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Dissertations / Theses on the topic 'Steering systems'
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Liebon, Alexander, and Daniel Rääf. "Raalie steering systems." Thesis, Halmstad University, School of Business and Engineering (SET), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-2525.
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Under HT08 och VT09 har vi under vårt examensarbete tagit fram en ny mekanisk produkt. Det är ett mekaniskt styrsystem för sjukhussängar. Det är ett enkelt och billigt system, och det kommer att underlätta för personalen på sjukhusen runt om i landet. Då produkten gör det lättare för personalen att kontrollera sängen, samt att det nu räcker med en person som utför arbetet med att knuffa sängen.
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Senga, Masaaki. "Modeling and analysis of power steering systems." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/11770.
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Dell’Amico, Alessandro. "Pressure Control in Hydraulic Power Steering Systems." Licentiate thesis, Linköpings universitet, Fluida och mekatroniska system, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-100841.
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There is a clear trend in the vehicle industry to implement more safetyrelated functions, where the focus is on active safety systems and today the steering system is also involved. Steering-related active safety functions can only be realised with a steering system that allows electroniccontrol of either the road wheel angle or the torque required to steer the vehicle, called active steering. The high power requirement of heavy vehicles means they must rely on hydraulic power to assist the driver. Thesystem is a pure hydro-mechanical system with an open-centre circuit activated by the driver’s steering action and suffers from poor energy efficiency. The main task of the hydraulic system is to control the pressure in the assistance cylinder in such a way that it eases the load on the driver. This work suggests a way to design and evaluate a self-regulating pressure control valve for use as actuator in the steering system. This valve can be made small and fast and is electronically controlled to enable active steering. It is based on a closed-centre circuit and has therefore the potential to improve energy efficiency. The aim of this work has been to investigate the possibility for the valve to perform as the original open-centre valve. The suggested approach is a model-based design and evaluation process where an optimisation routine is used to design the valve. Together with a validated model of the steering system, the new concept is compared with the original system. A hardware-inthe-loop simulation test rig has also been designed and built with the possibility to test a closed-centre steering system. It has partly been used to support the modelling process and partly to verify that a closedcentre steering system is a feasible solution. The simulation results have shown that the designed valve can perform sufficiently well compared to the original system.
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Yamamoto, Kazusa. "Control of electromechanical systems, application on electric power steering systems." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAT069/document.
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De nos jours, la plupart des véhicules sont équipés de Directions Assistées Electriques (DAE). Ce type de systèmes d'aide à la conduite permet de réduire les efforts que le conducteur doit fournir pour tourner les roues. Ainsi, grâce à un moteur électrique, la DAE applique un couple additionnel en accord avec le comportement du conducteur et la dynamique du véhicule. Il est donc nécessaire de développer une commande en couple basée en particulier sur le signal provenant d'un capteur mesurant le couple agissant au niveau de la barre de torsion (correspondant à une image du couple conducteur). Ce composant est donc essentiel au fonctionnement de la DAE. Or, une défaillance de ce capteur entraine le plus souvent une coupure de l'assistance, pouvant mener à un risque d'accidents. Au regard de la sécurité fonctionnelle, un développement d'un mode de sécurité est recommandé, par de plus en plus de constructeurs automobiles. D'autre part, le marché des équipementiers automobiles reste un secteur très concurrentiel où une baisse des coûts de production est un challenge constamment recherché afin de gagner de nouvelles parts de marchés. Cet aspect de réduction du nombre de capteurs et d'analyse de la dynamique du véhicule s'inscrit donc dans le prolongement de la stratégie de sécurité. Cette thèse, menée au sein de JTEKT Europe, aborde ces divers enjeux. Après une présentation des différents systèmes de directions assistés électriques, des modèles sont présentés pour être utilisés lors de la conception de lois de commande et d'estimateurs. Ensuite deux méthodes d'estimation du couple conducteur sujet aux perturbations de la route et aux bruits de mesures sont proposées : la première est un observateur proportionnel intégral (PI) à synthèse mixte $H_infty/H_2$, et la seconde une approche par filtrage $H_infty$. Puis plusieurs stratégies de commande sont proposées suivant deux cas de figures distincts, soit en utilisant un observateur PI qui estime les états du système et le couple conducteur (LQR, commande LPV par retour d'état), soit en faisant abstraction d'estimateur de couple conducteur (commande $H_infty$ par retour de sortie dynamique). Ce dernier aspect présente l'avantage de nécessiter moins de mesures que le précédent. Ces approches ont été validées en simulation et mises en œuvre sur un véhicule prototype où des résultats prometteurs ont été obtenusNowadays, modern vehicles are equipped with more and more driving assistance systems, among them Electric Power Steering (EPS) helps the driver to turn the wheels. Indeed, EPS provides through an electric motor, an additional torque according to the driver's behaviour and the vehicle's dynamics to reduce the amount of effort required to the driver. Therefore, a torque control is developed based on the torque sensor signal which measures in practice the torsion bar torque (corresponding to an image of the driver torque). Consequently, this component is essential to the functioning of EPS systems.Indeed, a torque sensor failure usually leads to shut-off the assistance which may increase the risk of accident. Regarding functional safety, a back-up mode is recommended and required by more and more car manufacturers. On the other hand, a major challenge for automotive suppliers is to reduce cost production in order to meet growing markets demands and manage in the competitive sector. This issue considering a reduction of sensors' numbers and analysis of vehicle's dynamics is therefore an extension of applying the safety strategy. This thesis, carried out within JTEKT Europe, addresses these various issues.After introducing an overview of the different EPS systems, some models used for the design of controllers and estimators are presented. Then, two methods to estimate the driver torque subject to road disturbances and noise measurements are proposed: the first is a proportional integral observer (PI) with mixed synthesis $H_infty / H_2 $, whereas the second is an $ H_infty $ filtering approach. Then, several control strategies are proposed according to two different cases, either by using a PI observer which estimates the system states and the driver torque (LQR, LPV feedback control) or by not taking into account the driver torque estimation ($ H_infty $dynamic output feedback control). This latter approach has the advantage to require less measurements than the previous one. These approaches have been validated in simulation and implemented on a prototype vehicle where promising results have been obtained
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Sherif, M. "Decision point steering in optical fibre communication systems." Thesis, University of Kent, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233964.
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Asghar, Sajjad. "Exact steering in control of moment gyroscope systems." Thesis, University of Surrey, 2008. http://epubs.surrey.ac.uk/770151/.
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Single Gimbal Control Moment Gyroscopes (CMGs) are thought to be efficient actuators for the attitude control of the new generation of small and agile satellites. CMGs belong to a class of actuators known as momentum exchange devices. This thesis presents a detailed formulation of three-axis attitude dynamics and control of a satellite equipped with a cluster of n momentum exchange devices (which include CMGs and reaction wheels).
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Li, Hong. "Measuring systems for active steering of railway vehicles." Thesis, Loughborough University, 2001. https://dspace.lboro.ac.uk/2134/6790.
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This thesis studies measuring systems for active steering of railway vehicles. The aim of the study is to develop state estimation techniques to provide high integrity feedback variables for the active steering of railway vehicles. Practicality and provision of high-integrity data are two important aspects of the work. To avoid the use of expensive sensors and complex instrumentation, practical techniques for estimating vehicle variables are developed where only economical measurements are used and they can be easily implemented. The conventional solid-axle wheelset and wheelset with independently-rotating wheels are studied and their mathematical models are developed. The fundamental stability problem of these two models is analysed from a control engineering viewpoint for studies of actively-controlled wheelsets. The Kalman filters are then developed for these models to estimate all state variables, particularly variables of the wheelset relative to the track such as lateral displacement and yaw angle which are needed for active control. A number of sensing options are also identified, analysed for performance and assessed in a comparative sense. Fault detection and isolation schemes are then studied for the estimation techniques developed. Finally, some applications are considered. The techniques and analysis methods developed for the single wheel pair are extended and applied to a MKII coach and a two-axle railway vehicle. The estimation of cant deficiency for tilting trains is explored, and also the possibility of state estimation for a real profiled wheel.
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Sotomayor, Martínez Rodrigo. "System theoretic process analysis of electric power steering for automotive applications." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/105318.
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Thesis: S.M. in Engineering and Management, Massachusetts Institute of Technology, Engineering Systems Division, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 101-103).
The automotive industry is constantly challenged with meeting and exceeding customer expectations while reducing time to market of new products in order to remain competitive. Providing new features and functionality into vehicles for customer satisfaction is becoming more challenging and driving design complexity to a higher level. Although traditional methods of Product Development Failure Mode identification such as FMEA (Failure Mode and Effect Analysis) or FTA (Fault Three Analysis) have been used to analyze failures in automotive systems, there are limitations when it comes to design errors, flawed requirements, human factors implications, and component interaction accidents in which all components operated as required but the system behavior was not as expected. In order to determine if there is room for improvement in current automotive product development process, this thesis applies Dr. Nancy Leveson's Systems-Theoretic Process Analysis (STPA) technique to compare and contrast with a Failure Modes and Effects Analysis (FMEA) approach as used in the automotive industry through a case study. A formal method of comparing results is proposed. This study found limitations with FMEA in terms of identifying unsafe interactions between systems, anticipating human error and other behaviors dependent on human interaction, identifying engineering design flaws, and producing requirements. STPA was able to find causes that had a direct relationship with those found in FMEA while also finding a portion of causes related to a higher level of abstraction of those in FMEA. STPA also found a subset of causes that FMEA was not able to find, which relate mainly to engineering design flaws and system interaction.
by Rodrigo Sotomayor Martínez.
