Integrated Virtual Approach for Optimization of Vehicle Sensitivity to Brake Torque Variation

Brake judder is a brake induced vibration that a vehicle driver experiences in the steering wheel or floor panel at highway speeds during vehicle deceleration. The primary cause of this disturbance phenomenon is the brake torque variation (BTV). Virtual CAE tools from both kinematics and compliance standpoints have been applied in analyzing sensitivities of the vehicle systems to BTV. This paper presents a recently developed analytical approach that identifies parameters of steering and suspension systems for achieving optimal settings that desensitize the vehicle response to BTV. The analytical steps of this integrated approach started with creating a lumped mass noise-vibration-harshness (NVH) control model and a separate multi-body dynamics (MBD) suspension model. Then, both models were linked to run in a sequence through optimization software so the results from the MBD model were used as quasi-static inputs to the lumped mass NVH model. Considering control factor parameters settings in the presence of noise factors, a case study revealed in this paper was conducted using Taguchi method for a Design for Six Sigma (DFSS) study. The benefit of this process is to design a robust system against BTV. This virtual optimization process can be implemented early during the vehicle design phase for performance target settings; it also provides tuning solutions for warranty reduction due to brake judder issues.