the reaction chamber, which is the temperature that is going to be controlled, but can not be measured directly. If needed it is possible to tune the controller better for stricter requirements or change to a model based controller if needed and the parameters in the model can be found, which turned out to be hard.A nice solution to the flow control was found using a stepping motor that is able to push the piston in a syringe containing one of the chemical mixes in exact amounts, controlled by an external stepping motor driver chip, which was easy to get working, connected using I2C. The solution was at least as good and much easier to implement than the one suggested in the assignment, using valves and pressure measurements to estimate the amount flowing.It was shown that image capture of the required resolution, i.e. 2048 x 1536 and possibility for much higher, was possible using Linux and the hardware support for transferring images from image chips in the AVR32 microcontroller using kernel modules. The problem is that it was only working sometimes, so a little more debugging of the possible hardware/ software reason for this to be resolved, but it seems like it is only a small problem and not caused by any limitation in software or hardware.It was attempted to get the USB part working without running an O/S on the microcontroller, but it did not succeed, partly because of incomplete documentation of the USB hardware module in the AVR32. Then the available driver systems for USB slave equipment under Linux was studied and it was found that gadgetfs seemed most promising to use. The driver did though first not load, just giving a stacktrace. In a newer version of the Linux version for the development board, it did though load and it seemed like it was working. Further development of this part was not done because of much delay in the other parts, and the fact that choosing Linux as platform, as well as the image being buffered in RAM, allows to use ethernet to transport the images during testing until later product development stages.Overall most of the parts have been accomplished according to the specifications, although there was not too detailed practical testing of each part because of much time spent on solving problems, and the fact that many complex parts were outlined to be solved during the project. Solving the small problems left as described at the corresponding discussion chapters should, with small modifications/customization, make the practical solutions found usable for future prototypes of the product or for more experiments.
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OKUMA, Shigeru, Tatsuya SUZUKI, YoungWoo KIM, and Tatsuya KATO. "Model Predictive Control of Traffic Flow Based on Hybrid System Modeling." Institute of Electronics, Information and Communication Engineers, 2005. http://hdl.handle.net/2237/14988.
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Barreto, Hugo. "PARALLEL SIMULATION FOR CONCURRENT DEVELOPMENT OFMANUFACTURING FLOW AND ITS CONTROL SYSTEM." Thesis, KTH, Industriell produktion, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-160268.
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Companies nowadays must innovate to achieve or retain a competitive position in the market. In manufacturing companies the introduction of a new product often requires design of the manufacturing system itself, which greatly increases product development time. Manufacturing system development has been relying lately on simulation models, which decrease the need for hardware testing, but the engineering applications needed for development are isolated. Concurrent engineering has found applications in the interface between the product and its manufacturing system. However, little has been researched in the concurrent development of the several steps of manufacturing system. This report presents a communications method to connect two simulation models in parallel, in two different computers, in what can be called a distributed simulation. One of the models is the flowsimulation modelled as a discrete event simulation (DES), while the other model represents the controlsystems modelled as finite state machines (FSM). Both models run in Matlab/Simulink. This concept allows two developers to work simultaneously in otherwise sequential development tasks, and get validation of their implementation while developing. The communication between the systems is achieved with the OPC protocol, an established technology in networked control systems (NCS). With a simple example model, the system is able to run in parallel, and the effectiveness of the parallel development was observed as the model was adjusted to its distributed format. The main difficulties found during implementation are related with the DCOM configuration necessary for the OPC technology and the setup of data exchange modes (synchronous/asynchronous). The distributed simulation requires real-time execution to run properly and reliably, which results in longer simulation times than single platform simulation. Finite State Machines were also successfully used to model control systems. This technique simplifies development and debugging due to its formal structure and visual interface. Overall, the results of this implementation offer good possibilities of further studies in the application of distributed simulation in concurrent development. This report also lays the path for more complexsimulation using this concept, both in the models used and the number of computers connected in parallel.Företag måste idag vara innovativa för att uppnå eller behålla en konkurrenskraftig position på marknaden. I tillverkande företag kräver nya produkter ofta design av tillverkningssystemet i sig, vilket i hög grad ökar produktutvecklingstiden. Tillverkningssystemutveckling har på sistone förlitat sig på simuleringsmodeller, vilket minskar behovet av att testa hårdvaran. Däremot är de tekniska mjukvarorna som behövs för utveckling isolerade. Concurrent engineering metoder har funnit applikationer vid koppling mellan produkten och produktionssystemet. Däremot har man forskat för lite i samtidig utvecklingen i de olika stegen i tillverkningssystemet. Den här rapporten presenterar en kommunikationsmetod för att ansluta två simuleringsmodeller parallellt i två olika datorer, i vad som kan kallas en distribuerad simulering. Ena modellen är den flödessimuleringen vilken modelleras som en diskret-händelsestyrd simulering (DES), medan den andra modellen är det kontrollsystemet som modelleras som Finit Tillståndsmaskin (FSM). Båda modeller körs i Matlab/Simulink. Det här innebär att två utvecklare kan arbeta samtidigt med utvecklingsuppgifterna i stället för att behöva jobba i sekvens, och få validering samtidigt som utvecklingen sker. Kommunikationen mellan systemen uppnås med den OPC specifikation, en etablerad teknik i nätverkskontrollsystem (NCS). Med en enkel exempel modell, körs systemet parallellt. Och effektiviteten observeras medan modellen anpassas till det distribuerade formatet. De största svårigheterna med implementering grundar sig i DCOM-konfiguration som är grundläggande för OPC teknik och installationen av datautbyteslägen (synkron / asynkron). Den distribuerade simuleringen kräver körning i realtid så det kan fungera korrekt och pålitligt, vilket resulterar i längre simuleringstider än en enkel plattform simulering. Finit Tillståndsmaskiner användes också med framgång för att modellera kontrollsystem. Denna tekniken förenklar utveckling och problemlösning på grund av sina formell struktur och visuell gränssnitt. Resultatet av det här projektet visar goda möjligheter till fortsatta studier i tillämpningen av distribueradsimulering i samtidig (concurrent) utveckling. Rapporten ger också goda förutsättningar för komplexare simuleringar med detta koncept, både i de modeller som användes och antalet datorer som kan anslutnas parallellt.
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Elgayar, Ibrahim. "Mathematical modelling, flight control system design and air flow control investigation for low speed UAVs." Thesis, City University London, 2013. http://openaccess.city.ac.uk/2737/.