S.M. in Engineering and Management
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Zabel, D. F. "Structure-borne sound transmission within electric power steering systems." Thesis, University of Salford, 2018. http://usir.salford.ac.uk/48186/.
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Transfer path analysis (TPA) is an established and valuable tool in the automotive industry, to determine the contributions of structure-borne sound sources to receiver responses at target positions. The classical TPA approach is based on contact forces at the interface between source and receiver to characterise the dynamic loads induced by the source and frequency response functions (FRFs) to quantify the transfer paths of the sound from the interface locations to the target positions. With knowledge of the determined contributions it is then possible to decide whether source loads or FRFs must be improved to optimise the target quantities. Recently a timesaving improvement to classical TPA has been proposed, where the loads are characterised using the in-situ blocked force method, so that dismantling of source and receiver is not necessary. This method is therefore called in-situ TPA. However, if the contributions of internal structure-borne sound sources to the overall vibro-acoustic behaviour of a product are desired it is of benefit if the target quantities are blocked forces. Thus it would be possible to virtually couple the product with the properties of an overall receiver. Therefore this thesis presents a TPA approach called “blocked force transmissibility transfer path analysis” (bfTPA). In this context, the proposed internal-source-path-receiver-model (ISPRM) poses the theoretical basis of bfTPA. The aim of the presented novel TPA is to determine the contribution of internal structure-borne sound sources to an overall target quantity of a product. The presented approach uses the vector of in-situ blocked forces measured externally at the contact interface of the overall product and a corresponding set of “blocked force transmissibility” (BFT) functions relating the external coupling degrees of freedom (DOFs) to the internal source DOFs in order to propagate the external in-situ blocked forces back to multiple internal in-situ blocked forces. To prove the methodology of the presented approach three case studies, which increase in complexity, were carried out experimentally. The case studies concern a beam and an electric power steering system with paraxial servo unit (EPSapa), respectively. EPSapa systems consist of multiple embedded vibrational components which are defined as “internal sources”. The electric motor, the ball nut assembly and the toothed belt are identified as the main internal sources of an EPSapa system. Hence they are characterised by means of experimentally determined blocked forces. For the determination, micro electro mechanical systems (MEMS) accelerometers are embedded at the so called “internal interfaces”. This poses a novel application of the in-situ method in combination with the dealing of continuous and revolving internal interfaces. Concluding a further application of the bfTPA methodology is presented. It allows the external in-situ blocked forces of EPS systems or other products to be predicted based on internal insitu blocked forces and the BFT functions within internal receivers such as housings, for instance. Hence, the proposed approach is called “virtual component assembly”. It offers the advantage to synthesize a virtual EPS system based on the in-situ blocked forces of its components which are determined on test benches.
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Winkler, Torsten, Zaaijer Rik de, and Christian Schwab. "Energy-efficient steering systems for heavy-duty commercial vehicles." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-199785.
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Besides the braking system the steering system is one of the most important systems on vehicles. The reliability and the performance of a steering system decides on the controllability of the vehicle under normal conditions as well as emergency situations. In everyday use the characteristics, the connectivity to assistance systems and the energy efficiency of the steering system become more and more important to fulfill the increasing demands regarding fuel consumption, carbon dioxide emissions and comfort. To meet these demands, new steering systems must be implemented and new technologies have to be developed. This contribution compares different approaches regarding functionality and energy efficiency to give an indication which system is the most promising solution for future front axle steering systems as well as rear steered axles (tag- or pusher axle) on trucks.
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Ouyang, Xiaohong. "Neural network identification and control of electrical power steering systems." Thesis, University of Wolverhampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323099.
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Birgersson, Victoria, and Maximillian Lundgren-Goodman. "Dark Ages Lunar Interferometer - Deployment Rover : Propulsion and Steering Systems." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-28888.
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2030 NASA Jet Propulsion Laboratory will place an interferometer, which will workas a radio telescope, on the far side of the Moon. The interferometer uses thinpolyamide films as antennas, which are rolled out by a rover (an autonomousvehicle). The thesis covers concept generation of the propulsion and steering systemof the rover.The interferometer is to be placed on the far side of the Moon in order to ensure, asfar as possible, that it is not effected by radiation from Earth. The interferometerconsists of several polyamide films, approximately 100 meters long and one meterwide. The films are to be connected in the middle in order to form a star pattern offilm. Since the rover is to roll out these films on the surface of the Moon, it will driveback and forth to the lander to pick up the rolls. The focus in the project has been todevelop a reliable and stable system as possible so that the rover can accomplish itsmission without malfunctions. The purpose with the interferometer is to map thehydrogen gas clouds which were formed during universe’s youth (Platt, 2008).The outcome of this project is a concept indicating what the most optimal design ofwheel mount, of motor mount, of wheel and steering design may be in order to steerthe rover. The method to generate concepts used is known Fredy Olsson’s method.This is a method that has been developed at Lunds University and it has been widelyused in engineering education at Halmstad University.The four concepts developed and contributes to the whole concept for propulsion andsteering system of the rover. The four concepts developed are an all six steering, allof the six wheels can be controlled individually. Each wheel is split, or divided intwo. The motor is angle mounted and the wheel is semi-open with a slope that makesthe Moon dust fall out if it comes inside.Inspiration from previous rovers which are or have been on the Moon and Mars hasbeen useful in generating concepts. Previously used concepts are stable and reliable,which are important factors in this project. Previous theses have come to theconclusion that the chassis of the rover should be the one similar to the one used onMars Science Laboratory Curiosity and Mars Exploration Rover’s Spirit andOpportunity.The Halmstad University projects in collaboration with NASA began at HalmstadUniversity in 2013, and previous projects have developed the chassis, energy systemand the deployment mechanism of the rover. This year’s project takes intoconsideration the results from previous years since a concept of a complete roverultimately is going to be presented to NASA Jet Propulsion Laboratory.The thesis is done in collaboration with NASA Jet Propulsion Laboratory inCalifornia, USA. NASA Jet Propulsion Laboratory is the leading U.S. center forrobotic exploration of the solar system.NASA Jet Propulsion Laboratory ska 2030 placera en interferometer på månensbaksida, interferometern ska fungera som ett radioteleskop. Interferometern användersig av tunna polyamidfilmer som antenner. Dessa ska rullas ut på månens yta av enrover (ett obemannat fordon). Rapporten behandlar framtagning av koncept förstyrning och framdrivning av denna rover.Interferometern ska placeras på månens baksida för att man i så stor mån som möjligtvill undkomma strålningsstörningar från Jorden. Interferometern ska bestå av flertaletpolyamidfilmer, ca 100 meter långa och en meter breda. Filmerna skasammankopplas i en kontrollenhet som finns i mitten av det stjärnformade mönsterfilmerna läggs i. Då rovern ska placera ut dessa filmer på månens yta, ska den skaköra från och till landaren för att hämta upp rullarna. Fokus i projektet har varit attgöra ett så pålitligt stabilt system som möjligt för att rovern ska klara av att slutförasitt uppdrag utan driftstörningar. Med interferometern vill man sedan kartläggavätgasmoln som bildades i universums ungdom (Platt, 2008).Resultatet av projektet är ett koncept som visar roverns framdrivnings- ochstyrsystem, hjulupphängning, motorplacering samt hur hjuldesignen kan se ut. FredyOlssons metoder har använts för att ta fram koncept som uppfyller krav och önskemåldå denna metod har använts tidigare under utbildningen.De fyra koncept som bidrar till ett koncept för hela styr- och framdrivningssystem ärstyrning och framdrivning på roverns alla sex hjul, hjulen är designade på så vis att deär delade i två. Motorn är vinkelmonterad. Roverns hjul är semi-öppna med en kantsom är högre än det djup hjulet sjunker ner i månytan., med en sluttning inuti för attsand och damm ska rinna ut.Inspiration har kommit från tidigare rovrar som varit/är aktiva på månen och Mars dådet är beprövade koncept som visat sig vara stabila och pålitliga. Tidigareexamensarbeten har kommit fram till att det chassi som ska användas är snarlikt detsom använts på Mars Science Laboratory Curiosity och Mars Exploration Rover’sSpirit och Opportunity.Projektet började på Högskolan i Halmstad 2013 och tidigare projekt har tittat påbland annat chassit, energisystem och utplaceringsenheten. Årets projekt har tagithänsyn till resultat från tidigare år, för att ett koncept på en hel rover slutligen skakunna visas upp för NASA Jet Propulsion Laboratory.Examensarbetet är genomfört i samarbete med NASA:s Jet Propulsion Laboratory iKalifornien, USA, vilka är USA:s center för robotisk utforskning av solsystemet.
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Vetter, Jeffrey Scott. "Techniques and optimizations for high performance computational steering." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/9242.
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Drew, J. E. "The use of flexible hose to reduce pressure ripple in power steering." Thesis, University of Bath, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362556.
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Bedrossian, Nazareth Sarkis. "Steering law design for redundant single gimbal Control Movement Gyro systems." Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/14663.
