This thesis compares Model Predictive Control (MPC) and Proportional-Integral (PI) control in a pin-on-disc tribometer. The tribometer consists of a geared Direct Current (DC) motor driving a flywheel and a voice coil actuating a pin onto the surface of the flywheel. The contact surface of both pin and disc can be replaced with the desired material. The system is first modeled, and both conntrollers are derived from the models and Matlab and Simulink. A PI-cascade controller is used for the disc while a single PI controller is used for the pin. The PI controller is derived using the pole placement, the MPC is derived using the Simulink MPC-designer.  The control methods are evaluated using the Root Mean Sqaure Error (RMSE), percentage overshoot and rise time of step responses from two cases: The ideal case and the operational case. The ideal case contians minimal disturbance as only one actuator is operating at a time. The operational case intends to depict the future use case of the test rig where both actuators are operating simultaneously.  Statistical analysis is conducted as a three was Analysis of Variance (ANOVA) between controller (MPC/PI), case (ideal/operational) and actuator level (40/80 N or 100/200 rpm). In conclusion the MPC has a faster rise time but a higher RMSE than the PI controller in both the ideal and operational case when controlling the disc application of a tribometer. No significant difference in overshoot is established in the disc application of the tribometer. Considering the pin system of the tribometer, no conclusion can be drawn. The main factor being the large impact of the noise at the sampling frequency. This causes failure of the controllers in the operational case. / Denna avhandling jämför Model Predictive Control (MPC) och Propertionell-Integral (PI) kontroll i en stift-på-skiva tribometer. Tribometern består av en likströmsmotor med en växellåda som driver ett svänghjul, och en talspole som är kopplat till ett stift som i sin tur applicerar kraft på svänghjulets yta. Kontaktytan för både stift och skiva kan ersättas med önskat material. Systemet modelleras först, och de båda reglersystemen härleds från modellerna i Matlab och Simulink. En PI-kaskad kontroller används för skivan medan en enkel PI-kontroller används för stiftet. PI-kontrollern härleds med hjälp av polplacering MPC-kontrollern härleds med hjälp av MPC-designern i Simulink.  Reglermetoderna utvärderas med hjälp av kvadratroten ur medelkvadratavvikelsen (RMSE), procentuell översläng och stigtid för stegsvar från två fall: Det ideala fallet och de operativa fallet. Det ideala fallet innehåller minimala störningar eftersom endast ett ställdon åt gången är i drift. Det operativa fallet är avsett att representera det framtida användningsområdet för testriggen där båda ställdonen är i drift samtidigt.  Den statistiska analysen utförs som en trevägs Anlysis of Variance (ANOVA) mellan kontroll (MPC/PI), fall (idealt/operativt) och nivå (40/80 N eller 100/200 rpm). Slutsatsen är att MPC-kontrollern har en snabbare stigtid med en högre RMSE än PI-kontrollern i både idealfallet och driftfallet vid styrning av skivan i en tribometer. Ingen signifikant skillnad i översläng konstaterades i skivan. Ingen slutsats kan dras när det gäller drivning av tribometerns stift. Den huvudsakliga faktorn är den stora mängden störningar vid samplingsfrekvensen. Detta leder till att kontrollerna misslyckas in det operativa fallet.

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The aim of this study is to examine intangible aspects of medieval church architecture from an art historical perspective, by using the theoretical frameworks of  the theologist Alf Härdelin’s theory on multidimensionality and the philosopher of languages  John Langshaw Austin’s the­ory on speech acts and performativity. It studies the relationship between church architecture and liturgy during the 15th century. This case study’s main material is the Upland parish church Ärentuna and the liturgical sources Missale Upsalense novum (1513) and the devotional book Siælinna thrøst (15th century). The interior of the church has been examined to understand how the church interior may have been furnished during the 15th century.  During the 15th century the church had many more altars and devotion pictures than what one can see in the current furnishings of the church. There is a narratological succession in the construction of the building, as well as the iconographical motifs, from West to East, thus the meaning of it becomes increasingly sacred. In that way, the construction of the building, as well as the wall paintings converses, with the liturgy – which has its core in the choir. When lay­people entered the sacred space of the church, they perceived things in a specific order, which creates a sense of order and cohesion within the liturgy. The study found that liturgy produces meaning in the church architecture by giving a visual expression to faith through images. Through performative speech acts found in the liturgy, a multidimensional experience is created by the (theological) fact of Christ's presence in the church. The nave's paintings enhance the visitor’s experience of the church interior as an eternal heavenly presence with motifs such as the Seven days of Creation, the Ten Commandments, the Passion of Christ and finally the Last Judgment.