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The demand for unmanned aerial vehicles (UAVs) has increased dramatically in the last decade from reconnaissance missions to attack roles. As their missions become more complex, advances in endurance and manoeuvrability become crucial. Due to the advances in material fabrication, wing morphing can be seen as an ideal solution for UAVs to provide improvements by overcoming the weight drawback. This thesis investigates the area of aircraft design and simulation for low speed UAVs looking at performance enhancements techniques for low speed UAVs, and their effects on the aerodynamic capabilities of the wing. The focus is on both suitable control design and wing morphing techniques based on current research findings. The low speed UAV X-RAE1 is used as the test bed for this investigation and is initially analytically presented as three dimensional body where the equations relate to the forces and moments acting on the UAV. A linearised model for straight flight at different velocities is implemented and validated against a non-linear model. Simulations showed the X-RAE1 to have acceptable stability properties over the design operating range. Control design techniques, linear quadratic regulators (LQR) and H-infinity optimisation with Loop Shaping Design Procedure (LSDP), are used to design simple control schemes for linearised longitudinal model of the X-RAE1 UAV at different velocities. The effectiveness and limitations of the two design methods show that both designs are very fast, with settling times 2-3 seconds in the height response and remarkably low variation of the results at different velocities. Computational fluid dynamics is then used to investigate and simulate the impact of introducing smart effector arrays on a UAV. The smart effector array produces a form of active flow control by providing localised flow field changes. These induced changes have direct impact on the aerodynamic forces and showed a substantial increase of lift at low angles of attack. There was also a significant increase to the lift to drag ratio at high angles of attack which resulted to a delay in stall.
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Varon, Eliott. "Contrôle réactif d'écoulements décollés à l'aide de PIV temps réel." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLET008/document.
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Les écoulements décollés sont omniprésents dans la nature comme dans les écoulements industriels (aérodynamique externe des véhicules, des bâtiments, écoulements autour d’aubes de turbines, aérodynamique interne dans des tuyaux...) où ils sont en général sources de nuisances (vibrations, bruit aéroacousitque, forces de traînée ou de portance). Les enjeux associés à la compréhension et à la maîtrise de tels écoulements, caractérisés par une bulle de recirculation, sont donc considérables.Un capteur "visuel" non invasif développé au laboratoire PMMH est d'abord amélioré afin d'accéder en temps réel aux champs de vitesses - et à leurs grandeurs dérivées - des écoulements rencontrés en soufflerie industrielle. Basé sur un algorithme de flot optique issu de la vision par ordinateur, cette approche expérimentale novatrice permet de faciliter les études paramétriques et peut être implémenté dans des boucles de contrôle réactif.Ensuite, les mesures obtenues pour un écoulement sur une plaque plane sont analysées dans le cadre de l'identification de système. Un modèle d’ordre réduit est alors construit par apprentissage, permettant de prédire la dynamique de la transition de la couche limite laminaire vers la turbulence.Enfin, le sillage pleinement turbulent derrière une géométrie modélisant une voiture simplifiée est caractérisé, de façon classique et en tant que système dynamique. Différentes modifications de l'écoulement à l'aide de micro-jets sont testées. Une loi de contrôle réactif consistant à suivre et forcer la recirculation est mise en œuvre avec succèsSeparated flows are ubiquitous in nature and industrial systems, such as diffusers, airfoils, air conditioning plants, moving vehicles... As the separation can strongly influence the performances of such devices, investigating their dynamics and their control is of great interest.A visual sensor developed at PMMH laboratory is first improved to measure in real time the velocity fields and its derived values for flows available in wind tunnels. Based on an optical flow algorithm from the computer vision domain, this new experimental approach makes easier parametric studies and may be used in closed-loop controls.The dynamics of the flow over a flat plate are then investigated. A system identification method - the dynamic observer - is successfully implemented to build a reduced-order model of the transient flow, which captures and predicts well the instabilities generated.Finally, the fully turbulent wake of the square-back Ahmed body is described. Dynamical system tools are applied to characterize it. Using continuous and pulsed micro-jets, different forcing strategies are analyzed. An opposition closed-loop control is implemented, tracking and driving the recirculation
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Skvorchevsky, A. Y. "ELS capacity control system for axial-piston pumps." Thesis, Національний технічний університет "Харківський політехнічний інститут", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/46920.
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Juillet, Fabien. "Control of convection-dominated flows." Palaiseau, Ecole polytechnique, 2013. http://pastel.archives-ouvertes.fr/docs/01/00/94/63/PDF/PhD_Juillet_Fabien.pdf.
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Cette thèse s'intéresse à la mise en œuvre d'une technique de contrôle d'écoulements, d'un point de vue à la fois numérique et expérimental. L'objectif de cette technique est la réduction de perturbations au sein d'écoulements dominés par la convection. Dans ce but, trois aspects sont développés au sein d'un première partie. On observe tout d'abord que dans de tels systèmes l'information voyage essentiellement vers l'aval. Pour cette raison les perturbations doivent être mesurées le plus tôt possible, en plaçant les capteurs en amont. Cette idée intuitive est étudiée quantitativement en introduisant le concept de " longueur de visibilité ". Ensuite, une description de l'écoulement est obtenue à l'aide de technique d'identification de systèmes. Ces outils présentent l'avantage de construire des modèles en se fondant uniquement sur des données accessibles au sein d'une expérience. Enfin, une approche de contrôle du type feed-forward étant particulièrement appropriée pour ces écoulements, une comparaison théorique et numérique avec la théorie classique LQG (Linear Quadratic Gaussian) est menée. Dans une seconde partie, ces trois aspects sont pris en compte dans une procédure d'identification et de contrôle qui est simplifiée de manière à faciliter une mise en place expérimentale. En particulier, les réponses impulsionnelles du système sont identifiées puis utilisées directement dans le calcul de la loi de contrôle. Cette technique repose alors uniquement sur de simples minimisations par moindres carrés et présente l'avantage d'être fondée sur des quantités aux interprétations physiques claires, telles que des vitesses de convection ou des fréquences caractéristiques. Enfin, dans une dernière partie, la procédure est appliquée expérimentalement au contrôle de perturbations dans une écoulement de Poiseuille à Re =870. Dans cette expérience, l'amplitude du signal mesuré par un capteur objectif a pu être réduite de 45%In this thesis, a flow control procedure is developed numerically and is then implemented experimentally. The purpose of this procedure is to reduce the amplitude of perturbations in convection dominated flows. To design such a technique three aspects are analyzed in a first part. Since information in convection-dominated flows essentially travel downstream, incoming perturbations are better described by placing sensors upstream. This intuitive idea is studied quantitatively by introducing the concept of visibility length. In addition, a description of the flow dynamics is obtained using system identification techniques. These tools have the advantage of providing models based solely on experimentally accessible data and are therefore directly applicable to real flows. Finally, a feed-forward control approach is found to be most appropriate and a comparison with the classical linear quadratic gaussian technique is presented from numerical and theoretical point of views. In a second part, these three aspects are then taken into account in the design of a feed-forward identification and control procedure, which is then simplified to be more amenable to practical implementations in experiments. In particular, the system impulse responses are first identified, and are then directly used for the computation of the control law. Hence, the technique only relies on simple least-squares minimizations and has the advantage of manipulating quantities that have clear physical meanings, such as perturbation convective speeds and characteristic frequencies. Thus, in a last part, the control procedure is applied experimentally to the quenching of natural disturbances in a plane channel flow at Re = 870. Results show that the magnitude of the signal recorded by the objective sensor can be reduced by up to 45%
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Sheu, Hsin-Teng. "A coordinated decentralized flow and routing control algorithm for an automated highway system /." The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu148758564557836.
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Björkman, Carl. "Computing component specifications from global system requirements." Thesis, KTH, Teoretisk datalogi, TCS, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-210843.