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Bakolas, Efstathios. "Optimal steering for kinematic vehicles with applications to spatially distributed agents." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42873.
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The recent technological advances in the field of autonomous vehicles have resulted in a growing impetus for researchers to improve the current framework of mission planning and execution within both the military and civilian contexts. Many recent efforts towards this direction emphasize the importance of replacing the so-called monolithic paradigm, where a mission is planned, monitored, and controlled by a unique global decision maker, with a network centric paradigm, where the same mission related tasks are performed by networks of interacting decision makers (autonomous vehicles). The interest in applications involving teams of autonomous vehicles is expected to significantly grow in the near future as new paradigms for their use are constantly being proposed for a diverse spectrum of real world applications.
One promising approach to extend available techniques for addressing problems involving a single autonomous vehicle to those involving teams of autonomous vehicles is to use the concept of Voronoi diagram as a means for reducing the complexity of the multi-vehicle problem. In particular, the Voronoi diagram provides a spatial partition of the environment the team of vehicles operate in, where each element of this partition is associated with a unique vehicle from the team. The partition induces, in turn, a graph abstraction of the operating space that is in a one-to-one correspondence with the network abstraction of the team of autonomous vehicles; a fact that can provide both conceptual and analytical advantages during mission planning and execution. In this dissertation, we propose the use of a new class of Voronoi-like partitioning schemes with respect to state-dependent proximity (pseudo-) metrics rather than the Euclidean distance or other generalized distance functions, which are typically used in the literature. An important nuance here is that, in contrast to the Euclidean distance, state-dependent metrics can succinctly capture system theoretic features of each vehicle from the team (e.g., vehicle kinematics), as well as the environment-vehicle interactions, which are induced, for example, by local winds/currents. We subsequently illustrate how the proposed concept of state-dependent Voronoi-like partition can induce local control schemes for problems involving networks of spatially distributed autonomous vehicles by examining different application scenarios.
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Yavuzoglu, Emre. "Steering Laws For Control Moment Gyroscope Systems Used In Spacecraft Attitude Control." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1098441/index.pdf.
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In this thesis, the kinematic properties of Single Gimballed Control Moment Gyroscopes (SGCMGs) are investigated. Singularity phenomenon inherent to them is explained. Furthermore, existing steering laws with their derivations are given.
A novel steering law is developed that may provide singularity avoidance or may be used for quick transition through a singularity with small torque errors. To avoid singularity angular momentum trajectory of the maneuver is to be simulated in advance for the calculation of singularity free gimbal histories. The steering law, besides accurately generating required torques, also pushes the system to follow trajectories closely if there is a small difference between the planned and the realized momentum histories. Thus, it may be used in a feedback system. Also presented are number of approaches for singularity avoidance or quick transition through a singularity. The application of these ideas to the feedback controlled spacecraft is also presented. Existing steering laws and the proposed method are compared through computer simulations. It is shown that the proposed steering law is very effective in singularity avoidance and quick transition through singularities. Furthermore, the approach is demonstrated to be repeatable even singularity is encountered.
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Wendel, Michael W. "The effects of shipboard steering machinery dynamics on rudder roll stabilization systems." Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/27019.
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Approved for public release; distribution is unlimitedThe surface ship rolling motion equation is modeled as a second order system, with a natural frequency of con — 0.4/.sec and a dimcnsionless damping ratio of £ = 0.08. The model is subjected to a random forcing function, which has a Gaussian probability distribution and can be considered as "white noise", and placed into State-Space form. State variable feedback of roll rate is applied and the system discretized to match digital control. Roll angle time histories are developed for a range of feedback gains and compared. Additionally, steering machinery dynamics are modeled by a first order system and time constants varied to determine the effects of rudder dynamics on the feedback system.
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Fu, Zhenhai. "Substrate-guided wave true-time delay network for phased array antenna steering /." Full text (PDF) from UMI/Dissertation Abstracts International, 2000. http://wwwlib.umi.com/cr/utexas/fullcit?p9992792.
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Bansal, Mayur. "DIGITAL CONTROL BOARD FOR PHASED ARRAY ANTENNA BEAM STEERING IN ADAPTIVE COMMUNICATION APPLICATIONS." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1113.
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The application of adaptive communication techniques for mobile communications has attracted considerable interest in the last decade. One example of these techniques is spatial filtering through planar antenna array beam forming.
This thesis describes the development of a digital system that adaptively controls a phased array antenna. The radiating structure of the phased antenna array is tetrahedral-shaped and contains four antenna elements on each of its three faces. The overall system comprises of a digital control board with an external computer interface, an RF control board, and the phased antenna array. The RF controls the main lobe direction on the phased array antenna. This thesis describes the design and implementation of the digital control board.
The digital control board`s primary responsibilities are implementing inter- faces between the external computer and the RF board, which results in two operational modes: the MATLAB graphical user interface (GUI) mode and the adaptive receive mode. The GUI mode allows users to input parameters that provide interactive control of the phased antenna array by interfacing with an external computer and the RF control board. The adaptive receive mode im- plements an algorithm for an adaptive receive station. This algorithm uses a 58-point scanning technique that locates the maximum receive power direction.
Test results show that the digital control board successfully manages the RF board control voltage with an nominal error of less than 1%, which subsequently allows for precise control of the antenna`s active face. Additionally, testing of the GUI demonstrated the successful interactive application of various system control parameters.
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Magnusson, Filip. "Evaluating Deep Learning Algorithms for Steering an Autonomous Vehicle." Thesis, Linköpings universitet, Programvara och system, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-153450.
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With self-driving cars on the horizon, vehicle autonomy and its problems is a hot topic. In this study we are using convolutional neural networks to make a robot car avoid obstacles. The robot car has a monocular camera, and our approach is to use the images taken by the camera as input, and then output a steering command. Using this method the car is to avoid any object in front of it. In order to lower the amount of training data we use models that are pretrained on ImageNet, a large image database containing millions of images. The model are then trained on our own dataset, which contains of images taken directly by the robot car while driving around. The images are then labeled with the steering command used while taking the image. While training we experiment with using different amounts of frozen layers. A frozen layer is a layer that has been pretrained on ImageNet, but are not trained on our dataset. The Xception, MobileNet and VGG16 architectures are tested and compared to each other. We find that a lower amount of frozen layer produces better results, and our best model, which used the Xception architecture, achieved 81.19% accuracy on our test set. During a qualitative test the car avoid collisions 78.57% of the time.
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Na, Xiaoxiang. "Game theoretical modelling of a driver's interaction with active steering." Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708392.
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YANG, GEPENG, and JONATHAN ADOLFSSON. "Modular Scaled Development Platform for Steering Algorithms using LEGO Mindstorms." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-263166.
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The topic of the thesis is to build physically similar systems to simulate behaviors of real-life heavy-duty vehicles using LEGO Mindstorms as hardware platform and Buckingham π theorem as theoretical basis for the parameter scaling. The thesis work includes software and hardware system design and theoretical research in order to prove a newly proposed concept: Using LEGO to build a scaled model of real-life vehicles with specific similar physical properties. To implement the work described above, scaled models were built with LEGO and a software and hardware system was developed for controlling the scaled model. Tests were performed both on real-life vehicles and scaled models. A generalized mathematical model for the vehicle was derived in order to interpret the behaviors of the vehicle in a scientific way. Then, test results of both real-life vehicles and the corresponding scaled model were compared with the mathematical model in order to investigate if they have similar behaviors. Finally it was concluded that the scaled model built with LEGO Mindstorms combined with Buckingham π theorem could calculate the speed and turning radius of the physically similar real-life vehicle with an average accuracy of 94.68% within low speed, conservatively speaking. For further investigation and research, similar research could be performed with higher speeds to generalize the conclusions and results.Uppsatsen ämnar till att bygga ett fysiskt likvärdigt system, som simulerar beteendet av verkliga tunga fordon, med LEGO Mindstorms som hårdvaruplattform och med Buckingham П teoremet som teoretisk grund from skalning av parametrar. Arbetet inkluderar mjukvaru- och hårdvarusystemdesign samt teoretisk forskning för att kunna bevisa ett nyligen föreslaget koncept: Att använda LEGO för att bygga en skalad modell av verkliga fordon med specifika likartade fysiska egenskaper. För att implementera det ovan föreslagna arbetet, byggdes skalade modeller i LEGO samt ett kombinerat hård- och mjukvarusystem för att styra den skalade modellen. Tester utfördes på både riktiga lastbilar samt de skalade modellerna. För att kunna identifiera parametrar samt simulera och tyda fordonens beteende så adapterades en generell matematisk modell. Testresultaten för på verkliga samt motsvarande skalade modeller jämfördes med den matematiska modellen för att påvisa om beteendet är likartat. Till sist drogs slutsatsen att den skalade modellen bygg med LEGO Mindstorms och parameterskalad med hjälp av Buckingham П teoremet kunde beräkna skalningsfaktorn av hastighet samt svängradie för det fysiskt likartade fordonet med en tillförlitlighet på 94.68%, konservativt räknat. Detta gäller för låga hastigheter och som fortsatt forskning skulle en liknande studie med starkare och snabbare motorer genomföras för att generalisera slutsatserna och resultaten.
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Lee, Jong-Nyun. "Design sensitivity analysis of multibody systems with special reference to four-wheel steering." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/185963.
