Modeling and Simulation of Steady State Handling Characteristics of Formula Vehicle with Antiroll Bars

Antiroll bar plays an important role in rollover stability of the vehicle. But not only does it limit the vehicle roll during cornering, but also alters the lateral load transfer between the tracks, which in turn affects the cornering performance of the vehicle. This paper deals with the design and mathematical modeling of antiroll bars to reduce the body roll of the vehicle from 1.5°/g to less than 1.0°/g. Rear bar uses a conventional torsion type bar but the front anti roll mechanism is an unconventional antiroll bar using a rotating double cantilever mechanism. Mathematical modeling is done for pushrod rod actuated antiroll mechanisms to simulate its non-linear roll rates. Antiroll bars for front and rear are designed for the calculated stiffness. Finite Element Analysis of antiroll bar and its components is done and the mechanism is tested on the vehicle. Steady state tire model parameters are generated by curve fitting tire testing data into pacejka coefficients. Then the vehicle mathematical model is built and simulated in multi-body simulation tool CarSim for various steady state and transient response tests like skidpad and double lane change. The effect of various antiroll bar configuration on front and rear to achieve the desired roll rate and handling characteristics of the vehicle. The use of Antiroll bar allowed to use softer spring rates and reduce the effective roll rate of the vehicle to 0.98 °/g. It also reduced the skidpad time by 1.4% and the autocross timings were reduced by 0.4 seconds per lap.