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If we have a program with strict control flow security requirements and want to ensure system requirements by verifying properties of said program, but part of the code base is in the form of a plug-in or third party library which we do not have access to at the time of verification, the procedure presented in this thesis can be used to generate the requirements needed for the plug-ins or third party libraries that they would have to fulfil in order for the final product to pass the given system requirements. This thesis builds upon a transformation procedure that turns control flow properties of a behavioural form into a structural form. The control flow properties focus purely on control flow in the sense that they abstract away any kind of program data and target only call and return events. By behavioural properties we refer to properties regarding execution behaviour and by structural properties to properties regarding sequences of instructions in the source code or object code. The result presented in this thesis takes this transformation procedure one step further and assume that some methods (or functions or procedures, depending on the programming language) are given in the form of models called flow graph, while the remaining methods are left unspecified. The output then becomes a set of structural constraints for the unspecified methods, which they must adhere to in order for any completion of the partial flow graph to satisfy the behavioural formula.Om vi har ett program med strikta kontrollflödeskrav och vill garantera att vissa systemkrav uppfylls genom att verifiera formella egenskaper av detta program, samtidigt som en del av kodbasen är i form av ett plug-in eller tredjeparts-bibliotek som vi inte har tillgång till vid verifieringen, så kan proceduren som presenteras i detta examensarbete användas för att generera de systemkrav som de plug-in eller tredjeparts-bibliotek behöver uppfylla för att slutprodukten ska passera de givna systemkraven. Detta examensarbete bygger på en transformationsprocedur som omvandlar kontrollflödesegenskaper på en beteendemässig form till en strukturell form. Kontrollflödes-egenskaperna fokuserar uteslutande på kontrollflöden i den meningen att de abstraherar bort all form av programdata och berör enbart anrop- och retur-händelser. Med beteendemässiga egenskaper syftar vi på egenskaper som berör exekverings-beteende och med strukturella egenskaper syftar vi på egenskaper som berör ordningen på instruktionerna i källkoden eller objektkoden. Resultatet i detta examensarbete tar denna transformationsprocedur ett steg längre och antar att vissa metoder (eller funktioner eller procedurer beroende på programmeringsspråk) är redan givna i formen av modeller som kallas flödesgrafer, medan resten av metoderna fortfarande är ospecificerade. Utdata blir då en mängd av strukturella restriktioner för de ospecificerade metoderna, som de måste följa för att en fulländning av den partiella flödesgrafen ska satisfiera den beteendemässiga formeln.
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Kama, O. I. "Computer system for operational control of the optimal flow of the technological process." Master's thesis, Sumy State University, 2021. https://essuir.sumdu.edu.ua/handle/123456789/86924.
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Создана компьютерная система, управляющая оптимальным течением технологического процесса, показывающая места перекосов.A computer system which controls the optimal flow of the technological process was created showing places of distortion.
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Au, Lai Piu. "A simulation study of dynamic customer flow control in multi-site service system /." View Abstract or Full-Text, 2002. http://library.ust.hk/cgi/db/thesis.pl?IEEM%202002%20AU.
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Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2002.Includes bibliographical references (leaves 106-108). Also available in electronic version. Access restricted to campus users.
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Song, Yang. "Design of secondary voltage and stability controls with multiple control objectives." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29714.
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Thesis (Ph.D)--Electrical and Computer Engineering, Georgia Institute of Technology, 2009.Committee Chair: Begovic, Miroslav; Committee Member: Deng, Shijie; Committee Member: Divan, Deepakraj; Committee Member: Harley, Ronald; Committee Member: Lambert, Frank; Committee Member: Shamma, Jeff. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Vacca, Andrea, and Ram Sudarsan Devendran. "A Flow Control System for a Novel Concept of Variable Delivery External Gear Pump." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-200144.
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This paper describes a novel concept for a low cost variable delivery external gear pump (VD-EGP). The proposed VD-EGP is based on the realization of a variable timing for the connections of the internal displacement chambers with the inlet and outlet ports. With respect to a standard EGP, an additional element (slider) is used along with asymmetric gears to realize the variable timing principle. Previously performed tests confirmed the validity of the concept, for a design capable of varing the flow in the 65%-100% range. Although the VD-EGP concept is suitable for various flow control system typologies (manual, electro-actuated, hydraulically flow- or pressure- compensated), this paper particularly details the design and the test results for a prototype that includes both a manual flow control system and a pressure compensator. Flow vs pressure and volumetric efficiency curves are discussed along with transient (outlet flow fluctuation) features of the VD-EGP.
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Jaworski, P. "Cloud computing based adaptive traffic control and management." Thesis, Coventry University, 2013. http://curve.coventry.ac.uk/open/items/d63ba84e-bd0c-4e00-8242-310dbbaa3b92/1.
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Recent years have shown a growing concern over increasing traffic volume worldwide. The insufficient road capacity and the resulting congestions have become major problems in many urban areas. Congestions negatively impact the economy, the environment and the health of the population as well as the drivers satisfaction. Current solutions to this topical and timely problem rely on the exploitation of Intelligent Transportation Systems (ITS) technologies. ITS urban traffic management involves the collection and processing of a large amount of geographically distributed information to control distributed infrastructure and individual vehicles. The distributed nature of the problem prompted the development of a novel, scalable ITS-Cloud platform. The ITS-Cloud organises the processing and manages distributed data sources to provide traffic management methods with more accurate information about the state of the traffic. A new approach to service allocation, derived from the existing cloud and grid computing approaches, was created to address the unique needs of ITS traffic management. The ITS-Cloud hosts the collection of software services that form the Cloud based Traffic Management System (CTMS). CTMS combines intersection control algorithms with intersection approach advices to the vehicles and dynamic routing. The CTMS contains a novel Two-Step traffic management method that relies on the ITS-Cloud to deliver a detailed traffic simulation image and integrates an adaptive intersection control algorithm with a microscopic prediction mechanism. It is the first method able to perform simultaneous adaptive intersection control and intersection approach optimization. The Two-Step method builds on a novel pressure based adaptive intersection control algorithm as well as two new traffic prediction schemes. The developed traffic management system was evaluated using a new microscopic traffic simulation tool tightly integrated with the ITS-Cloud. The novel traffic management approaches were shown to outperform benchmark methods for a realistic range of traffic conditions and road network configurations. Unique to the work was the investigation of interactions between ITS components.
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Sepúlveda, Toepfer Carlos. "Instrumentation, model identification and control of an experimental irrigation canal." Doctoral thesis, Universitat Politècnica de Catalunya, 2008. http://hdl.handle.net/10803/5951.
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This thesis aims to develop control algorithms for irrigation canals in an experimental framework.These water transport systems are difficult to manage and present low efficiencies in practice.
As a result, an important percentage of water is lost, maintenance costs increase and water users follow a rigid irrigation schedule.
All these problems can be reduced by automating the operation of irrigation canals.
In order to fulfil the objectives, a laboratory canal, called Canal PAC-UPC, was equipped and instrumented in parallel with the development of this thesis. In general, the methods and solutions proposed herein were extensively tested in this canal.
In a broader context, three main contributions in different irrigation canal control areas are presented.