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Sensitivity analysis methods are investigated for the optimal design of multibody systems. In order to overcome the shortcomings inherent in existing methods, a "mixed" method is developed. The beneficial features of the finite difference and the direct differentiation methods, and equations of motion in the joint coordinates are employed in this method. As a realistic application of the sensitivity analysis, a Four-Wheel-Steering vehicle with complete suspension systems and comprehensive analytical tire model is implemented. This model keeps full nonlinearity in the governing equations of motion for accuracy, and it is simulated using an existing general-purpose multibody dynamics simulation package. However, by using the transient dynamic analysis of the nonlinear model, optimal design parameters are dependent on driving scenarios. Therefore, the transient behavior of the system is represented by a series of steady state configurations. Hence, a steady state analysis procedure which finds a steady state configuration from an arbitrary initial condition is developed. By using the steady state analysis and the sensitivity analysis, the optimal steering ratios between the angles of the front and the rear wheels are obtained over various driving conditions. A steering control strategy is developed for the vehicle simulation to follow a prescribed path. Finally, the simulation results using the optimal steering ratio are compared against the results of the conventional two-wheel steering and the steering ratio based on the linear bicycle model.
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Sturm, M. "Identification and quantification of transient structure-borne sound sources in electrical steering systems." Thesis, University of Salford, 2014. http://usir.salford.ac.uk/30761/.
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During driving on rough roads, rattle noise may emanate from (electric power) rack-and-pinion steering gears as a result of reverse feedback from the road. This project is in collaboration with a German steering system manufacturer and aims to develop a methodology facilitating identification and quantification of transient structure-borne sound sources within electrical steering systems. To achieve this aim, a conceptual source-path-receiver model has been developed that discloses the theoretical locations and associated mechanisms of all possible transient sound sources inside the steering gear. This information forms the basis for a subsequent measurement step which is required to experimentally quantify the strength of each individual source. The measurement approach is based on a time domain equivalent of the in-situ blocked force method; thus facilitating independent source characterisation on the fully assembled structure. The time domain (TD) approach relies on a robust inversion routine that uses an adaptive algorithm to simultaneously reconstruct multi-channel (blocked) force signatures from operational responses and the corresponding impulse response functions both measured (in-situ) on the (assembled) structure. The TD inversion routine is derived from the least mean square (LMS) algorithm which is widely used in adaptive filter design. The accuracy and sensitivity of the TD inversion routine is elaborated and compared to the standard frequency domain inverse method using simple numerical examples. Its general applicability for sophisticated technical structures is evaluated by example of an electric powered steering system being subjected to artificial excitation. The use of the TD approach for characterisation of transient structure-borne sound sources based on the blocked force method is discussed and different procedures to improve the force estimation accuracy are proposed. These procedures can be classified into methods that (i) help to evaluate the quality of pre-measured frequency response functions (FRFs) which are required to set up the (inverse) system model, (ii) measurement routines that may help to improve future FRF measurements conducted in-situ, i.e. whilst the steering gear is connected to a special rattling test bench, (iii) correction strategies to separate contributions from known (external) structure-borne sound sources different from the desired (internal) rattling sources and (iv) criteria that in theory allow for monitoring the performance of the iterative TD inversion routine precisely. Finally, the developed methodology is used to identify and quantify rattle sources within a steering system under realistic testing conditions.
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Shoemaker, Adam Kenneth. "Nonholonomic Control Utilizing Kinematic Constraints of Differential and Ackermann Steering Based Platforms." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/78053.
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A nonholonomic tracking controller is designed and adapted to work with both differential steering and Ackermann steering based platforms whose dynamics are represented using a unicycle model. The goal of this work is to find a relatively simple approach that offers a practical alternative to bulky and expensive algorithms, but still bolsters applicability where many other lightweight algorithms are too lax. The hope is that this alternative will offer a straightforward approach for groups interested in autonomous vehicle research but who do not have the resources or personnel to implement more complex solutions. In the first phase of this work, saturation constraints based on differential drive kinematics are added to ensure that the vehicle behaves intuitively and does not exceed user defined limitations. A new strategy for mapping commands back into a viable envelope is introduced, and the restrictions are accounted for using Lyapunov stability criteria. This stage of work is validated through simulation and experimentation. Following the development of differential drive methods, similar techniques are applied to Ackermann steering kinematic constraints. An additional saturation algorithm is presented, which likewise is accounted for using Lyapunov stability criteria. As with the differential case, the Ackermann design is validated through simulation and experimentation. Overall, the results presented in this work demonstrate that the developed algorithms show significant promise and offer a lightweight, practical solution to the problem of vehicle tracking control.Master of Science
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Lin, Cynthia S. B. Massachusetts Institute of Technology. "Feasibility of using power steering pumps in small-scale solar thermal electric power systems." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/43016.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (leaves 59-60).
The goal of this study was to determine performance curves for a variety of positive displacement pumps in order to select an efficient and low cost option for use as a boiler feed pump in a 1-kWe organic Rankine cycle (ORC) system built by the Solar Turbine Group in Lesotho. The pumps tested included OEM plunger and piston pumps, and rotary vane-type power steering pumps purchased from a junk yard. Motor speed and torque were measured at different flow rates to determine the power consumed to move fluid in the prescribed pressure regime. The test station was designed to pump deionized water; it was intended that measurements and calculations would then be non-dimensionalized and used to predict the ORC working fluid's properties. Unfortunately, deionized water caused the power steering pump shafts to seize; the efficiencies were below anticipated and the pumps were unable to operate under the specified pressures. It was discovered, after WD-40 was added to the water, that power steering pumps performed best when moving fluids with more lubricity. The optimal pump was selected based on how the pump efficiency affected the overall ORC system efficiency, defined as the electrical work output divided by the heat input, and the net electric power output. Power steering pumps achieved efficiencies between 34%-54% under the desired ORC operating conditions with water-oil emulsion as the working fluid. For that pump efficiency range, the overall solar thermal electric ORC system efficiency would be 7.4%-8.5% and the overall system cost would be USD 4.59-5.27 per installed Watt. Made specifically for pumping hydroflurorcarbons, the working fluid used in STG's ORC, the OEM Dynex pump exhibited poorer performance than predicted. The pump efficiency of 31% gave a system efficiency of 7.1% and a cost of USD 6.40 per installed Watt. The OEM water piston and plunger pumps made by Hypro achieved efficiencies of 70% and 81%, respectively, under the same ORC operating conditions described above.
(cont) For those pump efficiencies, the overall system efficiencies would be 9.0% and 9.2% and the costs would be USD 4.58 and 4.63 per installed Watt, respectively. The most optimal pump is the HyproPiston pump; although it costs nearly six times that of a power steering pump, the overall system cost is lower when normalized over the power output.
by Cynthia Lin.
S.B.
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Murphy, Kris. "A THEORY OF STEERING COMMITTEE CAPABILITIES FOR IMPLEMENTING LARGE SCALE ENTERPRISE-WIDE INFORMATION SYSTEMS." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1458218732.
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Bae, Kyung Kyoon. "Analytical Framework for the Performance Analysis of Multiple Antenna Systems." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/29212.
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There has been great interest in antenna array processing (diversity, beamforming, null steering, and spatial multiplexing) to enhance the received signal quality and the capacity of
wireless communications systems. However, in order to properly exploit the characteristics of different array processing techniques, understanding trade-offs among different techniques and parametric investigation, which offers an insight as to what parameters determine system performance under different situations
is necessary. In this study, we present analytical framework which can facilitate the performance analysis of systems with antenna
array.
Five original contributions to the performance analysis of antenna array processing are presented in this study. First, we present theoretical outage probability of a system equipped with an array which suppresses a few dominant interering signals in TDMA cellular networks when the fading statistics of interfering
signals are independent but non-identically distributed. Most of the related previous works assumed either independent and identically distributed fading statistics among cochannel
interferences (CCI) or Rayleigh fading when CCI signals are subject to i.n.d. fading statistics. Secondly, the performance of multi-branch predetection equal gain combiner for different
modulation techniques in equally correlated Nakagami-$m$ fading is presented through analytical analysis. Specifically, the
characteristic function (CHF) and the moment generating function (MGF) of EGC output with correlated inputs are derived and used to evaluate the average symbol error probability (ASEP) and the outage probability performance, respectively. Thirdly, we derived analytical expression which can be used to analyze the
performance of different types of diversity techniques in equally correlated Nakagami-m or Rice fading channels. Fourthly, asymptotic analysis on different types of diversity combiners in generalized fading channels is presented in a unifying way. Finally, we investigate and present the impact of transmit
diversity at handsets on the reverse link DS/CDMA systems in terms of capacity and coverage over generalized fading channels through analytical approaches. Then, we validate the analytical results with simulation results and investigate practical issues which are hard to capture through analytical analysis using system level
simulator we developed.
Although we have mainly focused on applying the analytical framework we have derived in this work to the performance analysis of physical layer algorithms such as spatial diversity and
adaptive null steering, the framework can be extended to assist the analysis and design of wireless communication systems such as,
to name a few, distributed multiple input multiple output (MIMO) system in cooperative wireless networks, multipath routing protocol analysis in wireless fading channels, and antenna
selection problems in MIMO system.Ph. D.
