• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 8
  • 4
  • 1
  • Tagged with
  • 15
  • 15
  • 8
  • 8
  • 6
  • 5
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

Parametric Programming in Control Theory

Spjøtvold, Jørgen January 2008 (has links)
<p>The main contributions in this thesis are advances in parametric programming. The thesis is divided into three parts; theoretical advances, application areas and constrained control allocation. The first part deals with continuity properties and the structure of solutions to convex parametric quadratic and linear programs. The second part focuses on applications of parametric quadratic and linear programming in control theory. The third part deals with constrained control allocation and how parametric programming can be used to obtain explicit solutions to this problem.</p>

Parametric Programming in Control Theory

Spjøtvold, Jørgen January 2008 (has links)
The main contributions in this thesis are advances in parametric programming. The thesis is divided into three parts; theoretical advances, application areas and constrained control allocation. The first part deals with continuity properties and the structure of solutions to convex parametric quadratic and linear programs. The second part focuses on applications of parametric quadratic and linear programming in control theory. The third part deals with constrained control allocation and how parametric programming can be used to obtain explicit solutions to this problem.


Melegari, Luis Fernando 15 December 2011 (has links)
The use of CAM system to create tool s trajectories in outline of simple geometry depends directly of knowledge and ability from user in how to maintain the information and make use of available riches from these systems. The parametric program requires a solid knowledge in CN programming and the results referring to CNC machine s performance are directly connect to the way of programming to obtain these results. The aim of this study was to develop a practice s analysis between parametric program and a CAM system in a specific CNC machine, based on acting time and speed of tool s progress to each programming method. The counting of time was accomplished through CNC controller, which shows the execution time of each program from its beginning until receiving or reading the stop command. The comparison between these programming methods created results that depend of the programming way, but who receive interference of controller s technologies recourses to put in action the CNC axis machine. With these testing, it was possible to demonstrate, by means of parametric programs, an increase of 65% in performance, when compared to other programming methods. / A utilização de sistemas CAM para a geração de trajetórias de ferramenta em contornos de geometria simples depende diretamente do conhecimento e da capacidade do usuário na alimentação das informações e na utilização dos recursos disponíveis desses sistemas. A programação paramétrica exige uma base sólida no conhecimento da programação CN e os resultados que se referem ao desempenho da máquina CNC estão diretamente ligados à forma de programação para a obtenção desses resultados. O objetivo deste estudo foi desenvolver uma análise de desempenho entre a programação paramétrica e um sistema CAM em uma máquina CNC específica, com base nos tempos de execução e velocidade de avanço da ferramenta para cada método de programação. A contagem de tempo foi realizada através do controlador CNC, que indica o tempo de execução de cada programa a partir do seu início até o recebimento ou leitura do comando de parada. A comparação entre esses métodos de programação gerou resultados que dependem diretamente da forma de programação, mas que recebem interferência dos recursos tecnológicos do controlador para o acionamento dos eixos da máquina CNC. Com essas experimentações, foi possível demonstrar, através de programas paramétricos, um aumento no desempenho em até 65% quando comparado a outros métodos de programação.

Možnosti systému Sinumerik 840D při programování obráběcích strojů / Sinumerik 840D tools for NC programming of machines

Hrabal, Josef January 2011 (has links)
This thesis deals with the possibilities of SINUMERIK 840D applications on turning centers. The first part of the thesis is focused on methods of NC programming and especially on the description and operation of the control system through the tutorial SinuTrain 7.5 Ed. 2. The second part of thesis is generated NC programs on the selected components with parametric typing and using a counter. Production technology and the creation of the NC program is created for the CNC machine SP280SY. In conclusion, the thesis is done machining simulation machine with output times.

Využití parametrického programování pro obrábění obecných ploch / The use of parametrical programming for complex part machining

Skácel, Jan January 2015 (has links)
Thesis consists of theoretical introduction to programming in G-code, underlying mathematical principles and methods how to program general curves and surfaces. There are seven exam

Parametrické programování v řídicím systému Fanuc / Parametric programming in Fanuc control system

Hynčica, Vojtěch January 2017 (has links)
The diploma thesis is focused on the use of parametric programming family of workpieces. The practical part includes the design of production technology and the creation of a parametric programs for the production of a given group of workpieces using a workpiece measuring probe. The use of common and system variables can be applied to the toolpath programming and the measurement of workpiece offsets, workpieces and machined areas by a workpiece probe and for measuring and checking tools using a tool probe. Measured values can be used in conditional programming to increase the level of automation of the manufacturing process.