Focusing on gate-discharge measurements, many submerged-discharge calculation methods are tested and compared using Canal PAC-UPC measurement data. It has been found that most of them present errors around ±10%, but there are notable exceptions. Specifically, using classical formulas with a constant 0.611 contraction value give very good results (error<±6%), but when data is available, a very simple calibration formula recently proposed in the literature significantly outperform the rest (error<±3%). As a consequence, the latter is encouragingly proposed as the basis of any gate discharge controller.
With respect to irrigation canal modeling, a detailed procedure to obtain data-driven linear irrigation canal models is successfully developed. These models do not use physical parameters of the system, but are constructed from measurement data. In this case, these models are thought to be used in irrigation canal control issues like controller tuning, internal controller model in predictive controllers or simply as fast and simple simulation platforms. Much effort is employed in obtaining an adequate model structure from the linearized Saint-Venant equations, yielding to a mathematical procedure that verifies the existence of an integrator pole in any type of canal working under any hydraulic condition. Time-domain and frequency-domain results demonstrate the accuracy of the resulting models approximating a canal working around a particular operation condition both in simulation and experiment.
Regarding to irrigation canal control, two research lines are exploited. First, a new water level control scheme is proposed as an alternative between decentralized and centralized control. It is called Semi-decentralized scheme and aims to resemble the centralized control performance while maintaining an almost decentralized structure. Second, different water level control schemes based on PI control and Predictive control are studied and compared. The simulation and laboratory results show that the response and performance of this new strategy against offtake discharge changes, are almost identical to the ones of the centralized control, outperforming the other tested schemes based on PI control and on Predictive control. In addition, it is verified that schemes based on Predictive control with good controller models can counteract offtake discharge variations with less level deviations and in almost half the time than PI-based schemes.
In addition to these three main contributions, many other smaller developments, minor results and practical recommendations for irrigation canal automation are presented throughout this thesis.
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Ménard, Odette. "A solar climate control system using a water film flow to conserve energy in greenhouses /." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60540.
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One of the greatest problems encountered in greenhouses and buildings with large glazing is control of the internal atmosphere. The inherent characteristic of these buildings to act as solar collectors is to be used effectively for collecting and storing the excess solar energy. A new type of glazed roof, a Solar Climate Control roof system, was designed as a means to cool the interior environment of the greenhouses during the daytime and to heat during the nighttime or on overcast days.A heat exchanger-storage system, using water as a thermal mass is included in the design of the Solar Climate Control system. A film of water flows on the inner surface of the roof and absorbs the direct solar heat radiation, acting then as a cooling agent. The energy absorbed may be reused for nighttime heating.
An efficient water dispersion pipe for the Solar Climate Control system was developed. The use of a soap solution rather than water alone for the Solar Climate Control water film system permitted a significant reduction in pumping rate and improved uniformity of the film.
A computer simulation model was run to determine the energy loads for both a conventional (double glazed roof) greenhouse and one equipped with the Solar Climate Control system. The Solar Climate Control system shows low operating cost and very good efficiency in heat removal.
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Ma, Tsao-Tsung. "Use of multiple unified power flow controllers (UPFCs) to enhance power system operations and control." Thesis, University of Strathclyde, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366876.
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Ströbel, Ulrich. "Development of an online analysis and control system for individual quarter milking systems." Doctoral thesis, Humboldt-Universität zu Berlin, Landwirtschaftlich-Gärtnerische Fakultät, 2012. http://dx.doi.org/10.18452/16600.
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In der Milchviehhaltung nimmt die Anzahl der eingesetzten Onlinesensoren zu. Somit können bedeutende biologische Veränderungen bei Kühen z. B. Sekretveränderungen frühzeitig erkannt werden. Hohe mechanische Belastungen am Zitzengewebe, die z. B. zu Ringbildungen führen, treten beim Melken jedoch immer noch häufig auf. Eine nicht optimal angepasste Melktechnik kann einer der Gründe dafür sein. Hauptziel dieser Arbeit ist es, ein Vakuumregelungssystem für das zitzenendige Melkvakuum zu entwickeln, das in engen Zeitabständen reagiert. Das zitzenendige Melkvakuum soll durch die Regelung in der Saugphase bei großen Milchflüssen einen konstant niedrigen Vakuumabfall aufweisen. In der Entlastungsphase soll die Regelung dagegen einen konstant hohen Vakuumabfall erzeugen. Bei Nassmessungen (ISO 6690, 2007) wurden verschiedene viertelindividuelle Melksysteme im Melklabor und in Praxisbetrieben in Bezug auf ihr zitzenendiges Melkvakuum untersucht. Nachfolgend wurden verschiedene Vakuummess- und Aktorsysteme zur Vakuumbeeinflussung untersucht. Die wichtigsten Ergebnisse der Untersuchungen bestehen darin, dass die Konzeption für ein Vakuumregelungssystem gefunden und ein Prototyp gebaut werden konnte. Weiter wurden die Anforderungen an ein optimales zitzenendiges Melkvakuum erarbeitet. Das Konzept für das entwickelte Vakuumregelungssystem lässt erwarten, dass das zitzenendige Melkvakuum in der Saugphase auf 20 kPa bei einem Milchfluss von 0,25 l/min/ Euterviertel reduziert werden kann. Bei hohen Milchflüssen von 1,5 l/min/ Euterviertel und mehr wird das Vakuum in derselben Phase hingegen auf einen Mittelwert von 30 kPa eingestellt. Damit kann erstmals ein hohes Melkvakuum bei hohen und ein niedriges Melkvakuum bei niedrigen Milchflüssen erreicht werden. In Zukunft sollte das entwickelte Vakuumregelsystem zur Nutzung in allen viertelindividuellen Melksystemen angepasst werden.The number of online-sensors in dairy farming is increasing. In this manner, important biologically changes in cows as for example changes in secretion can be detected at an early stage. But high mechanical strains on the teat tissue during milking still occur frequently and can for example lead to formation of teat rings. A suboptimal adjusted milking technology can be one of the reasons for the mentioned observations. The objective of this dissertation was to develop a vacuum control system for the teat-end vacuum that can react in short time intervals. The teat-end vacuum produced by that control system should be with constant low vacuum reduction in suction phase at high milk flows. Moreover, in release phase the control system should provide constantly high vacuum reductions. In wet-tests (ISO 6690, 2007) several individual quarter milking systems in laboratory and practical milking parlours were evaluated in terms of their associated teat-end vacuum conditions. Several vacuum measuring and actuator systems for controlling the vacuum were tested. The most important result of the studies was that the general concept for a teat-end vacuum control system was developed, and a prototype of that system was produced. Important requirements for an optimum teat-end vacuum were revealed during that work. The concept for the planned vacuum control system suggests that it is possible to reduce the mean teat-end milking vacuum in the suction phase to 20 kPa at a flow rate of 0.25 l/min per udder quarter. At higher flow rates of 1.5 l/min and more per udder quarter, the teat-end vacuum is similar to the machine vacuum with a mean value of approximately 30 kPa. Therefore, for the first time, it is possible to supply a high teat-end vacuum at a high and a low teat-end vacuum at low milk flow rates. In the future, the developed vacuum control system should be adapted for installation in all types of individual quarter milking systems.
