Filtyp
This thesis deals with two aspects of recursive state estimation: distributed estimation and estimation for hybrid systems. In the first part, an approximate distributed Kalman filter is developed. Nodes update their state estimates by linearly combining local measurements and estimates from their neighbors. This scheme allows nodes to save energy, thus prolonging their lifetime, compared to centr
Popular Abstract in Swedish En ny typ av reaktor för kemikalie och läkemedelsproduktion är under utveckling av Alfa Laval AB, ett svenskt företag som är en världsledande tillverkare av värmeväxlare. Den nya reaktortypen, som kallas för plattreaktor, kombinerar den höga värmeöverföringsförmågan från plattvärmeväxlaren med den effektiva mikro-mixningen av kemikalier som är typisk för en mikro-reaktoA new chemical reactor, the Alfa Laval Plate Reactor, is being developed by Alfa Laval, a Swedish world-leading heat exchanger company. The plate reactor combines the high-heat-transfer capabilities of plate heat exchangers with the efficient mixing and reaction control typical of microreactors. With this new concept, highly exothermic reactions can be produced using more concentrated reactants an
The first part of the thesis deals with adaptive CPU resource management for multicore platforms. The work was done as a part of the resource manager component of the adaptive resource management framework implemented in the European ACTORS project. The framework dynamically allocates CPU resources for the applications. The key element of the framework is the resource manager that combines feedfor
Digital controllers are traditionally implemented using periodic sampling, computation, and actuation events. As more control systems are implemented to share limited network and CPU bandwidth with other tasks, it is becoming increasingly attractive to use some form of event-based control instead, where precious events are used only when needed. Forms of event-based control have been used in prac
High-energy linear particle accelerators enable exploration of the microscopic structure of pharmaceuticals, solar cells, fuel cells, high-temperature superconductors, and the universe itself. These accelerators accelerate charged particles using oscillating magnetic fields that are confined in metal cavities. The amplitudes and phases of the electromagnetic fields need to be accurately controlled
Production of many proteins can today be made using genetically modified organisms. One of the most frequently used host organisms is the bacterium Escherichia coli. A difficulty encountered in cultivations of E. coli is the accumulation of the metabolic by-product acetate which inhibits cell growth and production of a desired protein. Formation of acetate occurs under anaerobic cond
Popular Abstract in Swedish Reglering och kommunikation med störande brus Hur kan man på bästa möjliga sätt skicka data, till exempel en ljudsignal, när kommunikationen störs av brus och ändå måste ske snabbt? Och hur kan man på bästa sätt styra en process när styrsystemet begränsas av dålig kommunikation? Dessa frågor har undersökts i avhandlingen Control and Communication with Signalto-Noise This thesis is about two problems in the intersection of communication and control theory. Their common feature is that they involve communication over an additive white noise channel with a signal-to-noise ratio (SNR) constraint. The first problem concerns the transmission of a real-valued signal from a partially observed Markov source. The distortion criterion is the mean squared error and the
Popular Abstract in Swedish Avhandlingen behandlar reglertekniska problem orsakade av friktion. Tre aspekter behandlas: modellering, analys av självsvängningar orsakade av friktion och friktionskompensering. En ny relativt enkel matematisk modell för friktion presenteras och studeras. Modellen kan återge experimentella observationer av friktionsbeteende. Matematiska verktyg för att bestämma självsFriction-related problems are frequently encountered in control systems. This thesis treats three aspects of such problems: modeling, analysis, and friction compensation. A new dynamic friction model is presented and investigated. The model is described by a first order nonlinear differential equation with a reasonable number of parameters, yet it captures most of the experimentally observed frict
This thesis covers areas within estimation and optimal control of vehicles, in particular four-wheeled vehicles. One topic is how to handle delayed and out-of-sequence measurements (OOSMs) in tracking systems. The motivation for this is that with technological development and exploitation of more sensors in tracking systems, OOSMs gain more significance in various applications. The thesis derives
The thesis treats model reduction for linear time-varying systems. Time-varying models appear in many fields, including power systems, chemical engineering, aeronautics, and computational science. They can also be used for approximation of time-invariant nonlinear models. Model reduction is a topic that deals with simplification of complex models. This is important since it facilitates analysis an
Popular Abstract in Swedish See attachment in related materialThe combustion engine is today the dominant technology for transportation of goods and people world-wide. Concerns for global warming, toxic exhaust emissions, as well as cost and availability of fuel have in recent years created incentives for technological evolution of combustion engines. More sophisticated engine instrumentation with additional degrees of freedom has been added to the engine de
Different aspects of hybrid control systems are treated: analysis, simulation, design and implementation. A systematic methodology using extended Lyapunov theory for design of hybrid systems is developed. The methodology is based on conventional control designs in separate regions together with a switching strategy. Dynamics are not well defined if the control design methods lead to fast mode sw
Control design is often done based on simplified models. After design it is necessary to verify that the real closed loop system behaves well. This is mostly done by experiments and simulations. Theoretical analysis is an important complement to this that can help to verify critical cases. Structural information about uncertainties, time-variations, nonlinearities, and signals can be described by
Popular Abstract in Swedish En industrirobot är en flexibel programmerbar maskin som bör användas för sådant arbete som inte lämpar sig för människan att utföra. Olika tekniska begränsningar i dagens styrsystem begränsar dock robotars tillämpbarhet. Avhandlingen föreslår ett nytt sätt att bygga upp robotstyrsystem så att roboten på bästa sätt skall kunna tjäna människan.Industrial robots play a key role in manufacturing systems. Robots are distinguished from other types of machinery mainly on the basis of their programmability and ability to be adaptable to different tasks. The use of computer control to achieve desired flexibility implies that software issues for embedded control systems are central for the applicability and utilization of the equipment. The str
