System design improvement to eliminate brake-induced vehicle vibration

Vehicle quality is strongly influenced by vehicle sensitivity to brake-induced vibration. When drivers can detect brake-induced vibration, it negatively impacts their satisfaction with a vehicle's performance and quality. The suspension is the primary chassis sub-system that transmits vibration from the brakes to the rest of vehicle. Since the suspension system is directly linked with the brake, tyre/wheel assembly, sub-frame and steering system, its coupled vibration is very complicated. The current paper presents a study of chassis system vibration mode identification and a design strategy for reducing system sensitivity to brake-induced vibration. A system integration approach is used to derive an improvement strategy that can potentially make a vehicle more robust to the vibration caused by torque variation of the brakes. The approach links suspension, steering and sub-frame vibration characteristics, system identification techniques, kinematics modeling and robust design principles in a systematic fashion. The concept and method have been successfully demonstrated on a typical mid-size vehicle.