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Wu, Changhong. "Control of slurry flow, temperature and aggressive diamonds in chemical mechanical planarization." Thesis, The University of Arizona, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3701786.
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This dissertation presents a series of studies related to the study and control of slurry flow, process temperature, and aggressive diamonds in Chemical Mechanical Planarization (CMP). The purpose of these studies is to better understand the fundamentals of CMP and to explore solutions to some of CMP’s greatest challenges.
Within-wafer removal rate non-uniformity (WIWRRNU) is a critical parameter to determine film thickness planarity on a wafer-scale level and it grossly impacts yield. Resolving this issue continues to be an area of intense focus in the industry. The first study in this dissertation shows the feasibility of adopting a new method to improve WIWRRNU during copper CMP that is solely based on intentional local temperature manipulation of the pad. A pad surface thermal management system is developed to locally change pad surface temperature. This system consists of one or more thermal transfer modules contacting the pad surface. In this study, the system is employed to adjust the “center-fast” copper removal rate profile to illustrate its effect during the process. Results shows that, when two thermal transfer modules are employed, local removal rates in the wafer center region decrease significantly while maintaining the removal rates near the wafer edge thereby significantly improving WIWRRNU.
Another contribution of this dissertation is the investigation of the effect of pad groove design on slurry injection scheme during interlayer dielectric CMP. A novel slurry injector with multiple slurry outlets is designed, which provides optional slurry injection schemes (i.e. one injection point scheme and multi-injection point scheme). These schemes are compared with the standard slurry application method on a concentrically grooved pad and an xy-groove pad, respectively. On the concentrically grooved pad, the one injection point scheme generates significantly higher oxide removal rates (ranging from 22 to 35 percent) compared to the standard slurry application method at different slurry flow rates. On the xy-groove pad, the one injection point scheme still results in higher removal rates (ranging from 3 to 9 percent), however, its removal rate enhancement is not as high as that of the concentrically grooved pad. In order to further improve slurry availability on the xy-groove pad, the multi-injection point scheme is tested. Results show that the multi-injection point scheme results in significantly higher removal rates (ranging from 17 to 20 percent) compared to the standard slurry application method. This work underscores the importance of optimum slurry injection schemes for accommodating particular groove designs.
The last contribution of this dissertation involves a study regarding aggressive diamond characterization and wear analysis during CMP. A 3M A3700 diamond disk is used to condition a Cabot Microelectronics Corporation (CMC) D100 pad for 30 hours. The top 20 aggressive diamonds for two perpendicular disk orientations are identified before the polishing, as well as after 15- and 30-hour polishing. The furrow surface area generated by these top 20 aggressive diamonds and their evolution are analyzed and compared. Results show that the original top 20 aggressive diamonds identified before polishing are subjected to wear after the first 15-hour polishing as the furrow surface area that they generate decreases dramatically (by 47%). As these original aggressive diamonds are worn, seven new aggressive diamonds are “born” and join the new top 20 list for both disk orientations. After the second 15-hour wafer polishing, the furrow surface area of these new top 20 aggressive diamonds do not change significantly. The furrow surface area created by all the active diamonds exhibits the same trend as the top 20 aggressive diamonds, confirming that most pad conditioning work is performed by these aggressive diamonds and that the disk loses its aggressiveness in the first 15 hours of polishing and then maintains its aggressiveness during the second 15 hours, albeit to a lesser extent.
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Andersson, Henrik. "Model Based Control of Throttle, EGR and Wastegate : A System Analysis of the Gas Flows in an SI-Engine." Thesis, Linköpings universitet, Fordonssystem, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-140533.
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Due to governmental requirements on low exhaust gas emissions and the drivers request of fast response, it is important to be able to control the gas flow in a spark ignited engine accurately. The air into the cylinder is directly related to the torque generated by the engine. The technique with recirculation of exhaust gases (EGR) affect the air flow into the cylinder and increase the complexity of the control problem. In this thesis a mean value model for a spark ignited engine has been created. The basis was a diesel model from Linköping University that has been modified and parameterized with data from a test cell. The model has been used to study the gas exchange system with respect to the dynamic behaviors and nonlinearities that occur when the three actuators (throttle, wastegate and EGR-valve) are changed. Based on this analysis, some different control strategies have been developed and tested on the model. The presented results show that different control strategies give different behaviors and there is a trade-off between fast torque response and high precision for controlling the EGR-ratio. A control strategy is proposed containing two main feedback loops, prefiltering of the reference signal and a feedforward part.
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Dunn, Jason. "ON THE NATURE OF THE FLOW IN A SEPARATED ANNULAR DIFFUSER." Master's thesis, University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4101.
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The combustor-diffuser system remains one of the most studied sections of the turbomachine. Most of these investigations are due to the fact that quite a bit of flow diffusion is required in this section as the high speed flow exits the compressor and must be slowed down to enter the combustor. Like any diffusion process there is the chance for the development of an unfavorable adverse pressure gradient that can lead to flow separation; a cause of drastic losses within a turbine. There are two diffusion processes in the combustor-diffuser system: The flow first exits the compressor into a pre-diffuser, or compressor discharge diffuser. This diffuser is responsible for a majority of the pressure recovery. The flow then exits the pre-diffuser by a sudden expansion into the dump diffuser. The dump diffuser comprises the majority of the losses, but is necessary to reduce the fluid velocity within acceptable limits for combustion. The topic of active flow control is gaining interest in the industry because such a technique may be able to alleviate some of the requirements of the dump diffuser. If a wider angle pre-diffuser with separation control were used the fluid velocity would be slowed more within that region without significant losses. Experiments were performed on two annular diffusers to characterize the flow separation to create a foundation for future active flow control techniques. Both diffusers had the same fully developed inlet flow condition, however, the expansion of the two diffusers differed such that one diffuser replicated a typical compressor discharge diffuser found in a real machine while the other would create a naturally separated flow along the outer wall. Both diffusers were tested at two Reynolds numbers, 5x104 and 1x105, with and without a vertical wall downstream of the exit to replicate the dump diffuser that re-directs the flow from the pre-diffuser outlet to the combustor. Static pressure measurements were obtained along the OD and ID wall of the diffusers to determine the recovered pressure throughout the diffuser. In addition to these measurements, tufts were used to visualize the flow. A turbulent CFD model was also created to compare against experimental results. In the end, the results were validated against empirical data as well as the CFD model. It was shown that the location of the vertical wall was directly related to the amount of separation as well as the separation characteristics. These findings support previous work and help guide future work for active flow control in a separated annular diffuser both computationally and experimentally.M.S.A.E.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Aerospace Engineering MSAE
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Kabir, Md Nayim. "Smart coordinated distribution system control to enable high level penetration of rooftop PVs." Thesis, Queensland University of Technology, 2015. https://eprints.qut.edu.au/79956/1/MD%20Nayim_Kabir_Thesis.pdf.
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This thesis addresses voltage violation problem, the most critical issue associated with high level penetration of photovoltaic (PV) in electricity distribution network. A coordinated control algorithm using the reactive power from PV inverter and integrated battery energy storage has been developed and investigated in different network scenarios in the thesis. Probable variations associated with solar generation, end-user participation and network parameters are also considered. Furthermore, a unified data model and well-defined communication protocol to ensure the smooth coordination between all the components during the operation of the algorithm is described. Finally this thesis incorporated the uncertainties of solar generation using probabilistic load flow analysis.
