Braking Judder Test and Simulation Analysis of Commercial Vehicle 2024-01-2342

Brake judder affects vehicle safety and comfort, making it a key area of research in brake NVH. Transfer path analysis is effective for analyzing and reducing brake judder. However, current studies mainly focus on passenger cars, with limited investigation into commercial vehicles. The complex chassis structures of commercial vehicles involve multiple transfer paths, resulting in extensive data and testing challenges. This hinders the analysis and suppression of brake judder using transfer path analysis. In this study, we propose a simulation-based method to investigate brake judder transfer paths in commercial vehicles. Firstly, road tests were conducted to investigate the brake judder of commercial vehicles. Time-domain analysis, order characteristics analysis, and transfer function analysis between components were performed. Subsequently, a multi-body dynamics model of the commercial vehicle was established using ADAMS software, and the effectiveness of the model in predicting brake judder characteristics and transfer functions was verified through experiments. Under braking conditions, transient simulation analysis was carried out to obtain the acceleration of key components along each transfer path. The contribution of each component was then determined using a transfer path analysis method. Research shows that judder causes larger vibrations near the excitation end, showing clear order relationships at 2-4, 6, and 9 orders. However, components like the steering wheel, brake pedal, and cab seat have smaller vibrations with no clear order relationships. Modifying the structure of the steel plate spring can reduce braking judder. The simulation model accurately predicts the time-domain and frequency-domain characteristics of braking judder.