Integration of energy management  and production planning : Application to steelmaking industry

Labrik, Rachid January 2014 (has links)
Steelmaking industry, one of the most electricity-intensive industrial processes, is seeking for new approaches to improve its competitiveness in terms of energy savings by taking advantage of the volatile electricity prices. This fluctuation in the price is mainly caused by the increasing share of renewable energy sources, the liberalization of energy markets and the growing demand of the energy. Therefore, making the production scheduling of steelmaking processes with knowledge about the cost of the energy may lead to significant cost savings in the electricity bills. With this aim in mind, different models are developed in this project in order to improve the existing monolithic models (continuous-time based scheduling) to find an efficient formulation of accounting for electricity consumption and also to expand them with more detailed scheduling of Electric Arc Furnace stage in the production process. The optimization of the energy cost with multiple electricity sources and contracts and the production planning are usually done as stand-alone optimizers due to their complexity, therefore as a new approach in addition to the monolithic model an iterative framework is developed in this work. The idea to integrate the two models in an iterative manner has potential to be useful in the industry due to low effort for reformulation of existing models. The implemented framework uses multiparametric programming together with bilevel programming in order to direct the schedule to find a compromise between the production constraints and goals, and the energy cost. To ensure applicability heuristic approaches are also examined whenever full sized models are not meeting computational performance requirements. The results show that the monolithic model implemented has a considerable advantage in terms of computational time compared to the models in the literature and in some cases, the solution can be obtained in a few minutes instead of hours. In the contrary, the iterative framework shows a bad performance in terms of computational time when dealing with real world instances. For that matter a heuristic approach, which is easy to implement, is investigated based on coordination theory and the results show that it has a potential since it provides solutions close to the optimal solutions in a reasonable amount of time. Multiparametric programming is the main core of the iterative framework developed in this internship and it is not able to give the solutions for real world instances due to computational time limitations. This computational problem is related to the nature of the algorithm behind mixed integer multiparametric programming and its ability to handle the binary variables. Therefore, further work to this project is to develop new approaches to approximate multiparametric technique or develop some heuristics to approximate the mp-MILP solutions.

Rozbor výroby hřídelí přesných servomotorů / Analysis of the production shafts precision actuators

Železný, Lukáš January 2011 (has links)
The thesis is focused on making the most efficient actuator shaft, using machinery company. Using Fanuc's control system on all machines with examples of their use in practice. Production and integration of a special holder for the drill stage.

Možnosti softwaru SinuTrain Operate 4.4 při programování CNC obráběcích strojů / Possibilities of SinuTrain Operate 4.4 software in programming of CNC machine tools

Ošťádal, Josef January 2013 (has links)
This thesis points to the knowledge of milling technologies and the various possibilities by programming CNC machines. Further shortly describes hard materials, with methods of their machining and basics of workpiece clamping. Explains and points out to the various software options Sinumerik Operate 4.4 - ShopMill during processing program of designed component produced by using milling technology.

