Nonlinear coupled dynamic modeling and deviation index quantification for brake deviation in heavy-duty commercial vehicles

Conventional multibody dynamics models often exhibit significant discrepancies in representing the nonlinear mechanical characteristics of critical subsystems under real-world operating conditions, leading to insufficient accuracy in dynamic characteristic analyses. Additionally, objective quantification of brake deviation remains a challenging task. To address the issue of brake deviation in heavy-duty commercial vehicles, this study proposes a high-precision multibody dynamics modeling approach and an objective method for quantifying brake deviation. This research develops a high-fidelity multibody dynamics model for brake deviation analysis by integrating a nonlinear model of the leaf spring-axle coupling system and a geometric-kinematic coupling model of the steering system. Furthermore, through systematic analysis of the multi-parameter coupling mechanisms influencing brake deviation, an evaluation index driven by key contributing factors is designed to quantify brake deviation. The proposed methodology is validated by comparing the simulation results of the high-fidelity multibody dynamics model with experimental data, including kinematics and compliance bench test data and full-vehicle brake deviation test results. The validation demonstrates the feasibility and exceptional accuracy of the developed model and computational framework. This research provides a robust theoretical foundation for optimizing commercial vehicle braking systems and offers critical practical guidance for enhancing vehicle safety performance.