Academic literature on the topic 'Framkoppling'

Hydrauliska stötdämpare har länge varit en central komponent på både bilar och motorcyklar. Stötdämpare påverkar fordonets komfort, väghållning och köregenskaper. Dessa olika egenskaper kräver ofta helt olika typer av dämpning och med vanliga passiva dämpare blir resultatet ofta en kompromiss av samtliga dessa. Kompromisserna har lett till utvecklingen av en stötdämpare med ställbar dämparkarakteristik som är tänkt att ersätta passiva dämpare. Öhlins Racing säljer idag ett semiaktivt stötdämparsystem som kallas CES, Continously controlled Electronic Suspension, där dämparkarakteristiken styrs av en tryck- och flödeskompenserad CES-ventil. CES-ventilen är strömstyrd via en ECU, Electronic Control Unit, som monteras på fordonet. Möjligheterna att förbättra fordonens egenskaper är stora men regleringen av dämparen är kritisk för prestandan. Examesarbetet syftar till att via experimentella laborationstester förbättra dämparens prestanda genom att förbättra styrningen av systemet. Det visar sig att den nuvarande reglersystemet lider av en tidsfördröjning, varför en stor del av examensarbetet fokuserar på att minimera detta. Resultaten visar att då hastigheten skattas med ett Kalmanfilter, som tar hänsyn till både dämparens position och acceleration, kan tidsfördröjningar nästan helt elimineras. Elimineringen av tidsfördröjning visar sig förbättra prestandan avsevärt. För att ytterligare öka prestandan hos systemet introduceras även en accelerationsframkoppling.

ABB Surge Arrestors in Ludvika have for a long time had a problem to keep the moisture at a steady state in the production of their ZnO-powder, that is used to produce varistors.

Some black-box models of the spray drying process have been designed and evaluated to find a solution for the problem. After evaluating the collected data it has been found that variations in the supply voltage causes control difficulties for the operator. A cascade control system was designed, consisting of three PI control loops designed with lambda tuning. The disturbance in the supply voltagewas used as a feed forward in the control system.

At the end of the project the control system was installed, and tests were made to verify the functionality of the regulator. It was shown that most of the variations in the moisture of the powder could be eliminated using small resources, through purchase of a process controller and four power meters. The

standard deviation in the moisture was decreased from a level of 0.32%, measured when the process was manually controlled, down to 0.07% measured when the control system was used. This also solved the given problem.

Due to increasing regulations regarding new diesel vehicles particulate matteremissions the new Scania truck, Scania Euro 6, has been equipped with a particulatefilter. This component effectively stores the particles in the exhaust gas but must becleaned in order to prevent itself from clogging. The filter is cleaned through aprocess named regeneration which is a thermodynamic process in which thetemperature of the filter is raised through fuel supplied to the exhaust gas.The purpose of this thesis is to contribute to the development of improved controlstrategies of the temperature during the regeneration process through thedevelopment of model-based controllers. These controllers are designed in order tohave good performance in stationary as well as automatic regeneration.In order to develop these model-based controllers a model of the system isconstructed. The model is described as a linear thermodynamic grey-box model withflow varying parameters, showing good results in validation.The model provides a simulation environment during the controller design, which isfocused around the development of linear regulators with the exhaust gas mass flowas a scheduling variable whose size determines controllers’ mode of operation. Basedon this approach an IMC controller and a PI controller with a combined feedforwardterm are developed and analyzed. Both controllers show good performance in termsof robustness and reference tracking. The authors' firm opinion is that controlstrategies with the exhaust gas mass flow as a scheduling variable is suitable forkeeping control of the temperature in the particulate filter during regeneration.

I denna rapport utreds olika metoder för att kunna reglera vattennivån i vattenkraftverket Avesta Lillfors i Dalarna. Två kraftverk ligger endast 900 m uppströms och detta gör att svarstiderna blir korta och regleringen blir lätt nervös. Att använda sig av vattennivåreglering i ett kraftverk för-enklar dess styrning då anpassning till inflödet sker automatiskt. En flödestabell har tagits fram genom mätningar i turbinen, med hjälp av Winter-Kennedy-metoden. Denna tabell används för att kunna fram-koppla regulatorn och därmed dämpa stora variationer i inflödet. Dessu-tom har en modell av älven skapats och testats med en återkopplad PID-regulator. Utefter dessa tester har lämpliga parametrar tagits fram, som ger önskad stabilitet, noggrannhet och snabbhet. Simuleringar har även gjorts med reglermetoden Fuzzy logic.
This report evaluates different methods to create a stable regulation of the water level in the hydro power plant Avesta Lillfors, in county Dalar-na. Another pair of plants are located just 900 m up the stream, which is why the regulation has to act fast. If the water level can be regulated and automatically adjust to the incoming flow, it facilitates the control of the plant. A flow chart is created from measurements in the turbine, using the Win-ter-Kennedy method. The results are used for feedforward control. A PID-regulator with feedback is also simulated in a model of the river. This helps finding the parameters that provide a stable, accurate and fast regu-lation. Fuzzy logic control has also been simulated.