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Khawar, Awais. "Spectrum Sharing between Radar and Communication Systems." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/54548.
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Radio frequency spectrum is a scarce natural resource that is utilized for many services including surveillance, navigation, communication, and broadcasting. Recent years have seen tremendous growth in use of spectrum especially by commercial cellular operators. As a result, cellular operators are experiencing a shortage of radio spectrum to meet bandwidth demands of users. Spectrum sharing is a promising approach to solve the problem of spectrum congestion as it allows cellular operators access to more spectrum in order to satisfy the ever growing bandwidth demands of commercial users. The US spectrum regulatory bodies are working on an initiative to share 150 MHz of spectrum, held by federal agencies, in the 3.5 GHz band with commercial wireless operators. This band is primarily used by radar systems that are critical to national defense. Field tests have shown that spectrum sharing between radars and communication systems require large separation distance in order to protect them from harmful interference. Thus, novel methods are required to ensure spectrum sharing between the two systems without the need of large protection distances.
In order to efficiently share spectrum between radars and communication systems at the same time and in the same geographical area, a novel method is proposed that transforms radar signal in such a way that it does not interfere with communication systems. This is accomplished by projecting the radar signal onto null space of the wireless channel between radar and communication system. In order to understand the effects of the proposed sharing mechanism -- in urban, sub-urban, and littoral areas -- new channel models, specifically, two- and three-dimensional channel models are designed that capture azimuth and elevation angles of communication systems and helps in placing accurate nulls. In addition, interference coming from communication systems into radar receivers is analyzed and radar performance is accessed. Using this information, resource allocation schemes are designed for communication systems that take advantage of the carrier aggregation feature of the LTE-Advanced systems. This further helps in dynamic sharing of spectrum between radars and communication systems. The proposed signal projection approach not only meets radar objectives but also meets spectrum sharing objectives. However, there is a trade-off as signal projection results in some performance degradation for radars. Performance metrics such as probability of target detection, Cramer Rao bound and maximum likelihood estimate of target's angle of arrival, and beampattern of radar are studied for performance degradation. The results show minimal degradation in radar performance and reduction in exclusion zones, thus, showing the efficacy of the proposed approach.Ph. D.
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Bittle, Charles C. "Linearity and monotonicity of a 10-bit, 125 MHz, segmented current steering digital to analog converter." Thesis, University of North Texas, 2000. https://digital.library.unt.edu/ark:/67531/metadc2541/.
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The purpose of this research is to determine the linearity and monotonicity of the THS5651IDW digital to analog converter (DAC), a prototype of the future Texas Instruments TLV5651, 10-bit, 125 MHz communication DAC. Testing was conducted at the Texas Instruments facility on Forest Lane, Dallas, Texas. Texas Instruments provided test equipment, software and laboratory space to obtain test data. Analysis of the data found the DAC to be monotonic since the magnitude of the differential nonlinearity (DNL) was less than ± 1 least significant bit (LSB) and the integral nonlinearity (INL) was less than ± 0.5 LSB. The study also showed that the DAC has primarily negative DNL although the DNL is well within the desired specification.
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GHAZARIAN, DANIEL. "Estimating the energy consumption of steering assist systems in commercial hybrid electric vehicles : A basis for utilization strategies." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-299354.
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The commercial vehicle manufacturer Scania CV AB has introduced a new steering functionality called Redundant Brake Steering (RBS) in vehicles with batteries as energy storage, i.e. hybrid-electric and electric vehicles. Although, the primary steering system in Scania’s electrified vehicles consists of an electrohydraulic steering system (EHS) and an electrical active steering system (EAS). The purpose of introducing RBS is to facilitate the implementation of the EAS as a secondary steering system according to current laws. Consequently, a major benefit is that the conventional back-up hydraulic steering system can be removed. By replacing the back-up system with the active steering system and RBS an entire auxiliary system in the vehicle is eliminated. One of the main ambitions of this study has been to investigate whether the new steering functionality could lead to reduced energy consumption related to steering systems. The approach in this thesis included a literature study of steering systems, brake-steering concepts and available vehicle data to establish methods to quantify the energy consumption of the involved systems. The methods were used to develop a numerical model in the software Matlab which could use collected vehicle data to estimate the energy consumption of the steering systems. To facilitate the data collection a case study was performed using a plug-in hybrid electric vehicle (PHEV) at Scania’s test track in Södertälje, Sweden. The results suggested that the combination of EAS and RBS has potential to assist as primary steering as the energy consumption related to steering could be decreased by up to 90.6%. Also, the results indicated that the load on the vehicle’s electrical circuit could be reduced significantly, while the main drawback is increased steering effort by the driver.Lastbils -och busstillverkaren Scania CV AB har nyligen introducerat ett system vid namnet Redundant Brake Steering (RBS) för elektrifierade fordon. Det primära styrsystemet i dessa fordon består av ett elektro-hydraliskt system (EHS) samt ett elektriskt aktivt styrsystem (EAS). Bakgrunden till att introducera RBS har varit grundat i att kunna implementera EAS som sekundärt styrsystem för att tillfredställa nuvarande lagkrav. Utfallet har blivit att det sekundära hydrauliska styrsystemet har kunnat ersättas med bromsstyrningssystem (RBS) samt EAS. Den grundläggande ambitionen för denna studie har varit at utforska ifall det nya bromsstyrningssystemet kan bidra till minskad energiförbrukning av fordonets styrsystem. Denna studie har bland annat innefattat en litteraturstudie av styrsystem, koncept som berör bromsstyrning samt tillgänglig fordonsdata för att kunna utveckla beräkningsmetoder av energiförbrukning av respektive system. Metoderna användes för att utveckla en beräkningsmodell i mjukvaran Matlab som med hjälp av fordonsdata kunde uppskatta energiförbrukningen av styrsystemen. Fordonstester utfördes i en fallstudie för att kunna samla in mätningar av fordonsdata. Detta gjordes med hjälp av ett plug-in hybrid fordon (PHEV) på Scania’s provbana i Södertälje, Sverige. Resultaten indikerade att en kombination av EAS och RBS har potential att bistå som primärt styrsystem sett till energiförbrukningen vilken kunde reduceras med upp till 90.6%. Vidare visade resultaten att påfrestningen på fordonets elektriska system kunde minskas, dock med nackdelen att förarens ansträngning ökar.
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Kruger, Iwan Carel. "An aircraft based emulation platform and control model for LEO satellite antenna beam steering." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5200.
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Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: A joint project between the KU Leuven and Stellenbosch Universities was at the time of this thesis underway to develop a space borne electronically beam steerable antenna and the associated ground-space segments. This thesis covers the development of an aircraft based satellite emulator to facilitate convenient aircraft based testing of an antenna array, intended for low earth orbit satellite deployment and subsystems to control the antenna array. A flight strategy is developed to emulate such a satellite pass as best possible, with the strategy implemented in software on in-flight PC hardware. A full interface between the aircraft avionics and satellite bus system has been developed to enable generation of the required antenna steering commands and to create a satellite bus image to the payload. Successful test results are presented, as obtained from the actual aircraft ight simulator. The thesis describes the successful development and testing of a low altitude flight test strategy for certain satellite borne systems, as a cost-effective and realistic interim step to actual and very expensive space flight testing.
AFRIKAANSE OPSOMMING: 'n Gesamentlike projek deur KU Leuven en Stellenbosch Universiteit was tydens die verloop van hierdie tesis besig met die ontwikkeling om 'n ruimte gebaseerde elektroniese straal beheerde antenna en geassosieerde substelsels daar te stel. Hierdie tesis handel oor die ontwikkeling van 'n vliegtuig gebaseerde satelliet emulator om die toetsing van 'n elektroniese stuurbare antenna, wat bedoel is vir 'n lae aardse wentelbaan, te fasiliteer en die ontwikkeling van substelsels wat die stuurbare antenna beheer. 'n Vlug strategie is ontwikkel om so 'n satelliet wentelbaan so na as moontlik te emuleer. Die strategie word dan geïmplementeer in die sagteware van die aanboord vlug rekenaar. 'n Intervlak tussen die vliegtuig instrumente en satellietbus is ontwikkel om die generering van die nodinge instruksies te fasiliteer en om 'n virtuele satellietbus vir die res van die satelliet stelsel te skep. Suksesvolle toets resultate word getoon wat met behulp van 'n vliegtuig simulator verkry is. Die tesis beskryf die suksesvolle ontwikkeling en toetsing van 'n lae vlugtoets strategie vir satelliet stelsels, as 'n koste effektiewe en realistiese tussenstap, tot baie duur ruimte vlugtoetsing.
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Andrade, Rayssa Bruzaca de. "An optical parametric oscillator for a light- atomic media interface." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-18062018-052437/.