Structure-Exploiting Numerical Algorithms for Optimal Control

Nielsen, Isak January 2017 (has links)
Numerical algorithms for efficiently solving optimal control problems are important for commonly used advanced control strategies, such as model predictive control (MPC), but can also be useful for advanced estimation techniques, such as moving horizon estimation (MHE). In MPC, the control input is computed by solving a constrained finite-time optimal control (CFTOC) problem on-line, and in MHE the estimated states are obtained by solving an optimization problem that often can be formulated as a CFTOC problem. Common types of optimization methods for solving CFTOC problems are interior-point (IP) methods, sequential quadratic programming (SQP) methods and active-set (AS) methods. In these types of methods, the main computational effort is often the computation of the second-order search directions. This boils down to solving a sequence of systems of equations that correspond to unconstrained finite-time optimal control (UFTOC) problems. Hence, high-performing second-order methods for CFTOC problems rely on efficient numerical algorithms for solving UFTOC problems. Developing such algorithms is one of the main focuses in this thesis. When the solution to a CFTOC problem is computed using an AS type method, the aforementioned system of equations is only changed by a low-rank modification between two AS iterations. In this thesis, it is shown how to exploit these structured modifications while still exploiting structure in the UFTOC problem using the Riccati recursion. Furthermore, direct (non-iterative) parallel algorithms for computing the search directions in IP, SQP and AS methods are proposed in the thesis. These algorithms exploit, and retain, the sparse structure of the UFTOC problem such that no dense system of equations needs to be solved serially as in many other algorithms. The proposed algorithms can be applied recursively to obtain logarithmic computational complexity growth in the prediction horizon length. For the case with linear MPC problems, an alternative approach to solving the CFTOC problem on-line is to use multiparametric quadratic programming (mp-QP), where the corresponding CFTOC problem can be solved explicitly off-line. This is referred to as explicit MPC. One of the main limitations with mp-QP is the amount of memory that is required to store the parametric solution. In this thesis, an algorithm for decreasing the required amount of memory is proposed. The aim is to make mp-QP and explicit MPC more useful in practical applications, such as embedded systems with limited memory resources. The proposed algorithm exploits the structure from the QP problem in the parametric solution in order to reduce the memory footprint of general mp-QP solutions, and in particular, of explicit MPC solutions. The algorithm can be used directly in mp-QP solvers, or as a post-processing step to an existing solution. / Numeriska algoritmer för att effektivt lösa optimala styrningsproblem är en viktig komponent i avancerade regler- och estimeringsstrategier som exempelvis modellprediktiv reglering (eng. model predictive control (MPC)) och glidande horisont estimering (eng. moving horizon estimation (MHE)). MPC är en reglerstrategi som kan användas för att styra system med flera styrsignaler och/eller utsignaler samt ta hänsyn till exempelvis begränsningar i styrdon. Den grundläggande principen för MPC och MHE är att styrsignalen och de estimerade variablerna kan beräknas genom att lösa ett optimalt styrningsproblem. Detta optimeringsproblem måste lösas inom en kort tidsram varje gång som en styrsignal ska beräknas eller som variabler ska estimeras, och således är det viktigt att det finns effektiva algoritmer för att lösa denna typ av problem. Två vanliga sådana är inrepunkts-metoder (eng. interior-point (IP)) och aktivmängd-metoder (eng. active-set (AS)), där optimeringsproblemet löses genom att lösa ett antal enklare delproblem. Ett av huvudfokusen i denna avhandling är att beräkna lösningen till dessa delproblem på ett tidseffektivt sätt genom att utnyttja strukturen i delproblemen. Lösningen till ett delproblem beräknas genom att lösa ett linjärt ekvationssystem. Detta ekvationssystem kan man exempelvis lösa med generella metoder eller med så kallade Riccatirekursioner som utnyttjar strukturen i problemet. När man använder en AS-metod för att lösa MPC-problemet så görs endast små strukturerade ändringar av ekvationssystemet mellan varje delproblem, vilket inte har utnyttjats tidigare tillsammans med Riccatirekursionen. I denna avhandling presenteras ett sätt att utnyttja detta genom att bara göra små förändringar av Riccatirekursionen för att minska beräkningstiden för att lösa delproblemet. Idag har behovet av  parallella algoritmer för att lösa MPC och MHE problem ökat. Att algoritmerna är parallella innebär att beräkningar kan ske på olika delar av problemet samtidigt med syftet att minska den totala verkliga beräkningstiden för att lösa optimeringsproblemet. I denna avhandling presenteras parallella algoritmer som kan användas i både IP- och AS-metoder. Algoritmerna beräknar lösningen till delproblemen parallellt med ett förutbestämt antal steg, till skillnad från många andra parallella algoritmer där ett okänt (ofta stort) antal steg krävs. De parallella algoritmerna utnyttjar problemstrukturen för att lösa delproblemen effektivt, och en av dem har utvärderats på parallell hårdvara. Linjära MPC problem kan också lösas genom att utnyttja teori från multiparametrisk kvadratisk programmering (eng. multiparametric quadratic programming (mp-QP)) där den optimala lösningen beräknas i förhand och lagras i en tabell, vilket benämns explicit MPC. I detta fall behöver inte MPC problemet lösas varje gång en styrsignal beräknas, utan istället kan den förberäknade optimala styrsignalen slås upp. En nackdel med mp-QP är att det krävs mycket plats i minnet för att spara lösningen. I denna avhandling presenteras en strukturutnyttjande algoritm som kan minska behovet av minne för att spara lösningen, vilket kan öka det praktiska användningsområdet för mp-QP och explicit MPC.

Page generated in 0.1283 seconds