Inpipes produktion av liners sker idag till stor del manuellt. I syfte att minska variansen på produktkvalitet, råvaror och öka processens hastighet undersöktes möjligheterna att elektroniskt mäta utbuktningarna som uppstod i processen. Därefter undersöktes processens egenskaper inför att använda mätvärdena i en passande reglerstruktur.  Efter en urvalsprocess i samråd med Inpipe och iLogik ansågs två av fem mätmetoder intressanta att gå vidare med i projektet. Utifrån dem togs beslut att undersöka hur beröringsfria givare med ultraljud och optisk teknik presterade på att mäta utbuktningarnas höjd. Mätningar utfördes både i testmiljö och i fabrik med laser, ultraljudsgivare och manuellt. Resultat visade att ultraljudsgivaren hade störst precision där optiska givaren tenderade att ge ett konstant mätfel. Processens utmanande egenskaper inför en reglering av bulorna fastslogs till att främst innefatta långsamma hartsflöden, varierande produktlängd och ytvariationer. Trots utmaningar som vågor på produktens yta samt ultraljudsgivarens mätavvikelse på lutande produkt resulterade arbetet i att ultraljudsgivaren bör fungera tillfredställande till att mäta utbuktningarnas höjdförändringar och implementeras i en reglering. Utifrån processens egenskaper och inom ramen för denna studie anses framkoppling som en lämpad reglerstruktur, däremot krävs det fortsatta undersökningar för att bekräfta eller dementera det.
Inpipes production of liners is today substantially done manually, in order to reduce the variance of product quality, raw material and production speed, the possibility to electronically measure the swell of the product in the process was examined. The property of the industrial process was also examined to find a suitable regulation structure.  A presentation of different methods of measurement was conducted, Inpipe chose two of them as specially interesting. It included measurement of ultrasound and optical laser sensors and decision to examine their precision on the liners swell was made. The measurement was done in controlled environment on a product dummy and in factory on the real liner. The ultrasound sensor proved to give the highest precision while the laser sensor indicated to measure a constant offset. The most challenging properties of the industrial process was determined to be slow resin flows, varying product length and surface variation on the product. Despite challenges as wave on the liners surface and the ultrasounds sensors inability to measure the liners slope, the project led to recommend the ultrasound sensor for measure the height of the liners swell and use the value in a regulation of the process. In theory feed forward regulation seems to suit the properties of the industrial process, but further work must be done to really confirm or deny that claim.

Increased oil prices and environmental issues have increased a need of loweringthe emissions from and the fuel consumption in heavy construction machines. Anatural solution to these issues is a lowered input power through downsizing ofthe engine. This implies a demand on higher transmission efficiency, in order tominimize the intrusion on vehicle performance. More specifically, alternatives tothe conventional torque converter found in heavier applications today, must beinvestigated. One important part of this is the task of controlling the transmissionwithout jeopardising the advantages associated with the torque converter, such asrobustness and controllability.In this thesis, an alternative transmission concept for a backhoe loader is investigated.The studied concept is referred to as a 2-mode Jarchow power-splittransmission, where a mechanical path is added to a hydrostatic transmission inorder to increase transmission efficiency. The concept is evaluated in computerbased simulations as well as in hardware-in-the-loop simulations, where a physicalhydrostatic transmission is exposed for the loads caused by the vehicle duringvarying conditions. The loads are in turn simulated according to developed modelsof the mechanical parts of the vehicle drive line.In total, the investigated concept can be used instead of the torque converterconcept, if the hydrostatic transmission is properly controlled. The results alsoshow that there is a high possibility that the combustion engine in the backhoeloader can be downsized from 64 kW to 55 kW, which would further increase thefuel savings and reduce the emissions.