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In this work, we discuss a description of quantum properties of light beams produced by an Optical Parametric Oscillator (OPO) above threshold, pumped by a 780 nm Titanium Sapphire laser, resonant with the D2 line of Rb with a noise spectrum of a coherent beam. The twin beams have wavelengths around 1560nm, in the telecommunication band. The states emitted by the OPO under study are approximately Gaussian (1), which allows us to describe them in terms of first and second order moments. As we analyze the noise spectrum of the fluctuations of each beam, the first order moments are null, which allows us to describe the state of the system in terms of a covariance matrix. We present the behavior of the noise spectrum and the correlations between the reflected pump, signal and idler beams. In addition, we applied different entanglement criteria to study the system. We present a prediction of the bipartite entanglement using Duan criterion (2). For tripartite correlations, we use the Furusawa criterion (3). We performed a study of bipartition pump and sum quadrature. As well, we applied the PPT criterion (4) for continuous variables, independently transposing each beam under study. The PPT criterion is necessary and sufficient to demonstrate entanglement between bipartitions for Gaussian states. In order to explore the behavior of the system using the steering criterion in the model developed by Reid (5), we theoretically study the criterion of inference for bipartite quadratures: between the twin beams or between one of the twin beams and the pump beam. In addition, we analyzed the inference between the three modes, through the bipartition pump mode and combination of sum quadrature of the twin beams. We develop a quantum teleportation protocol of a coherent input state, composed by the Titanium Sapphire beam whose Bell measurement is performed using the pump reflected by the OPO as an entangled state for the signal and idler beams as a first possibility to implement the protocol. Furthermore, we propose a protocol in which the signal beam assists in the process of teleportation. Thus, the fidelity of the system increases and exceeds the limit of non-cloning. We will describe the first measurements of correlations between the beams emitted by the OPO for this system. The tripartite entanglement characterization is the first step in the implementation of quantum optical protocols using a source of entangled states that is compatible with both Rubidium atomic systems and the telecommunications region, thus forming a quantum network.Nesse trabalho apresentamos uma descrição das propriedades quânticas dos feixes de luz produzidos por um Oscilador Paramétrico Ótico (OPO) acima do limiar, bombeado por um laser de Titânio Safira com comprimento de onda de 780nm, linha D2 do Rb, com espectro de ruído de um feixe coerente. Os feixes gêmeos possuem comprimentos de onda na região de 1560 nm que compreende a janela de transmissão de fibras óticas. Os estados emitidos pelo OPO em estudo são aproximadamente gaussianos (1), o que nos permite descrevê-los em termos de momentos de primeira e segunda ordem. Como analisamos o espectro de ruído das flutuações de cada feixe, os momentos de primeira ordem são nulos, o que nos permite descrever o estado do sistema em termos de uma matriz de covariância. Apresentamos então o comportamento do espectro de ruído e das correlações entre os feixes de bombeio refletido, sinal e complementar. Ademais, aplicamos diferentes critérios de emaranhamento para estudar o sistema. Apresentamos uma previsão do emaranhamento bipartido utilizando o critério de Duan (2). Para as correlações tripartidas, utilizamos o critério de Furusawa (3). Realizamos um estudo da bipartição bombeio e quadratura soma. E, aplicamos o critério PPT para variáveis contínuas (4), transpondo independente cada feixe em estudo. O critério PPT é necessário e suficiente para demonstrar emaranhamento entre bipartições para estados gaussianos. Com o objetivo de explorar qual o comportamento do sistema frente ao critério de \"steering\" no modelo desenvolvido por Reid (5), estudamos teoricamente o critério de inferência para quadraturas bipartidas: entre os feixes gêmeos ou entre um dos feixes gêmeos e o feixe de bombeio. Finalizamos essa análise caracterizando a inferência entre os três modos, através da bipartição modo do bombeio e combinação das quadraturas soma dos feixes gêmeos. Apresentamos a formulação de um protocolo de teletransporte quântico de um estado coerente de entrada formado pelo feixe do Titânio Safira, cuja medida de Bell é realizada utilizando o bombeio refletido pelo OPO como estado emaranhado para os feixes sinal e complementar, como uma primeira possibilidade de implementar o protocolo. Também propomos um protocolo em que o feixe sinal auxilia no processo de teleportação. Dessa forma, a fidelidade do sistema aumenta e supera o limite da não clonagem. Descreveremos as primeiras medidas de correlações entre os feixes emitidos pelo OPO para esse sistema. A caracterização de emaranhamento tripartido nessa nova configuração é o primeiro passo para a implementação de protocolos de ótica quântica utilizando uma fonte de estados emaranhados que é compatível tanto com sistemas atômicos de Rubídio quanto com a região de telecomunicações, formando assim uma rede quântica de transferência e aprisionamento de informação.
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Karimdady, Sharifabad Farnaz. "Covariance Modeling and Space-Time Coding for MIMO systems." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3510.
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The full spatial covariance matrix of the multiple input multiple-output (MIMO) channel is an important quantity in channel modeling, communication system signal processing, and performance analysis, and therefore this matrix forms the heart of the research outlined in this dissertation. The work begins with an investigation of a generalized framework for computing the full MIMO spatial covariance based on the power angular spectrum (PAS) of the multipath field and the transmit and receive antenna element radiation patterns. For the case of uniform linear arrays and when the PAS clusters satisfy uniform, truncated Gaussian, or truncated Laplacian distributions, a series expansion is used to allow analytic evaluation of the required integrals in the formulation. The study also demonstrates the validity of some simplifying assumptions used to reduce the complexity of the covariance computation by applying the technique to ray tracing data as well as considers an analysis of the convergence properties of the series when computed using a finite number of terms. The insights and tools obtained from this covariance analysis are then used to develop a general approach for constructing MIMO transmit and receive beamforming vectors based on the full spatial covariance. While transmit and receive beamforming for the MIMO channel is a well-studied topic, when the transmit precoding is based on channel covariance information, developing near-optimal transmit and receive beamformers when the receiver is constrained to use linear processing remains an unsolved problem. This iterative beamforming algorithm presented here can accommodate different types of available channel information and receiver capabilities as well as either a sum power constraint or a per-antenna power constraint. While the latter is more realistic, construction of the optimal transmit precoder is less understood for this constraint. Simulation results based on measured channels demonstrate that the approach generates beamformer solutions whose performance rivals that achieved for an optimal nonlinear receiver architecture.
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Baio, Fábio Henrique Rojo [UNESP]. "Metodologia para ensaio de sistemas de direcionamento via satélite em percursos retos e curvos." Universidade Estadual Paulista (UNESP), 2005. http://hdl.handle.net/11449/101789.
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baio_fhr_dr_botfca.pdf: 1752320 bytes, checksum: 5f5df0d06b9f3f74819e53ed595378e2 (MD5)Universidade Estadual Paulista (UNESP)
O uso do Sistema de Posicionamento Global (GPS) em uma propriedade agrícola não está limitado ao monitoramento georreferenciado de fatores produtivos, mas cada vez mais esta tecnologia está sendo utilizada como um equipamento disponível dentro da propriedade e que deve ser utilizada o máximo possível para a diluição do seu custo. Uma utilização cotidiana desta tecnologia é em sistemas de direcionamento via satélite. No entanto, ensaios destes sistemas de direcionamento operando em curva estão ainda no início. Poucas também são as informações relacionadas à análise de custo de investimento desta tecnologia. Os objetivos deste trabalho foram desenvolver uma metodologia de campo para ensaios de sistemas de direcionamento via satélite e/ou convencionais em sua utilização terrestre operando em reta e em curva, avaliar a acurácia de diferentes sistemas de orientação seguindo a metodologia desenvolvida e realizar uma breve análise de investimento para aquisição de um sistema de direcionamento via satélite. Para tanto, foram realizados quatro ensaios de campo em que foram ensaiados sete sistemas de direcionamento por barra de luz, um sistema de auto-direcionamento, um sistema de direcionamento por monitor eletrônico, um sistema de direcionamento por cabo-de-aço e um sistema de orientação por marcador de espuma. Em cada ensaio de campo foi aplicada a mesma metodologia desenvolvida para avaliação da acurácia destes sistemas de direcionamento. Esta metodologia se baseou na mensuração direta em campo dos desvios dos alinhamentos orientados pelos sistemas de direcionamento em relação ao alinhamento programado. Os ensaios foram realizados em reta e em curva. A metodologia de campo apresentada neste trabalho para ensaios de sistemas de direcionamento pôde ser aplicada com sucesso...
The use of the Global Positioning System (GPS) in a farm is not limited to monitor productive factors involved on the yield production, but the GPS have been used as equipment available into the farm that can be used to another issues and it must be used a lot into the farm to dilute the initial cost. A daily use of this technology is on steering systems. However, we do not have results of field tests of these steering systems operating in curve. Few also are the information related to the cost analysis of investments on this technology. The purposes of this work were develop a field test methodology to evaluate the accuracy of conventional steering systems and/or satellites steering systems operating in straight line or curve operations, evaluate the accuracy of several steering systems according to the developed methodology and perform a brief cost analysis to buy a satellite steering system. Four field test evaluations were performed where were evaluated seven light bar steering systems, one auto-steering system, one steering system operated by an electronic monitor, a steering system operated by a steel cable and a system oriented by a foam marker. The same developed methodology was applied on these four field test. This developed methodology was based on measure the steering error compared to the programmed alignment directly on the field, where an operator was guided by the evaluated steering system. The tests were made in straight line and curve operations. The field methodology presented in this work was successful. The advantage of this methodology is the possibility of reflection of all factors involved in the errors and the possibility of the errors measured in the field directly by the final user...(Complete abstract click electronic access below)
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Engel, Thomas. "Digitalization and Big Data from the John Deere Perspective." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-211654.
