The diploma thesis, which belongs to the area of vehicle dynamics, deals with the issue of suspension of trucks cabins. In particular, it focuses on the suspension of a race truck cab such as the Rally Dakar. Includes an overview of truck suspension (especially cabs), driving comfort assessment methods and the impact of vibration on human. To verify the suitability of using different cab suspension concepts, a multibody model was built in program MSC ADAMS. Suitable primary suspension has been found appropriate for this model. Cab suspension was tested for driving safety, but first for driving comfort.

Truck drivers are exposed to vibrations all day as a part of their work. In addition to repetitive motion injuries the constant vibrations add to the fatigue of the driver which in turn can have safety implications. The goal of this research is to lower the vibrations an occupant of a class 8 semitruck cab sleeper is exposed to by improving the ride quality. Unlike prior research in the area of ride comfort that target the chassis or seat suspension, this work focuses on the cab suspension. The current standard in cab suspensions is comprised of some type of spring and passive damper mechanism. Ride improvements can most easily be accomplished by replacing the stock passive dampers with some type of controllable damper; in this case Magneto-Rheological (MR) dampers. MR dampers can change damping characteristics in real time, while behaving like a passive damper in their OFF state. This means that in case of a failure to the power supply, the dampers still retain their functionality and can provide some level of damping. Additionally, MR dampers can be packaged such that they do not require any redesign of mounting bracketry on the cab or the frame, their use as a retrofitable device. The damper controller is based on the skyhook control policy pioneered by Karnopp et al. in the 1970s. A variation on skyhook control is chosen called no-jerk skyhook control. A controller called Hierarchical SemiActive Control (HSAC) is designed and implemented to allow the no-jerk skyhook controller to adapt to the road conditions. It also incorporates an endstop controller to better handle the limited rattle space of the cab suspension. The development and initial testing of the controller prototype is done in simulation using a model of the cab and its suspension. The model is derived from first principles using bond graph modeling. The controller is implemented in Simulink to ease the transition to hardware testing. The realtime prototype controller is tested on a class 8 semitruck in a lab environment using dSPACE and road input at the rear axles. The laboratory results are veried on the road in a series of road tests on a test truck. The road tests showed a need for HSAC controller. The HSAC is implemented on the test truck in a final prototype system. The test results with this system show signfiicant improvements over the stock passive suspension, especially when dealing with transient excitations. The overall research results presented show that significant ride improvements can be achieved from a semiactive cab suspension. / Ph. D.

This study aimed at defining useful guidelines for the design of an armored truck cab. Particularly, the quality and performance of ballistic steel were defined, considering not too high demanding requirements. Two steel grades, corresponding to hardness of 500 HB and 600 HB, and three different suppliers were selected. After dividing the truck cab into main areas, a FEM simulation was performed. The investigated model considered a specific standardized threat to impact against a double layer steel protection. Due to the high strain rates involved, the formation of adiabatic shear bands has been observed. However, the main purpose of the model was to find an ultimate thickness protection layout of armored steel plates. Thereby, the thicknesses to be attributed to the various components of the main areas could be estimated. Two alternatives were therefore hypothesized: the first considering the critical thickness case of penetration, and the second, an oversized version, supposed to be more resistant to penetration. It was thus possible to estimate the weight of the truck cab for the two above mentioned alternatives, and verify such hypothesized weight complied with the assigned requirement. A possible cutting operation was then considered in order to optimize the use of the steel plates. An estimation of the pre-series production costs of was finally derived. / Denna studie gjorde det möjligt att definiera användbara indikatorer och följa en möjlig multitasking-strategi för utformningen av en bepansrad lastbilshytt. Fallstudien syftade till att definiera kvalitet och prestanda av stål, vilket är ett av de vanligaste materialen för skydd, främst i de fall där kraven inte är så stora. Två stålkvaliteter motsvarande hårdhetsvärdena 500 HB och 600 HB valdes från var och en av tre materialleverantörer. Efter att ha delat upp truckhytten i några huvudområden startades en FEM-simulering med programvara från Impetus Afea. Modellen behandlade ett specifikt hot som var större än det önskade kravet på ett dubbelskiktsskydd. På grund av de inblandade höga deformationshastigheterna har bildningen av adiabatiska skjuvband observerats. Huvudsyftet med modellen var emellertid att hitta en ultimat skyddslayout för tjockleken, så att de tjocklekar som skulle tillskrivas de olika komponenterna i huvudområdena kunde härledas. Två alternativ antogs därför, det ena med tanke på den ultimata tjockleken och den andra med tanke på en skyddslayout som antas vara mer motståndskraftig mot penetrering. Det var således möjligt att uppskatta hyttens vikt för de två alternativen och kontrollera att den uppfyllde de fastställda kraven. Därefter övervägdes en möjlig skäroperation för att optimera användandet av de tillgängliga stålplattorna.