Vibrational behaviour of braking deceleration in passenger cars during emergency braking in urban environment

Abstract This study investigates the dynamic behaviour of a vehicle during extreme braking events, focusing on the oscillations in braking torque generated by the braking system and wheels. These oscillations are transmitted through the suspension system to the vehicle structure, affecting the characteristics of the overall acceleration during braking. The analysis of longitudinal acceleration dynamics reveals that significant vibrations are predominantly observed during the phase of maximum negative acceleration, regulated by the anti-lock braking system (ABS) and traction control. The frequency spectrum of acceleration during this period is highly sensitive to the initial braking conditions. As the vehicle’s speed at the moment of braking increases, the frequency spectrum becomes more discrete, and the amplitudes of higher-frequency harmonics increase.