Analys av instyrning och rolldynamik

Sammanfattning: When driving hard and cornering on a circuit good control of a car’s roll is desired, so the car reaches steady state quickly but yet in a controlled fashion. This control is mainly given by the combination of the cars springs, shock absorbers and anti-roll bars. The aim of this report is to investigate, analyze and measure a Porsche Boxster’s turn in behaviour and roll dynamics as well as with the aid of simulation results give suggestions for improvement of the previous mentioned combination. Two different simulations were made, one based on a simpler model that was based on an evolved version of the bicycle model in Matlab and one was more advanced model in the simulation software rFactor. Measurements of the real car was made using a GPS-based measurement system. The results of the simulations and the measurements were compared which showed acceptable correlation between the models and reality. The results were analyzed further, which showed that the car’s suspension system was underdamped. Therefore the first suggestions for improving the car’s roll dynamics are an increase of the car’s roll stiffness of 20 per cent as well as an increase of the hardness of the shock absorbers of 50 per cent.