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Dahlin, Hampus, and Martin Pihl. "Factors that Impact Inventory Levels in a Supermarket System Supplying a Manufacturing Line." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Industriell organisation och produktion, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-24069.
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Purpose - The purpose of this thesis is to identify factors that have an impact on supermarket inventory levels that supply a manufacturing line and investigate how the impact of these factors can be controlled. In order to fulfill the purpose it was broken down into two research questions. What factors have an impact on supermarket inventory levels supplying a manufacturing line? 2. How can the impact of these factors be controlled? Method - To answer the research questions a literature study and a case study were conducted. The empirical findings from the case study and the literature study were used to find the answer to the first research question. The identified factors in the first research question were then analysed with the theoretical framework in order to answer the second research question. Different techniques have been used in order to collect necessary data including documentation studies, interviews, observations and basic training in the case company’s procurement system (GILM). Findings - Total safety lead time, firm time and shortage impact were discovered during the case study. These factors were not to found during the literature study because they were specific parameters that are predetermined in the case company’s procurement system. Internal material handling and supermarket order quantity were factors also found during the case study. The identified factors are divided after which tool or method that can be used to gain control over the factor. Four different tools have been identified as solutions to gain control over the internal material handling. The factors that only have one identified tool as a solution are either case specific or not attentive in the theoretical framework as the other tools. Implications - The identified factors from the literature study are considered as common factors that can be applied for companies that have a supermarket inventory. If manufacturing companies are facing problems with their supermarket inventory levels they can increase control by investigating the tools and methods presented in this thesis. Contributions - The factors that were identified during the case study have contributed with new discoveries in the field of study, since there is limited research done in this subject regarding supermarket systems. Research limitations - More case studies could have been performed at similar companies, in order to investigate how generalizable the answers to both research questions are.
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Wamalwa, Fhazhil. "Optimal control of a conventional hydropower system with hydrokinetic/wind powered pumpback operation." Diss., University of Pretoria, 2017. http://hdl.handle.net/2263/61549.
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The need to ease pressure from the depleting fossil fuel reserves coupled with the rising global energy demand has seen a drastic increase in research and uptake of renewable energy sources in recent decades. Of the commonly exploited renewable energy resources, hydropower is currently the most popular resource accounting for 17% of the world's total energy generation, a portion which translates to 85% of the renewable energy share. However, despite the huge potential, hydropower is dependent on the availability of water resource, which is affected by climate change. During wet seasons, hydropower system operators are faced with a deluge of floods which results in excess power generation and spillage. The situation reverses in dry seasons where system operators are compelled to curtail power generation because of low water levels in the hydro reservoirs. The later situation is more pronounced in drought prone regions such as Southern Africa where some hydropower plants are completely shut down in dry seasons due to water shortage.
This dissertation focuses on the application of optimal control to hydropower plants with pumpback retrofits powered by on-site hydrokinetic and wind power systems. The first section of this work develops an optimal operation strategy for a high head hydropower plant retrofitted with hydrokinetic-powered cascaded pumpback system in dry season. The objective of pumpback operation is to recycle a part of the downstream discharged water back to the main dam to maintain a high water level required for optimal power generation. The problem is formulated as a discrete optimisation problem to simultaneously minimise the grid pumping energy demand, minimise the wear and tear associated with the switching frequency of the two pumps in cascade, maximise restoration of the reservoir volume through pumpback operation and maximise the use of on-site generated hydrokinetic power for pumping operation. Simulation results based on a practical case study show the pumping energy saving advantages of the cascaded pumping system as compared to a classical pumped storage (PS) system.
The second section of this work develops an optimal control system for assessing the effects of ecological flow constraints to the operation of a hydropower plant with a hydrokinetic-wind powered pumpback retrofit. The aim of the control law in this case is to use the allocated water to optimally meet the contractual obligations of the power plant. The problem is formulated as a discrete optimisation problem to maximise the energy output of the reservoir subject to some defined technical and hydrological constraints. In this system, pumping power is met primarily by the wind power generator output supplemented by the on-site generated hydrokinetic power. The excess hydrokinetic power is exported to the grid to meet the committed demand. Three different optimisation scenarios are developed: The first scenario is the baseline operation of the hydropower plant without any intervention. The second scenario incorporates the hydrokinetic-wind-powered pumpback operation in the optimal control policy. The third scenario includes the downstream flow constraint to the optimal control policy of the second optimisation scenario. Simulation results based on a practical case study show that ecological flow constraints have negative effects to the economic performance of a hydropower plant.Dissertation (MEng)--University of Pretoria, 2017.
MasterCard Foundation Scholars Program
Centre of New Energy Systems
University of Pretoria
Electrical, Electronic and Computer Engineering
MEng
Unrestricted
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Sarasua, Wayne Alexander. "SIG-GIS : a GIS based traffic signal coordination and information management system." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/19085.
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Hussein, Ahmed Abd Elmonem Ahmed. "Dynamical System Representation and Analysis of Unsteady Flow and Fluid-Structure Interactions." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/85626.
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A dynamical system approach is utilized to reduce the representation order of unsteady fluid flows and fluid-structure interaction systems. This approach allows for significant reduction in the computational cost of their numerical simulations, implementation of optimization and control methodologies and assessment of their dynamic stability. In the first chapter, I present a new Lagrangian function to derive the equations of motion of unsteady point vortices. This representation is a reconciliation between Newtonian and Lagrangian mechanics yielding a new approach to model the dynamics of these vortices. In the second chapter, I investigate the flutter of a helicopter rotor blade using finite-state time approximation of the unsteady aerodynamics. The analysis showed a new stability region that could not be determined under the assumption of a quasi-steady flow. In the third chapter, I implement the unsteady vortex lattice method to quantify the effects of tail flexibility on the propulsive efficiency of a fish. I determine that flexibility enhances the propulsion. In the fourth chapter, I consider the stability of a flapping micro air vehicle and use different approaches to design the transition from hovering to forward flight. I determine that first order averaging is not suitable and that time periodic dynamics are required for the controller to achieve this transition. In the fifth chapter, I derive a mathematical model for the free motion of a two-body planar system representing a fish under the action of coupled dynamics and hydrodynamics loads. I conclude that the psicform fish family are inherently stable under certain conditions that depend on the location of the center of mass.Ph. D.
We present modeling approaches of the interaction between flying or swimming bodies and the surrounding fluids. We consider their stability as they perform special maneuvers. The approaches are applied to rotating blades of helicopters, fish-like robots, and micro-air vehicles. We develop and validate a new mathematical representation for the flow generated by moving or deforming elements. We also assess the effects of fast variations in the flow on the stability of a rotating helicopter blade. The results point to a new stable regime for their operation. In other words, the fast flow variations could stabilize the rotating blades. These results can also be applied to the analysis of stability of rotating blades of wind turbines. We consider the effects of flexing a tail on the propulsive force of fish-like robots. The results show that adding flexibility enhances the efficiency of the fish propulsion. Inspired by the ability of some birds and insects to transition from hovering to forward motion, we thoroughly investigate different approaches to model and realize this transition. We determine that no simplification should be applied to the rigorous model representing the flapping flight in order to model transition phenomena correctly. Finally, we model the forward-swim dynamics of psciform and determine the condition on the center of mass for which a robotic fish can maintain its stability. This condition could help in designing fish-like robots that perform stable underwater maneuvers.
