Formula Student Car Stability

Abstract: This thesis investigates the impact of varying passive components on the stability of a Formula Student race car. The study was conducted using a 7-post model and a lateral model, both of which were derived using Lagrangian methods and state-space modelling techniques. These models were then validated and adjusted using logged data. The 7-post model was verified through damper displacement and damper velocity distribution. Additionally, the models were used to simulate different cornering capabilities and setup alterations, with a focus on the effects of damping, anti-roll bar, toe angles, and springs on the car’s lateral dynamics. The primary findings reveal that damping has a significant impact on all modes, drastically influencing the lateral conditions of the car. In contrast, the anti-roll bar and toe angles had a minimal effect on the lateral dynamics compared to the dampers. The springs were found to increase oscillations and the amplification of the respective modes, but also decrease the damping ratio, suggesting that care should be taken in finding a spring rate that is soft enough to complement the dynamics without compromising the effect of other modes. The study also explored how the static toe angles of the car affect the lateral dynamics, noticing differences in the side-slip angles as well as the lateral velocities for all the changes compared to a zero-toe setting. The analysis was expanded by using the linearized lateral dynamics and transient values simulated, providing insights on how the yaw and side-slip damping changed over a lap, and how the real and imaginary poles shifted over a lap. The thesis concludes with recommendations for future research, suggesting the incorporation of the lateral model with the 7-post model and the computation of the optimum value for each dynamic input for a given transient condition. It also highlights the potential benefits of utilizing industry software such as ChassisSim for further analysis.