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Larsson, Veronique. "Procurement of the vacuum waste collection systems : The cases of Hammarby Sjöstad and Stockholm Royal Seaport." Thesis, Stockholms universitet, Kulturgeografiska institutionen, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-91410.
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Badeda, Julia [Verfasser], Dirk Uwe [Akademischer Betreuer] Sauer, and Antonello [Akademischer Betreuer] Monti. "Modeling and steering of multi-use operation with uninterruptible power supply systems utilizing the example of lead-acid batteries / Julia Badeda ; Dirk Uwe Sauer, Antonello Monti." Aachen : Universitätsbibliothek der RWTH Aachen, 2019. http://d-nb.info/121517148X/34.
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Eck, James Arthur. "Compact Antennas and Arrays for Unmanned Air Systems." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/4297.
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A simple and novel dual-CP printed antenna is modelled and measured. The patch antennais small and achieves a low axial ratio without quadrature feeding. The measured pattern showsaxial ratio pattern squinting over frequency. Possible methods of improving the individual element are discussed, as well as an array technique for improving the axial ratio bandwidth. Three endfire printed antenna structures are designed, analyzed, and compared. The comparison includes an analysis of costs of production for the antenna structures in addition to their performance parameters. This analysis concludes that cost of materials primarily reduces the size of antennas for a given gain and bandwidth. An antenna stucture with an annular beam pattern for down-looking navigational radar is proposed. The antenna uses sub-wavelength grating techniques from optics to achieve a highly directive planar reflector which is used as a ground plane for a monopole. A fan-beam array element is fabricated for use in a digitally steered receive array for obstacle avoidance radar. The steered beam pattern is observed. The element-dependent phase shifts for a homodyned signal in particular are explored as to their impact on beam steering.
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Baio, Fábio Henrique Rojo 1975. "Metodologia para ensaio de sistemas de direcionamento via satélite em percursos retos e curvos /." Botucatu : [s.n.], 2005. http://hdl.handle.net/11449/101789.
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Orientador: Ulisses Rocha AntuniassiBanca: Edivaldo Domingues Velini
Banca: José Armando Furlani Junior
Banca: José Paulo Molin
Banca: Otávio Jorge G. Abi Saab
Resumo: O uso do Sistema de Posicionamento Global (GPS) em uma propriedade agrícola não está limitado ao monitoramento georreferenciado de fatores produtivos, mas cada vez mais esta tecnologia está sendo utilizada como um equipamento disponível dentro da propriedade e que deve ser utilizada o máximo possível para a diluição do seu custo. Uma utilização cotidiana desta tecnologia é em sistemas de direcionamento via satélite. No entanto, ensaios destes sistemas de direcionamento operando em curva estão ainda no início. Poucas também são as informações relacionadas à análise de custo de investimento desta tecnologia. Os objetivos deste trabalho foram desenvolver uma metodologia de campo para ensaios de sistemas de direcionamento via satélite e/ou convencionais em sua utilização terrestre operando em reta e em curva, avaliar a acurácia de diferentes sistemas de orientação seguindo a metodologia desenvolvida e realizar uma breve análise de investimento para aquisição de um sistema de direcionamento via satélite. Para tanto, foram realizados quatro ensaios de campo em que foram ensaiados sete sistemas de direcionamento por barra de luz, um sistema de auto-direcionamento, um sistema de direcionamento por monitor eletrônico, um sistema de direcionamento por cabo-de-aço e um sistema de orientação por marcador de espuma. Em cada ensaio de campo foi aplicada a mesma metodologia desenvolvida para avaliação da acurácia destes sistemas de direcionamento. Esta metodologia se baseou na mensuração direta em campo dos desvios dos alinhamentos orientados pelos sistemas de direcionamento em relação ao alinhamento programado. Os ensaios foram realizados em reta e em curva. A metodologia de campo apresentada neste trabalho para ensaios de sistemas de direcionamento pôde ser aplicada com sucesso...(Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The use of the Global Positioning System (GPS) in a farm is not limited to monitor productive factors involved on the yield production, but the GPS have been used as equipment available into the farm that can be used to another issues and it must be used a lot into the farm to dilute the initial cost. A daily use of this technology is on steering systems. However, we do not have results of field tests of these steering systems operating in curve. Few also are the information related to the cost analysis of investments on this technology. The purposes of this work were develop a field test methodology to evaluate the accuracy of conventional steering systems and/or satellites steering systems operating in straight line or curve operations, evaluate the accuracy of several steering systems according to the developed methodology and perform a brief cost analysis to buy a satellite steering system. Four field test evaluations were performed where were evaluated seven light bar steering systems, one auto-steering system, one steering system operated by an electronic monitor, a steering system operated by a steel cable and a system oriented by a foam marker. The same developed methodology was applied on these four field test. This developed methodology was based on measure the steering error compared to the programmed alignment directly on the field, where an operator was guided by the evaluated steering system. The tests were made in straight line and curve operations. The field methodology presented in this work was successful. The advantage of this methodology is the possibility of reflection of all factors involved in the errors and the possibility of the errors measured in the field directly by the final user...(Complete abstract click electronic access below)
Doutor
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Törnroth, Oscar, and Truls Nyberg. "Design and Implementation of a Strategy for Path Tracking on Autonomous Heavy-Duty Vehicles." Thesis, Linköpings universitet, Fordonssystem, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-149266.
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In this thesis, a combined feedforward and feedback controller for improved path tracking on autonomous heavy-duty vehicles is designed and implemented. The steering wheel is controlled in order to follow a reference curvature, computed by a higher-level MPC, responsible for minimizing the distance to a planned path. The steering dynamics, from steering wheel via wheel angles, to a measurable vehicle curvature, is modeled, and a conversion from desired curvature gain to input angle to the steering wheel is derived. Tests with an autonomous Scania R580 show that the desired curvature can be followed with satisfactory small error, both in a designed slalom path and on a more generic test track. By utilizing future curvature values computed by the MPC, a non-causal feedforward controller can reduce the delay from input to the steering wheel to a measured response in curvature, by almost two thirds, compared to the currently implemented solution. Compared to an open-loop control design, tests in simulation show that a feedback controller can reduce errors in curvature gain. However, with the identified steering dynamics and the improved conversion from steering wheel angle to curvature, no further improvement in the curvature gain was seen when implementing the feedback controller in the test vehicle. Care must also be taken not to introduce instability in the system when the feedback controller is implemented in series with a high-level MPC.Den här rapporten beskriver design och implementering av en regulator med kombinerad framkoppling och återkoppling för förbättrad banföljning av autonoma tunga fordon. Fordonets ratt styrs för att följa en kurvaturreferens beräknad av en överordnad MPC, ansvarig för att minimera avståndet till en planerad bana. Dynamiken i styrningen, från ratten via hjulvinklarna till en mätbar kurvatur för fordonet, är modellerad. En översättning från önskad förstärkning av kurvatur till insignal för rattvinkeln är också framtagen. Tester utförda med en autonom Scania R580 visar att den önskade kurvaturen kan följas med tillfredsställande litet fel, både i en egendesignad slalombana och i en mer generisk testbana. Genom att utnyttja framtida referensvärden för kurvatur beräknade av MPC:n, kan en icke-kausal framkopplande regulator minska fördröjningen från insignal till ratten till en mätbar respons i fordonets kurvatur. Jämfört med den nuvarande lösningen minskas fördröjningen med nästan två tredjedelar. Jämfört med en öppen styrning visar tester i simulering att en återkoppling i regulatorn kan minska stationära fel i kurvatur. Med implementeringen av den identifierade styrdynamiken och den förbättrade översättningen från rattvinkel till kurvatur, syntes dock med återkoppling ingen ytterliggare förbättring i testfordonet. Implementering av den återkopplande regulatorn i serie med den överordnade MPC:n behöver också göras med omsorg för att inte introducera instabilitet i systemet.
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Lind, Bianca. "Beitrag und Erwartungen der Erzeugerverbände an die Digitalisierung der Landwirtschaft." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-211908.
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Fergani, Soheib. "Commande robuste LPV/H infini multivariable pour la dynamique véhicule." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENT053/document.
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L'objectif principale de cette thèse est de développer contrôleurs innovants MIMO pour la dynamique véhicule tout en préservant la stabilité du véhicule dans les situations de conduite critiques. Des stratégies de commandes innovatrices ont été introduites pour résoudre cette problématiques. En effet, ces travaux se base sur travaux l'utilisation de la commande LPV/Hinf pour contrôler simultanément les actionneurs de freinage, braquage et de suspensions pour réaliser les objectives du contrôle.Aussi de stratégies d'estimation du profil de route très intéressant et qui peuvent apporter une solution industrielle très intéressante pour développer des contrôleurs qui assurent adaptative aux différentes conditions de route.Aussi des stratégies de commande tolérante aux défauts actionneurs ont été établi en exploitant les caractéristiques de la commande LPV pour compenser la perte de certains actionneurs (en sachant que la voiture est un système sur actionné). Des implémentations ont été effectuées sur des bancs de test et sur un véhicule réel pour prouver l'efficacité des stratégiesThe main issue of this thesis is to work out new Global Chassis MIMO controllers that enhance the overall dynamics of the vehicle while preserving the vehicle stability in critical driving situations. Many innovative strategies have been explored and finalized to deal with these problematics. Various solutions have been given to deal with the vehicle stability and performance objectives. Indeed, many works based on the LPV/Hinf approach have been developed to control simultaneously the braking, steering and suspension actuators. On the other hand, innovative road profile estimation strategies have been introduced and validated via experimental procedures, providing new cheap and easily implementable techniques to estimate the road profile characteristics. Then, the vehicle control is adapted, depending on the road roughness (since it influences greatly the behaviour and the stability of the car). Several fault tolerant control strategies have been also considered to handle the actuators failures while keeping the vehicle stability, safety and enhancing the dynamical behaviour of the car in dangerous and critical driving situations.The general content of this thesisis as follows :-PART I : Theoretical backgrounds and vehicle modeling.-PART II : Road adaptive control vehicle dynamics.-PART III : Global chassis control using several actuators.Also, during this thesis and using the previous works of the advisors and the thesis results, a Matlab ToolBox "Automotive" has been developed to provide a bench test for the different automotive control studies. Implementations on test beds and real vehicle are also achieved to prove the efficiency of the proposed strategies
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Borretti, Biagio, Nicola Musciagna, Luca Riccò, and Andrea Fornaciari. "Intelligent twin steering system." Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71114.