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Muse, Jonathan Adam. "An H-Infinity norm minimization approach for adaptive control." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34830.
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This dissertation seeks to merge the ideas from robust control theory such as H-Infinity control design and the Small Gain Theorem, L stability theory and Lyapunov stability from nonlinear control, and recent theoretical achievements in adaptive control. The fusion of frequency domain and linear time domain ideas allows the derivation of an H-Infinity Norm Minimization Approach (H-Infinity-NMA) for adaptive control architecture that permits a control designer to simplify the adaptive tuning process and tune the uncertainty compensation characteristics via linear control design techniques, band limit the adaptive control signal, efficiently handle redundant actuators, and handle unmatched uncertainty and matched uncertainty in a single design framework. The two stage design framework is similar to that used in robust control, but without sacrificing performance. The first stage of the design considers an ideal system with the system uncertainty completely known. For this system, a control law is designed using linear H-Infinity theory. Then in the second stage, an adaptive process is implemented that emulates the behavior of the ideal system. If the linear H-Infinity design is applied to control the emulated system, it then guarantees closed loop system stability of the actual system. All of this is accomplished while providing notions of transient performance bounds between the ideal system and the true system.
Extensions to the theory include architectures for a class of output feedback systems, limiting the authority of an adaptive control system, and a method for improving the performance of an adaptive system with slow dynamics without any modification terms. Applications focus on using aerodynamic flow control for aircraft flight control and the Crew Launch Vehicle.
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Wredh, Simon. "Neural Network Based Model Predictive Control of Turbulent Gas-Solid Corner Flow." Thesis, Uppsala universitet, Signaler och system, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-420056.
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Over the past decades, attention has been brought to the importance of indoor air quality and the serious threat of bio-aerosol contamination towards human health. A novel idea to transport hazardous particles away from sensitive areas is to automatically control bio-aerosol concentrations, by utilising airflows from ventilation systems. Regarding this, computational fluid dynamics (CFD) may be employed to investigate the dynamical behaviour of airborne particles, and data-driven methods may be used to estimate and control the complex flow simulations. This thesis presents a methodology for machine-learning based control of particle concentrations in turbulent gas-solid flow. The aim is to reduce concentration levels at a 90 degree corner, through systematic manipulation of underlying two-phase flow dynamics, where an energy constrained inlet airflow rate is used as control variable. A CFD experiment of turbulent gas-solid flow in a two-dimensional corner geometry is simulated using the SST k-omega turbulence model for the gas phase, and drag force based discrete random walk for the solid phase. Validation of the two-phase methodology is performed against a backwards facing step experiment, with a 12.2% error correspondence in maximum negative particle velocity downstream the step. Based on simulation data from the CFD experiment, a linear auto-regressive with exogenous inputs (ARX) model and a non-linear ARX based neural network (NN) is used to identify the temporal relationship between inlet flow rate and corner particle concentration. The results suggest that NN is the preferred approach for output predictions of the two-phase system, with roughly four times higher simulation accuracy compared to ARX. The identified NN model is used in a model predictive control (MPC) framework with linearisation in each time step. It is found that the output concentration can be minimised together with the input energy consumption, by means of tracking specified target trajectories. Control signals from NN-MPC also show good performance in controlling the full CFD model, with improved particle removal capabilities, compared to randomly generated signals. In terms of maximal reduction of particle concentration, the NN-MPC scheme is however outperformed by a manually constructed sine signal. In conclusion, CFD based NN-MPC is a feasible methodology for efficient reduction of particle concentrations in a corner area; particularly, a novel application for removal of indoor bio-aerosols is presented. More generally, the results show that NN-MPC may be a promising approach to turbulent multi-phase flow control.
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Upadhyay, Devesh. "Modeling and model base control design of the VGT-EGR system for intake flow regulation in diesel engines /." The Ohio State University, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=osu1486400446370507.
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Wang, Chia-Chuan, and 王嘉傳. "A gas flow control system integrating MEMS flow sensor." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/17698419680003583299.
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碩士國立交通大學
工學院半導體材料與製程設備學程
101
Gas control in the electronics industry and the semiconductor manufacturing are very important key process. Commonly in gas flow control system the key product is use mass flow controller to control flow rate generally called MFC (Mass Flow controller).Mass flow controller is combined the flow sensor, proportional valve, PID controller device, but when any device needs to re-calibration or maintenance and change the specifications in the production line or re-design will cause a trouble and inconvenience. This thesis focused on use new generation of MEMS fabrication process flow sensor to replace the traditional thermal flow sensor, and introduce how to combine independent proportional valve, PID controller, PLC and HMI to do a like MFC function flow control system. Because each component are independent modular system, so not only more convenient to maintenance and calibration, and via the independent modular components can be separately applied to various gas flow control system, and can be effectively used in industrial equipment.
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Chun-Chen, Lin, and 林俊臣. "Control of A Gas Flow Calibration System." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/81003939859308915658.
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碩士中原大學
化學工程研究所
86
The fluid transients caused by the enormous change of flow rate may be harmful to the piping system. The main purpose of this research is to discuss the fluid transients of a gas flow calibration system. Mathematical models of the fluid transients were derived by the principle of mass and momentum balance. The characteristic method was applied for numerical analysis. The simulation studies on the fluid transients of the calibration system were executed by this method. The effects of different operating conditionson the fluid transients were investigated in the simulation studies. PI control law was proposed to implement to the pressure and flow rate control of calibration system. The controller settings were obtained by the continuous cycling method and then fine-tuned using the IAE criterion. Simulation results show that the pressure and flow rate of the system would change enormously by some operating conditions such as the time of valve closing. The changes of the pressure or flow rate during the transient are larger for theshorter closing time. Since the pressure of the system is sensitive to the valve opening , control of pressure would be more difficult than that of flow rate. And the results show that the controlled point nearest to the valve have the best control performance of flow rate in the single pipeline system.
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Hsin-Chang, Cheng, and 鄭信彰. "Control of A Liquid Flow Calibration System." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/31410790966283955790.
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碩士中原大學
化學工程研究所
86
The fluid transients caused by the enormous change of flow rate maybe harmful to the piping system. The flow and pressure process in a liquid flow calibration system have highly interaction. The selection of the controlled point of pressure could have large effect on the control performance. The main purpose of this research is to concern the related topics smoothing the operation of the calibration system. Mathematical models of the fluid transients were derived by the principle of the mass and momentum balance. The characteristic method is applied for numerical analysis. The simulation studies on the fluid transients of the calibration system were executed by this method. A steady state equation governing the flow and pressure relation was also derived for the control purpose. Simulation results show that the elapsed time of the valve closing have the great effect on the fluid transients. The increase of the pressure during the transients is larger for the shorter closing time. It shows that the controlled point of pressure nearest to the closing valve have the best control performance. A decoupler was applied to reduce the interaction between the flow and pressure control loop.