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This article describes the Dana intelligent Twin Steering System designed for mobile vehicles with two steering axles (i.e. with four steering wheels). Current vehicles with four-wheel steering function are typically equipped with a hydraulic configuration where the two steering cylinders are connected in series. This type of connection highlights some limitations on available power, steering comfort and enabling advanced working functions. Dana evolved this type of hydraulic configuration introducing the possibility to disconnect the rear axle from the front one. In this way the rear axle, through the electronic control of its valve block, allows to improve the steering system performance and introduces advanced steering functions compared to the conventional steering systems.
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Olofsson, Petter, and Jimmy Utterström. "Hydraulstyrning med konfiguration över Bluetooth." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-122408.
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Denna rapport omfattar konstruktionen av ett fristående drivkort med tillhörande mobilapplikation för styrning och konfiguration av ett hydraulsystem. Projektets syfte var att på beställaren Bosch Rexroth ABs begäran undersöka om pump control module (PCM) - en del ur det existerande Spider 3 styrsystemet - kunde användas som en fristående modul. Hårdvara med en Bluetoothmodul skapades och kopplades mot PCM för att möjliggöra kommunikation via Bluetooth. En mobilapplikation utvecklades i Android studio för att tillåta konfiguration från en mobil enhet. Mjukvaran i PCM modifierades för att kommunicera med Bluetooth-hårdvaran över CAN och även för att tillåta analog styrning av pumpen via en strömstyrd ingång. De grundläggande kraven för systemet uppfylldes och en fungerande prototyp kunde uppvisas vid projektets slut. Prototypen visade stor potential men saknade dock viss funktionalitet som vore önskvärd hos en kommersiell produkt.This report encompasses the development of a standalone drive card with an accompanying mobile application for control and configuration of a hydraulic system. The purpose of the project was to - according to an inquiry from the client Bosch Rexroth - investigate whether the pump control module (PCM) from the existing Spider 3 control system could be used as a standalone module. Hardware including a Bluetooth module was assembled and connected to the PCM to allow communication over Bluetooth Low Energy (BLE). A mobile application where developed in Android Studio to allow configuration from a mobile device. The software of the PCM were modified to communicate with the Bluetooth hardware over CAN and also for allowing analog control of the hydraulic pump through a current controlled input.The basic demands for the system were met and a working prototype could be demonstrated at the end of the project. The prototype did show large potential but was lacking some functionality which would be desirable for a commercial product.
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Deingruber, Ondřej. "Robotické vozidlo s využitím RC komponentů." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2021. http://www.nusl.cz/ntk/nusl-449166.
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This thesis covers the topic of controlling RC servos and constructions of robotic vehicles. The goal is to propose a model of robotic vehicle with RC components and other off the shelf components, 3D printing and demonstrate its capabilities. In the thesis, a mobile robot platform was proposed. It uses a single-board computer together with readily available parts and does not require complicated assembly. An optimization algorithm was used for the design of rack and pinion steering. The result of the thesis is the implementation of a robotic vehicle.
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Rodriguez, Orozco Adrian. "Evaluation of an Active Steering System." Thesis, KTH, Reglerteknik, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-109474.
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A steering aid system called active steering is evaluated by simulating different driving events. The active steering solution, which is taken from a scientific paper, has been implemented in Matlab/Simulink. A vehicle model, also implemented in Matlab/Simulink, is used to form a total system and to compare the two systems: a conventional vehicle and a controlled vehicle. The input to the vehicle model is the steering wheel angle performed by the driver. Simulations are made for a constant speed and a specific changeable road adhesion coefficient. The control system takes the yaw rate as input and derives a steering angle contribution to be added to the drivers command. The motivation for this work is to understand and characterize the response of a vehicle with a complementary steering system. Specific driving events are considered for the simulations such as a wind force disturbance and a severe double lane change. The response of the controlled vehicle is similar to the response of the conventional vehicle for nominal driving, but the steering aid system reduces the effect of wind force disturbances. Improved stability is obtained for the vehicle during slippery road driving.
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Lundström, Adam. "Verification of CEVT Steering System Specification." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-74374.
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This thesis covers the development of a component specification for the steering system of vehicles engineered by CEVT. This includes the components steering column, intermediate shaft, steering gear and tie rods. Due to the reuse of requirements on the component specification from previous projects it now lacks connection to customer needs. A verification of the component specification is necessary to ensure that no redundant or unnecessary requirements are present. The verification was performed through a comparison between a newly established specification and the current one. Identified customer needs were gathered on complete vehicle level and classified according to customer satisfaction with respect to implementation according to the Kano model. The subjective customer needs were translated into objective, quantifiable metrics on complete vehicle level that was then decomposed onto component level. Customer needs and metrics were then correlated against each other and visualized through the House of Quality matrix. Numeric targets for the metrics were based on its impact on customer satisfaction. This resulted in 50 identified metrics connected to the steering column and 58 metrics connected to the steering gear. The comparison resulted in 22 deviations between the new and current specification where 8 metrics was identified for further investigation. Further development would include investigation of these 8 identified metrics and relate targets to competitors’ performance.
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Gunnarsson, Sandra, and Anna Kröhnke. "Ledarskapets roll vid förändringsarbeten : Centralt styrda förändringar som verkar på flera enheter." Thesis, Linnéuniversitetet, Institutionen för informatik (IK), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-78290.
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Denna studie har syftat till att undersöka ledarskapets roll vid centrala förändringsarbeten som verkar på flera enheter. Mer än två av tre förändringar misslyckas idag på grund av bland annat bristande ledarskap. Tidigare har dock inte ledarskapet vid centralt styrda förändringar som verkar på flera enheter studerats. Syftet med studien har undersökts genom att studera en implementering av Standard Operating Procedure (SOP) på IKEA. Förändringen har styrts från ett nationellt huvudkontor och verkat på flera varuhus. Tidigare forskning visar att implementering av Standard Operating Procedure aldrig tidigare undersökts i globalt privatägda företag som IKEA, utan endast inom vården och medicinsk forskning. Datainsamling har genomförts genom intervjuer med ledare på tre olika IKEA- varuhus. Studien har baserats på teorier kring förändringsprocesser och ledarskap så som Lewins Change model, John Kotters Accelerate’s 8-Step model samt William Bridges Bridges Transition Model. Utifrån en analys av de intervjuer som gjorts och den teori som legat till grund för undersökningen har flera faktorer kopplat till ledarskap identifierats som centrala. Några av de mest väsentliga delarna som identifierats är vikten av att använda personliga mål kopplade till förändringen, tydligt förmedla vision och syfte, inkludera medarbetarna i förändringsarbetet samt att säkra ett starkt stöd från organisationens ledning. Genom att säkra dessa delar så bemöts motstånd och medarbetare motiveras att genomföra förändringen. Slutsatserna i denna studie visar på många likheter med studerad teori. Det är därför lämpligt att använda teorierna i liknande kontexter där centralstyrda förändringar genomförs på flera enheter.The aim of this study has been to look deeper into leadership within centralized managed changes that take place in multiple units. More than two thirds of changes within companies fail due to bad leadership. Leadership within centralized managed changes that take place in multiple units have never been studied before. The purpose with this study has been fulfilled by studying an implementation of a Standard Operating Procedure (SOP) at IKEA. The implementation has been managed from a national head office and the change has been executed within a number of IKEA-stores. No previous research has been found that studies the implementation of Standard Operating Procedure within global private owned companies. Found studies of SOP has been within health care and medical research. To gather data, interviews have been made with leaders at three different IKEA- stores. Theories that have been used are mainly based around change process and leadership. The included theories are Lewins Change model, John Kotters Accelerate’s 8- Step model Iand William Bridges Bridges Transition. A number of significant factors related to leadership was identified through analysis of the gathered data and theories. Some of the most essential parts that was identified were the importance of using personal goals connected to the goals of the change, to clear communicate the vision and purpose of the change, include the co-worker in the change process and secure a strong support from the management. By assuring these factors the resistance against the change will be handle in a good way and the co-workers will get motivated to carry through the change. The conclusions found in this study shows similarities with the studied theory. It is therefore appropriate to use these theories where centralized managed changes take place at multiple units within a similar context that is investigated in this study.