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Li, Hsun-ming, and 李訓明. "Traffic flow control strategy on freeway system." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/43468138879860120815.
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碩士國立成功大學
交通管理(科學)學系
84
Congestion is nowadays one of the main problems on freeway system.Reduction of congestion is a main objective not only for insuring shortingand more reliable travel times, but also in reducing its indirect consequenceson pollution and fuel consumption thus improving the quality of life. System limit control deserves the most efficient one that has beenapproved to be appropriate for traffic congestion conditions in foreigncountries. This paper accordingly tries to develop a traffic density controller to eliminate the traffic congestion. The macroscopic traffic model adopted in this paper will be introducedto domestic people. A traffic density controller is improved which is proposedfirst by C.C.Chien , Y.Zhang, A.Stotsky. The traffic controller is designed tooperate traffic system in a desired traffic density to prevent the amplification of traffic congestion. We proposed the density rules to set the density goals to cooperate with the density controller. Finally, we collected the traffic flow characteristics that are createdfrom the traffic data on domestic freeway system to fit in the adopted macroscopic traffic model. From the simulation of difference traffic situation: close partly lane, close fully lane, upper grade lane, we can see the traffic congestion has been eliminated by the proposed density controller.
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Chen, Chen-Jen, and 陳昶任. "Cross-Platform Integrative, journalistic Flow Control System." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/46427531747320958368.
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碩士國立交通大學
資訊科學系
91
Today is global information explosion and newsmedia is the results by which huge information is filtered. Journalistic competition is more serious and all newsmedia want to achieve the goal, which is increasing news source, high up news determinacy and value, and costing down investigative report and edit. Cross-Platform Integrative, journalistic Flow Control System is a newsmedia processing system. All kinds of huge source is processed more streamlined and more cost-efficient based on gatekeeper theory to news content. These source include news group, mobile content, voice content, web system and XML system etc. All news content will be rewrite base on different platform and it will down operating cost. Besides, single time point news content can be translated to tracking news content by history search. Finally, re-evaluate system worked with these processing system will help newsman more professional on news content, and help newsmedia organization to evaluate news employee in impersonal point and some dimensional rule. This thesis consists of three major parts: (1) We describe today''s newsmedia, including newspaper, radio, television and network media. By introducing newsmedia, we picture system structure and how newsman can work together with this system. (2) We introduce what is gatekeeper theory at first. And then we physically exercise how news source process to news content cooperating by reporter, editor and master editor, and how to store content in XML way and publish to browser. (3) We outline system conditions and our acquaintance about this system. We also describe possible future work.
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Tu, Chih-Chien, and 杜志乾. "Production Control Policies in Flow Shop Manufacturing System." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/40642384806738851049.
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碩士國立清華大學
工業工程與工程管理學系
89
The paper tries to investigate and compare three production control policies, HP production control policy, zero production control policy and (z, Z) production control policy, in flow-shop manufacturing system. A HP production control policy is characterized by a number z*, which is regarded as the optimal amount of inventory to be kept. If current inventory level exceeds z*, the system be set to produce nothing；if less than z*, the system should be set to produce at the maximum rate；if the inventory level exactly equals z*, the system should be set to produce exactly enough to meet demand and thereby keep the inventory level at z*. A zero production control policy is also characterized by a number z* which is regarded equal zero. A (z, Z) production control policy is characterized by two control limits z < Z. The machine keeps on producing at its maximal capacity until the inventory level Z is reached. Once this inventory level is reached, we adjust the production rate of the machine to zero until the inventory level z is reached. We find that (z, Z) production control policy is better than zero production control policy in many cases. For example, in case that the capacity far more exceeds the demand, the usual belief is that zero production control policy can lower total cost. However, our simulation experiment results show that (z, Z) production control policy is better than zero production control policy. In case that the demand is close to the capacity, HP production control policy will be better than the other two policies. The simulation to estimate the expected inventory & shortage per unit time and to estimate the (z, Z) values for (z, Z) production control policy is based on that we model the unreliable single machine system in a renewal process. 一、製造系統或生產線的類型…………………………………………………..1 二、製造系統或生產線的生產控制策略問題…………………………………..1 三、本論文研究之製造系統及問題……………………………………………..2 四、本文章節架構………………………………………………………………..2 第貳章 生產控制策略文獻回顧及本文研究目的、方法及步驟…………………3 一、生產控制策略文獻回顧……………………………………………………..3 (一) HP production control policy……………………………………………..3 (二) 零庫存式之生產控制策略…………………………………………… ..6 (三) (z, Z) production control policy…………………………………………..8 二、研究目的、研究方法及步驟………………………………………………..9 第參章 三種生產控制策略在單機台系統之數學模型…………………………..11 一、系統共同環境…………………………………..…………………………..11 二、生產控制策略之比較模型……………………..…………………………..11 (一) HP production control policy模型……………………………………...13 (二) 零庫存式之生產控制策略模型……...…….………………………….14 (三) (z, Z) production control policy……...…….……...…………………….15 第肆章 單機台 (z, Z) 生產控制策略…...…….……...…………………..…...….17 一、(z, Z) 生產控制策略對存貨水準影響之觀察……...……………..…...….17 二、估算 (z, Z) 值之模擬方法……...…………………………..……..…...….19 (一) Check Method(對每組數據，檢驗 時間內的當機次數)…………20 (二) 計算每組數據之 …...……………………..…………..……..…...….23 (三) 計算每組數據之存貨數與缺貨數…………..………..…….....…...….26 三、實例演練……...……………………………….……………..……..…...….33 四、使用eM-plant 軟體，對此模擬方法之驗證…….……………..……..….35 第伍章 模擬驗證、比較與分析 …….…………..………………………..…..….37 一、HP control policy之 z* 值之驗證……..………………………..……..….37 二、三種生產控制策略之比較……..…………………..………………..…..….40 第陸章 研究貢獻與未來可進行研究之方向……………..……………..…….….43 一、研究貢獻…….…………..………………………..…..…………..…………43 二、未來可進行研究之方向……………………..…..………………………..…43 第柒章 參考文獻…….…………..………………………..…….…………………45 第捌章 附錄………………………………………………………………………..47 附錄一：模擬方法之程式碼……………………………………………………47 附錄二：單機台HP production control policy 程式碼………………………57 附錄三：單機台每天存、缺貨紀錄程式碼……………………………….……58 附錄四：(z, Z) 生產控制策略之程式碼……………………….………….……59
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LIAO, CHIEN CHIH, and 廖建智. "Some Flow-control Techniques for IC Manufacturing System." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/32099402359852761549.
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碩士東海大學
數學系研究所
86
This thesis is the continuation of a series research which intendsto create a scientific, long term evaluation of IC manufacturing systems.Three flow-control techniques have been designed to reduce the returnpercentage of wafers in process when their allowed waiting times are over.These techniques also greatly increase the throughput of the products.Technique C which based on estimated time schedule to decide wafer dispatchpriority for each step is untraditional and unique. It is simple and easy to apply on IC production line.-1 -aSome Flow-control Techniques for IC Manufacturing System